Relations Among River Stage, Rainfall, 

Ground-Water Levels, and Stage at Two 

Missouri River Flood-Plain Wetlands

Water-Resources Investigations Report 01–4123

Prepared in cooperation with the

U.S. Environmental Protection Agency

U.S. Department of the Interior

U.S. Geological Survey
Contents iii

CONTENTS

Abstract.............................................................................................................................................................................. 1

Introduction ....................................................................................................................................................................... 2

Study Area ............................................................................................................................................................... 3

Methods ................................................................................................................................................................... 3

Conditions at Wetland NC-5.............................................................................................................................................. 6

Conditions at Wetland TC-1 .............................................................................................................................................. 7

Estimated Ground-Water Levels at Unmeasured Sites...................................................................................................... 10

Relations Among River Stage, Ground-Water Levels, and Wetland Stage ....................................................................... 10

Summary............................................................................................................................................................................ 16

References ......................................................................................................................................................................... 17

FIGURES

1. Map showing location of study area ................................................................................................................. 4

2.–9. Graphs showing: 

2. Water levels at wetland NC-5, well NC-5, and wells NC-5A through NC-5D from June 15, 

1999, to July 6, 2000 ........................................................................................................................... 7

3. Two-day lag time between river stage and stage at wetland NC-5...................................................... 8

4. Daily rainfall, river stage, and wetland NC-5 stage............................................................................. 8

5. Water levels at wetland TC-1 and wells TC-1B through TC-1D from June 15, 1999, to 

July 6, 2000.......................................................................................................................................... 9

6. Two-day lag time between river stage and wetland TC-1 stage, June to August of 1999................... 11

7. One-day lag time between river stage and ground water at wetland TC-1.......................................... 11

8. Rainfall, river stage, and wetland TC-1 stage...................................................................................... 12

9. Wetland TC-1 stage minus river mile 184.15 stage, June 30, 1999, to July 3, 1999........................... 15

TABLES

1. Instrumentation, depths, and dates of measurement at wetlands NC-5 and TC-1................................................. 5

2. Highest and lowest water-level altitudes and dates of occurrence for wetland NC-5 ........................................... 6

3. Highest and lowest water-level altitudes and dates of occurrence for wetland TC-1............................................ 9

4. Comparison of measured and estimated water-level changes at wetland NC-5.................................................... 13

5. Comparison of measured and estimated water-level changes at wetland TC-1 .................................................... 14

6. Estimated water-level changes at wetland NC-3 ................................................................................................... 15
Abstract 1

Relations Among River Stage, Rainfall, Ground-Water 

Levels, and Stage at Two Missouri River Flood-Plain 

Wetlands

By Brian P. Kelly

ABSTRACT

 The source of water is important to the ecological function of Missouri River flood-plain wetlands. There are four potential sources of water to 

flood-plain wetlands: direct flow from the river 

channel during high river stage, ground-water 

movement into the wetlands in response to riverstage changes and aquifer recharge, direct precipitation, and runoff from surrounding uplands. Concurrent measurements of river stage, rainfall, 

ground-water level, and wetland stage were compared for two Missouri River flood-plain wetlands 

located near Rocheport, Missouri, to characterize 

the spatial and temporal relations between river 

stage, rainfall, ground-water levels and wetland 

stage, determine the source of water to each wetland, and compare measured and estimated stage 

and ground-water levels at each site. The two sites 

chosen for this study were wetland NC-5, a nonconnected, 50 feet deep scour constantly filled 

with water, formed during the flood of 1993, and 

wetland TC-1, a shallow, temporary wetland intermittently filled with water. Because these two wetlands bracket a range of wetland types of the 

Missouri River flood plain, the responses of other 

Missouri River wetlands to changes in river stage, 

rainfall, and runoff should be similar to the 

responses exhibited by wetlands NC-5 and TC-1.

For wetlands deep enough to intersect the 

ground-water table in the alluvial aquifer, such as 

wetland NC-5, the ground-water response factor 

can estimate flood-plain wetland stage changes in 

response to known river-stage changes. Measured 

maximum stage and ground-water-level changes 

at NC-5 fall within the range of estimated changes 

using the ground-water response factor. Measured 

maximum ground-water-level changes at TC-1 are 

similar to, but consistently greater than the estimated values, and are most likely the result of alluvial deposits with higher than average hydraulic 

conductivity located between wetland TC-1 and 

the Missouri River.

