Mississippi Valley Division

Changes in Hydrology and 

Suspended-Sediment 

Transport in the Mississippi 

River Basin over the 

Past Century

MRG&P Report No. 34 • June 2020

Mississippi River Geomorphology & 

Potamology Program 

MRG&P Report No. 34 

June 2020 

Changes in Hydrology and Suspended-Sediment 

Transport in the Mississippi River Basin over the 

Past Century

Andrew Simon, Kimberly Artita, and Gail Simon 

Cardno

P.O. Box 1236

Oxford, MS 38655

Stephen Darby and Julian Leyland 

Department of Geography and Environment

University of Southampton

Highfield

Southampton, SO17 1BJ

UK

Final report 

Approved for public release; distribution is unlimited.

Prepared for US Army Corps of Engineers

Washington, DC 20314-1000

Under Project 127672; "Mississippi River Geomorphology and Potamology Program"
MRG&P Report No. 34 ii

Abstract

Since about 1900, widespread changes in hydrology across the Mississippi 

River Basin have occurred, resulting in important changes in the delivery 

of water and sediment to the Lower Mississippi River (LMR). This is due 

to a combination of natural and anthropogenic factors. There have been 

increases in annual precipitation and 1- to 7-day totals over large parts of 

the basin. Changes in seasonal distributions were also identified, as were

increases in hurricane-related rainfall.

Streamflow to the LMR has increased significantly over the past 100 years. 

Median water yields have increased across most of the mid-continent and 

decreased in the western-most parts of the Missouri and Arkansas River 

basins. Suspended-sediment loads to the LMR have dramatically declined. 

The Lower Mississippi River is receiving about 500 million tonnes per year 

less suspended sediment today than in the 1940s (616 Mt/y to 98 Mt/y).

Human impacts on hydrology and sediment transport throughout the 

basin are important. In the mid-continent, water yield per unit 

precipitation showed increases, but markedly decreased in the western 

parts of the basin. Decreases can be attributed to the construction of 

thousands of dams, associated flow regulation, withdrawals for 

agriculture, and to a lesser extent, the increased evaporation behind 

impoundments.

DISCLAIMER: The contents of this report are not to be used for advertising, publication, or promotional purposes. Citation 

of trade names does not constitute an official endorsement or approval of the use of such commercial products. All product 

names and trademarks cited are the property of their respective owners. The findings of this report are not to be construed 

as an official Department of the Army position unless so designated by other authorized documents.

DESTROY THIS REPORT WHEN NO LONGER NEEDED. DO NOT RETURN IT TO THE ORIGINATOR.
MRG&P Report No. 34 iii

Contents

Abstract.................................................................................................................................... ii

Figures and Tables...................................................................................................................v

Preface.................................................................................................................................... xi

1 Introduction ......................................................................................................................1

Background..................................................................................................................1

Objectives.....................................................................................................................3

Approach......................................................................................................................4

Spatial divisions ........................................................................................................................... 5

Temporal divisions ....................................................................................................................... 9

2 Data Requirements, Sources, and Availability ...........................................................10

Daily precipitation data .............................................................................................10

Mean-daily streamflow and peak-annual streamflow.............................................11

Suspended-sediment concentrations ..................................................................... 12

National inventory of dams...................................................................................... 13

Daily pan-evaporation observations........................................................................ 13

Geospatial data .........................................................................................................14

3 Methodology...................................................................................................................15

Precipitation analysis ................................................................................................15

Streamflow analysis ..................................................................................................17

Calculation of water yield and precipitation-weighted water yield ........................ 18

Trend analyses...........................................................................................................19

Peak-streamflow analysis ........................................................................................ 20

Annual-evaporation rates......................................................................................... 20

Determination of annual suspended-sediment yields ............................................21

4 Results and Discussion .................................................................................................25

Precipitation trends.................................................................................................. 25

Annual trends............................................................................................................................. 25

Peak annual trends.................................................................................................................... 26

Seasonal trends ......................................................................................................................... 31

Peak seasonal trends ................................................................................................................ 37

Hurricane-related precipitation trends .....................................................................................44

Summary of precipitation results ...............................................................................................49

Water yield trends..................................................................................................... 50

Annual trends............................................................................................................................. 50

Peak annual trends.................................................................................................................... 51

Seasonal trends ......................................................................................................................... 55

Peak seasonal trends ................................................................................................................ 60

Summary of water-yield results.................................................................................................65
MRG&P Report No. 34 iv

Trends in precipitation-weighted water yield........................................................... 67

Annual trends............................................................................................................................. 67

Potential evaporation from NID impoundments ......................................................................74

Peak annual trends.................................................................................................................... 79

Seasonal trends ......................................................................................................................... 82

Peak seasonal trends ................................................................................................................ 87

Summary of precipitation-weighted water yield results: anthropogenic influences ..............89

Streamflow trends from index stations................................................................... 90

All index stations ........................................................................................................................ 90

Major (HUC-2) index stations.....................................................................................................96

Summary of streamflow trends from index stations results .................................................105

Peak streamflow from HUC-4s............................................................................... 106

Sediment yield........................................................................................................ 108

Values and trends at the effective (Q1.5) discharge ...............................................................109

Annual trends...........................................................................................................................114

Trends in annual sediment delivery to the Lower Mississippi from major index 

stations.....................................................................................................................................119

Summary of sediment-yield results.........................................................................................122

5 Summary ...................................................................................................................... 124

References.......................................................................................................................... 126

Appendix A: GHCND Gages............................................................................................... 132

Appendix B: USGS Gage Information .............................................................................. 134

Appendix C: National Inventory of Dams ........................................................................ 139

Appendix D: Average Monthly Evaporation at NID Impoundments ............................. 142

Appendix E: Precipitation Trends by HUC-4.................................................................... 148

Appendix F: Water Yield Trends by HUC-4....................................................................... 184

Appendix G: Precipitation-Weighted Water Yield Trends by HUC-4............................. 214

Appendix H: Streamflow Trends at Index Stations ........................................................ 232

Appendix I: Peak Streamflow Analysis by HUC-4...................................................... 268

Appendix J: Suspended-Sediment Yields .........................................................................271

Unit Conversion Factors.................................................................................................... 282

Acronyms and Abbreviations............................................................................................ 283

Report Documentation Page
MRG&P Report No. 34 v

Figures and Tables

Figures

Figure 1. Major hydrologic regions (2-digit hydrologic unit codes) and sub-regions 

(4-digit hydrologic unit codes) of the Mississippi River Basin..................................................7

Figure 2. Location of GHCND precipitation gages used in this study...................................10

Figure 3. Location of USGS mean-daily streamflow gages used in this study. ...................11

Figure 4. Location of USGS peak-streamflow gages used in this study...............................12

Figure 5. Location of USGS suspended-sediment stations used in this study....................13

Figure 6. Location of GHCND pan evaporation gages used in this study. ...........................14

Figure 7. Hurricane tracks affecting the Mississippi River Basin (1950–2014).................16

Figure 8. Location of streamflow index stations......................................................................18

Figure 9. Annual streamflow along the Mississippi River at St. Louis, Missouri.................20

Figure 10. Examples of decadal shifts in sediment-transport ratings (including 

equations) from index stations along the Arkansas (top) and Missouri Rivers 

(bottom). The vertical black line represents the Q1.5. .............................................................24

Figure 11. Percent change in annual rainfall for all HUC-4s (top left) and for HUC4s with statistically significant trends only (top right). Change for all HUC-4s 

(bottom), with significant trends shown in blue.......................................................................28

Figure 12. Percent change in maximum, annual 24-hour rainfall for all HUC-4s 

(top left) and for HUC-4s with statistically significant trends only (top right). 

Change for all HUC-4s (bottom), with significant trends shown in blue. ..............................29

Figure 13. Percent change in maximum, annual 7-day rainfall for all HUC-4s (top 

left) and for HUC-4s with statistically significant trends only (top right). Change for 

all HUC-4s (bottom), with significant trends shown in blue. ..................................................30

Figure 14. Percent change in winter rainfall for all HUC-4s (top left) and for HUC4s with statistically significant trends only (top right). Change for all HUC-4s 

(bottom), with significant trends shown in blue.......................................................................33

Figure 15. Percent change in spring rainfall for all HUC-4s (top left) and for HUC4s with statistically significant trends only (top right). Change for all HUC-4s 

(bottom), with significant trends shown in blue.......................................................................34

Figure 16. Percent change in summer rainfall for all HUC-4s (top left) and for 

HUC-4s with statistically significant trends only (top right). Change for all HUC-4s 

(bottom), with significant trends shown in blue.......................................................................35

Figure 17. Percent change in fall rainfall for all HUC-4s (top left) and for HUC-4s 

with statistically significant trends only (top right). Change for all HUC-4s 

(Bottom), with significant trends shown in blue. .....................................................................36

Figure 18. Percent change in maximum daily winter rainfall for all HUC-4s (top 

left) and for HUC-4s with statistically significant trends only (top right). Change for 

all HUC-4s (bottom), with significant trends shown in blue. ..................................................38

Figure 19. Percent change in maximum daily spring rainfall for all HUC-4s (top 

left) and for HUC-4s with statistically significant trends only (top right). Change for 

all HUC-4s (bottom), with significant trends shown in blue. ..................................................39
MRG&P Report No. 34 vi

Figure 20. Percent change in maximum summer daily rainfall for all HUC-4s (top 

left) and for HUC-4s with statistically significant trends only (top right). Change for 

all HUC-4s (bottom), with significant trends shown in blue. ..................................................40

Figure 21. Percent change in daily fall rainfall for all HUC-4s (top left) and for 

HUC-4s with statistically significant trends only (top right). Change for all HUC-4s 

(bottom), with significant trends shown in blue.......................................................................42

Figure 22. Percent change in maximum 7-day fall rainfall for all HUC-4s (top left)

and for HUC-4s with statistically significant trends only (top right). Change for all 

HUC-4s (bottom), with significant trends shown in blue. .......................................................43

Figure 23. Changes in maximum annual, continuous days of hurricane anomaly. ...........45

Figure 24. Changes in total annual days of hurricane anomaly............................................46

Figure 25. Changes in annual hurricane anomaly..................................................................47

Figure 26. Changes in maximum annual, daily hurricane anomaly. ....................................48

Figure 27. Changes in maximum annual, 7-day total hurricane anomaly............................48

Figure 28. Percent change in annual water yield (top left) and for HUC-4s with 

statistically significant trends only (top right). Change for all HUC-4s (Bottom), 

with significant trends shown in blue........................................................................................52

Figure 29. Percent change in annual maximum-daily water yield for all HUC-4s 

(top left) and for HUC-4s with statistically significant trends only (top right). 

Change for all HUC-4s (bottom), with significant trends shown in blue. ..............................53

Figure 30. Percent change in 7-day maximum water yield for all HUC-4s (top left) 

and for HUC-4s with statistically significant trends only (top right). Change for all 

HUC-4s (bottom), with significant trends shown in blue. .......................................................54

Figure 31. Percent change in winter water yield for all HUC-4s (top left) and for 

HUC-4s with statistically significant trends only (top right). Change for all HUC-4s 

(bottom), with significant trends shown in blue.......................................................................56

Figure 32. Percent change in spring water yield for all HUC-4s (top left) and for 

HUC-4s with statistically significant trends only (top right). Change for all HUC-4s 

(bottom), with significant trends shown in blue.......................................................................57

Figure 33. Percent change in summer water yield for all HUC-4s (top left) and for 

HUC-4s with statistically significant trends only (top right). Change for all HUC-4s 

(bottom), with significant trends shown in blue.......................................................................58

Figure 34. Percent change in fall water yield for all HUC-4s (top left) and for HUC4s with statistically significant trends only (top right). Change for all HUC-4s 

(bottom), with significant trends shown in blue.......................................................................59

Figure 35. Percent change in maximum-daily spring water yield for all HUC-4s 

(top left) and for HUC-4s with statistically significant trends only (top right). 

Change for all HUC-4s (bottom), with significant trends shown in blue. ..............................61

Figure 36. Percent change in maximum-daily summer water yield for all HUC-4s 

(top left) and for HUC-4s with statistically significant trends only (top right). 

Change for all HUC-4s (bottom), with significant trends shown in blue. ..............................63

Figure 37. Percent change in maximum-daily fall water yield for all HUC-4s (top 

left) and for HUC-4s with statistically significant trends only (top right). Change for 

all HUC-4s (bottom), with significant trends shown in blue. ..................................................64

Figure 38. Maximum fall 7-day total water yield for select HUC-4s. .....................................65
MRG&P Report No. 34 vii

Figure 39. Percent change in annual precipitation-weighted water yield for all 

HUC-4s (top left) and for HUC-4s with statistically significant trends only (top 

right). Change for all HUC-4s (bottom), with significant trends shown in blue....................70

Figure 40. Annual trends in HUC 0712 (Upper Illinois). Precipitation (top), water 

yield (middle), and precipitation-weighted water yield (bottom)............................................71

Figure 41. Annual trends in HUC1002 (Missouri Headwaters). Precipitation (top), 

water yield (middle), and precipitation-weighted water yield (bottom).................................72

Figure 42. Annual trends in HUC1112 (Red Headwaters). Precipitation (top), 

water yield (middle), and precipitation-weighted water yield (bottom).................................73

Figure 43. Precipitation-weighted water yield in HUC1009 (Powder-Tongue).....................74

Figure 44. NID impoundments in Iowa by completion date (left) and cumulative 

surface area of NID impoundments in HUC 0511 (green; right). .........................................75

Figure 45. Number and cumulative surface-area of impoundments by decade 

and by HUC-2 since 1900. .........................................................................................................75

Figure 46. Average annual evaporation from NID impoundments.......................................76

Figure 47. Average-annual potential evaporation from impoundments, by decade...........77

Figure 48. Percentage of average-annual potential evaporation from HUC-4s 

relative to decadal average-annual rainfall by decade...........................................................78

Figure 49. Percent change in maximum-daily precipitation-weighted water yield 

for all HUC-4s (top left) and for HUC-4s with statistically significant trends only 

(top right). Change for All HUC-4s (bottom), with significant trends shown in blue. ...........80

Figure 50. Consumptive water use in the conterminous United States (from 

Moore et al. 2015).......................................................................................................................81

Figure 51. Percent change in winter precipitation-weighted water yield for all HUC4s (top left) and for HUC-4s with statistically significant trends only (top right). 

Change for all HUC-4s (bottom), with significant trends shown in blue. ..............................83

Figure 52. Percent change in spring precipitation-weighted water yield for all HUC4s (top left) and for HUC-4s with statistically significant trends only (top right). 

Change for all HUC-4s (bottom), with significant trends shown in blue. ..............................84

Figure 53. Percent change in summer precipitation-weighted water yield for all 

HUC-4s (top left) and for HUC-4s with statistically significant trends only (top 

right). Change for all HUC-4s (bottom), with significant trends shown in blue....................85

Figure 54. Percent change in fall precipitation-weighted water yield for all HUC-4s 

(top left) and for HUC-4s with statistically significant trends only (top right). 

Change for all HUC-4s (bottom), with significant trends shown in blue. ..............................86

Figure 55. Seasonal estimates of consumptive water use (from Moore et al.

2015).............................................................................................................................................88

Figure 56. Change in annual streamflow at index stations with significant trends 

over the past century...................................................................................................................92

Figure 57. Change in maximum-daily streamflow at index stations with 

significant trends. ........................................................................................................................93

Figure 58. Change in winter streamflow at index stations with significant trends.............94

Figure 59. Change in spring streamflow at index stations with significant trends.............94

Figure 60. Change in summer streamflow at index stations with significant 

trends. ...........................................................................................................................................95
MRG&P Report No. 34 viii

Figure 61. Change in fall streamflow at index stations with significant trends...................95

Figure 62. Change in annual total and annual average streamflow at major index 

stations..........................................................................................................................................97

Figure 63. Change in maximum daily streamflow at major index stations..........................99

Figure 64. Change in seasonal streamflow at major index stations. ................................ 100

Figure 65. Change in maximum winter streamflows at major index stations.................. 101

Figure 66. Change in maximum spring streamflows at major index stations..................102

Figure 67. Change in maximum summer streamflows at major index stations. .............103

Figure 68. Change in maximum fall streamflows at major index stations. ...................... 104

Figure 69. Median drainage area-weighted Q1.5 by HUC-4. ................................................ 107

Figure 70. Median drainage area-weighted Q10 by HUC-4.................................................. 107

Figure 71. Median drainage area-weighted Q100 by HUC-4................................................. 108

Figure 72. Median suspended-sediment yield at the Q1.5 by sub-region (HUC-4). .......... 110

Figure 73. Suspended-sediment load at the Q1.5 for the earliest decade of data at 

sediment index stations (see Table J-2 for dates)................................................................ 111

Figure 74. Sediment load at the Q1.5 for the latest decade of data at sediment 

index stations (see Table J-2 for dates).................................................................................. 111

Figure 75. Change in suspended-sediment load at the Q1.5 at sediment index 

stations, expressed as a percent. Blank areas represent a lack of index stations. ........112

Figure 76. Change in suspended-sediment load at the Q1.5 at sediment index 

stations, Expressed in tonnes per day. Blank areas represent a lack of index 

stations....................................................................................................................................... 113

Figure 77. Frequency distribution of changes in suspended-sediment load at the

Q1.5 from sub-regions at sediment index stations. ............................................................... 114

Figure 78. Frequency distribution of annual suspended-sediment yields for all 

sub-regions (HUC-4s) in the Mississippi River Basin. .......................................................... 115

Figure 79. Median annual sediment yield by gage.............................................................. 116

Figure 80. Average annual suspended-sediment yield by HUC-4 from gage 

medians. .................................................................................................................................... 117

Figure 81. Changes in median-annual suspended-sediment yields over the period 

of record by HUC-4.................................................................................................................... 118

Figure 82. Trends in annual sediment delivery to the Lower Mississippi at major 

index stations using decadal transport curves (see Table 5 for details)........................... 121

Figure 83. Decline in average annual delivery of suspended-sediment to the 

LMR.............................................................................................................................................122

Figure D-1. Average January evaporation from NID impoundments. ................................ 142

Figure D-2. Average February evaporation from NID impoundments. .............................. 142

Figure D-3. Average March evaporation from NID impoundments.................................... 143

Figure D-4. Average April evaporation from NID impoundments. ...................................... 143

Figure D-5. Average May evaporation from NID impoundments........................................144

Figure D-6. Average June evaporation from NID impoundments.......................................144

Figure D-7. Average July evaporation from NID impoundments......................................... 145
MRG&P Report No. 34 ix

Figure D-8. Average August evaporation from NID impoundments................................... 145

Figure D-9. Average September evaporation from NID impoundments. .......................... 146

Figure D-10. Average October evaporation from NID impoundments............................... 146

Figure D-11. Average November evaporation from NID impoundments. ..........................147

Figure D-12. Average December evaporation from NID impoundments. ..........................147

Tables

Table 1. HUC-4s in the Mississippi River Basin. ........................................................................8

Table 2. HUC-4s with greater than 5% of potential evaporation relative to annual 

rainfall............................................................................................................................................78

Table 3. Changes and percent contributions in discharge between 1930 and 

2014 from the major (HUC-2) index stations as derived from the linear 

regressions of annual data.........................................................................................................98

Table 4. Decadal average annual sediment delivery to the Lower Mississippi................119

Table 5. Trends in annual sediment delivery to the Lower Mississippi at major 

index stations using decadal transport curves.....................................................................120

Table A-1. Timeframe for precipitation analysis by HUC-4. .................................................132

Table B-1. Timeframe for water-yield analysis by HUC-4. ....................................................134

Table B-2. Timeframe for precipitation-weighted water yield analysis by HUC-4. ............135

Table B-3. Index stations selected for calculating suspended-sediment yields at 

the Q1.5 for sub-regions. ........................................................................................................... 136

Table C-1. Number and size of NID impoundments used in this study.............................139

Table E-1. Change in annual rainfall by HUC-4. .................................................................... 148

Table E-2. Change in maximum annual daily rainfall by HUC-4. ........................................ 151

Table E-3. Change in maximum annual 7-day rainfall total by HUC-4. ..............................154

Table E-4. Change in winter rainfall by HUC-4....................................................................... 157

Table E-5. Change in spring rainfall by HUC-4....................................................................... 160

Table E-6. Change in summer rainfall by HUC-4................................................................... 163

Table E-7. Change in fall rainfall by HUC-4............................................................................. 166

Table E-8. Change in maximum daily winter rainfall by HUC-4........................................... 169

Table E-9. Change in maximum daily spring rainfall by HUC-4........................................... 172

Table E-10. Change in maximum daily summer rainfall by HUC-4..................................... 175

Table E-11. Change in maximum daily fall rainfall by HUC-4.............................................. 178

Table E-12. Change in maximum 7-day fall rainfall by HUC-4. ........................................... 181

Table F-1. Change in annual water yield by HUC-4...............................................................184

Table F-2. Change in maximum annual daily water yield by HUC-4................................... 187

Table F-3. Change in maximum annual 7-day water yield totals by HUC-4.......................190

Table F-4. Change in winter water yield by HUC-4. ...............................................................193

Table F-5. Change in spring water yield by HUC-4................................................................196

Table F-6. Change in summer water yield by HUC-4. ...........................................................199
MRG&P Report No. 34 x

Table F-7. Change in fall water yield by HUC-4......................................................................202

Table F-8. Change in maximum daily spring water yield by HUC-4. ...................................205

Table F-9. Change in maximum daily summer water yield by HUC-4. ...............................208

Table F-10. Change in maximum daily fall water yield by HUC-4........................................ 211

Table G-1. Change in annual precipitation-weighted water yield by HUC-4. ..................... 214

Table G-2. Change in maximum annual daily precipitation-weighted water yield 

by HUC-4. ....................................................................................................................................217

Table G-3. Change in winter precipitation-weighted water yield by HUC-4........................220

Table G-4. Change in spring precipitation-weighted water yield by HUC-4........................223

Table G-5. Change in summer precipitation-weighted water yield by HUC-4....................226

Table G-6. Change in fall precipitation-weighted water yield by HUC-4.............................229

Table H-1. Change in annual streamflow at index stations with significant trends.........232

Table H-2. Change in maximum annual daily streamflow at index stations with 

significant trends. .....................................................................................................................238

Table H-3. Change in winter streamflow at index stations with significant trends. .........244

Table H-4. Change in spring streamflow at index stations with significant trends. .........250

Table H-5. Change in summer streamflow at index stations with significant 

trends. ........................................................................................................................................255

Table H-6. Change in fall streamflow at index stations with significant trends................261

Table I-1. Median drainage area-weighted peak discharge (water yield) 

(m3/s/km2) by HUC-4 for all recurrence intervals. ...............................................................268

Table J-1. Median suspended-sediment yield at the Q1.5 for each HUC-4 along 

with the number of gages and standard error.......................................................................271

Table J-2. Suspended-sediment load at the Q1.5 showing changes between the 

first and latest decades of data collection at sediment index stations. Shaded 

rows denote the downstream-most stations for each region (HUC-2). ............................. 273

Table J-3. Median and average annual suspended-sediment loads by HUC-4.................276

Table J-4. Summary of changes in median annual suspended-sediment yields 

within each HUC-4 for the period of record........................................................................... 279
MRG&P Report No. 34 xi

Preface

This study was conducted for the US Army Corps of Engineers (USACE) as 

part of the Mississippi River Geomorphology and Potamology (MRG&P) 

Program, under Project 127672; "Mississippi River Geomorphology and 

Potamology Program." The MRG&P is part of the Mississippi River and 

Tributaries Project and is managed by the USACE, Mississippi Valley 

Division (MVD), and districts. At the time of publication of this report, the 

MRG&P Program Director was Dr. James W. Lewis. The MVD 

Commander was MG R. Mark Toy. The MVD Director of Programs was 

Mr. Edward E. Belk.

The work was performed by Cardno, Oxford, MS, and the Department of 

Geography and Environment; University of Southampton; Highfield, 

Southampton UK.

The work was performed under the direction of the River and Estuaries 

Engineering Branch of the Flood and Storm Protection Division, US Army 

Engineer Research and Development Center, Coastal and Hydraulics 

Laboratory (ERDC-CHL).

At the time of publication of this report, Mr. David. P. May was Chief of 

the River and Estuaries Engineering Branch; Dr. Cary Talbot was Chief of 

the Flood and Storm Protection Division. The Deputy Director of ERDCCHL was Mr. Jeffrey R. Eckstein, and the Director was Dr. Ty V. Wamsley.

The Commander of ERDC was COL Teresa A. Schlosser, and the Director 

was Dr. David W. Pittman.
MRG&P Report No. 34 1

1 Introduction

Background

River management and channel-improvement operations on the

Mississippi River are focused on three primary goals: maintaining a 

navigation channel, flood control, and preservation and restoration of its 

environmental resources (e.g., fish and wildlife habitats). In recent years, 

significant hydrologic events have affected the Mississippi River Basin. 

During the 2011 flood, the peak discharge at Vicksburg was approximately 

65,000 cubic meters per second (m3/s) (2.3 million cubic feet per second 

[ft3/s]),1 which eclipsed the 1927 flood. Historic flood levels were observed 

along the Mississippi River again in late 2015. At Cape Girardeau, 

Missouri, flood levels rose above the record crest of the Great Flood of 

1993. At St. Louis, Missouri, flood levels were at a record third highest 

after the 1973 and 1993 floods, respectively.

Flood protection on the Lower Mississippi River (LMR), below where it 

merges with the Ohio River near Cairo, Illinois, is a major focus of the 

Mississippi Valley Division (MVD), U.S. Army Corps of Engineers 

(USACE). An important component of this objective is understanding how 

peak-streamflow discharges for the LMR have changed with time.

Changes in hydrological conditions have been occurring in the 

Mississippi River Basin and the rest of the United States for a long time 

and certainly longer than the period of available data. For this study, the 

start of the data collection and beginning of the analysis is quite variable 

but typically coincides with the turn of the twentieth century. Hydrologic 

changes that affect discharges to the LMR are a result of changes in 

precipitation and rainfall-runoff relations that play a role in the 

magnitude and frequency of hydrologic events. Contributing to shifting 

hydrologic patterns are human-induced changes to the natural 

environment such as agriculture, urbanization, channelization, and dam 

construction. The latter affects annual, maximum-daily streamflows in 

 

1 For a full list of the spelled-out forms of the units of measure used in this document, please refer to 

U.S. Government Publishing Office Style Manual, 31st ed. (Washington, DC: U.S. Government 

Publishing Office, 2016), 248-52, https://www.govinfo.gov/content/pkg/GPO-STYLEMANUAL2016/pdf/GPO-STYLEMANUAL-2016.pdf.
MRG&P Report No. 34 2

every region of the United States but most severely in the Great Plains 

and Southwest (Fitzhugh and Vogel 2011).

Numerous studies have shown the significance of recent changes in 

extreme weather events and their impact on peak flows, low-flows, and 

flooding, etc. Many of the previous studies on trends and variability of 

precipitation and streamflow have focused on the latter half of the 

twentieth century over the conterminous United States (e.g., McCabe and 

Wolock 2002; Sagarika et al. 2014) although Qian et al. (2007) did focus 

on the Mississippi River Basin. In general, precipitation during that time 

frame increased (e.g., Pryor and Schoof 2008; de Martino et al. 2013); 

droughts have become shorter and less frequent, except in the interior of 

the West (Andreadis and Lettenmaier 2006); pan evaporation decreased 

(Peterson et al. 1995) while evapotranspiration increased (Szilagyi et al. 

2001) from May-October; and annual and monthly moderate-to-low 

streamflows increased (e.g., Lettenmaier et al. 1994; Lins and Slack 1999; 

Douglas et al. 2000).

Average, annual increases in precipitation during the period 1982–2011 as 

compared to 1901–2011 range from 3.7% for the Red River Basin above 

Alexandria to 6.6% for the Upper Mississippi River above Grafton, 

Illinois1. Peak streamflows, however, are the result of peak rainfall or 

extreme events. This unpublished report by B. Frederick1 also shows 

important increases in heavy-precipitation events (2-day events in excess 

of the 5-year recurrence interval) since the 1970s with a sharp increase in 

the 1990s while Kunkel et al. (2013) show the increase to begin the 1960s 

and similarly jump in the 1990s. Some of the most pronounced increases 

in heavy rainfall events (more than 30% above the long-term average) 

have occurred in parts of the Mississippi River Basin encompassed by the 

upper Midwestern states east of a north-south line defined by Kansas, 

Nebraska, and the Dakotas (Karl et al. 2009).

It seems however, that discharge increased more in the Mississippi River 

Basin than increased precipitation alone could explain (Raymond et al.

2008; Zhang and Schilling 2006). Zhang and Schilling (2006) cited landuse changes as a leading cause of increased baseflow and overall 

streamflow along the Mississippi River since the 1940s. Schilling et al.

 

1 B. Frederick, National Weather Service, personal communication, 2018.
MRG&P Report No. 34 3

(2010) extended that analysis by examining the relationship between 

streamflow and soybean acreage in the Upper Mississippi Basin.

Other important factors to high streamflow include hurricane landfalls 

along the Atlantic and Gulf coasts. Some of the most devastating floods of 

the twentieth century have been related to hurricane landfall (Barlow 

2011). Hurricane season in the Atlantic is considered to be June 1 to 

November 30, with hurricane-related precipitation peaking during midAugust through early October (Larson et al. 2005). In September, the 

hurricane-related portion of monthly precipitation reaches a maximum of 

up to 15 percent along the Gulf and East Coasts (Larson et al. 2005). 

Hurricane-related precipitation is therefore likely to impact streamflows in 

the Mississippi River Basin, especially during the fall season and when 

hurricane tracks cross into the interior of the continent.

Imposed changes in flow regime through anthropogenic and natural 

factors, as well as changes in basin characteristics, result in adjustments to 

sediment loads and sediment delivery. Both the fine (silt and clay) and 

coarse (sand and gravel) fractions are important. This is because the fine 

fraction is generally transported farther downstream, has the ability to 

transport adsorbed constituents, and can cause downstream water-quality 

problems. The coarse fraction is important because it is hydraulically 

controlled, is limited by the transport capacity of the flow, and provides 

sediment for downstream deposition. Many of the changes in sediment 

load have involved significant channel erosion in alluvial systems, 

deposition behind dams, and in many cases has led to the evolution of 

entire channel systems. Thus, the magnitude and temporal and spatial loci 

of sediment production and delivery may have changed over the last 

century from the uplands and fields to the channel systems. As such, this 

study aims to support the MVD mission by determining how hydrologic 

variables such as precipitation, streamflow, and sediment contributions 

have changed over the past century across the Mississippi River Basin.

Objectives

The primary objectives of this work were to compile and interpret data on 

precipitation, flow and suspended-sediment transport over the period of 

record for the entire Mississippi River Basin, and to detect and determine 

regional variations and changes over time and space. In keeping with this 

overall purpose, the project aimed to evaluate temporal changes in the 

delivery of water and suspended sediment from the LMR’s major tributary 
MRG&P Report No. 34 4

rivers and how those changes contributed to changes in flow and sediment 

discharge in the LMR. Temporal changes and spatial differences in the 

production of runoff (flow) and sediment at smaller, sub-regional scales 

were of particular interest to help identify regional patterns.

Approach

The approach used in this study is entirely empirical. That is, to use 

available, raw data (collected by United States Government agencies) 

representing important aspects of the hydrologic cycle and suspendedsediment transport to interpret spatial and temporal variability and 

changes across the Mississippi River Basin. As such, there is no numerical 

modeling or modeling data relied on in this study. A benefit of this 

approach is that any uncertainty related to model algorithms and 

associated predictions from watershed or climate simulations does not 

influence interpretations of the data included herein.

To undertake such a large-scale effort, a massive data mining and analysis 

approach, coupled with a logical hydro-geographic framework, was 

required. A similar approach, using Level-III Ecoregions as differentiators 

of regional hydrology and sediment-transport characteristics, was used to 

investigate regional differences in the 1.5-year flow (Q1.5) and suspendedsediment sediment yields Simon et al. (2004) and by Simon and Klimetz 

(2010). The Level-III Ecoregion framework is a preferred method of the 

U.S. Environmental Protection Agency. This system groups areas of 

similar geology, soils, vegetation, climate, wildlife, land use, and hydrology 

(Omernik 1995; Omernik and Griffith 2014). Within the continental 

United States, there are 105 Level-III ecoregions, with the Mississippi 

River Basin encompassing 41 of these ecoregions.

Results of ongoing research on trends in annual precipitation conducted 

by MVD are in general agreement with the findings of Simon and Klimetz 

(2010), showing a moderate increase in precipitation across the region. 

Recently, Rice et al. (2016) examined streamflow over the continental 

United States from 1940 to 2009 using a frequency domain method and 

summarizing results at the scale of Level-II Ecoregions. However, since 

the objectives of this study focus on the delivery of water and sediment as 

well as flood protection and conveyance, a drainage basin approach was 

deemed more appropriate, and the concept of hydrologic units was 

adopted. Further, these previous efforts were geographically based, 
MRG&P Report No. 34 5

focusing on determining regional differences and not change with respect 

to time as this current study is.

Data mining and analyses were conducted in the context of using a range 

of hydrologic metrics that could be used to enhance knowledge of spatial 

and temporal trends to inform river managers charged with flood 

protection. As described in the following paragraphs, this required the use 

of a range of spatial scales and parameterizing aspects of hydrology 

(precipitation and discharge) related to the production of peak flows.

The data employed in this study and the associated analysis relies on 

fundamental hydrologic data that are presented in logical order as might 

occur on the landscape:

1. rainfall being supplied to the landscape

2. runoff production (flow or stream discharge)

3. evaporation from impoundments

4. production of suspended sediment.

Thus, this report starts with an analysis of precipitation across the basin, 

looking at a range of metrics to characterize magnitude and distribution. 

These include annual and seasonal totals as well as maximums over a 

range of durations. Discharge is evaluated in terms of absolute values from 

the downstream-most stations and as a water yield (per unit drainage 

area) and as a water yield per unit precipitation for all stations. These flow 

metrics are again analyzed as average-annual and seasonal values, as well 

as peak discharges and yields over a range of durations (1 to 7 days).

Evaporation is evaluated on an annual basis from impoundments within 

selected regional areas (defined below).

Finally, sediment production and yields (loads per unit area) are 

investigated using metrics related to average, annual values distributed 

across the basin and as loads at the Q1.5. Less suspended-sediment data are 

available than for either precipitation or discharge limiting analysis of 

temporal trends to decadal rends and overall changes.

Spatial divisions

The continental United States is divided into 18 major drainage basins or 

hydrologic units by the U.S. Geological Survey (USGS) and further 

subdivided into sub-regions, accounting units, and cataloging units. Each 
MRG&P Report No. 34 6

hydrologic unit is identified by a hydrologic unit code (HUC) that consists 

of 2 to 14 digits based on the level of classification. Smaller HUCs 

represent larger regions while larger unit HUCs represent respective 

smaller sub-regions and cataloging units that are nested within the 

regional HUC. For example, the largest sub-basins such as the Ohio and 

Missouri Rivers are cataloged as HUC-2s. Boundaries of a HUC are 

defined by topographic as well as hydrographic criteria that delineate an 

area upstream of a river, stream or similar surface waters. In addition to 

precipitation falling directly on a HUC, a HUC can accept surface water 

directly from upstream drainage areas. 

The LMR receives flow and materials from its major tributary basins 

including the following (Figure 1):

• HUC-02: Upper Mississippi River

• HUC-05: Ohio River

• HUC-06: Tennessee River

• HUC-10: Missouri River

• HUC-11: Arkansas, White, and Red Rivers.

Other, smaller tributaries such as the Yazoo River drain directly to the 

LMR. 

To better understand the temporal and spatial distribution of hydrologic 

and sediment contributions to the LMR, results are summarized at the 

regional (HUC-2) and sub-regional (HUC-4) levels, of which there are 84 

in the Mississippi River Basin (Figure 1; Table 1). The geographic location

of an individual gage determines its associated HUC-4, regardless of the 

size of the drainage area. For example, both the Mississippi River gage at 

Vicksburg, Mississippi (USGS 07289000), with a drainage area of 2.95 

million square kilometers (km2), and Clear Creek in Oxford, Mississippi

(USGS 07271000), with a drainage area of 26.7 km2, fall into HUC 0803, 

the Lower Mississippi-Yazoo. 
MRG&P Report No. 34 7

Figure 1. Major hydrologic regions (2-digit hydrologic unit codes) and sub-regions 

(4-digit hydrologic unit codes) of the Mississippi River Basin. 

Sub-regional results of streamflow in this study are presented as water 

yields to make comparisons of streams of different drainage areas 

appropriate. Traditionally, water yield was used in forestry and 

agricultural settings to describe the amount of runoff generated per unit 

area, per unit time as a depth (e.g., Hibbert 1969; McMinn and Hewlett 

1975; Bosch and Hewlett 1982; Hornbeck et al. 1993). For example, 

Stednick (1996) summarized results of watershed studies in the Central 

Plains that suggest 100% harvesting of a forested watershed resulted in 

306–752 millimeter (mm) increases in annual water yield. Here, water 

yield is presented in units of m3/s/km2 so that data from basins of 

different sizes can be readily combined to obtain a value for a larger 

region (e.g., a HUC). Once water yields are generated for a given flow 

parameter (i.e., peak value, annual value), median values representative 

of the HUC-4 are computed as long as there are three or more gages 

within a given HUC-4 for a given year (or season). Years or seasons of a 

given year with fewer than three gages (for that period) were excluded 

from sub-regional analyses.
MRG&P Report No. 34 8

Table 1. HUC-4s in the Mississippi River Basin. 

HUC-4 HUC-4 Name HUC-4 HUC-4 Name 

0501 Allegheny 1003 Missouri-Marias

0502 Monongahela 1004 Missouri-Musselshell

0503 Upper Ohio 1005 Milk

0504 Muskingum 1006 Missouri-Poplar

0505 Kanawha 1007 Upper Yellowstone

0506 Scioto 1008 Big Horn

0507 Big Sandy-Guyandotte 1009 Powder-Tongue

0508 Great Miami 1010 Lower Yellowstone

0509 Middle Ohio 1011 Missouri-Little Missouri

0510 Kentucky-Licking 1012 Cheyenne

0511 Green 1013 Missouri-Oahe

0512 Wabash 1014 Missouri-White

0513 Cumberland 1015 Niobrara

0514 Lower Ohio 1016 James

0601 Upper Tennessee 1017 Missouri-Big Sioux

0602 Middle Tennessee-Hiwassee 1018 North Platte

0603 Middle Tennessee-Elk 1019 South Platte

0604 Lower Tennessee 1020 Platte

0701 Mississippi Headwaters 1021 Loup

0702 Minnesota 1022 Elkhorn

0703 St. Croix 1023 Missouri-Little Sioux

0704 Upper Mississippi-Black-Root 1024 Missouri-Nishnabotna

0705 Chippewa 1025 Republican

0706 Upper Mississippi-Maquoketa-Plum 1026 Smoky Hill

0707 Wisconsin 1027 Kansas

0708 Upper Mississippi-Iowa-Skunk-Wapsipinicon 1028 Chariton-Grand

0709 Rock 1029 Gasconade-Osage

0710 Des Moines 1030 Lower Missouri

0711 Upper Mississippi-Salt 1101 Upper White

0712 Upper Illinois 1102 Upper Arkansas

0713 Lower Illinois 1103 Middle Arkansas

0714 Upper Mississippi-Kaskaskia-Meramec 1104 Upper Cimarron

0801 Lower Mississippi-Hatchie 1105 Lower Cimarron

0802 Lower Mississippi-St. Francis 1106 Arkansas-Keystone

0803 Lower Mississippi-Yazoo 1107 Neosho-Verdigris

0804 Lower Red-Ouachita 1108 Upper Canadian

0805 Boeuf-Tensas 1109 Lower Canadian

0806 Lower Mississippi-Big Black 1110 North Canadian

0807 Lower Mississippi-Lake Maurepas 1111 Lower Arkansas

0808 Louisiana Coastal 1112 Red Headwaters

0809 Lower Mississippi 1113 Red-Washita

1002 Missouri Headwaters 1114 Red-Sulphur
MRG&P Report No. 34 9

Temporal divisions

Temporal variability was evaluated over the entire period of record as the 

difference between conditions at the beginning and end of the recorded 

period (i.e., 1900-present). Throughout this investigation, a variety of 

temporal scales were used to parameterize the hydrologic data, ranging 

from instantaneous peaks for the outlets of the major HUC-2 basins to 

annual values of water yield. Throughout this study, calendar years were 

used. Seasonal trends are an important metric for river management to 

identify precipitation and associated changes in flow throughout a year. 

The four seasons are defined as follows:

• Winter: December (from previous year) – February

• Spring: March – May

• Summer: June – August

• Autumn: September – November.

Given that this study is also focused on peak-flow values and how they 

relate to discharges in the LMR, maximum flow rates over 1, 3, 5, and 7

days were also investigated. Focus is given to the 1-day and 7-day totals. 

Insight into the general timing of annual peak discharges is obtained from 

analysis of seasonal extreme discharges.
MRG&P Report No. 34 10

2 Data Requirements, Sources, and 

Availability

Daily precipitation data

The fundamental data unit for precipitation that was available for this 

study was daily climate data, some dating back to the mid- to late-1800s 

and available through the Global Historical Climatology Network-Daily 

(GHCND). These were accessed online through the National Oceanic 

Atmospheric Administration (NOAA) National Climatic Data Center. The 

entire GHCND database was downloaded, and data for all stations within 

the study area were extracted for the parameter PRCP (precipitation). 

Figure 2 shows the location of the 6,815 GHCND precipitation gages with 

at least one complete calendar year of data that were used in this study. 

(Additional information on the GHCND database and its contents are 

available online at http://www1.ncdc.noaa.gov/pub/ data/ghcn/daily/ghcnd-stations.txt). A 

complete list of GHCND gages used in this study can be found in 

Appendix A.

Figure 2. Location of GHCND precipitation gages used in this study. 
MRG&P Report No. 34 11

Mean-daily streamflow and peak-annual streamflow

Mean-daily discharge data were obtained through batch downloads using 

the U.S. Geological Survey (USGS) Water Services Tool 

(https://waterservices.usgs.gov/rest/DV-Test-Tool.html). There are 6,186 flow stations with 

at least one complete calendar year of data within the study area (Figure 3). 

For the majority of these gages, the drainage or contributing area to the 

gage is published. Where drainage areas were not defined, areas were 

estimated using either the USGS online tool, StreamStats version 4 Beta 

Application (https://streamstatsags.cr.usgs.gov/streamstats/) or for smaller basins, 

delineating the basin area using a geographic information system (GIS). 

Additional mean-daily discharge data at gages along the Mississippi River 

main stem were obtained through the USACE River Gages website 

(http://rivergages.mvr.usace.army.mil/ WaterControl/new/layout.cfm). 

Instantaneous, peak-annual discharge data are available at 8,210 USGS 

gages. However, only 7,118 gages have at least 10 annual observations, 

which was considered the minimum number required for flood frequency 

analysis (Figure 4). (A complete list of USGS gages used in this study can 

be found in Appendix B.)

Figure 3. Location of USGS mean-daily streamflow gages used in this study. 
MRG&P Report No. 34 12

Figure 4. Location of USGS peak-streamflow gages used in this study. 

Suspended-sediment concentrations

To analyze the spatial distribution of suspended-sediment loads and to 

investigate how these have changed with time, it was decided to use the 

raw concentration and associated discharge data from the time of 

sampling. Discrete suspended-sediment concentration with corresponding 

instantaneous flow data was obtained using the USGS Sediment Data 

Portal (https://cida.usgs.gov/sediment/). Within the study area, there are 1,638 

gages with at least 10 samples (Figure 5), which was considered the 

absolute minimum number required for generating sediment transportrating relations. Figure 5 shows location of all sediment stations used in

this study. (See Appendix B for a complete list of USGS sediment stations 

used in this study.)
MRG&P Report No. 34 13

Figure 5. Location of USGS suspended-sediment stations used in this study. 

National inventory of dams

Information on the location, characteristics, and construction date of 

dams is important to the investigation both in terms of understanding 

changes in flow regimes at particular gages and in determining their role 

in trends in evaporation and water yield. These data were obtained from 

the USACE National Inventory of Dams (NID). Within the study area there 

are 13,629 impoundments listed in the NID database with published 

completion dates and data on the surface area of impounded water. This 

excludes privately owned dams and only considers dams owned by the 

federal, state, or local government(s) as well as those owned by public 

utilities or whose ownership type is not listed. The impoundments (at 

normal pool) from the dams in this database and used in this study range 

in size from the Lake Afton Dam in Kansas at 0.00004 km2 (KS02553) to 

Bull Shoals in Arkansas, at 1,839 km2 (AR00160). (A list of the number 

and size of NID impoundments used in this study within each HUC-4 can 

be found in Appendix C.)

Daily pan-evaporation observations

To achieve a better understanding of the role of impoundments in altering 

hydrology and water availability, evaporation data were required across 
MRG&P Report No. 34 14

the basin. In addition to precipitation data, the GHCND database contains 

Class A pan-evaporation observations stored under the parameter EVAP.

Pan evaporation is an empirical measurement of evaporation, which is a 

function of temperature, wind, humidity, and solar radiation. This 

parameter can be used to estimate evaporation from open bodies of water 

(WMO 1966; Farnsworth and Thompson 1982). Unlike GHCND 

precipitation data, pan-evaporation data from the entire continental 

United States were used, with 830 gages having sufficient data for this 

study (Figure 6). (The GHCND pan-evaporation gages used in this study 

can be found in Table A1 in Appendix A.)

Figure 6. Location of GHCND pan evaporation gages used in this study. 

Geospatial data

Additional sources of geospatial data were obtained from the U.S. 

Department of Agriculture, Natural Resources Conservation Service

(NRCS) Geospatial Data Gateway (https://datagateway.nrcs.usda.gov/). This 

included delineations of HUC-2s and HUC-4s from the USGS Watershed 

Boundary Dataset as well as 1:24,000 hydrography networks. All spatial 

data presented in this study are projected using the Albers equal-area 

conic projection, USGS version. 
MRG&P Report No. 34 15

3 Methodology

Precipitation analysis

To evaluate changes for a variety of precipitation metrics, only GHCND 

gages within the study area with complete calendar years of data were 

used in the analysis. For each complete year of record, annual totals and 

maximum values (1-day, 3-day, etc.), and seasonal totals and their 

respective maximum values were computed as discussed in the earlier 

section Geospatial and Temporal Context. For a given year or season, if 

there were three or more gages with data within the HUC-4, a median 

precipitation value was calculated and included in the analysis. A 

minimum of 30 (non-continuous) annual or seasonal values were required 

for trend analysis. Table A-1 in Appendix A lists the minimum, maximum, 

and total number of years with three or more usable precipitation gages.

Evidence of changes in the frequency and intensity of hurricanes that 

impact the Gulf and east coasts of the United States provided impetus to 

investigate their influence on precipitation trends and patterns in parts of 

the Mississippi River Basin. Barlow (2011) examined the influence of 

hurricanes in the continental United States during the period 1975–1999 

and demonstrated that the impact of hurricanes extends well beyond 

coastal areas and into the mid-continent. During this 25-year period, the 

Gulf Region experienced the greatest number of days with heavy 

precipitation exceeding 101.6 mm (4 inches [in.]). The percentage of these 

days in the Gulf Region that were associated with hurricanes, however, 

ranged from 67% to less than 33%. Along the east coast and up into the 

Ohio River Basin, the percentage of heavy precipitation days associated 

with hurricanes was often greater than 67%.

Hurricane-related rainfalls were estimated following the methodology 

outlined in Darby et al. (2013, 2016) using the NOAA International Best 

Track Archive for Climate Stewardship (IBTrACS) database (version 

v03r02) (Knapp et al. 2010; available online: https://www.ncdc.noaa.gov /ibtracs/). 

IBTrACS was used to locate the paths of all recorded hurricanes (at daily 

time-steps) intersecting or passing near the Mississippi Basin for the 

available period of record, 1950–2014 (Figure 7). The IBTrACS data 

comprise six hourly best-track positions and intensity estimates. Only 

storms designated as being in a tropical phase with 1-minute maximum,
MRG&P Report No. 34 16

sustained surface-wind speeds exceeding 34 knots (17.5 m/s) are included 

in the analysis.

Figure 7. Hurricane tracks affecting the Mississippi River Basin (1950–2014). 

Rainfall anomalies associated with these storm paths were defined by first 

interpolating, using the nearest neighbor, daily rainfall values observed at 

a network of 151 precipitation stations across the Mississippi River Basin 

onto a 0.1° (∼11 km2) resolution grid. Next, all rainfall stations located 

within a 500 km search radius (Rodgers et al. 2000; Englehart and 

Douglas 2001) from the centroid of the storm on that date were identified. 

These identified stations were then temporarily (for the specific time-step) 

removed from the analysis, and an updated rainfall surface (minus the 

identified stations) was re-interpolated onto the same 0.1° grid. A rainfall 

anomaly surface, representing estimated rainfall associated with the 

identified storm and time-step, was then obtained by differencing the 

original and updated surfaces. This process was repeated for each daily 

time-step, allowing the observed rainfall series at each meteorological 

station to be adjusted by subtracting rainfall anomalies within the grid 

square specific to each gage from the observed daily rainfall totals. 

Trend analysis of hurricane-related rainfall anomalies was conducted at a 

given GHCND gage if it was impacted by hurricanes during 10 or more 

non-sequential years. In addition to examining annual-total and annual-
MRG&P Report No. 34 17

maximum total trends, trends in the total number of days of hurricane 

anomaly and maximum number of consecutive days of anomaly were 

investigated.

Streamflow analysis

To evaluate changes in absolute values of water discharge (not water yield) 

provided at the outlets of each HUC-4 and particularly the HUC-2’s, 

trends in streamflow (in m3/s) were examined at select index stations. 

These stations were chosen based on their location along the major rivers 

or tributaries, period of record, and approximate drainage area. Where 

drainage area was approximately equal to the drainage area of its 

encompassing HUC-4 or if smaller, the first upstream gage with an 

adequate record was selected. Approximately 400 gages where chosen to 

represent regional (HUC-2) and sub-regional (HUC-4) changes in 

streamflow (Figure 8). Annual streamflow and seasonal streamflows were 

computed as the sum of the mean-daily flows in each period. 

Several of the index stations represent the major HUC-2 basins draining to 

the LMR and include the Missouri River at Hermann, Missouri (USGS 

06934500), Ohio River at Metropolis, Illinois (USGS 03611500), and the 

Mississippi River at Thebes, Illinois (USGS 07022000). In general, the 

relative contributions of streamflow to the Mississippi River from its major 

rivers and tributaries are well known. The majority of the streamflow to 

the LMR (~60%) originates in the Ohio River Basin. Contributions from 

the Upper Mississippi River (including the Illinois River) was computed as 

the difference between flows at Thebes, Illinois, and Hermann, Missouri. 

The USACE gage at Hickman, Kentucky (MS113D), was chosen to 

represent the flows at the upstream boundary of the LMR just below the 

confluence with the Ohio River. Meanwhile, flows at the USACE gage at 

Tarbert Landing, Louisiana (01100Q), were used to represent flows along 

the LMR, downstream of the confluence with the Arkansas River and the 

Old River Control Complex. 
MRG&P Report No. 34 18

Figure 8. Location of streamflow index stations. 

Calculation of water yield and precipitation-weighted water yield

Water yield, the amount of runoff (or discharge) per unit drainage area, is 

a convenient metric to compare stations of different sizes providing a 

measure of runoff production for a given area. Temporal trends in water 

yield reflect hydrologic changes resulting from the combined effects of 

changing precipitation regimes as well as landscape and direct changes 

imposed by humans. 

As with precipitation, a minimum of three gages were needed to determine 

annual or seasonal values of water yield for a given HUC-4, and a 

minimum of 30 non-continuous years of median values were required for 

trend analysis. All HUCs, except HUC-0809, had sufficient data for 

analyses of water yield. Data collection at many of these gages started 

approximately at the beginning of the twentieth century, providing a 100-

year record of flows. Another large group of stations were initiated in the 

1930s. The timeframe for the water-yield analysis for each HUC-4, based 

on the period of record of the gages contained within their boundaries, is 

summarized in Table B-1 in Appendix B. 
MRG&P Report No. 34 19

To reveal the level of anthropogenic effects on changes in discharge and 

runoff production and potentially, sediment yields, water yield was 

normalized (divided) by total annual precipitation, thus removing the 

influence of altered precipitation regimes. Since precipitation-weighted 

water yield relies on coupled observations of flow and precipitation, the 

timeframe for analysis is slightly different from the separate precipitation 

and water-yield analyses. These are listed in Table B-2 in Appendix B. 

Trend analyses

Temporal changes over the period of available data within each HUC-4 

were assessed using statistical analyses of monotonic trends. Such 

analyses provide an indication of the magnitude and direction of changes 

at specific stations that, when taken collectively, can explain net changes at 

the HUC-4 scale. More importantly, this analysis provides evidence as to 

whether computed trends are reliable (statistically significant).

Monotonic trends (increases or decreases without reversals) of annual and 

seasonal data were determined using the Kendall tau test at a significance 

level (p-value) of 0.05. The Kendall tau trend test is a non-parametric test 

based on Kendall’s tau statistic (Kendall 1975) with a continuity correction 

and was implemented using the statistical package R using the function 

kendallTrendTest in the package EnvStats (Millard 2013). It is a common 

metric utilized by the USGS to assess trends in water quality (Hirsch et al.

1982; Hirsch and Slack 1984) and is suitable for detecting trends in 

hydrological time series, which are typically skewed and contain outliers. 

In the test, the null hypothesis is that tau is equal to zero while the 

alternative hypothesis is that the true tau is not equal to zero, where 

positive values of tau indicate an increasing monotonic trend and negative 

values indicate a decreasing trend. The test statistic itself is z, and the pvalue of z allows the user to accept or reject the null hypothesis.

To quantify the magnitude and rate of change over the period of record, a 

robust linear regression was fit through the data, and the difference 

between the first and last years of record were estimated from the linear 

fit. This procedure was selected rather than simply taking the difference 

between the first and last points, one of which could potentially be an 

outlier. The robust linear regression (function rlm) was implemented 

using the R library MASS (Venables and Ripley 2002). For example, 

annual streamflow for the Mississippi River at St. Louis, Missouri,

significantly increased (p < 0.05) between 1863 and 2013 by 
MRG&P Report No. 34 20

approximately 438,000 m3/s based on the linear trend shown in red 

(Figure 9).

Figure 9. Annual streamflow along the Mississippi River at St. Louis, Missouri. 

Peak-streamflow analysis

To obtain an understanding of the spatial distribution of instantaneous 

peak flows, frequency statistics for gages with greater than 10 annual-peak 

observations were batch calculated using a program written in R. For 

quality assurance, the program was first made to replicate results from the 

Excel workbook FreqCurves_ver306.xlsm (available online: 

http://go.usa.gov/KS6). This was developed by the NRCS Water Quality and 

Quantity Technology Development Team, which reproduced the results 

from Bulletin 17b, Guidelines for Determining Flood Flow Frequency

(Interagency Advisory Committee on Water Data 1981). 

Flows at the 1.5-, 5-, 10-, 25-, 50-, and 100-year recurrence intervals were 

computed for each gage using the entire period of record. Once frequency 

estimates were computed for all gages, results were normalized by 

drainage area then summarized by HUC-4.

Annual-evaporation rates

To provide a simple evaluation of the role of dams on water losses due to 

evaporation, an investigation was carried out to combine information on 

the total surface area impounded at normal pool with available data on 

evaporation rates. There are 791 GHCND stations in the continental 

United States with sufficient pan evaporation data (see Appendix A). Note
MRG&P Report No. 34 21

that gages within the Mississippi River Basin are assigned a 4-digit HUC;

elsewhere, the HUC-4 is listed as “NA.” The methodology used was based 

on the original methodology of Farnsworth et al. (1982) (TR-34). Months 

with fewer than 20 observations were excluded from the analysis. 

Individual monthly sums were computed by multiplying the daily average 

evaporation by the number of days in the month. Monthly evaporation 

means were computed for months with greater than 5 years of record.

In TR-34, annual average evaporation totals were computed as the sum of 

the individual monthly means. However, in this study, the focus was 

estimation of evaporation from NID impoundments. As such, kriging with 

maximum GHCND EVAP values was used to estimate monthly evaporation 

averages at each NID impoundment. Annual average evaporation totals 

were then summed from the individual monthly evaporation estimates. 

Average annual evaporation volumes were then computed by multiplying 

the published surface area by the evaporation rate.

Annual evaporation volumes at the HUC-4 level were computed by 

summation of the cumulative evaporation volume for all NID 

impoundments within the HUC. For simplicity, it was assumed that the 

annual evaporation volume at each impoundment was static over time and 

would count towards the total evaporation volume from the HUC after the 

published year of completion.

Assuming pan evaporation is a perfect estimator of potential evaporation, 

inferences about actual evapotranspiration can be made by the following:

 EEEE = 22 WW − EEpp (1) 

where:

ETW = wet-surface evapotranspiration

Ep = potential evaporation.

Determination of annual suspended-sediment yields

Annual suspended-sediment yields at the sub-regional (HUC-4) level were 

determined using two separate methods. The first method involved 

calculating the suspended-sediment yield at a discharge that could be used 

to compare with other sites and that represented a meaningful geomorphic 

condition. The discharge selected for this purpose was the Q1.5, a flow rate 

that is commonly used to represent the “effective discharge” (Leopold et al.
MRG&P Report No. 34 22

1964; Dunne and Leopold 1978; Williams 1978; Castro and Jackson 2001; 

Simon et al. 2004). Of course, there can be substantial variability around 

this average value (Williams 1978), but it has been shown to be a good 

measure of this parameter for ecoregions across the United States (Simon 

et al. 2004). To calculate representative sediment yields at the Q1.5 for each 

sub region (HUC-4), the following procedure was used:

• Select an index station for each of the HUC-4 sub-regions representing 

the most downstream site with an extensive data set

• Develop a first-approximation sediment-transport rating using a single 

power function from instantaneous discharge and concentration data 

• Solve the resulting sediment-transport relation using the Q1.5 for that 

station

• Divide by drainage area to obtain a suspended-sediment yield in 

tonnes per year per square kilometer (t/y/km2).

Using a constant value of flow frequency allowed direct comparison 

between sites and sub-regions as well as investigating how suspendedsediment yield had varied at a single site (sub-region) over time. The 

earliest sampled decade for index stations representing the HUC-4s is the 

1930s. Many regions do not have sufficient sampling to determine 

temporal trends until the 1970s. A list of these stations and their 

applicable decades is provided in Table B4 in Appendix B.

The sediment station in each HUC-4 with the greatest drainage area, 

greatest number of suspended-sediment samples, and longest period of 

record was selected at the representative index station. Transport ratings 

were developed for each decade of available data to determine whether the 

transport ratings were shifting (changing) with time. Examples from the 

Arkansas and Missouri Rivers are shown in Figure 10. The change in 

sediment load can be easily visualized by noting where the black vertical line 

(representing the Q1.5) crosses each regression line. Using results from only 

the first and last decades of suspended-sediment observation, load (and 

yield) at the Q1.5 was computed to quantify net change over the period. If a 

sediment station did not have a calculated Q1.5 value from the peak-flow 

analysis at the same gage, the Q1.5 was estimated based on a relation 

between drainage area and Q1.5 for gages within the corresponding HUC-4.

The second method was aimed at providing mean-annual suspendedsediment loads and yields for each sub-region to obtain a spatial 
MRG&P Report No. 34 23

distribution of sediment contributions across the basin. In this case, 

suspended-sediment transport ratings were developed for every sediment 

station in the database. Instead of automatically accepting the firstapproximation rating relation based on a single power function, every 

relation was visually inspected to determine if in fact, a more accurate 

representation of the general relation between flow and concentration 

could be attained using several linear segments (in log-log space). Where 

necessary, the rating relations were adjusted using one or more additional 

segments. For sediment stations with associated mean-daily flows 

(minimum of one complete year), daily sediment loads were calculated. 

These values were then summed for each year to obtain annual loads, 

divided by the number of years to obtain an average, and then divided by 

drainage area to obtain average, annual sediment yield for each station. To 

then characterize suspended-sediment yields at the HUC-4 level, the 

median value from all of the stations in the sub-region was reported.