Similarity between ground-water level and 

stage hydrography at wetland NC-5 indicate that 

ground-water-level fluctuations caused by riverstage changes control the stage of wetland NC-5. 

A 2-day lag time exists between river-stage 

changes and ground water and stage changes at 

wetland NC-5. The lack of a measurable response 

of wetland NC-5 stage to rainfall indicate that rainfall is not a large source of water to wetland NC-5. 

Stage in wetland TC-1 only increased at high river 

stage in June and July 1999, and from runoff 

caused by local rainfall during the winter. The 2-

day lag time between peak stages at wetland TC-1 

and peak Missouri River stages compared to the 1-

day lag time between Missouri River stage and 

ground-water peaks at wetland TC-1 indicates 

ground-water flow does not directly affect wetland 

stage at TC-1, but surface-water flow does affect 

wetland stage at TC-1 during high river stage. 

Comparing wetland TC-1 stage to potential water 

sources indicates the most likely explanation for 

the rise in stage at wetland TC-1 is surface runoff 
2 Relations Among River Stage, Rainfall, Ground-Water Levels, and Stage at Two Missouri River Flood-Plain Wetlands

supplied via seepage through the levees and 

upward flow of ground water through alluvial 

deposits of higher hydraulic conductivity during 

high river stage. The rate of decrease in wetland 

TC-1 stage was limited by the rate at which 

ground-water level decreased. Stage response to 

rainfall at wetland TC-1 during the winter months 

and no response to greater rainfall amounts during 

spring and summer months indicate that evapotranspiration may limit the affect of rainfall on 

stage at wetland TC-1 during the growing season.

INTRODUCTION

Historically, the lower Missouri River flood 

plain was a braided series of oxbow lakes, seasonally 

flooded wetlands, and wooded sloughs. These wetlands 

were created and destroyed by the unregulated meandering and flooding of the Missouri River. Channelization and flood-control projects, initiated in the 1800’s 

and accelerated in the 1940’s, have straightened and 

narrowed the river, making the creation of wetlands 

less likely, and thereby reducing flood-plain habitat for 

fish and wildlife (Funk and Robinson, 1974). 

Upstream, a series of flood-control dams and reservoirs 

have altered the historic flooding patterns and sedimentation loads that impact the flood plain.

Three wetland types remained in the Missouri 

River flood plain before the 1993 flood: remnant wetlands such as oxbows and wooded sloughs, temporary 

or seasonally flooded wetlands, and managed waterfowl areas. Oxbow lakes are large remnants of the Missouri River channel, while wooded sloughs are 

relatively small forested habitats associated with an 

altered drainage ditch, a remnant stream channel, or a 

cutoff main river slough. Temporary wetlands are intermittently inundated and often farmed during dry conditions. Waterfowl areas are diked and hydrologically 

controlled wetland pools intensively managed for concentrating food and habitat for migrating waterfowl. 

Missouri River flood discharges overtopped and 

breached more than 500 levees between Kansas City 

and St. Louis, Missouri, during the flood of 1993. 

These levee breaches accounted for 90 percent of erosion and deposition features of the 1993 flood (Scientific Assessment and Strategy Team, 1994). Breached 

or overtopped levees often left deep, steep-sided scours 

near the levee break with erosional and depositional 

zones occurring downstream from the scour (blew hole, 

blue hole, or blowouts) (Schalk and Jacobson, 1997; 

Galat and others, 1995). About 81,500 acres of lower 

Missouri River flood plain were impacted by scouring 

(Soil Conservation Service, 1993). Two categories of 

scour type were identified: those that are continually 

attached to the river, and those that are non-connected. 

These were identified by the Missouri River Post-flood 

Evaluation Project, a biological project of the Missouri 

Department of Conservation, the Natural Resources 

Conservation Service, and several universities, which 

begun after the flood of 1993. Although these types of 

scour holes are not natural flood-plain habitats, they 

may function as analogs to flood-plain wetlands of 

unregulated rivers. 

The source of water is important to the ecological function of these flood-plain wetlands. There are 

four potential sources of water: direct precipitation, 

runoff from the surrounding uplands, direct flow from 

the river channel during high river stage, and movement of ground water into the wetlands in response to 

river-stage changes and aquifer recharge. Changes in 

wetland stage from direct precipitation are limited by 

the amount of rainfall. Runoff from the surrounding 

uplands can provide water to wetlands on the flood 

plain and is most important for wetlands near the base 

of the river-valley walls, where upland streams enter 

the flood plain, or for wetlands located in or near drainage channels. Direct flow from the river channel during 

high stages can impact all wetland types in the flood 

plain, but is most frequent in areas of the flood plain 

unprotected by levees. Fluctuations in river stage cause 

changes in ground-water levels in the Missouri River 

alluvium. The movement of ground water into wetlands in response to changes in river stage has the greatest effect on wetlands that are deep enough to intersect 

the water table present in the flood plain. 

Questions arise concerning how to most effectively manage flood-plain wetlands. The source of 

water and the magnitude and timing of water-level fluctuations in these wetlands impact water quality, ecological function, and human use. Intensively-managed 

wetland complexes provide abundant habitat for a great 

variety of species. Passive management for flood-plain 

wetlands may provide ideal short-term results; however, wetland water levels dependent on the natural 

hydrology of the flood plain may not consistently provide the desired habitats. Therefore, a need exists to 

better understand relations among water-level changes 

in wetlands and changes in rainfall, runoff, groundwater levels, and river stage. 
Introduction 3

A study was conducted by the U.S. Geological 

Survey (USGS), in cooperation with the U.S. Environmental Protection Agency (USEPA) to evaluate these 

relations for two wetlands located on the Missouri 

River flood plain. The objectives of the study were to 

measure river stage, rainfall, ground-water levels, and 

stage at two Missouri River flood-plain wetland sites, 

and characterize the spatial and temporal relations 

between river stage, rainfall, ground-water levels, and 

wetland stage to infer sources of water to each wetland. 

Data were collected between June 1999 and July 2000. 

The purpose of this report is to present the results of the 

study.

Study Area

 The flood plain of the Missouri River is underlain by alluvial deposits consisting of clays, silts, sands, 

gravels, cobbles, and boulders. In general, the finer 

clays, silts, and sands are located near the surface of the 

alluvium and the coarser sands, gravels, cobbles, and 

boulders are located near the base of the alluvium. 

Numerous investigations have presented lithologic 

cross sections showing a 20- to 30-ft (feet) thick siltclay cap that overlies the sands and gravels of the alluvium in most parts of the lower Missouri River flood 

plain (Kelly and Blevins, 1995; Emmett and Jeffery, 

1968, 1969a, 1969b, 1970). This cap exists in the study 

area and may limit water flow between the land surface 

and the alluvial aquifer. The humid continental climate 

of the study area is characterized by large variations 

and sudden changes in temperature and precipitation. 

The study area receives about 37 inches of rainfall per 

year (Gann and others, 1971). 

The study area is a part of the Missouri River 

flood plain near Rocheport, Missouri. Two wetlands (a 

deep, non-connected scour and a shallow, temporary 

basin) were selected based on minimal or intermittent 

hydrologic interactions with surface water. This minimized changes in wetland stage caused by direct surface-water flow, which allowed more precise 

measurement of the effect of ground-water-level 

changes on wetland stage. The two sites were wetland 

NC-5, a deep, non-connected scour formed during the 

flood of 1993, located at Diana Bend Conservation 

Area (Missouri Department of Conservation) in 

Howard County, and wetland TC-1, a shallow, temporary wetland located in Overton Bottoms in Cooper 