The data set of sampled suspended-sediment concentrations at each 

station was considered sufficient if there was a minimum of 10 

observations and if the maximum sampled flow was at least 75% of the 

calculated or estimated Q1.5.
MRG&P Report No. 34 24

Figure 10. Examples of decadal shifts in sediment-transport ratings (including 

equations) from index stations along the Arkansas (top) and Missouri Rivers (bottom). 

The vertical black line represents the Q1.5. 

y = 8.6929x1.6196

R2 = 0.8529

y = 0.9766x1.8197

R2 = 0.9206

y = 1.0421x1.7557

R2 = 0.9462

y = 0.3119x1.8519

R2 = 0.7923

y = 1.1852x1.3712

R2 = 0.8576

y = 0.6353x1.2875

R2 = 0.832

y = 1.0305x1.3481

R2 = 0.8171

1

10

100

1000

10000

100000

1000000

10000000

0.1 1.0 10.0 100.0 1000.0 10000.0

SEDIMENT LOAD, IN TONNES, PER DAY

FLOW, IN CUBIC METERS PER SECOND

1930s

1940s

1950s

1960s

1970s

1980s

1990s

Q1.5

HUC-1111

Arkansas River at Tulsa, OK (07164500)

y = 0.4495x1.822

R2 = 0.7101

y = 0.6444x1.7839

R2 = 0.7654

y = 0.0003x2.5495

R2 = 0.8814

y = 0.005x2.0951

R2 = 0.525

y = 0.003x2.1966

R2 = 0.7919

y = 0.0006x2.3764

R2 = 0.8222

y = 0.0009x2.305

R2 = 0.8652

1000

10000

100000

1000000

10000000

100 1000 10000

SEDIMENT LOAD, IN TONNES PER DAY

FLOW, IN CUBIC METERS PER SECOND

1940s

1950s

1970s

1980s

1990s

2000s

2010s

Q1.5

HUC-1030

Missouri River at Hermann, MO (06934500)
MRG&P Report No. 34 25

4 Results and Discussion

Precipitation trends

Annual trends

Results show that over the past century there have been important 

increases in average annual precipitation across the Mississippi River 

Basin. Statistically significant trends of increasing precipitation (at the 

0.05 level) are typically in the order of 10%–25% (Figure 11, top right), 

ranging from 53.6 to 232 mm more annual rainfall now than a century 

ago. In fact, much of the Mississippi River Basin is experiencing more 

rainfall now than it did 100 years ago. Figure 11 (top left) shows this very 

clearly, with only a few HUC4s, mostly on the western margins of the basin 

indicating decreases. Because of the strict requirements in denoting 

statistically significant trends at the p<0.05 level, fewer HUC4s are 

identified in Figure 11 (top right), but still, all but one show increases. As a 

cautionary note in interpreting this and similar figures to follow is that the 

map represents changes expressed in percent while the bar charts show 

the absolute values of the changes, in millimeters, over the approximate 

100-year time period. 

A statistically significant decrease in annual precipitation was observed 

only in HUC-1002, the Missouri Headwaters, which showed a reduction of 

10%–25% or 77 mm. The greatest increases in annual precipitation (25%–

50%) were observed in HUCs 0703 (St. Croix), 1109 (Lower Canadian), 

and 1112 (Red River Headwaters), where the average-annual increase was 

~165 mm per year.

Large swaths of sub-regions comprising the Upper Mississippi, the 

Tennessee and the Lower Mississippi Basin show relatively large increases 

in annual precipitation, in excess of 150 mm (approximately 6 in.). Large 

percentage increases in annual precipitation for some sub-regions in the 

Missouri Basin represent increases of generally less than 100 mm. 

Previous studies have also noted statistically significant increases in 

annual precipitation totals in South Dakota, Nebraska (de Martino et al.

2013), and Kansas (de Martino et al. 2013; Rahmani et al. 2016). Studies 

of national scope that quote average increases of 4%–5% across the 

contiguous United States show greater increases in large parts of the 

Lower Missouri and Upper Mississippi River Basins (Karl et al. 2009; 
MRG&P Report No. 34 26

Walsh et al. 2014)1. As a reminder, this current study uses a different 

methodology to define change over time, which is a linear regression 

between the earliest and the latest available data. Most of the other studies 

that are cited here compare differences in two average values, one being 

some recent period and the other being either the period of record (e.g.,

1901–2015) or an earlier period. 

Peak annual trends

With most of the Mississippi River Basin experiencing more rainfall than it 

did 100 years ago, it is particularly germane to evaluate how peak rainfall 

totals may have changed over the period. Given the enormous size of the 

basin, it was not just the 24-hour peak values that were of interest but the 

total maximum rainfall amounts over periods of up to 7 days. These results 

approximate the change in intensity and duration of maximum, annual 

rainfall events. Only results for the 1- and 7-day peaks are displayed in the 

report maps in an effort to conserve space. In general, it was found that on 

an annual basis, peak rainfall amounts have increased across the basin 

with the exception of some western areas of the basin including the upper 

Platte, upper Cimarron, the Republican, and the upper Arkansas River 

Basins (Figure 12–13).

Although much of the basin displays increases in peak precipitation totals, 

statistically significant trends in maximum, daily (24-hour) precipitation 

totals are less common. These increases range 10%–25% and 25–50%, or 

6.9 mm in HUC 0708 (Upper Mississippi-Iowa-Skunk-Wapsipinicon) to 

24.5 mm in HUC 0807 (Lower Mississippi-Lake Maurepas) (Figure 12).

Increases in 7-day total (Figure 13) were also typically on the order of 10%–

25% and 25%–50%. HUC 0807 had the greatest magnitude of increases in 

daily, 3-day (366 mm), 5-day (388 mm), and 7-day (416 mm) precipitation 

totals. Other sub-regions along the LMR also showed some of the largest 

increases in peak-rainfall amounts. The increases in the 7-day peak

precipitation values are particularly important in the context of potential 

increases in runoff in the larger basins as they occur over broad areas.

These increases are corroborated by an earlier study from Groisman et al.

(2012) who focused on patterns of moderately heavy (12.7–25.4 mm/day), 

heavy (25.4–76.2 mm/day), and very heavy (76.2–155 mm/day), and 

extreme (> 155 mm/day) precipitation events in the central United States. 

 

1 B. Frederick, National Weather Service, personal communication, 2018.
MRG&P Report No. 34 27

Their results showed (1) no change in moderately heavy events, (2)

increases in the frequency of heavy events, and (3) a pronounced increase 

(40%) in extreme precipitation events.

By themselves, these results indicate that inputs of precipitation have 

become more intense across much of the basin, particularly in the lower 

Mississippi along the Gulf Coast, but also in the Tennessee, lower 

Arkansas, lower Missouri and the upper Mississippi. Subsequent sections 

will focus on how these overall increases are distributed throughout the 

year and how they translate into changes in runoff production.
MRG&P Report No. 34 28

Figure 11. Percent change in annual rainfall for all HUC-4s (top left) and for HUC-4s with statistically significant trends only (top right). 

Change for all HUC-4s (bottom), with significant trends shown in blue. 

 

 
MRG&P Report No. 34 29

Figure 12. Percent change in maximum, annual 24-hour rainfall for all HUC-4s (top left) and for HUC-4s with statistically significant trends 

only (top right). Change for all HUC-4s (bottom), with significant trends shown in blue. 

 

 
MRG&P Report No. 34 30

Figure 13. Percent change in maximum, annual 7-day rainfall for all HUC-4s (top left) and for HUC-4s with statistically significant trends only 

(top right). Change for all HUC-4s (bottom), with significant trends shown in blue. 

 

 
MRG&P Report No. 34 31

Seasonal trends

Changes in seasonal precipitation identify shifts in the timing of 

hydrologic inputs and influences partitioning of rainfall into runoff, 

evapotranspiration, and/or infiltration. This in turn may have important 

implications for water availability and irrigation, flood control, power 

generation, and overall river management. Groisman et al. (2001) 

reported significant increases of 7%–15% in area-weighted, mean 

precipitation during the spring, summer, and fall across the continental 

United States for the period 1910–1996. No changes were shown during 

winter. Within the Mississippi River Basin, data1 show that the largest 

average, recent (1982–2011) seasonal increases have occurred during the 

fall (8.9%), from 7.8% above the Missouri River at Hermann to 11.4% 

above the Ohio River at Metropolis. Average increases in spring 

precipitation above some of the major gauging stations were the second 

greatest for this period, at 4.1%. 

Results using non-weighted point observations from the GHCND in this 

study identified changes in seasonal precipitation that are in general 

agreement with those cited above. The most dramatic changes (increases) 

have taken place during the spring and particularly the fall. The changes 

are summarized as follows: 

• Winter: Moderate increases in the upper Mississippi and Tennessee 

Basins, decreases in the Ohio, and little change in the Missouri 

(Figure 14)

• Spring: Moderate increases across the entire basin with the exception 

of the Red River Basin and upstream areas of the Arkansas River 

(Figure 15)

• Summer: Small decreases throughout the Missouri and Tennessee 

Basins, small increases in the Ohio, and moderate increases in the 

Upper Mississippi, Arkansas, and Red River Basins (Figure 16)

• Fall: Dramatic increases (up to approximately 150 mm) are shown 

south and east of a line extending from south-central Oklahoma to 

southwestern New York. This area includes much of the Ohio River 

Basin, the Tennessee River, the LMR, and the lower Arkansas and Red 

River Basins (Figure 17). The spatial distribution of these increases is 

similar to those shown by B. Frederick1. Further, much of these 

 

1 B. Frederick, National Weather Service, personal communication, 2018.
MRG&P Report No. 34 32

increases may be related to changes in hurricane characteristics in this 

region over the past century.

Statistically significant trends in winter precipitation were identified in the 

Arkansas (1102) and Missouri headwater areas (HUCs 1002, 1003, 1005) 

(Figure 14). Significant trends in spring precipitation were detected in 

parts of all HUC-2s except the Lower Mississippi (Figure 15). Significant 

increasing trends in fall precipitation were detected throughout much of 

the southern and eastern parts of the study area (Figure 17). During the 

summer, precipitation increased in northern Colorado (HUC-1019) and in 

parts of the Midwest while decreasing in HUCs 0505 (Kanawha) and 1101 

(Upper White) (Figure 16).
MRG&P Report No. 34 33

Figure 14. Percent change in winter rainfall for all HUC-4s (top left) and for HUC-4s with statistically significant trends only (top right). Change 

for all HUC-4s (bottom), with significant trends shown in blue. 

 

 
MRG&P Report No. 34 34

Figure 15. Percent change in spring rainfall for all HUC-4s (top left) and for HUC-4s with statistically significant trends only (top right). Change 

for all HUC-4s (bottom), with significant trends shown in blue. 

 

 
MRG&P Report No. 34 35

Figure 16. Percent change in summer rainfall for all HUC-4s (top left) and for HUC-4s with statistically significant trends only (top right). 

Change for all HUC-4s (bottom), with significant trends shown in blue. 

 

 
MRG&P Report No. 34 36

Figure 17. Percent change in fall rainfall for all HUC-4s (top left) and for HUC-4s with statistically significant trends only (top right). Change for 

all HUC-4s (Bottom), with significant trends shown in blue. 

 

 
MRG&P Report No. 34 37

Peak seasonal trends

Winter trends

Results for trends in peak, winter precipitation showed a regional decline 

in daily (Figure 18), 3-day, and 5-day totals along the Rocky Mountains 

and across much of the Missouri River Basin. Some of these decreases as 

with the headwaters of the North Platte (HUC 1018) and Arkansas Rivers 

(HUC 1102) are statistically significant. The Missouri River headwaters 

(HUCs 1002, 1003, and 1005) also showed statistically significant declines 

in the 7-day winter totals. Small to moderate increases were detected 

through a broad area of the mid-continent, with significant increases in 

peak winter precipitation in HUCs 0701 (Mississippi Headwaters), 0601 

(Upper Tennessee), 0713 (Lower Illinois), and 1109 (Lower Canadian). 

Groisman et al. (2001) did not find significant changes in winter 

precipitation and in snow cover over the Upper Mississippi and Midwest 

over the last half of the twentieth century.

Spring trends

As with changes in total spring precipitation, peak spring precipitation 

also showed general increases across the entire basin. Daily increases of 5–

10 mm were typical in many sub-regions. The only statistically significant 

trends that were detected for all four time periods were positive. Changes 

in the maximum daily totals are shown in Figure 19. Maximum increases 

in multi-day, spring rainfall totals were in excess of 150 mm. Like total

spring precipitation, there were some sub-regions that indicated slight 

decreases, but these were distributed across the river basin.

Summer trends

Changes in peak summer precipitation show a general pattern of small 

decreases in the Missouri River Basin, the central-lower Mississippi (HUC 

0802), and the upper reaches of the Upper Mississippi. In general, all 

other regions showed mild increases (~ 5 mm). Because changes in 

summer peak rainfall were small, only a few HUCs showed significant 

trends in either direction for all of the durations. The 1-day distributions 

are shown in Figure 20.
MRG&P Report No. 34 38

Figure 18. Percent change in maximum daily winter rainfall for all HUC-4s (top left) and for HUC-4s with statistically significant trends only 

(top right). Change for all HUC-4s (bottom), with significant trends shown in blue. 

 

 
MRG&P Report No. 34 39

Figure 19. Percent change in maximum daily spring rainfall for all HUC-4s (top left) and for HUC-4s with statistically significant trends only 

(top right). Change for all HUC-4s (bottom), with significant trends shown in blue. 

 

 
MRG&P Report No. 34 40

Figure 20. Percent change in maximum summer daily rainfall for all HUC-4s (top left) and for HUC-4s with statistically significant trends only 

(top right). Change for all HUC-4s (bottom), with significant trends shown in blue. 

 

 
MRG&P Report No. 34 41

Fall trends

Some of the most drastic changes in precipitation over the past century 

have occurred in the fall across the southern and eastern parts of the 

basin. As with the increases in total fall precipitation, these sizeable 

increases in peak fall rainfall extend from the very southwestern part of 

the basin, northeast along the Appalachian Mountains, and areas south 

and east of there. One- and three-day peak rainfalls have increased, 

respectively, as follows:

• Tennessee River Basin: ~15 mm, ~200 mm

• LMR Basin: ~20-30 mm, ~100-400 mm

• Lower Arkansas River: ~15-20 mm; ~200-250

• Ohio River Basin: ~10-20 mm; ~100-200 mm.

These are important increases in peak precipitation totals, particularly for 

the 3-day duration, and indicate that storm events are getting more severe 

during this time of year in these parts of the basin. The implications are that 

corresponding runoff events will be larger as well. Further, the spatial 

distribution of these increases in peak fall precipitation again point towards 

an increased influence of hurricanes in peak-rainfall totals and hence, peak 

discharges in these sub-regions. The changes in peak rainfall are shown in 

Figure 21 for daily maximums and Figure 22 for 7-day maximums.

Additional details/results of the sub-regional precipitation analyses can be 

found in Appendix E.
MRG&P Report No. 34 42

Figure 21. Percent change in daily fall rainfall for all HUC-4s (top left) and for HUC-4s with statistically significant trends only (top right). 

Change for all HUC-4s (bottom), with significant trends shown in blue. 

 

 
MRG&P Report No. 34 43

Figure 22. Percent change in maximum 7-day fall rainfall for all HUC-4s (top left) and for HUC-4s with statistically significant trends only 

(top right). Change for all HUC-4s (bottom), with significant trends shown in blue. 

 

 
MRG&P Report No. 34 44

Hurricane-related precipitation trends

Hurricanes make landfall in the United States generally along the Gulf and 

Atlantic Coasts (Figure 7). Many hurricanes, particularly those that skirt 

the Atlantic Coast, do not impact the Mississippi River Basin. Those that 

make landfall along the Gulf Coast, however, impact sub-regions of the 

Mississippi River Basin as they start tracking north and northeast into the 

LMR Valley. Others track slightly farther to the east and do not cross into 

the Mississippi River Basin until they reach the Tennessee River Basin 

before heading out to sea. Fewer reach the basin traveling north-northeast 

across Texas, entering the basin in Oklahoma, Louisiana, and Arkansas. 

Hurricane-related precipitation can be extreme over short durations, 

producing annual-maximum values.

The Atlantic hurricane season is generally considered to span the period 

June 1 through November 30, although only 5 hurricanes (out of 294) 

have made landfall in the United States in November since 1951 (NOAA 

2019). The period when most hurricanes make landfall is August through 

October, with the peak month being September. Between 1951 and 2018, 

42% of the landfalls have occurred during the summer months while 58% 

have occurred during the fall (37% in September). This would indicate that 

hurricane-related precipitation would generally span summer and fall but 

on average, may be most pronounced in the fall.

Based on precipitation anomalies identified in the precipitation record, a

set of metrics were established to evaluate how the impact of hurricanes 

on precipitation totals has changed since 1950. These include the

following:

• number of continuous days of hurricane activity (per year)

• total number of days with hurricane activity (per year)

• total annual precipitation anomaly due to hurricanes

• maximum 1-day, 3-day, 5-day, and 7-day rainfall anomalies due to 

hurricanes.

In the series of figures that follow, precipitation gages with statistically 

significant trends in precipitation anomalies (p < 0.1) are shown as larger 

circles. Similar to the previous discussion and maps of trends in seasonal, 

particularly fall precipitation, a band of increased precipitation anomalies 

can be observed stretching southwest to northeast through the basin. 

Areas in the Ohio River Basin, especially along the Appalachians, are 
MRG&P Report No. 34 45

experiencing prolonged exposure to hurricanes (Figure 23 and Figure 24). 

Significant increases in duration are also observed in the Mississippi 

Delta. Still, a few gages with statistically significant decreases in the 

number of days and total duration of hurricane-related precipitation were 

also observed.

Figure 23. Changes in maximum annual, continuous days of hurricane anomaly. 
MRG&P Report No. 34 46

Figure 24. Changes in total annual days of hurricane anomaly. 

Shifting the focus from frequency and duration to actual changes in the 

amount of annual hurricane-related precipitation, important and 

statistically significant increases are apparent throughout the Lower 

Mississippi and Ohio River Basins (Figure 25). On average, these increases 

fall within the 0–125 mm class. A maximum recorded increase of 592 mm 

was detected at a gage in HUC 0809. Note that not all hurricane-related 

precipitation is captured by these GHCND gages. The numbers reflect the 

amount of anomaly recorded if a gage were continuously recording 

precipitation between 1950 and 2014, which is not the case for majority of 

the gages. Still, the spatial trend is for a general increase in hurricanerelated precipitation on an annual basis across the southeast and 

extending into the Ohio River Basin. This may help explain the calculated 

increases in fall total and peak precipitation in these regions.
MRG&P Report No. 34 47

Figure 25. Changes in annual hurricane anomaly. 

Expanded statistical significance of increases in hurricane-related 

precipitation is seen for peak-rainfall events ranging from 1 to 7 days 

(Figure 26–Figure 27). Multi-day increases of ~100–300 mm (since 1950) 

is typical at many of these gages with some significant values as high as 

~400–600 mm. The results of this analysis indicate that the hurricanes 

that are making landfall and impacting the Mississippi River Basin are, on 

average, producing more rainfall on both an annual basis and over 1- to 

7-day periods than they did in 1950.
MRG&P Report No. 34 48

Figure 26. Changes in maximum annual, daily hurricane anomaly. 

Figure 27. Changes in maximum annual, 7-day total hurricane anomaly. 

The spatial distribution of these changes seems to indicate a combination 

of effects related to general circulation patterns and a potential orographic 

effect from the Appalachian Mountains. Finally, there seems to be a 

curious lack of significant increases in hurricane-related duration or 

precipitation amounts in the region best described as along the northern 
MRG&P Report No. 34 49

Alabama border. It requires further investigation as to whether this 

perceived pattern is real and whether it is related to a similar combination 

of circulation and topographical conditions.

Summary of precipitation results

On an average annual basis, most of the Mississippi River Basin receives 

more rainfall than it did 100 years ago. Typical increases are in the range of 

10%–25%. The largest increases have occurred in the Upper and Lower 

Mississippi and the Tennessee River Basins and may exceed 150 mm 

(approximately 6 in.). Large percent increases in the Missouri River Basin 

represent increases of less than 100 mm (approximately 4 in.) per year. A 

few of the far-western HUC-4s show decreases in annual precipitation. Peak

annual rainfall totals over 1, 3, 5, and 7 days also show increases over most 

of the basin indicating that inputs of precipitation have become more 

intense.

On a seasonal basis, there were the following: 

• Dramatic and significant increases in seasonal precipitation during the 

fall, with up to 150 mm (approximately 6 in.) more rainfall in some 

HUC-4s. Statistically significant increases are recorded for HUC-4s 

south and east of a line extending from south-central Oklahoma to 

southwestern New York. This spatial pattern is similar to the changes 

(increases) identified in hurricane-related precipitation.

• Moderate increases during spring across the entire basin with 

decreases in the Red River and upstream areas of the Arkansas.

• Moderate increases during winter in the upper Mississippi and 

Tennessee, decreases in the Ohio, and little change in the Missouri.

• During summer, small decreases throughout the Missouri and 

Tennessee, small increases in the Ohio, and moderate increases in the 

Upper Mississippi, Arkansas and Red River Basins.

Seasonal peak precipitation mirrors the changes in total precipitation with 

the exception of important declines in peak winter precipitation in the 

Rockies and much of the Missouri Basin. The dramatic increases in fall 

precipitation along the Appalachians is reinforced by increases in peak 

values. Three-day totals increased by hundreds of millimeters. These 

results point to an increasing influence of hurricanes in the southeast and 

the Ohio River Basin. Hurricanes that are making landfall and impacting 
MRG&P Report No. 34 50

the Mississippi River Basin are, on average, producing more rainfall on 

both an annual basis and over 1- to 7-day periods than they did in 1950.

Water yield trends

Annual trends

Water yield is an expression of the generation of runoff per unit drainage 

area. Although precipitation represents the fundamental hydrologic input, 

discharge is the expression of that atmospheric input that is of particular 

interest to river managers. By using water yield as opposed to actual 

discharge, basins of different size and from different hydro-physiographic 

settings can be readily compared. This metric provides insight into how 

changes in precipitation along with anthropogenic activities have affected 

streamflows. Changes expressed as a percent are somewhat easier to 

understand for water yield than the absolute value because of the 

unfamiliarity in considering values comprised of these units (cubic 

meters/cubic kilometers). Later sections will focus specifically on the 

absolute value of discharges (expressed in cubic meters) emanating from 

index stations.

Results on an annual basis show important and consistent increases in 

water yield across most of the Central Lowland province of the Interior 

Plains (Figure 28). Sankarasubramanian et al. (2001) found that the 

regional sensitivity of streamflow to changes in precipitation is highest in 

this region. In part, this could be due to large-scale programs of 

channelization that provided for much more efficient conveyance of flows 

as well as construction of tile drains to improve drainage. Statistically 

significant increases were also identified in parts of the lower Ohio Basin. 

Previous studies have also documented significant increases in annual 

minimum 7-day flow (low flows) throughout the Ohio River Basin, the 

Upper Mississippi, and lower Missouri (e.g., Douglas et al. 2000; Ahn and 

Palmer 2015). These findings indicate that more water is being delivered 

on an annual basis to the upstream boundary of the LMR than previous.

In contrast, annual water yields emanating from the sub-regions in the 

western-most parts of the basin have seen marked declines. Given that 

many of these areas have seen increases in annual and peak rainfall 

amounts, these declines may be related to significant anthropogenic 

effects, particularly water withdrawals for irrigation. This is likely the case 

with the declines indicated for the sub-regions in southern Louisiana. 
MRG&P Report No. 34 51

Caution is encouraged when interpreting results for water yield for HUCs 

whose period of record begin during the “dust bowl” era of the 1930s (see 

Table B in Appendix B).

Although this research and others document significant increases in 

precipitation, lengthy dry periods have also been detected in the latter half 

of the twentieth century in the southwest (Groisman and Knight 2008). 

This plays a role in decreasing trends in annual water yields observed

across much of the Great Plains with the exception of HUCs 1012 

(Cheyenne) and 1015 (Niobrara).

Peak annual trends

Changes in peak annual water yield are a proxy for how peak annual flood 

flows have changed over the study period. For the longer duration metrics 

such as the 5- and 7-day totals, peak water yields might reflect multiple 

pulses of flood waves. Again, throughout much of the mid-continent, peak 

flows have increased. This is in keeping with the general increases in 

precipitation and the enhanced drainage conditions (channelization and 

tile drainage) imposed in these areas (Figure 29–Figure 30). Reductions in 

western peak flows are readily apparent, probably reflecting not only 

withdrawals for irrigation in the region but flow control by dams. In these 

semi-arid regions, peak flows represent a large part of the total annual 

water yields. The negative trends in peak water yields across all four 

durations have been associated to increases in temperature (Mauget 

2003), leading to overall declines in streamflow (Rood et al. 2005). It is 

also quite possible that changes in hydrologic regimes through dam 

operations that tend to suppress high flow magnitudes, water withdrawals 

for irrigation and greater evaporative losses are important factors in the 

decreasing peaks in the western HUCs.

This study uses many more gages in the central United States than those 

used by Groisman et al. (2001). Those authors concluded that only the 

eastern third of the country demonstrated correlation between the 

interannual/interdecadal variability of maximum-annual events of 

streamflow and precipitation. Here, results show that throughout the 

Midwest, streamflow and thus water yield have increased. Meanwhile, 

water yield in parts of the upper Ohio have decreased. Findings on annual, 

maximum water yields are consistent with those of Rahmani et al. (2016), 

who studied extreme precipitation and flooding in the central United 

States using data from 1890 to 2013.
MRG&P Report No. 34 52

Figure 28. Percent change in annual water yield (top left) and for HUC-4s with statistically significant trends only (top right). Change for all 

HUC-4s (Bottom), with significant trends shown in blue. 

 

 
MRG&P Report No. 34 53

Figure 29. Percent change in annual maximum-daily water yield for all HUC-4s (top left) and for HUC-4s with statistically significant trends 

only (top right). Change for all HUC-4s (bottom), with significant trends shown in blue. 

 

 
MRG&P Report No. 34 54

Figure 30. Percent change in 7-day maximum water yield for all HUC-4s (top left) and for HUC-4s with statistically significant trends only (top 

right). Change for all HUC-4s (bottom), with significant trends shown in blue. 

 

 
MRG&P Report No. 34 55

Seasonal trends

Seasonal changes in water yield over the past century reflect changes in 

seasonal precipitation and seasonally variable anthropogenic influences 

such as operation of impoundments and water withdrawals for irrigation. 

In general, the spatial distribution of seasonal water yields again shows the 

increased discharges in the mid-continent and the decreases in the 

western-most parts of the basin. Winter and fall tend to show the greatest 

areal extent of increases while irrigation withdrawals that peak during the 

summer months in large parts of the upper Missouri and upper Arkansas 

and Tennessee Basins have resulted in important decreases in summer 

water yields. Temperature increases and evaporative losses behind 

impoundments may also play a role in the decrease in summer yields.

Statistically significant decreases in winter water yield were found in 

several areas of the Great Plains and Southern Rockies (Figure 31). This 

could reflect decreases in snowfall totals. In HUC 1104 (Upper Cimarron), 

water yields were 0.o12 m3/s/km2 less than those observed 70 years ago, 

representing a decrease of greater than 100%. The greatest decrease in 

winter yields was in HUC 0805 (Beouf-Tensas), of nearly 1.0 m3/s/km2

since 1939. In other areas of the Great Plains and in parts of the Wyoming 

Basin, Northern Rockies, and Central Lowlands, winter water yields 

increased. Spring water yields (Figure 32) displayed somewhat similar 

regional trends with many of the western watersheds showing significant 

declines. Declining trends were also observed in Wisconsin (HUC 0707) 

and Middle Tennessee-Hiwassee (HUC 0602). In the Lower Missouri 

(HUC 1030), median water yields increased by 1.43 m3/s/km2. Declining 

trends in summer water yield dominated most of the Great Plains (Figure 

33). Water yields in parts of the Ohio River basin during the summer and 

fall (Figure 34) increased.
MRG&P Report No. 34 56

Figure 31. Percent change in winter water yield for all HUC-4s (top left) and for HUC-4s with statistically significant trends only (top right). 

Change for all HUC-4s (bottom), with significant trends shown in blue. 

 

 
MRG&P Report No. 34 57

Figure 32. Percent change in spring water yield for all HUC-4s (top left) and for HUC-4s with statistically significant trends only (top right). 

Change for all HUC-4s (bottom), with significant trends shown in blue. 

 

 
MRG&P Report No. 34 58

Figure 33. Percent change in summer water yield for all HUC-4s (top left) and for HUC-4s with statistically significant trends only (top right). 

Change for all HUC-4s (bottom), with significant trends shown in blue. 

 

 
MRG&P Report No. 34 59

Figure 34. Percent change in fall water yield for all HUC-4s (top left) and for HUC-4s with statistically significant trends only (top right). 

Change for all HUC-4s (bottom), with significant trends shown in blue. 

 

 
MRG&P report No. 34 60

Peak seasonal trends

Winter trends

Changes in maximum winter water yields are somewhat misleading for

areas such as the Missouri River Basin because the absolute values of the 

changes are so small. Some sizeable and statistically significant increases 

have occurred for the 1-day winter peak in parts of the Ohio, upper 

Mississippi, and lower Mississippi Basins. With increasing durations, more 

sub-regions within the Ohio Basin show decreases while small increases are 

detected in the Missouri Basin. In the West, a statistically significant 

reduction in the extent of snow cover has complicated the relation between 

heavy precipitation and streamflow (Groisman et al. 2001). In the Missouri 

River headwaters, snowmelt runoff is occurring earlier than 55 years ago 

(Moore et al. 2007). Although not addressed in this study, research suggests 

that the Great Plains and Southern Rockies have longer snow seasons, but 

annually, the entire United States has seen a widespread decrease in the 

total number of yearly snow days (Knowles 2015).

Spring trends

Changes in spring maximum daily (Figure 35) water yields are shown 

below. Spring peak flows in places such as the North Platte (HUC 1018) 

are strongly influenced by winter precipitation in the high-elevation parts 

of the watershed. Daniels (2007) found that in the North Platte, basinaveraged precipitation provided a reliable predictor of the annual peak 

flood and mean annual discharge. In general, peak spring water yields 

(high flows) decreased in the western-most half of the Mississippi River 

Basin and increased throughout the central and eastern parts. Of note is 

the large increase in HUC 1030, the sub-region that encompasses the 

mouth of the Missouri River. Another HUC-4 of note is the sizeable 

decrease along the Gulf Coast (HUC 0808), most likely due to withdrawals 

for irrigation.
MRG&P Report No. 34 61

Figure 35. Percent change in maximum-daily spring water yield for all HUC-4s (top left) and for HUC-4s with statistically significant trends 

only (top right). Change for all HUC-4s (bottom), with significant trends shown in blue. 

 

 
MRG&P Report No. 34 62

Summer trends

Most of the western half of the Mississippi River Basin, including the 

upstream parts of the Missouri, Arkansas, and Red River Basins, exhibit 

significant decreases in peak water yields during the summer. (Figure 36). 

Small, but significant increases in these peaks are detected in the Upper 

Mississippi Basin related possibly to increased peak rainfall and the more 

efficient conveyance of water during convective storms. Increases are also 

shown in parts of the Ohio Basin where moderate increases in peak

rainfall amounts have been shown. In magnitude, however, the greatest 

significant increases in water yield across all four of the durations was 

observed in the Lower Missouri River (HUC 1030).

Fall trends

Again, the typical spatial distribution of changes in peak water yields 

across the basin are observed, with significant increases across the Ohio, 

Tennessee, and Lower Mississippi Basins and more moderate increases in 

the upper Mississippi Basin. These patterns are similar for all of the 

durations investigated and are displayed for the maximum daily duration 

only (Figure 37).

Changes within the Missouri Basin become more pronounced as duration 

increases from 1 day to 7 days but maintains a pattern where there are 

decreases in fall peaks in the upstream parts of the system combined with 

increases in the downstream parts. This culminates with the largest 

increases within the Missouri Basin in HUC 1030. Decreasing peak yields 

are seen throughout the western sub-basins of the Arkansas and Red 

Rivers. Significant decreasing trends were also observed in two of these 

western watersheds: HUC 1104 (Upper Cimarron) and 1109 (Lower 

Canadian). Despite these decreasing yields, water yield in the most 

downstream sub-regions of the Arkansas River system (HUC 1111; Lower 

Arkansas), like its neighbor in the Missouri River, was observed to have 

significantly increased on the order of >100% across all durations. 

Peak water yields during the fall season were all observed to significantly 

increase over the period of record from the Lower Missouri (1030), Lower 

Ohio (0514), and Upper Mississippi (0714) to the LMR (Figure 38). 
MRG&P Report No. 34 63

Figure 36. Percent change in maximum-daily summer water yield for all HUC-4s (top left) and for HUC-4s with statistically significant trends 

only (top right). Change for all HUC-4s (bottom), with significant trends shown in blue. 

 

 
MRG&P Report No. 34 64

Figure 37. Percent change in maximum-daily fall water yield for all HUC-4s (top left) and for HUC-4s with statistically significant trends only 

(top right). Change for all HUC-4s (bottom), with significant trends shown in blue. 

 

 
MRG&P Report No. 34 65

Figure 38. Maximum fall 7-day total water yield for select HUC-4s. 

Additional details/results of the sub-regional water yield analyses, 

including results not shown here, can be found in Appendix F.

Summary of water-yield results

Changes in water yield reflect how discharge regimes have changed over 

the past century and represent a combination of changes in precipitation 

and anthropogenic influences. Thus, the spatial patterns are somewhat 

different than those for precipitation alone.
MRG&P Report No. 34 66

Average-annual changes in water yield show stark spatial differences 

between the central part of the basin where important increases have 

occurred (particularly in the upper Mississippi) and the contributing 

western basins (upper Missouri, Arkansas and Red River Basins, as well as 

the western floodplains of the lower Mississippi), which show large 

percentage decreases in flow. Increases and decreases in these respective 

regions can be substantial, in the range of 25%–50% or even 50%–100%. 

Similar spatial trends and magnitudes are apparent for the 1-day and 

7-day peak water yields, reflecting vast changes in runoff generation and 

transmission through the river systems. The importance of water 

withdrawals and flow regulation in causing decreasing water yields is 

supported by the knowledge that this has occurred in some HUC4s that 

have experienced increases in precipitation.

The spatial distribution of changes in seasonal water yields again shows 

the increase in discharges throughout the mid-continent and the 

decreases in the western-most parts of the basin. Winter and fall tend to 

show the greatest areal extent of increases while irrigation withdrawals 

that peak during the summer months in large parts of the upper Missouri 

and upper Arkansas and Tennessee Basins, have resulted in important 

decreases in summer water yields and the amount of water available for 

ecological processes.

With regard to peak seasonal water yields, there again are stark spatial 

differences between the western regions showing decreases across the 1- to 

7-day durations, and the central and eastern regions that generally 

showing increasing peak yields. This clear geographic difference is 

probably mostly related to differences in how human requirements for 

water vary spatially across the basin relative to the availability of water 

while recalling that precipitation increases are larger in the mid-continent 

and southeastern parts of the basin, particularly in the fall. The fact 

remains though that peak annual and peak seasonal flows have 

dramatically increased in the central and eastern parts of the basin. This 

has implications for channel erosion and flood control.

Discussion of the temporal changes in the amount of water being delivered

to the LMR from the individual HUC-4s and its major HUC-2 tributaries is 

the subject of a subsequent section on contributions from index stations.
MRG&P Report No. 34 67

Trends in precipitation-weighted water yield

Annual trends

Changes in the magnitude and timing of precipitation are not the only 

influences on water yield. Land-use changes and anthropogenic activities 

can play an important role in determining how hydrologic inputs such as 

rain and snow are converted to runoff. Activities that impact hydrologic 

processes such as infiltration and evapotranspiration can modify rainfallrunoff relations and hence, discharge and water yields. Some of the 

anthropogenic activities that can have major impacts on rainfall-runoff 

relations include the change of forests and grasslands to agriculture, 

urbanization, dams and regulation of flows, evaporation from reservoirs, 

water withdrawals for irrigation, channelization, tile drainage, etc.

By normalizing the water yield data by the amount of precipitation for the 

given period that is being investigated, the role of human activities can be 

isolated. This metric is termed water-yield, per-unit precipitation, or 

precipitation-weighted water yield. Results indicate, therefore, the 

magnitude of the human-induced changes in water yield across the basin.

The floodplain in the lower Mississippi is water stressed due to large 

amounts of irrigation-water use associated with domestic and livestock 

consumptive-water use (Figure 39). Research by Moore et al. (2015) shows 

similar results associated with water scarcity, the ratio between 

consumptive water use and runoff. Areas such as the Mississippi River Plain 

begin relatively unstressed in the winter and become more stressed as 

irrigation increases and precipitation patterns change throughout the year.

Krakauer and Fung (2008) analyzed streamflow anomalies over the 

continental United States and found that streamflow increased in the late 

1960s with increased precipitation but has not increased since that time. 

Their analysis was based off of three distinct time periods: 1945–1965, 

1970–1990, and 1995–2005. McCabe and Wolock (2002) also detected the 

increase in streamflows around 1970. Results of this study indicate 

otherwise. McCabe and Wolock (2014) did note that the increase in 

streamflows did not extend beyond the year 2000.

Despite trends of increasing annual precipitation (Figure 11), in the central 

parts of the Mississippi River Basin, normalized, annual water yield still 

shows statistically significant increases in yield remain (Figure 39). This 
MRG&P Report No. 34 68

indicates that human activities are exacerbating this increase in annual 

water yield. For instance, in HUC-0712 (Upper Illinois), significant 

increases in all annual totals of precipitation, water yield, and 

precipitation-normalized water yield were observed (Figure 40). 

Presenting the data in this fashion provides a clear picture of the roles of 

precipitation and human-induced effects as one moves down the figure 

from trends in precipitation, to see the changes in hydrologic inputs, to 

water yield to see how that translates to changes in flow and finally, to 

precipitation weighted water yield, which isolates the anthropogenic 

effects. In this case, the increases in streamflow met and/or exceeded 

increases in precipitation and therefore indicates that much of the change 

can be attributed to human activities.

Other areas with significant increasing trends include the following 

HUC-4s: 0506 (Scioto), 0512 (Wabash), 0701 (Mississippi Headwaters), 

0704 (Upper Mississippi-Black-Root), 0706 (Upper MississippiMaquoketa-Plum), 0708 (Upper Mississippi-Iowa-Skunk-Wapsipinicon), 

0713 (Lower Illinois), 1015 (Niobrara), 1023 (Missouri-Little Sioux), and 

1111 (Lower Arkansas).

More moderate decreasing trends (but not statistically significant) are 

shown along all the headwater HUC-4s comprising the Ohio and 

Tennessee River Basins (Figure 39). Decreasing trends are also shown for 

the HUC-4s along the Gulf Coast and western floodplain of the LMR,

further attesting to the role of water withdrawals here on suppressing 

water yields in the region.

Figure 41 and Figure 42 are provided to show other examples of trends in 

precipitation that are opposite to trends in water yield due to 

anthropogenic activities. This is borne out by the trend in precipitationweighted water yield. Interestingly, HUCs 1002 (Missouri Headwaters) 

and 1112 (Red Headwaters) exhibited significant changes in precipitation 

and water yield that trend in opposite directions. HUC 1002 received 

77.4 mm less rainfall (-25% to -10%) but observed water yields on the 

order of 25% to 50% and > 100% higher, respectively (Figure 41). 

Meanwhile, despite increasing precipitation (129 mm or 25% to 50%), 

HUC 1112 yielded much less water, -100% to -50% and -50% to -25%, 

respectively (Figure 42). These are examples of the role of human activities

on streamflow.
MRG&P Report No. 34 69

In HUCs 0514 (Lower Ohio) and 0703 (St. Croix), annual precipitation 

and water yield significantly increased. However, when normalized by 

annual precipitation, water yield was not found to be statistically 

significant. The opposite was true for HUC 1109 (Lower Canadian). It 

received significantly more rainfall (25% to 50%) over the period of record 

but did not exhibit any detectable trends in water yield. When normalized 

by annual precipitation, water yield in HUC 1109 was found to be 

significantly negative, decreasing by a magnitude of -100% to -50%. 

Human-induced impacts have resulted in decreases in water yields in 

upstream reaches of the Missouri and Arkansas River Basins. The large 

decrease in precipitation-weighted water yield in HUC 1009 (PowderTongue) is heavily influenced by a single observation prior to the dust 

bowl era of the 1930s (Figure 43).
MRG&P Report No. 34 70

Figure 39. Percent change in annual precipitation-weighted water yield for all HUC-4s (top left) and for HUC-4s with statistically significant 

trends only (top right). Change for all HUC-4s (bottom), with significant trends shown in blue. 

 

 
MRG&P Report No. 34 71

Figure 40. Annual trends in HUC 0712 (Upper Illinois). 

Precipitation (top), water yield (middle), and precipitationweighted water yield (bottom). 
MRG&P Report No. 34 72

Figure 41. Annual trends in HUC1002 (Missouri Headwaters). 

Precipitation (top), water yield (middle), and precipitationweighted water yield (bottom). 
MRG&P Report No. 34 73

Figure 42. Annual trends in HUC1112 (Red Headwaters). 

Precipitation (top), water yield (middle), and precipitationweighted water yield (bottom). 
MRG&P Report No. 34 74

Figure 43. Precipitation-weighted water yield in HUC1009 

(Powder-Tongue). 

Potential evaporation from NID impoundments

Aside from water withdrawals from rivers and reservoirs for irrigation, 

evaporation from impoundments can potentially be another important 

source of water losses. As these losses represent the influence of dams 

throughout the basin, the NID database was used to determine the 

location and timing of dam construction and areal dimension of the 

associated pools on a decadal basis starting in 1900. The objective was to 

estimate evaporation behind dams as the product of the surface area of the 

impoundment and the rate of evaporation per unit area. Thus, changes in 

total potential evaporation behind dams over the past century is largely a 

function of (1) the timing and cumulative pool area of constructed dams 

and (2) the spatial distribution of pan-evaporation rates.

Examples of the number of dams constructed by decade in the state of 

Iowa is shown in Figure 44 (Left) along with the cumulative surface area 

impounded by dams in HUC 0511 (Right). Integrating the NID data across 

the major HUC-2 basins shows the major era of dam building between the 

1950s to 1970s, leading to current levels of impoundment and therefore, 

maximum levels of evaporation from these regions (Figure 45). 
MRG&P Report No. 34 75

Figure 44. NID impoundments in Iowa by completion date (left) and cumulative 

surface area of NID impoundments in HUC 0511 (green; right). 

Figure 45. Number and cumulative surface-area of impoundments by decade and by 

HUC-2 since 1900. 
MRG&P Report No. 34 76

Average annual potential evaporation at NID impoundments across the 

Mississippi River Basin was estimated from GHCND pan-evaporation 

observations (Figure 46). For details, see Appendix D for average monthly 

evaporation from each NID impoundment. These annual estimates are a 

function of GHCND data availability, location of the impoundment, and 

surface area at the normal pool elevation of the impoundment. As 

expected, the largest impoundments along the Mississippi River and its 

major tributaries have the greatest amounts of potential evaporation, as 

well as impoundments in the southern half of the river basin.

Although river modification in various parts of the basin began in the early 

1800s, rapid and widespread dam construction did not begin in earnest 

until passage of the Pick-Sloan Flood Control Act in 1944. The cumulative 

effect of NID impoundments on potential evaporation over time is shown 

in Figure 47, where the cumulative evaporation is based on the total 

impounded area at the mid-point of each decade. Clearly, there have been 

drastic increases in evaporation over the past century across the basin.

Figure 46. Average annual evaporation from NID impoundments. 
MRG&P Report No. 34 77

Assuming that potential evaporation from NID impoundments is roughly 

equivalent to actual evaporation, average effective rainfall can then be 

estimated by subtracting evaporation from total rainfall. Changes in the 

percentage of average annual evaporation versus average annual rainfall 

by HUC-4 is shown in Figure 48. 

Figure 47. Average-annual potential evaporation from impoundments, 

by decade. 
MRG&P Report No. 34 78

Figure 48. Percentage of average-annual potential evaporation from 

HUC-4s relative to decadal average-annual rainfall by decade. 

At the HUC-2 level, the total potential evaporation of water behind NID 

dams surpassed 3% of the decadal average rainfall volume in the 

Tennessee River Basin since the 1940s and in the Arkansas/Red/White 

Basin since the 1970s. At the basin level, the percentage of NID 

evaporation compared to total rainfall exceeded 2% starting in the 2000s. 

In several HUC-4s, the total potential evaporation of water behind NID 

dams, at some point, reaches a value greater than 5% of the of decadal 

average rainfall volume (Table 2).

Table 2. HUC-4s with greater than 5% of potential 

evaporation relative to annual rainfall. 

HUC-4 HUC-4 Name 

Earliest 

Decade 

0711 Upper Mississippi-Salt 1990s

0713 Lower Illinois 1940s

1003 Missouri-Marias 1960s

1014 Missouri-White 1970s

1101 Upper White 1960s

1107 Neosho-Verdigris 2010s

1109 Lower Canadian 1960s

1113 Red-Washita 1980s
MRG&P Report No. 34 79

Peak annual trends

Recalling that this analysis identifies human-induced changes, annual, 

maximum daily (Figure 49), 3-day, 5-day, and 7-day precipitationweighted water yields showed persistent regional trends of decreasing

yields in the western and far eastern parts of the Mississippi River Basin. 

In the west, it is assumed that this is due to dam operations and 

withdrawals for irrigation. In contrast, anthropogenic impacts resulted in 

increasing peaks within the Interior Plains. These increases throughout 

the mid-continent are generally thought to be the result of large-scale 

channelization programs which although resulted in incision, widening 

and increased sediment loads (Simon 1989a,b; Simon 1994; Simon and 

Rinaldi 2000), did in fact increase conveyance and peak flows by 

providing for a more efficient hydraulic system. In many sub-regions, 

agricultural practices are thought to strongly influence the observed 

precipitation-weighted yields. For example, along the western floodplain 

of the LMR, the region is dominated by rice production where continuous 

flooding of fields is a widespread practice (Massey et al. 2014). Indeed, this 

region is easily identified in the Moore et al. (2015) maps of irrigationrelated water use in the United States (Figure 50).

In terms of the percent change, the Upper Cimarron (1104) experienced 

the greatest decrease in maximum weighted yield across all durations 

analyzed (> 100%). In areas of the Upper Mississippi and Missouri, such 

as the Minnesota (0702), Upper Mississippi-Iowa-Skunk-Wapsipinicon

(0708), James (1016), Platte (1020), Kansas (1027), and Lower Missouri 

(1030), precipitation-weighted water yield increased by more than 100% 

across all durations. 
MRG&P Report No. 34 80

Figure 49. Percent change in maximum-daily precipitation-weighted water yield for all HUC-4s (top left) and for HUC-4s with statistically 

significant trends only (top right). Change for All HUC-4s (bottom), with significant trends shown in blue. 

 

 
MRG&P Report No. 34 81

Figure 50. Consumptive water use in the conterminous United States 

(from Moore et al. 2015). 
MRG&P Report No. 34 82

Seasonal trends

Seasonal trends in precipitation-weighted water yield reflect differences in 

how anthropogenic influences at different times of the year have effected 

long-term changes. Thus, seasonal differences in activities such as irrigation 

and flow regulation may be identified. Year-round, it appears that median, 

precipitation-weighted water yields from the Lower Missouri have increased 

Figure 51–Figure 54), probably reflecting the change in winter flow regimes 

along the release-controlled Missouri River and major tributaries. 

Winter water yields have increased across much of the basin, with some 

HUC-4s in the upper basin (1004, 1009, 1025, and 1104) showing 

persistent decreases throughout the season. During the spring, weighted 

yield decreased in the Wisconsin (0707), Allegheny (0501), Green (0511), 

Cumberland (0513), and across most of the Tennessee River Basin. 

Increases in water yields across much of the Interior Plains were also 

observed during the summer and fall. Spatial patterns in the spring and 

summer show reductions in water yield across vast areas of the basin 

probably owing to irrigation that reduces the amount of water available 

for streamflow.

Seasonal patterns of precipitation-weighted water yields are, again, likely 

highly influenced by agricultural practices. As noted by Kochendorfer and 

Hubbart (2010), the direction and magnitude of seasonal trends in 

streamflow in the Upper Mississippi cannot always be explained by 

precipitation alone and attributed the patterns to rural land use (i.e., 

agricultural) changes. This is also what the precipitation-weighted water 

yield results contained herein are indicating. If the changes in water yield 

were directly compared to precipitation-weighted water yield across the 

basin’s sub-regions, it would be found that the differences are not great, 

indicating that anthropogenic effects are critical, if not the most 

important, in understanding the changes in hydrology observed over the 

past century.

Similarly, decreases in fall and winter water yields in HUCs 0807 (Lower 

Mississippi-Lake Maurepas) and 0808 (Coastal Louisiana) could be due to 

widespread rice production in the area. Approximately 65% of the rice 

grown in the United States is produced in the LMR Valley where fields are 

continuously flooded with irrigation water derived from the Mississippi 

River Valley alluvial aquifer (Massey et al. 2014). 
MRG&P Report No. 34 83

Figure 51. Percent change in winter precipitation-weighted water yield for all HUC-4s (top left) and for HUC-4s with statistically significant 

trends only (top right). Change for all HUC-4s (bottom), with significant trends shown in blue. 

 

 
MRG&P Report No. 34 84

Figure 52. Percent change in spring precipitation-weighted water yield for all HUC-4s (top left) and for HUC-4s with statistically significant 

trends only (top right). Change for all HUC-4s (bottom), with significant trends shown in blue. 

 

 
MRG&P Report No. 34 85

Figure 53. Percent change in summer precipitation-weighted water yield for all HUC-4s (top left) and for HUC-4s with statistically significant 

trends only (top right). Change for all HUC-4s (bottom), with significant trends shown in blue. 

 

 
MRG&P Report No. 34 86

Figure 54. Percent change in fall precipitation-weighted water yield for all HUC-4s (top left) and for HUC-4s with statistically significant trends 

only (top right). Change for all HUC-4s (bottom), with significant trends shown in blue. 

 

 
MRG&P Report No. 34 87

Peak seasonal trends

Results show that there is a distinct spatial shifting of significant 

influences from season to season. As the spatial patterns of seasonal 

trends in precipitation-weighted water yield are similar to the distribution 

for peak values, the authors only provide discussion of these results 

without the customary supporting maps.

Winter trends

Winter peak water yields have increased across the Great Plains in 

Wyoming, Nebraska, and the Dakotas as well as sporadically across the 

Interior Plains. Decreasing trends were observed in Powder-Tongue 

(1009), Republican (1025), along the Arkansas (1103, 1106), Upper 

Cimarron (1104), and in the Beouf-Tensas (0805). Aside from decreased

yields in the upper Ohio River Basin, regional patterns of peak winter 

yields are nearly identical to overall winter precipitation-weighted yields.

Spring trends

Increased springtime precipitation-weighted water yields are less 

ubiquitous than in wintertime in the Interior Plains and shift such that 

decreased yields dominate the far western half of the river basin and were 

also observed in the Wisconsin (0707), the upper Ohio (0501, 0503), and 

parts of the Lower Mississippi.

Spring flood flows in the Minnesota (HUC 0702) increased over the period 

of record, with rapid increases occurring in the last 20 years. Using a 

similar technique, Novotny and Stefan (2007) analyzed seven 

precipitation-weighted streamflow metrics in the Minnesota and observed 

the same phenomena. 

Summer trends

Trends in maximum precipitation-weighted summertime water yields 

show a distinct divide in trend direction, with decreased yields only in the 

western parts of the basin (Upper Missouri, Arkansas, and Red Rivers) 

and increased yields throughout the Interior Plains and extending into the 

Lower Mississippi. In a recent study on the effects of land use/land cover 

on streamflows in the Upper Mississippi, Schilling et al. (2010) related 

increasing flows to increased soybean production based on measurements 

from the USGS gage in Keokuk, Iowa.
MRG&P Report No. 34 88

Fall trends

Trends in fall precipitation-weighted maximum water yields increased in 

the lower and middle Ohio and in the Lower Mississippi across all 

durations. This could be related to how land use changes in these subregions have interacted with the heightened intensity of hurricanes over 

the period. Regionally, the increases in water yield surpassed increases in 

fall precipitation (Figure 21–Figure 22).

Regional patterns of decreasing seasonal totals and maximum totals of 

precipitation-weighted water yields closely resemble the Moore et al. 

(2015) maps of seasonal consumptive water use (Figure 55). For additional 

details/results of the sub-regional precipitation-weighted water yield 

analyses, see Appendix G. 

Figure 55. Seasonal estimates of consumptive water use (from Moore et al. 2015). 
MRG&P Report No. 34 89

Summary of precipitation-weighted water yield results: anthropogenic 

influences

Although the direction of the changes varies across the basin, these effects 

are widespread and sizeable in magnitude, indicating that anthropogenic 

influences have been a major determining factor on changes in streamflow 

regimes over the past century. While anthropogenic activities have resulted 

in increases in water yield in the central part of the basin, activities at the 

basin margins have caused decreases in flow. The direction and magnitude 

of these influences can clearly be sorted by region (Figure 39):

• Western-most part of the basin - Decreases: Widespread 

reductions in water yield due to anthropogenic activities 

characterize these HUC-4s. Decreases in the range of -25% 

to -100% are typical. This includes most of the upper Missouri (e.g., 

main stem Missouri down to Oahe, the Yellowstone, Platte, 

Republican and Smoky Hill Rivers), upper and middle Arkansas 

and upper Red Rivers (e.g., Canadian and Cimarron Rivers).

• Central part of the basin - Increases: Anthropogenic activities have 

resulted in significant increases in water yield throughout this region, 

with the magnitude of the increase generally decreasing from west to 

east. The largest effects (50%–100%) are seen in the middle and 

lower sections of the Missouri River, the lower Arkansas and parts of 

the upper Mississippi (e.g., Minnesota and Des Moines), 

transitioning to moderate increases (10%–50%) in the mid-continent 

and tailing off to 0%–10% in the middle Ohio River basin.

• Eastern-most part of the basin- Decreases: Human activities have 

resulted in mild decreases (generally 0% to 10%) in water yield in 

the upper basins of the Ohio and moderate decreases (-10% to -25% 

in the upper and middle Tennessee River basins.

• Southern-most part of the basin - Decreases: The lower-most subbasins of the lower Mississippi and Red River have had moderate 

reductions in water yield as a result of human activities. The 

greatest decrease has been in the Boeuf-Tensas (0805).

Seasonally, the spatial distribution of anthropogenic influences on water 

yield look much like those on an annual basis as described in the bulleted 

points above. There are striking differences during the winter in the 
MRG&P Report No. 34 90

middle and lower Missouri basin and the Red and Washita Rivers, where 

winter flow releases are significantly greater now (>100%) than under the 

natural flow regimes before the dams.

Evaporation behind impoundments has increased drastically over the past 

century with the construction of thousands of dams, which peaked in the 

1960s and 1970s. Through the 1930s, evaporation relative to average

annual rainfall was approximately 0.1%. Starting in the 1960s and 

certainly by the 1980s, broad swaths of the Arkansas and Red River basins 

were losing more than 5% of their rainfall from evaporation behind 

impoundments.

Streamflow trends from index stations

To this point, this report has dealt with the spatial distribution and 

magnitude of changes in hydrology for all stations throughout the 

Mississippi River basin and expressed results as a percent increase or 

decrease. This section first concentrates on the changes in discharge (in 

percent) from all index stations representing the HUC-4s before focusing 

on changes and delivery of water directly to the LMR from the major 

HUC-2 basins. These results are shown as both percentages and absolute 

values.

All index stations

Annual trends

Analysis of discharge for index stations (those representing downstream 

locations in the HUC-4s) provide direct evidence of how contributions 

from the major drainages in the Mississippi River Basin have changed over 

time. This analysis spans the entire period of data, conveniently described 

as starting approximately 1900. In this section, only statistically 

significant monotonic trends (p < 0.05) are considered and presented. The 

reader is referred to Appendix A for details on the individual USGS 

streamflow gages used in this analysis, including drainage area and the 

period of record for each station. 

The most important result from this analysis is that much of the interior 

part of the basin shows important increases in annual streamflow 

emanating from the HUC-4 basins. That said, some trends of decreasing 

streamflow for various sub-regions in the upper Missouri and Arkansas 
MRG&P Report No. 34 91

River Basins are identified (Figure 56). Each index station is represented 

as the footprint of its drainage basin with the largest basins on the bottom 

and successively smaller contributing basins overlain on top. 

Note that significant decreasing trends were observed along the Missouri 

River at Fort Benton, Montana (USGS 06090800), and at Garrison Dam, 

North Dakota (USGS 06338490); otherwise, the majority of the index 

stations show trends of increasing annual streamflow. Likewise, index 

stations along the upper reaches of the Arkansas River showed decreasing 

streamflow trends at several locations above Wichita, Kansas. This 

highlights the fact that increasing flows in the lower parts of the Missouri 

and Arkansas River Basins outpaced the decrease in flows in the upper 

reaches, providing a net positive trend in annual streamflows.

One possible explanation for these patterns of streamflow in the central 

region of the basin is that groundwater pumping for irrigation from the 

High Plains aquifer (which includes the Ogallala aquifer) running from 

Nebraska to the panhandle of Texas leads to reduced streamflows and 

increased evapotranspiration in this area. This in turn causes hydrologic 

changes to the east of this zone including (1) increased summer 

precipitation through the atmospheric transfer of water vapor and (2) 

increased summer streamflows in states such as Illinois, Indiana, Ohio, 

Kentucky, and Tennessee (Kustu et al., 2011). These results may indeed 

apply to other states in the interior of the basin as well. The spatial pattern 

of precipitation provided in this study seem to substantiate these findings. 

It is clear, however, that there has been an increase in precipitation in this 

part of the basin and that the increasing water yields associated with this 

greater hydrologic input as well as more efficient channels and tile 

drainage can also be responsible for these increases in flow. Results are 

also in agreement with findings of Sagarika et al. (2014) who examined 

streamflows from 1951–2010 and detected positive trends in annual 

streamflows throughout the interior of the Mississippi River Basin. 
MRG&P Report No. 34 92

Figure 56. Change in annual streamflow at index stations with significant trends over 

the past century. 

Peak annual trends

Maximum values are derived from mean daily streamflows and not 

instantaneous peaks. Because of the increasing role of dams with increasing 

drainage area, changes in peak streamflow from index stations over the past 

century may largely be the result of upstream impoundments and flow 

regulation that are often designed to limit downstream flooding. In the 

upper parts of the Missouri, Arkansas, Ohio, and Tennessee River Basins, 

maximum daily and 7-day streamflows emanating from the HUC-4 index 

stations were observed to decrease significantly, probably as a result of 

effective flood-control efforts by dam operations. Detected trends in the 

maximum daily streamflows for all index stations are shown in Figure 57. In 

contrast, flows in parts of the middle Missouri (South Platte and James 

Rivers) and in the Upper Mississippi showed increasing streamflow trends, 

the latter probably as a result of increased precipitation and the previously 

mentioned anthropogenic changes to channel pattern and tile drainage. 
MRG&P Report No. 34 93

Figure 57. Change in maximum-daily streamflow at index stations with 

significant trends. 

Seasonal trends

Results from the HUC-4 index stations show that for the most part, winter 

streamflows increased across most of the study area (Figure 58), with a 

few decreasing trends located in the western half. During the spring 

(Figure 59), summer (Figure 60), and fall (Figure 61), streamflow in the 

West is actually dominated by decreasing streamflows, possibly due to the 

practice of storing water behind impoundments for the summer irrigation 

season. Spring streamflows were also observed to decrease along the 

Tennessee River, and decreasing summertime flows were observed in the 

upper Ohio.
MRG&P Report No. 34 94

Figure 58. Change in winter streamflow at index stations with significant trends. 

Figure 59. Change in spring streamflow at index stations with significant trends. 
MRG&P Report No. 34 95

Figure 60. Change in summer streamflow at index stations with significant trends. 

Figure 61. Change in fall streamflow at index stations with significant trends. 

Additional details/results of the streamflow analyses from index stations, 

including results not shown here, can be found in Appendix H.
MRG&P Report No. 34 96

Major (HUC-2) index stations

Annual trends

A comparison of the relative flow contributions from the major HUC-2 

basins to the LMR were computed over a fixed interval, 1930–2014. 