County (fig. 1). The “non-connected” and “temporary” 

designations are from the Missouri River Post-flood 

Evaluation Project. Wetland NC-5 is a scour hole with 

a maximum depth of 50 ft, contains water all year, and 

is located approximately 2,200 ft [670 m (meters)] 

from the Missouri River. Wetland TC-1 intermittently 

contains water and is located approximately 1,540 ft 

(470 m) from the Missouri River. It is relatively shallow 

when water is present, less than 5 ft. In addition to the 

two sites chosen for instrumentation, wetland NC-3, a 

large scour, is located approximately 7,550 ft southeast 

of wetland TC-1, and may have a surface connection to 

wetland TC-1 at high stage. Both wetlands NC-5 and 

TC-1 were protected from direct flooding by the Missouri River during this study by levees. Because these 

two wetlands approximately bracket a range of wetland 

types that currently exist in the Missouri River flood 

plain, the responses of many other Missouri River wetlands to changes in river stage, rainfall, and runoff 

should be similar to the responses exhibited by wetlands NC-5 and TC-1.

Methods

One monitoring well and one cluster of four 

wells of various depths were installed at each site. The 

monitoring well was about 40 ft deep at wetland NC-5 

and about 44 ft deep at wetland TC-1. Ground-waterlevel data collected from the wells provided the information used to determine the relation between ground 

water and wetland stage at the site. The monitoring 

well was located as close to the wetland as possible 

considering site conditions, and the well cluster was 

located within 50 ft of the monitoring well. Each site 

had a data logger with satellite transmission to record 

hourly water levels in the monitoring wells, stage in the 

wetland, and rainfall. All electronically recorded data 

were automatically downloaded to the USGS national 

database every 4 hours. Monthly visits to each site were 

made to manually measure water levels and to service 

and calibrate electronic equipment. 

River stage near each site was estimated using 

linear regression from river stages measured to the 

nearest 0.01 ft concurrently at the USGS streamflow 

gaging station at Boonville, Missouri (river mile 196.6) 

and at a reference point located at the bridge over 

Moniteau Creek near Rocheport, Missouri (fig. 1). 

River stage at river miles 190 and 187.5 were estimated 

using the regression by interpolation along the river 

between the gage at Boonville, Missouri, and the reference point at Moniteau Creek. A total of 12 measurements at Moniteau Creek were compared to
4 Relations Among River Stage, Rainfall, Ground-Water Levels, and Stage at Two Missouri River Flood-Plain Wetlands

Rocheport

USGS

Gaging Station at

Boonville, Missouri,

river mile 196.6

Moniteau

Creek

measuring

point

Flood plain 

connected to 

Missouri River

at river mile 184.15

Diana Bend

Overton Bottoms

EXPLANATION

Wetland

TC-1

ALLUVIAL VALLEY BOTTOM

SCOUR

LEVEE

SITE LOCATION AND IDENTIFIER

RIVER MILE AND IDENTIFIER

TC-1

190

Figure 1. Location of study area.

0 1 2 MILES

0 1 2 KILOMETERS

Study

Area

MISSOURI

Base from U.S. Geological Survey digital data, 1:24,000, 1990

Transverse Mercator projection

Central meridian 93° 00’, origin 00°,00’

uri Misso ver Ri

COOPER

COUNTY

HOWARD

COUNTY

BOONE

COUNTY

92°37’50” 92°32’50”

38°57’50”

39°

92°35’

190

189 188

187

186

185

184

40

70

Wetland

NC-5

Wetland

NC-3

Moniteau

Creek

Unnamed

Creek
Introduction 5

corresponding measurements at Boonville. The coefficient of determination (r2

) of the linear regression is 

0.979. The 95 percent confidence interval for the estimated water levels is plus or minus 0.1 ft. 

Water levels within wells were measured automatically using a shaft encoder, float, and counter 

weight assembly to 0.01-ft accuracy, or a vented pressure transducer to 0.01-ft accuracy. Time and water levels were recorded hourly by a data logger. Hourly 

water-level recordings were checked with monthly 

manual measurements made using an electric waterlevel measuring tape divided into increments of 0.01 ft. 

All reference points of wells were surveyed from a 

nearby benchmark to 0.01-ft accuracy with respect to 

sea level. Water levels were converted to altitude above 

sea level and reported to 0.01-ft accuracy.

The stage in each wetland was recorded using a 

staff gage surveyed to 0.01-ft accuracy with respect to 

sea level. Water levels were converted to altitude above 

sea level and reported to 0.01-ft accuracy. Water levels 

within the wetland were automatically measured to 

0.007-ft accuracy using a vented pressure transducer. 

Time and water levels were recorded hourly by a data 

logger. Pressure readings were calibrated to the staff 

gage readings and converted to altitude above sea level. 

Rainfall was measured in increments of 0.01 

inch with a tipping bucket rain gage. A description of 

instrumentation at each wetland and the time during 

which measurements were made are listed in table 1.

Missing data for ground-water levels were estimated, when necessary, by comparing concurrent measurements of ground water in adjacent wells, and 

Table 1. Instrumentation, depths, and dates of measurement at wetlands NC-5 and TC-1

[Approx., approximately; ft, feet; na, not applicable]

Name Instrument description

Depth of 

well or wetland Dates of measurement

Wetland 

NC-5 gage

Pressure transducer Approx. 50 ft June 15, 1999 to July 6, 2000

Well NC-5 Pressure transducer 39.73 ft July 6, 1999 to July 6, 2000

Well NC-5A Float and counter weight 5.17 ft June 15, 1999 to July 7, 1999

(dry after July 7, 1999)

Well NC-5B Float and counter weight 5.96 ft July 6, 1999 to July 23, 1999

(dry after July 23, 1999)

Well NC-5C Float and counter weight 8.16 ft June 15, 1999 to August 20, 1999

(dry after August 20, 1999)

Well NC-5D Float and counter weight 22.04 ft June 15, 1999 to July 6, 2000

Rain gage NC-5 Tipping bucket rain gage na June 15, 1999 to July 6, 2000

Wetland

TC-1 gage

Pressure transducer Variable June 23, 1999 to July 6, 2000

Well TC-1 Pressure transducer 44.43 ft July 7, 1999 to July 6, 2000

Well TC-1A Float and counter weight 8.5 ft Dry for all measurements

Well TC-1B Float and counter weight 23.86 ft July 7, 1999 to July 6, 2000

Well TC-1C Float and counter weight 14.57 ft June 16, 1999 to August 30, 1999

(dry after August 30, 1999)

Well TC-1D Float and counter weight 10.88 ft June 15, 1999 to August 1, 1999

(dry after August 1, 1999)

Rain gage TC-1 Tipping bucket rain gage na June 23, 1999 to July 6, 2000
6 Relations Among River Stage, Rainfall, Ground-Water Levels, and Stage at Two Missouri River Flood-Plain Wetlands

calculating the missing ground-water data based on the 

average difference between available concurrent measurements. Missing water-level data for wetland NC-5 

were estimated, when necessary, by comparison to 

water levels in well NC-5. Missing water levels in wetland TC-1 were not estimated. Rainfall data were 

recorded without interruption for the study period.

Concurrent measurements of river stage, groundwater level, rainfall, and wetland stage were compared 

for each wetland. Comparison of measured river stage, 

ground-water level, rainfall, and wetland stage was 

used to characterize the relative contribution of each of 

these to changes in wetland stage; the lag time between 

changes in river stage, ground-water level, and rainfall 

to wetland stage; and the relative importance of river 

stage, ground-water level, and rainfall on wetland 

stage.

CONDITIONS AT WETLAND NC-5

The range of river stage, wetland stage, and 

water levels in wells recorded at NC-5 are listed in table 

2. Highest and lowest water levels recorded may not 

correspond to the actual highest and lowest water levels 

that occurred between June 15, 1999, and July 6, 2000, 

because of intermittent gaps in data collection.

Water levels at wetland NC-5 from June 15, 

1999, to July 6, 2000, are shown in figure 2. The 

hydrograph for the Missouri River shows a typical 

change in stage over the course of the year. In spring 

and summer, stages are relatively high because of 

increased releases of water from upstream dams and 

increased rainfall. In fall and winter, river stage is down 

because of decreased releases of water from upstream 

dams and reduced rainfall. Water levels in wetland NC5, well NC-5, and wells NC-5A through NC-5D closely 

follow the trend of river stage, although variation was 

substantially muted. Wells NC-5A, NC-5B, and NC5C became dry during July and August of 1999, as the 

ground-water level decreased below their maximum 

depths, and remained dry for the rest of the study. 