Discharges for these 2 years were based on values derived from the linear 

regression of mean daily and total flow over the period. In 1930, the 

relative contributions to average- and total-annual flow from the Ohio, 

Upper Mississippi, and Missouri Rivers were 61%, 23%, and 16%, 

respectively. By 2014, contributions from these three major suppliers 

shifted slightly to 55% from the Ohio, 28% from the Upper Mississippi,

and 18% from the Missouri. In general, the amount of water being 

delivered to the LMR has increased over the past century. Total annual 

and annual average flows have increased at all index stations emanating 

from the major river basins (or HUC-2s) over the period of record (Figure 

62). The percent-change values shown in the small tables associated with 

this and similar figures to follow will be slightly different than those cited 

above because these are based on the specific periods of record and not the 

fixed period of 1930 and 2014. Other than flows from the Upper 

Mississippi, all records start before the dust bowl era of the 1930s. The 

actual average increases in mean daily flows from the three main basins to 

the upstream boundary of the LMR are as follows:

• Ohio River: 1,674 m3/s (23.8%)

• Upper Mississippi River: 1,767 m3/s (66.0%)

• Missouri River: 986 m3/s (54.8%).

This comes to an increase in average mean-daily flows, of approximately 

4,427 m3/s (156,000 ft3/s). Integrated over an average year and excluding 

inputs from other smaller tributaries, this brings the average annual 

increase in flows to the Lower Mississippi to approximately 1.62 million 

m3/s (57.2 million ft3/s).
MRG&P Report No. 34 97

Figure 62. Change in annual total and annual average streamflow at major index 

stations. 

The overall spatial patterns of where increasing and decreasing flows have 

occurred is consistent with those shown previously using all stations 

within each HUC-4, with the mid-continent showing general increases and 

the western basins showing general decreases over the period.

The actual discharge values derived from the start (1930) and end (2014) 

of the linear regressions (as from Figure 62 for example) are tabulated for 

these and all other metrics in this section. These data, along with the 

relative contributions to the LMR from each HUC-2 and for each metric 

are listed in Table 3.

Peak mean daily trends

Peak mean daily streamflows from the Upper Mississippi River, measured 

at Thebes, showed significant increases over the period of record, for all 

durations (Figure 63). Increases from the other HUC-2s were not deemed 

statistically significant at the 0.05 level except for the 3-day maximum 

from the Missouri River Basin, which also increased significantly. The 

actual increases in the average daily-maximum values emanating from the 

Upper Mississippi River since 1934 (77 years of record) are the following:

• 1-day: 2,990 m3/s, (105,000 ft3/s for one day)

• 3-day: 3,430 m3/s, (121,000 ft3/s per day)

• 5-day: 3,300 m3/s, (117,000 ft3/s per day)

• 7-day: 3,570 m3/s, (126,000 ft3/s per day).
MRG&P Report No. 34 98

Table 3. Changes and percent contributions in discharge between 1930 and 2014 

from the major (HUC-2) index stations as derived from the linear regressions 

of annual data. 

Flow Metric HUC-2 Basin

Flow in 1930 

(m3/s)

% Contribution 

in 1930

Flow in 2014 

(m3

/s)

% Contribution 

in 2014

Change in 

Flow (m3

/s)

Missouri River 7,376 17.5% 8,545 20.2% 1,170

Ohio River 25,633 60.7% 24,864 58.9% -769

Upper Mississippi River 5,620 13.3% 8,800 20.8% 3,180

Total 38,629 42,210

Missouri River 1,798 15.6% 2,784 17.5% 986

Ohio River 7,040 61.1% 8,714 54.7% 1,674

Upper Mississippi River 2,678 23.3% 4,446 27.9% 1,767

Total 11,516 15,943

Missouri River 656,496 15.6% 1,016,769 17.5% 360,274

Ohio River 2,571,681 61.1% 3,181,919 54.7% 610,238

Upper Mississippi River 978,278 23.3% 1,623,329 27.9% 645,052

Total 4,206,454 5,822,018

Missouri River 3,135 26.8% 4,642 23.1% 1,507

Ohio River 5,558 47.6% 11,399 56.6% 5,840

Upper Mississippi River 2,995 25.6% 4,088 20.3% 1,093

Total 11,689 20,129

Missouri River 111,917 23.6% 210,311 24.2% 98,394

Ohio River 198,889 42.0% 422,056 48.5% 223,167

Upper Mississippi River 162,775 34.4% 238,477 27.4% 75,702

Total 473,580 870,843

Missouri River 5,602 16.4% 7,456 19.0% 1,854

Ohio River 22,711 66.3% 22,918 58.3% 207

Upper Mississippi River 5,926 17.3% 8,957 22.8% 3,031

Total 34,239 39,331

Missouri River 225,152 12.9% 325,184 15.6% 100,032

Ohio River 1,132,068 64.7% 1,140,648 54.7% 8,581

Upper Mississippi River 392,174 22.4% 621,321 29.8% 229,147

Total 1,749,394 2,087,153

Missouri River 5,446 30.8% 6,163 24.7% 717

Ohio River 8,868 50.1% 11,330 45.5% 2,462

Upper Mississippi River 3,385 19.1% 7,427 29.8% 4,042

Total 17,699 24,921

Missouri River 209,517 26.0% 278,508 23.2% 68,991

Ohio River 349,477 43.4% 480,738 40.1% 131,260

Upper Mississippi River 245,419 30.5% 440,790 36.7% 195,371

Total 804,414 1,200,036

Missouri River 2,905 10.9% 4,281 13.0% 1,376

Ohio River 20,236 76.1% 22,647 68.6% 2,411

Upper Mississippi River 3,459 13.0% 6,078 18.4% 2,619

Total 26,599 33,005

Missouri River 88,188 8.2% 176,283 11.2% 88,095

Ohio River 817,875 76.1% 1,098,349 69.9% 280,474

Upper Mississippi River 169,118 15.7% 296,800 18.9% 127,682

Total 1,075,181 1,571,432

Summer.1DayMax.Flows

Spring.Flows

Spring.1DayMax.Flows

Fall.Flows

Fall.1DayMax.Flows

Annual.Flows

Annual.1DayMax.Flows

Annual.Avg.Flows

Winter.Flows

Winter.1DayMax.Flows

Summer.Flows
MRG&P Report No. 34 99

Figure 63. Change in maximum daily streamflow at major index stations. 
MRG&P Report No. 34 100

Seasonal trends

Increases in seasonal streamflows from the Ohio, Upper Mississippi, and 

Missouri were detected in all seasons, although flows in the Lower 

Mississippi were found to increase only during the winter, summer, and 

fall months (Figure 64).

Figure 64. Change in seasonal streamflow at major index stations. 
MRG&P Report No. 34 101

Peak winter trends

For the period of record, peak winter streamflows at the major index 

stations were only detected from the Upper Mississippi (Figure 65). 

Although increases calculated from linear regressions are reported across 

all of the durations for the other major basins, none are considered to be 

statistically significant trends at the 0.05 level of probability.

Figure 65. Change in maximum winter streamflows at major index stations. 
MRG&P Report No. 34 102

Peak-spring trends

Like wintertime flows, springtime maximum streamflow totals were 

detected only in the Upper Mississippi over the period of record (Figure 

66). All detected trends were positive in the range of 40%–48%.

Figure 66. Change in maximum spring streamflows at major index stations. 
MRG&P Report No. 34 103

Peak summer trends

Large increases in summer peak flows (>100%) were identified from the 

Upper Mississippi, and while flows entering the Lower Mississippi at 

Hickman, Kentucky, did not increase, peak flows at Tarbert Landing, 

Louisiana, did show a significant increase (Figure 67). A possible reason for 

this discrepancy is the apparent decrease in summer peak flows from the 

Ohio (although not statistically significant). At Thebes, Illinois, the 

Mississippi River (with inputs from the Missouri) showed significant 

increases in 3-day, 5-day, and 7-day total summer maximum flows. At the 

time of this writing, at Thebes, there was ~32,000 m3/s more streamflow 

over the course of a week than there was approximately 80 years ago. Again, 

all of the other basins show increases but are not statistically significant.

Figure 67. Change in maximum summer streamflows at major index stations. 
MRG&P Report No. 34 104

Peak fall trends

Over the last 100 years, maximum fall streamflows appear to have 

increased across most of the Mississippi River Basin (Figure 68) except for 

the extreme western parts of the basin. These results are in keeping with 

those previous showing that changes in fall precipitation and streamflows 

are significant and almost ubiquitous. Flows exiting the Ohio River and 

along the Mississippi River (at St. Louis, Missouri; 07010000) exhibited 

increased trends in maximum fall streamflows across all durations 

analyzed. Downstream at Memphis, Tennessee (07032000), the 

Mississippi River also showed significant increases in streamflow across 

all durations, except that the last complete year of record was in 1993. 

Figure 68. Change in maximum fall streamflows at major index stations. 
MRG&P Report No. 34 105

Summary of streamflow trends from index stations results

The most important result from the analysis of the HUC-4 index stations is 

that discharges from much of the interior part of the basin show important 

increases in annual streamflow over the past century (from 25% to >100%). 

Still, some trends of decreasing streamflow for various sub-regions in the 

upper Missouri and Arkansas River Basins are identified. In the upper parts 

of the Missouri, Arkansas, Ohio, and Tennessee River Basins, maximum

daily and 7-day streamflows emanating from the HUC-4 index stations were 

observed to decrease significantly, probably as a result of effective floodcontrol efforts by dam operations.

HUC-4 seasonal distributions are similar to the annual ones with the 

exception of during the winter, where increases in flow extend well up into 

the Missouri Basin, reflecting the release of water under ice-covered rivers. 

Also striking are the large (25% to >100%) widespread increases in 

discharge during the fall throughout the Mississippi River basin with the 

exception of the upper parts of the Missouri, Arkansas, and Red Rivers, 

which showed decreases during this season.

In 1930, the relative contributions to average and total annual flow from 

the Ohio, Upper Mississippi, and Missouri Rivers were 61%, 23%, and 

16%, respectively. By 2014, contributions from these three major suppliers 

shifted slightly to 55% from the Ohio, 28% from the Upper Mississippi,

and 18% from the Missouri. In general, the amount of water being 

delivered to the LMR has increased over the past century. Total annual 

and annual average flows have increased at all index stations emanating 

from the major river basins (or HUC-2s) over the period of record. The 

actual average increases in mean daily flows from the three main basins to 

the upstream boundary of the LMR are the following:

• Ohio River: 1,674 m3/s (23.8%)

• Upper Mississippi River: 1,767 m3/s (66.0%)

• Missouri River: 986 m3/s (54.8%).

This comes to an increase in average mean daily flows of approximately 

4,427 m3/s (156,340 ft3/s). Integrated over an average year and excluding 

inputs from other smaller tributaries, this brings the average annual 

increase in flows to the Lower Mississippi to approximately 1.62 million 

m3/s (57.1 million ft3/s).
MRG&P Report No. 34 106

Peak annual streamflows (expressed as a daily value) from the Upper 

Mississippi River, measured at Thebes, showed significant increases over 

the period of record, for all durations:

• 1-day: 2,990 m3/s, (105,000 ft3/s)

• 3-day: 3,430 m3/s, (121,000 ft3/s)

• 5-day: 3,300 m3/s, (117,000 ft3/s)

• 7-day: 3,570 m3/s, (126,000 ft3/s).

Increases in seasonal streamflows from the Ohio, Upper Mississippi, and 

Missouri were detected in all seasons, although flows in the Lower 

Mississippi were found to increase only during the winter, summer, and 

fall months. 

Peak streamflow from HUC-4s

Peak (instantaneous) streamflow data from the USGS were used to 

determine the spatial variability for a range of recurrence intervals, 

ranging from the 1.5-year flow to the 100-year flow. This is not an analysis 

of change over time but a view of the spatial distribution of peak flows 

across the basin. To be able to utilize all of the available data within a 

given sub-region (HUC-4) and to then be able to compare these results 

with those from other sub-regions, all discharge values were divided by the 

appropriate drainage area to obtain water yield. The reliability of these 

estimates of course decreases with increasing recurrence interval. For 

brevity, only results for the Q1.5 (Figure 69), Q10 (Figure 70), and Q100 

(Figure 71) are mapped, although values for other recurrence intervals are

provided for each HUC-4 in Appendix I.

Results provide a clear picture of distribution of peak runoff production 

across the basin. As one would expect, the western, drier part of the basin 

tends to show the lowest water yields across the range of recurrence 

intervals with maximum values occurring in the Mississippi Embayment 

and extending northeast into the lower Ohio. Note that areas within the 

Mississippi Valley along the lower Mississippi (HUC 0802 and HUC 0805) 

appear as islands of lower water yields in a region of otherwise relatively 

high yields. This is possibly the result of large-scale pumping of the local 

aquifers, resulting in depressed streamflow rates. Olsen et al. (1999) 

examined the relation between climate variability and flood frequency 

estimates in the Upper Mississippi and Lower Missouri. 
MRG&P Report No. 34 107

Figure 69. Median drainage area-weighted Q1.5 by HUC-4. 

Figure 70. Median drainage area-weighted Q10 by HUC-4. 
MRG&P Report No. 34 108

Figure 71. Median drainage area-weighted Q100 by HUC-4. 

Sediment yield 

The primary focus of this investigation has been changes in precipitation 

and flow, including interpretations of the role of anthropogenic impacts on 

the latter. Entrainment and transport of sediment from the landscape and 

through the fluvial system is controlled to a large extent by hydrology, 

channel hydraulics, and sediment availability. This section provides the 

results of a basin-wide evaluation of changes in suspended-sediment 

transport over the past century as well as a comparison of the spatial 

distribution of current suspended-sediment transport rates. The spatial 

distribution of values is a function not only of regional difference in hydroclimatic regimes but also to differences in land and water use. Temporal 

changes within a given sub-region reflect changes in the magnitude and 

timing of runoff, alterations in land and water use, as well as direct 

alterations to stream channels and other anthropogenic effects such as 

dams and flow regulation.

To make comparisons between different-sized rivers, suspended-sediment 

loads were normalized by dividing by the drainage area of the station to 

obtain a suspended-sediment yield. This has been expressed in two ways:

• at the Q1.5, often associated with the effective discharge as t/d/km2

• and on an average annual basis as t/y/km2.
MRG&P Report No. 34 109

Values and trends at the effective (Q1.5) discharge

The long-term, suspended-sediment yield at the Q1.5 was calculated for 

each site using the single sediment-transport rating containing one or 

more linear segments (in log-log space). Thus, resulting values do not 

directly account for changes in hydrology or potential shifts in the 

sediment-transport rating relation, which will be shown later in this 

report to exhibit important declines in sediment yields. Gages without a 

corresponding Q1.5 value from flood-frequency analysis were assigned 

discharge values according to their relation between drainage area and 

Q1.5 for its associated HUC-4.

The spatial distribution of suspended-sediment yields at the effective 

discharge is shown in Figure 72. Maximum values occur in the Yazoo 

Basin (HUC 0803) with suspended-sediment yields of 154 t/d/km2 at the 

Q1.5. This supports earlier work by Simon et al., (2004) who identified the 

ecoregion encompassing this basin as having the highest suspendedsediment yields (at the Q1.5) in the continental United States. These yields 

are almost 2.5 times higher than the next largest yielding sub-region, the 

Lower Missouri (HUC 1030) at 64.1 t/d/km2. Other high-yielding subregions are, in decreasing order, the following: Red River Headwaters 

(HUC 1112; 59.1 T/d/km2); two sub-regions from the Upper Mississippi 

River (HUCs 0706 and 0704; 46.9 and 31.0 t/d/km2, respectively); the 

Kansas River (HUC 1027; 28.3 t/d/km2); and the Red-Washita River 

(HUC 1113; 20.7 t/d/km2). A complete list of the median yields by HUC-4 

at the Q1.5 is provided in Table J1 in Appendix J.
MRG&P Report No. 34 110

Figure 72. Median suspended-sediment yield at the Q1.5 by sub-region (HUC-4). 

Annual variations in suspended-sediment yields are of course related to 

the inter-annual variations in flow, often making it difficult to detect 

change over time. To get around this problem, analysis of sediment load or 

yield at a constant recurrence interval or flow frequency (such as the Q1.5) 

provides a convenient metric by which to accomplish this. Using the Q1.5 

is of further importance because of its implications for channel-forming 

processes and therefore representing the effective discharge.

Index stations, selected on the basis of their downstream location within 

each sub-region and the availability of as long a period of record as 

possible, were used to investigate temporal changes in suspendedsediment yield across the basin. Sediment-transport relations were 

developed for each decade of sediment sampling and solved for the yield 

at the Q1.5. In cases where it was appropriate (as with HUC 1111), data 

from proximal gaging stations on the same river were combined to 

increase the length of record if they were not separated by an 

impoundment. Data prior to the 1970s for the Tennessee River Basin 

could not be obtained from either the USGS or Tennessee Valley 

Authority but potentially could be accessed in the future from National 

Archives. The spatial distribution of results from the first and last 

decades of record is shown in Figure 73 and Figure 74 while a summary 

of the results is provided in Appendix J. The greatest suspendedsediment loads emanate from the Missouri River Basin, shown as the 

dark blue regions in Figure 73.
MRG&P Report No. 34 111

Figure 73. Suspended-sediment load at the Q1.5 for the earliest decade of data at 

sediment index stations (see Table J-2 for dates). 

Figure 74. Sediment load at the Q1.5 for the latest decade of data at sediment index 

stations (see Table J-2 for dates). 
MRG&P Report No. 34 112

Results of the comparison between the first and last decades of sediment 

record disclose large declines in suspended-sediment transport and 

delivery to the main-stem channels across most of the Mississippi River 

Basin. Much of this can be attributed to dams, trapping most of the 

sediment (including the silts and clays) delivered to the impoundments 

from upstream. Expressed as a percent decrease over the sampling period, 

the decreases in suspended-sediment yield are shown in Figure 75, and as 

an absolute value (in tonnes per day at the Q1.5) in Figure 76. The largest 

reductions in both percentage and amount are along the Missouri River. 

Meade and Moody (2010) attributed the large decline in sediment loads in 

the Mississippi River Basin from 1940 to 2007, primarily to the series of 

major dams along the Missouri River.

Figure 75. Change in suspended-sediment load at the Q1.5 at sediment index 

stations, expressed as a percent. Blank areas represent a lack of index stations.
MRG&P Report No. 34 113

Figure 76. Change in suspended-sediment load at the Q1.5 at sediment index 

stations, Expressed in tonnes per day. Blank areas represent a lack of index stations. 

Results from this study show that suspended-sediment loads at the Q1.5 

have declined from the outlets of all of the major tributaries draining to 

the LMR. Approximately 5 million fewer tons per day are reaching the 

LMR (excluding the Atchafalaya River) from its major tributaries at the 

Q1.5:

• Ohio River: -48.5% (286,000 t/d)

• Tennessee River: -46.4% (8,380 t/d)

• Upper Mississippi River: -47.3% (446,000 t/d)

• Lower Mississippi (Atchafalaya River): -30.0% (49,600 t/d)

• Missouri River: -86.1% (3,440,000 t/d)

• Arkansas River*: -95.7% (768,000 t/d)

• Red River: -90.5% (775,000 t/d).

*Note that this is not the most downstream site but that data start in the 

1940s. These results also assume that the Q1.5 has not changed over the 

period and in fact would probably be even more drastic (with the 

exception of the Upper Mississippi River) if the current Q1.5 were used for 

the latest period.
MRG&P Report No. 34 114

The starting period for each of the major index stations that were used in 

the comparison is listed in the second table in Appendix J.

Notwithstanding the marked decrease in suspended-sediment loads being 

delivered to the LMR from its major tributaries during the Q1.5, there are 

sub-regions that are providing greater loads currently than at the 

beginning of the sampling periods. These are located in the Upper 

Mississippi where approximately 50% of the index sites (sub-regions) are 

showing increases in suspended-sediment yields (Figure 77). This is 

related to the increase flows throughout much of the region. 

Approximately 10% of the stations in the Ohio and even the Missouri River 

Basins are showing increased loads. These in turn could be related to the 

incision of smaller tributary streams in response to lowering of bed levels 

of the trunk streams downstream from the major impoundments 

(Williams and Wolman 1984).

Figure 77. Frequency distribution of changes in suspended-sediment load at the Q1.5 

from sub-regions at sediment index stations. 

Annual trends

Calculating suspended-sediment transport rates at the Q1.5 is a convenient 

way to compare values over time and space but is difficult to comprehend 

in real terms. This is because one cannot simply multiply the values in 

tonnes per day by 365 to obtain average-annual values because a flow of 

0

10

20

30

40

50

60

70

80

90

100

-100 -50 0 50 100 150 200

PERCENTILE

PERCENT CHANGE FROM FIRST SAMPLING DECADE

Ohio River Upper Mississippi Lower Mississippi

Missouri River Arkansas River Red River
MRG&P Report No. 34 115

that magnitude (perhaps bankfull) does not occur every day, but on 

average, once every 1.5 years. To express sediment-transport results in a 

way that is conceptually easier to understand, a similar analysis has been 

conducted using average annual values. In this case, however, the study is 

at the mercy of the inter-annual variations in discharge that will of course 

affect calculations and interpretations of changes in average annual values. 

To accomplish this, data from 970 USGS gages with a sufficient number of 

discrete sediment samples and mean daily streamflow data were used. 

Gages used in this analysis have published drainage areas, instantaneous 

flows associated with each sediment sample, and sampled flows to within 

at least 25% of the Q1.5 estimated for the site.

Median annual suspended-sediment yields from the sub-regions vary over 

three orders of magnitude, ranging from 0.6 t/y/km2 in HUC-1016 (James 

River) to 514 t/y/km2 in HUC-1021 (Loup River). The central 50% of the 

distribution of median values ranges from 20.1 to 95.1 t/y/km2. Means 

range over four orders of magnitude (Figure 78).

Figure 78. Frequency distribution of annual suspended-sediment yields for all subregions (HUC-4s) in the Mississippi River Basin. 

Average annual suspended-sediment yields for each sampling station are 

displayed in Figure 79 while the median value for each sub-region, in 

Figure 80. The spatial distribution of results is quite similar to those 

shown previously for the Q1.5 with the highest values occurring in some of 

the same sub-regions (i.e., HUC 0803; Yazoo River). Yields greater than 

0

10

20

30

40

50

60

70

80

90

100

0.1 1.0 10.0 100.0 1000.0 10000.0

PERCENTILE

AVERAGE, ANNUAL SUSPENDED-SEDIMENT YIELD, IN TONNES PER 

DAY PER KILOMETER SQUARED

Medians Means
MRG&P Report No. 34 116

190 t/y/km2 are found in several sub-regions of the Missouri Basin’s Great 

Plains including HUC 1021, Loup River; HUC 1028, Chariton-Grand; HUC 

1024, Nishnabotna; HUC 1025, Republican, as well as HUC 1113 (RedWashita) in the Arkansas Basin and HUC 0507, (Big Sandy-Guyandotte) 

in the Ohio Basin. Areas of the lower Ohio River and Upper Mississippi 

also have reasonably high average annual-sediment yields. A complete list 

of the results of median and average annual suspended-sediment yields is 

provided by HUC-4 in Appendix J. These values represent basin-wide 

contributions of suspended-sediment across the Mississippi River Basin. 

Figure 79. Median annual sediment yield by gage. 
MRG&P Report No. 34 117

Figure 80. Average annual suspended-sediment yield by HUC-4 from gage medians. 

Annual suspended-sediment loads over the periods of sampling and flow 

record utilize data from all of the stations with sufficient data within each 

sub-region (HUC-4). Results are, therefore, a measure of changes in 

sediment production from streams of varying size. On average, the length of 

record for the HUC-4s is approximately 96 years, reflecting lengthy flow 

records for at least some of the gages in each HUC-4. In contrast, sedimentyield results reported from the index stations at the Q1.5 are a measure of 

sediment delivery out of the sub-region, discharging from the trunk stream 

and likely to be largely influenced by dams and flow regulation. 

Changes in median annual suspended-sediment yields within each of the 

sub-regions are shown in Figure 81 and reflect a broad range of hydrologic 

and anthropogenic changes over the past century. Marked decreases are 

observed across parts of the Upper Missouri, throughout the Arkansas and 

in parts of the Upper Ohio and LMR Basins. These decreases are probably 

the result of land- and water-use practices that result in less water in the 

channels. In contrast, increases in median annual yields have occurred 

throughout much of the mid-continent, including the Upper Mississippi 

and the lower Missouri Basins. Increased suspended-sediment yields 

reflect the documented increases in water yields in these regions as well as 

destabilization through incision and widening in response to 
MRG&P Report No. 34 118

anthropogenic disturbances such as lowering of trunk streams and 

channelization.

Note that although this analysis takes into account long periods of flow 

record, it utilizes a static sediment-transport rating for each site. Granted 

that this rating relation represents average conditions over the period of 

flow record for each gage, but it does not account for the rating shifts that 

have been observed at most of the index stations. The work here found 

that there was simply not a long enough sampling period at most USGS 

sediment stations to develop decadal ratings for all stations. A summary of 

the results for each HUC-4, including the maximum period of flow record 

and changes in median-annual, suspended-sediment yield is shown in 

Appendix J.

Figure 81. Changes in median-annual suspended-sediment yields over the period of 

record by HUC-4. 
MRG&P Report No. 34 119

Trends in annual sediment delivery to the Lower Mississippi from major 

index stations

To provide an evaluation of how sediment delivery to the LMR has 

changed over time, sediment-load data from the outlet of the major 

contributing rivers were considered. To account not only for changes in 

hydrology, but also for changes in the relation between flow and sedimenttransport rates, shifts in the rating relations were included in the analysis. 

Decadal sediment transport curves were developed for the following major 

index stations (Table 4):

• Ohio River at Metropolis, Illinois; USGS 06611500

• Missouri River at Hermann, Missouri; USGS 06934500

• Upper Mississippi River represented by loads at the Mississippi River 

loads at Thebes, Illinois; USGS 0702200, minus loads at the Missouri 

River at Hermann

• Arkansas River near Sallisaw, Oklahoma; USGS 07246500. 

Table 4. Decadal average annual sediment delivery to the Lower Mississippi. 

Decade Average Annual Sediment Load, in millions of tonnes [Mt] 

Ohio Missouri Upper Mississippi Arkansas Total 

1940s 49.6 360 47.3* 106 616

1950s 58.7α 268 45.1* 57.0 452

1960s 48.4α 259 β 43* 24.9 408

1970s 45.3 99.7 9.4 13.2 168

1980s 30.4 40.7 32.6 15.3γ 119

1990s 29.8 83.7 57.2 4.0 175

2000s 31.4 31.2 21.0 3.1 86.6

2010s 20.8 47.8 27.0 2.3 97.9

α Uses 1940s transport curve; β uses 1950s transport curve; γ uses 1970s transport curve.

* Estimated from extrapolation of trend from 1970s–2010s, back to 1940s.

Sediment data for the Ohio River were supplemented by observations at 

Dam 53 near Grand Chain, Illinois (USGS 03612500). Data for the 

Arkansas River were supplemented with samples from the station at 

Ft. Smith, Arkansas (USGS 07249455). Where sediment data were 

insufficient to develop decadal ratings, ratings from other decades were 

used as noted in the table. Annual sediment loads were then computed 
MRG&P Report No. 34 120

from daily loads using the associated mean daily streamflow and decadal 

ratings at each site.

In all cases, suspended-sediment loads from the major contributing 

streams show drastic monotonic decreases over the period 1940 to present 

(Table 5; Figure 82). The percent reduction in average-annual, suspendedsediment loads are 61% for the Ohio River, 33% for the Upper Mississippi 

River, 84% from the Missouri River, and 96% for the Arkansas River. In 

terms of the actual average annual reduction, the Missouri River by far 

had the greatest. Approximately 251 million tonnes (Mt) less suspended 

sediment are being discharged per year to the lower Mississippi today 

from the Missouri River than in the 1940s. In total, this represents 

approximately a 300% reduction in average annual suspended-sediment 

delivery from its major tributaries to the LMR, from approximately 616 

Mt/y in 1940 to approximately 98 Mt/y currently (Figure 83).

Numerous other researchers have similarly reported on a large decline in 

suspended-sediment loads discharged by the Mississippi River to the Gulf 

of Mexico (Keown et al. 1986; Meade and Moody 2010; Heimann et al.

2011). These reductions in loads have consequences for river stability, 

protection of hydraulic structures, nutrient transport, and replenishment 

of coastal wetland areas.

Table 5. Trends in annual sediment delivery to the Lower Mississippi at major index 

stations using decadal transport curves. 

River p < 

0.05 

Suspended-Sediment 

Load [Mt/y] Change in Load 

Min Year Max Year [Mt/y] %Change 

Ohio * 57.7 22.4 -35.3 -100 to -50%

Missouri * 299 47.8α -251 -100 to -50%

Upper Mississippi 48.2β 32.1 -16.1 -50 to -25%

Arkansas * 55.6 2.3α -53.3 -100 to -50%

α Regression crosses x-axis; decadal average substituted from Table 17.

β Regression extended back to 1940s.
MRG&P Report No. 34 121

Figure 82. Trends in annual sediment delivery to the Lower 

Mississippi at major index stations using decadal transport 

curves (see Table 5 for details). 
MRG&P Report No. 34 122

Figure 83. Decline in average annual delivery of suspended-sediment to the LMR. 

Summary of sediment-yield results

Suspended-sediment yields were calculated for all stations and all time 

periods at the Q1.5 to represent conditions at the effective discharge.

Maximum values occur in the Yazoo Basin (HUC 0803) with suspendedsediment yields of 154 t/d/km2 and are 2.5 times greater than the next 

largest yielding region. Other areas of high yields include parts of the 

Upper Red (HUCS 1112 and 1113), the Kansas and Lower Missouri (HUC 

1027 and 1030, respectively), and in two HUCS-4s in Upper Mississippi 

Rivers (704 and 706). In contrast, low-yielding regions (<0.25 t/d/km2) 

occur throughout the upper Missouri, the James River (HUC 1016) and the 

Mississippi Headwaters.

Index stations were used to establish transport relations by decade to 

evaluate the change in sediment transport over the period of sampling and 

to determine the spatial distribution of these changes. Results show that 

suspended-sediment loads at the Q1.5 have declined from the outlets of all 

of the major tributaries draining to the LMR. Approximately 5 million 

fewer tons per day are reaching the LMR (excluding the Atchafalaya River) 

from its major tributaries at the Q1.5:
MRG&P Report No. 34 123

• Ohio River: -48.5% (286,000 t/d)

• Tennessee River: -46.4% (8,380 t/d)

• Upper Mississippi River: -47.3% (446,000 t/d)

• Lower Mississippi (Atchafalaya River): -30.0% (49,600 t/d)

• Missouri River: -86.1% (3,440,000 t/d)

• Arkansas River*: -95.7% (768,000 t/d)

• Red River: -90.5% (775,000 t/d).

Still, there are some sub-regions that are providing greater loads currently 

than at the beginning of the sampling periods. These are located in the 

Upper Mississippi basin where approximately 50% of the index sites (subregions) are showing increases in suspended-sediment yields.

Using a data set of 970 gages, median annual suspended-sediment yields 

from the sub-regions were found to vary over three orders of magnitude, 

ranging from 0.6 t/y/km2 in HUC-1016 (James River) to 514 t/y/km2 in 

HUC-1021 (Loup River). The central 50% of the distribution of median 

values ranges from 20.1 to 95.1 t/y/km2. Changes in median annual 

suspended-sediment yields within each of the sub-regions reflect a broad 

range of hydrologic and anthropogenic changes over the past century. 

Marked decreases are observed across large parts of the Upper Missouri, 

throughout the Arkansas and Red River basins, and in parts of the Upper 

Ohio and LMR Basins. These decreases are probably the result of landand water-use practices that result in less water in the channels. In 

contrast, increases in median annual yields have occurred throughout 

much of the mid-continent, including the Upper Mississippi and the lower 

Missouri Basins. 

Sediment delivery to the LMR from the HUC-2 basins show drastic 

monotonic decreases over the period 1940 to present. The percent 

reduction in average annual suspended-sediment loads are 61% for the 

Ohio River, 33% for the Upper Mississippi River, 84% from the Missouri 

River, and 96% for the Arkansas River. Approximately 251 Mt less 

suspended sediment are discharged per year to the LMR today from the 

Missouri River than in the 1940s. In total, this represents approximately a 

500 Mt/y reduction in average annual suspended-sediment delivery from 

the major tributaries to the LMR, from approximately 616 Mt/y in 1940 to 

about 98 Mt/y currently (an 84% reduction).
MRG&P Report No. 34 124

5 Summary

Altered hydrological conditions in the LMR are a result of changes in 

precipitation, rainfall-runoff relations, and anthropogenic factors that play 

a role in the magnitude and frequency of hydrologic events. Numerous 

studies have shown the significance of climate change and extreme 

weather events on peak flows, low flows, and flooding, etc. Contributing to 

shifting hydrologic patterns such as precipitation are human-induced 

changes to the natural environment such as agriculture, urbanization, 

channelization, dam construction, etc., that often vary in a spatially 

systematic way according to regional demands for water. Changing flow 

regimes also affect suspended-sediment transport rates and channel 

stability, challenging on-going efforts in flood protection, stream 

restoration, and water-quality management.

Results of this study show that in general, although most of the Mississippi 

River Basin is receiving more rainfall than it did 100 years ago, there are 

vast areas where water yields have decreased significantly, particularly in 

the western part of the basin and particularly in spring. Precipitation has 

also shifted temporally such that winter precipitation has significantly 

decreased in many areas while spring and autumn precipitation has 

generally increased. Parts of the western basin are experiencing 25% to 

more than 50% less discharge per unit area than they did 100 years ago. In 

contrast, the mid-continent is generating considerably more water than it 

did 100 years ago. In part, this can be attributed to increases in 

precipitation and a greater influence of hurricane-related rainfall, but the 

anthropogenic effects cannot not be minimized. The result is that the LMR

is receiving more flow from its major HUC-2 tributaries (Ohio, Missouri,

and Upper Mississippi Rivers) than at the turn of the twentieth century. 

Integrating over an average year and excluding inputs from other smaller 

tributaries bring the average annual increase in flows to the LMR to 

approximately 1.62 million m3/s (57.2 million ft3/s). Average mean daily 

flow contributions from the Ohio, Upper Mississippi, and Missouri Rivers 

have changed from 61%, 23%, and 16% in 1930 to 55%, 28%, and 18% in 

2014, respectively.

Although the direction of the changes (positive or negative) varies across 

the basin, these effects are widespread and sizeable in magnitude, 

indicating that anthropogenic influences have been a major determining 

factor on changes in streamflow regimes over the past century. The 
MRG&P Report No. 34 125

direction and magnitude of these influences can clearly be sorted by 

region. While anthropogenic activities have resulted in increases in water 

yield in the central part of the basin (increases of 50%–100% decreasing 

eastward to 0%–10%), activities at the basin margins have caused 

decreases in flow. In the west, decreases of 25%–100% are typical.

Results of this study are in direct contrast with results of McCabe and 

Wolock (2014) over the same time period. Those authors concluded that 

precipitation variability accounts for nearly all the variability in observed 

runoff in the conterminous U.S. based on rainfall-runoff simulations.

Similar to the findings of McCabe and Wolock (2014), who determined 

that streamflow was only weakly correlated to known climate indices, the 

results of this study show unpredictability of water yields based solely on 

climate—in this case, precipitation.

Sediment yields were calculated for all stations with available data at the

channel-forming discharge (Q1.5) and on an annual basis. Results for both 

the downstream-most stations in each sub-region and for average 

conditions within each sub-region elucidate current rates of suspendedsediment transport as well as changes over the period of record. Suspendedsediment loads at the outlets of most sub-regions have drastically declined, 

from the major tributaries at the Q1.5, by 30% in the Arkansas, 46%–48% in 

the Tennessee, Upper Mississippi, and Ohio Basins, and 86% in the 

Missouri. Similar results were obtained for annual values. Still, increases in 

sediment yields are found in some sub-regions impacted by increased 

precipitation and water yields such as the upper Mississippi, and regions 

bordering the lower and middle Mississippi and Missouri Valleys where 

channels are responding to the lowering of the trunk streams downstream 

from dams or because of channelization activities. 

The average-annual delivery of suspended sediment to the LMR has

declined by approximately 84%, from approximately 616 Mt/y in 1940 to 

approximately 98 Mt/y, currently. The largest actual decline is from the 

Missouri River (approximately 250 Mt/y) largely due to the trapping of 

sediment behind impoundments. Decreases in sediment delivery to these 

reservoirs are also noted. Other researchers have similarly reported on a 

large decline in suspended-sediment loads discharged by the Mississippi 

River to the Gulf of Mexico. These reductions in loads have consequences 

for river stability, protection of hydraulic structures, nutrient transport, 

and replenishment of coastal wetland areas.
MRG&P Report No. 34 126

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MRG&P Report No. 34 131

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MRG&P Report No. 34 132

Appendix A: GHCND Gages

Table A-1. Timeframe for precipitation analysis by HUC-4. 

HUC4min 

Year

max 

Year n

HUC4min 

Year

max 

Year n

0501 1893 2014 117 1003 1899 2014 114

0502 1896 2014 116 1004 1906 2014 106

0503 1896 2014 117 1005 1912 2014 102

0504 1900 2014 115 1006 1911 2014 90

0505 1902 2014 112 1007 1908 2014 107

0506 1899 2014 116 1008 1913 2014 100

0507 1911 2014 96 1009 1912 2014 82

0508 1900 2014 115 1010 1909 2014 105

0509 1899 2014 115 1011 1911 2014 101

0510 1898 2014 116 1012 1911 2014 104

0511 1897 2014 106 1013 1901 2014 108

0512 1895 2014 120 1014 1904 2014 107

0513 1896 2014 119 1015 1910 2014 99

0514 1895 2014 119 1016 1896 2014 116

0601 1898 2014 117 1017 1899 2014 113

0602 1896 2014 106 1018 1900 2014 107

0603 1898 2014 114 1019 1898 2014 117

0604 1901 2014 110 1020 1902 2014 110

0701 1893 2014 119 1021 1897 2014 114

0702 1896 2014 118 1022 1899 2014 114

0703 1907 2014 79 1023 1897 2014 115

0704 1896 2014 98 1024 1896 2014 118

0705 1905 2014 79 1025 1893 2014 117

0706 1904 2014 96 1026 1900 2014 108

0707 1905 2014 100 1027 1894 2014 120

0708 1895 2014 120 1028 1894 2014 121

0709 1896 2014 115 1029 1897 2014 116

0710 1899 2014 116 1030 1895 2014 118
MRG&P Report No. 34 133

HUC4min 

Year

max 

Year n

HUC4min 

Year

max 

Year n

0711 1896 2014 112 1101 1897 2014 116

0712 1900 2014 111 1102 1897 2014 110

0713 1896 2014 117 1103 1901 2014 114

0714 1896 2014 118 1104 1903 2014 107

0801 1906 2014 106 1105 1900 2014 114

0802 1903 2014 108 1106 1910 2014 100

0803 1901 2014 114 1107 1895 2014 116

0804 1901 2014 108 1108 1905 2014 106

0805 1911 2014 102 1109 1907 2014 108

0806 1897 2014 112 1110 1909 2014 105

0807 1898 2014 107 1111 1892 2014 119

0808 1894 2014 115 1112 1908 2014 94

0809 1900 2014 111 1113 1901 2014 111

1002 1907 2014 102 1114 1903 2014 109
MRG&P Report No. 34 134

Appendix B: USGS Gage Information

Table B-1. Timeframe for water-yield analysis by HUC-4. 

HUC4Min 

Year

Max 

Year n

HUC4Min 

Year

Max 

Year n

HUC4Min 

Year

Max 

Year n

0501 1909 2014 106 0711 1923 2014 92 1017 1946 2013 68

0502 1908 2014 107 0712 1916 2015 100 1018 1905 2015 105

0503 1913 2014 102 0713 1909 2014 103 1019 1896 2015 120

0504 1922 2014 93 0714 1909 2014 103 1020 1938 2015 77

0505 1896 2014 113 0801 1930 2015 85 1021 1937 2013 77

0506 1922 2014 93 0802 1927 2015 88 1022 1946 2013 68

0507 1916 2014 87 0803 1909 2015 89 1023 1929 2015 80

0508 1915 2014 100 0804 1929 2015 86 1024 1923 2015 92

0509 1916 2014 87 0805 1939 2012 72 1025 1929 2015 87

0510 1916 2014 91 0806 1939 2015 76 1026 1919 2015 97

0511 1928 2014 81 0807 1941 2015 74 1027 1918 2015 98

0512 1910 2014 102 0808 1923 2015 78 1028 1922 2015 94

0513 1915 2015 101 0809 1909 2014 106 1029 1919 2014 96

0514 1929 2014 86 1002 1895 2014 109 1030 1926 2014 89

0601 1900 2015 116 1003 1903 2015 113 1101 1922 2015 93

0602 1899 2014 116 1004 1908 2013 98 1102 1897 2015 108

0603 1905 2014 98 1005 1904 2013 88 1103 1903 2015 95

0604 1921 2014 94 1006 1910 2015 81 1104 1943 2015 72

0701 1907 2014 108 1007 1908 2014 103 1105 1935 2015 79

0702 1912 2014 84 1008 1907 2015 104 1106 1937 2015 78

0703 1914 2014 101 1009 1920 2013 85 1107 1922 2015 93

0704 1912 2014 93 1010 1939 2013 65 1108 1908 2015 93

0705 1914 2014 101 1011 1905 2012 81 1109 1939 2015 76

0706 1920 2014 89 1012 1930 2014 78 1110 1938 2015 77

0707 1913 2013 101 1013 1909 2014 89 1111 1928 2015 87

0708 1903 2014 112 1014 1932 2013 82 1112 1905 2015 80

0709 1915 2014 100 1015 1939 2013 69 1113 1936 2015 79

0710 1916 2014 99 1016 1944 2013 70 1114 1925 2015 90
MRG&P Report No. 34 135

Table B-2. Timeframe for precipitation-weighted water yield analysis by HUC-4. 

HUC4Min 

Year

Max 

Year n

HUC4Min 

Year

Max 

Year n

HUC4Min 

Year

Max 

Year n

0501 1910 2014 105 0711 1923 2014 92 1017 1946 2013 68

0502 1908 2014 106 0712 1916 2014 99 1018 1905 2013 103

0503 1913 2014 102 0713 1909 2014 103 1019 1898 2014 117

0504 1922 2014 93 0714 1909 2014 103 1020 1938 2013 76

0505 1908 2014 107 0801 1930 2013 84 1021 1937 2013 76

0506 1922 2014 93 0802 1927 2013 87 1022 1946 2013 68

0507 1929 2014 85 0803 1909 2013 88 1023 1929 2013 79

0508 1915 2014 100 0804 1929 2013 85 1024 1923 2014 91

0509 1916 2014 87 0805 1939 2012 72 1025 1929 2014 86

0510 1916 2014 91 0806 1939 2009 69 1026 1919 2014 96

0511 1928 2014 81 0807 1941 2013 73 1027 1918 2014 97

0512 1910 2014 102 0808 1923 2013 77 1028 1922 2014 93

0513 1915 2014 100 0809 1910 2014 105 1029 1919 2014 96

0514 1929 2014 86 1002 1911 2014 94 1030 1926 2014 89

0601 1900 2014 115 1003 1903 2014 112 1101 1922 2013 92

0602 1902 2014 104 1004 1910 2013 96 1102 1897 2013 106

0603 1905 2014 98 1005 1915 2013 82 1103 1903 2013 94

0604 1921 2014 93 1006 1911 2012 75 1104 1943 2013 71

0701 1907 2014 107 1007 1908 2014 103 1105 1935 2013 77

0702 1912 2014 84 1008 1913 2013 98 1106 1937 2013 76

0703 1920 2014 77 1009 1932 2013 75 1107 1922 2013 92

0704 1912 2014 87 1010 1939 2013 65 1108 1908 2013 88

0705 1914 2014 77 1011 1930 2012 79 1109 1939 2013 75

0706 1920 2014 84 1012 1930 2014 78 1110 1938 2013 75

0707 1913 2013 94 1013 1910 2014 88 1111 1928 2013 86

0708 1903 2014 112 1014 1932 2013 82 1112 1938 2013 74

0709 1915 2014 99 1015 1939 2013 69 1113 1936 2013 78

0710 1916 2014 99 1016 1944 2013 70 1114 1925 2013 89

 
MRG&P Report No. 34 136

Table B-3. Index stations selected for calculating suspendedsediment yields at the Q1.5 for sub-regions. 

HUC-4 River Station 

First 

Decade 

Last 

Decade 

0502 Monongahela 03085000 1970 1990

0504 Muskingum 03150000 1970 1990

0506 Scioto 03234500 1960 1990

0507 Big Sandy 03215000 1970 1990

0509 Little Miami 03245500 1970 2000

0509 Ohio 03216600 1970 2010

0510 Kentucky 03290500 1970 1990

0512 Wabash 03378500 1970 2010

0512 White 03374100 1970 2010

0513 Cumberland 03425000 1970 1990

0514 Ohio 03612500 1940 2010

0604 Tennessee 03609750 1970 2010

0701 Mississippi 05331580 1970 2010

0702 Minnesota 05330000 1970 2000

0703 St Croix 05340500 1970 2000

0704 Black 05382000 1960 2000

0705 Chippewa 05369500 1960 1990

0706 Turkey 05412500 1950 2010

0707 Wisconsin 05407000 1970 2000

0708 Iowa 05465500 1970 2010

0709 Rock 05446500 1970 1990

0710 Des Moines 05490500 1970 2010

0711 Salt 05508000 1970 1990

0712 Illinois 05543500 1970 2000

0713 Illinois 05586100 1980 2010

0714 Kaskaskia 05594100 1970 1990

0714 Mississippi 07022000 1970 2010

0801 Hatchie 07030050 1970 2000

0802 White 07077800 1980 2010
MRG&P Report No. 34 137

HUC-4 River Station 

First 

Decade 

Last 

Decade 

0803 Yazoo 07288955 1970 2010

0805 Tensas 07369500 1970 1990

0806 Big Black 07290000 1970 1990

0808

Lower 

Atchafalaya 07381600 1970 2010

1003 Missouri 06054500 1970 2000

1004 Missouri 06115200 1970 1990

1005 Milk 06174500 1970 1990

1006 Poplar 06181000 1970 2000

1007 Yellowstone 06214500 1970 2000

1008 Bighorn 06294700 1960 1990

1009 Powder 06326500 1970 2010

1010 Yellowstone 06329500 1970 2010

1011 Little Missouri 06337000 1970 1990

1012 Belle Fourche 06437000 1950 1980

1013 Missouri 06342500 1940 2010

1014 White 06452000 1970 2010

1015 Niobrara 06465500 1970 1990

1016 James 06478500 1970 1990

1017 Big Sioux 06485500 1940 2010

1020 Platte 06805500 1950 2010

1022 Elkhorn 06800500 1940 2010

1023 Little Sioux 06607500 1940 2010

1024 Nishnabotna 06810000 1940 2010

1025 Republican 06856600 1940 2010

1026 Smoky Hill 06877600 1950 1990

1027 Kansas 06892350 1970 2010

1029 Osage 06926510 1970 1990

1030 Missouri 06934500 1940 2010

1101 White 07074500 1970 1990

1103 Arkansas 07146500 1940 2000
MRG&P Report No. 34 138

HUC-4 River Station 

First 

Decade 

Last 

Decade 

1104 Cimarron 07157580 1930 1980

1105 Cimarron 07161000 1940 1990

1106

Salt Fork 

Arkansas 07150500 1930 1980

1107 Neosho 07193500 1930 1990

1108 Canadian 07221500 1970 2010

1109 Canadian 07245000 1940 1980

1110 North Canadian 07242000 1940 1990

1111 Arkansas 07246500 1940 2010

1111 Arkansas 07250550 1970 2010

1113 Red 07308500 1970 1990

1113 Washita 07331000 1930 1990

1114 Red 07337000 1930 2010
MRG&P Report No. 34 139

Appendix C: National Inventory of Dams

Table C-1. Number and size of NID 

impoundments used in this study. 

HUC4 Number of 

Dams 

Total 

Surface 

Area 

[km2] 

501 115 201.2

502 94 95.7

503 210 386.2

504 72 142.2

505 65 77.1

506 66 68.7

507 22 32.3

508 47 63.1

509 80 310.9

510 93 112.5

511 113 175.1

512 221 303.1

513 88 906.1

514 141 440.0

601 85 2218.0

602 25 441.7

603 21 860.7

604 59 686.6

701 122 1336

702 100 249.4

703 79 171.2

704 104 443.8

705 137 432.9

706 67 471.5

707 143 285.1

708 188 551.2

709 68 256.7

710 312 193.1

711 338 504.6

712 37 114.3

713 23 1154

714 47 381.4
MRG&P Report No. 34 140

HUC4 Number of 

Dams 

Total 

Surface 

Area 

[km

2

] 

801 261 46.6

802 93 193.0

803 392 170.4

804 75 873.9

8055 30.3

806 49 20.3

8075 3.4

808 23 67.3

8092 0.08

1002 19 59.1

1003 32 406.9

1004 43 423.8

1005 93 228.2

1006 11 45.8

10079 9.6

1008 100 265.8

1009 23 16.7

1010 22 5.1

1011 51 17.1

1012 65 117.1

1013 158 824.1

1014 58 1828.0

1015 31 26.4

1016 80 79.4

1017 134 731.0

1018 100 611.2

1019 324 223.3

1020 235 88.1

1021 28 63.8

1022 23 5.4

1023 832 40.0

1024 862 102.5

1025 90 213.0

1026 121 400.0

1027 719 190.6

1028 908 147.1
MRG&P Report No. 34 141

HUC4 Number of 

Dams 

Total 

Surface 

Area 

[km

2

] 

1029 167 457.9

1030 276 33.8

1101 99 2394.0

1102 119 152.9

1103 294 185.7

11044 3.2

1105 83 47.7

1106 191 269.5

1107 480 807.0

1108 14 54.9

1109 130 772.6

1110 278 155.0

1111 263 847.3

1112 123 241.1

1113 1300 662.0

1114 345 1750
MRG&P Report No. 34 142

Appendix D: Average Monthly Evaporation at 

NID Impoundments

Figure D-1. Average January evaporation from NID impoundments. 

Figure D-2. Average February evaporation from NID impoundments. 
MRG&P Report No. 34 143

Figure D-3. Average March evaporation from NID impoundments. 

Figure D-4. Average April evaporation from NID impoundments. 
MRG&P Report No. 34 144

Figure D-5. Average May evaporation from NID impoundments. 

Figure D-6. Average June evaporation from NID impoundments. 
MRG&P Report No. 34 145

Figure D-7. Average July evaporation from NID impoundments. 

Figure D-8. Average August evaporation from NID impoundments. 
MRG&P Report No. 34 146

Figure D-9. Average September evaporation from NID impoundments. 

Figure D-10. Average October evaporation from NID impoundments. 
MRG&P Report No. 34 147

Figure D-11. Average November evaporation from NID impoundments. 

Figure D-12. Average December evaporation from NID impoundments. 
MRG&P Report No. 34 148

Appendix E: Precipitation Trends by HUC-4

Table E-1. Change in annual rainfall by HUC-4. 

HUC4 p < 0.05 

Year Rainfall [mm] Change in Rainfall 

Min Max Min Year Max Year [mm] %Change 

0501 * 1893 2014 1032.1 1142.5 110.4 10 to 25%

0502 1896 2014 1127.9 1166.2 38.3 0 to 5%

0503 1896 2014 995.2 1033.0 37.8 0 to 5%

0504 1900 2014 976.1 1013.5 37.4 0 to 5%

0505 1902 2014 1108.4 1082.7 -25.7 -5 to 0%

0506 * 1899 2014 928.4 1014.5 86.1 5 to 10%

0507 1911 2014 1097.3 1158.5 61.2 5 to 10%

0508 1900 2014 943.1 1030.9 87.8 5 to 10%

0509 1899 2014 1018.6 1104.7 86.1 5 to 10%

0510 1898 2014 1117.2 1223.9 106.7 5 to 10%

0511 1897 2014 1187.2 1299.4 112.2 5 to 10%

0512 * 1895 2014 989.4 1076.5 87.0 5 to 10%

0513 1896 2014 1248.1 1345.2 97.0 5 to 10%

0514 * 1895 2014 1075.6 1218.7 143.1 10 to 25%

0601 * 1898 2014 1164.8 1294.6 129.7 10 to 25%

0602 1896 2014 1316.3 1445.1 128.8 5 to 10%

0603 * 1898 2014 1300.8 1472.1 171.3 10 to 25%

0604 * 1901 2014 1238.8 1423.6 184.8 10 to 25%

0701 * 1893 2014 618.2 755.7 137.6 10 to 25%

0702 1896 2014 640.5 695.7 55.2 5 to 10%

0703 * 1907 2014 656.6 823.3 166.7 25 to 50%

0704 * 1896 2014 737.6 853.7 116.1 10 to 25%

0705 1905 2014 770.5 827.4 56.9 5 to 10%

0706 * 1904 2014 777.1 942.2 165.1 10 to 25%

0707 1905 2014 780.3 829.1 48.9 5 to 10%

0708 * 1895 2014 803.5 906.9 103.4 10 to 25%

0709 1896 2014 826.7 912.5 85.7 10 to 25%
MRG&P Report No. 34 149

HUC4 p < 0.05 

Year Rainfall [mm] Change in Rainfall 

Min Max Min Year Max Year [mm] %Change 

0710 1899 2014 782.5 838.3 55.8 5 to 10%

0711 1896 2014 885.8 984.1 98.3 10 to 25%

0712 * 1900 2014 800.3 979.7 179.5 10 to 25%

0713 * 1896 2014 859.2 959.5 100.3 10 to 25%

0714 1896 2014 995.7 1067.2 71.6 5 to 10%

0801 * 1906 2014 1225.1 1393.6 168.5 10 to 25%

0802 1903 2014 1214.6 1221.3 6.7 0 to 5%

0803 * 1901 2014 1264.8 1433.4 168.6 10 to 25%

0804 * 1901 2014 1267.5 1416.1 148.6 10 to 25%

0805 1911 2014 1302.3 1373.9 71.6 5 to 10%

0806 * 1897 2014 1320.0 1491.9 171.9 10 to 25%

0807 1898 2014 1442.3 1607.6 165.4 10 to 25%

0808 1894 2014 1407.9 1555.8 147.8 10 to 25%

0809 1900 2014 1542.4 1592.1 49.8 0 to 5%

1002 * 1907 2014 382.4 305.0 -77.4 -25 to -10%

1003 1899 2014 330.8 316.4 -14.5 -5 to 0%

1004 1906 2014 362.8 372.5 9.7 0 to 5%

1005 1912 2014 309.9 305.7 -4.2 -5 to 0%

1006 1911 2014 316.7 341.3 24.6 5 to 10%

1007 * 1908 2014 346.8 400.3 53.6 10 to 25%

1008 1913 2014 236.3 259.5 23.3 5 to 10%

1009 1912 2014 352.8 362.8 10.0 0 to 5%

1010 1909 2014 326.7 364.4 37.7 10 to 25%

1011 1911 2014 365.2 415.6 50.5 10 to 25%

1012 1911 2014 416.4 433.4 17.0 0 to 5%

1013 * 1901 2014 389.5 449.1 59.6 10 to 25%

1014 * 1904 2014 434.9 507.9 73.0 10 to 25%

1015 * 1910 2014 433.7 525.4 91.7 10 to 25%

1016 1896 2014 505.3 526.8 21.4 0 to 5%

1017 1899 2014 603.2 663.1 59.9 5 to 10%
MRG&P Report No. 34 150

HUC4 p < 0.05 

Year Rainfall [mm] Change in Rainfall 

Min Max Min Year Max Year [mm] %Change 

1018 1900 2014 364.7 336.5 -28.2 -10 to -5%

1019 1898 2014 382.9 418.7 35.8 5 to 10%

1020 1902 2014 621.4 693.1 71.8 10 to 25%

1021 1897 2014 586.0 613.3 27.2 0 to 5%

1022 1899 2014 659.2 696.2 37.0 5 to 10%

1023 * 1897 2014 677.2 768.0 90.9 10 to 25%

1024 1896 2014 820.6 847.6 27.0 0 to 5%

1025 1893 2014 524.8 562.0 37.2 5 to 10%

1026 1900 2014 570.3 600.8 30.6 5 to 10%

1027 1894 2014 727.9 791.7 63.9 5 to 10%

1028 1894 2014 866.4 973.6 107.3 10 to 25%

1029 1897 2014 969.6 1046.5 76.9 5 to 10%

1030 1895 2014 947.2 1025.0 77.8 5 to 10%

1101 1897 2014 1142.3 1162.3 20.0 0 to 5%

1102 1897 2014 404.4 336.0 -68.4 -25 to -10%

1103 * 1901 2014 599.9 728.2 128.3 10 to 25%

1104 1903 2014 477.1 429.0 -48.1 -25 to -10%

1105 1900 2014 723.5 808.1 84.6 10 to 25%

1106 1910 2014 752.8 872.6 119.8 10 to 25%

1107 1895 2014 957.8 1026.8 69.0 5 to 10%

1108 1905 2014 394.5 433.5 39.1 5 to 10%

1109 * 1907 2014 470.6 672.7 202.1 25 to 50%

1110 1909 2014 666.5 652.0 -14.6 -5 to 0%

1111 * 1892 2014 1035.1 1234.1 199.0 10 to 25%

1112 * 1908 2014 489.2 618.1 129.0 25 to 50%

1113 1901 2014 674.1 727.4 53.3 5 to 10%

1114 * 1903 2014 1073.6 1305.9 232.3 10 to 25%
MRG&P Report No. 34 151

Table E-2. Change in maximum annual daily rainfall by HUC-4. 