Aligning river-stage peaks near wetland NC-5, 

and water-level peaks at wetland NC-5, well NC-5, and 

wells NC-5A through NC-5D by shifting the time scale 

for the water levels illustrates a lag time of approximately 2 days between river-stage changes and changes 

Table 2. Highest and lowest water-level altitudes and dates of occurrence for wetland NC-5

[Datum is sea level; ft, feet; na, not applicable; <, less than; >, greater than]

Location

Altitude of 

wetland 

bottom

or well 

bottom

(ft)

Highest 

water-level

altitude

(ft)

Date of 

highest 

water level

Lowest 

water-level

altitude

(ft)

Date of 

lowest 

water level or 

when well went 

dry

Waterlevel

range

(ft)

Missouri River at 

river mile 190 na 587.0 July 1, 1999 565.7 February 4, 2000 21.3

Wetland NC-5 525 (approx.) 578.84 July 3, 1999 567.74 February 19, 2000 11.10

Well NC-5 543.24 579.06 July 6, 1999 567.73 February 18, 2000 11.30

Well NC-5A 577.49 579.74 July 3, 1999 <577.83

June 23, 1999 

(well dry) >1.91

Well NC-5B 576.70 578.86 July 6, 1999 <576.70

July 23, 1999 

(well dry) >2.23

Well NC-5C 574.50 579.28 July 3, 1999 <574.62

August 17, 1999 

(well dry) >4.66

Well NC-5D 560.62 579.36 July 3, 1999 567.76 February 18, 2000 11.60
Conditions At Wetland TC-1 7

in wetland stage and ground water at wetland NC-5 

(fig. 3). Daily rainfall, river stage, and wetland NC-5 

stage are shown in figure 4 for the period of this study.

CONDITIONS AT WETLAND TC-1

The range of river stage, wetland stage, and 

water levels in wells recorded at wetland TC-1 are 

listed in table 3. Highest water levels recorded may not 

correspond to the actual highest water levels that 

occurred between June 15, 1999, and July 6, 2000, 

because recorders were inundated in July 1999.

Water levels at wetland TC-1 from June 15, 

1999, to July 6, 2000, are shown in figure 5. Water was 

present about 25 percent of the time in wetland TC-1 

during the period of record. The only time wetland TC1 stage responded to a change in river stage was in June 

and July 1999, during high river stage. Well TC-1 and 

wells TC-1B, TC-1C, and TC-1D follow the trend of 

river stage for the period of record. Well TC-1A 

remained dry for the entire study and wells TC-1C and 

TC-1D became dry in August 1999 as the ground-water 

level decreased below their maximum depths and 

remained dry for the rest of the study. Well TC-1B 

became dry in January 2000 as the ground-water level 

decreased below its maximum depth and remained dry 

until March 2000, when the ground-water level 

increased above its maximum depth. 

The rapid increase in stage at wetland TC-1 and 

in ground-water level in well TC-1D in late June and 

early July 1999 is shown in figure 5. Peak water levels 

in wells were not recorded during the peak and recession of this event because flood waters inundated the 

instrumentation. Water levels in wetland TC-1 and 

wells TC-1C and TC-1D did not exhibit the relatively 

rapid decrease that river stage did following this time. 

Instead, wetland stage and ground-water levels in wells 

TC-1C and TC-1D decreased more slowly and were 

nearly identical from July 7, 1999, to August 2, 1999. 

Water level in well TC-1C did not respond to the river 

stage rise from August 9, 1999, to August 14, 1999, but 

water levels in well TC-1B and well TC-1 increased 

and decreased with river stage (fig. 5).