HUC4 p < 0.05 

Year Rainfall [mm] Change in Rainfall 

Min Max Min Year Max Year [mm] %Change 

0501 1893 2014 49.8 53.9 4.1 5 to 10%

0502 1896 2014 53.7 51.7 -2.0 -5 to 0%

0503 1896 2014 50.7 52.0 1.3 0 to 5%

0504 1900 2014 52.2 53.8 1.6 0 to 5%

0505 1902 2014 54.3 56.6 2.3 0 to 5%

0506 1899 2014 52.3 56.6 4.3 5 to 10%

0507 1911 2014 56.2 56.4 0.3 0 to 5%

0508 1900 2014 54.6 61.5 6.9 10 to 25%

0509 1899 2014 58.4 60.3 1.8 0 to 5%

0510 * 1898 2014 58.2 66.8 8.6 10 to 25%

0511 * 1897 2014 66.0 77.0 11.0 10 to 25%

0512 1895 2014 60.8 65.7 4.9 5 to 10%

0513 1896 2014 70.6 73.8 3.2 0 to 5%

0514 * 1895 2014 66.7 74.4 7.7 10 to 25%

0601 * 1898 2014 57.2 69.3 12.1 10 to 25%

0602 1896 2014 68.3 79.9 11.6 10 to 25%

0603 * 1898 2014 72.4 89.3 16.9 10 to 25%

0604 * 1901 2014 69.9 89.0 19.1 25 to 50%

0701 * 1893 2014 52.4 59.6 7.2 10 to 25%

0702 * 1896 2014 50.7 58.6 7.9 10 to 25%

0703 1907 2014 58.7 59.6 0.9 0 to 5%

0704 * 1896 2014 51.5 64.7 13.2 25 to 50%

0705 1905 2014 55.4 59.0 3.6 5 to 10%

0706 * 1904 2014 57.1 66.8 9.8 10 to 25%

0707 1905 2014 57.3 54.0 -3.3 -10 to -5%

0708 * 1895 2014 59.0 65.8 6.9 10 to 25%

0709 * 1896 2014 56.9 64.4 7.5 10 to 25%

0710 1899 2014 60.9 63.9 2.9 0 to 5%

0711 1896 2014 62.3 70.3 8.0 10 to 25%
MRG&P Report No. 34 152

HUC4 p < 0.05 

Year Rainfall [mm] Change in Rainfall 

Min Max Min Year Max Year [mm] %Change 

0712 * 1900 2014 51.7 68.5 16.8 25 to 50%

0713 1896 2014 58.7 64.4 5.8 5 to 10%

0714 1896 2014 66.8 70.7 3.9 5 to 10%

0801 1906 2014 77.6 87.2 9.6 10 to 25%

0802 1903 2014 79.6 83.7 4.1 5 to 10%

0803 1901 2014 84.2 92.3 8.2 5 to 10%

0804 * 1901 2014 85.6 99.0 13.3 10 to 25%

0805 * 1911 2014 85.5 100.1 14.7 10 to 25%

0806 1897 2014 95.7 99.3 3.6 0 to 5%

0807 * 1898 2014 93.1 117.5 24.5 25 to 50%

0808 * 1894 2014 97.1 118.3 21.2 10 to 25%

0809 * 1900 2014 97.3 121.3 24.0 10 to 25%

1002 1907 2014 26.2 23.9 -2.3 -10 to -5%

1003 1899 2014 30.5 30.2 -0.3 -5 to 0%

1004 1906 2014 30.8 34.7 4.0 10 to 25%

1005 1912 2014 31.3 33.9 2.6 5 to 10%

1006 1911 2014 33.5 37.0 3.6 10 to 25%

1007 1908 2014 31.6 33.1 1.5 0 to 5%

1008 1913 2014 25.6 26.3 0.7 0 to 5%

1009 1912 2014 32.1 35.3 3.3 10 to 25%

1010 1909 2014 33.3 36.0 2.7 5 to 10%

1011 1911 2014 37.6 40.6 3.0 5 to 10%

1012 1911 2014 38.9 40.4 1.6 0 to 5%

1013 1901 2014 40.4 43.1 2.7 5 to 10%

1014 1904 2014 44.6 46.7 2.1 0 to 5%

1015 * 1910 2014 40.1 48.6 8.5 10 to 25%

1016 1896 2014 47.7 49.0 1.3 0 to 5%

1017 1899 2014 51.7 56.5 4.8 5 to 10%

1018 1900 2014 34.9 32.4 -2.5 -10 to -5%

1019 1898 2014 36.3 38.9 2.6 5 to 10%
MRG&P Report No. 34 153

HUC4 p < 0.05 

Year Rainfall [mm] Change in Rainfall 

Min Max Min Year Max Year [mm] %Change 

1020 1902 2014 53.7 60.3 6.6 10 to 25%

1021 1897 2014 54.6 54.0 -0.6 -5 to 0%

1022 * 1899 2014 54.0 61.8 7.8 10 to 25%

1023 1897 2014 57.0 61.9 4.9 5 to 10%

1024 1896 2014 68.5 65.5 -3.0 -5 to 0%

1025 1893 2014 56.3 51.7 -4.5 -10 to -5%

1026 1900 2014 56.0 58.3 2.2 0 to 5%

1027 1894 2014 64.0 66.1 2.1 0 to 5%

1028 * 1894 2014 62.8 74.7 11.9 10 to 25%

1029 1897 2014 71.4 76.5 5.1 5 to 10%

1030 * 1895 2014 64.4 75.6 11.2 10 to 25%

1101 1897 2014 76.1 78.4 2.3 0 to 5%

1102 1897 2014 40.3 35.6 -4.7 -25 to -10%

1103 * 1901 2014 55.7 65.8 10.1 10 to 25%

1104 1903 2014 54.4 46.1 -8.4 -25 to -10%

1105 * 1900 2014 61.3 77.9 16.6 25 to 50%

1106 1910 2014 76.5 74.4 -2.2 -5 to 0%

1107 1895 2014 75.1 81.1 6.0 5 to 10%

1108 1905 2014 42.2 41.2 -1.0 -5 to 0%

1109 * 1907 2014 55.0 65.9 10.9 10 to 25%

1110 1909 2014 64.9 66.9 2.0 0 to 5%

1111 * 1892 2014 73.7 86.0 12.2 10 to 25%

1112 1908 2014 53.5 63.6 10.0 10 to 25%

1113 1901 2014 68.1 71.8 3.7 5 to 10%

1114 1903 2014 89.1 89.2 0.1 0 to 5%

 
MRG&P Report No. 34 154

Table E-3. Change in maximum annual 7-day rainfall total by HUC-4. 

HUC4 p < 0.05 

Year Rainfall [mm] Change in Rainfall 

Min Max Min Year Max Year [mm] %Change 

0501 1893 2014 795.3 857.6 62.3 5 to 10%

0502 1896 2014 841.4 866.6 25.2 0 to 5%

0503 1896 2014 800.7 844.7 44.0 5 to 10%

0504 1900 2014 797.7 861.6 64.0 5 to 10%

0505 1902 2014 857.1 920.9 63.8 5 to 10%

0506 1899 2014 846.2 877.6 31.4 0 to 5%

0507 1911 2014 946.7 915.2 -31.5 -5 to 0%

0508 1900 2014 907.7 936.1 28.4 0 to 5%

0509 1899 2014 908.9 980.2 71.3 5 to 10%

0510 1898 2014 994.7 1062.3 67.5 5 to 10%

0511 1897 2014 1127.2 1211.5 84.3 5 to 10%

0512 * 1895 2014 926.6 1034.7 108.1 10 to 25%

0513 1896 2014 1098.7 1218.9 120.2 10 to 25%

0514 1895 2014 1060.4 1171.7 111.4 10 to 25%

0601 * 1898 2014 939.8 1121.4 181.7 10 to 25%

0602 1896 2014 1174.1 1278.2 104.2 5 to 10%

0603 * 1898 2014 1170.8 1381.6 210.7 10 to 25%

0604 * 1901 2014 1158.8 1380.9 222.1 10 to 25%

0701 * 1893 2014 781.0 918.2 137.2 10 to 25%

0702 1896 2014 780.9 817.8 36.9 0 to 5%

0703 1907 2014 803.1 896.9 93.9 10 to 25%

0704 1896 2014 822.3 939.7 117.4 10 to 25%

0705 1905 2014 838.0 901.4 63.4 5 to 10%

0706 * 1904 2014 871.1 1040.6 169.5 10 to 25%

0707 1905 2014 891.2 829.1 -62.1 -10 to -5%

0708 1895 2014 890.3 965.7 75.4 5 to 10%

0709 1896 2014 882.5 958.9 76.5 5 to 10%

0710 1899 2014 923.4 951.8 28.4 0 to 5%

0711 1896 2014 955.8 1072.8 116.9 10 to 25%
MRG&P Report No. 34 155

HUC4 p < 0.05 

Year Rainfall [mm] Change in Rainfall 

Min Max Min Year Max Year [mm] %Change 

0712 * 1900 2014 782.3 1005.3 223.1 25 to 50%

0713 1896 2014 887.0 961.9 74.9 5 to 10%

0714 1896 2014 983.2 1095.5 112.2 10 to 25%

0801 1906 2014 1206.2 1375.4 169.1 10 to 25%

0802 1903 2014 1267.5 1263.2 -4.2 -5 to 0%

0803 1901 2014 1320.8 1415.4 94.6 5 to 10%

0804 1901 2014 1374.9 1515.6 140.7 10 to 25%

0805 1911 2014 1353.6 1493.9 140.4 10 to 25%

0806 1897 2014 1413.9 1561.8 147.9 10 to 25%

0807 * 1898 2014 1324.0 1740.2 416.2 25 to 50%

0808 * 1894 2014 1351.2 1744.2 392.9 25 to 50%

0809 * 1900 2014 1439.4 1774.3 334.9 10 to 25%

1002 1907 2014 444.1 396.5 -47.7 -25 to -10%

1003 1899 2014 483.6 492.1 8.5 0 to 5%

1004 1906 2014 493.4 547.6 54.3 10 to 25%

1005 1912 2014 492.0 476.8 -15.2 -5 to 0%

1006 1911 2014 480.4 553.3 72.9 10 to 25%

1007 1908 2014 463.2 542.2 79.1 10 to 25%

1008 1913 2014 373.1 403.2 30.1 5 to 10%

1009 1912 2014 469.6 526.5 56.9 10 to 25%

1010 * 1909 2014 463.2 560.6 97.3 10 to 25%

1011 1911 2014 562.2 588.4 26.2 0 to 5%

1012 1911 2014 585.8 611.8 26.1 0 to 5%

1013 1901 2014 575.4 642.0 66.5 10 to 25%

1014 1904 2014 616.6 682.5 65.9 10 to 25%

1015 1910 2014 603.4 691.2 87.7 10 to 25%

1016 1896 2014 681.7 713.2 31.5 0 to 5%

1017 1899 2014 805.2 817.2 12.0 0 to 5%

1018 1900 2014 529.4 458.7 -70.7 -25 to -10%

1019 1898 2014 551.2 582.0 30.8 5 to 10%
MRG&P Report No. 34 156

HUC4 p < 0.05 

Year Rainfall [mm] Change in Rainfall 

Min Max Min Year Max Year [mm] %Change 

1020 1902 2014 810.3 860.4 50.1 5 to 10%

1021 1897 2014 805.7 784.6 -21.1 -5 to 0%

1022 * 1899 2014 785.4 916.0 130.5 10 to 25%

1023 * 1897 2014 836.1 951.8 115.8 10 to 25%

1024 1896 2014 1037.7 973.7 -64.1 -10 to -5%

1025 1893 2014 802.7 749.2 -53.5 -10 to -5%

1026 1900 2014 825.0 807.9 -17.1 -5 to 0%

1027 1894 2014 978.5 936.5 -41.9 -5 to 0%

1028 1894 2014 973.3 1106.5 133.2 10 to 25%

1029 1897 2014 1046.1 1210.7 164.7 10 to 25%

1030 1895 2014 983.3 1166.8 183.5 10 to 25%

1101 1897 2014 1129.6 1228.8 99.2 5 to 10%

1102 * 1897 2014 600.4 493.1 -107.3 -25 to -10%

1103 * 1901 2014 820.9 989.7 168.8 10 to 25%

1104 1903 2014 766.2 680.8 -85.4 -25 to -10%

1105 1900 2014 1014.1 1026.5 12.4 0 to 5%

1106 1910 2014 1039.8 1067.5 27.7 0 to 5%

1107 1895 2014 1099.6 1253.1 153.5 10 to 25%

1108 1905 2014 618.9 621.9 3.0 0 to 5%

1109 * 1907 2014 805.7 927.4 121.6 10 to 25%

1110 1909 2014 968.6 958.8 -9.8 -5 to 0%

1111 1892 2014 1184.9 1304.6 119.7 10 to 25%

1112 1908 2014 840.4 923.8 83.5 5 to 10%

1113 1901 2014 1029.1 1027.3 -1.8 -5 to 0%

1114 1903 2014 1307.0 1353.5 46.6 0 to 5%

 
MRG&P Report No. 34 157

Table E-4. Change in winter rainfall by HUC-4. 

HUC4 p < 0.05 

Year Rainfall [mm] Change in Rainfall 

Min Max Min Year Max Year [mm] %Change 

0501 1893 2014 227.8 225.8 -2.1 -5 to 0%

0502 1896 2014 251.7 244.4 -7.2 -5 to 0%

0503 1896 2014 217.4 205.0 -12.4 -10 to -5%

0504 1900 2014 207.1 189.8 -17.3 -10 to -5%

0505 1902 2014 248.3 234.1 -14.1 -10 to -5%

0506 1899 2014 197.1 193.1 -3.9 -5 to 0%

0507 1911 2014 273.3 253.0 -20.3 -10 to -5%

0508 1900 2014 199.5 200.3 0.8 0 to 5%

0509 1899 2014 237.6 228.6 -9.0 -5 to 0%

0510 1898 2014 292.7 265.9 -26.8 -10 to -5%

0511 1897 2014 318.5 312.3 -6.2 -5 to 0%

0512 1895 2014 197.0 200.8 3.8 0 to 5%

0513 1896 2014 342.6 337.4 -5.1 -5 to 0%

0514 1895 2014 256.9 279.0 22.1 5 to 10%

0601 1898 2014 295.2 334.4 39.2 10 to 25%

0602 1896 2014 384.4 387.9 3.5 0 to 5%

0603 1898 2014 383.7 401.5 17.8 0 to 5%

0604 1901 2014 343.4 367.2 23.8 5 to 10%

0701 * 1893 2014 43.3 65.8 22.5 50 to 100%

0702 1896 2014 50.5 57.7 7.2 10 to 25%

0703 1907 2014 61.8 71.9 10.1 10 to 25%

0704 1896 2014 61.8 80.1 18.4 25 to 50%

0705 1905 2014 72.5 76.0 3.5 0 to 5%

0706 * 1904 2014 77.6 109.0 31.5 25 to 50%

0707 1905 2014 75.2 86.8 11.6 10 to 25%

0708 1895 2014 93.7 96.8 3.1 0 to 5%

0709 1896 2014 110.8 117.1 6.3 5 to 10%

0710 1899 2014 79.3 71.5 -7.8 -10 to -5%

0711 1896 2014 117.1 145.4 28.3 10 to 25%
MRG&P Report No. 34 158

HUC4 p < 0.05 

Year Rainfall [mm] Change in Rainfall 

Min Max Min Year Max Year [mm] %Change 

0712 1900 2014 129.7 153.9 24.2 10 to 25%

0713 * 1896 2014 120.8 155.9 35.1 25 to 50%

0714 1896 2014 175.7 204.0 28.3 10 to 25%

0801 1906 2014 333.5 356.3 22.8 5 to 10%

0802 1903 2014 314.7 304.0 -10.7 -5 to 0%

0803 1901 2014 373.0 393.0 20.0 5 to 10%

0804 1901 2014 355.5 350.8 -4.7 -5 to 0%

0805 1911 2014 368.3 403.3 35.0 5 to 10%

0806 1897 2014 393.3 412.4 19.1 0 to 5%

0807 1898 2014 413.9 386.7 -27.2 -10 to -5%

0808 1894 2014 398.3 382.8 -15.6 -5 to 0%

0809 1900 2014 340.0 363.8 23.8 5 to 10%

1002 * 1907 2014 51.4 30.6 -20.8 -50 to -25%

1003 * 1899 2014 40.0 29.2 -10.7 -50 to -25%

1004 1906 2014 36.9 34.2 -2.7 -10 to -5%

1005 * 1912 2014 32.7 23.0 -9.7 -50 to -25%

1006 1911 2014 23.8 22.8 -1.0 -5 to 0%

1007 1908 2014 40.9 44.0 3.0 5 to 10%

1008 1913 2014 21.1 24.2 3.1 10 to 25%

1009 * 1912 2014 42.3 30.7 -11.6 -50 to -25%

1010 1909 2014 27.9 30.1 2.2 5 to 10%

1011 1911 2014 30.0 33.7 3.8 10 to 25%

1012 1911 2014 37.1 29.5 -7.6 -25 to -10%

1013 1901 2014 28.7 29.8 1.1 0 to 5%

1014 1904 2014 33.0 34.8 1.7 5 to 10%

1015 1910 2014 34.2 31.5 -2.7 -10 to -5%

1016 1896 2014 36.2 35.5 -0.7 -5 to 0%

1017 1899 2014 51.4 45.8 -5.6 -25 to -10%

1018 1900 2014 35.4 31.3 -4.1 -25 to -10%

1019 1898 2014 36.3 32.6 -3.7 -25 to -10%
MRG&P Report No. 34 159

HUC4 p < 0.05 

Year Rainfall [mm] Change in Rainfall 

Min Max Min Year Max Year [mm] %Change 

1020 1902 2014 48.9 50.7 1.8 0 to 5%

1021 1897 2014 41.3 44.2 2.9 5 to 10%

1022 1899 2014 59.4 48.4 -11.0 -25 to -10%

1023 1897 2014 58.0 55.5 -2.5 -5 to 0%

1024 1896 2014 70.4 74.7 4.3 5 to 10%

1025 1893 2014 37.3 36.3 -1.0 -5 to 0%

1026 1900 2014 44.5 45.0 0.4 0 to 5%

1027 1894 2014 59.1 62.9 3.8 5 to 10%

1028 1894 2014 97.7 100.0 2.3 0 to 5%

1029 1897 2014 117.4 133.0 15.6 10 to 25%

1030 1895 2014 127.4 137.4 10.0 5 to 10%

1101 1897 2014 222.4 249.9 27.6 10 to 25%

1102 * 1897 2014 35.1 24.1 -11.0 -50 to -25%

1103 1901 2014 49.9 64.2 14.3 25 to 50%

1104 1903 2014 33.9 30.5 -3.4 -25 to -10%

1105 1900 2014 78.2 94.1 15.9 10 to 25%

1106 1910 2014 80.6 93.7 13.1 10 to 25%

1107 1895 2014 112.7 114.8 2.1 0 to 5%

1108 1905 2014 27.7 36.4 8.7 25 to 50%

1109 * 1907 2014 36.5 72.6 36.1 50 to 100%

1110 1909 2014 71.8 72.6 0.8 0 to 5%

1111 * 1892 2014 185.2 252.8 67.6 25 to 50%

1112 1908 2014 41.5 62.9 21.4 50 to 100%

1113 1901 2014 84.9 88.3 3.4 0 to 5%

1114 1903 2014 259.1 319.9 60.9 10 to 25%

 
MRG&P Report No. 34 160

Table E-5. Change in spring rainfall by HUC-4. 

HUC4 p < 0.05 

Year Rainfall [mm] Change in Rainfall 

Min Max Min Year Max Year [mm] %Change 

0501 1893 2014 267.3 285.4 18.1 5 to 10%

0502 1896 2014 288.8 313.7 25.0 5 to 10%

0503 1896 2014 263.9 278.0 14.2 5 to 10%

0504 1900 2014 268.7 275.4 6.7 0 to 5%

0505 1902 2014 281.8 303.9 22.1 5 to 10%

0506 1899 2014 263.4 279.4 16.0 5 to 10%

0507 1911 2014 286.6 320.5 33.9 10 to 25%

0508 1900 2014 270.7 290.2 19.5 5 to 10%

0509 1899 2014 282.6 319.8 37.2 10 to 25%

0510 1898 2014 304.2 344.2 40.0 10 to 25%

0511 1897 2014 332.7 371.1 38.4 10 to 25%

0512 1895 2014 279.5 308.9 29.3 10 to 25%

0513 1896 2014 341.6 372.3 30.7 5 to 10%

0514 * 1895 2014 300.8 362.8 62.0 10 to 25%

0601 * 1898 2014 305.2 351.5 46.3 10 to 25%

0602 1896 2014 376.6 366.8 -9.8 -5 to 0%

0603 1898 2014 363.4 395.2 31.8 5 to 10%

0604 1901 2014 343.2 412.0 68.8 10 to 25%

0701 1893 2014 156.9 189.8 32.9 10 to 25%

0702 1896 2014 162.6 195.5 32.9 10 to 25%

0703 1907 2014 160.9 210.4 49.5 25 to 50%

0704 1896 2014 191.7 224.3 32.6 10 to 25%

0705 1905 2014 181.9 222.1 40.2 10 to 25%

0706 1904 2014 221.0 257.8 36.8 10 to 25%

0707 1905 2014 193.2 209.1 15.9 5 to 10%

0708 * 1895 2014 220.9 264.9 44.0 10 to 25%

0709 1896 2014 226.8 245.0 18.2 5 to 10%

0710 * 1899 2014 202.5 258.2 55.6 25 to 50%

0711 1896 2014 255.1 288.5 33.4 10 to 25%
MRG&P Report No. 34 161

HUC4 p < 0.05 

Year Rainfall [mm] Change in Rainfall 

Min Max Min Year Max Year [mm] %Change 

0712 1900 2014 239.0 266.5 27.5 10 to 25%

0713 1896 2014 252.0 276.9 24.9 5 to 10%

0714 1896 2014 289.2 321.0 31.8 10 to 25%

0801 1906 2014 334.2 410.2 76.0 10 to 25%

0802 1903 2014 345.7 380.4 34.7 10 to 25%

0803 1901 2014 378.1 408.3 30.2 5 to 10%

0804 1901 2014 395.6 387.3 -8.3 -5 to 0%

0805 1911 2014 366.9 379.1 12.2 0 to 5%

0806 1897 2014 375.7 401.2 25.5 5 to 10%

0807 1898 2014 365.2 378.3 13.1 0 to 5%

0808 1894 2014 371.3 321.7 -49.5 -25 to -10%

0809 1900 2014 370.6 343.8 -26.8 -10 to -5%

1002 1907 2014 108.1 100.8 -7.3 -10 to -5%

1003 1899 2014 89.1 101.1 12.0 10 to 25%

1004 * 1906 2014 85.7 126.8 41.1 25 to 50%

1005 * 1912 2014 65.4 93.5 28.1 25 to 50%

1006 1911 2014 70.6 88.7 18.1 25 to 50%

1007 * 1908 2014 107.9 141.7 33.9 25 to 50%

1008 1913 2014 76.2 94.9 18.7 10 to 25%

1009 1912 2014 118.9 124.7 5.8 0 to 5%

1010 * 1909 2014 75.2 116.9 41.8 50 to 100%

1011 1911 2014 85.8 116.9 31.1 25 to 50%

1012 1911 2014 127.6 157.0 29.4 10 to 25%

1013 1901 2014 101.1 130.5 29.5 25 to 50%

1014 * 1904 2014 129.7 169.8 40.2 25 to 50%

1015 1910 2014 134.3 169.9 35.5 25 to 50%

1016 1896 2014 153.2 144.3 -8.9 -10 to -5%

1017 1899 2014 163.2 203.7 40.4 10 to 25%

1018 1900 2014 131.7 113.3 -18.4 -25 to -10%

1019 1898 2014 133.2 135.2 2.0 0 to 5%
MRG&P Report No. 34 162

HUC4 p < 0.05 

Year Rainfall [mm] Change in Rainfall 

Min Max Min Year Max Year [mm] %Change 

1020 * 1902 2014 164.9 232.0 67.2 25 to 50%

1021 1897 2014 175.8 194.3 18.5 10 to 25%

1022 1899 2014 181.3 224.4 43.1 10 to 25%

1023 * 1897 2014 178.3 232.4 54.1 25 to 50%

1024 1896 2014 217.3 255.9 38.6 10 to 25%

1025 1893 2014 161.2 168.4 7.2 0 to 5%

1026 1900 2014 166.3 183.5 17.1 10 to 25%

1027 * 1894 2014 192.9 242.6 49.7 25 to 50%

1028 * 1894 2014 235.5 287.2 51.8 10 to 25%

1029 1897 2014 273.2 304.1 30.9 10 to 25%

1030 1895 2014 267.9 299.8 32.0 10 to 25%

1101 1897 2014 328.2 340.4 12.2 0 to 5%

1102 1897 2014 119.9 90.6 -29.3 -25 to -10%

1103 * 1901 2014 168.6 216.4 47.8 25 to 50%

1104 1903 2014 137.0 119.5 -17.5 -25 to -10%

1105 1900 2014 219.8 246.1 26.3 10 to 25%

1106 1910 2014 209.7 271.4 61.7 25 to 50%

1107 1895 2014 280.9 305.0 24.1 5 to 10%

1108 1905 2014 87.9 93.8 6.0 5 to 10%

1109 * 1907 2014 128.9 198.4 69.5 50 to 100%

1110 1909 2014 205.2 188.1 -17.1 -10 to -5%

1111 1892 2014 325.8 359.3 33.6 10 to 25%

1112 1908 2014 134.1 180.0 46.0 25 to 50%

1113 1901 2014 217.8 214.1 -3.7 -5 to 0%

1114 1903 2014 349.5 347.2 -2.3 -5 to 0%

 
MRG&P Report No. 34 163

Table E-6. Change in summer rainfall by HUC-4. 

HUC4 p < 0.05 

Year Rainfall [mm] Change in Rainfall 

Min Max Min Year Max Year [mm] %Change 

0501 1893 2014 303.5 333.2 29.7 5 to 10%

0502 1896 2014 336.6 343.3 6.7 0 to 5%

0503 1896 2014 303.3 295.0 -8.3 -5 to 0%

0504 1900 2014 293.3 307.4 14.1 0 to 5%

0505 * 1902 2014 340.4 298.8 -41.6 -25 to -10%

0506 1899 2014 273.5 292.4 18.9 5 to 10%

0507 1911 2014 322.5 333.3 10.9 0 to 5%

0508 1900 2014 266.2 284.9 18.7 5 to 10%

0509 1899 2014 281.7 307.6 25.9 5 to 10%

0510 1898 2014 305.8 332.1 26.4 5 to 10%

0511 1897 2014 276.1 316.2 40.2 10 to 25%

0512 * 1895 2014 256.3 315.4 59.1 10 to 25%

0513 1896 2014 322.8 316.4 -6.4 -5 to 0%

0514 1895 2014 274.2 286.8 12.6 0 to 5%

0601 1898 2014 348.4 327.6 -20.8 -10 to -5%

0602 1896 2014 346.8 319.7 -27.1 -10 to -5%

0603 1898 2014 322.6 298.3 -24.3 -10 to -5%

0604 1901 2014 293.9 303.4 9.5 0 to 5%

0701 1893 2014 267.7 308.0 40.3 10 to 25%

0702 1896 2014 284.5 272.9 -11.6 -5 to 0%

0703 1907 2014 292.4 315.8 23.5 5 to 10%

0704 1896 2014 295.8 338.8 43.0 10 to 25%

0705 1905 2014 323.2 317.4 -5.8 -5 to 0%

0706 * 1904 2014 273.3 348.1 74.7 25 to 50%

0707 1905 2014 322.2 292.9 -29.2 -10 to -5%

0708 * 1895 2014 273.2 333.4 60.2 10 to 25%

0709 1896 2014 266.7 323.4 56.7 10 to 25%

0710 1899 2014 291.3 314.7 23.4 5 to 10%

0711 1896 2014 274.7 297.7 23.0 5 to 10%
MRG&P Report No. 34 164

HUC4 p < 0.05 

Year Rainfall [mm] Change in Rainfall 

Min Max Min Year Max Year [mm] %Change 

0712 * 1900 2014 231.3 323.4 92.1 25 to 50%

0713 1896 2014 252.5 291.8 39.3 10 to 25%

0714 1896 2014 271.0 274.8 3.8 0 to 5%

0801 1906 2014 274.1 290.7 16.6 5 to 10%

0802 1903 2014 281.3 242.7 -38.5 -25 to -10%

0803 1901 2014 269.6 279.6 10.0 0 to 5%

0804 1901 2014 285.9 291.2 5.2 0 to 5%

0805 1911 2014 265.4 264.4 -1.0 -5 to 0%

0806 1897 2014 341.5 297.8 -43.7 -25 to -10%

0807 1898 2014 427.8 415.3 -12.5 -5 to 0%

0808 1894 2014 395.3 391.1 -4.2 -5 to 0%

0809 1900 2014 479.1 474.5 -4.6 -5 to 0%

1002 1907 2014 122.8 113.7 -9.1 -10 to -5%

1003 1899 2014 129.2 126.8 -2.3 -5 to 0%

1004 1906 2014 145.3 146.6 1.3 0 to 5%

1005 1912 2014 151.2 125.4 -25.8 -25 to -10%

1006 1911 2014 151.5 163.0 11.5 5 to 10%

1007 1908 2014 113.0 121.0 7.9 5 to 10%

1008 1913 2014 77.2 63.8 -13.4 -25 to -10%

1009 1912 2014 124.6 111.9 -12.7 -25 to -10%

1010 1909 2014 148.3 130.5 -17.7 -25 to -10%

1011 1911 2014 181.7 167.6 -14.1 -10 to -5%

1012 1911 2014 171.1 165.0 -6.1 -5 to 0%

1013 1901 2014 189.0 188.7 -0.3 -5 to 0%

1014 1904 2014 188.9 196.4 7.6 0 to 5%

1015 1910 2014 177.6 213.3 35.6 10 to 25%

1016 1896 2014 226.1 216.3 -9.8 -5 to 0%

1017 1899 2014 264.6 242.6 -22.0 -10 to -5%

1018 1900 2014 123.3 111.0 -12.3 -10 to -5%

1019 * 1898 2014 129.0 161.8 32.8 25 to 50%
MRG&P Report No. 34 165

HUC4 p < 0.05 

Year Rainfall [mm] Change in Rainfall 

Min Max Min Year Max Year [mm] %Change 

1020 1902 2014 261.2 263.6 2.3 0 to 5%

1021 1897 2014 253.9 238.5 -15.4 -10 to -5%

1022 1899 2014 275.5 259.9 -15.6 -10 to -5%

1023 1897 2014 274.9 293.2 18.3 5 to 10%

1024 1896 2014 316.8 315.2 -1.6 -5 to 0%

1025 1893 2014 218.2 236.5 18.3 5 to 10%

1026 1900 2014 216.7 249.0 32.3 10 to 25%

1027 1894 2014 289.9 298.4 8.6 0 to 5%

1028 1894 2014 308.7 336.0 27.2 5 to 10%

1029 1897 2014 316.0 317.9 2.0 0 to 5%

1030 1895 2014 302.3 308.2 5.9 0 to 5%

1101 * 1897 2014 314.0 247.1 -66.9 -25 to -10%

1102 1897 2014 154.1 156.6 2.4 0 to 5%

1103 1901 2014 232.4 273.9 41.5 10 to 25%

1104 1903 2014 195.3 188.6 -6.7 -5 to 0%

1105 1900 2014 229.2 263.9 34.6 10 to 25%

1106 1910 2014 248.3 287.2 38.9 10 to 25%

1107 1895 2014 297.7 317.1 19.4 5 to 10%

1108 1905 2014 176.7 206.4 29.7 10 to 25%

1109 1907 2014 192.8 223.3 30.5 10 to 25%

1110 1909 2014 196.2 227.6 31.4 10 to 25%

1111 1892 2014 281.9 264.3 -17.6 -10 to -5%

1112 1908 2014 184.6 217.1 32.5 10 to 25%

1113 1901 2014 192.1 213.2 21.1 10 to 25%

1114 1903 2014 238.0 267.0 29.0 10 to 25%

 
MRG&P Report No. 34 166

Table E-7. Change in fall rainfall by HUC-4. 

HUC4 p < 0.05 

Year Rainfall [mm] Change in Rainfall 

Min Max Min Year Max Year [mm] %Change 

0501 * 1893 2014 212.9 289.7 76.8 25 to 50%

0502 * 1896 2014 207.5 267.0 59.6 25 to 50%

0503 * 1896 2014 192.5 238.8 46.2 10 to 25%

0504 * 1900 2014 188.6 234.3 45.7 10 to 25%

0505 1902 2014 214.1 243.4 29.2 10 to 25%

0506 1899 2014 183.6 220.6 37.0 10 to 25%

0507 1911 2014 206.2 247.3 41.2 10 to 25%

0508 1900 2014 202.2 230.3 28.2 10 to 25%

0509 * 1899 2014 187.7 244.9 57.2 25 to 50%

0510 * 1898 2014 203.1 262.1 58.9 25 to 50%

0511 * 1897 2014 204.0 299.4 95.4 25 to 50%

0512 1895 2014 221.0 252.0 31.0 10 to 25%

0513 * 1896 2014 221.4 298.7 77.3 25 to 50%

0514 * 1895 2014 215.8 279.1 63.2 25 to 50%

0601 * 1898 2014 199.2 280.0 80.8 25 to 50%

0602 * 1896 2014 198.2 331.2 133.0 50 to 100%

0603 * 1898 2014 224.2 322.3 98.1 25 to 50%

0604 * 1901 2014 211.9 326.6 114.7 50 to 100%

0701 1893 2014 141.4 169.4 28.0 10 to 25%

0702 1896 2014 135.4 153.6 18.2 10 to 25%

0703 1907 2014 150.2 201.6 51.4 25 to 50%

0704 1896 2014 170.3 189.2 19.0 10 to 25%

0705 1905 2014 188.7 202.8 14.1 5 to 10%

0706 1904 2014 207.5 198.5 -9.0 -5 to 0%

0707 1905 2014 192.1 217.6 25.5 10 to 25%

0708 1895 2014 196.0 201.9 5.9 0 to 5%

0709 1896 2014 210.0 203.7 -6.4 -5 to 0%

0710 1899 2014 195.5 166.2 -29.4 -25 to -10%

0711 1896 2014 222.4 237.6 15.1 5 to 10%
MRG&P Report No. 34 167

HUC4 p < 0.05 

Year Rainfall [mm] Change in Rainfall 

Min Max Min Year Max Year [mm] %Change 

0712 1900 2014 197.6 223.2 25.6 10 to 25%

0713 1896 2014 195.7 234.0 38.3 10 to 25%

0714 1896 2014 224.6 262.0 37.4 10 to 25%

0801 * 1906 2014 236.7 313.2 76.5 25 to 50%

0802 1903 2014 240.8 295.6 54.8 10 to 25%

0803 * 1901 2014 205.3 325.9 120.6 50 to 100%

0804 * 1901 2014 205.8 360.3 154.5 50 to 100%

0805 * 1911 2014 216.4 322.1 105.8 25 to 50%

0806 * 1897 2014 187.0 335.6 148.6 50 to 100%

0807 * 1898 2014 237.9 341.4 103.5 25 to 50%

0808 * 1894 2014 235.2 375.0 139.8 50 to 100%

0809 1900 2014 318.1 323.2 5.1 0 to 5%

1002 1907 2014 82.1 67.1 -15.0 -25 to -10%

1003 1899 2014 64.0 57.0 -7.1 -25 to -10%

1004 1906 2014 71.3 63.8 -7.4 -25 to -10%

1005 1912 2014 55.6 50.6 -5.0 -10 to -5%

1006 1911 2014 54.5 58.4 3.9 5 to 10%

1007 1908 2014 85.7 85.3 -0.4 -5 to 0%

1008 1913 2014 54.5 57.4 2.9 5 to 10%

1009 1912 2014 72.6 73.1 0.5 0 to 5%

1010 1909 2014 54.3 71.6 17.3 25 to 50%

1011 1911 2014 59.9 78.0 18.1 25 to 50%

1012 1911 2014 73.1 74.5 1.5 0 to 5%

1013 1901 2014 66.8 74.0 7.3 10 to 25%

1014 1904 2014 70.0 91.4 21.4 25 to 50%

1015 1910 2014 70.1 94.8 24.8 25 to 50%

1016 1896 2014 88.7 109.1 20.4 10 to 25%

1017 1899 2014 117.1 148.3 31.2 25 to 50%

1018 1900 2014 65.1 67.6 2.4 0 to 5%

1019 1898 2014 65.2 79.4 14.2 10 to 25%
MRG&P Report No. 34 168

HUC4 p < 0.05 

Year Rainfall [mm] Change in Rainfall 

Min Max Min Year Max Year [mm] %Change 

1020 1902 2014 127.4 139.4 12.0 5 to 10%

1021 1897 2014 101.8 123.0 21.3 10 to 25%

1022 1899 2014 124.3 146.9 22.6 10 to 25%

1023 1897 2014 146.6 158.8 12.3 5 to 10%

1024 1896 2014 200.8 183.3 -17.5 -10 to -5%

1025 1893 2014 94.5 98.9 4.3 0 to 5%

1026 1900 2014 117.9 114.0 -3.9 -5 to 0%

1027 1894 2014 155.2 175.8 20.6 10 to 25%

1028 1894 2014 210.1 232.3 22.2 10 to 25%

1029 1897 2014 236.2 267.1 30.9 10 to 25%

1030 1895 2014 226.6 261.9 35.3 10 to 25%

1101 * 1897 2014 232.4 308.2 75.8 25 to 50%

1102 1897 2014 67.0 61.0 -5.9 -10 to -5%

1103 1901 2014 141.3 141.1 -0.3 -5 to 0%

1104 1903 2014 93.1 82.9 -10.1 -25 to -10%

1105 1900 2014 186.9 175.9 -11.0 -10 to -5%

1106 1910 2014 183.8 190.2 6.3 0 to 5%

1107 1895 2014 233.8 257.1 23.3 5 to 10%

1108 1905 2014 77.4 91.7 14.3 10 to 25%

1109 * 1907 2014 100.7 160.6 60.0 50 to 100%

1110 1909 2014 164.6 146.7 -17.9 -25 to -10%

1111 * 1892 2014 221.2 332.2 111.0 50 to 100%

1112 1908 2014 128.4 137.4 9.0 5 to 10%

1113 1901 2014 168.0 187.6 19.6 10 to 25%

1114 * 1903 2014 196.4 340.7 144.4 50 to 100%
MRG&P Report No. 34 169

 

Table E-8. Change in maximum daily winter rainfall by HUC-4. 

HUC4 p < 0.05 

Year Rainfall [mm] Change in Rainfall 

Min Max Min Year Max Year [mm] %Change 

0501 1893 2014 26.3 27.3 1.0 0 to 5%

0502 1896 2014 31.0 29.0 -2.0 -10 to -5%

0503 1896 2014 26.8 29.3 2.5 5 to 10%

0504 1900 2014 27.1 30.3 3.2 10 to 25%

0505 1902 2014 29.7 34.2 4.6 10 to 25%

0506 1899 2014 27.2 31.3 4.0 10 to 25%

0507 1911 2014 34.1 35.2 1.1 0 to 5%

0508 1900 2014 31.7 33.3 1.5 0 to 5%

0509 1899 2014 34.4 35.1 0.7 0 to 5%

0510 1898 2014 38.8 41.6 2.8 5 to 10%

0511 1897 2014 44.4 51.1 6.7 10 to 25%

0512 1895 2014 34.4 34.2 -0.2 -5 to 0%

0513 1896 2014 51.4 48.9 -2.5 -5 to 0%

0514 1895 2014 43.1 45.8 2.8 5 to 10%

0601 * 1898 2014 37.7 49.9 12.2 25 to 50%

0602 1896 2014 50.1 56.3 6.2 10 to 25%

0603 1898 2014 54.2 62.5 8.3 10 to 25%

0604 1901 2014 48.7 56.8 8.2 10 to 25%

0701 * 1893 2014 10.5 14.1 3.6 25 to 50%

0702 1896 2014 12.9 14.4 1.5 10 to 25%

0703 1907 2014 12.4 15.5 3.1 25 to 50%

0704 1896 2014 15.6 15.3 -0.2 -5 to 0%

0705 1905 2014 16.2 15.8 -0.5 -5 to 0%

0706 1904 2014 17.4 21.6 4.2 10 to 25%

0707 1905 2014 16.1 15.0 -1.1 -10 to -5%

0708 1895 2014 21.3 20.0 -1.4 -10 to -5%

0709 1896 2014 21.9 22.1 0.2 0 to 5%

0710 * 1899 2014 19.6 15.8 -3.7 -25 to -10%
MRG&P Report No. 34 170

HUC4 p < 0.05 

Year Rainfall [mm] Change in Rainfall 

Min Max Min Year Max Year [mm] %Change 

0711 1896 2014 25.3 31.4 6.1 10 to 25%

0712 1900 2014 23.0 28.9 6.0 25 to 50%

0713 * 1896 2014 24.3 32.3 8.0 25 to 50%

0714 1896 2014 33.8 38.4 4.5 10 to 25%

0801 1906 2014 56.4 57.2 0.9 0 to 5%

0802 1903 2014 53.9 54.3 0.4 0 to 5%

0803 1901 2014 56.7 58.9 2.2 0 to 5%

0804 1901 2014 55.3 62.4 7.2 10 to 25%

0805 1911 2014 59.6 61.2 1.6 0 to 5%

0806 1897 2014 66.9 62.5 -4.4 -10 to -5%

0807 1898 2014 64.8 68.0 3.3 5 to 10%

0808 1894 2014 66.6 70.3 3.7 5 to 10%

0809 1900 2014 65.3 65.9 0.6 0 to 5%

1002 * 1907 2014 10.0 6.4 -3.5 -50 to -25%

1003 * 1899 2014 9.0 6.3 -2.7 -50 to -25%

1004 1906 2014 7.3 7.7 0.4 0 to 5%

1005 * 1912 2014 7.4 5.3 -2.1 -50 to -25%

1006 1911 2014 5.6 6.2 0.6 10 to 25%

1007 1908 2014 9.5 8.9 -0.6 -10 to -5%

1008 1913 2014 6.4 6.4 0.0 -5 to 0%

1009 1912 2014 8.9 6.8 -2.0 -25 to -10%

1010 1909 2014 7.2 6.4 -0.7 -10 to -5%

1011 1911 2014 7.0 6.9 -0.1 -5 to 0%

1012 * 1911 2014 9.1 6.8 -2.3 -50 to -25%

1013 1901 2014 7.3 7.2 -0.1 -5 to 0%

1014 1904 2014 10.9 8.9 -2.0 -25 to -10%

1015 1910 2014 8.2 9.5 1.3 10 to 25%

1016 1896 2014 10.6 9.6 -0.9 -10 to -5%

1017 1899 2014 12.7 13.3 0.6 0 to 5%

1018 * 1900 2014 9.4 7.0 -2.4 -50 to -25%
MRG&P Report No. 34 171

HUC4 p < 0.05 

Year Rainfall [mm] Change in Rainfall 

Min Max Min Year Max Year [mm] %Change 

1019 * 1898 2014 10.0 8.0 -2.0 -25 to -10%

1020 1902 2014 13.5 13.7 0.1 0 to 5%

1021 1897 2014 12.1 12.7 0.5 0 to 5%

1022 1899 2014 16.1 13.8 -2.3 -25 to -10%

1023 1897 2014 16.2 14.7 -1.5 -10 to -5%

1024 1896 2014 19.8 17.8 -2.0 -25 to -10%

1025 1893 2014 12.0 11.4 -0.6 -5 to 0%

1026 1900 2014 14.4 14.1 -0.3 -5 to 0%

1027 1894 2014 17.5 16.7 -0.8 -5 to 0%

1028 1894 2014 23.6 23.4 -0.2 -5 to 0%

1029 1897 2014 27.0 32.2 5.2 10 to 25%

1030 1895 2014 26.1 32.3 6.2 10 to 25%

1101 1897 2014 43.6 48.8 5.2 10 to 25%

1102 * 1897 2014 11.3 7.3 -4.1 -50 to -25%

1103 1901 2014 15.8 18.9 3.1 10 to 25%

1104 1903 2014 13.0 9.8 -3.2 -25 to -10%

1105 1900 2014 23.7 26.7 2.9 10 to 25%

1106 1910 2014 23.7 27.4 3.7 10 to 25%

1107 1895 2014 26.2 30.7 4.5 10 to 25%

1108 1905 2014 10.3 11.1 0.8 5 to 10%

1109 * 1907 2014 12.3 23.8 11.5 50 to 100%

1110 1909 2014 20.6 23.1 2.5 10 to 25%

1111 1892 2014 41.8 48.9 7.1 10 to 25%

1112 1908 2014 14.6 19.7 5.1 25 to 50%

1113 1901 2014 25.5 25.1 -0.4 -5 to 0%

1114 1903 2014 51.4 54.4 3.0 5 to 10%

 
MRG&P Report No. 34 172

Table E-9. Change in maximum daily spring rainfall by HUC-4. 

HUC4 p < 0.05 

Year Rainfall [mm] Change in Rainfall 

Min Max Min Year Max Year [mm] %Change 

0501 * 1893 2014 29.0 34.2 5.1 10 to 25%

0502 1896 2014 33.3 35.1 1.8 5 to 10%

0503 1896 2014 32.0 33.0 1.0 0 to 5%

0504 1900 2014 35.1 33.7 -1.5 -5 to 0%

0505 * 1902 2014 32.1 39.0 6.9 10 to 25%

0506 1899 2014 36.0 35.5 -0.5 -5 to 0%

0507 1911 2014 34.5 40.2 5.7 10 to 25%

0508 1900 2014 36.7 39.2 2.5 5 to 10%

0509 1899 2014 41.2 39.2 -2.0 -5 to 0%

0510 1898 2014 42.5 43.5 1.0 0 to 5%

0511 1897 2014 46.4 53.3 6.9 10 to 25%

0512 1895 2014 39.6 44.3 4.7 10 to 25%

0513 1896 2014 48.2 51.4 3.2 5 to 10%

0514 1895 2014 44.7 51.9 7.2 10 to 25%

0601 * 1898 2014 40.6 48.4 7.8 10 to 25%

0602 1896 2014 52.3 54.8 2.4 0 to 5%

0603 1898 2014 56.1 59.9 3.8 5 to 10%

0604 * 1901 2014 50.7 62.6 11.9 10 to 25%

0701 1893 2014 29.2 29.3 0.2 0 to 5%

0702 1896 2014 29.0 32.8 3.8 10 to 25%

0703 1907 2014 29.5 34.0 4.5 10 to 25%

0704 1896 2014 31.9 34.6 2.6 5 to 10%

0705 1905 2014 32.9 32.3 -0.6 -5 to 0%

0706 * 1904 2014 32.8 41.6 8.9 25 to 50%

0707 1905 2014 31.9 32.2 0.2 0 to 5%

0708 1895 2014 35.7 40.6 5.0 10 to 25%

0709 1896 2014 34.1 38.5 4.3 10 to 25%

0710 1899 2014 36.8 38.9 2.1 5 to 10%

0711 1896 2014 40.0 44.6 4.5 10 to 25%
MRG&P Report No. 34 173

HUC4 p < 0.05 

Year Rainfall [mm] Change in Rainfall 

Min Max Min Year Max Year [mm] %Change 

0712 * 1900 2014 34.2 40.7 6.5 10 to 25%

0713 1896 2014 37.2 42.4 5.2 10 to 25%

0714 1896 2014 42.1 48.0 5.9 10 to 25%

0801 1906 2014 52.9 62.3 9.4 10 to 25%

0802 1903 2014 54.7 59.5 4.8 5 to 10%

0803 1901 2014 60.0 68.1 8.1 10 to 25%

0804 1901 2014 66.3 68.2 1.9 0 to 5%

0805 1911 2014 65.8 69.4 3.6 5 to 10%

0806 1897 2014 70.9 68.1 -2.9 -5 to 0%

0807 1898 2014 67.1 79.8 12.7 10 to 25%

0808 1894 2014 70.4 71.7 1.3 0 to 5%

0809 1900 2014 72.7 75.7 3.0 0 to 5%

1002 1907 2014 18.3 16.9 -1.4 -10 to -5%

1003 1899 2014 17.7 20.8 3.0 10 to 25%

1004 * 1906 2014 18.4 23.8 5.4 25 to 50%

1005 * 1912 2014 15.5 21.5 6.0 25 to 50%

1006 1911 2014 17.1 20.8 3.7 10 to 25%

1007 1908 2014 22.7 24.4 1.7 5 to 10%

1008 1913 2014 17.9 19.9 2.0 10 to 25%

1009 1912 2014 22.5 24.0 1.5 5 to 10%

1010 1909 2014 17.8 23.0 5.2 25 to 50%

1011 1911 2014 19.7 24.7 5.0 25 to 50%

1012 1911 2014 25.8 28.8 3.0 10 to 25%

1013 * 1901 2014 21.4 27.7 6.3 25 to 50%

1014 1904 2014 28.0 31.7 3.7 10 to 25%

1015 1910 2014 27.2 33.3 6.1 10 to 25%

1016 1896 2014 30.1 28.4 -1.6 -10 to -5%

1017 1899 2014 30.2 35.7 5.5 10 to 25%

1018 1900 2014 25.9 21.5 -4.3 -25 to -10%

1019 1898 2014 25.8 26.7 0.9 0 to 5%
MRG&P Report No. 34 174

HUC4 p < 0.05 

Year Rainfall [mm] Change in Rainfall 

Min Max Min Year Max Year [mm] %Change 

1020 1902 2014 33.2 38.5 5.3 10 to 25%

1021 1897 2014 35.6 35.5 -0.1 -5 to 0%

1022 1899 2014 38.6 36.9 -1.7 -5 to 0%

1023 * 1897 2014 31.7 39.0 7.3 10 to 25%

1024 1896 2014 37.4 42.7 5.3 10 to 25%

1025 1893 2014 33.3 33.2 -0.1 -5 to 0%

1026 1900 2014 32.8 37.0 4.2 10 to 25%

1027 1894 2014 36.8 42.4 5.7 10 to 25%

1028 1894 2014 39.5 42.6 3.0 5 to 10%

1029 1897 2014 44.7 50.8 6.1 10 to 25%

1030 1895 2014 41.2 46.9 5.7 10 to 25%

1101 1897 2014 52.0 54.8 2.8 5 to 10%

1102 1897 2014 25.7 21.4 -4.3 -25 to -10%

1103 * 1901 2014 34.4 43.0 8.5 10 to 25%

1104 1903 2014 33.2 27.3 -6.0 -25 to -10%

1105 * 1900 2014 43.4 54.1 10.7 10 to 25%

1106 1910 2014 43.0 50.8 7.9 10 to 25%

1107 1895 2014 50.5 52.2 1.7 0 to 5%

1108 1905 2014 23.8 24.8 1.0 0 to 5%

1109 * 1907 2014 34.5 43.2 8.7 25 to 50%

1110 1909 2014 45.2 42.1 -3.0 -10 to -5%

1111 1892 2014 54.7 58.6 3.9 5 to 10%

1112 1908 2014 35.3 40.9 5.6 10 to 25%

1113 1901 2014 45.1 48.0 2.9 5 to 10%

1114 1903 2014 61.0 62.0 1.0 0 to 5%

 
MRG&P Report No. 34 175

Table E-10. Change in maximum daily summer rainfall by HUC-4. 

HUC4 p < 0.05 

Year Rainfall [mm] Change in Rainfall 

Min Max Min Year Max Year [mm] %Change 

0501 1893 2014 43.7 44.7 1.0 0 to 5%

0502 1896 2014 44.1 45.1 1.0 0 to 5%

0503 1896 2014 44.2 44.1 -0.1 -5 to 0%

0504 1900 2014 42.3 46.7 4.5 10 to 25%

0505 1902 2014 46.8 41.9 -4.9 -25 to -10%

0506 1899 2014 41.8 47.0 5.2 10 to 25%

0507 1911 2014 42.4 46.6 4.2 5 to 10%

0508 1900 2014 41.7 48.5 6.7 10 to 25%

0509 1899 2014 43.8 49.3 5.5 10 to 25%

0510 1898 2014 45.3 51.0 5.7 10 to 25%

0511 1897 2014 48.6 51.6 3.0 5 to 10%

0512 * 1895 2014 43.8 51.8 8.0 10 to 25%

0513 1896 2014 47.8 49.7 1.9 0 to 5%

0514 1895 2014 47.6 51.1 3.4 5 to 10%

0601 1898 2014 44.4 46.9 2.4 5 to 10%

0602 1896 2014 46.4 50.7 4.4 5 to 10%

0603 1898 2014 47.8 53.5 5.7 10 to 25%

0604 1901 2014 47.1 53.6 6.4 10 to 25%

0701 1893 2014 46.4 52.5 6.1 10 to 25%

0702 1896 2014 46.2 50.8 4.6 5 to 10%

0703 1907 2014 56.5 49.1 -7.4 -25 to -10%

0704 1896 2014 47.3 55.3 8.0 10 to 25%

0705 1905 2014 52.4 49.2 -3.1 -10 to -5%

0706 1904 2014 51.4 55.0 3.6 5 to 10%

0707 1905 2014 48.7 47.6 -1.1 -5 to 0%

0708 1895 2014 51.1 53.6 2.5 0 to 5%

0709 1896 2014 47.8 53.7 5.9 10 to 25%

0710 1899 2014 49.7 55.6 6.0 10 to 25%

0711 1896 2014 47.2 56.6 9.4 10 to 25%
MRG&P Report No. 34 176

HUC4 p < 0.05 

Year Rainfall [mm] Change in Rainfall 

Min Max Min Year Max Year [mm] %Change 

0712 * 1900 2014 44.8 54.5 9.7 10 to 25%

0713 1896 2014 47.3 49.8 2.5 5 to 10%

0714 1896 2014 48.5 51.5 2.9 5 to 10%

0801 1906 2014 51.8 54.9 3.1 5 to 10%

0802 1903 2014 54.2 47.3 -6.8 -25 to -10%

0803 1901 2014 48.0 54.3 6.3 10 to 25%

0804 1901 2014 51.2 57.8 6.6 10 to 25%

0805 1911 2014 48.2 53.9 5.7 10 to 25%

0806 1897 2014 53.2 54.6 1.4 0 to 5%

0807 1898 2014 58.4 60.5 2.2 0 to 5%

0808 1894 2014 60.6 61.8 1.2 0 to 5%

0809 1900 2014 60.8 67.8 7.0 10 to 25%

1002 1907 2014 19.8 20.1 0.3 0 to 5%

1003 1899 2014 24.1 25.4 1.3 5 to 10%

1004 1906 2014 26.6 28.5 1.8 5 to 10%

1005 1912 2014 28.7 27.0 -1.7 -10 to -5%

1006 1911 2014 29.6 31.7 2.2 5 to 10%

1007 1908 2014 22.4 21.8 -0.6 -5 to 0%

1008 1913 2014 19.8 15.3 -4.5 -25 to -10%

1009 1912 2014 27.8 23.7 -4.1 -25 to -10%

1010 1909 2014 29.0 26.1 -2.9 -10 to -5%

1011 1911 2014 35.3 31.9 -3.4 -10 to -5%

1012 1911 2014 31.3 31.3 0.0 0 to 5%

1013 1901 2014 36.2 34.7 -1.5 -5 to 0%

1014 1904 2014 35.1 38.7 3.6 10 to 25%

1015 * 1910 2014 33.2 39.7 6.5 10 to 25%

1016 1896 2014 40.5 42.6 2.1 5 to 10%

1017 1899 2014 45.4 46.9 1.4 0 to 5%

1018 1900 2014 25.4 23.2 -2.3 -10 to -5%

1019 1898 2014 25.5 30.2 4.7 10 to 25%
MRG&P Report No. 34 177

HUC4 p < 0.05 

Year Rainfall [mm] Change in Rainfall 

Min Max Min Year Max Year [mm] %Change 

1020 1902 2014 46.9 50.6 3.7 5 to 10%

1021 1897 2014 44.5 44.6 0.1 0 to 5%

1022 1899 2014 44.8 53.4 8.6 10 to 25%

1023 1897 2014 48.4 53.3 4.9 10 to 25%

1024 1896 2014 53.4 57.6 4.2 5 to 10%

1025 1893 2014 45.5 43.4 -2.1 -5 to 0%

1026 1900 2014 44.9 48.4 3.5 5 to 10%

1027 1894 2014 53.3 55.1 1.8 0 to 5%

1028 1894 2014 54.4 58.2 3.8 5 to 10%

1029 1897 2014 57.5 57.1 -0.3 -5 to 0%

1030 1895 2014 50.0 58.1 8.1 10 to 25%

1101 1897 2014 53.6 48.9 -4.7 -10 to -5%

1102 1897 2014 30.6 30.3 -0.4 -5 to 0%

1103 * 1901 2014 44.2 53.6 9.4 10 to 25%

1104 1903 2014 40.6 39.7 -0.9 -5 to 0%

1105 1900 2014 48.6 55.6 7.0 10 to 25%

1106 1910 2014 55.5 54.3 -1.2 -5 to 0%

1107 1895 2014 53.6 62.5 8.9 10 to 25%

1108 1905 2014 32.4 34.2 1.7 5 to 10%

1109 1907 2014 43.0 45.4 2.4 5 to 10%

1110 1909 2014 45.1 46.9 1.9 0 to 5%

1111 1892 2014 51.9 53.0 1.1 0 to 5%

1112 1908 2014 43.3 45.1 1.9 0 to 5%

1113 1901 2014 45.3 48.6 3.3 5 to 10%

1114 1903 2014 49.4 57.2 7.8 10 to 25%

 
MRG&P Report No. 34 178

Table E-11. Change in maximum daily fall rainfall by HUC-4. 

HUC4 p < 0.05 

Year Rainfall [mm] Change in Rainfall 

Min Max Min Year Max Year [mm] %Change 

0501 * 1893 2014 32.3 39.7 7.5 10 to 25%

0502 1896 2014 36.3 36.1 -0.2 -5 to 0%

0503 1896 2014 32.4 34.9 2.5 5 to 10%

0504 1900 2014 31.5 37.5 6.0 10 to 25%

0505 1902 2014 35.8 41.6 5.8 10 to 25%

0506 1899 2014 30.9 37.1 6.2 10 to 25%

0507 1911 2014 36.1 38.1 2.0 5 to 10%

0508 1900 2014 36.8 39.1 2.3 5 to 10%

0509 1899 2014 33.9 41.1 7.2 10 to 25%

0510 1898 2014 38.9 44.2 5.2 10 to 25%

0511 * 1897 2014 41.1 51.9 10.9 25 to 50%

0512 1895 2014 40.6 44.5 3.8 5 to 10%

0513 1896 2014 45.7 49.6 3.9 5 to 10%

0514 1895 2014 41.3 49.2 7.9 10 to 25%

0601 * 1898 2014 36.7 49.4 12.6 25 to 50%

0602 * 1896 2014 40.7 56.2 15.5 25 to 50%

0603 * 1898 2014 42.6 60.3 17.6 25 to 50%

0604 * 1901 2014 42.1 58.8 16.6 25 to 50%

0701 1893 2014 31.5 34.7 3.2 10 to 25%

0702 1896 2014 29.8 33.9 4.1 10 to 25%

0703 1907 2014 33.6 38.5 4.9 10 to 25%

0704 1896 2014 34.9 38.1 3.2 5 to 10%

0705 1905 2014 31.8 39.8 8.0 25 to 50%

0706 1904 2014 40.9 37.9 -3.0 -10 to -5%

0707 1905 2014 39.1 36.5 -2.7 -10 to -5%

0708 1895 2014 40.5 39.1 -1.5 -5 to 0%

0709 1896 2014 41.3 37.9 -3.4 -10 to -5%

0710 1899 2014 41.5 34.6 -6.9 -25 to -10%

0711 1896 2014 44.6 44.1 -0.4 -5 to 0%
MRG&P Report No. 34 179

HUC4 p < 0.05 

Year Rainfall [mm] Change in Rainfall 

Min Max Min Year Max Year [mm] %Change 

0712 1900 2014 34.9 41.8 6.9 10 to 25%

0713 1896 2014 38.5 42.2 3.7 5 to 10%

0714 1896 2014 45.1 45.8 0.7 0 to 5%

0801 * 1906 2014 48.4 58.1 9.7 10 to 25%

0802 1903 2014 51.7 56.5 4.8 5 to 10%

0803 * 1901 2014 47.6 64.2 16.6 25 to 50%

0804 * 1901 2014 50.6 72.5 22.0 25 to 50%

0805 * 1911 2014 49.4 69.4 20.0 25 to 50%

0806 * 1897 2014 42.6 72.6 29.9 50 to 100%

0807 * 1898 2014 48.4 79.3 30.9 50 to 100%

0808 * 1894 2014 51.3 83.3 32.1 50 to 100%

0809 1900 2014 65.7 72.5 6.9 10 to 25%

1002 1907 2014 17.4 14.1 -3.3 -25 to -10%

1003 1899 2014 15.9 14.0 -1.9 -25 to -10%

1004 1906 2014 16.9 15.3 -1.6 -10 to -5%

1005 1912 2014 14.9 13.4 -1.5 -10 to -5%

1006 1911 2014 16.6 16.0 -0.6 -5 to 0%

1007 1908 2014 20.3 18.3 -2.0 -10 to -5%

1008 1913 2014 14.3 16.3 2.0 10 to 25%

1009 1912 2014 17.2 17.9 0.7 0 to 5%

1010 1909 2014 15.6 17.8 2.2 10 to 25%

1011 1911 2014 16.2 20.8 4.6 25 to 50%

1012 1911 2014 18.7 19.7 1.0 5 to 10%

1013 1901 2014 18.4 20.6 2.2 10 to 25%

1014 1904 2014 19.9 25.6 5.7 25 to 50%

1015 * 1910 2014 19.1 24.5 5.4 25 to 50%

1016 1896 2014 24.5 27.1 2.6 10 to 25%

1017 1899 2014 28.1 34.8 6.7 10 to 25%

1018 1900 2014 17.9 16.3 -1.6 -10 to -5%

1019 1898 2014 17.8 19.4 1.6 5 to 10%
MRG&P Report No. 34 180

HUC4 p < 0.05 

Year Rainfall [mm] Change in Rainfall 

Min Max Min Year Max Year [mm] %Change 

1020 1902 2014 35.0 31.8 -3.2 -10 to -5%

1021 1897 2014 31.4 29.2 -2.2 -10 to -5%

1022 1899 2014 34.5 34.1 -0.4 -5 to 0%

1023 1897 2014 34.9 34.6 -0.3 -5 to 0%

1024 1896 2014 46.4 39.4 -7.0 -25 to -10%

1025 1893 2014 31.0 25.2 -5.7 -25 to -10%

1026 1900 2014 31.6 32.6 0.9 0 to 5%

1027 1894 2014 39.2 40.3 1.1 0 to 5%

1028 1894 2014 44.8 48.7 4.0 5 to 10%

1029 1897 2014 51.7 51.2 -0.5 -5 to 0%

1030 1895 2014 48.0 49.2 1.3 0 to 5%

1101 * 1897 2014 45.1 59.0 13.9 25 to 50%

1102 1897 2014 18.4 17.5 -0.9 -5 to 0%

1103 1901 2014 35.5 38.7 3.2 5 to 10%

1104 1903 2014 31.3 24.3 -7.1 -25 to -10%

1105 1900 2014 41.7 49.9 8.2 10 to 25%

1106 1910 2014 48.9 46.0 -3.0 -10 to -5%

1107 1895 2014 53.0 54.9 1.9 0 to 5%

1108 1905 2014 21.9 25.5 3.6 10 to 25%

1109 * 1907 2014 30.3 42.8 12.5 25 to 50%

1110 1909 2014 42.0 40.6 -1.3 -5 to 0%

1111 * 1892 2014 47.8 66.2 18.3 25 to 50%

1112 1908 2014 34.4 36.3 1.9 5 to 10%

1113 1901 2014 43.7 49.3 5.5 10 to 25%

1114 * 1903 2014 50.0 68.7 18.7 25 to 50%

 
MRG&P Report No. 34 181

Table E-12. Change in maximum 7-day fall rainfall by HUC-4. 

HUC4 p < 0.05 

Year Rainfall [mm] Change in Rainfall 

Min Max Min Year Max Year [mm] %Change 

0501 1893 2014 510.5 610.8 100.3 10 to 25%

0502 1896 2014 520.3 572.4 52.1 10 to 25%

0503 1896 2014 486.7 529.2 42.5 5 to 10%

0504 1900 2014 483.1 532.0 48.8 10 to 25%

0505 1902 2014 525.0 623.9 98.9 10 to 25%

0506 1899 2014 471.0 520.4 49.4 10 to 25%

0507 1911 2014 553.2 562.4 9.2 0 to 5%

0508 1900 2014 540.8 560.2 19.4 0 to 5%

0509 * 1899 2014 464.3 617.5 153.1 25 to 50%

0510 * 1898 2014 528.5 661.5 132.9 25 to 50%

0511 * 1897 2014 492.6 823.2 330.6 50 to 100%

0512 1895 2014 636.4 633.4 -3.0 -5 to 0%

0513 1896 2014 631.8 737.2 105.4 10 to 25%

0514 1895 2014 621.5 736.9 115.4 10 to 25%

0601 * 1898 2014 526.2 714.9 188.7 25 to 50%

0602 * 1896 2014 552.8 876.3 323.5 50 to 100%

0603 * 1898 2014 618.2 888.9 270.7 25 to 50%

0604 * 1901 2014 609.1 864.7 255.5 25 to 50%

0701 1893 2014 468.8 533.1 64.3 10 to 25%

0702 1896 2014 428.3 491.4 63.0 10 to 25%

0703 1907 2014 504.7 547.9 43.2 5 to 10%

0704 1896 2014 513.2 561.1 47.9 5 to 10%

0705 1905 2014 502.2 576.5 74.3 10 to 25%

0706 1904 2014 608.2 586.7 -21.5 -5 to 0%

0707 1905 2014 550.9 560.3 9.4 0 to 5%

0708 1895 2014 586.1 584.0 -2.2 -5 to 0%

0709 1896 2014 618.8 582.1 -36.7 -10 to -5%

0710 * 1899 2014 626.4 496.1 -130.3 -25 to -10%

0711 1896 2014 624.3 669.6 45.2 5 to 10%
MRG&P Report No. 34 182

HUC4 p < 0.05 

Year Rainfall [mm] Change in Rainfall 

Min Max Min Year Max Year [mm] %Change 

0712 1900 2014 526.7 601.9 75.3 10 to 25%

0713 1896 2014 604.7 594.2 -10.5 -5 to 0%

0714 1896 2014 686.3 660.5 -25.8 -5 to 0%

0801 * 1906 2014 698.1 882.7 184.6 25 to 50%

0802 1903 2014 772.3 834.2 61.9 5 to 10%

0803 * 1901 2014 682.0 934.6 252.6 25 to 50%

0804 * 1901 2014 706.4 1106.8 400.4 50 to 100%

0805 * 1911 2014 663.2 1007.4 344.2 50 to 100%

0806 * 1897 2014 549.9 1047.7 497.8 50 to 100%

0807 * 1898 2014 695.0 1142.2 447.2 50 to 100%

0808 * 1894 2014 725.5 1206.7 481.3 50 to 100%

0809 1900 2014 1045.6 998.2 -47.4 -5 to 0%

1002 * 1907 2014 270.2 204.5 -65.7 -25 to -10%

1003 1899 2014 221.5 200.2 -21.3 -10 to -5%

1004 1906 2014 226.6 216.5 -10.2 -5 to 0%

1005 1912 2014 196.6 186.8 -9.8 -5 to 0%

1006 1911 2014 221.2 214.7 -6.4 -5 to 0%

1007 1908 2014 295.3 272.3 -23.1 -10 to -5%

1008 1913 2014 204.5 219.6 15.1 5 to 10%

1009 1912 2014 247.1 253.7 6.7 0 to 5%

1010 1909 2014 203.0 257.9 54.9 25 to 50%

1011 1911 2014 220.8 288.3 67.5 25 to 50%

1012 1911 2014 255.9 277.4 21.5 5 to 10%

1013 1901 2014 231.4 303.9 72.4 25 to 50%

1014 * 1904 2014 247.7 365.8 118.1 25 to 50%

1015 1910 2014 263.4 344.2 80.8 25 to 50%

1016 1896 2014 325.8 394.9 69.1 10 to 25%

1017 1899 2014 404.1 503.9 99.8 10 to 25%

1018 1900 2014 243.3 225.1 -18.3 -10 to -5%

1019 1898 2014 251.7 280.1 28.4 10 to 25%
MRG&P Report No. 34 183

HUC4 p < 0.05 

Year Rainfall [mm] Change in Rainfall 

Min Max Min Year Max Year [mm] %Change 

1020 1902 2014 513.9 447.5 -66.5 -25 to -10%

1021 1897 2014 433.4 410.6 -22.8 -10 to -5%

1022 1899 2014 463.3 495.1 31.8 5 to 10%

1023 1897 2014 518.7 481.8 -36.9 -10 to -5%

1024 1896 2014 675.2 579.0 -96.2 -25 to -10%

1025 1893 2014 425.9 341.6 -84.3 -25 to -10%

1026 1900 2014 445.2 432.0 -13.2 -5 to 0%

1027 1894 2014 569.1 575.0 5.9 0 to 5%

1028 1894 2014 665.8 738.5 72.7 10 to 25%

1029 1897 2014 755.2 789.9 34.6 0 to 5%

1030 1895 2014 705.7 744.4 38.7 5 to 10%

1101 1897 2014 706.7 893.1 186.4 25 to 50%

1102 1897 2014 271.4 230.8 -40.6 -25 to -10%

1103 1901 2014 518.8 520.4 1.6 0 to 5%

1104 1903 2014 417.3 345.1 -72.2 -25 to -10%

1105 1900 2014 635.0 661.3 26.3 0 to 5%

1106 1910 2014 700.0 669.5 -30.5 -5 to 0%

1107 1895 2014 774.1 816.4 42.3 5 to 10%

1108 1905 2014 325.3 347.8 22.5 5 to 10%

1109 * 1907 2014 422.0 585.5 163.5 25 to 50%

1110 1909 2014 606.3 547.6 -58.7 -10 to -5%

1111 * 1892 2014 672.3 1049.7 377.4 50 to 100%

1112 1908 2014 504.7 519.1 14.4 0 to 5%

1113 1901 2014 631.8 716.6 84.8 10 to 25%

1114 * 1903 2014 722.8 988.4 265.6 25 to 50%

Additional data on rainfall trends by HUC-4 can be found in 

PRCP_byHUC4_formatted.xlsx.
MRG&P Report No. 34 184

Appendix F: Water Yield Trends by HUC-4

Table F-1. Change in annual water yield by HUC-4. 

c p < 0.05 

Year Water Yield [m3/s/km2] Change in Water Yield 

Min Max Min Year Max Year [m3/s/km2] %Change 

0501 1909 2014 6.63 7.32 0.69 10 to 25%

0502 1908 2014 7.76 7.53 -0.23 -5 to 0%

0503 1913 2014 4.46 4.88 0.42 5 to 10%

0504 * 1922 2014 3.69 4.67 0.99 25 to 50%

0505 1896 2014 5.87 5.88 0.01 0 to 5%

0506 * 1922 2014 3.17 4.28 1.11 25 to 50%

0507 1916 2014 4.40 5.03 0.63 10 to 25%

0508 1915 2014 3.49 4.37 0.88 25 to 50%

0509 * 1916 2014 4.01 4.99 0.97 10 to 25%

0510 1916 2014 5.08 5.72 0.64 10 to 25%

0511 1928 2014 6.29 7.49 1.20 10 to 25%

0512 * 1910 2014 3.11 4.73 1.62 50 to 100%

0513 1915 2015 6.86 6.54 -0.32 -5 to 0%

0514 * 1929 2014 4.61 6.00 1.39 25 to 50%

0601 1900 2015 7.62 7.42 -0.20 -5 to 0%

0602 * 1899 2014 9.33 7.54 -1.79 -25 to -10%

0603 1905 2014 6.58 7.13 0.55 5 to 10%

0604 1921 2014 6.22 6.62 0.40 5 to 10%

0701 * 1907 2014 1.00 2.06 1.06 > 100%

0702 * 1912 2014 0.00 1.35 1.35 > 100%

0703 * 1914 2014 2.61 3.22 0.61 10 to 25%

0704 * 1912 2014 1.67 2.87 1.19 50 to 100%

0705 1914 2014 3.44 3.35 -0.09 -5 to 0%

0706 * 1920 2014 1.94 3.28 1.34 50 to 100%

0707 1913 2013 3.60 3.06 -0.54 -25 to -10%

0708 * 1903 2014 1.60 3.12 1.52 50 to 100%

0709 * 1915 2014 2.23 2.99 0.76 25 to 50%
MRG&P Report No. 34 185

c p < 0.05 

Year Water Yield [m3/s/km2] Change in Water Yield 

Min Max Min Year Max Year [m3/s/km2] %Change 

0710 * 1916 2014 0.97 2.61 1.65 > 100%

0711 1923 2014 2.32 3.15 0.83 25 to 50%

0712 * 1916 2015 2.47 4.40 1.94 50 to 100%

0713 * 1909 2014 2.18 3.38 1.20 50 to 100%

0714 1909 2014 2.77 3.56 0.80 25 to 50%

0801 1930 2015 5.32 6.15 0.83 10 to 25%

0802 1927 2015 4.15 5.36 1.22 25 to 50%

0803 1909 2015 4.91 6.02 1.11 10 to 25%

0804 1929 2015 5.18 5.31 0.14 0 to 5%

0805 * 1939 2012 5.06 1.88 -3.19 -100 to -50%

0806 1939 2015 5.49 5.63 0.13 0 to 5%

0807 1941 2015 6.39 6.28 -0.12 -5 to 0%

0808 1923 2015 6.58 5.46 -1.12 -25 to -10%

0809

1002 * 1895 2014 1.44 2.15 0.72 25 to 50%

1003 * 1903 2015 1.65 1.11 -0.54 -50 to -25%

1004 * 1908 2013 0.89 0.15 -0.74 -100 to -50%

1005 1904 2013 0.16 0.17 0.00 0 to 5%

1006 1910 2015 0.31 0.27 -0.04 -25 to -10%

1007 1908 2014 3.88 3.81 -0.07 -5 to 0%

1008 1907 2015 1.87 1.62 -0.25 -25 to -10%

1009 * 1920 2013 1.59 0.55 -1.04 -100 to -50%

1010 1939 2013 0.65 0.38 -0.27 -50 to -25%

1011 * 1905 2012 0.37 0.15 -0.22 -100 to -50%

1012 * 1930 2014 0.06 0.42 0.36 > 100%

1013 1909 2014 0.25 0.24 -0.01 -10 to -5%

1014 1932 2013 0.20 0.27 0.07 25 to 50%

1015 * 1939 2013 0.30 0.54 0.24 50 to 100%

1016 * 1944 2013 0.02 0.29 0.27 > 100%

1017 * 1946 2013 0.30 0.77 0.47 > 100%
MRG&P Report No. 34 186

c p < 0.05 

Year Water Yield [m3/s/km2] Change in Water Yield 

Min Max Min Year Max Year [m3/s/km2] %Change 

1018 1905 2015 0.77 0.63 -0.13 -25 to -10%

1019 * 1896 2015 1.38 0.38 -1.01 -100 to -50%

1020 * 1938 2015 0.08 0.69 0.61 > 100%

1021 1937 2013 2.49 2.80 0.31 10 to 25%

1022 1946 2013 0.77 1.14 0.37 25 to 50%

1023 * 1929 2015 0.56 1.76 1.20 > 100%

1024 * 1923 2015 0.99 2.46 1.47 > 100%

1025 * 1929 2015 0.23 0.04 -0.20 -100 to -50%

1026 * 1919 2015 0.21 0.08 -0.14 -100 to -50%

1027 * 1918 2015 0.41 1.06 0.66 > 100%

1028 * 1922 2015 1.91 3.03 1.12 50 to 100%

1029 1919 2014 2.72 3.25 0.53 10 to 25%

1030 * 1926 2014 0.38 4.12 3.74 > 100%

1101 1922 2015 3.95 4.81 0.86 10 to 25%

1102 1897 2015 0.63 0.35 -0.27 -50 to -25%

1103 1903 2015 0.12 0.17 0.06 25 to 50%

1104 * 1943 2015 0.09 0.00 -0.09 -100 to -50%

1105 1935 2015 0.39 0.40 0.01 0 to 5%

1106 * 1937 2015 0.47 0.85 0.38 50 to 100%

1107 * 1922 2015 1.80 3.07 1.27 50 to 100%

1108 1908 2015 0.21 0.17 -0.05 -25 to -10%

1109 1939 2015 0.45 0.26 -0.20 -50 to -25%

1110 * 1938 2015 0.12 0.07 -0.05 -50 to -25%

1111 * 1928 2015 2.72 5.07 2.34 50 to 100%

1112 * 1905 2015 0.35 0.14 -0.21 -100 to -50%

1113 1936 2015 0.40 0.54 0.14 25 to 50%

1114 1925 2015 3.43 3.86 0.44 10 to 25%
MRG&P Report No. 34 187

Table F-2. Change in maximum annual daily water yield by HUC-4. 

HUC4 p < 0.05 

Year Water Yield [m3/s/km2] Change in Water Yield 

Min Max Min Year Max Year [m3/s/km2] %Change 

0501 * 1909 2014 0.190 0.159 -0.031 -25 to -10%

0502 1908 2014 0.270 0.215 -0.055 -25 to -10%

0503 * 1913 2014 0.186 0.144 -0.042 -25 to -10%

0504 * 1922 2014 0.085 0.121 0.035 25 to 50%

0505 1896 2014 0.179 0.187 0.008 0 to 5%

0506 1922 2014 0.166 0.136 -0.030 -25 to -10%

0507 1916 2014 0.234 0.165 -0.069 -50 to -25%

0508 1915 2014 0.145 0.155 0.010 5 to 10%

0509 1916 2014 0.221 0.245 0.024 10 to 25%

0510 * 1916 2014 0.192 0.265 0.073 25 to 50%

0511 1928 2014 0.244 0.207 -0.037 -25 to -10%

0512 * 1910 2014 0.100 0.191 0.092 50 to 100%

0513 1915 2015 0.293 0.353 0.060 10 to 25%

0514 * 1929 2014 0.167 0.429 0.262 > 100%

0601 1900 2015 0.184 0.214 0.030 10 to 25%

0602 1899 2014 0.231 0.176 -0.055 -25 to -10%

0603 * 1905 2014 0.182 0.404 0.222 > 100%

0604 * 1921 2014 0.238 0.338 0.099 25 to 50%

0701 * 1907 2014 0.011 0.021 0.010 50 to 100%

0702 * 1912 2014 0.004 0.034 0.030 > 100%

0703 * 1914 2014 0.032 0.046 0.015 25 to 50%

0704 1912 2014 0.063 0.066 0.004 5 to 10%

0705 1914 2014 0.060 0.061 0.001 0 to 5%

0706 1920 2014 0.125 0.105 -0.020 -25 to -10%

0707 1913 2013 0.062 0.063 0.002 0 to 5%

0708 * 1903 2014 0.030 0.101 0.070 > 100%

0709 1915 2014 0.052 0.055 0.003 5 to 10%

0710 * 1916 2014 0.024 0.069 0.045 > 100%

0711 * 1923 2014 0.149 0.241 0.092 50 to 100%
MRG&P Report No. 34 188

HUC4 p < 0.05 

Year Water Yield [m3/s/km2] Change in Water Yield 

Min Max Min Year Max Year [m3/s/km2] %Change 

0712 * 1916 2015 0.029 0.153 0.124 > 100%

0713 * 1909 2014 0.070 0.129 0.059 50 to 100%

0714 * 1909 2014 0.076 0.265 0.189 > 100%

0801 1930 2015 0.200 0.237 0.037 10 to 25%

0802 * 1927 2015 0.075 0.120 0.045 50 to 100%

0803 * 1909 2015 0.130 0.327 0.197 > 100%

0804 1929 2015 0.216 0.197 -0.019 -10 to -5%

0805 1939 2012 0.085 0.065 -0.020 -25 to -10%

0806 1939 2015 0.325 0.361 0.036 10 to 25%

0807 1941 2015 0.277 0.397 0.120 25 to 50%

0808 1923 2015 0.224 0.164 -0.059 -50 to -25%

0809

1002 * 1895 2014 0.020 0.026 0.006 25 to 50%

1003 * 1903 2015 0.033 0.012 -0.021 -100 to -50%

1004 * 1908 2013 0.016 0.004 -0.012 -100 to -50%

1005 1904 2013 0.009 0.007 -0.002 -25 to -10%

1006 * 1910 2015 0.006 0.002 -0.003 -100 to -50%

1007 1908 2014 0.072 0.060 -0.012 -25 to -10%

1008 * 1907 2015 0.043 0.025 -0.018 -50 to -25%

1009 * 1920 2013 0.038 0.010 -0.028 -100 to -50%

1010 1939 2013 0.010 0.007 -0.003 -50 to -25%

1011 1905 2012 0.020 0.012 -0.008 -50 to -25%

1012 1930 2014 0.007 0.008 0.002 25 to 50%

1013 1909 2014 0.023 0.015 -0.008 -50 to -25%

1014 1932 2013 0.008 0.009 0.001 10 to 25%

1015 * 1939 2013 0.005 0.008 0.004 50 to 100%

1016 * 1944 2013 0.002 0.008 0.006 > 100%

1017 * 1946 2013 0.014 0.029 0.015 > 100%

1018 * 1905 2015 0.020 0.009 -0.010 -100 to -50%

1019 * 1896 2015 0.024 0.012 -0.012 -100 to -50%
MRG&P Report No. 34 189

HUC4 p < 0.05 

Year Water Yield [m3/s/km2] Change in Water Yield 

Min Max Min Year Max Year [m3/s/km2] %Change 

1020 * 1938 2015 0.000 0.040 0.040 > 100%

1021 1937 2013 0.035 0.039 0.004 10 to 25%

1022 1946 2013 0.027 0.030 0.003 10 to 25%

1023 1929 2015 0.043 0.051 0.008 10 to 25%

1024 1923 2015 0.084 0.116 0.033 25 to 50%

1025 * 1929 2015 0.008 0.001 -0.007 -100 to -50%

1026 * 1919 2015 0.013 0.003 -0.010 -100 to -50%

1027 * 1918 2015 0.016 0.064 0.047 > 100%

1028 1922 2015 0.115 0.149 0.035 25 to 50%

1029 1919 2014 0.134 0.178 0.044 25 to 50%

1030 * 1926 2014 0.017 0.335 0.318 > 100%

1101 1922 2015 0.143 0.204 0.061 25 to 50%

1102 * 1897 2015 0.017 0.009 -0.008 -50 to -25%

1103 * 1903 2015 0.006 0.010 0.004 50 to 100%

1104 * 1943 2015 0.012 -0.001 -0.013 > -100%

1105 1935 2015 0.036 0.025 -0.011 -50 to -25%

1106 1937 2015 0.041 0.045 0.004 10 to 25%

1107 * 1922 2015 0.095 0.149 0.054 50 to 100%

1108 * 1908 2015 0.012 0.005 -0.008 -100 to -50%

1109 * 1939 2015 0.030 0.006 -0.024 -100 to -50%

1110 * 1938 2015 0.011 0.002 -0.009 -100 to -50%

1111 * 1928 2015 0.097 0.331 0.234 > 100%

1112 * 1905 2015 0.052 0.009 -0.043 -100 to -50%

1113 1936 2015 0.039 0.025 -0.014 -50 to -25%

1114 1925 2015 0.159 0.169 0.010 5 to 10%

 
MRG&P Report No. 34 190

Table F-3. Change in maximum annual 7-day water yield totals by HUC-4. 

HUC4 p < 0.05 

Year Water Yield [m3/s/km2] Change in Water Yield 

Min Max Min Year Max Year [m3/s/km2] %Change 

0501 1909 2014 0.681 0.592 -0.089 -25 to -10%

0502 1908 2014 0.743 0.655 -0.088 -25 to -10%

0503 * 1913 2014 0.550 0.427 -0.123 -25 to -10%

0504 1922 2014 0.380 0.404 0.023 5 to 10%

0505 1896 2014 0.528 0.542 0.014 0 to 5%

0506 1922 2014 0.503 0.474 -0.029 -10 to -5%

0507 1916 2014 0.632 0.466 -0.165 -50 to -25%

0508 1915 2014 0.449 0.491 0.042 5 to 10%

0509 1916 2014 0.570 0.622 0.052 5 to 10%

0510 1916 2014 0.710 0.632 -0.078 -25 to -10%

0511 1928 2014 0.847 0.639 -0.209 -25 to -10%

0512 * 1910 2014 0.437 0.566 0.128 25 to 50%

0513 1915 2015 0.856 0.807 -0.049 -10 to -5%

0514 * 1929 2014 0.639 0.845 0.206 25 to 50%

0601 1900 2015 0.573 0.594 0.020 0 to 5%

0602 1899 2014 0.663 0.543 -0.120 -25 to -10%

0603 1905 2014 0.738 0.899 0.161 10 to 25%

0604 1921 2014 0.753 0.851 0.097 10 to 25%

0701 * 1907 2014 0.066 0.129 0.063 50 to 100%

0702 * 1912 2014 0.015 0.163 0.148 > 100%

0703 * 1914 2014 0.186 0.247 0.061 25 to 50%

0704 1912 2014 0.192 0.231 0.040 10 to 25%

0705 1914 2014 0.284 0.260 -0.024 -10 to -5%

0706 1920 2014 0.296 0.298 0.002 0 to 5%

0707 * 1913 2013 0.297 0.230 -0.067 -25 to -10%

0708 * 1903 2014 0.152 0.340 0.188 > 100%

0709 1915 2014 0.226 0.213 -0.013 -10 to -5%

0710 * 1916 2014 0.125 0.272 0.147 > 100%

0711 1923 2014 0.413 0.570 0.157 25 to 50%
MRG&P Report No. 34 191

HUC4 p < 0.05 

Year Water Yield [m3/s/km2] Change in Water Yield 

Min Max Min Year Max Year [m3/s/km2] %Change 

0712 * 1916 2015 0.196 0.465 0.270 > 100%

0713 * 1909 2014 0.284 0.418 0.135 25 to 50%

0714 * 1909 2014 0.352 0.582 0.229 50 to 100%

0801 1930 2015 0.768 0.764 -0.004 -5 to 0%

0802 1927 2015 0.437 0.553 0.116 25 to 50%

0803 1909 2015 0.567 0.727 0.160 25 to 50%

0804 1929 2015 0.732 0.626 -0.105 -25 to -10%

0805 * 1939 2012 0.481 0.284 -0.197 -50 to -25%

0806 1939 2015 0.777 0.861 0.085 10 to 25%

0807 1941 2015 0.782 1.087 0.305 25 to 50%

0808 1923 2015 0.759 0.732 -0.027 -5 to 0%

0809

1002 1895 2014 0.124 0.150 0.026 10 to 25%

1003 * 1903 2015 0.166 0.064 -0.103 -100 to -50%

1004 * 1908 2013 0.084 0.018 -0.067 -100 to -50%

1005 1904 2013 0.037 0.026 -0.011 -50 to -25%

1006 * 1910 2015 0.031 0.011 -0.020 -100 to -50%

1007 1908 2014 0.412 0.364 -0.047 -25 to -10%

1008 * 1907 2015 0.228 0.132 -0.096 -50 to -25%

1009 * 1920 2013 0.187 0.052 -0.136 -100 to -50%

1010 1939 2013 0.057 0.037 -0.020 -50 to -25%

1011 1905 2012 0.078 0.043 -0.035 -50 to -25%

1012 1930 2014 0.017 0.037 0.020 > 100%

1013 1909 2014 0.079 0.048 -0.032 -50 to -25%

1014 1932 2013 0.030 0.032 0.002 5 to 10%

1015 * 1939 2013 0.020 0.037 0.017 50 to 100%

1016 * 1944 2013 0.009 0.040 0.031 > 100%

1017 * 1946 2013 0.056 0.111 0.055 50 to 100%

1018 * 1905 2015 0.100 0.051 -0.048 -50 to -25%

1019 * 1896 2015 0.137 0.042 -0.094 -100 to -50%
MRG&P Report No. 34 192

HUC4 p < 0.05 

Year Water Yield [m3/s/km2] Change in Water Yield 

Min Max Min Year Max Year [m3/s/km2] %Change 

1020 * 1938 2015 0.009 0.087 0.078 > 100%

1021 1937 2013 0.124 0.146 0.022 10 to 25%

1022 1946 2013 0.105 0.104 -0.001 -5 to 0%

1023 1929 2015 0.117 0.178 0.061 50 to 100%

1024 * 1923 2015 0.190 0.319 0.129 50 to 100%

1025 * 1929 2015 0.023 0.004 -0.019 -100 to -50%

1026 * 1919 2015 0.038 0.008 -0.030 -100 to -50%

1027 * 1918 2015 0.058 0.200 0.142 > 100%

1028 1922 2015 0.381 0.428 0.047 10 to 25%

1029 1919 2014 0.392 0.478 0.085 10 to 25%

1030 * 1926 2014 0.065 0.682 0.617 > 100%

1101 1922 2015 0.402 0.479 0.077 10 to 25%

1102 * 1897 2015 0.069 0.029 -0.041 -100 to -50%

1103 1903 2015 0.020 0.029 0.009 25 to 50%

1104 * 1943 2015 0.020 -0.001 -0.021 > -100%

1105 1935 2015 0.082 0.061 -0.021 -50 to -25%

1106 1937 2015 0.096 0.125 0.030 25 to 50%

1107 1922 2015 0.342 0.436 0.094 25 to 50%

1108 * 1908 2015 0.042 0.017 -0.025 -100 to -50%

1109 * 1939 2015 0.084 0.027 -0.056 -100 to -50%

1110 * 1938 2015 0.024 0.006 -0.017 -100 to -50%

1111 * 1928 2015 0.367 0.725 0.359 50 to 100%

1112 * 1905 2015 0.093 0.023 -0.070 -100 to -50%

1113 1936 2015 0.088 0.083 -0.005 -10 to -5%

1114 1925 2015 0.558 0.581 0.023 0 to 5%

 
MRG&P Report No. 34 193

Table F-4. Change in winter water yield by HUC-4. 

HUC4 p < 0.05 

Year Water Yield [m3/s/km2] Change in Water Yield 

Min Max Min Year Max Year [m3/s/km2] %Change 

0501 1909 2014 2.09 2.35 0.26 10 to 25%

0502 1908 2014 2.90 2.65 -0.26 -10 to -5%

0503 1913 2014 1.55 1.66 0.11 5 to 10%

0504 1922 2014 1.16 1.48 0.32 25 to 50%

0505 1896 2014 2.03 1.96 -0.07 -5 to 0%

0506 1922 2014 1.06 1.37 0.31 25 to 50%

0507 1916 2014 1.85 1.61 -0.25 -25 to -10%

0508 1915 2014 1.03 1.37 0.33 25 to 50%

0509 1916 2014 1.48 1.73 0.26 10 to 25%

0510 1916 2014 2.09 2.10 0.01 0 to 5%

0511 1928 2014 2.38 2.89 0.51 10 to 25%

0512 1910 2014 0.94 1.44 0.50 50 to 100%

0513 1915 2015 2.97 2.52 -0.45 -25 to -10%

0514 1929 2014 1.69 2.12 0.43 25 to 50%

0601 1900 2015 2.36 2.53 0.16 5 to 10%

0602 1899 2014 2.78 2.55 -0.23 -10 to -5%

0603 1905 2014 2.50 3.07 0.56 10 to 25%

0604 1921 2014 2.44 2.63 0.19 5 to 10%

0701 * 1907 2014 0.11 0.27 0.16 > 100%

0702 * 1912 2014 -0.01 0.08 0.09 > 100%

0703 1914 2014 0.37 0.42 0.04 10 to 25%

0704 * 1912 2014 0.22 0.35 0.12 50 to 100%

0705 1914 2014 0.47 0.56 0.08 10 to 25%

0706 1920 2014 0.36 0.48 0.12 25 to 50%

0707 1913 2013 0.50 0.54 0.04 5 to 10%

0708 1903 2014 0.24 0.35 0.11 25 to 50%

0709 1915 2014 0.49 0.62 0.13 25 to 50%

0710 1916 2014 0.10 0.21 0.10 50 to 100%

0711 1923 2014 0.44 0.62 0.18 25 to 50%
MRG&P Report No. 34 194

HUC4 p < 0.05 

Year Water Yield [m3/s/km2] Change in Water Yield 

Min Max Min Year Max Year [m3/s/km2] %Change 

0712 * 1916 2015 0.65 1.03 0.39 50 to 100%

0713 1909 2014 0.53 0.79 0.26 50 to 100%

0714 1909 2014 0.62 1.01 0.39 50 to 100%

0801 1930 2015 2.19 2.01 -0.18 -10 to -5%

0802 1927 2015 1.30 1.75 0.45 25 to 50%

0803 1909 2015 1.57 2.32 0.75 25 to 50%

0804 1929 2015 2.04 1.86 -0.18 -10 to -5%

0805 * 1939 2012 1.74 0.77 -0.96 -100 to -50%

0806 1939 2015 1.90 2.33 0.43 10 to 25%

0807 1941 2015 2.30 2.26 -0.04 -5 to 0%

0808 1923 2015 2.36 2.37 0.01 0 to 5%

0809 *

1002 * 1895 2014 0.16 0.26 0.10 50 to 100%

1003 1903 2015 0.15 0.16 0.01 0 to 5%

1004 * 1908 2013 0.06 0.02 -0.04 -100 to -50%

1005 * 1904 2013 0.00 0.01 0.00 > 100%

1006 * 1910 2015 0.01 0.06 0.05 > 100%

1007 1908 2014 0.24 0.26 0.01 0 to 5%

1008 1907 2015 0.12 0.14 0.02 10 to 25%

1009 * 1920 2013 0.11 0.06 -0.05 -50 to -25%

1010 1939 2013 0.07 0.06 -0.01 -25 to -10%

1011 1905 2012 0.01 0.01 0.00 10 to 25%

1012 * 1930 2014 -0.01 0.05 0.06 > 100%

1013 * 1909 2014 0.00 0.01 0.01 > 100%

1014 * 1932 2013 0.01 0.03 0.02 > 100%

1015 * 1939 2013 0.05 0.12 0.07 > 100%

1016 * 1944 2013 0.00 0.01 0.01 > 100%

1017 * 1946 2013 0.01 0.04 0.03 > 100%

1018 * 1905 2015 0.04 0.05 0.01 25 to 50%

1019 1896 2015 0.06 0.06 0.00 -5 to 0%
MRG&P Report No. 34 195

HUC4 p < 0.05 

Year Water Yield [m3/s/km2] Change in Water Yield 

Min Max Min Year Max Year [m3/s/km2] %Change 

1020 * 1938 2015 0.01 0.11 0.10 > 100%

1021 1937 2013 0.61 0.68 0.08 10 to 25%

1022 * 1946 2013 0.09 0.19 0.10 > 100%

1023 * 1929 2015 0.04 0.20 0.16 > 100%

1024 * 1923 2015 0.13 0.26 0.13 50 to 100%

1025 * 1929 2015 0.03 0.01 -0.03 -100 to -50%

1026 1919 2015 0.01 0.01 0.00 -25 to -10%

1027 * 1918 2015 0.04 0.10 0.06 > 100%

1028 1922 2015 0.28 0.38 0.09 25 to 50%

1029 1919 2014 0.54 0.62 0.08 10 to 25%

1030 * 1926 2014 0.05 0.58 0.53 > 100%

1101 1922 2015 1.05 1.24 0.19 10 to 25%

1102 * 1897 2015 0.06 0.03 -0.03 -100 to -50%

1103 * 1903 2015 0.01 0.02 0.01 50 to 100%

1104 * 1943 2015 0.01 0.00 -0.01 > -100%

1105 * 1935 2015 0.02 0.05 0.03 > 100%

1106 * 1937 2015 0.03 0.11 0.08 > 100%

1107 * 1922 2015 0.18 0.45 0.27 > 100%

1108 * 1908 2015 0.02 0.01 -0.01 -100 to -50%

1109 1939 2015 0.04 0.03 -0.01 -25 to -10%

1110 1938 2015 0.01 0.01 0.00 25 to 50%

1111 * 1928 2015 0.78 1.28 0.51 50 to 100%

1112 * 1905 2015 0.01 0.03 0.02 > 100%

1113 1936 2015 0.03 0.05 0.02 50 to 100%

1114 1925 2015 1.12 1.29 0.16 10 to 25%

 
MRG&P Report No. 34 196

Table F-5. Change in spring water yield by HUC-4. 

HUC4 p < 0.05 

Year Water Yield [m3/s/km2] Change in Water Yield 

Min Max Min Year Max Year [m3/s/km2] %Change 

0501 1909 2014 3.04 2.64 -0.40 -25 to -10%

0502 1908 2014 2.90 2.93 0.03 0 to 5%

0503 1913 2014 1.93 1.83 -0.10 -10 to -5%

0504 1922 2014 1.56 1.76 0.21 10 to 25%

0505 1896 2014 2.14 2.38 0.24 10 to 25%

0506 1922 2014 1.32 1.66 0.34 25 to 50%

0507 1916 2014 1.94 2.12 0.17 5 to 10%

0508 1915 2014 1.35 1.67 0.32 10 to 25%

0509 1916 2014 1.63 2.08 0.45 25 to 50%

0510 1916 2014 2.12 2.26 0.14 5 to 10%

0511 1928 2014 2.59 2.56 -0.03 -5 to 0%

0512 * 1910 2014 1.25 1.84 0.59 25 to 50%

0513 1915 2015 2.59 2.43 -0.16 -10 to -5%

0514 1929 2014 2.07 2.20 0.13 5 to 10%

0601 1900 2015 2.60 2.59 -0.02 -5 to 0%

0602 * 1899 2014 3.26 2.17 -1.08 -50 to -25%

0603 1905 2014 2.53 2.39 -0.13 -10 to -5%

0604 1921 2014 2.37 2.22 -0.14 -10 to -5%

0701 * 1907 2014 0.35 0.80 0.45 > 100%

0702 * 1912 2014 0.06 0.68 0.62 > 100%

0703 1914 2014 1.06 1.29 0.23 10 to 25%

0704 * 1912 2014 0.74 1.04 0.30 25 to 50%

0705 1914 2014 1.29 1.21 -0.08 -10 to -5%

0706 * 1920 2014 0.77 1.17 0.40 50 to 100%

0707 * 1913 2013 1.47 1.06 -0.41 -50 to -25%

0708 * 1903 2014 0.65 1.30 0.65 > 100%

0709 1915 2014 0.90 1.10 0.21 10 to 25%

0710 * 1916 2014 0.46 1.08 0.62 > 100%

0711 * 1923 2014 0.76 1.38 0.62 50 to 100%
MRG&P Report No. 34 197

HUC4 p < 0.05 

Year Water Yield [m3/s/km2] Change in Water Yield 

Min Max Min Year Max Year [m3/s/km2] %Change 

0712 * 1916 2015 1.18 1.65 0.47 25 to 50%

0713 * 1909 2014 0.90 1.43 0.53 50 to 100%

0714 1909 2014 1.14 1.49 0.34 25 to 50%

0801 1930 2015 1.81 2.21 0.39 10 to 25%

0802 1927 2015 1.83 1.97 0.14 5 to 10%

0803 1909 2015 2.02 1.92 -0.10 -10 to -5%

0804 1929 2015 2.20 1.96 -0.24 -25 to -10%

0805 * 1939 2012 2.09 0.39 -1.70 -100 to -50%

0806 1939 2015 2.12 1.92 -0.20 -10 to -5%

0807 1941 2015 2.31 1.75 -0.56 -25 to -10%

0808 1923 2015 2.28 1.51 -0.78 -50 to -25%

0809

1002 * 1895 2014 0.50 0.68 0.18 25 to 50%

1003 * 1903 2015 0.62 0.28 -0.35 -100 to -50%

1004 * 1908 2013 0.34 0.05 -0.29 -100 to -50%

1005 1904 2013 0.09 0.06 -0.03 -50 to -25%

1006 1910 2015 0.11 0.08 -0.03 -50 to -25%

1007 1908 2014 0.84 0.79 -0.04 -10 to -5%

1008 1907 2015 0.39 0.38 -0.01 -5 to 0%

1009 * 1920 2013 0.53 0.16 -0.37 -100 to -50%

1010 1939 2013 0.19 0.13 -0.06 -50 to -25%

1011 1905 2012 0.15 0.13 -0.03 -25 to -10%

1012 * 1930 2014 0.03 0.15 0.12 > 100%

1013 1909 2014 0.15 0.14 0.00 -5 to 0%

1014 1932 2013 0.09 0.14 0.05 50 to 100%

1015 * 1939 2013 0.13 0.20 0.07 50 to 100%

1016 * 1944 2013 0.03 0.12 0.09 > 100%

1017 * 1946 2013 0.17 0.43 0.27 > 100%

1018 1905 2015 0.29 0.23 -0.07 -25 to -10%

1019 * 1896 2015 0.34 0.13 -0.21 -100 to -50%
MRG&P Report No. 34 198

HUC4 p < 0.05 

Year Water Yield [m3/s/km2] Change in Water Yield 

Min Max Min Year Max Year [m3/s/km2] %Change 

1020 * 1938 2015 0.01 0.26 0.24 > 100%

1021 1937 2013 0.77 0.86 0.10 10 to 25%

1022 1946 2013 0.29 0.44 0.16 50 to 100%

1023 * 1929 2015 0.25 0.60 0.36 > 100%

1024 * 1923 2015 0.29 0.91 0.62 > 100%

1025 * 1929 2015 0.07 0.01 -0.06 -100 to -50%

1026 * 1919 2015 0.04 0.02 -0.02 -50 to -25%

1027 * 1918 2015 0.11 0.34 0.23 > 100%

1028 * 1922 2015 0.62 1.32 0.70 > 100%

1029 1919 2014 1.11 1.29 0.19 10 to 25%

1030 * 1926 2014 0.09 1.52 1.43 > 100%

1101 1922 2015 1.64 1.86 0.22 10 to 25%

1102 1897 2015 0.14 0.11 -0.03 -25 to -10%

1103 * 1903 2015 0.02 0.05 0.03 > 100%

1104 * 1943 2015 0.02 0.00 -0.02 -100 to -50%

1105 1935 2015 0.13 0.15 0.02 10 to 25%

1106 1937 2015 0.17 0.31 0.14 50 to 100%

1107 * 1922 2015 0.66 1.25 0.60 50 to 100%

1108 1908 2015 0.07 0.04 -0.03 -50 to -25%

1109 * 1939 2015 0.18 0.07 -0.11 -100 to -50%

1110 1938 2015 0.03 0.03 -0.01 -50 to -25%

1111 * 1928 2015 1.20 1.94 0.74 50 to 100%

1112 1905 2015 0.11 0.05 -0.05 -50 to -25%

1113 1936 2015 0.15 0.15 0.00 0 to 5%

1114 1925 2015 1.64 1.40 -0.25 -25 to -10%

 
MRG&P Report No. 34 199

Table F-6. Change in summer water yield by HUC-4. 

HUC4 p < 0.05 

Year Water Yield [m3/s/km2] Change in Water Yield 

Min Max Min Year Max Year [m3/s/km2] %Change 

0501 * 1909 2014 0.54 0.96 0.42 50 to 100%

0502 1908 2014 1.00 0.93 -0.06 -10 to -5%

0503 * 1913 2014 0.38 0.72 0.33 50 to 100%

0504 * 1922 2014 0.45 0.74 0.29 50 to 100%

0505 1896 2014 0.92 0.79 -0.12 -25 to -10%

0506 * 1922 2014 0.31 0.69 0.38 > 100%

0507 * 1916 2014 0.32 0.67 0.35 > 100%

0508 1915 2014 0.47 0.76 0.29 50 to 100%

0509 1916 2014 0.44 0.60 0.16 25 to 50%

0510 1916 2014 0.51 0.58 0.08 10 to 25%

0511 1928 2014 0.63 0.79 0.17 25 to 50%

0512 * 1910 2014 0.36 0.76 0.39 > 100%

0513 1915 2015 0.65 0.64 -0.02 -5 to 0%

0514 1929 2014 0.43 0.64 0.21 25 to 50%

0601 * 1900 2015 1.48 1.12 -0.35 -25 to -10%

0602 * 1899 2014 1.86 1.28 -0.58 -50 to -25%

0603 1905 2014 0.77 0.54 -0.23 -50 to -25%

0604 1921 2014 0.66 0.67 0.01 0 to 5%

0701 * 1907 2014 0.28 0.53 0.25 50 to 100%

0702 * 1912 2014 -0.03 0.39 0.43 > 100%

0703 1914 2014 0.61 0.76 0.15 25 to 50%

0704 * 1912 2014 0.35 0.75 0.40 > 100%

0705 1914 2014 0.79 0.72 -0.08 -10 to -5%

0706 * 1920 2014 0.41 0.86 0.44 > 100%

0707 * 1913 2013 0.83 0.63 -0.21 -25 to -10%

0708 * 1903 2014 0.37 0.89 0.52 > 100%

0709 * 1915 2014 0.36 0.72 0.36 50 to 100%

0710 * 1916 2014 0.25 0.89 0.65 > 100%

0711 1923 2014 0.55 0.54 -0.01 -5 to 0%
MRG&P Report No. 34 200

HUC4 p < 0.05 

Year Water Yield [m3/s/km2] Change in Water Yield 

Min Max Min Year Max Year [m3/s/km2] %Change 

0712 * 1916 2015 0.28 0.96 0.68 > 100%

0713 * 1909 2014 0.40 0.65 0.25 50 to 100%

0714 1909 2014 0.42 0.50 0.08 10 to 25%

0801 1930 2015 0.56 0.74 0.18 25 to 50%

0802 1927 2015 0.49 0.55 0.05 10 to 25%

0803 1909 2015 0.56 0.56 0.00 -5 to 0%

0804 1929 2015 0.36 0.49 0.13 25 to 50%

0805 1939 2012 0.36 0.31 -0.05 -25 to -10%

0806 1939 2015 0.58 0.45 -0.13 -25 to -10%

0807 1941 2015 0.81 0.69 -0.12 -25 to -10%

0808 1923 2015 0.75 0.50 -0.25 -50 to -25%

0809

1002 * 1895 2014 0.53 0.81 0.28 50 to 100%

1003 * 1903 2015 0.67 0.35 -0.32 -50 to -25%

1004 * 1908 2013 0.31 0.08 -0.22 -100 to -50%

1005 1904 2013 0.03 0.05 0.02 50 to 100%

1006 1910 2015 0.06 0.07 0.02 25 to 50%

1007 1908 2014 2.25 2.09 -0.16 -10 to -5%

1008 * 1907 2015 1.12 0.65 -0.47 -50 to -25%

1009 * 1920 2013 0.68 0.23 -0.45 -100 to -50%

1010 1939 2013 0.28 0.14 -0.14 -50 to -25%

1011 * 1905 2012 0.13 0.00 -0.13 -100 to -50%

1012 * 1930 2014 0.03 0.12 0.10 > 100%

1013 1909 2014 0.06 0.04 -0.02 -50 to -25%

1014 1932 2013 0.06 0.06 0.00 5 to 10%

1015 * 1939 2013 0.06 0.12 0.06 50 to 100%

1016 * 1944 2013 -0.01 0.09 0.10 > 100%

1017 * 1946 2013 0.07 0.19 0.12 > 100%

1018 1905 2015 0.34 0.20 -0.14 -50 to -25%

1019 * 1896 2015 0.76 0.07 -0.69 -100 to -50%
MRG&P Report No. 34 201

HUC4 p < 0.05 

Year Water Yield [m3/s/km2] Change in Water Yield 

Min Max Min Year Max Year [m3/s/km2] %Change 

1020 * 1938 2015 0.02 0.20 0.18 > 100%

1021 1937 2013 0.53 0.58 0.05 5 to 10%

1022 1946 2013 0.21 0.29 0.07 25 to 50%

1023 * 1929 2015 0.19 0.50 0.31 > 100%

1024 * 1923 2015 0.32 0.67 0.35 > 100%

1025 * 1929 2015 0.08 0.01 -0.07 -100 to -50%

1026 * 1919 2015 0.09 0.02 -0.07 -100 to -50%

1027 * 1918 2015 0.15 0.34 0.19 > 100%

1028 1922 2015 0.52 0.75 0.23 25 to 50%

1029 1919 2014 0.54 0.58 0.04 5 to 10%

1030 * 1926 2014 0.14 0.81 0.67 > 100%

1101 1922 2015 0.65 0.61 -0.04 -10 to -5%

1102 * 1897 2015 0.31 0.09 -0.22 -100 to -50%

1103 1903 2015 0.04 0.05 0.01 10 to 25%

1104 * 1943 2015 0.04 0.00 -0.04 > -100%

1105 1935 2015 0.10 0.09 -0.01 -10 to -5%

1106 1937 2015 0.13 0.22 0.09 50 to 100%

1107 1922 2015 0.46 0.69 0.23 25 to 50%

1108 * 1908 2015 0.09 0.05 -0.04 -50 to -25%

1109 * 1939 2015 0.11 0.05 -0.06 -100 to -50%

1110 * 1938 2015 0.04 0.02 -0.02 -100 to -50%

1111 1928 2015 0.26 0.46 0.20 50 to 100%

1112 * 1905 2015 0.12 0.02 -0.10 -100 to -50%

1113 1936 2015 0.12 0.09 -0.03 -50 to -25%

1114 1925 2015 0.32 0.36 0.04 10 to 25%

 
MRG&P Report No. 34 202

Table F-7. Change in fall water yield by HUC-4. 

HUC4 p < 0.05 

Year Water Yield [m3/s/km2] Change in Water Yield 

Min Max Min Year Max Year [m3/s/km2] %Change 

0501 * 1909 2014 0.75 1.17 0.41 50 to 100%

0502 1908 2014 0.81 0.99 0.18 10 to 25%

0503 * 1913 2014 0.37 0.60 0.23 50 to 100%

0504 * 1922 2014 0.25 0.51 0.26 > 100%

0505 1896 2014 0.67 0.79 0.12 10 to 25%

0506 * 1922 2014 0.10 0.41 0.31 > 100%

0507 * 1916 2014 0.15 0.54 0.39 > 100%

0508 1915 2014 0.30 0.41 0.11 25 to 50%

0509 * 1916 2014 0.16 0.52 0.37 > 100%

0510 * 1916 2014 0.18 0.60 0.42 > 100%

0511 * 1928 2014 0.32 1.06 0.74 > 100%

0512 1910 2014 0.26 0.42 0.15 50 to 100%

0513 1915 2015 0.46 0.73 0.27 50 to 100%

0514 * 1929 2014 0.23 0.63 0.40 > 100%

0601 1900 2015 1.01 1.12 0.11 10 to 25%

0602 1899 2014 1.15 1.29 0.14 10 to 25%

0603 1905 2014 0.51 0.76 0.25 25 to 50%

0604 1921 2014 0.52 0.78 0.26 25 to 50%

0701 * 1907 2014 0.22 0.36 0.14 50 to 100%

0702 * 1912 2014 -0.01 0.11 0.12 > 100%

0703 1914 2014 0.49 0.63 0.14 25 to 50%

0704 * 1912 2014 0.25 0.51 0.25 50 to 100%

0705 1914 2014 0.64 0.71 0.07 10 to 25%

0706 * 1920 2014 0.29 0.51 0.22 50 to 100%

0707 1913 2013 0.68 0.62 -0.07 -10 to -5%

0708 1903 2014 0.28 0.32 0.04 10 to 25%

0709 1915 2014 0.36 0.52 0.16 25 to 50%

0710 1916 2014 0.14 0.26 0.12 50 to 100%

0711 1923 2014 0.32 0.36 0.03 10 to 25%
MRG&P Report No. 34 203

HUC4 p < 0.05 

Year Water Yield [m3/s/km2] Change in Water Yield 

Min Max Min Year Max Year [m3/s/km2] %Change 

0712 * 1916 2015 0.29 0.68 0.39 > 100%

0713 1909 2014 0.20 0.24 0.03 10 to 25%

0714 1909 2014 0.25 0.33 0.08 25 to 50%

0801 * 1930 2015 0.42 0.74 0.32 50 to 100%

0802 * 1927 2015 0.30 0.58 0.28 50 to 100%

0803 * 1909 2015 0.27 0.73 0.45 > 100%

0804 1929 2015 0.34 0.49 0.15 25 to 50%

0805 1939 2012 0.23 0.30 0.07 25 to 50%

0806 1939 2015 0.39 0.52 0.13 25 to 50%

0807 1941 2015 0.68 0.85 0.17 25 to 50%

0808 1923 2015 0.59 0.78 0.19 25 to 50%

0809 *

1002 * 1895 2014 0.24 0.31 0.07 25 to 50%

1003 1903 2015 0.21 0.19 -0.02 -10 to -5%

1004 * 1908 2013 0.08 0.02 -0.06 -100 to -50%

1005 * 1904 2013 0.01 0.01 0.01 > 100%

1006 1910 2015 0.05 0.05 -0.01 -25 to -10%

1007 1908 2014 0.46 0.39 -0.07 -25 to -10%

1008 1907 2015 0.23 0.22 -0.01 -10 to -5%

1009 * 1920 2013 0.15 0.09 -0.06 -50 to -25%

1010 1939 2013 0.10 0.05 -0.05 -50 to -25%

1011 * 1905 2012 0.01 0.00 -0.01 -100 to -50%

1012 * 1930 2014 -0.01 0.06 0.07 > 100%

1013 * 1909 2014 0.01 0.01 0.01 > 100%

1014 1932 2013 0.01 0.02 0.01 50 to 100%

1015 * 1939 2013 0.05 0.09 0.04 50 to 100%

1016 * 1944 2013 -0.01 0.03 0.04 > 100%

1017 * 1946 2013 0.01 0.08 0.06 > 100%

1018 1905 2015 0.07 0.06 -0.01 -25 to -10%

1019 * 1896 2015 0.13 0.06 -0.07 -100 to -50%
MRG&P Report No. 34 204

HUC4 p < 0.05 

Year Water Yield [m3/s/km2] Change in Water Yield 

Min Max Min Year Max Year [m3/s/km2] %Change 

1020 * 1938 2015 0.01 0.10 0.09 > 100%

1021 1937 2013 0.54 0.63 0.10 10 to 25%

1022 * 1946 2013 0.08 0.15 0.08 > 100%

1023 * 1929 2015 0.05 0.22 0.17 > 100%

1024 1923 2015 0.12 0.26 0.14 > 100%

1025 * 1929 2015 0.03 0.00 -0.03 -100 to -50%

1026 * 1919 2015 0.03 0.01 -0.02 -100 to -50%

1027 1918 2015 0.07 0.10 0.03 25 to 50%

1028 1922 2015 0.26 0.35 0.10 25 to 50%

1029 1919 2014 0.39 0.36 -0.02 -10 to -5%

1030 * 1926 2014 0.06 0.47 0.41 > 100%

1101 1922 2015 0.54 0.59 0.06 10 to 25%

1102 1897 2015 0.08 0.06 -0.03 -50 to -25%

1103 1903 2015 0.02 0.02 0.00 -5 to 0%

1104 * 1943 2015 0.01 0.00 -0.01 -100 to -50%

1105 1935 2015 0.05 0.06 0.01 10 to 25%

1106 1937 2015 0.09 0.11 0.02 10 to 25%

1107 1922 2015 0.32 0.31 -0.01 -5 to 0%

1108 1908 2015 0.03 0.03 0.00 -5 to 0%

1109 1939 2015 0.04 0.02 -0.02 -100 to -50%

1110 1938 2015 0.01 0.01 0.00 -10 to -5%

1111 * 1928 2015 0.18 0.58 0.40 > 100%

1112 1905 2015 0.04 0.02 -0.02 -100 to -50%

1113 1936 2015 0.06 0.08 0.02 25 to 50%

1114 1925 2015 0.20 0.38 0.18 50 to 100%

 
MRG&P Report No. 34 205

Table F-8. Change in maximum daily spring water yield by HUC-4. 

HUC4 p < 0.05 

Year Water Yield [m3/s/km2] Change in Water Yield 

Min Max Min Year Max Year [m3/s/km2] %Change 

0501 * 1909 2014 0.162 0.110 -0.052 -50 to -25%

0502 1908 2014 0.178 0.170 -0.008 -5 to 0%

0503 * 1913 2014 0.143 0.096 -0.047 -50 to -25%

0504 1922 2014 0.069 0.082 0.013 10 to 25%

0505 1896 2014 0.116 0.141 0.025 10 to 25%

0506 1922 2014 0.112 0.098 -0.014 -25 to -10%

0507 1916 2014 0.161 0.138 -0.023 -25 to -10%

0508 1915 2014 0.105 0.099 -0.005 -5 to 0%

0509 1916 2014 0.155 0.171 0.016 10 to 25%

0510 1916 2014 0.130 0.188 0.058 25 to 50%

0511 1928 2014 0.161 0.163 0.002 0 to 5%

0512 * 1910 2014 0.073 0.124 0.051 50 to 100%

0513 * 1915 2015 0.165 0.246 0.081 25 to 50%

0514 * 1929 2014 0.126 0.283 0.157 > 100%

0601 1900 2015 0.115 0.135 0.020 10 to 25%

0602 1899 2014 0.140 0.112 -0.027 -25 to -10%

0603 * 1905 2014 0.129 0.258 0.129 50 to 100%

0604 * 1921 2014 0.144 0.229 0.085 50 to 100%

0701 * 1907 2014 0.010 0.019 0.009 50 to 100%

0702 * 1912 2014 0.006 0.025 0.019 > 100%

0703 * 1914 2014 0.028 0.040 0.012 25 to 50%

0704 1912 2014 0.053 0.045 -0.007 -25 to -10%

0705 1914 2014 0.052 0.051 -0.001 -5 to 0%

0706 1920 2014 0.078 0.065 -0.013 -25 to -10%

0707 1913 2013 0.053 0.049 -0.004 -10 to -5%

0708 * 1903 2014 0.022 0.069 0.047 > 100%

0709 1915 2014 0.038 0.038 0.000 -5 to 0%

0710 * 1916 2014 0.017 0.048 0.031 > 100%

0711 * 1923 2014 0.090 0.155 0.065 50 to 100%
MRG&P Report No. 34 206

HUC4 p < 0.05 

Year Water Yield [m3/s/km2] Change in Water Yield 

Min Max Min Year Max Year [m3/s/km2] %Change 

0712 * 1916 2015 0.032 0.099 0.067 > 100%

0713 * 1909 2014 0.047 0.080 0.033 50 to 100%

0714 * 1909 2014 0.063 0.160 0.097 > 100%

0801 * 1930 2015 0.113 0.176 0.063 50 to 100%

0802 * 1927 2015 0.056 0.090 0.033 50 to 100%

0803 * 1909 2015 0.098 0.225 0.128 > 100%

0804 1929 2015 0.158 0.110 -0.048 -50 to -25%

0805 * 1939 2012 0.069 0.046 -0.023 -50 to -25%

0806 1939 2015 0.244 0.186 -0.058 -25 to -10%

0807 1941 2015 0.246 0.229 -0.017 -10 to -5%

0808 * 1923 2015 0.153 0.076 -0.077 -100 to -50%

0809 *

1002 1895 2014 0.015 0.020 0.004 25 to 50%

1003 * 1903 2015 0.025 0.008 -0.017 -100 to -50%

1004 * 1908 2013 0.013 0.002 -0.010 -100 to -50%

1005 1904 2013 0.008 0.005 -0.003 -50 to -25%

1006 * 1910 2015 0.004 0.002 -0.002 -100 to -50%

1007 1908 2014 0.044 0.037 -0.007 -25 to -10%

1008 1907 2015 0.020 0.015 -0.005 -25 to -10%

1009 * 1920 2013 0.025 0.009 -0.016 -100 to -50%

1010 1939 2013 0.007 0.005 -0.002 -25 to -10%

1011 1905 2012 0.016 0.012 -0.004 -25 to -10%

1012 1930 2014 0.003 0.006 0.003 50 to 100%

1013 1909 2014 0.016 0.014 -0.002 -25 to -10%

1014 1932 2013 0.006 0.007 0.001 10 to 25%

1015 1939 2013 0.004 0.007 0.003 50 to 100%

1016 * 1944 2013 0.002 0.006 0.004 > 100%

1017 1946 2013 0.012 0.024 0.012 > 100%

1018 * 1905 2015 0.014 0.007 -0.008 -100 to -50%

1019 * 1896 2015 0.015 0.007 -0.009 -100 to -50%
MRG&P Report No. 34 207

HUC4 p < 0.05 

Year Water Yield [m3/s/km2] Change in Water Yield 

Min Max Min Year Max Year [m3/s/km2] %Change 

1020 * 1938 2015 -0.001 0.020 0.021 > 100%

1021 1937 2013 0.022 0.027 0.005 10 to 25%

1022 1946 2013 0.015 0.020 0.005 25 to 50%

1023 1929 2015 0.022 0.030 0.008 25 to 50%

1024 * 1923 2015 0.038 0.071 0.033 50 to 100%

1025 * 1929 2015 0.003 0.000 -0.003 -100 to -50%

1026 * 1919 2015 0.004 0.001 -0.002 -100 to -50%

1027 * 1918 2015 0.007 0.037 0.030 > 100%

1028 * 1922 2015 0.062 0.110 0.049 50 to 100%

1029 1919 2014 0.086 0.108 0.022 25 to 50%

1030 * 1926 2014 0.000 0.181 0.181 > 100%

1101 1922 2015 0.102 0.117 0.015 10 to 25%

1102 * 1897 2015 0.008 0.004 -0.003 -50 to -25%

1103 1903 2015 0.002 0.004 0.002 50 to 100%

1104 * 1943 2015 0.001 0.000 -0.001 -100 to -50%

1105 1935 2015 0.020 0.017 -0.002 -25 to -10%

1106 1937 2015 0.020 0.024 0.004 10 to 25%

1107 * 1922 2015 0.056 0.094 0.038 50 to 100%

1108 1908 2015 0.004 0.002 -0.002 -50 to -25%

1109 * 1939 2015 0.021 0.004 -0.017 -100 to -50%

1110 * 1938 2015 0.004 0.001 -0.003 -100 to -50%

1111 * 1928 2015 0.077 0.193 0.116 > 100%

1112 * 1905 2015 0.022 0.004 -0.017 -100 to -50%

1113 1936 2015 0.019 0.014 -0.005 -50 to -25%

1114 1925 2015 0.107 0.115 0.008 5 to 10%

 
MRG&P Report No. 34 208

Table F-9. Change in maximum daily summer water yield by HUC-4. 

HUC4 p < 0.05 

Year Water Yield [m3/s/km2] Change in Water Yield 

Min Max Min Year Max Year [m3/s/km2] %Change 

0501 1909 2014 0.042 0.052 0.010 10 to 25%

0502 1908 2014 0.095 0.074 -0.021 -25 to -10%

0503 1913 2014 0.036 0.052 0.015 25 to 50%

0504 * 1922 2014 0.026 0.051 0.025 50 to 100%

0505 1896 2014 0.055 0.050 -0.005 -10 to -5%

0506 1922 2014 0.034 0.061 0.027 50 to 100%

0507 1916 2014 0.035 0.043 0.008 10 to 25%

0508 1915 2014 0.038 0.058 0.020 50 to 100%

0509 1916 2014 0.047 0.069 0.022 25 to 50%

0510 1916 2014 0.056 0.053 -0.002 -5 to 0%

0511 1928 2014 0.048 0.052 0.003 5 to 10%

0512 * 1910 2014 0.025 0.060 0.035 > 100%

0513 1915 2015 0.045 0.054 0.009 10 to 25%

0514 * 1929 2014 0.027 0.104 0.077 > 100%

0601 1900 2015 0.059 0.050 -0.009 -25 to -10%

0602 * 1899 2014 0.061 0.037 -0.023 -50 to -25%

0603 1905 2014 0.039 0.041 0.002 5 to 10%

0604 1921 2014 0.032 0.036 0.004 10 to 25%

0701 * 1907 2014 0.006 0.013 0.007 > 100%

0702 * 1912 2014 -0.001 0.018 0.019 > 100%

0703 1914 2014 0.017 0.025 0.008 25 to 50%

0704 1912 2014 0.022 0.030 0.008 25 to 50%

0705 1914 2014 0.033 0.024 -0.009 -50 to -25%

0706 1920 2014 0.046 0.048 0.001 0 to 5%

0707 1913 2013 0.030 0.025 -0.004 -25 to -10%

0708 * 1903 2014 0.013 0.056 0.043 > 100%

0709 * 1915 2014 0.013 0.028 0.015 > 100%

0710 * 1916 2014 0.016 0.042 0.026 > 100%

0711 1923 2014 0.088 0.088 0.001 0 to 5%
MRG&P Report No. 34 209

HUC4 p < 0.05 

Year Water Yield [m3/s/km2] Change in Water Yield 

Min Max Min Year Max Year [m3/s/km2] %Change 

0712 * 1916 2015 0.007 0.074 0.067 > 100%

0713 * 1909 2014 0.028 0.050 0.021 50 to 100%

0714 * 1909 2014 0.025 0.058 0.034 > 100%

0801 1930 2015 0.042 0.052 0.009 10 to 25%

0802 * 1927 2015 0.017 0.030 0.014 50 to 100%

0803 * 1909 2015 0.026 0.052 0.026 50 to 100%

0804 1929 2015 0.024 0.034 0.010 25 to 50%

0805 1939 2012 0.021 0.021 0.000 -5 to 0%

0806 1939 2015 0.043 0.044 0.001 0 to 5%

0807 1941 2015 0.054 0.062 0.008 10 to 25%

0808 1923 2015 0.046 0.024 -0.023 -50 to -25%

0809 *

1002 * 1895 2014 0.017 0.023 0.006 25 to 50%

1003 * 1903 2015 0.024 0.011 -0.014 -100 to -50%

1004 * 1908 2013 0.012 0.003 -0.009 -100 to -50%

1005 1904 2013 0.002 0.003 0.001 25 to 50%

1006 1910 2015 0.002 0.002 -0.001 -50 to -25%

1007 1908 2014 0.069 0.057 -0.012 -25 to -10%

1008 * 1907 2015 0.042 0.020 -0.022 -100 to -50%

1009 * 1920 2013 0.033 0.007 -0.027 -100 to -50%

1010 1939 2013 0.009 0.005 -0.003 -50 to -25%

1011 * 1905 2012 0.011 0.001 -0.009 -100 to -50%

1012 1930 2014 0.004 0.005 0.001 10 to 25%

1013 * 1909 2014 0.006 0.003 -0.004 -100 to -50%

1014 1932 2013 0.004 0.004 -0.001 -25 to -10%

1015 * 1939 2013 0.002 0.004 0.002 50 to 100%

1016 * 1944 2013 0.000 0.002 0.002 > 100%

1017 * 1946 2013 0.004 0.011 0.007 > 100%

1018 * 1905 2015 0.014 0.007 -0.008 -100 to -50%

1019 * 1896 2015 0.021 0.007 -0.014 -100 to -50%
MRG&P Report No. 34 210

HUC4 p < 0.05 

Year Water Yield [m3/s/km2] Change in Water Yield 

Min Max Min Year Max Year [m3/s/km2] %Change 

1020 * 1938 2015 0.002 0.017 0.014 > 100%

1021 1937 2013 0.027 0.026 -0.002 -10 to -5%

1022 1946 2013 0.018 0.019 0.001 5 to 10%

1023 1929 2015 0.023 0.026 0.003 10 to 25%

1024 1923 2015 0.053 0.062 0.010 10 to 25%

1025 * 1929 2015 0.007 0.000 -0.006 -100 to -50%

1026 * 1919 2015 0.009 0.001 -0.008 -100 to -50%

1027 * 1918 2015 0.013 0.039 0.026 > 100%

1028 1922 2015 0.079 0.077 -0.002 -5 to 0%

1029 1919 2014 0.054 0.053 -0.001 -5 to 0%

1030 * 1926 2014 0.002 0.152 0.150 > 100%

1101 1922 2015 0.030 0.023 -0.007 -25 to -10%

1102 * 1897 2015 0.015 0.006 -0.009 -100 to -50%

1103 1903 2015 0.004 0.006 0.002 25 to 50%

1104 * 1943 2015 0.009 -0.001 -0.010 > -100%

1105 1935 2015 0.015 0.009 -0.006 -50 to -25%

1106 1937 2015 0.020 0.021 0.001 5 to 10%

1107 1922 2015 0.052 0.052 0.000 -5 to 0%

1108 * 1908 2015 0.008 0.003 -0.005 -100 to -50%

1109 * 1939 2015 0.013 0.003 -0.010 -100 to -50%

1110 * 1938 2015 0.006 0.000 -0.006 -100 to -50%

1111 1928 2015 0.024 0.048 0.024 > 100%

1112 * 1905 2015 0.027 0.003 -0.024 -100 to -50%

1113 * 1936 2015 0.017 0.008 -0.009 -100 to -50%

1114 1925 2015 0.031 0.034 0.003 5 to 10%

 
MRG&P Report No. 34 211

Table F-10. Change in maximum daily fall water yield by HUC-4. 

HUC4 p < 0.05 

Year Water Yield [m3/s/km2] Change in Water Yield 

Min Max Min Year Max Year [m3/s/km2] %Change 

0501 1909 2014 0.054 0.062 0.008 10 to 25%

0502 1908 2014 0.079 0.071 -0.007 -10 to -5%

0503 1913 2014 0.031 0.036 0.006 10 to 25%

0504 * 1922 2014 0.014 0.033 0.019 > 100%

0505 1896 2014 0.063 0.053 -0.010 -25 to -10%

0506 * 1922 2014 0.012 0.032 0.020 > 100%

0507 1916 2014 0.019 0.041 0.022 > 100%

0508 1915 2014 0.018 0.029 0.011 50 to 100%

0509 1916 2014 0.025 0.057 0.032 > 100%

0510 * 1916 2014 0.025 0.058 0.033 > 100%

0511 * 1928 2014 0.029 0.063 0.034 > 100%

0512 1910 2014 0.020 0.035 0.015 50 to 100%

0513 * 1915 2015 0.043 0.087 0.043 50 to 100%

0514 * 1929 2014 0.009 0.106 0.097 > 100%

0601 * 1900 2015 0.047 0.072 0.024 50 to 100%

0602 1899 2014 0.049 0.055 0.006 10 to 25%

0603 * 1905 2014 0.029 0.078 0.049 > 100%

0604 * 1921 2014 0.030 0.069 0.039 > 100%

0701 * 1907 2014 0.003 0.008 0.004 > 100%

0702 * 1912 2014 0.000 0.004 0.004 > 100%

0703 * 1914 2014 0.010 0.016 0.006 50 to 100%

0704 * 1912 2014 0.007 0.015 0.008 > 100%

0705 1914 2014 0.018 0.022 0.005 25 to 50%

0706 1920 2014 0.017 0.015 -0.002 -25 to -10%

0707 1913 2013 0.018 0.019 0.001 5 to 10%

0708 1903 2014 0.009 0.015 0.006 50 to 100%

0709 1915 2014 0.010 0.015 0.004 25 to 50%

0710 1916 2014 0.006 0.011 0.004 50 to 100%

0711 1923 2014 0.048 0.060 0.012 10 to 25%
MRG&P Report No. 34 212

HUC4 p < 0.05 

Year Water Yield [m3/s/km2] Change in Water Yield 

Min Max Min Year Max Year [m3/s/km2] %Change 

0712 * 1916 2015 0.005 0.043 0.038 > 100%

0713 1909 2014 0.013 0.017 0.004 25 to 50%

0714 * 1909 2014 0.014 0.043 0.028 > 100%

0801 * 1930 2015 0.034 0.063 0.030 50 to 100%

0802 * 1927 2015 0.010 0.038 0.028 > 100%

0803 * 1909 2015 0.002 0.073 0.071 > 100%

0804 * 1929 2015 0.021 0.041 0.021 > 100%

0805 * 1939 2012 0.011 0.028 0.017 > 100%

0806 1939 2015 0.042 0.068 0.027 50 to 100%

0807 1941 2015 0.058 0.106 0.048 50 to 100%

0808 1923 2015 0.042 0.062 0.019 25 to 50%

0809 *

1002 * 1895 2014 0.004 0.006 0.002 50 to 100%

1003 * 1903 2015 0.004 0.003 -0.001 -50 to -25%

1004 * 1908 2013 0.002 0.001 -0.001 -100 to -50%

1005 1904 2013 0.000 0.000 0.000 0 to 5%

1006 1910 2015 0.001 0.001 0.000 -50 to -25%

1007 1908 2014 0.009 0.008 -0.001 -25 to -10%

1008 1907 2015 0.005 0.004 0.000 -25 to -10%

1009 * 1920 2013 0.003 0.002 -0.001 -50 to -25%

1010 1939 2013 0.002 0.001 -0.001 -100 to -50%

1011 * 1905 2012 0.001 0.000 -0.001 -100 to -50%

1012 * 1930 2014 0.000 0.001 0.001 > 100%

1013 * 1909 2014 0.000 0.000 0.000 > 100%

1014 1932 2013 0.001 0.001 0.000 50 to 100%

1015 * 1939 2013 0.001 0.002 0.001 50 to 100%

1016 * 1944 2013 0.000 0.001 0.001 > 100%

1017 * 1946 2013 0.000 0.002 0.002 > 100%

1018 1905 2015 0.002 0.002 0.000 -10 to -5%

1019 * 1896 2015 0.004 0.002 -0.001 -50 to -25%
MRG&P Report No. 34 213

HUC4 p < 0.05 

Year Water Yield [m3/s/km2] Change in Water Yield 

Min Max Min Year Max Year [m3/s/km2] %Change 

1020 * 1938 2015 0.000 0.004 0.003 > 100%

1021 1937 2013 0.013 0.014 0.002 10 to 25%

1022 1946 2013 0.002 0.004 0.002 50 to 100%

1023 1929 2015 0.003 0.006 0.003 50 to 100%

1024 1923 2015 0.018 0.017 -0.001 -5 to 0%

1025 * 1929 2015 0.002 0.000 -0.002 > -100%

1026 * 1919 2015 0.003 0.000 -0.003 -100 to -50%

1027 1918 2015 0.005 0.010 0.005 > 100%

1028 1922 2015 0.037 0.045 0.007 10 to 25%

1029 1919 2014 0.038 0.041 0.003 5 to 10%

1030 * 1926 2014 0.004 0.077 0.072 > 100%

1101 1922 2015 0.023 0.050 0.027 > 100%

1102 1897 2015 0.003 0.002 -0.001 -50 to -25%

1103 1903 2015 0.002 0.001 -0.001 -50 to -25%

1104 * 1943 2015 0.001 0.000 -0.001 > -100%

1105 1935 2015 0.010 0.008 -0.002 -25 to -10%

1106 1937 2015 0.013 0.013 0.001 0 to 5%

1107 1922 2015 0.038 0.033 -0.005 -25 to -10%

1108 1908 2015 0.002 0.001 -0.001 -50 to -25%

1109 * 1939 2015 0.007 0.002 -0.004 -100 to -50%

1110 1938 2015 0.001 0.001 -0.001 -100 to -50%

1111 * 1928 2015 0.012 0.083 0.071 > 100%

1112 1905 2015 0.009 0.002 -0.007 -100 to -50%

1113 1936 2015 0.009 0.007 -0.002 -25 to -10%

1114 1925 2015 0.018 0.036 0.018 > 100%

Additional data on water yield trends by HUC-4 can be found in 

WYield_byHUC4_formatted.xlsx.
MRG&P Report No. 34 214

Appendix G: Precipitation-Weighted Water 

Yield Trends by HUC-4

Table G-1. Change in annual precipitation-weighted water yield by HUC-4. 

HUC4 p < 0.05 

Year 

Precipitation-Weighted Water 

Yield [m3/s/km2/100 mm] 

Change in Precipitation-Weighted 

Water Yield 

Min Max Min Year Max Year 

[m3/s/km2/100 

mm] %Change 

0501 1910 2014 0.640 0.639 -0.002 -5 to 0%

0502 1908 2014 0.664 0.656 -0.009 -5 to 0%

0503 1913 2014 0.454 0.470 0.016 0 to 5%

0504 * 1922 2014 0.389 0.454 0.065 10 to 25%

0505 1908 2014 0.524 0.548 0.024 0 to 5%

0506 * 1922 2014 0.344 0.422 0.078 10 to 25%

0507 1929 2014 0.406 0.428 0.022 5 to 10%

0508 1915 2014 0.362 0.424 0.062 10 to 25%

0509 1916 2014 0.393 0.451 0.059 10 to 25%

0510 1916 2014 0.463 0.456 -0.008 -5 to 0%

0511 1928 2014 0.549 0.559 0.010 0 to 5%

0512 * 1910 2014 0.317 0.437 0.120 25 to 50%

0513 1915 2014 0.538 0.485 -0.053 -10 to -5%

0514 1929 2014 0.437 0.469 0.032 5 to 10%

0601 1900 2014 0.636 0.567 -0.069 -25 to -10%

0602 * 1902 2014 0.645 0.532 -0.113 -25 to -10%

0603 1905 2014 0.497 0.486 -0.012 -5 to 0%

0604 1921 2014 0.483 0.461 -0.021 -5 to 0%

0701 * 1907 2014 0.169 0.268 0.099 50 to 100%

0702 * 1912 2014 0.003 0.190 0.187 > 100%

0703 1920 2014 0.390 0.392 0.002 0 to 5%

0704 * 1912 2014 0.248 0.332 0.083 25 to 50%

0705 1914 2014 0.451 0.409 -0.042 -10 to -5%

0706 * 1920 2014 0.245 0.351 0.106 25 to 50%

0707 * 1913 2013 0.455 0.371 -0.084 -25 to -10%

0708 * 1903 2014 0.200 0.343 0.143 50 to 100%

0709 * 1915 2014 0.271 0.330 0.060 10 to 25%
MRG&P Report No. 34 215

HUC4 p < 0.05 

Year 

Precipitation-Weighted Water 

Yield [m3/s/km2/100 mm] 

Change in Precipitation-Weighted 

Water Yield 

Min Max Min Year Max Year 

[m3/s/km2/100 

mm] %Change 

0710 * 1916 2014 0.132 0.306 0.173 > 100%

0711 1923 2014 0.244 0.321 0.077 25 to 50%

0712 * 1916 2014 0.300 0.453 0.153 50 to 100%

0713 * 1909 2014 0.247 0.355 0.108 25 to 50%

0714 1909 2014 0.277 0.328 0.051 10 to 25%

0801 1930 2013 0.420 0.430 0.010 0 to 5%

0802 1927 2013 0.348 0.409 0.062 10 to 25%

0803 1909 2013 0.385 0.412 0.026 5 to 10%

0804 1929 2013 0.390 0.366 -0.024 -10 to -5%

0805 * 1939 2012 0.375 0.130 -0.245 -100 to -50%

0806 1939 2009 0.390 0.389 -0.001 -5 to 0%

0807 1941 2013 0.416 0.379 -0.037 -10 to -5%

0808 1923 2013 0.445 0.343 -0.103 -25 to -10%

0809

1002 * 1911 2014 0.265 0.771 0.506 > 100%

1003 * 1903 2014 0.538 0.343 -0.195 -50 to -25%

1004 * 1910 2013 0.235 0.044 -0.191 -100 to -50%

1005 1915 2013 0.053 0.054 0.001 0 to 5%

1006 1911 2012 0.105 0.070 -0.035 -50 to -25%

1007 1908 2014 1.147 0.958 -0.190 -25 to -10%

1008 1913 2013 0.701 0.675 -0.026 -5 to 0%

1009 * 1932 2013 0.522 0.106 -0.416 -100 to -50%

1010 * 1939 2013 0.205 0.096 -0.109 -100 to -50%

1011 * 1930 2012 0.080 0.036 -0.044 -100 to -50%

1012 * 1930 2014 0.017 0.094 0.077 > 100%

1013 1910 2014 0.061 0.051 -0.010 -25 to -10%

1014 1932 2013 0.048 0.051 0.003 5 to 10%

1015 * 1939 2013 0.064 0.108 0.044 50 to 100%

1016 * 1944 2013 0.007 0.048 0.041 > 100%

1017 * 1946 2013 0.047 0.112 0.065 > 100%

1018 1905 2013 0.208 0.190 -0.018 -10 to -5%
MRG&P Report No. 34 216

HUC4 p < 0.05 

Year 

Precipitation-Weighted Water 

Yield [m3/s/km2/100 mm] 

Change in Precipitation-Weighted 

Water Yield 

Min Max Min Year Max Year 

[m3/s/km2/100 

mm] %Change 

1019 * 1898 2014 0.322 0.085 -0.237 -100 to -50%

1020 * 1938 2013 0.013 0.099 0.086 > 100%

1021 1937 2013 0.468 0.429 -0.039 -10 to -5%

1022 1946 2013 0.113 0.161 0.048 25 to 50%

1023 * 1929 2013 0.085 0.221 0.136 > 100%

1024 * 1923 2014 0.122 0.273 0.152 > 100%

1025 * 1929 2014 0.045 0.006 -0.039 -100 to -50%

1026 * 1919 2014 0.036 0.012 -0.024 -100 to -50%

1027 * 1918 2014 0.058 0.127 0.068 > 100%

1028 1922 2014 0.212 0.295 0.083 25 to 50%

1029 1919 2014 0.283 0.301 0.017 5 to 10%

1030 * 1926 2014 0.050 0.388 0.338 > 100%

1101 1922 2013 0.349 0.396 0.047 10 to 25%

1102 1897 2013 0.155 0.104 -0.051 -50 to -25%

1103 1903 2013 0.018 0.024 0.006 25 to 50%

1104 * 1943 2013 0.021 0.001 -0.020 -100 to -50%

1105 1935 2013 0.049 0.046 -0.003 -10 to -5%

1106 * 1937 2013 0.057 0.098 0.041 50 to 100%

1107 * 1922 2013 0.181 0.288 0.107 50 to 100%

1108 * 1908 2013 0.060 0.037 -0.023 -50 to -25%

1109 * 1939 2013 0.084 0.030 -0.054 -100 to -50%

1110 * 1938 2013 0.017 0.010 -0.007 -50 to -25%

1111 * 1928 2013 0.243 0.391 0.148 50 to 100%

1112 * 1938 2013 0.044 0.025 -0.019 -50 to -25%

1113 1936 2013 0.059 0.068 0.008 10 to 25%

1114 1925 2013 0.296 0.284 -0.012 -5 to 0%

 
MRG&P Report No. 34 217

Table G-2. Change in maximum annual daily precipitation-weighted water yield 

by HUC-4. 

HUC4 p < 0.05 

Year 

Precipitation-Weighted Water 

Yield [m3/s/km2/100 mm] 

Change in Precipitation-Weighted 

Water Yield 

Min Max Min Year Max Year [m3/s/km2/100 mm] %Change 

0501 * 1910 2014 0.369 0.295 -0.075 -25 to -10%

0502 1908 2014 0.506 0.418 -0.088 -25 to -10%

0503 * 1913 2014 0.371 0.270 -0.101 -50 to -25%

0504 1922 2014 0.156 0.223 0.067 25 to 50%

0505 1908 2014 0.318 0.337 0.018 5 to 10%

0506 1922 2014 0.316 0.240 -0.077 -25 to -10%

0507 * 1929 2014 0.414 0.292 -0.122 -50 to -25%

0508 1915 2014 0.266 0.257 -0.009 -5 to 0%

0509 1916 2014 0.403 0.386 -0.017 -5 to 0%

0510 1916 2014 0.338 0.386 0.048 10 to 25%

0511 * 1928 2014 0.371 0.260 -0.111 -50 to -25%

0512 * 1910 2014 0.170 0.285 0.116 50 to 100%

0513 1915 2014 0.420 0.472 0.052 10 to 25%

0514 * 1929 2014 0.256 0.575 0.319 > 100%

0601 1900 2014 0.316 0.310 -0.006 -5 to 0%

0602 1902 2014 0.279 0.224 -0.055 -25 to -10%

0603 * 1905 2014 0.242 0.460 0.217 50 to 100%

0604 1921 2014 0.342 0.359 0.017 5 to 10%

0701 * 1907 2014 0.024 0.035 0.012 25 to 50%

0702 * 1912 2014 0.010 0.056 0.046 > 100%

0703 1920 2014 0.066 0.075 0.009 10 to 25%

0704 1912 2014 0.130 0.101 -0.029 -25 to -10%

0705 1914 2014 0.119 0.105 -0.014 -25 to -10%

0706 * 1920 2014 0.216 0.152 -0.065 -50 to -25%

0707 1913 2013 0.108 0.113 0.005 0 to 5%

0708 * 1903 2014 0.050 0.157 0.107 > 100%

0709 1915 2014 0.089 0.082 -0.008 -10 to -5%

0710 * 1916 2014 0.042 0.104 0.062 > 100%

0711 * 1923 2014 0.227 0.336 0.109 25 to 50%

0712 * 1916 2014 0.051 0.243 0.192 > 100%
MRG&P Report No. 34 218

HUC4 p < 0.05 

Year 

Precipitation-Weighted Water 

Yield [m3/s/km2/100 mm] 

Change in Precipitation-Weighted 

Water Yield 

Min Max Min Year Max Year [m3/s/km2/100 mm] %Change 

0713 * 1909 2014 0.113 0.202 0.089 50 to 100%

0714 * 1909 2014 0.116 0.376 0.260 > 100%

0801 1930 2013 0.244 0.276 0.032 10 to 25%

0802 * 1927 2013 0.097 0.136 0.038 25 to 50%

0803 * 1909 2013 0.150 0.373 0.223 > 100%

0804 1929 2013 0.231 0.198 -0.032 -25 to -10%

0805 * 1939 2012 0.095 0.065 -0.031 -50 to -25%

0806 1939 2009 0.301 0.403 0.102 25 to 50%

0807 1941 2013 0.279 0.324 0.045 10 to 25%

0808 1923 2013 0.205 0.141 -0.064 -50 to -25%

0809

1002 * 1911 2014 0.063 0.121 0.058 50 to 100%

1003 * 1903 2014 0.112 0.039 -0.072 -100 to -50%

1004 * 1910 2013 0.049 0.014 -0.035 -100 to -50%

1005 1915 2013 0.027 0.021 -0.006 -25 to -10%

1006 * 1911 2012 0.018 0.006 -0.013 -100 to -50%

1007 1908 2014 0.235 0.190 -0.045 -25 to -10%

1008 1913 2013 0.152 0.101 -0.051 -50 to -25%

1009 * 1932 2013 0.130 0.020 -0.110 -100 to -50%

1010 * 1939 2013 0.033 0.020 -0.013 -50 to -25%

1011 1930 2012 0.049 0.029 -0.020 -50 to -25%

1012 1930 2014 0.017 0.018 0.001 5 to 10%

1013 1910 2014 0.053 0.033 -0.021 -50 to -25%

1014 1932 2013 0.019 0.018 -0.001 -5 to 0%

1015 * 1939 2013 0.010 0.018 0.008 50 to 100%

1016 * 1944 2013 0.004 0.015 0.010 > 100%

1017 1946 2013 0.027 0.050 0.023 50 to 100%

1018 * 1905 2013 0.056 0.027 -0.028 -100 to -50%

1019 * 1898 2014 0.061 0.028 -0.033 -100 to -50%

1020 * 1938 2013 0.003 0.060 0.057 > 100%

1021 1937 2013 0.069 0.067 -0.002 -5 to 0%

1022 1946 2013 0.044 0.047 0.003 5 to 10%
MRG&P Report No. 34 219

HUC4 p < 0.05 

Year 

Precipitation-Weighted Water 

Yield [m3/s/km2/100 mm] 

Change in Precipitation-Weighted 

Water Yield 

Min Max Min Year Max Year [m3/s/km2/100 mm] %Change 

1023 1929 2013 0.068 0.084 0.016 10 to 25%

1024 1923 2014 0.126 0.168 0.043 25 to 50%

1025 * 1929 2014 0.017 0.001 -0.015 -100 to -50%

1026 * 1919 2014 0.022 0.005 -0.016 -100 to -50%

1027 * 1918 2014 0.027 0.091 0.063 > 100%

1028 1922 2014 0.174 0.194 0.020 10 to 25%

1029 1919 2014 0.177 0.235 0.058 25 to 50%

1030 * 1926 2014 0.033 0.448 0.415 > 100%

1101 1922 2013 0.189 0.244 0.055 25 to 50%

1102 * 1897 2013 0.044 0.024 -0.020 -50 to -25%

1103 1903 2013 0.010 0.015 0.005 25 to 50%

1104 * 1943 2013 0.026 -0.003 -0.029 > -100%

1105 * 1935 2013 0.053 0.028 -0.025 -50 to -25%

1106 1937 2013 0.052 0.056 0.004 5 to 10%

1107 1922 2013 0.126 0.174 0.048 25 to 50%

1108 * 1908 2013 0.031 0.013 -0.019 -100 to -50%

1109 * 1939 2013 0.051 0.007 -0.044 -100 to -50%

1110 * 1938 2013 0.016 0.002 -0.014 -100 to -50%

1111 * 1928 2013 0.115 0.387 0.272 > 100%

1112 * 1938 2013 0.068 0.012 -0.056 -100 to -50%

1113 * 1936 2013 0.058 0.031 -0.027 -50 to -25%

1114 1925 2013 0.187 0.182 -0.005 -5 to 0%

 
MRG&P Report No. 34 220

Table G-3. Change in winter precipitation-weighted water yield by HUC-4. 

HUC4 

p < 

0.05 

Year 

Precipitation-Weighted 

Water Yield 

[m3/s/km2/100 mm] 

Change in Precipitation-Weighted 

Water Yield 

Min Max Min Year Max Year 

[m3/s/km2/100 

mm] %Change 

0501 1910 2014 0.929 1.041 0.113 10 to 25%

0502 1908 2014 1.109 1.093 -0.016 -5 to 0%

0503 1913 2014 0.733 0.797 0.064 5 to 10%

0504 1922 2014 0.587 0.750 0.163 25 to 50%

0505 1908 2014 0.821 0.821 0.000 -5 to 0%

0506 1922 2014 0.548 0.705 0.157 25 to 50%

0507 1929 2014 0.680 0.627 -0.053 -10 to -5%

0508 1915 2014 0.554 0.656 0.102 10 to 25%

0509 1916 2014 0.649 0.738 0.089 10 to 25%

0510 1916 2014 0.735 0.781 0.045 5 to 10%

0511 1928 2014 0.805 0.878 0.073 5 to 10%

0512 * 1910 2014 0.480 0.686 0.207 25 to 50%

0513 1915 2014 0.828 0.750 -0.077 -10 to -5%

0514 1929 2014 0.642 0.740 0.098 10 to 25%

0601 1900 2014 0.780 0.783 0.004 0 to 5%

0602 1902 2014 0.599 0.729 0.130 10 to 25%

0603 1905 2014 0.656 0.752 0.096 10 to 25%

0604 1921 2014 0.632 0.735 0.103 10 to 25%

0701 * 1907 2014 0.283 0.459 0.177 50 to 100%

0702 * 1912 2014 -0.028 0.157 0.185 > 100%

0703 1920 2014 0.721 0.572 -0.149 -25 to -10%

0704 1912 2014 0.413 0.465 0.053 10 to 25%

0705 1914 2014 0.763 0.784 0.021 0 to 5%

0706 1920 2014 0.455 0.482 0.026 5 to 10%

0707 1913 2013 0.736 0.664 -0.072 -10 to -5%

0708 1903 2014 0.243 0.372 0.129 50 to 100%

0709 1915 2014 0.471 0.526 0.055 10 to 25%

0710 1916 2014 0.151 0.269 0.117 50 to 100%
MRG&P Report No. 34 221

HUC4 

p < 

0.05 

Year 

Precipitation-Weighted 

Water Yield 

[m3/s/km2/100 mm] 

Change in Precipitation-Weighted 

Water Yield 

Min Max Min Year Max Year 

[m3/s/km2/100 

mm] %Change 

0711 1923 2014 0.351 0.400 0.048 10 to 25%

0712 * 1916 2014 0.497 0.683 0.186 25 to 50%

0713 1909 2014 0.410 0.499 0.088 10 to 25%

0714 1909 2014 0.365 0.466 0.101 25 to 50%

0801 1930 2013 0.575 0.586 0.011 0 to 5%

0802 * 1927 2013 0.409 0.569 0.159 25 to 50%

0803 * 1909 2013 0.394 0.587 0.193 25 to 50%

0804 1929 2013 0.511 0.528 0.018 0 to 5%

0805 * 1939 2012 0.456 0.186 -0.270 -100 to -50%

0806 1939 2009 0.475 0.545 0.070 10 to 25%

0807 1941 2013 0.590 0.532 -0.059 -10 to -5%

0808 1923 2013 0.598 0.587 -0.011 -5 to 0%

0809

1002 * 1911 2014 0.147 0.987 0.840 > 100%

1003 * 1903 2014 0.403 0.596 0.194 25 to 50%

1004 * 1910 2013 0.168 0.078 -0.091 -100 to -50%

1005 * 1915 2013 0.015 0.042 0.027 > 100%

1006 * 1911 2012 0.050 0.273 0.224 > 100%

1007 1908 2014 0.622 0.637 0.015 0 to 5%

1008 1913 2013 0.584 0.634 0.051 5 to 10%

1009 * 1932 2013 0.298 0.170 -0.128 -50 to -25%

1010 1939 2013 0.277 0.220 -0.057 -25 to -10%

1011 1930 2012 0.020 0.016 -0.003 -25 to -10%

1012 * 1930 2014 -0.021 0.142 0.163 > 100%

1013 * 1910 2014 0.009 0.032 0.023 > 100%

1014 * 1932 2013 0.039 0.112 0.073 > 100%

1015 * 1939 2013 0.200 0.405 0.205 > 100%

1016 * 1944 2013 -0.004 0.025 0.029 > 100%
MRG&P Report No. 34 222

HUC4 

p < 

0.05 

Year 

Precipitation-Weighted 

Water Yield 

[m3/s/km2/100 mm] 

Change in Precipitation-Weighted 

Water Yield 

Min Max Min Year Max Year 

[m3/s/km2/100 

mm] %Change 

1017 * 1946 2013 0.026 0.087 0.061 > 100%

1018 * 1905 2013 0.127 0.179 0.052 25 to 50%

1019 1898 2014 0.175 0.171 -0.004 -5 to 0%

1020 * 1938 2013 0.035 0.217 0.182 > 100%

1021 1937 2013 1.514 1.742 0.228 10 to 25%

1022 * 1946 2013 0.184 0.388 0.204 > 100%

1023 * 1929 2013 0.058 0.368 0.310 > 100%

1024 1923 2014 0.217 0.332 0.115 50 to 100%

1025 * 1929 2014 0.100 0.021 -0.079 -100 to -50%

1026 1919 2014 0.038 0.028 -0.010 -50 to -25%

1027 * 1918 2014 0.078 0.181 0.103 > 100%

1028 1922 2014 0.291 0.362 0.071 10 to 25%

1029 1919 2014 0.514 0.417 -0.097 -25 to -10%

1030 * 1926 2014 0.059 0.392 0.333 > 100%

1101 1922 2013 0.430 0.522 0.092 10 to 25%

1102 1897 2013 0.190 0.152 -0.038 -25 to -10%

1103 1903 2013 0.024 0.033 0.009 25 to 50%

1104 * 1943 2013 0.043 -0.001 -0.044 > -100%

1105 * 1935 2013 0.027 0.067 0.040 > 100%

1106 * 1937 2013 0.032 0.150 0.117 > 100%

1107 * 1922 2013 0.164 0.372 0.208 > 100%

1108 * 1908 2013 0.064 0.026 -0.039 -100 to -50%

1109 1939 2013 0.088 0.051 -0.037 -50 to -25%

1110 1938 2013 0.016 0.023 0.007 25 to 50%

1111 1928 2013 0.350 0.522 0.171 25 to 50%

1112 * 1938 2013 0.021 0.074 0.053 > 100%

1113 * 1936 2013 0.030 0.090 0.060 > 100%

1114 1925 2013 0.363 0.391 0.028 5 to 10%
MRG&P Report No. 34 223

Table G-4. Change in spring precipitation-weighted water yield by HUC-4. 

HUC4 

p < 

0.05 

Year 

Precipitation-Weighted 

Water Yield 

[m3/s/km2/100 mm] 

Change in Precipitation-Weighted 

Water Yield 

Min Max Min Year Max Year 

[m3/s/km2/100 

mm] %Change 

0501 * 1910 2014 1.099 0.929 -0.170 -25 to -10%

0502 1908 2014 0.994 0.911 -0.083 -10 to -5%

0503 1913 2014 0.710 0.653 -0.056 -10 to -5%

0504 1922 2014 0.584 0.636 0.051 5 to 10%

0505 1908 2014 0.732 0.794 0.061 5 to 10%

0506 1922 2014 0.495 0.587 0.092 10 to 25%

0507 1929 2014 0.685 0.641 -0.045 -10 to -5%

0508 1915 2014 0.493 0.562 0.069 10 to 25%

0509 1916 2014 0.571 0.636 0.064 10 to 25%

0510 1916 2014 0.695 0.635 -0.060 -10 to -5%

0511 * 1928 2014 0.813 0.624 -0.189 -25 to -10%

0512 * 1910 2014 0.468 0.575 0.106 10 to 25%

0513 * 1915 2014 0.767 0.632 -0.135 -25 to -10%

0514 1929 2014 0.646 0.615 -0.031 -5 to 0%

0601 * 1900 2014 0.829 0.743 -0.086 -25 to -10%

0602 * 1902 2014 0.831 0.596 -0.235 -50 to -25%

0603 1905 2014 0.672 0.605 -0.067 -10 to -5%

0604 1921 2014 0.654 0.539 -0.114 -25 to -10%

0701 * 1907 2014 0.262 0.438 0.176 50 to 100%

0702 * 1912 2014 0.037 0.362 0.325 > 100%

0703 1920 2014 0.646 0.646 0.000 -5 to 0%

0704 1912 2014 0.423 0.482 0.059 10 to 25%

0705 1914 2014 0.716 0.552 -0.164 -25 to -10%

0706 1920 2014 0.359 0.462 0.103 25 to 50%

0707 * 1913 2013 0.739 0.527 -0.212 -50 to -25%

0708 * 1903 2014 0.301 0.484 0.183 50 to 100%

0709 1915 2014 0.425 0.464 0.039 5 to 10%

0710 * 1916 2014 0.242 0.397 0.155 50 to 100%
MRG&P Report No. 34 224

HUC4 

p < 

0.05 

Year 

Precipitation-Weighted 

Water Yield 

[m3/s/km2/100 mm] 

Change in Precipitation-Weighted 

Water Yield 

Min Max Min Year Max Year 

[m3/s/km2/100 

mm] %Change 

0711 * 1923 2014 0.299 0.460 0.161 50 to 100%

0712 * 1916 2014 0.477 0.647 0.170 25 to 50%

0713 * 1909 2014 0.362 0.497 0.135 25 to 50%

0714 1909 2014 0.388 0.438 0.050 10 to 25%

0801 1930 2013 0.529 0.521 -0.008 -5 to 0%

0802 1927 2013 0.508 0.509 0.000 0 to 5%

0803 1909 2013 0.550 0.450 -0.100 -25 to -10%

0804 1929 2013 0.561 0.474 -0.087 -25 to -10%

0805 * 1939 2012 0.539 0.110 -0.429 -100 to -50%

0806 1939 2009 0.527 0.517 -0.009 -5 to 0%

0807 1941 2013 0.546 0.503 -0.044 -10 to -5%

0808 1923 2013 0.572 0.476 -0.096 -25 to -10%

0809 *

1002 * 1911 2014 0.367 0.753 0.386 > 100%

1003 * 1903 2014 0.710 0.268 -0.442 -100 to -50%

1004 * 1910 2013 0.352 0.025 -0.327 -100 to -50%

1005 1915 2013 0.134 0.077 -0.058 -50 to -25%

1006 1911 2012 0.160 0.089 -0.071 -50 to -25%

1007 * 1908 2014 0.839 0.580 -0.259 -50 to -25%

1008 1913 2013 0.524 0.426 -0.098 -25 to -10%

1009 * 1932 2013 0.511 0.093 -0.418 -100 to -50%

1010 * 1939 2013 0.236 0.096 -0.139 -100 to -50%

1011 1930 2012 0.155 0.099 -0.056 -50 to -25%

1012 * 1930 2014 0.030 0.093 0.063 > 100%

1013 1910 2014 0.149 0.104 -0.045 -50 to -25%

1014 1932 2013 0.066 0.079 0.014 10 to 25%

1015 1939 2013 0.088 0.124 0.036 25 to 50%

1016 * 1944 2013 0.027 0.078 0.050 > 100%
MRG&P Report No. 34 225

HUC4 

p < 

0.05 

Year 

Precipitation-Weighted 

Water Yield 

[m3/s/km2/100 mm] 

Change in Precipitation-Weighted 

Water Yield 

Min Max Min Year Max Year 

[m3/s/km2/100 

mm] %Change 

1017 1946 2013 0.093 0.196 0.104 > 100%

1018 1905 2013 0.240 0.194 -0.045 -25 to -10%

1019 * 1898 2014 0.242 0.098 -0.144 -100 to -50%

1020 * 1938 2013 0.012 0.113 0.100 > 100%

1021 1937 2013 0.503 0.426 -0.078 -25 to -10%

1022 1946 2013 0.156 0.193 0.037 10 to 25%

1023 * 1929 2013 0.136 0.271 0.135 50 to 100%

1024 * 1923 2014 0.139 0.330 0.191 > 100%

1025 * 1929 2014 0.043 0.004 -0.039 -100 to -50%

1026 * 1919 2014 0.025 0.014 -0.011 -50 to -25%

1027 * 1918 2014 0.058 0.137 0.079 > 100%

1028 * 1922 2014 0.269 0.429 0.160 50 to 100%

1029 1919 2014 0.402 0.402 -0.001 -5 to 0%

1030 * 1926 2014 0.057 0.492 0.436 > 100%

1101 1922 2013 0.496 0.531 0.035 5 to 10%

1102 1897 2013 0.125 0.117 -0.007 -10 to -5%

1103 1903 2013 0.012 0.024 0.012 > 100%

1104 * 1943 2013 0.015 0.001 -0.014 -100 to -50%

1105 1935 2013 0.052 0.054 0.002 0 to 5%

1106 * 1937 2013 0.064 0.112 0.047 50 to 100%

1107 * 1922 2013 0.211 0.383 0.172 50 to 100%

1108 1908 2013 0.072 0.041 -0.031 -50 to -25%

1109 * 1939 2013 0.116 0.026 -0.090 -100 to -50%

1110 1938 2013 0.015 0.014 -0.001 -10 to -5%

1111 * 1928 2013 0.358 0.510 0.151 25 to 50%

1112 1938 2013 0.042 0.033 -0.009 -25 to -10%

1113 1936 2013 0.064 0.060 -0.004 -10 to -5%

1114 1925 2013 0.459 0.390 -0.069 -25 to -10%

 
MRG&P Report No. 34 226

Table G-5. Change in summer precipitation-weighted water yield by HUC-4. 

HUC4 

p < 

0.05 

Year 

Precipitation-Weighted 

Water Yield 

[m3/s/km2/100 mm] 

Change in Precipitation-Weighted 

Water Yield 

Min Max Min Year Max Year 

[m3/s/km2/100 

mm] %Change 

0501 * 1910 2014 0.191 0.277 0.086 25 to 50%

0502 1908 2014 0.273 0.270 -0.003 -5 to 0%

0503 * 1913 2014 0.130 0.237 0.107 50 to 100%

0504 * 1922 2014 0.155 0.232 0.078 50 to 100%

0505 1908 2014 0.256 0.265 0.009 0 to 5%

0506 * 1922 2014 0.110 0.222 0.112 > 100%

0507 * 1929 2014 0.101 0.196 0.095 50 to 100%

0508 * 1915 2014 0.171 0.256 0.086 50 to 100%

0509 1916 2014 0.146 0.190 0.044 25 to 50%

0510 1916 2014 0.154 0.162 0.009 5 to 10%

0511 1928 2014 0.213 0.236 0.022 10 to 25%

0512 * 1910 2014 0.141 0.240 0.099 50 to 100%

0513 1915 2014 0.202 0.188 -0.014 -10 to -5%

0514 1929 2014 0.160 0.213 0.053 25 to 50%

0601 1900 2014 0.430 0.348 -0.082 -25 to -10%

0602 1902 2014 0.511 0.420 -0.091 -25 to -10%

0603 * 1905 2014 0.256 0.174 -0.081 -50 to -25%

0604 1921 2014 0.235 0.214 -0.020 -10 to -5%

0701 * 1907 2014 0.115 0.168 0.053 25 to 50%

0702 * 1912 2014 -0.019 0.148 0.167 > 100%

0703 1920 2014 0.215 0.240 0.025 10 to 25%

0704 * 1912 2014 0.133 0.222 0.089 50 to 100%

0705 1914 2014 0.246 0.231 -0.015 -10 to -5%

0706 * 1920 2014 0.143 0.257 0.114 50 to 100%

0707 1913 2013 0.259 0.217 -0.042 -25 to -10%

0708 * 1903 2014 0.136 0.274 0.139 > 100%

0709 * 1915 2014 0.136 0.223 0.087 50 to 100%

0710 * 1916 2014 0.086 0.285 0.198 > 100%
MRG&P Report No. 34 227

HUC4 

p < 

0.05 

Year 

Precipitation-Weighted 

Water Yield 

[m3/s/km2/100 mm] 

Change in Precipitation-Weighted 

Water Yield 

Min Max Min Year Max Year 

[m3/s/km2/100 

mm] %Change 

0711 1923 2014 0.164 0.186 0.022 10 to 25%

0712 * 1916 2014 0.127 0.294 0.167 > 100%

0713 1909 2014 0.154 0.221 0.067 25 to 50%

0714 1909 2014 0.153 0.173 0.020 10 to 25%

0801 1930 2013 0.209 0.251 0.042 10 to 25%

0802 1927 2013 0.199 0.212 0.013 5 to 10%

0803 1909 2013 0.225 0.202 -0.023 -25 to -10%

0804 1929 2013 0.125 0.159 0.033 25 to 50%

0805 1939 2012 0.139 0.118 -0.021 -25 to -10%

0806 1939 2009 0.195 0.159 -0.036 -25 to -10%

0807 1941 2013 0.206 0.163 -0.043 -25 to -10%

0808 * 1923 2013 0.217 0.121 -0.096 -50 to -25%

0809 *

1002 * 1911 2014 0.291 0.827 0.536 > 100%

1003 * 1903 2014 0.524 0.282 -0.243 -50 to -25%

1004 * 1910 2013 0.187 0.067 -0.119 -100 to -50%

1005 * 1915 2013 0.022 0.043 0.021 50 to 100%

1006 1911 2012 0.041 0.042 0.000 0 to 5%

1007 1908 2014 2.026 1.847 -0.179 -10 to -5%

1008 1913 2013 1.280 1.249 -0.030 -5 to 0%

1009 * 1932 2013 0.637 0.156 -0.482 -100 to -50%

1010 1939 2013 0.193 0.123 -0.070 -50 to -25%

1011 * 1930 2012 0.045 0.005 -0.040 -100 to -50%

1012 * 1930 2014 0.014 0.075 0.062 > 100%

1013 1910 2014 0.026 0.019 -0.008 -50 to -25%

1014 1932 2013 0.031 0.028 -0.002 -10 to -5%

1015 * 1939 2013 0.031 0.063 0.032 > 100%

1016 * 1944 2013 -0.002 0.038 0.039 > 100%
MRG&P Report No. 34 228

HUC4 

p < 

0.05 

Year 

Precipitation-Weighted 

Water Yield 

[m3/s/km2/100 mm] 

Change in Precipitation-Weighted 

Water Yield 

Min Max Min Year Max Year 

[m3/s/km2/100 

mm] %Change 

1017 * 1946 2013 0.024 0.082 0.058 > 100%

1018 1905 2013 0.250 0.195 -0.054 -25 to -10%

1019 * 1898 2014 0.523 0.028 -0.495 -100 to -50%

1020 * 1938 2013 0.004 0.079 0.074 > 100%

1021 1937 2013 0.231 0.239 0.009 0 to 5%

1022 1946 2013 0.076 0.108 0.032 25 to 50%

1023 * 1929 2013 0.057 0.182 0.125 > 100%

1024 * 1923 2014 0.093 0.208 0.115 > 100%

1025 * 1929 2014 0.037 0.003 -0.035 -100 to -50%

1026 * 1919 2014 0.040 0.006 -0.034 -100 to -50%

1027 * 1918 2014 0.054 0.105 0.051 50 to 100%

1028 1922 2014 0.151 0.209 0.058 25 to 50%

1029 1919 2014 0.166 0.174 0.008 0 to 5%

1030 * 1926 2014 0.048 0.248 0.200 > 100%

1101 1922 2013 0.238 0.234 -0.004 -5 to 0%

1102 * 1897 2013 0.173 0.068 -0.105 -100 to -50%

1103 1903 2013 0.020 0.019 -0.001 -10 to -5%

1104 * 1943 2013 0.021 -0.002 -0.023 > -100%

1105 1935 2013 0.042 0.032 -0.010 -25 to -10%

1106 1937 2013 0.048 0.072 0.024 25 to 50%

1107 1922 2013 0.151 0.192 0.041 25 to 50%

1108 * 1908 2013 0.054 0.023 -0.031 -100 to -50%

1109 * 1939 2013 0.052 0.020 -0.031 -100 to -50%

1110 * 1938 2013 0.017 0.009 -0.008 -50 to -25%

1111 1928 2013 0.095 0.153 0.059 50 to 100%

1112 * 1938 2013 0.042 0.012 -0.030 -100 to -50%

1113 1936 2013 0.068 0.043 -0.025 -50 to -25%

1114 1925 2013 0.125 0.115 -0.011 -10 to -5%
MRG&P Report No. 34 229

Table G-6. Change in fall precipitation-weighted water yield by HUC-4. 

HUC4 p < 0.05 

Year 

Precipitation-Weighted Water 

Yield [m3/s/km2/100 mm] 

Change in Precipitation-Weighted 

Water Yield 

Min Max Min Year Max Year [m3/s/km2/100 mm] %Change 

0501 1910 2014 0.325 0.393 0.068 10 to 25%

0502 1908 2014 0.354 0.366 0.011 0 to 5%

0503 * 1913 2014 0.163 0.260 0.097 50 to 100%

0504 * 1922 2014 0.130 0.230 0.100 50 to 100%

0505 1908 2014 0.296 0.329 0.033 10 to 25%

0506 * 1922 2014 0.057 0.193 0.135 > 100%

0507 * 1929 2014 0.083 0.215 0.132 > 100%

0508 1915 2014 0.136 0.179 0.043 25 to 50%

0509 * 1916 2014 0.074 0.208 0.135 > 100%

0510 * 1916 2014 0.090 0.208 0.118 > 100%

0511 * 1928 2014 0.132 0.351 0.219 > 100%

0512 1910 2014 0.110 0.165 0.055 50 to 100%

0513 1915 2014 0.173 0.226 0.053 25 to 50%

0514 * 1929 2014 0.096 0.210 0.114 > 100%

0601 1900 2014 0.486 0.398 -0.088 -25 to -10%

0602 * 1902 2014 0.536 0.398 -0.138 -50 to -25%

0603 1905 2014 0.218 0.223 0.005 0 to 5%

0604 1921 2014 0.219 0.245 0.026 10 to 25%

0701 1907 2014 0.176 0.209 0.034 10 to 25%

0702 * 1912 2014 -0.005 0.073 0.078 > 100%

0703 1920 2014 0.328 0.329 0.001 0 to 5%

0704 * 1912 2014 0.189 0.269 0.081 25 to 50%

0705 1914 2014 0.410 0.355 -0.055 -25 to -10%

0706 * 1920 2014 0.143 0.258 0.115 50 to 100%

0707 1913 2013 0.353 0.293 -0.060 -25 to -10%

0708 1903 2014 0.135 0.141 0.007 0 to 5%

0709 * 1915 2014 0.154 0.255 0.101 50 to 100%

0710 * 1916 2014 0.074 0.133 0.059 50 to 100%

0711 1923 2014 0.122 0.128 0.006 5 to 10%

0712 * 1916 2014 0.132 0.295 0.163 > 100%

0713 1909 2014 0.086 0.105 0.019 10 to 25%
MRG&P Report No. 34 230

HUC4 p < 0.05 

Year 

Precipitation-Weighted Water 

Yield [m3/s/km2/100 mm] 

Change in Precipitation-Weighted 

Water Yield 

Min Max Min Year Max Year [m3/s/km2/100 mm] %Change 

0714 1909 2014 0.105 0.118 0.013 10 to 25%

0801 * 1930 2013 0.175 0.247 0.072 25 to 50%

0802 * 1927 2013 0.112 0.189 0.077 50 to 100%

0803 * 1909 2013 0.132 0.225 0.094 50 to 100%

0804 1929 2013 0.127 0.128 0.001 0 to 5%

0805 1939 2012 0.086 0.085 0.000 -5 to 0%

0806 1939 2009 0.168 0.163 -0.005 -5 to 0%

0807 1941 2013 0.249 0.223 -0.026 -25 to -10%

0808 1923 2013 0.226 0.180 -0.046 -25 to -10%

0809 *

1002 * 1911 2014 0.205 0.547 0.342 > 100%

1003 1903 2014 0.347 0.364 0.017 0 to 5%

1004 * 1910 2013 0.112 0.040 -0.072 -100 to -50%

1005 * 1915 2013 0.011 0.025 0.013 > 100%

1006 1911 2012 0.116 0.069 -0.047 -50 to -25%

1007 1908 2014 0.606 0.476 -0.130 -25 to -10%

1008 1913 2013 0.415 0.431 0.016 0 to 5%

1009 * 1932 2013 0.282 0.085 -0.197 -100 to -50%

1010 * 1939 2013 0.218 0.060 -0.158 -100 to -50%

1011 * 1930 2012 0.018 0.006 -0.012 -100 to -50%

1012 * 1930 2014 -0.001 0.083 0.084 > 100%

1013 * 1910 2014 0.008 0.016 0.008 > 100%

1014 1932 2013 0.027 0.024 -0.003 -25 to -10%

1015 1939 2013 0.067 0.099 0.032 25 to 50%

1016 * 1944 2013 -0.005 0.023 0.027 > 100%

1017 * 1946 2013 0.015 0.049 0.034 > 100%

1018 1905 2013 0.115 0.098 -0.017 -25 to -10%

1019 * 1898 2014 0.192 0.076 -0.116 -100 to -50%

1020 * 1938 2013 0.008 0.066 0.058 > 100%

1021 1937 2013 0.565 0.512 -0.053 -10 to -5%

1022 1946 2013 0.074 0.100 0.026 25 to 50%

1023 * 1929 2013 0.051 0.134 0.083 > 100%
MRG&P Report No. 34 231

HUC4 p < 0.05 

Year 

Precipitation-Weighted Water 

Yield [m3/s/km2/100 mm] 

Change in Precipitation-Weighted 

Water Yield 

Min Max Min Year Max Year [m3/s/km2/100 mm] %Change 

1024 * 1923 2014 0.063 0.134 0.071 > 100%

1025 * 1929 2014 0.038 0.004 -0.034 -100 to -50%

1026 * 1919 2014 0.025 0.006 -0.019 -100 to -50%

1027 1918 2014 0.044 0.058 0.014 25 to 50%

1028 1922 2014 0.108 0.137 0.029 25 to 50%

1029 1919 2014 0.147 0.122 -0.025 -25 to -10%

1030 * 1926 2014 0.022 0.188 0.166 > 100%

1101 1922 2013 0.207 0.186 -0.022 -25 to -10%

1102 1897 2013 0.116 0.098 -0.018 -25 to -10%

1103 1903 2013 0.014 0.014 0.000 0 to 5%

1104 * 1943 2013 0.016 0.000 -0.016 > -100%

1105 1935 2013 0.032 0.032 0.000 -5 to 0%

1106 1937 2013 0.045 0.056 0.010 10 to 25%

1107 1922 2013 0.112 0.117 0.004 0 to 5%

1108 1908 2013 0.044 0.029 -0.015 -50 to -25%

1109 * 1939 2013 0.038 0.011 -0.027 -100 to -50%

1110 1938 2013 0.008 0.007 -0.001 -25 to -10%

1111 * 1928 2013 0.065 0.160 0.095 > 100%

1112 1938 2013 0.017 0.017 0.000 -5 to 0%

1113 1936 2013 0.031 0.039 0.008 25 to 50%

1114 1925 2013 0.082 0.093 0.012 10 to 25%
MRG&P Report No. 34 232

Appendix H: Stream flow Trends at Index 

Stations

Table H-1. Change in annual streamflow at index stations with significant trends. 

Station River HUC4 

Year Streamflow [m3/s] Change in Streamflow 

Min Max Min Year Max Year [m3/s] %Change 

03025500 Allegheny 0501 1915 2013 101,931 119,675 17,744 10 to 25%

03031500 Allegheny 0501 1933 2013 129,318 155,379 26,061 10 to 25%

03144500 Muskingum 0504 1922 2014 59,749 77,465 17,716 25 to 50%

03150000 Muskingum 0504 1922 2014 70,042 93,834 23,792 25 to 50%

03193000 Kanawha 0505 1878 2012 137,361 118,673 -18,688 -25 to -10%

03221000 Scioto 0506 1922 2013 6,935 10,555 3,620 50 to 100%

03227500 Scioto 0506 1921 2013 12,392 18,398 6,007 25 to 50%

03231500 Scioto 0506 1921 2014 31,894 43,590 11,695 25 to 50%

03234500 Scioto 0506 1931 2014 42,479 57,702 15,223 25 to 50%

03215000 Big Sandy 0507 1940 1975 35,913 56,825 20,913 50 to 100%

03270500 Great Miami 0508 1914 2013 21,187 27,694 6,507 25 to 50%

03274000 Great Miami 0508 1928 2013 28,522 43,535 15,013 50 to 100%

03315500 Green 0511 1938 1992 72,858 97,397 24,539 25 to 50%

03325000 Wabash 0512 1924 2013 14,101 18,927 4,826 25 to 50%

03327500 Wabash 0512 1944 2013 21,486 30,947 9,461 25 to 50%

03329000 Wabash 0512 1924 2013 29,950 43,067 13,117 25 to 50%

03335500 Wabash 0512 1924 2013 58,347 82,844 24,497 25 to 50%

03336000 Wabash 0512 1940 2013 66,245 97,160 30,915 25 to 50%

03340500 Wabash 0512 1928 2013 85,691 130,399 44,708 50 to 100%

03341500 Wabash 0512 1928 2013 95,046 140,938 45,891 25 to 50%

03342000 Wabash 0512 1939 2013 102,490 159,764 57,274 50 to 100%

03343000 Wabash 0512 1930 1993 101,445 151,548 50,103 25 to 50%

03347000 White 0512 1932 2013 1,752 2,942 1,189 50 to 100%

03348000 White 0512 1933 2012 3,109 5,476 2,367 50 to 100%

03351000 White 0512 1930 2013 9,242 15,481 6,239 50 to 100%

03353000 White 0512 1905 2013 9,639 19,639 10,000 > 100%

03354000 White 0512 1931 2014 18,817 33,272 14,456 50 to 100%

03377500 Wabash 0512 1928 2013 242,686 359,139 116,453 25 to 50%
MRG&P Report No. 34 233

Station River HUC4 

Year Streamflow [m3/s] Change in Streamflow 

Min Max Min Year Max Year [m3/s] %Change 

03384500 Ohio 0514 1941 1979

1,608,53

5 3,102,104 1,493,570 50 to 100%

03611500 Ohio 0514 1929 2014 2,564,416 3,181,919 617,503 10 to 25%

03568000 Tennessee 0602 1875 2007 408,441 348,245 -60,196 -25 to -10%

03571850 Tennessee 0603 1931 1986 336,055 445,923 109,868 25 to 50%

05220500 Mississippi 0701 1931 1989 15,082 27,832 12,750 50 to 100%

05261000 Mississippi 0701 1988 1999 32,486 80,126 47,641 > 100%

05267000 Mississippi 0701 1925 2014 34,092 66,848 32,756 50 to 100%

05288500 Mississippi 0701 1932 2013 63,964 108,447 44,483 50 to 100%

05331000 Mississippi 0701 1901 2015 73,673 174,291 100,618 > 100%

05292000 Minnesota 0702 1939 2013 682 2,348 1,667 > 100%

05301000 Minnesota 0702 1943 2013 5,017 11,033 6,016 > 100%

05311000 Minnesota 0702 1910 2013 1,767 15,503 13,736 > 100%

05325000 Minnesota 0702 1905 2013 9,918 58,757 48,839 > 100%

05330000 Minnesota 0702 1935 2013 23,207 70,836 47,630 > 100%

05339500 St. Croix 0703 1924 1960 25,871 49,247 23,376 50 to 100%

05340500 St. Croix 0703 1904 2013 34,433 53,910 19,477 50 to 100%

05344500 Mississippi 0704 1929 2015 128,004 260,135 132,131 > 100%

05378500 Mississippi 0704 1929 2011 218,444 395,649 177,206 50 to 100%

05383500 Mississippi 0704 1931 1954 172,644 414,764 242,120 > 100%

05389500 Mississippi 0706 1937 2012 312,650 467,239 154,589 25 to 50%

05391000 Wisconsin 0707 1937 2013 8,098 5,351 -2,746 -50 to -25%

05401500 Wisconsin 0707 1903 1949 76,292 42,099 -34,193 -50 to -25%

05449500 Iowa 0708 1941 2014 1,512 3,616 2,104 > 100%

05451500 Iowa 0708 1915 2014 5,744 12,560 6,816 > 100%

05454500 Iowa 0708 1904 2013 12,300 26,172 13,872 > 100%

05465500 Iowa 0708 1915 2013 51,050 110,342 59,292 > 100%

05474500 Mississippi 0708 1879 2013 574,571 808,343 233,771 25 to 50%

05425500 Rock 0709 1932 2013 3,323 7,716 4,394 > 100%

05430500 Rock 0709 1915 2013 15,517 25,582 10,065 50 to 100%

05437500 Rock 0709 1904 2013 33,597 53,390 19,792 50 to 100%

05443500 Rock 0709 1915 2014 47,350 75,869 28,519 50 to 100%

05446500 Rock 0709 1940 2013 48,023 91,622 43,600 50 to 100%
MRG&P Report No. 34 234

Station River HUC4 

Year Streamflow [m3/s] Change in Streamflow 

Min Max Min Year Max Year [m3/s] %Change 

05476000 Des Moines 0710 1936 2013 1,925 5,837 3,913 > 100%

05480500 Des Moines 0710 1914 2014 9,872 24,844 14,971 > 100%

05482000 Des Moines 0710 1916 2014 15,280 39,624 24,343 > 100%

05485500 Des Moines 0710 1941 2014 34,125 68,628 34,503 > 100%

05488500 Des Moines 0710 1921 2013 30,515 86,431 55,916 > 100%

05489500 Des Moines 0710 1918 2013 35,567 90,869 55,302 > 100%

05490500 Des Moines 0710 1904 2013 37,330 93,321 55,991 > 100%

05587450 Mississippi 0711 1934 2014 871,739 1,435,799 564,060 50 to 100%

05587500 Mississippi 0711 1934 1986 806,815 1,362,921 556,106 50 to 100%

05568500 Illinois 0713 1940 2014 139,255 186,449 47,194 25 to 50%

05585500 Illinois 0713 1939 1988 192,304 263,310 71,005 25 to 50%

05586100 Illinois 0713 1939 2015 197,873 282,791 84,918 25 to 50%

07010000 Mississippi 0714 1863 2013

1,683,30

5 2,121,470 438,165 25 to 50%

07020500 Mississippi 0714 1943 2014 1,846,101 2,455,265 609,163 25 to 50%

07022000 Mississippi 0714 1934 2014

1,705,69

5 2,628,655 922,960 50 to 100%

07026000 Obion 0801 1930 1990 22,904 33,992 11,089 25 to 50%

07032000 Mississippi 0801 1934 1993

4,294,33

6 5,794,688 1,500,352 25 to 50%

07047800 St. Francis 0802 1931 2009 30,697 19,896 -10,801 -50 to -25%

07287000 Yazoo 0803 1908 1979 78,259 122,134 43,876 50 to 100%

06054500 Missouri 1003 1911 2014 61,449 45,750 -15,699 -50 to -25%

06090800 Missouri 1003 1891 2014 85,874 69,995 -15,879 -25 to -10%

06099500 Marias 1003 1903 2015 10,407 7,348 -3,059 -50 to -25%

06115000 Missouri 1004 1935 1967 68,936 111,376 42,441 50 to 100%

06120500 Musselshell 1004 1908 2012 1,911 1,143 -768 -50 to -25%

06126500 Musselshell 1004 1947 2012 2,289 1,251 -1,038 -50 to -25%

06140500 Milk 1005 1900 2013 3,005 4,740 1,735 50 to 100%

06172000 Milk 1005 1915 1986 8,035 2,401 -5,633 -100 to -50%

06307830 Tongue 1009 1974 2005 4,835 1,769 -3,066 -100 to -50%

06327500 Yellowstone 1010 1898 2013 158,132 104,038 -54,094 -50 to -25%

06329500 Yellowstone 1010 1911 2012 153,137 104,248 -48,889 -50 to -25%
MRG&P Report No. 34 235

Station River HUC4 

Year Streamflow [m3/s] Change in Streamflow 

Min Max Min Year Max Year [m3/s] %Change 

06400500 Cheyenne 1012 1915 1971 3,590 713 -2,877 -100 to -50%

06401500 Cheyenne 1012 1946 1977 1,222 31 -1,190 -100 to -50%

06338490 Missouri 1013 1970 2008 272,060 153,332 -118,727 -50 to -25%

06454000 Niobrara 1015 1956 1993 48 27 -21 -50 to -25%

06454100 Niobrara 1015 1958 1990 159 120 -39 -25 to -10%

06454500 Niobrara 1015 1947 1993 350 241 -109 -50 to -25%

06455500 Niobrara 1015 1947 1990 305 209 -96 -50 to -25%

06457500 Niobrara 1015 1930 1990 1,445 1,045 -400 -50 to -25%

06461500 Niobrara 1015 1946 2012 8,368 7,572 -796 -10 to -5%

06462000 Niobrara 1015 1953 1982 9,944 7,720 -2,224 -25 to -10%

06465000 Niobrara 1015 1928 2001 12,807 17,588 4,781 25 to 50%

06465500 Niobrara 1015 1939 2012 13,223 20,492 7,269 50 to 100%

06468170 James 1016 1969 2013 107 1,230 1,123 > 100%

06470000 James 1016 1929 2013 -119 1,969 2,088 > 100%

06470500 James 1016 1951 2013 203 3,304 3,101 > 100%

06470878 James 1016 1982 2013 1,374 5,507 4,133 > 100%

06471000 James 1016 1946 2013 239 3,538 3,299 > 100%

06472000 James 1016 1951 2013 614 4,686 4,072 > 100%

06473000 James 1016 1946 2013 296 5,411 5,115 > 100%

06475000 James 1016 1951 2013 553 5,926 5,373 > 100%

06476000 James 1016 1944 2013 763 7,749 6,986 > 100%

06477000 James 1016 1951 2013 709 9,883 9,174 > 100%

06478500 James 1016 1929 2012 968 10,618 9,650 > 100%

06479438 Big Sioux 1017 1973 2013 209 616 407 > 100%

06480000 Big Sioux 1017 1954 2013 956 4,554 3,598 > 100%

06481000 Big Sioux 1017 1949 2013 1,870 6,262 4,392 > 100%

06482020 Big Sioux 1017 1972 2013 4,014 9,328 5,314 > 100%

06485500 Big Sioux 1017 1929 2013 5,021 19,742 14,722 > 100%

06627000 North Platte 1018 1904 1969 14,823 8,873 -5,951 -50 to -25%

06636000 North Platte 1018 1914 1958 19,914 9,767 -10,147 -100 to -50%

06641000 North Platte 1018 1906 1960 20,854 11,224 -9,630 -50 to -25%

06656000 North Platte 1018 1903 1997 22,213 13,884 -8,329 -50 to -25%
MRG&P Report No. 34 236

Station River HUC4 

Year Streamflow [m3/s] Change in Streamflow 

Min Max Min Year Max Year [m3/s] %Change 

06657000 North Platte 1018 1916 2013 8,148 3,625 -4,523 -100 to -50%

06674500 North Platte 1018 1930 2013 7,582 5,472 -2,110 -50 to -25%

06696000 South Platte 1019 1930 1997 547 1,117 570 > 100%

06711565 South Platte 1019 1984 2013 3,299 1,429 -1,870 -100 to -50%

06714215 South Platte 1019 1983 2013 3,258 800 -2,458 -100 to -50%

06720500 South Platte 1019 1927 2006 2,617 5,217 2,600 50 to 100%

06754000 South Platte 1019 1902 2006 6,599 10,059 3,460 50 to 100%

06766000 Platte 1020 1940 1990 3,536 6,708 3,172 50 to 100%

06805500 Platte 1020 1954 2012 52,489 91,704 39,215 50 to 100%

06775500 Middle Loup 1021 1946 2013 3,857 5,085 1,228 25 to 50%

06793000 Loup 1021 1930 2012 4,976 9,622 4,646 50 to 100%

06794500 Loup 1021 1935 1977 12,657 5,266 -7,391 -100 to -50%

06799350 Elkhorn 1022 1973 2012 7,763 13,424 5,662 50 to 100%

06800500 Elkhorn 1022 1929 2012 7,338 20,585 13,247 > 100%

06607500 Little Sioux 1023 1943 2013 3,212 21,827 18,614 > 100%

06610000 Missouri 1023 1929 2013 276,766 379,344 102,578 25 to 50%

06807000 Missouri 1024 1930 2013 331,042 450,442 119,400 25 to 50%

06818000 Missouri 1024 1929 2013 358,087 524,878 166,791 25 to 50%

06824500 Republican 1025 1948 1993 1,111 592 -519 -50 to -25%

06828500 Republican 1025 1951 2015 1,560 230 -1,330 -100 to -50%

06829500 Republican 1025 1947 1992 1,492 -100 -1,592 > -100%

06837000 Republican 1025 1955 2013 2,200 222 -1,978 -100 to -50%

06843500 Republican 1025 1946 2012 4,040 565 -3,475 -100 to -50%

0684450

0 Republican 1025 1948 2014 3,865 577 -3,289 -100 to -50%

06849500 Republican 1025 1953 2005 3,207 773 -2,434 -100 to -50%

06853020 Republican 1025 1985 2007 2,037 706 -1,332 -100 to -50%

06853500 Republican 1025 1933 2015 7,566 818 -6,748 -100 to -50%

06854500 Republican 1025 1920 1971 7,766 4,823 -2,943 -50 to -25%

06856000 Republican 1025 1947 2013 8,348 2,735 -5,613 -100 to -50%

06856600 Republican 1025 1918 2015 11,630 5,742 -5,889 -100 to -50%

06860000 Smoky Hill 1026 1940 2014 238 -19 -257 > -100%

06861000 Smoky Hill 1026 1951 2013 428 12 -416 -100 to -50%
MRG&P Report No. 34 237

Station River HUC4 

Year Streamflow [m3/s] Change in Streamflow 

Min Max Min Year Max Year [m3/s] %Change 

06862000 Smoky Hill 1026 1954 1980 119 -19 -138 > -100%

06864050 Smoky Hill 1026 1940 2010 1,989 713 -1,276 -100 to -50%

06865500 Smoky Hill 1026 1941 2014 3,400 1,351 -2,049 -100 to -50%

06866500 Smoky Hill 1026 1924 2013 4,258 2,537 -1,721 -50 to -25%

06893000 Missouri 1030 1929 2013 439,745 628,389 188,644 25 to 50%

07086000 Arkansas 1102 1911 2006 3,471 4,457 986 25 to 50%

07099500 Arkansas 1102 1895 1974 7,996 6,010 -1,986 -25 to -10%

07133000 Arkansas 1102 1914 2015 1,720 774 -946 -100 to -50%

07138000 Arkansas 1103 1903 2015 4,017 994 -3,023 -100 to -50%

07139000 Arkansas 1103 1923 2015 1,704 453 -1,251 -100 to -50%

07139500 Arkansas 1103 1903 2001 3,327 -120 -3,447 > -100%

07140000 Arkansas 1103 1945 2008 1,960 -124 -2,084 > -100%

07140500 Arkansas 1103 1923 1939 3,681 188 -3,493 -100 to -50%

07141300 Arkansas 1103 1941 2015 3,697 -36 -3,733 > -100%

07146500 Arkansas 1103 1903 2015 13,810 23,119 9,309 50 to 100%

07154500 Cimarron 1104 1951 2015 205 23 -182 -100 to -50%

07156900 Cimarron 1104 1966 2015 784 172 -612 -100 to -50%

07157950 Cimarron 1105 1961 2012 1,573 358 -1,215 -100 to -50%

07158000 Cimarron 1105 1938 2015 3,609 1,312 -2,297 -100 to -50%

07152500 Arkansas 1106 1926 2015 38,959 69,249 30,290 50 to 100%

07170500 Verdigris 1107 1896 2015 11,531 22,975 11,444 50 to 100%

07176000 Verdigris 1107 1936 2015 31,593 52,436 20,843 50 to 100%

07183000 Neosho 1107 1896 2015 11,708 22,517 10,809 50 to 100%

07211500 Canadian 1108 1940 2015 659 347 -312 -50 to -25%

07221500 Canadian 1108 1913 2015 2,252 677 -1,575 -100 to -50%

07224500 Canadian 1108 1937 1971 1,189 -223 -1,412 > -100%

07227000 Canadian 1108 1912 2012 2,700 -352 -3,052 > -100%

07227500 Canadian 1109 1939 2015 3,006 650 -2,356 -100 to -50%

07228000 Canadian 1109 1939 2015 2,849 61 -2,788 -100 to -50%

07237500 North Canadian 1110 1939 2015 1,960 524 -1,436 -100 to -50%

07239000 North Canadian 1110 1938 2002 2,054 788 -1,265 -100 to -50%

07164500 Arkansas 1111 1926 2015 57,449 95,619 38,171 50 to 100%
MRG&P Report No. 34 238

Table H-2. Change in maximum annual daily streamflow at index stations with 

significant trends. 

Station River HUC4 

Year Streamflow [m3/s] Change in Streamflow 

Min Max Min Year Max Year [m3/s] %Change 

03016000 Allegheny 0501 1942 2013 1,311 564 -747 -100 to -50%

03025500 Allegheny 0501 1915 2013 2,179 1,295 -883 -50 to -25%

03031500 Allegheny 0501 1933 2013 2,675 1,927 -748 -50 to -25%

03036500 Allegheny 0501 1905 2013 3,682 2,075 -1,607 -50 to -25%

03049500 Allegheny 0501 1939 2013 3,628 2,298 -1,329 -50 to -25%

03075070 Monongahela 0502 1934 2013 2,495 1,892 -603 -25 to -10%

03086000 Ohio 0503 1934 2014 6,107 4,234 -1,873 -50 to -25%

03144500 Muskingum 0504 1922 2014 1,050 639 -411 -50 to -25%

03150000 Muskingum 0504 1922 2014 1,429 872 -556 -50 to -25%

03193000 Kanawha 0505 1878 2012 3,464 2,064 -1,400 -50 to -25%

03231500 Scioto 0506 1921 2014 1,219 771 -448 -50 to -25%

03234500 Scioto 0506 1931 2014 1,317 963 -354 -50 to -25%

03282000 Kentucky 0510 1926 2013 1,776 984 -792 -50 to -25%

03284000 Kentucky 0510 1908 2013 1,734 1,317 -417 -25 to -10%

03320000 Green 0511 1931 2013 1,647 1,236 -411 -25 to -10%

03325000 Wabash 0512 1924 2013 616 219 -397 -100 to -50%

03327500 Wabash 0512 1944 2013 678 299 -379 -100 to -50%

03329000 Wabash 0512 1924 2013 1,055 598 -457 -50 to -25%

03353000 White 0512 1905 2013 354 591 237 50 to 100%

03414000 Cumberland 0513 1940 1991 1,878 414 -1,464 -100 to -50%

03417500 Cumberland 0513 1923 1990 2,738 688 -2,050 -100 to -50%

03425000 Cumberland 0513 1923 1990 3,719 1,481 -2,238 -100 to -50%

03426310 Cumberland 0513 1932 2006 2,927 2,078 -849 -50 to -25%

03426500 Cumberland 0513 1932 1981 3,188 2,049 -1,139 -50 to -25%

03431500 Cumberland 0513 1893 2013 3,525 2,605 -921 -50 to -25%

03497000 Tennessee 0601 1900 1981 2,994 734 -2,260 -100 to -50%

03566000 Hiwassee 0602 1900 2013 1,056 518 -538 -100 to -50%

03568000 Tennessee 0602 1875 2007 6,664 3,009 -3,655 -100 to -50%

05261000 Mississippi 0701 1988 1999 282 643 362 > 100%

05267000 Mississippi 0701 1925 2014 343 579 236 50 to 100%

05288500 Mississippi 0701 1932 2013 730 1,014 284 25 to 50%
MRG&P Report No. 34 239

Station River HUC4 

Year Streamflow [m3/s] Change in Streamflow 

Min Max Min Year Max Year [m3/s] %Change 

05331000 Mississippi 0701 1901 2015 803 1,663 860 > 100%

05292000 Minnesota 0702 1939 2013 6 65 59 > 100%

05311000 Minnesota 0702 1910 2013 50 211 161 > 100%

05325000 Minnesota 0702 1905 2013 263 801 537 > 100%

05330000 Minnesota 0702 1935 2013 399 883 484 > 100%

05333500 St. Croix 0703 1915 2013 121 150 29 10 to 25%

05336000 St. Croix 0703 1924 2009 269 387 118 25 to 50%

05339500 St. Croix 0703 1924 1960 351 830 479 > 100%

05340500 St. Croix 0703 1904 2013 523 788 264 50 to 100%

05344500 Mississippi 0704 1929 2015 1,426 2,414 988 50 to 100%

05378500 Mississippi 0704 1929 2011 2,131 3,346 1,215 50 to 100%

05383500 Mississippi 0704 1931 1954 1,506 4,137 2,631 > 100%

05391000 Wisconsin 0707 1937 2013 57 30 -27 -50 to -25%

05401500 Wisconsin 0707 1903 1949 1,405 654 -751 -100 to -50%

05407000 Wisconsin 0707 1914 2013 1,206 921 -285 -25 to -10%

05474500 Mississippi 0708 1879 2013 4,636 5,989 1,353 25 to 50%

05425500 Rock 0709 1932 2013 52 74 22 25 to 50%

05480500 Des Moines 0710 1914 2014 228 423 194 50 to 100%

05481300 Des Moines 0710 1968 2014 358 739 381 > 100%

05587450 Mississippi 0711 1934 2014 6,992 9,641 2,648 25 to 50%

05587500 Mississippi 0711 1934 1986 6,413 9,701 3,288 50 to 100%

05543500 Illinois 0712 1920 2013 1,008 1,792 785 50 to 100%

05568500 Illinois 0713 1940 2014 1,190 1,629 439 25 to 50%

05586100 Illinois 0713 1939 2015 1,634 2,257 622 25 to 50%

05592000 Kaskaskia 0714 1909 2014 305 76 -230 -100 to -50%

05593000 Kaskaskia 0714 1909 2014 470 211 -258 -100 to -50%

07026000 Obion 0801 1930 1990 592 1,041 449 50 to 100%

07047902 St. Francis 0802 1936 1974 560 945 385 50 to 100%

07287000 Yazoo 0803 1908 1979 886 665 -221 -25 to -10%

06065500 Missouri 1003 1923 2013 383 292 -91 -25 to -10%

06066500 Missouri 1003 1946 2013 482 270 -212 -50 to -25%

06090800 Missouri 1003 1891 2014 945 445 -500 -100 to -50%
MRG&P Report No. 34 240

Station River HUC4 

Year Streamflow [m3/s] Change in Streamflow 

Min Max Min Year Max Year [m3/s] %Change 

06101500 Marias 1003 1946 2014 84 47 -37 -50 to -25%

06109500 Missouri 1004 1936 2013 796 547 -249 -50 to -25%

06120500 Musselshell 1004 1908 2012 38 23 -15 -50 to -25%

06172000 Milk 1005 1915 1986 302 69 -233 -100 to -50%

06174500 Milk 1005 1940 2012 231 118 -113 -50 to -25%

06132000 Missouri 1006 1935 2015 625 261 -364 -100 to -50%

06177000 Missouri 1006 1929 2015 744 313 -431 -100 to -50%

06185500 Missouri 1006 1942 2013 718 359 -358 -50 to -25%

06279500 Bighorn 1008 1930 2015 406 172 -234 -100 to -50%

06294500 Bighorn 1008 1946 2013 433 165 -268 -100 to -50%

06326500 Powder 1009 1939 2013 257 96 -160 -100 to -50%

06309000 Yellowstone 1010 1929 2015 1,592 1,212 -379 -25 to -10%

06329500 Yellowstone 1010 1911 2012 2,400 1,101 -1,298 -100 to -50%

06386500 Cheyenne 1012 1949 2013 74 25 -49 -100 to -50%

06395000 Cheyenne 1012 1947 2013 70 25 -45 -100 to -50%

06338490 Missouri 1013 1970 2008 1,070 577 -493 -50 to -25%

06342500 Missouri 1013 1929 2012 2,304 440 -1,864 -100 to -50%

06440000 Missouri 1014 1934 1964 4,154 1,119 -3,035 -100 to -50%

06454500 Niobrara 1015 1947 1993 4 2 -3 -100 to -50%

06457500 Niobrara 1015 1930 1990 30 8 -21 -100 to -50%

06461500 Niobrara 1015 1946 2012 53 38 -14 -50 to -25%

06462000 Niobrara 1015 1953 1982 62 44 -18 -50 to -25%

06472000 James 1016 1951 2013 12 41 29 > 100%

06473000 James 1016 1946 2013 11 50 39 > 100%

06475000 James 1016 1951 2013 18 67 49 > 100%

06476000 James 1016 1944 2013 40 98 58 > 100%

06477000 James 1016 1951 2013 34 119 85 > 100%

06478500 James 1016 1929 2012 37 161 123 > 100%

06467500 Missouri 1017 1931 1994 3,173 491 -2,682 -100 to -50%

06627000 North Platte 1018 1904 1969 283 156 -127 -50 to -25%

06636000 North Platte 1018 1914 1958 369 71 -298 -100 to -50%

06641000 North Platte 1018 1906 1960 212 146 -66 -50 to -25%
MRG&P Report No. 34 241

Station River HUC4 

Year Streamflow [m3/s] Change in Streamflow 

Min Max Min Year Max Year [m3/s] %Change 

06642000 North Platte 1018 1905 1997 206 77 -128 -100 to -50%

06652800 North Platte 1018 1958 2013 186 226 40 10 to 25%

06656000 North Platte 1018 1903 1997 245 132 -113 -50 to -25%

06657000 North Platte 1018 1916 2013 134 52 -82 -100 to -50%

06707500 South Platte 1019 1899 2006 49 28 -20 -50 to -25%

06720500 South Platte 1019 1927 2006 65 114 50 50 to 100%

06721000 South Platte 1019 1930 2013 59 124 65 > 100%

06754000 South Platte 1019 1902 2006 128 207 79 50 to 100%

06766000 Platte 1020 1940 1990 75 145 70 50 to 100%

06775500 Middle Loup 1021 1946 2013 17 19 2 10 to 25%

06794500 Loup 1021 1935 1977 500 280 -220 -50 to -25%

06800500 Elkhorn 1022 1929 2012 260 501 240 50 to 100%

06486000 Missouri 1023 1929 2013 2,916 890 -2,026 -100 to -50%

06607500 Little Sioux 1023 1943 2013 151 388 237 > 100%

06610000 Missouri 1023 1929 2013 2,935 1,518 -1,417 -50 to -25%

06824500 Republican 1025 1948 1993 33 3 -30 -100 to -50%

06828500 Republican 1025 1951 2015 51 -1 -52 > -100%

06829500 Republican 1025 1947 1992 39 -3 -41 > -100%

06837000 Republican 1025 1955 2013 50 -3 -53 > -100%

06843500 Republican 1025 1946 2012 103 -9 -111 > -100%

06844500 Republican 1025 1948 2014 100 8 -92 -100 to -50%

06849500 Republican 1025 1953 2005 48 15 -33 -100 to -50%

06853020 Republican 1025 1985 2007 109 35 -74 -100 to -50%

06853500 Republican 1025 1933 2015 251 36 -215 -100 to -50%

06854500 Republican 1025 1920 1971 257 139 -118 -50 to -25%

06856000 Republican 1025 1947 2013 264 109 -156 -100 to -50%

06860000 Smoky Hill 1026 1940 2014 34 5 -29 -100 to -50%

06861000 Smoky Hill 1026 1951 2013 77 -2 -79 > -100%

06862000 Smoky Hill 1026 1954 1980 8 -1 -9 > -100%

06864050 Smoky Hill 1026 1940 2010 188 64 -124 -100 to -50%

06865500 Smoky Hill 1026 1941 2014 85 22 -62 -100 to -50%

06926000 Osage 1029 1926 2013 2,083 1,271 -812 -50 to -25%
MRG&P Report No. 34 242

Station River HUC4 

Year Streamflow [m3/s] Change in Streamflow 

Min Max Min Year Max Year [m3/s] %Change 

07055000 White 1101 1929 1979 1,906 241 -1,665 -100 to -50%

07061000 White 1101 1938 2012 3,411 2,021 -1,390 -50 to -25%

07074500 White 1101 1928 2013 3,100 1,840 -1,260 -50 to -25%

07086000 Arkansas 1102 1911 2006 47 63 16 25 to 50%

07099500 Arkansas 1102 1895 1974 137 87 -50 -50 to -25%

07123000 Arkansas 1102 1913 2006 152 67 -85 -100 to -50%

07124000 Arkansas 1102 1940 2015 100 36 -64 -100 to -50%

07133000 Arkansas 1102 1914 2015 137 -2 -138 > -100%

07138000 Arkansas 1103 1903 2015 225 -20 -245 > -100%

07139000 Arkansas 1103 1923 2015 112 -4 -116 > -100%

07139500 Arkansas 1103 1903 2001 101 -12 -113 > -100%

07140000 Arkansas 1103 1945 2008 37 1 -37 -100 to -50%

07141300 Arkansas 1103 1941 2015 143 18 -125 -100 to -50%

07146500 Arkansas 1103 1903 2015 490 836 346 50 to 100%

07154500 Cimarron 1104 1951 2015 49 12 -37 -100 to -50%

07156900 Cimarron 1104 1966 2015 26 -1 -27 > -100%

07157950 Cimarron 1105 1961 2012 98 14 -84 -100 to -50%

07158000 Cimarron 1105 1938 2015 378 53 -324 -100 to -50%

07176000 Verdigris 1107 1936 2015 1,006 585 -421 -50 to -25%

07178600 Verdigris 1107 1945 1969 1,479 604 -875 -100 to -50%

07211500 Canadian 1108 1940 2015 76 13 -63 -100 to -50%

07221500 Canadian 1108 1913 2015 199 24 -175 -100 to -50%

07224500 Canadian 1108 1937 1971 175 -45 -220 > -100%

07227000 Canadian 1108 1912 2012 319 -60 -379 > -100%

07227500 Canadian 1109 1939 2015 343 36 -307 -100 to -50%

07228000 Canadian 1109 1939 2015 377 -64 -441 > -100%

07228500 Canadian 1109 1945 2015 512 180 -331 -100 to -50%

07231500 Canadian 1109 1906 2015 1,566 754 -812 -100 to -50%

07245000 Canadian 1109 1939 2015 2,163 514 -1,650 -100 to -50%

07237500

North 

Canadian 1110 1939 2015 138 -19 -157 > -100%

07239000

North 

Canadian 1110 1938 2002 94 -8 -101 > -100%
MRG&P Report No. 34 243

Station River HUC4 

Year Streamflow [m3/s] Change in Streamflow 

Min Max Min Year Max Year [m3/s] %Change 

07246500 Arkansas 1111 1948 1969 8,478 1,689 -6,790 -100 to -50%

07250500 Arkansas 1111 1928 1969 7,818 4,295 -3,524 -50 to -25%

07258000 Arkansas 1111 1938 2013 7,702 2,668 -5,034 -100 to -50%

07337000 Red 1114 1937 2015 2,707 1,709 -997 -50 to -25%

 
MRG&P Report No. 34 244

Table H-3. Change in winter streamflow at index stations with significant trends. 

Station River HUC4 

Year Streamflow [m3/s] Change in Streamflow 

Min Max Min Year Max Year [m3/s] %Change 

03025500 Allegheny 0501 1915 2013 29,972 40,497 10,525 25 to 50%

03031500 Allegheny 0501 1933 2013 38,522 52,061 13,539 25 to 50%

03234500 Scioto 0506 1931 2014 11,641 19,192 7,551 50 to 100%

03336000 Wabash 0512 1940 2013 16,767 29,259 12,493 50 to 100%

03342000 Wabash 0512 1939 2013 24,799 46,629 21,829 50 to 100%

03347000 White 0512 1932 2013 547 938 391 50 to 100%

03348000 White 0512 1933 2012 873 1,744 871 50 to 100%

03353000 White 0512 1905 2013 2,477 6,068 3,591 > 100%

03384500 Ohio 0514 1941 1979 500,296 1,183,225 682,929 > 100%

03611500 Ohio 0514 1929 2014 814,536 1,098,349 283,813 25 to 50%

03568000 Tennessee 0602 1875 2007 138,989 113,508 -25,481 -25 to -10%

05211000 Mississippi 0701 1884 2013 1,135 4,452 3,317 > 100%

05220500 Mississippi 0701 1931 1989 2,326 5,944 3,619 > 100%

05261000 Mississippi 0701 1988 1999 4,832 12,871 8,039 > 100%

05267000 Mississippi 0701 1925 2014 4,521 10,308 5,787 > 100%

05288500 Mississippi 0701 1932 2013 7,514 15,314 7,800 > 100%

05331000 Mississippi 0701 1901 2015 6,646 19,145 12,499 > 100%

05292000 Minnesota 0702 1939 2013 24 94 71 > 100%

05301000 Minnesota 0702 1943 2013 172 894 722 > 100%

05311000 Minnesota 0702 1910 2013 -24 1,097 1,121 > 100%

05325000 Minnesota 0702 1905 2013 85 3,805 3,721 > 100%

05330000 Minnesota 0702 1935 2013 917 5,255 4,338 > 100%

05333500 St Croix 0703 1915 2013 2,166 2,584 418 10 to 25%

05339500 St Croix 0703 1924 1960 3,556 5,684 2,128 50 to 100%

05340500 St Croix 0703 1904 2013 4,256 7,055 2,799 50 to 100%

05344500 Mississippi 0704 1929 2015 15,309 30,508 15,199 50 to 100%

05378500 Mississippi 0704 1929 2011 28,508 54,230 25,722 50 to 100%

05383500 Mississippi 0704 1931 1954 28,283 43,885 15,603 50 to 100%

05389500 Mississippi 0706 1937 2012 37,817 68,199 30,382 50 to 100%

05391000 Wisconsin 0707 1937 2013 2,177 1,794 -384 -25 to -10%

05407000 Wisconsin 0707 1914 2013 13,732 18,403 4,671 25 to 50%
MRG&P Report No. 34 245

Station River HUC4 

Year Streamflow [m3/s] Change in Streamflow 

Min Max Min Year Max Year [m3/s] %Change 

05420500 Mississippi 0708 1874 2013 56,864 82,054 25,191 25 to 50%

05449500 Iowa 0708 1941 2014 109 264 155 > 100%

05454500 Iowa 0708 1904 2013 1,810 3,527 1,717 50 to 100%

05465500 Iowa 0708 1915 2013 7,566 13,745 6,179 50 to 100%

05474500 Mississippi 0708 1879 2013 65,594 131,939 66,344 > 100%

05425500 Rock 0709 1932 2013 481 1,244 763 > 100%

05430500 Rock 0709 1915 2013 2,620 4,981 2,361 50 to 100%

05437500 Rock 0709 1904 2013 5,344 11,284 5,940 > 100%

05446500 Rock 0709 1940 2013 9,451 19,315 9,864 > 100%

05476000 Des Moines 0710 1936 2013 32 311 279 > 100%

05488500 Des Moines 0710 1921 2013 3,353 8,273 4,920 > 100%

05489500 Des Moines 0710 1918 2013 3,586 8,953 5,366 > 100%

05490500 Des Moines 0710 1904 2013 3,533 9,442 5,909 > 100%

05587450 Mississippi 0711 1934 2014 148,310 232,495 84,186 50 to 100%

05587500 Mississippi 0711 1934 1986 135,046 219,532 84,486 50 to 100%

05568500 Illinois 0713 1940 2014 30,676 45,801 15,125 25 to 50%

05592000 Kaskaskia 0714 1909 2014 1,344 3,900 2,556 > 100%

05592500 Kaskaskia 0714 1909 2014 3,053 6,546 3,493 > 100%

05593000 Kaskaskia 0714 1909 2014 2,679 9,637 6,958 > 100%

07010000 Mississippi 0714 1863 2013 217,969 368,045 150,077 50 to 100%

07020500 Mississippi 0714 1943 2014 292,422 425,139 132,717 25 to 50%

07022000 Mississippi 0714 1934 2014 269,048 460,108 191,060 50 to 100%

07032000 Mississippi 0801 1934 1993 945,742 1,676,660 730,919 50 to 100%

06090300 Missouri 1003 1957 2014 17,253 13,959 -3,294 -25 to -10%

06090800 Missouri 1003 1891 2014 9,944 16,744 6,800 50 to 100%

06101500 Marias 1003 1946 2014 602 1,479 877 > 100%

06109500 Missouri 1004 1936 2013 14,088 18,026 3,938 25 to 50%

06115000 Missouri 1004 1935 1967 9,401 20,952 11,550 > 100%

06115200 Missouri 1004 1935 2012 14,912 19,247 4,335 25 to 50%

06126500 Musselshell 1004 1947 2012 218 125 -93 -50 to -25%

06132000 Missouri 1006 1935 2015 14,414 30,062 15,648 > 100%

06177000 Missouri 1006 1929 2015 12,648 30,516 17,868 > 100%
MRG&P Report No. 34 246

Station River HUC4 

Year Streamflow [m3/s] Change in Streamflow 

Min Max Min Year Max Year [m3/s] %Change 

06274300 Bighorn 1008 1984 2013 3,504 2,130 -1,374 -50 to -25%

06294700 Bighorn 1008 1946 1980 5,361 10,541 5,180 50 to 100%

06298000 Tongue 1009 1919 2013 153 132 -20 -25 to -10%

06307500 Tongue 1009 1940 2014 490 396 -94 -25 to -10%

06307616 Tongue 1009 1980 2012 533 340 -194 -50 to -25%

06307830 Tongue 1009 1974 2005 633 269 -364 -100 to -50%

06309000 Yellowstone 1010 1929 2015 11,858 17,135 5,277 25 to 50%

06327500 Yellowstone 1010 1898 2013 11,911 14,019 2,108 10 to 25%

06329500 Yellowstone 1010 1911 2012 13,304 17,051 3,747 25 to 50%

06395000 Cheyenne 1012 1947 2013 25 55 29 > 100%

06401500 Cheyenne 1012 1946 1977 126 -25 -151 > -100%

06438500 Cheyenne 1012 1951 2012 263 840 577 > 100%

06338490 Missouri 1013 1970 2008 71,580 41,685 -29,895 -50 to -25%

06342500 Missouri 1013 1929 2012 24,804 67,158 42,354 > 100%

06350000 Cannonball 1013 1951 2015 8 16 8 50 to 100%

06354000 Cannonball 1013 1935 2012 26 71 45 > 100%

06440000 Missouri 1014 1934 1964 16,763 32,404 15,641 50 to 100%

06452000 White 1014 1929 2012 169 518 350 > 100%

06454000 Niobrara 1015 1956 1993 10 5 -5 -50 to -25%

06454100 Niobrara 1015 1958 1990 49 32 -17 -50 to -25%

06454500 Niobrara 1015 1947 1993 114 56 -58 -100 to -50%

06455500 Niobrara 1015 1947 1990 3 2 -1 -50 to -25%

06457500 Niobrara 1015 1930 1990 348 267 -81 -25 to -10%

06465000 Niobrara 1015 1928 2001 2,674 4,111 1,437 50 to 100%

06465500 Niobrara 1015 1939 2012 2,807 4,928 2,121 50 to 100%

06468170 James 1016 1969 2013 0 7 7 > 100%

06470000 James 1016 1929 2013 1 31 30 > 100%

06470500 James 1016 1951 2013 11 104 93 > 100%

06470878 James 1016 1982 2013 38 201 162 > 100%

06471000 James 1016 1946 2013 -15 147 162 > 100%

06472000 James 1016 1951 2013 8 254 247 > 100%

06473000 James 1016 1946 2013 -34 248 282 > 100%
MRG&P Report No. 34 247

Station River HUC4 

Year Streamflow [m3/s] Change in Streamflow 

Min Max Min Year Max Year [m3/s] %Change 

06475000 James 1016 1951 2013 -30 318 348 > 100%

06476000 James 1016 1944 2013 -57 403 460 > 100%

06477000 James 1016 1951 2013 -53 476 529 > 100%

06478500 James 1016 1929 2012 -43 547 590 > 100%

06467500 Missouri 1017 1931 1994 19,159 48,501 29,342 > 100%

06479438 Big Sioux 1017 1973 2013 4 17 14 > 100%

06479500 Big Sioux 1017 1946 2013 2 9 7 > 100%

06479525 Big Sioux 1017 1977 2013 23 72 49 > 100%

06480000 Big Sioux 1017 1954 2013 2 266 264 > 100%

06481000 Big Sioux 1017 1949 2013 8 382 374 > 100%

06482020 Big Sioux 1017 1972 2013 193 509 316 > 100%

06485500 Big Sioux 1017 1929 2013 177 1,715 1,538 > 100%

06620000 North Platte 1018 1916 2015 197 274 77 25 to 50%

06630000 North Platte 1018 1940 2013 726 1,013 287 25 to 50%

06641000 North Platte 1018 1906 1960 521 -16 -538 > -100%

06642000 North Platte 1018 1905 1997 -938 2,387 3,325 > 100%

06652000 North Platte 1018 1959 2013 2,868 1,511 -1,357 -50 to -25%

06656000 North Platte 1018 1903 1997 1,033 -194 -1,227 > -100%

06657000 North Platte 1018 1916 2013 301 -74 -375 > -100%

06674500 North Platte 1018 1930 2013 1,203 348 -855 -100 to -50%

06679500 North Platte 1018 1931 1997 1,709 1,143 -566 -50 to -25%

06682000 North Platte 1018 1924 1990 2,837 1,664 -1,172 -50 to -25%

06684500 North Platte 1018 1931 1990 3,112 2,470 -642 -25 to -10%

06686000 North Platte 1018 1932 1997 3,496 2,602 -894 -50 to -25%

06690500 North Platte 1018 1943 1991 23 4 -19 -100 to -50%

06696000 South Platte 1019 1930 1997 1 139 138 > 100%

06701500 South Platte 1019 1925 2006 47 237 190 > 100%

06707500 South Platte 1019 1899 2006 194 448 253 > 100%

06711565 South Platte 1019 1984 2013 232 138 -94 -50 to -25%

06714215 South Platte 1019 1983 2013 263 5 -258 -100 to -50%

06720500 South Platte 1019 1927 2006 168 847 678 > 100%

06754000 South Platte 1019 1902 2006 1,305 1,969 665 50 to 100%
MRG&P Report No. 34 248

Station River HUC4 

Year Streamflow [m3/s] Change in Streamflow 

Min Max Min Year Max Year [m3/s] %Change 

06758500 South Platte 1019 1953 2006 793 1,740 947 > 100%

06765000 South Platte 1019 1940 1969 576 -99 -676 > -100%

06805500 Platte 1020 1954 2012 9,791 19,802 10,011 > 100%

06775500 Middle Loup 1021 1946 2013 962 1,222 260 25 to 50%

06793000 Loup 1021 1930 2012 1,249 4,253 3,005 > 100%

06797500 Elkhorn 1022 1948 2013 151 276 124 50 to 100%

06799000 Elkhorn 1022 1946 2013 720 1,067 347 25 to 50%

06799350 Elkhorn 1022 1973 2012 1,372 2,365 993 50 to 100%

06800500 Elkhorn 1022 1929 2012 840 3,351 2,511 > 100%

06486000 Missouri 1023 1929 2013 23,952 55,317 31,366 > 100%

06607500 Little Sioux 1023 1943 2013 109 2,517 2,408 > 100%

06610000 Missouri 1023 1929 2013 21,959 64,230 42,270 > 100%

06807000 Missouri 1024 1930 2013 32,120 78,906 46,787 > 100%

06813500 Missouri 1024 1950 2014 47,464 83,656 36,191 50 to 100%

06818000 Missouri 1024 1929 2013 35,009 89,135 54,126 > 100%

06824500 Republican 1025 1948 1993 290 200 -90 -50 to -25%

06828500 Republican 1025 1951 2015 368 110 -259 -100 to -50%

06829500 Republican 1025 1947 1992 258 -71 -329 > -100%

06837000 Republican 1025 1955 2013 399 104 -295 -100 to -50%

06843500 Republican 1025 1946 2012 752 127 -625 -100 to -50%

06844500 Republican 1025 1948 2014 745 180 -565 -100 to -50%

06849500 Republican 1025 1953 2005 105 9 -95 -100 to -50%

06853020 Republican 1025 1985 2007 368 75 -293 -100 to -50%

06853500 Republican 1025 1933 2015 1,058 191 -867 -100 to -50%

06854500 Republican 1025 1920 1971 1,376 583 -793 -100 to -50%

06856000 Republican 1025 1947 2013 1,043 424 -620 -100 to -50%

06856600 Republican 1025 1918 2015 1,435 677 -758 -100 to -50%

06860000 Smoky Hill 1026 1940 2014 16 -2 -17 > -100%

06861000 Smoky Hill 1026 1951 2013 22 4 -18 -100 to -50%

06862000 Smoky Hill 1026 1954 1980 7 -1 -8 > -100%

06887500 Kansas 1027 1920 2013 3,949 7,303 3,353 50 to 100%

06889000 Kansas 1027 1919 2015 4,495 7,837 3,342 50 to 100%
MRG&P Report No. 34 249

Station River HUC4 

Year Streamflow [m3/s] Change in Streamflow 

Min Max Min Year Max Year [m3/s] %Change 

06892350 Kansas 1027 1918 2013 5,394 10,681 5,287 50 to 100%

06893000 Missouri 1030 1929 2013 44,176 103,172 58,996 > 100%

06895500 Missouri 1030 1929 2013 44,517 108,475 63,958 > 100%

06909000 Missouri 1030 1926 2013 59,434 123,245 63,811 > 100%

06934500 Missouri 1030 1929 2013 87,139 175,234 88,095 > 100%

07081200 Arkansas 1102 1968 2015 35 46 11 25 to 50%

07086000 Arkansas 1102 1911 2006 129 381 252 > 100%

07093700 Arkansas 1102 1962 2006 757 1,081 323 25 to 50%

07096000 Arkansas 1102 1890 2012 788 1,014 226 25 to 50%

07097000 Arkansas 1102 1940 2006 739 1,053 313 25 to 50%

07099500 Arkansas 1102 1895 1974 936 660 -275 -50 to -25%

07109500 Arkansas 1102 1940 2015 1,247 767 -480 -50 to -25%

07123000 Arkansas 1102 1913 2006 108 290 182 > 100%

07124000 Arkansas 1102 1940 2015 164 378 214 > 100%

07130500 Arkansas 1102 1939 2015 17 4 -13 -100 to -50%

07133000 Arkansas 1102 1914 2015 180 9 -171 -100 to -50%

07138000 Arkansas 1103 1903 2015 413 256 -157 -50 to -25%

07139500 Arkansas 1103 1903 2001 503 164 -339 -100 to -50%

07140000 Arkansas 1103 1945 2008 519 -84 -603 > -100%

07141300 Arkansas 1103 1941 2015 597 -73 -669 > -100%

07146500 Arkansas 1103 1903 2015 1,508 3,092 1,585 > 100%

07154500 Cimarron 1104 1951 2015 6 2 -4 -100 to -50%

07156900 Cimarron 1104 1966 2015 198 53 -145 -100 to -50%

07157950 Cimarron 1105 1961 2012 305 114 -191 -100 to -50%

07160000 Cimarron 1105 1938 2015 528 1,878 1,350 > 100%

07161000 Cimarron 1105 1940 1989 562 1,545 983 > 100%

07152500 Arkansas 1106 1926 2015 3,490 8,914 5,424 > 100%

07224500 Canadian 1108 1937 1971 37 2 -34 -100 to -50%

07227000 Canadian 1108 1912 2012 51 -1 -52 > -100%

07228500 Canadian 1109 1945 2015 266 652 385 > 100%

07242000 North Canadian 1110 1938 2015 579 1,701 1,121 > 100%

07164500 Arkansas 1111 1926 2015 5,225 11,473 6,248 > 100%
MRG&P Report No. 34 250

Table H-4. Change in spring streamflow at index stations with significant trends. 

Station River HUC4 

Year Streamflow [m3/s] Change in Streamflow 

Min Max Min Year Max Year [m3/s] %Change 

03016000 Allegheny 0501 1942 2013 32,666 18,793 -13,873 -50 to -25%

03025500 Allegheny 0501 1915 2013 48,445 39,093 -9,352 -25 to -10%

03031500 Allegheny 0501 1933 2013 64,243 48,259 -15,984 -25 to -10%

03036500 Allegheny 0501 1905 2013 75,670 57,747 -17,923 -25 to -10%

03049500 Allegheny 0501 1939 2013 95,956 66,832 -29,124 -50 to -25%

03274000 Great Miami 0508 1928 2013 11,889 16,584 4,695 25 to 50%

03351000 White 0512 1930 2013 4,041 5,709 1,669 25 to 50%

03497000 Tennessee 0601 1900 1981 53,929 22,900 -31,029 -100 to -50%

03566000 Hiwassee 0602 1900 2013 19,933 9,008 -10,925 -100 to -50%

03568000 Tennessee 0602 1875 2007 159,774 66,213 -93,562 -100 to -50%

03589500 Tennessee 0603 1895 2002 210,867 129,398 -81,469 -50 to -25%

03609500 Tennessee 0604 1890 1983 277,932 191,014 -86,918 -50 to -25%

05211000 Mississippi 0701 1884 2013 1,694 3,654 1,960 > 100%

05220500 Mississippi 0701 1931 1989 5,359 8,764 3,405 50 to 100%

05267000 Mississippi 0701 1925 2014 12,803 24,868 12,066 50 to 100%

05288500 Mississippi 0701 1932 2013 26,377 41,829 15,452 50 to 100%

05331000 Mississippi 0701 1901 2015 30,198 72,671 42,473 > 100%

05311000 Minnesota 0702 1910 2013 1,041 7,781 6,740 > 100%

05325000 Minnesota 0702 1905 2013 5,949 26,970 21,021 > 100%

05330000 Minnesota 0702 1935 2013 12,220 31,793 19,574 > 100%

05339500 St. Croix 0703 1924 1960 11,973 19,338 7,365 50 to 100%

05340500 St. Croix 0703 1904 2013 14,731 22,405 7,675 50 to 100%

05344500 Mississippi 0704 1929 2015 57,386 99,884 42,498 50 to 100%

05378500 Mississippi 0704 1929 2011 92,619 151,686 59,067 50 to 100%

05383500 Mississippi 0704 1931 1954 69,177 173,199 104,022 > 100%

05356000 Chippewa 0705 1913 2014 1,278 1,795 517 25 to 50%

05389500 Mississippi 0706 1937 2012 129,050 178,699 49,649 25 to 50%

05391000 Wisconsin 0707 1937 2013 1,724 1,183 -541 -50 to -25%

05400760 Wisconsin 0707 1915 2014 23,083 18,006 -5,077 -25 to -10%

05401500 Wisconsin 0707 1903 1949 30,172 17,539 -12,633 -50 to -25%

05449500 Iowa 0708 1941 2014 687 1,547 860 > 100%
MRG&P Report No. 34 251

Station River HUC4 

Year Streamflow [m3/s] Change in Streamflow 

Min Max Min Year Max Year [m3/s] %Change 

05451500 Iowa 0708 1915 2014 2,559 5,334 2,774 > 100%

05454500 Iowa 0708 1904 2013 5,414 10,242 4,828 50 to 100%

05465500 Iowa 0708 1915 2013 21,985 43,422 21,437 50 to 100%

05474500 Mississippi 0708 1879 2013 225,573 317,114 91,541 25 to 50%

05425500 Rock 0709 1932 2013 1,934 3,556 1,622 50 to 100%

05430500 Rock 0709 1915 2013 7,486 10,177 2,691 25 to 50%

05443500 Rock 0709 1915 2014 19,334 27,416 8,082 25 to 50%

05446500 Rock 0709 1940 2013 20,934 32,208 11,274 50 to 100%

05476000 Des Moines 0710 1936 2013 1,151 2,713 1,562 > 100%

05480500 Des Moines 0710 1914 2014 4,926 10,968 6,043 > 100%

05482000 Des Moines 0710 1916 2014 7,582 16,431 8,849 > 100%

05488500 Des Moines 0710 1921 2013 13,479 34,315 20,836 > 100%

05489500 Des Moines 0710 1918 2013 15,887 36,154 20,268 > 100%

05490500 Des Moines 0710 1904 2013 17,708 36,584 18,875 > 100%

05587450 Mississippi 0711 1934 2014 366,122 537,750 171,628 25 to 50%

05587500 Mississippi 0711 1934 1986 333,729 539,466 205,737 50 to 100%

07010000 Mississippi 0714 1863 2013 596,455 783,715 187,261 25 to 50%

07022000 Mississippi 0714 1934 2014 644,099 935,470 291,371 25 to 50%

07047800 St. Francis 0802 1931 2009 12,232 6,074 -6,158 -100 to -50%

07288955 Yazoo 0803 1996 2012 73,397 28,936 -44,461 -100 to -50%

07291000 Homochitto 0806 1939 2015 1,136 720 -416 -50 to -25%

06090800 Missouri 1003 1891 2014 27,983 19,621 -8,362 -50 to -25%

06099500 Marias 1003 1903 2015 4,390 3,079 -1,312 -50 to -25%

06101500 Marias 1003 1946 2014 2,684 1,345 -1,339 -50 to -25%

06120500 Musselshell 1004 1908 2012 811 312 -499 -100 to -50%

06126500 Musselshell 1004 1947 2012 799 279 -520 -100 to -50%

06172000 Milk 1005 1915 1986 4,525 1,131 -3,394 -100 to -50%

06174500 Milk 1005 1940 2012 4,286 2,007 -2,279 -100 to -50%

06186500 Yellowstone 1007 1927 2015 1,647 2,095 448 25 to 50%

06191500 Yellowstone 1007 1890 2014 5,990 8,737 2,748 25 to 50%

06192500 Yellowstone 1007 1898 2013 7,624 9,869 2,245 25 to 50%

06279500 BIGHORN 1008 1930 2015 6,618 4,648 -1,970 -50 to -25%
MRG&P Report No. 34 252

Station River HUC4 

Year Streamflow [m3/s] Change in Streamflow 

Min Max Min Year Max Year [m3/s] %Change 

06294500 Bighorn 1008 1946 2013 11,221 7,545 -3,675 -50 to -25%

06307830 Tongue 1009 1974 2005 1,364 501 -863 -100 to -50%

06329500 Yellowstone 1010 1911 2012 38,659 27,847 -10,813 -50 to -25%

06401500 Cheyenne 1012 1946 1977 281 22 -260 -100 to -50%

06338490 Missouri 1013 1970 2008 62,530 35,999 -26,531 -50 to -25%

06342500 Missouri 1013 1929 2012 66,129 49,493 -16,636 -50 to -25%

06454000 Niobrara 1015 1956 1993 16 10 -7 -50 to -25%

06454500 Niobrara 1015 1947 1993 124 97 -27 -25 to -10%

06455500 Niobrara 1015 1947 1990 5 2 -3 -100 to -50%

06457500 Niobrara 1015 1930 1990 450 316 -133 -50 to -25%

06462000 Niobrara 1015 1953 1982 3,012 2,293 -719 -25 to -10%

06465000 Niobrara 1015 1928 2001 4,258 6,082 1,824 25 to 50%

06470000 James 1016 1929 2013 132 658 526 > 100%

06470500 James 1016 1951 2013 255 1,281 1,026 > 100%

06471000 James 1016 1946 2013 398 1,252 853 > 100%

06472000 James 1016 1951 2013 380 1,367 987 > 100%

06473000 James 1016 1946 2013 439 1,992 1,554 > 100%

06475000 James 1016 1951 2013 565 2,331 1,767 > 100%

06477000 James 1016 1951 2013 908 3,718 2,810 > 100%

06478500 James 1016 1929 2012 1,074 4,965 3,891 > 100%

06480000 Big Sioux 1017 1954 2013 621 2,650 2,029 > 100%

06481000 Big Sioux 1017 1949 2013 1,253 3,342 2,089 > 100%

06485500 Big Sioux 1017 1929 2013 2,904 9,688 6,785 > 100%

06627000 North Platte 1018 1904 1969 5,924 3,351 -2,572 -50 to -25%

06636000 North Platte 1018 1914 1958 8,608 2,955 -5,653 -100 to -50%

06642000 North Platte 1018 1905 1997 660 3,327 2,667 > 100%

06656000 North Platte 1018 1903 1997 5,377 1,735 -3,641 -100 to -50%

06657000 North Platte 1018 1916 2013 2,014 414 -1,600 -100 to -50%

06674500 North Platte 1018 1930 2013 1,649 795 -855 -100 to -50%

06696000 South Platte 1019 1930 1997 130 232 103 50 to 100%

06701500 South Platte 1019 1925 2006 249 473 224 50 to 100%

06714215 South Platte 1019 1983 2013 1,353 156 -1,197 -100 to -50%
MRG&P Report No. 34 253

Station River HUC4 

Year Streamflow [m3/s] Change in Streamflow 

Min Max Min Year Max Year [m3/s] %Change 

06720500 South Platte 1019 1927 2006 800 1,458 658 50 to 100%

06765000 South Platte 1019 1940 1969 863 61 -802 -100 to -50%

06805500 Platte 1020 1954 2012 21,376 29,548 8,172 25 to 50%

06775500 Middle Loup 1021 1946 2013 1,046 1,365 319 25 to 50%

06794500 Loup 1021 1935 1977 5,088 1,446 -3,642 -100 to -50%

06800500 Elkhorn 1022 1929 2012 2,793 7,604 4,812 > 100%

06607500 Little Sioux 1023 1943 2013 1,575 8,755 7,180 > 100%

06824500 Republican 1025 1948 1993 368 232 -136 -50 to -25%

06828500 Republican 1025 1951 2015 632 114 -517 -100 to -50%

06829500 Republican 1025 1947 1992 549 -97 -645 > -100%

06837000 Republican 1025 1955 2013 556 93 -463 -100 to -50%

06843500 Republican 1025 1946 2012 1,197 133 -1,064 -100 to -50%

06844500 Republican 1025 1948 2014 1,312 268 -1,044 -100 to -50%

06849500 Republican 1025 1953 2005 550 68 -482 -100 to -50%

06853500 Republican 1025 1933 2015 2,126 421 -1,705 -100 to -50%

06854500 Republican 1025 1920 1971 2,720 1,185 -1,536 -100 to -50%

06856000 Republican 1025 1947 2013 2,247 1,056 -1,191 -100 to -50%

06856600 Republican 1025 1918 2015 3,155 1,918 -1,237 -50 to -25%

06857100 Republican 1025 1964 2014 2,632 1,110 -1,522 -100 to -50%

06860000 Smoky Hill 1026 1940 2014 41 -2 -43 > -100%

06861000 Smoky Hill 1026 1951 2013 69 8 -61 -100 to -50%

06862000 Smoky Hill 1026 1954 1980 9 -2 -11 > -100%

06897500 Grand 1028 1922 2013 2,244 7,886 5,642 > 100%

06902000 Grand 1028 1925 2013 9,203 25,076 15,872 > 100%

06934500 Missouri 1030 1929 2013 223,961 323,993 100,032 25 to 50%

07086000 Arkansas 1102 1911 2006 762 1,038 277 25 to 50%

07096000 Arkansas 1102 1890 2012 1,771 1,359 -412 -25 to -10%

07099500 Arkansas 1102 1895 1974 1,733 1,095 -638 -50 to -25%

07124000 Arkansas 1102 1940 2015 197 395 198 > 100%

07138000 Arkansas 1103 1903 2015 706 307 -399 -100 to -50%

07139500 Arkansas 1103 1903 2001 574 169 -405 -100 to -50%

07140000 Arkansas 1103 1945 2008 539 -39 -579 > -100%
MRG&P Report No. 34 254

Station River HUC4 

Year Streamflow [m3/s] Change in Streamflow 

Min Max Min Year Max Year [m3/s] %Change 

07141300 Arkansas 1103 1941 2015 808 50 -758 -100 to -50%

07146500 Arkansas 1103 1903 2015 3,566 7,762 4,197 > 100%

07154500 Cimarron 1104 1951 2015 12 3 -9 -100 to -50%

07156900 Cimarron 1104 1966 2015 201 67 -133 -100 to -50%

07158000 Cimarron 1105 1938 2015 1,184 546 -638 -100 to -50%

07152500 Arkansas 1106 1926 2015 13,129 24,360 11,232 50 to 100%

07183000 Neosho 1107 1896 2015 4,170 7,637 3,468 50 to 100%

07183500 Neosho 1107 1922 2015 6,617 12,028 5,411 50 to 100%

07224500 Canadian 1108 1937 1971 62 -3 -64 > -100%

07227000 Canadian 1108 1912 2012 256 -33 -288 > -100%

07227500 Canadian 1109 1939 2015 501 60 -440 -100 to -50%

07239000 North Canadian 1110 1938 2002 697 182 -515 -100 to -50%

 
MRG&P Report No. 34 255

Table H-5. Change in summer streamflow at index stations with significant trends. 

Station River HUC4 

Year Streamflow [m3/s] Change in Streamflow 

Min Max Min Year Max Year [m3/s] %Change 

Station River HUC4 Min Max Min Year Max Year [m3/s] %Change

03025500 Allegheny 0501 1915 2013 9,804 15,370 5,566 50 to 100%

03031500 Allegheny 0501 1933 2013 13,605 21,038 7,432 50 to 100%

03036500 Allegheny 0501 1905 2013 15,148 22,985 7,837 50 to 100%

03151000 Ohio 0503 1941 1967 81,657 36,519 -45,138 -100 to -50%

03150000 Muskingum 0504 1922 2014 9,115 15,350 6,234 50 to 100%

03221000 Scioto 0506 1922 2013 718 1,545 827 > 100%

03227500 Scioto 0506 1921 2013 1,179 3,171 1,993 > 100%

03231500 Scioto 0506 1921 2014 3,394 8,009 4,614 > 100%

03234500 Scioto 0506 1931 2014 5,222 9,868 4,645 50 to 100%

03271500 Great Miami 0508 1919 1994 2,584 5,232 2,648 > 100%

03274000 Great Miami 0508 1928 2013 3,967 7,504 3,536 50 to 100%

03206000 Ohio 0509 1935 1967 140,789 54,132 -86,657 -100 to -50%

03325000 Wabash 0512 1924 2013 1,524 3,048 1,524 > 100%

03329000 Wabash 0512 1924 2013 3,671 7,467 3,797 > 100%

03335500 Wabash 0512 1924 2013 7,774 15,992 8,218 > 100%

03336000 Wabash 0512 1940 2013 10,529 19,010 8,480 50 to 100%

03340500 Wabash 0512 1928 2013 13,229 25,432 12,203 50 to 100%

03341500 Wabash 0512 1928 2013 15,101 28,083 12,982 50 to 100%

03342000 Wabash 0512 1939 2013 17,773 32,390 14,616 50 to 100%

03343000 Wabash 0512 1930 1993 16,297 29,523 13,226 50 to 100%

03347000 White 0512 1932 2013 206 466 260 > 100%

03348000 White 0512 1933 2012 464 897 434 50 to 100%

03351000 White 0512 1930 2013 1,163 2,575 1,412 > 100%

03353000 White 0512 1905 2013 1,110 3,149 2,039 > 100%

03354000 White 0512 1931 2014 2,332 5,829 3,497 > 100%

03377500 Wabash 0512 1928 2013 36,466 67,712 31,245 50 to 100%

03414000 Cumberland 0513 1940 1991 9,757 23,331 13,574 > 100%

03417500 Cumberland 0513 1923 1990 8,687 29,656 20,969 > 100%

03425000 Cumberland 0513 1923 1990 15,253 35,738 20,485 > 100%

03426310 Cumberland 0513 1932 2006 21,142 38,634 17,492 50 to 100%
MRG&P Report No. 34 256

Station River HUC4 

Year Streamflow [m3/s] Change in Streamflow 

Min Max Min Year Max Year [m3/s] %Change 

03426500 Cumberland 0513 1932 1981 17,365 37,041 19,676 > 100%

03611500 Ohio 0514 1929 2014 347,915 480,738 132,823 25 to 50%

03497000 Tennessee 0601 1900 1981 22,502 35,065 12,563 50 to 100%

03568000 Tennessee 0602 1875 2007 61,965 78,883 16,918 25 to 50%

03571850 Tennessee 0603 1931 1986 48,871 101,993 53,122 > 100%

03575500 Tennessee 0603 1925 1994 63,969 91,662 27,693 25 to 50%

03589500 Tennessee 0603 1895 2002 74,831 97,792 22,962 25 to 50%

03593500 Tennessee 0604 1931 2004 78,801 109,967 31,166 25 to 50%

03609500 Tennessee 0604 1890 1983 87,185 111,884 24,699 25 to 50%

05220500 Mississippi 0701 1931 1989 3,571 6,877 3,306 50 to 100%

05261000 Mississippi 0701 1988 1999 6,603 19,657 13,053 > 100%

05267000 Mississippi 0701 1925 2014 8,341 18,111 9,770 > 100%

05288500 Mississippi 0701 1932 2013 15,759 30,208 14,449 50 to 100%

05331000 Mississippi 0701 1901 2015 21,373 49,936 28,564 > 100%

05311000 Minnesota 0702 1910 2013 618 4,235 3,617 > 100%

05325000 Minnesota 0702 1905 2013 3,144 17,980 14,837 > 100%

05330000 Minnesota 0702 1935 2013 6,616 22,311 15,695 > 100%

05339500 St. Croix 0703 1924 1960 4,810 13,627 8,817 > 100%

05340500 St. Croix 0703 1904 2013 8,066 12,746 4,680 50 to 100%

05344500 Mississippi 0704 1929 2015 30,231 76,086 45,855 > 100%

05378500 Mississippi 0704 1929 2011 56,442 104,002 47,560 50 to 100%

05383500 Mississippi 0704 1931 1954 34,789 125,894 91,105 > 100%

05389500 Mississippi 0706 1937 2012 82,544 126,923 44,380 50 to 100%

05391000 Wisconsin 0707 1937 2013 2,132 1,128 -1,004 -50 to -25%

05401500 Wisconsin 0707 1903 1949 17,925 9,263 -8,662 -50 to -25%

05449500 Iowa 0708 1941 2014 441 1,193 752 > 100%

05451500 Iowa 0708 1915 2014 1,254 4,332 3,078 > 100%

05453100 Iowa 0708 1957 2014 3,685 9,069 5,384 > 100%

05454500 Iowa 0708 1904 2013 2,373 9,111 6,739 > 100%

05455700 Iowa 0708 1957 2013 6,240 13,083 6,844 > 100%

05465500 Iowa 0708 1915 2013 10,818 35,257 24,439 > 100%

05425500 Rock 0709 1932 2013 484 1,461 977 > 100%
MRG&P Report No. 34 257

Station River HUC4 

Year Streamflow [m3/s] Change in Streamflow 

Min Max Min Year Max Year [m3/s] %Change 

05427570 Rock 0709 1976 2010 2,204 5,747 3,542 > 100%

05430500 Rock 0709 1915 2013 2,568 5,131 2,563 50 to 100%

05437500 Rock 0709 1904 2013 6,063 12,226 6,163 > 100%

05443500 Rock 0709 1915 2014 7,501 19,406 11,905 > 100%

05446500 Rock 0709 1940 2013 9,120 22,745 13,624 > 100%

05476000 Des Moines 0710 1936 2013 527 1,964 1,436 > 100%

05476750 Des Moines 0710 1965 2014 1,724 5,234 3,510 > 100%

05480500 Des Moines 0710 1914 2014 2,769 8,610 5,841 > 100%

05481300 Des Moines 0710 1968 2014 6,303 14,115 7,812 > 100%

05481500 Des Moines 0710 1921 1967 2,990 6,624 3,634 > 100%

05482000 Des Moines 0710 1916 2014 3,808 16,062 12,254 > 100%

05485500 Des Moines 0710 1941 2014 10,844 25,211 14,367 > 100%

05488500 Des Moines 0710 1921 2013 6,503 34,725 28,221 > 100%

05489500 Des Moines 0710 1918 2013 8,494 35,305 26,811 > 100%

05490500 Des Moines 0710 1904 2013 8,333 35,563 27,229 > 100%

05587450 Mississippi 0711 1934 2014 213,238 407,536 194,298 50 to 100%

05568500 Illinois 0713 1940 2014 29,607 43,029 13,422 25 to 50%

05586100 Illinois 0713 1939 2015 43,784 70,487 26,704 50 to 100%

07022000 Mississippi 0714 1934 2014 468,886 726,904 258,019 50 to 100%

07026000 Obion 0801 1930 1990 2,585 4,632 2,047 50 to 100%

07287000 Yazoo 0803 1908 1979 9,035 26,339 17,304 > 100%

07360000 Ouachita 0804 1930 1976 1,234 6,256 5,022 > 100%

07362000 Ouachita 0804 1929 2015 3,915 14,690 10,775 > 100%

06054500 Missouri 1003 1911 2014 21,801 13,840 -7,961 -50 to -25%

06090800 Missouri 1003 1891 2014 34,054 20,158 -13,896 -50 to -25%

06099500 Marias 1003 1903 2015 3,940 2,680 -1,260 -50 to -25%

06140500 Milk 1005 1900 2013 862 2,859 1,997 > 100%

06279500 Bighorn 1008 1930 2015 10,749 6,352 -4,398 -50 to -25%

06294500 Bighorn 1008 1946 2013 15,031 9,621 -5,410 -50 to -25%

06327500 Yellowstone 1010 1898 2013 89,546 46,383 -43,163 -50 to -25%

06329500 Yellowstone 1010 1911 2012 77,729 42,075 -35,655 -50 to -25%

06386500 Cheyenne 1012 1949 2013 382 48 -334 -100 to -50%
MRG&P Report No. 34 258

Station River HUC4 

Year Streamflow [m3/s] Change in Streamflow 

Min Max Min Year Max Year [m3/s] %Change 

06395000 Cheyenne 1012 1947 2013 479 97 -383 -100 to -50%

06401500 Cheyenne 1012 1946 1977 480 96 -384 -100 to -50%

06423500 Cheyenne 1012 1929 2013 1,659 705 -954 -100 to -50%

06338490 Missouri 1013 1970 2008 70,916 44,498 -26,418 -50 to -25%

06342500 Missouri 1013 1929 2012 85,499 51,438 -34,061 -50 to -25%

06440000 Missouri 1014 1934 1964 105,406 62,552 -42,854 -50 to -25%

06446000 White 1014 1944 2013 183 98 -85 -50 to -25%

06454000 Niobrara 1015 1956 1993 10 6 -3 -50 to -25%

06457500 Niobrara 1015 1930 1990 316 221 -95 -50 to -25%

06461500 Niobrara 1015 1946 2012 1,929 1,560 -369 -25 to -10%

06462000 Niobrara 1015 1953 1982 2,257 1,528 -729 -50 to -25%

06465500 Niobrara 1015 1939 2012 2,307 4,797 2,490 > 100%

06468170 James 1016 1969 2013 4 159 155 > 100%

06470000 James 1016 1929 2013 -169 777 946 > 100%

06470500 James 1016 1951 2013 -74 1,363 1,437 > 100%

06470878 James 1016 1982 2013 134 2,462 2,328 > 100%

06471000 James 1016 1946 2013 -75 1,400 1,475 > 100%

06472000 James 1016 1951 2013 130 2,374 2,244 > 100%

06473000 James 1016 1946 2013 51 2,172 2,121 > 100%

06475000 James 1016 1951 2013 58 2,337 2,279 > 100%

06476000 James 1016 1944 2013 126 2,764 2,638 > 100%

06477000 James 1016 1951 2013 14 3,350 3,337 > 100%

06478500 James 1016 1929 2012 88 3,573 3,485 > 100%

06467500 Missouri 1017 1931 1994 101,955 77,985 -23,970 -25 to -10%

06480000 Big Sioux 1017 1954 2013 209 1,322 1,113 > 100%

06481000 Big Sioux 1017 1949 2013 434 1,703 1,268 > 100%

06482020 Big Sioux 1017 1972 2013 949 2,433 1,484 > 100%

06485500 Big Sioux 1017 1929 2013 1,297 5,678 4,382 > 100%

06627000 North Platte 1018 1904 1969 6,887 3,838 -3,049 -50 to -25%

06636000 North Platte 1018 1914 1958 9,641 2,386 -7,255 -100 to -50%

06641000 North Platte 1018 1906 1960 13,284 8,563 -4,722 -50 to -25%

06642000 North Platte 1018 1905 1997 11,262 4,830 -6,431 -100 to -50%
MRG&P Report No. 34 259

Station River HUC4 

Year Streamflow [m3/s] Change in Streamflow 

Min Max Min Year Max Year [m3/s] %Change 

06690500 North Platte 1018 1943 1991 2,277 3,358 1,081 25 to 50%

06691000 North Platte 1018 1937 1990 1,219 2,855 1,636 > 100%

06714215 South Platte 1019 1983 2013 1,155 427 -728 -100 to -50%

06720500 South Platte 1019 1927 2006 1,266 1,927 661 50 to 100%

06754000 South Platte 1019 1902 2006 1,922 2,966 1,043 50 to 100%

06766000 Platte 1020 1940 1990 1,273 3,193 1,920 > 100%

06775500 Middle Loup 1021 1946 2013 908 1,264 356 25 to 50%

06794500 Loup 1021 1935 1977 3,343 414 -2,929 -100 to -50%

06799350 Elkhorn 1022 1973 2012 1,565 4,068 2,503 > 100%

06800500 Elkhorn 1022 1929 2012 2,335 5,897 3,562 > 100%

06607500 Little Sioux 1023 1943 2013 980 7,084 6,104 > 100%

06828500 Republican 1025 1951 2015 297 3 -294 -100 to -50%

06829500 Republican 1025 1947 1992 462 117 -345 -100 to -50%

06837000 Republican 1025 1955 2013 640 75 -565 -100 to -50%

06843500 Republican 1025 1946 2012 1,221 328 -893 -100 to -50%

06844500 Republican 1025 1948 2014 927 128 -798 -100 to -50%

06849500 Republican 1025 1953 2005 1,622 679 -943 -100 to -50%

06853020 Republican 1025 1985 2007 591 148 -443 -100 to -50%

06853500 Republican 1025 1933 2015 2,827 42 -2,785 -100 to -50%

06856000 Republican 1025 1947 2013 2,987 864 -2,124 -100 to -50%

06856600 Republican 1025 1918 2015 4,470 1,992 -2,479 -100 to -50%

06860000 Smoky Hill 1026 1940 2014 106 0.17 -106 -100 to -50%

06861000 Smoky Hill 1026 1951 2013 226 0.17 -225 -100 to -50%

06862000 Smoky Hill 1026 1954 1980 43 -5 -49 > -100%

06864050 Smoky Hill 1026 1940 2010 847 256 -591 -100 to -50%

06864500 Smoky Hill 1026 1896 2014 1,087 632 -455 -50 to -25%

06865500 Smoky Hill 1026 1941 2014 1,310 612 -698 -100 to -50%

07055000 White 1101 1929 1979 7,770 17,000 9,230 > 100%

07060500 White 1101 1940 2015 16,617 29,451 12,834 50 to 100%

07061000 White 1101 1938 2012 19,011 31,185 12,174 50 to 100%

07138000 Arkansas 1103 1903 2015 1,549 446 -1,103 -100 to -50%

07139000 Arkansas 1103 1923 2015 636 159 -477 -100 to -50%
MRG&P Report No. 34 260

Station River HUC4 

Year Streamflow [m3/s] Change in Streamflow 

Min Max Min Year Max Year [m3/s] %Change 

07139500 Arkansas 1103 1903 2001 1,212 -168 -1,381 > -100%

07140000 Arkansas 1103 1945 2008 403 -11 -414 > -100%

07141300 Arkansas 1103 1941 2015 1,266 54 -1,212 -100 to -50%

07154500 Cimarron 1104 1951 2015 133 11 -122 -100 to -50%

07156900 Cimarron 1104 1966 2015 172 34 -139 -100 to -50%

07157950 Cimarron 1105 1961 2012 455 33 -422 -100 to -50%

07158000 Cimarron 1105 1938 2015 1,165 278 -887 -100 to -50%

07176000 Verdigris 1107 1936 2015 6,496 15,035 8,539 > 100%

07183000 Neosho 1107 1896 2015 2,967 8,078 5,111 > 100%

07211500 Canadian 1108 1940 2015 311 112 -199 -100 to -50%

07221500 Canadian 1108 1913 2015 1,136 225 -911 -100 to -50%

07224500 Canadian 1108 1937 1971 564 -114 -678 > -100%

07227000 Canadian 1108 1912 2012 1,458 -211 -1,669 > -100%

07227500 Canadian 1109 1939 2015 1,585 265 -1,320 -100 to -50%

07228000 Canadian 1109 1939 2015 1,161 -183 -1,345 > -100%

07237500 North Canadian 1110 1939 2015 708 65 -643 -100 to -50%

07239000 North Canadian 1110 1938 2002 706 220 -486 -100 to -50%

 
MRG&P Report No. 34 261

Table H-6. Change in fall streamflow at index stations with significant trends. 

Station River HUC4 

Year Streamflow [m3/s] Change in Streamflow 

Min Max Min Year Max Year [m3/s] %Change 

03016000 Allegheny 0501 1942 2013 7,467 14,356 6,890 50 to 100%

03025500 Allegheny 0501 1915 2013 10,772 20,884 10,112 50 to 100%

03031500 Allegheny 0501 1933 2013 11,641 28,197 16,555 > 100%

03049500 Allegheny 0501 1939 2013 18,404 37,846 19,442 > 100%

03086000 Ohio 0503 1934 2014 31,637 58,057 26,420 50 to 100%

03140500 Muskingum 0504 1937 2014 3,477 7,034 3,557 > 100%

03144500 Muskingum 0504 1922 2014 3,966 8,326 4,359 > 100%

03150000 Muskingum 0504 1922 2014 4,681 10,334 5,653 > 100%

03221000 Scioto 0506 1922 2013 230 838 608 > 100%

03227500 Scioto 0506 1921 2013 474 1,811 1,337 > 100%

03231500 Scioto 0506 1921 2014 1,386 4,553 3,167 > 100%

03234500 Scioto 0506 1931 2014 1,892 6,027 4,135 > 100%

03204000 Guyandotte 0507 1916 1994 321 1,628 1,307 > 100%

03215000 Big Sandy 0507 1940 1975 1,078 4,998 3,920 > 100%

03274000 Great Miami 0508 1928 2013 2,030 4,455 2,425 > 100%

03253500 Licking 0510 1916 2013 1,076 4,396 3,320 > 100%

03282000 Kentucky 0510 1926 2013 2,139 3,865 1,726 50 to 100%

03287000 Kentucky 0510 1926 2013 3,437 6,980 3,543 > 100%

03315500 Green 0511 1938 1992 2,608 15,156 12,549 > 100%

03316500 Green 0511 1940 2013 5,533 14,226 8,693 > 100%

03320000 Green 0511 1931 2013 4,917 18,053 13,136 > 100%

03325000 Wabash 0512 1924 2013 765 2,436 1,671 > 100%

03327500 Wabash 0512 1944 2013 1,470 4,396 2,926 > 100%

03329000 Wabash 0512 1924 2013 2,189 5,343 3,154 > 100%

03335500 Wabash 0512 1924 2013 5,531 9,577 4,046 50 to 100%

03336000 Wabash 0512 1940 2013 6,560 11,195 4,635 50 to 100%

03340500 Wabash 0512 1928 2013 7,458 13,584 6,125 50 to 100%

03341500 Wabash 0512 1928 2013 8,506 14,723 6,217 50 to 100%

03342000 Wabash 0512 1939 2013 9,498 16,649 7,151 50 to 100%

03343000 Wabash 0512 1930 1993 8,040 18,615 10,575 > 100%

03347000 White 0512 1932 2013 111 296 185 > 100%
MRG&P Report No. 34 262

Station River HUC4 

Year Streamflow [m3/s] Change in Streamflow 

Min Max Min Year Max Year [m3/s] %Change 

03348000 White 0512 1933 2012 266 521 255 50 to 100%

03351000 White 0512 1930 2013 733 1,504 771 > 100%

03353000 White 0512 1905 2013 694 1,798 1,104 > 100%

03354000 White 0512 1931 2014 1,628 3,479 1,851 > 100%

03377500 Wabash 0512 1928 2013 19,298 36,773 17,475 50 to 100%

03414000 Cumberland 0513 1940 1991 6,618 15,377 8,758 > 100%

03417500 Cumberland 0513 1923 1990 4,973 20,701 15,728 > 100%

03425000 Cumberland 0513 1923 1990 8,118 28,797 20,679 > 100%

03426310 Cumberland 0513 1932 2006 12,375 31,083 18,708 > 100%

03426500 Cumberland 0513 1932 1981 7,297 31,934 24,637 > 100%

03431500 Cumberland 0513 1893 2013 10,015 25,831 15,816 > 100%

03294500 Ohio 0514 1929 2013 78,093 155,708 77,615 50 to 100%

03384500 Ohio 0514 1941 1979 75,722 540,285 464,563 > 100%

03611500 Ohio 0514 1929 2014 196,232 422,056 225,823 > 100%

03497000 Tennesee 0601 1900 1981 12,244 35,296 23,052 > 100%

03566000 Hiwassee 0602 1900 2013 6,069 10,378 4,309 50 to 100%

03568000 Tennesee 0602 1875 2007 36,271 85,591 49,320 > 100%

03571850 Tennesee 0603 1931 1986 51,493 97,218 45,725 50 to 100%

03575500 Tennesee 0603 1925 1994 60,551 89,890 29,339 25 to 50%

03589500 Tennesee 0603 1895 2002 37,898 112,948 75,050 > 100%

03593500 Tennesee 0604 1931 2004 70,096 110,204 40,109 50 to 100%

03609500 Tennesee 0604 1890 1983 44,527 112,958 68,431 > 100%

05211000 Mississippi 0701 1884 2013 4,163 2,952 -1,211 -50 to -25%

05220500 Mississippi 0701 1931 1989 2,859 6,762 3,903 > 100%

05261000 Mississippi 0701 1988 1999 6,878 15,957 9,079 > 100%

05267000 Mississippi 0701 1925 2014 7,129 12,654 5,526 50 to 100%

05288500 Mississippi 0701 1932 2013 11,120 20,444 9,324 50 to 100%

05331000 Mississippi 0701 1901 2015 13,889 26,881 12,992 50 to 100%

05292000 Minnesota 0702 1939 2013 3 160 157 > 100%

05301000 Minnesota 0702 1943 2013 166 1,051 885 > 100%

05311000 Minnesota 0702 1910 2013 99 1,496 1,397 > 100%

05325000 Minnesota 0702 1905 2013 852 6,078 5,225 > 100%
MRG&P Report No. 34 263

Station River HUC4 

Year Streamflow [m3/s] Change in Streamflow 

Min Max Min Year Max Year [m3/s] %Change 

05330000 Minnesota 0702 1935 2013 2,240 8,439 6,198 > 100%

05339500 St Crois 0703 1924 1960 4,826 8,210 3,384 50 to 100%

05340500 St Crois 0703 1904 2013 5,948 10,817 4,869 50 to 100%

05344500 Mississippi 0704 1929 2015 21,155 46,673 25,518 > 100%

05378500 Mississippi 0704 1929 2011 36,326 77,096 40,770 > 100%

05383500 Mississippi 0704 1931 1954 31,492 61,236 29,744 50 to 100%

05389500 Mississippi 0706 1937 2012 58,784 88,683 29,898 50 to 100%

05391000 Wisconsin 0707 1937 2013 1,821 1,285 -536 -50 to -25%

05401500 Wisconsin 0707 1903 1949 16,564 7,412 -9,152 -100 to -50%

05425500 Rock 0709 1932 2013 327 973 646 > 100%

05430500 Rock 0709 1915 2013 2,425 4,395 1,970 50 to 100%

05437500 Rock 0709 1904 2013 4,809 9,847 5,038 > 100%

05443500 Rock 0709 1915 2014 7,653 13,189 5,536 50 to 100%

05446500 Rock 0709 1940 2013 8,392 15,432 7,040 50 to 100%

05476000 Des Moines 0710 1936 2013 144 481 336 > 100%

05587450 Mississippi 0711 1934 2014 135,252 233,282 98,030 50 to 100%

05587500 Mississippi 0711 1934 1986 103,354 249,812 146,458 > 100%

05543500 Illinois 0712 1920 2013 23,930 14,723 -9,207 -50 to -25%

05558300 Illinois 0713 1982 2013 29,868 19,504 -10,364 -50 to -25%

05568500 Illinois 0713 1940 2014 19,501 28,302 8,801 25 to 50%

05585500 Illinois 0713 1939 1988 21,719 34,884 13,166 50 to 100%

05586100 Illinois 0713 1939 2015 24,285 35,159 10,874 25 to 50%

07010000 Mississippi 0714 1863 2013 234,864 385,149 150,285 50 to 100%

07020500 Mississippi 0714 1943 2014 299,691 444,179 144,488 25 to 50%

07022000 Mississippi 0714 1934 2014 289,709 457,580 167,871 50 to 100%

07026000 Obion 0801 1930 1990 1,745 4,449 2,704 > 100%

07026040 Obion 0801 1930 2012 2,149 4,298 2,149 50 to 100%

07026300 Obion 0801 1956 1984 1,571 4,042 2,470 > 100%

07032000 Mississippi 0801 1934 1993 462,376 923,696 461,320 50 to 100%

07047902 St. Francis 0802 1936 1974 3,432 8,504 5,072 > 100%

07047970 Mississippi 0802 1929 1976 460,458 769,031 308,572 50 to 100%

07077800 White 0802 1929 1980 22,500 42,676 20,176 50 to 100%
MRG&P Report No. 34 264

Station River HUC4 

Year Streamflow [m3/s] Change in Streamflow 

Min Max Min Year Max Year [m3/s] %Change 

07265450 Mississippi 0803 1929 1979 484,687 966,747 482,060 50 to 100%

07287000 Yazoo 0803 1908 1979 -1,309 22,805 24,114 > 100%

07360000 Ouachita 0804 1930 1976 2,331 6,775 4,444 > 100%

07362000 Ouachita 0804 1929 2015 4,839 10,146 5,307 > 100%

07290000 Big Black 0806 1937 2015 1,274 3,418 2,144 > 100%

07291000 Homochitto 0806 1939 2015 183 328 145 50 to 100%

06090800 Missouri 1003 1891 2014 12,201 14,345 2,144 10 to 25%

06099500 Marias 1003 1903 2015 1,074 704 -370 -50 to -25%

06115000 Missouri 1004 1935 1967 11,298 19,604 8,306 50 to 100%

06127500 Musselshell 1004 1946 1978 104 337 233 > 100%

06132000 Missouri 1006 1935 2015 29,780 16,874 -12,906 -50 to -25%

06185500 Missouri 1006 1942 2013 35,736 14,289 -21,447 -100 to -50%

06307500 Tongue 1009 1940 2014 855 529 -325 -50 to -25%

06401500 Cheyenne 1012 1946 1977 48 -10 -58 > -100%

06423500 Cheyenne 1012 1929 2013 267 422 155 50 to 100%

06338490 Missouri 1013 1970 2008 60,256 32,391 -27,864 -50 to -25%

06446000 White 1014 1944 2013 52 27 -25 -50 to -25%

06454000 Niobrara 1015 1956 1993 8 5 -3 -50 to -25%

06455500 Niobrara 1015 1947 1990 44 4 -40 -100 to -50%

06457500 Niobrara 1015 1930 1990 299 234 -65 -25 to -10%

06461500 Niobrara 1015 1946 2012 1,997 1,440 -556 -50 to -25%

06462000 Niobrara 1015 1953 1982 2,296 1,666 -631 -50 to -25%

06465000 Niobrara 1015 1928 2001 2,818 3,595 776 25 to 50%

06465500 Niobrara 1015 1939 2012 2,917 4,101 1,185 25 to 50%

06468170 James 1016 1969 2013 -1 23 25 > 100%

06470000 James 1016 1929 2013 -50 216 267 > 100%

06470500 James 1016 1951 2013 -10 417 427 > 100%

06471000 James 1016 1946 2013 -104 676 781 > 100%

06472000 James 1016 1951 2013 -114 1,125 1,239 > 100%

06473000 James 1016 1946 2013 -225 1,110 1,336 > 100%

06475000 James 1016 1951 2013 -181 1,116 1,297 > 100%

06476000 James 1016 1944 2013 -278 1,270 1,548 > 100%
MRG&P Report No. 34 265

Station River HUC4 

Year Streamflow [m3/s] Change in Streamflow 

Min Max Min Year Max Year [m3/s] %Change 

06477000 James 1016 1951 2013 -256 1,405 1,661 > 100%

06478500 James 1016 1929 2012 -175 1,087 1,261 > 100%

06467500 Missouri 1017 1931 1994 42,504 98,736 56,231 > 100%

06479438 Big Sioux 1017 1973 2013 5 51 46 > 100%

06479500 Big Sioux 1017 1946 2013 3 26 23 > 100%

06480000 Big Sioux 1017 1954 2013 8 563 555 > 100%

06481000 Big Sioux 1017 1949 2013 36 721 685 > 100%

06485500 Big Sioux 1017 1929 2013 299 2,202 1,903 > 100%

06627000 North Platte 1018 1904 1969 1,015 745 -271 -50 to -25%

06641000 North Platte 1018 1906 1960 3,204 877 -2,327 -100 to -50%

06642000 North Platte 1018 1905 1997 723 3,152 2,429 > 100%

06652000 North Platte 1018 1959 2013 3,832 2,022 -1,811 -50 to -25%

06652800 North Platte 1018 1958 2013 2,675 1,059 -1,616 -100 to -50%

06656000 North Platte 1018 1903 1997 3,313 2,362 -951 -50 to -25%

06657000 North Platte 1018 1916 2013 922 231 -690 -100 to -50%

06674500 North Platte 1018 1930 2013 1,555 1,054 -501 -50 to -25%

06679500 North Platte 1018 1931 1997 1,457 1,795 338 10 to 25%

06696000 South Platte 1019 1930 1997 75 218 143 > 100%

06701500 South Platte 1019 1925 2006 257 438 181 50 to 100%

06707500 South Platte 1019 1899 2006 529 768 240 25 to 50%

06711565 South Platte 1019 1984 2013 342 203 -139 -50 to -25%

06720500 South Platte 1019 1927 2006 236 918 682 > 100%

06754000 South Platte 1019 1902 2006 996 2,035 1,039 > 100%

06758500 South Platte 1019 1953 2006 808 1,330 522 50 to 100%

06759500 South Platte 1019 1944 2014 517 1,028 511 50 to 100%

06805500 Platte 1020 1954 2012 8,256 17,433 9,177 > 100%

06775500 Middle Loup 1021 1946 2013 933 1,236 303 25 to 50%

06793000 Loup 1021 1930 2012 286 1,112 827 > 100%

06794500 Loup 1021 1935 1977 1,286 555 -731 -100 to -50%

06799350 Elkhorn 1022 1973 2012 946 1,947 1,001 > 100%

06800500 Elkhorn 1022 1929 2012 885 2,683 1,798 > 100%

06486000 Missouri 1023 1929 2013 62,806 93,716 30,910 25 to 50%
MRG&P Report No. 34 266

Station River HUC4 

Year Streamflow [m3/s] Change in Streamflow 

Min Max Min Year Max Year [m3/s] %Change 

06607500 Little Sioux 1023 1943 2013 453 2,397 1,944 > 100%

06610000 Missouri 1023 1929 2013 50,456 111,898 61,441 > 100%

06807000 Missouri 1024 1930 2013 61,517 122,933 61,416 50 to 100%

06818000 Missouri 1024 1929 2013 65,264 137,485 72,221 > 100%

06824500 Republican 1025 1948 1993 189 109.71 -79 -50 to -25%

06828500 Republican 1025 1951 2015 178 26.30 -152 -100 to -50%

06829500 Republican 1025 1947 1992 101 -22 -123 > -100%

06837000 Republican 1025 1955 2013 375 25 -351 -100 to -50%

06843500 Republican 1025 1946 2012 495 62 -433 -100 to -50%

06844500 Republican 1025 1948 2014 458 85 -373 -100 to -50%

06849500 Republican 1025 1953 2005 169 1.07 -168 -100 to -50%

06853020 Republican 1025 1985 2007 310 42 -268 -100 to -50%

06853500 Republican 1025 1933 2015 834 165 -669 -100 to -50%

06856000 Republican 1025 1947 2013 1,129 450 -679 -100 to -50%

06856600 Republican 1025 1918 2015 1,686 818 -868 -100 to -50%

06857100 Republican 1025 1964 2014 1,623 689 -934 -100 to -50%

06860000 Smoky Hill 1026 1940 2014 13 0.21 -13 -100 to -50%

06861000 Smoky Hill 1026 1951 2013 27 4 -23 -100 to -50%

06862000 Smoky Hill 1026 1954 1980 27 -7 -33 > -100%

06864050 Smoky Hill 1026 1940 2010 244 99 -145 -100 to -50%

06865500 Smoky Hill 1026 1941 2014 554 249 -306 -100 to -50%

06866500 Smoky Hill 1026 1924 2013 761 439 -322 -50 to -25%

06870200 Smoky Hill 1026 1963 2006 1,032 530 -501 -50 to -25%

06893000 Missouri 1030 1929 2013 81,129 157,732 76,603 50 to 100%

06895500 Missouri 1030 1929 2013 79,966 156,429 76,463 50 to 100%

06909000 Missouri 1030 1926 2013 97,070 174,698 77,628 50 to 100%

06934500 Missouri 1030 1929 2013 110,745 209,139 98,394 50 to 100%

07055000 White 1101 1929 1979 4,447 11,718 7,271 > 100%

07099500 Arkansas 1102 1895 1974 1,082 733 -349 -50 to -25%

07124000 Arkansas 1102 1940 2015 143 307 164 > 100%

07139500 Arkansas 1103 1903 2001 225 131 -94 -50 to -25%

07140000 Arkansas 1103 1945 2008 300 -26 -327 > -100%
MRG&P Report No. 34 267

Station River HUC4 

Year Streamflow [m3/s] Change in Streamflow 

Min Max Min Year Max Year [m3/s] %Change 

07141300 Arkansas 1103 1941 2015 587 -52 -639 > -100%

07156900 Cimarron 1104 1966 2015 162 38 -123 -100 to -50%

07157950 Cimarron 1105 1961 2012 323 -21 -344 > -100%

07158000 Cimarron 1105 1938 2015 545 147 -398 -100 to -50%

07211500 Canadian 1108 1940 2015 82 30 -52 -100 to -50%

07221500 Canadian 1108 1913 2015 274 132 -143 -100 to -50%

07224500 Canadian 1108 1937 1971 130 -21 -151 > -100%

07227000 Canadian 1108 1912 2012 326 21 -306 -100 to -50%

07228000 Canadian 1109 1939 2015 274 41 -233 -100 to -50%

07237500 North Canadian 1110 1939 2015 195 48 -147 -100 to -50%

07242000 North Canadian 1110 1938 2015 817 1,581 764 50 to 100%
MRG&P Report No. 34 268

Appendix I: Peak Streamflow Analysis by 

HUC-4

Table I-1. Median drainage area-weighted peak discharge (water 

yield) (m3/s/km2) by HUC-4 for all recurrence intervals. 

HUC-4 n Q1.5 Q5 Q10 Q25 Q50 Q100 

0501 88 0.220 0.403 0.500 0.640 0.746 0.843

0502 85 0.329 0.600 0.767 0.951 1.107 1.261

0503 120 0.275 0.461 0.566 0.715 0.831 0.951

0504 83 0.212 0.430 0.561 0.784 0.906 1.105

0505 108 0.322 0.628 0.862 1.203 1.424 1.668

0506 60 0.223 0.420 0.535 0.685 0.772 0.935

0507 43 0.217 0.471 0.636 0.837 0.952 1.199

0508 56 0.297 0.466 0.545 0.700 0.856 1.014

0509 87 0.437 0.858 1.063 1.399 1.785 2.062

0510 92 0.563 1.180 1.516 1.923 2.200 2.438

0511 56 0.625 1.252 1.579 2.108 2.635 3.133

0512 253 0.271 0.540 0.684 0.829 0.947 1.097

0513 147 0.611 1.168 1.445 1.938 2.168 2.453

0514 100 0.944 1.835 2.186 2.559 2.871 3.269

0601 240 0.337 0.701 0.863 1.188 1.442 1.720

0602 55 0.374 0.738 0.939 1.198 1.416 1.645

0603 70 0.569 1.195 1.566 2.087 2.482 2.990

0604 70 0.625 1.367 1.686 2.327 2.813 3.274

0701 80 0.024 0.050 0.063 0.078 0.092 0.108

0702 78 0.044 0.142 0.190 0.283 0.355 0.413

0703 28 0.062 0.143 0.180 0.227 0.261 0.294

0704 80 0.119 0.396 0.570 0.834 1.058 1.287

0705 52 0.118 0.224 0.282 0.331 0.374 0.412

0706 64 0.222 0.653 0.962 1.447 1.868 2.396

0707 75 0.081 0.192 0.245 0.334 0.391 0.454

0708 151 0.151 0.405 0.563 0.806 0.962 1.119

0709 95 0.102 0.225 0.297 0.385 0.464 0.516
MRG&P Report No. 34 269

HUC-4 n Q1.5 Q5 Q10 Q25 Q50 Q100 

0710 75 0.092 0.279 0.344 0.489 0.601 0.715

0711 62 0.329 0.739 0.950 1.234 1.397 1.556

0712 192 0.163 0.309 0.387 0.475 0.534 0.587

0713 92 0.176 0.430 0.575 0.810 1.011 1.164

0714 124 0.644 1.632 2.117 2.701 3.140 3.528

0801 73 0.399 0.769 0.962 1.227 1.442 1.672

0802 73 0.165 0.309 0.367 0.480 0.529 0.564

0803 90 0.652 1.139 1.382 1.684 1.948 2.233

0804 133 0.370 1.037 1.433 1.868 2.391 2.983

0805 17 0.125 0.226 0.267 0.313 0.343 0.370

0806 49 0.965 1.873 2.293 2.778 3.105 3.622

0807 58 0.502 1.347 1.727 2.362 2.726 3.279

0808 55 0.335 0.839 1.172 1.387 1.837 2.361

0809 7 0.433 0.976 1.402 2.092 2.700 3.388

1002 79 0.022 0.044 0.053 0.066 0.075 0.083

1003 106 0.024 0.092 0.159 0.259 0.352 0.474

1004 81 0.023 0.107 0.224 0.412 0.535 0.723

1005 69 0.018 0.098 0.155 0.268 0.350 0.430

1006 47 0.026 0.135 0.273 0.421 0.514 0.605

1007 60 0.044 0.102 0.150 0.200 0.235 0.298

1008 141 0.036 0.102 0.138 0.184 0.218 0.265

1009 106 0.035 0.125 0.170 0.234 0.291 0.349

1010 55 0.043 0.283 0.540 0.955 1.575 2.159

1011 43 0.031 0.143 0.252 0.509 0.726 0.922

1012 138 0.009 0.055 0.095 0.199 0.320 0.446

1013 116 0.017 0.106 0.180 0.297 0.363 0.437

1014 71 0.013 0.103 0.200 0.357 0.525 0.746

1015 44 0.008 0.029 0.051 0.084 0.120 0.167

1016 77 0.005 0.047 0.087 0.168 0.242 0.340

1017 93 0.037 0.161 0.268 0.463 0.585 0.741

1018 146 0.024 0.060 0.089 0.118 0.154 0.183
MRG&P Report No. 34 270

HUC-4 n Q1.5 Q5 Q10 Q25 Q50 Q100 

1019 160 0.028 0.079 0.111 0.151 0.185 0.215

1020 65 0.052 0.199 0.313 0.538 0.933 1.144

1021 45 0.040 0.152 0.201 0.281 0.381 0.528

1022 18 0.018 0.055 0.084 0.140 0.202 0.253

1023 65 0.200 0.619 0.909 1.290 1.820 2.110

1024 63 0.347 1.155 1.483 1.995 2.687 3.175

1025 100 0.009 0.054 0.106 0.206 0.316 0.419

1026 71 0.013 0.086 0.160 0.301 0.473 0.712

1027 87 0.163 0.482 0.661 0.991 1.261 1.493

1028 60 0.218 0.486 0.627 0.809 0.974 1.054

1029 110 0.335 0.897 1.178 1.675 2.032 2.442

1030 75 1.147 2.530 3.193 4.076 4.703 5.370

1101 143 0.482 1.204 1.602 2.318 2.811 3.416

1102 131 0.020 0.090 0.130 0.203 0.265 0.313

1103 77 0.040 0.171 0.256 0.384 0.494 0.615

1104 22 0.036 0.215 0.411 0.709 1.106 1.607

1105 24 0.100 0.483 0.783 1.222 1.577 2.150

1106 26 0.315 2.091 3.409 5.032 6.114 7.184

1107 114 0.190 0.653 0.958 1.392 1.696 1.975

1108 46 0.022 0.084 0.143 0.231 0.332 0.441

1109 29 0.101 0.455 0.654 1.055 1.484 1.972

1110 43 0.014 0.096 0.156 0.328 0.481 0.699

1111 110 0.495 1.431 1.841 2.594 3.150 3.769

1112 32 0.039 0.182 0.274 0.401 0.512 0.650

1113 97 0.107 0.381 0.543 1.014 1.299 1.563

1114 147 0.236 0.819 1.134 1.547 1.838 2.203
MRG&P Report No. 34 271

Appendix J: Suspended-Sediment Yields

Table J-1. Median suspended-sediment yield at the Q1.5 for each HUC-4 along with the 

number of gages and standard error. 

HUC-4 # Stations Median Std. Error 

HUC4 # 

Stations Median 

Std. 

Error 

0501 13 1.13 0.71 1003 9 0.04 0.12

0502 22 2.52 2.2 1004 18 0.1 0.2

0503 20 3.74 4.59 1005 9 0.11 0.38

0504 8 3.21 1.51 1006 7 0.08 0.03

0505 25 1.84 9.74 1007 10 0.03 0.4

0506 7 5.89 0.97 1008 12 1.22 36.7

0507 36 6.85 271 1009 28 1.02 9.7

0508 16 6.76 2.63 1010 35 0.28 69.5

0509 12 6.34 2.24 1011 12 0.09 0.12

0510 19 3.59 3.56 1012 11 0.5 0.77

0511 8 4.58 1.48 1013 30 0.33 1.3

0512 62 4.91 1.89 1014 39 0.25 0.17

0513 34 4.6 11.1 1015 7 13.8 3.3

0514 18 4.45 21.7 1016 10 1.32 1.28

0601 53 4.15 16.3 1017 10 0.01 0

0602 9 1.73 1.14 1018 13 0.19 0.06

0603 9 2.76 1.1 1019 25 0.14 1.25

0604 8 2.2 8.03 1020 30 0.19 1.87

0701 11 0.08 0.03 1021 12 3.4 12.9

0702 15 0.32 1.22 1022 22 11.4 3.11

0703 13 0.1 1.23 1023 8 4.75 17.5

0704 12 31 21 1024 4 0.86 27.9

0705 6 0.28 2.32 1025 7 19.7 115

0706 12 46.9 13.5 1026 18 1.89 299

0707 23 0.76 8.03 1027 12 0.56 0.53

0708 22 0.96 36.5 1028 42 28.3 34.5

0709 43 2.36 1.39 1029 10 14.3 3.85
MRG&P Report No. 34 272

HUC-4 # Stations Median Std. Error 

HUC4 # 

Stations Median 

Std. 

Error 

0710 7 0.62 3.7 1030 11 1.83 11.9

0711 4 7.21 10.1 1101 18 64.1 31.8

0712 36 0.77 1.75 1102 21 2.43 1.16

0713 19 7.34 1.82 1103 48 5.62 1685

0714 11 1.53 367 1104 27 1.67 0.75

0801 20 17.1 26.1 1105 7 2.93 24.8

0802 16 1.01 0.52 1106 8 16.1 5.6

0803 27 154 210 1107 9 4.89 6.54

0804 10 1.26 0.38 1108 67 5.73 3.53

0805 1 3.19 NA 1109 8 0.33 8.53

0806 2 45.1 43 1110 17 4.55 4.23

0807 3 1.16 2.88 1111 22 1.77 6.71

0808 5 2.66 1.06 1112 50 2.99 2.44

0809 1113 16 59.1 103

1002 1 0.77 NA 1114 34 20.7 82

 
MRG&P Report No. 34 273

Table J-2. Suspended-sediment load at the Q1.5 showing changes between the first 

and latest decades of data collection at sediment index stations. Shaded rows 

denote the downstream-most stations for each region (HUC-2). 

HUC-4 Station River 

1st 

decade 

Last 

Decade 

Load at Q1.5 Difference 

1st Last T/d %change 

0502 03085000 Monongahela 1970 1990 28,687 12,264 -16,423 -100 to -50%

0504 03150000 Muskingum 1970 1990 22,683 5,477 -17,206 -100 to -50%

0506 03234500 Scioto 1960 1990 59,048 29,774 -29,274 -50 to -25%

0507 03215000 Big Sandy 1970 1990 65,699 36,435 -29,264 -50 to -25%

0509 03216600 Little Miami 1970 2010 243,309 117,651 -125,658 -100 to -50%

0509 03245500 Ohio 1970 2000 83,674 59,060 -24,614 -50 to -25%

0510 03290500 Kentucky 1970 1990 35,249 33,148 -2,101 -10 to -5%

0512 03374100 Wabash 1970 2010 19,720 25,053 5,333 25 to 50%

0512 03378500 White 1970 2010 54,862 54,860 -2 -5 to 0%

0513 03425000 Cumberland 1970 1990 4,723 4,535 -188 -5 to 0%

0514 03612500 Ohio 1940 2010 588,919 303,106 -285,813 -50 to -25%

0604 03609750 Tennessee 1970 2010 18,038 9,661 -8,377 -50 to -25%

0701 05331580 Mississippi 1970 2010 14,468 15,334 866 5 to 10%

0702 05330000 Minnesota 1970 2000 10,458 11,101 643 5 to 10%

0703 05340500 St Croix 1970 2000 374 1,103 729 > 100%

0704 05382000 Black 1960 2000 1,705 3,241 1,536 50 to 100%

0705 05369500 Chippewa 1960 1990 3,362 7,031 3,669 > 100%

0706 05412500 Turkey 1950 2010 105,508 34,894 -70,614 -100 to -50%

0707 05407000 Wisconsin 1970 2000 3,862 4,712 850 10 to 25%

0708 05465500 Iowa 1970 2010 42,547 16,564 -25,983 -100 to -50%

0709 05446500 Rock 1970 1990 9,159 10,393 1,234 10 to 25%

0710 05490500 Des Moines 1970 2010 53,223 20,215 -33,008 -100 to -50%

0711 05508000 Salt 1970 1990 39,651 5,410 -34,241 -100 to -50%

0712 05543500 Illinois 1970 2000 32,431 12,183 -20,248 -100 to -50%

0713 05586100 Illinois 1980 2010 45,486 18,998 -26,488 -100 to -50%

0714 05594100 Kaskaskia 1970 1990 4,532 7,576 3,044 50 to 100%

0714 07022000 Mississippi 1970 2010 943,146 497,039 -446,107 -50 to -25%

0801 07030050 Hatchie 1970 2000 5,530 1,328 -4,202 -100 to -50%

0802 07077800 White 1980 2010 15,085 10,373 -4,712 -50 to -25%

0803 07288955 Yazoo 1970 2010 72,397 26,110 -46,287 -100 to -50%
MRG&P Report No. 34 274

HUC-4 Station River 

1st 

decade 

Last 

Decade 

Load at Q1.5 Difference 

1st Last T/d %change 

0805 07369500 Tensas 1970 1990 2,657 3,040 383 10 to 25%

0806 07290000 Big Black 1970 1990 18,274 5,425 -12,849 -100 to -50%

0808 07381600

Lower 

Atchafalaya 1970 2010 165,236 115,676 -49,560 -50 to -25%

1003 06054500 Missouri 1970 2000 4,972 3,644 -1,328 -50 to -25%

1004 06115200 Missouri 1970 1990 47,563 35,810 -11,753 -25 to -10%

1005 06174500 Milk 1970 1990 5,613 7,834 2,221 25 to 50%

1006 06181000 Poplar 1970 2000 398 416 18 0 to 5%

1007 06214500 Yellowstone 1970 2000 53,763 45,352 -8,411 -25 to -10%

1008 06294700 Bighorn 1960 1990 130,709 1,703 -129,006 -100 to -50%

1009 06326500 Powder 1970 2010 80,281 58,084 -22,197 -50 to -25%

1010 06329500 Yellowstone 1970 2010 309,387 127,930 -181,457 -100 to -50%

1011 06337000 Little Missouri 1970 1990 253,685 173,695 -79,990 -50 to -25%

1012 06437000 Belle Fourche 1950 1980 187,706 24,104 -163,602 -100 to -50%

1013 06342500 Missouri 1940 2010 253,823 6,826 -246,997 -100 to -50%

1014 06452000 White 1970 2010 1,253,268 256,564 -996,704 -100 to -50%

1015 06465500 Niobrara 1970 1990 41,144 41,979 835 0 to 5%

1016 06478500 James 1970 1990 472 388 -84 -25 to -10%

1017 06485500 Big Sioux 1940 2010 16,729 3,334 -13,395 -100 to -50%

1018 06686000 Platte 1970 1990 3,380 3,187 -193 -5 to 0%

1019 06764000 Platte 1970 1990 1,739 960 -779 -50 to -25%

1020 06805500 Platte 1950 2010 866,411 226,904 -639,507 -100 to -50%

1021 06785000 Loup 1940 1990 170,197 60,360 -109,837 -100 to -50%

1022 06800500 Elkhorn 1940 2010 148,185 96,975 -51,210 -50 to -25%

1023 06607500 Little Sioux 1940 2010 84,367 10,688 -73,679 -100 to -50%

1024 06810000 Nishnabotna 1940 2010 1,286,971 176,457 -1,110,514 -100 to -50%

1025 06856600 Republican 1940 2010 308,184 9,144 -299,040 -100 to -50%

1026 06877600 Smoky Hill 1950 1990 69,431 24,472 -44,959 -100 to -50%

1027 06892350 Kansas 1970 2010 148,497 167,007 18,510 10 to 25%

1029 06926510 Osage 1970 1990 12,339 4,329 -8,010 -100 to -50%

1030 06934500 Missouri 1940 2010 4,000,376 556,987 -3,443,389 -100 to -50%

1101 07074500 White 1970 1990 10,585 10,709 124 0 to 5%

1103 07146500 Arkansas 1940 2000 89,665 41,215 -48,450 -100 to -50%
MRG&P Report No. 34 275

HUC-4 Station River 

1st 

decade 

Last 

Decade 

Load at Q1.5 Difference 

1st Last T/d %change 

1104 07157580 Cimarron 1930 1980 49,014 1,078 -47,936 -100 to -50%

1105 07161000 Cimarron 1940 1990 759,245 60,520 -698,725 -100 to -50%

1106 07150500

Salt Fork 

Arkansas 1930 1980 25,432 523 -24,909 -100 to -50%

1107 07193500 Neosho 1930 1990 37,298 1,964 -35,334 -100 to -50%

1108 07221500 Canadian 1970 2010 13,021 7,381 -5,640 -50 to -25%

1109 07245000 Canadian 1940 1980 388,584 2,899 -385,685 -100 to -50%

1110 07242000 North Canadian 1940 1990 192,606 173,303 -19,303 -25 to -10%

1111 07246500 Arkansas 1940 2010 802,722 34,847 -767,875 -100 to -50%

1111 07250550 Arkansas 1970 2010 17,270 22,088 4,818 25 to 50%

1113 07308500 Red 1970 1990 332,712 285,961 -46,751 -25 to -10%

1113 07331000 Washita 1930 1990 1,399,169 418,235 -980,934 -100 to -50%

1114 07337000 Red 1930 2010 856,235 81,535 -774,700 -100 to -50%

 
MRG&P Report No. 34 276

Table J-3. Median and average annual suspendedsediment loads by HUC-4. 

HUC-4 # Stations 

Avg # 

Flow Years 

Avg of 

Median 

Sediment 

Yield 

Avg of 

Mean 

Sediment 

Yield 

t/y/km2 

0501 7 55.0 17.7 20.2

0502 14 33.5 39.8 41.4

0503 13 52.0 53.2 58.9

0504 6 48.2 46.3 51.2

0505 14 42.5 21.3 27.0

0506 7 55.9 62.6 70.4

0507 14 34.1 272 291

0508 12 66.0 68.1 79.9

0509 9 54.1 57.8 70.0

0510 12 61.2 82.3 98.6

0511 5 67.2 94.2 132

0512 48 48.9 57.4 65.7

0513 15 53.1 85.4 4527

0514 10 50.4 131 136

0601 40 59.4 29.9 37.8

0602 3 45.3 15.9 19.1

0603 5 23.0 29.0 29.8

0604 1 78.0 51.8 58.2

0701 9 45.4 4.7 5.5

0702 15 60.0 30.4 40.3

0703 10 37.3 3.5 3.4

0704 10 33.8 148 182

0705 6 35.8 7.0 7.4

0706 8 60.8 116 231

0707 21 37.5 11.4 35.0

0708 21 64.7 67.9 92.1

0709 36 30.4 19.6 23.2
MRG&P Report No. 34 277

HUC-4 # Stations 

Avg # 

Flow Years 

Avg of 

Median 

Sediment 

Yield 

Avg of 

Mean 

Sediment 

Yield 

t/y/km2 

0710 7 62.0 63.0 105

0711 3 37.3 120 123

0712 30 56.9 34.2 35.6

0713 15 44.9 78.3 105

0714 9 66.2 73 96

0801 9 38.3 182 200

0802 13 41.2 129 132

0803 22 14.4 313 357

0804 9 32.4 26.4 29.8

0805 1 78.0 127 145

0806 1 79.0 112 117

0807 2 41.5 32.7 32.3

0808 1 71.0 50.0 64.3

1002 8 60.6 5.1 6.6

1003 17 44.3 21.1 28.7

1004 5 67.2 9.0 22.6

1005 5 35.8 2.7 4.1

1006 9 38.0 3.0 6.1

1007 11 58.7 29.5 33.9

1008 22 45.0 54.6 99.3

1009 29 32.9 20.7 67.7

1010 11 27.0 8.9 11.6

1011 9 16.2 22.4 32.2

1012 25 28.8 7.6 35.2

1013 32 25.1 7.1 13.7

1014 7 43.1 89.5 126

1015 10 38.0 115 138

1016 10 50.8 0.6 1.3
MRG&P Report No. 34 278

HUC-4 # Stations 

Avg # 

Flow Years 

Avg of 

Median 

Sediment 

Yield 

Avg of 

Mean 

Sediment 

Yield 

t/y/km2 

1017 6 50.5 5.1 8.0

1018 22 37.1 4.9 6.0

1019 23 43.3 12.3 17.1

1020 12 48.7 171 261

1021 18 29.4 514 572

1022 7 47.6 93.7 250

1023 4 79.8 65.6 141

1024 6 65.0 211 290

1025 18 46.3 198 390

1026 11 76.9 5.3 15.7

1027 37 42.1 172 239

1028 8 40.9 256 318

1029 7 37.6 74.8 89.3

1030 11 30.4 88.8 105

1101 11 51.2 21.0 35.0

1102 33 32.6 17.4 40.7

1103 26 57.8 49.8 73.6

1104 4 25.8 38.5 55.2

1105 5 51.2 92.5 121

1106 8 62.4 96.0 148

1107 53 41.8 86.7 120

1108 4 73.3 13.8 30.1

1109 16 39.1 98.7 146

1110 18 46.1 39.8 77.1

1111 36 30.3 68.9 80.8

1112 8 43.6 136 196

1113 27 47.2 220 390

1114 24 48.1 55.3 70.9
MRG&P Report No. 34 279

Table J-4. Summary of changes in median annual suspended-sediment yields within 

each HUC-4 for the period of record. 

HUC-4 

p < 

0.05 

Year 

SuspendedSediment Yield 

[t/y/km2] Change in Yield 

Min Max n 

Min 

Year 

Max 

Year [t/y/km2] %Change 

0501 * 1914 2015 102 13.3 22.9 9.5 50 to 100%

0502 1899 2015 107 49.0 34.4 -14.6 -50 to -25%

0503 1912 2015 104 40.5 51.5 11.0 25 to 50%

0504 1922 2015 94 43.3 51.2 7.9 10 to 25%

0505 * 1878 2015 138 11.6 8.3 -3.3 -50 to -25%

0506 1922 2015 94 61.4 67.3 5.9 5 to 10%

0507 1929 2015 87 117.7 136.3 18.6 10 to 25%

0508 1915 2015 101 92.6 64.2 -28.4 -50 to -25%

0509 1916 2015 97 67.3 51.6 -15.7 -25 to -10%

0510 1908 2015 108 97.3 73.5 -23.8 -25 to -10%

0511 1916 2014 94 85.4 70.6 -14.9 -25 to -10%

0512 * 1904 2015 108 26.3 62.8 36.6 > 100%

0513 1908 2015 103 53.2 63.2 10.0 10 to 25%

0514 1929 2015 87 90.4 78.8 -11.6 -25 to -10%

0601 * 1896 2015 120 66.3 14.6 -51.7 -100 to -50%

0602 1914 2014 101 18.2 22.3 4.1 10 to 25%

0603 1931 2015 73 22.6 21.7 -0.9 -5 to 0%

0604 1926 2015 78 57.1 54.8 -2.3 -5 to 0%

0701 1901 2015 113 3.5 3.4 -0.1 -5 to 0%

0702 * 1905 2015 95 1.7 24.7 23.0 > 100%

0703 * 1902 2015 108 1.2 1.9 0.7 50 to 100%

0704 1910 2015 94 42.7 53.3 10.5 10 to 25%

0705 1929 2015 87 8.4 12.2 3.7 25 to 50%

0706 * 1914 2015 102 236.2 62.8 -173.4 -100 to -50%

0707 * 1914 2015 102 9.7 5.7 -4.0 -50 to -25%

0708 * 1874 2015 142 7.1 51.5 44.4 > 100%

0709 * 1914 2015 102 11.0 25.3 14.3 > 100%

0710 1904 2015 106 17.9 26.0 8.1 25 to 50%

0711 1923 2015 93 43.2 47.5 4.4 10 to 25%
MRG&P Report No. 34 280

HUC-4 

p < 

0.05 

Year 

SuspendedSediment Yield 

[t/y/km2] Change in Yield 

Min Max n 

Min 

Year 

Max 

Year [t/y/km2] %Change 

0712 * 1915 2015 101 17.5 32.0 14.4 50 to 100%

0713 * 1909 2015 104 40.3 73.9 33.6 50 to 100%

0714 * 1863 2015 153 19.5 33.7 14.2 50 to 100%

0801 * 1930 2015 86 64.2 118.4 54.2 50 to 100%

0802 * 1928 2015 88 45.4 88.3 42.9 50 to 100%

0803 * 1936 2015 78 101.8 247.3 145.5 > 100%

0804 * 1929 2015 87 43.0 12.4 -30.6 -100 to -50%

0805 1937 2015 78 126.7 156.7 30.0 10 to 25%

0806 1937 2015 79 99.1 124.9 25.7 25 to 50%

0807 1939 2015 76 33.7 35.2 1.5 0 to 5%

0808 1940 2012 71 65.2 50.4 -14.8 -25 to -10%

0809

1002 * 1890 2015 113 6.7 1.8 -4.8 -100 to -50%

1003 * 1891 2015 125 9.7 4.2 -5.6 -100 to -50%

1004 1931 2015 82 10.6 6.3 -4.2 -50 to -25%

1005 * 1940 2015 76 8.2 2.0 -6.2 -100 to -50%

1006 1909 2015 97 1.3 1.0 -0.4 -50 to -25%

1007 1890 2015 118 37.4 29.1 -8.3 -25 to -10%

1008 * 1913 2015 98 106.7 0.4 -106.3 -100 to -50%

1009 * 1916 2015 95 24.3 5.4 -18.9 -100 to -50%

1010 * 1911 2015 102 94.0 -9.9 -103.9 > -100%

1011 * 1929 2014 86 11.7 5.7 -6.0 -100 to -50%

1012 1930 2015 82 11.4 8.2 -3.2 -50 to -25%

1013 * 1929 2015 87 12.2 5.6 -6.6 -100 to -50%

1014 1929 2014 86 91.8 97.7 6.0 5 to 10%

1015 * 1930 2014 72 11.9 95.9 84.0 > 100%

1016 * 1929 2014 86 0.1 1.4 1.3 > 100%

1017 1929 2014 86 5.6 6.7 1.1 10 to 25%

1018 * 1905 2015 103 1.5 5.1 3.6 > 100%

1019 1885 2015 131 2.3 4.2 1.9 50 to 100%
MRG&P Report No. 34 281

HUC-4 

p < 

0.05 

Year 

SuspendedSediment Yield 

[t/y/km2] Change in Yield 

Min Max n 

Min 

Year 

Max 

Year [t/y/km2] %Change 

1020 * 1931 2015 85 2.5 61.3 58.8 > 100%

1021 1929 2013 85 259.8 254.3 -5.5 -5 to 0%

1022 * 1929 2013 85 50.6 149.6 98.9 > 100%

1023 * 1919 2015 92 14.9 50.9 36.0 > 100%

1024 * 1921 2015 88 11.9 258.8 247.0 > 100%

1025 * 1918 2015 98 40.1 2.4 -37.7 -100 to -50%

1026 * 1896 2015 107 13.4 3.4 -10.1 -100 to -50%

1027 * 1911 2015 102 36.2 85.5 49.3 > 100%

1028 1925 2015 91 280.5 328.5 48.0 10 to 25%

1029 1940 2015 76 127.4 77.0 -50.4 -50 to -25%

1030 * 1929 2015 87 31.0 96.0 65.0 > 100%

1101 1922 2015 94 18.0 22.6 4.6 25 to 50%

1102 1890 2015 125 7.4 11.8 4.3 50 to 100%

1103 1903 2015 97 18.1 10.3 -7.9 -50 to -25%

1104 * 1906 2015 74 44.8 -7.5 -52.3 > -100%

1105 * 1938 2015 78 135.3 38.8 -96.5 -100 to -50%

1106 * 1926 2015 90 46.3 98.8 52.5 > 100%

1107 1896 2015 104 79.4 88.4 9.0 10 to 25%

1108 1907 2015 92 2.7 2.6 -0.1 -5 to 0%

1109 1906 2015 78 202.9 99.6 -103.4 -100 to -50%

1110 * 1903 2015 83 31.7 2.9 -28.9 -100 to -50%

1111 1926 2015 90 44.9 32.5 -12.4 -50 to -25%

1112 * 1904 2015 82 229.0 37.9 -191.1 -100 to -50%

1113 * 1903 2015 92 231.0 108.9 -122.2 -100 to -50%

1114 1906 2015 97 61.7 40.7 -21.0 -50 to -25%
MRG&P Report No. 34 282

Unit Conversion Factors

Multiply By To Obtain 

cubic meter per second 35.3147 cubic feet per second

cubic meter per second 22.83 million gallons per day

kilometers 0.62137 miles

meters 3.281 feet

millimeters 0.03937 inches

square kilometers 0.38610 square miles

square kilometers 247.1 acres

tonnes 2,204.6 pounds (mass)
MRG&P Report No. 34 283

Acronyms and Abbreviations

GHCND Global Historical Climatology Network-Daily 

HUC hydrologic unit code 

IBTrACS International Best Track Archive for Climate Stewardship 

LMR Lower Mississippi River

MVD Mississippi Valley Division

NID National Inventory of Dams 

NOAA National Oceanic Atmospheric Administration

NRCS Natural Resources Conservation Service 

PRCP precipitation

USACE U.S. Army Corps of Engineers

USGS U.S. Geological Survey 
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1. REPORT DATE 

June 2020

2. REPORT TYPE

Final Report

3. DATES COVERED (From - To)

4. TITLE AND SUBTITLE

Changes in Hydrology and Suspended-Sediment Transport in the Mississippi River Basin 

over the Past Century

5a. CONTRACT NUMBER

5b. GRANT NUMBER

5c. PROGRAM ELEMENT NUMBER

6. AUTHOR(S)

Andrew Simon, Kimberly Artita, Gail Simon, Stephen Darby and Julian Leyland 

5d. PROJECT NUMBER

127672

5e. TASK NUMBER

5f. WORK UNIT NUMBER

7. PERFORMING ORGANIZATION NAME(S) AND 

ADDRESS(ES)

Cardno

P.O. Box 1236

Oxford, MS 38655

Department of Geography and Environment

University of Southampton

Highfield

Southampton, SO17 1BJ

UK

8. PERFORMING

ORGANIZATION REPORT

NUMBER

MRG&P Report No. 34

9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES)

US Army Corps of Engineers

Washington, DC 20314-1000

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USACE

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Approved for public release; distribution is unlimited.

13. SUPPLEMENTARY NOTES

14. ABSTRACT

Since about 1900, widespread changes in hydrology across the Mississippi River Basin have occurred, resulting in important changes in 

the delivery of water and sediment to the Lower Mississippi River (LMR). This is due to a combination of natural and anthropogenic 

factors. There have been increases in annual precipitation and 1- to 7-day totals over large parts of the basin. Changes in seasonal 

distributions were also identified, as were increases in hurricane-related rainfall.

Streamflow to the LMR has increased significantly over the past 100 years. Median water yields have increased across most of the midcontinent and decreased in the western-most parts of the Missouri and Arkansas River basins. Suspended-sediment loads to the LMR 

have dramatically declined. The Lower Mississippi River is receiving about 500 million tonnes per year less suspended sediment today 

than in the 1940s (616 Mt/y to 98 Mt/y).

Human impacts on hydrology and sediment transport throughout the basin are important. In the mid-continent, water yield per unit 

precipitation showed increases, but markedly decreased in the western parts of the basin. Decreases can be attributed to the construction 

of thousands of dams, associated flow regulation, withdrawals for agriculture, and to a lesser extent, the increased evaporation behind 

impoundments.

15. SUBJECT TERMS 

Hydrology, Mississippi River, Mississippi River Watershed, Sediment transport, Suspended sediments

16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF 

ABSTRACT

SAR

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297

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a. REPORT David S. Biedenharn

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