560

565

570

575

580

585

590

6/15 7/15 8/15 9/15 10/15 11/15 12/15 1/15 2/15 3/15 4/15 5/15 6/15 7/15

ESTIMATED MISSOURI RIVER STAGE AT MILE 190

WETLAND NC-5

WELL NC-5

WELL NC-5A

WELL NC-5B

WELL NC-5C

WELL NC-5D

WATER LEVEL, IN FEET ABOVE SEA LEVEL

1999 2000

Figure 2. Water levels at wetland NC-5, well NC-5, and wells NC-5A through NC-5D from June 15, 

1999, to July 6, 2000.
8 Relations Among River Stage, Rainfall, Ground-Water Levels, and Stage at Two Missouri River Flood-Plain Wetlands

560

565

570

575

580

585

590

6/15 7/15 8/15 9/15 10/15 11/15 12/15 1/15 2/15 3/15 4/15 5/15 6/15 7/15

TIME SCALE FOR MISSOURI RIVER STAGE

6/17 7/17 8/17 9/17 10/17 11/17 12/17 1/17 2/17 3/17 4/17 5/17 6/17 7/17

TIME SCALE FOR WETLAND NC-5 STAGE

ESTIMATED MISSOURI RIVER STAGE AT MILE 190

WETLAND NC-5

1999

1999

2000

2000

Figure 3. Two-day lag time between river stage and stage at wetland NC-5.

WATER LEVEL, IN FEET ABOVE SEA LEVEL

560

565

570

575

580

585

590

6/15 7/15 8/15 9/15 10/15 11/15 12/15 1/15 2/15 3/15 4/15 5/15 6/15 7/15

RAINFALL

ESTIMATED MISSOURI RIVER STAGE AT MILE 190

WETLAND NC-5

STAGE, IN FEET ABOVE SEA LEVEL

Figure 4. Daily rainfall, river stage, and wetland NC-5 stage.

1999 2000

0

0.5

1.0

1.5

2.0

2.5

RAINFALL, IN INCHES
Conditions At Wetland TC-1 9

Table 3. Highest and lowest water-level altitudes and dates of occurrence for wetland TC-1

 [Datum is sea level; ft, feet; na, not applicable; <, less than; >, greater than]

Location

Altitude of 

bottom 

of wetland 

or well 

(ft)

Highest 

waterlevel

altitude

(ft)

Date of 

highest

 water level

Lowest 

waterlevel

altitude

(ft)

Date of 

lowest 

water level or 

when well went 

dry

Waterlevel

range

(ft)

Missouri River

 at 

river mile 187.5 na 584.9 July 1, 1999 563.6 February 4, 2000 21.3

Wetland TC-1 577.60 583.33 July 3, 1999 577.60 August 14, 1999 5.73

Well TC-1 546.32 580.72 July 7, 1999 566.54 February 17, 2000 14.18

Well TC-1A 580.08 dry na dry na na

Well TC-1B 564.72 580.72 July 7, 1999 <567.87

January 19, 2000 

(well dry) >12.85

Well TC-1C 574.01 581.55 July 7, 1999 <574.65

August 30, 1999 

(well dry) >6.9

Well TC-1D 577.70 582.12 July 2, 1999 <577.88

August 1, 1999

(well dry) >4.24

560

565

570

575

580

585

590

6/15 7/15 8/15 9/15 10/15 11/15 12/15 1/15 2/15 3/15 4/15 5/15 6/15 7/15

ESTIMATED MISSOURI RIVER STAGE AT MILE 187.5

WETLAND TC-1

WELL TC-1

WELL TC-1B

WELL TC-1C

WELL TC-1D

1999 2000

Wetland TC-1 dry at 577.6

Figure 5. Water levels at wetland TC-1 and wells TC-1B through TC1-D from June 15, 1999, to 

July 6, 2000.

WATER LEVEL, IN FEET ABOVE SEA LEVEL
10 Relations Among River Stage, Rainfall, Ground-Water Levels, and Stage at Two Missouri River Flood-Plain Wetlands

Aligning river-stage peaks near TC-1 and wetland TC-1 stage peaks by shifting the time scale for the 

water levels (fig. 6) indicate a lag time of approximately 2 days between the peak river stage and the peak 

wetland stage during June and July 1999. Aligning 

river-stage peaks near TC-1 and ground-water level 

peaks at wetland TC-1 by shifting the time scale for the 

ground-water levels (fig. 7) indicate a lag time of 

approximately 1 day or less between peak river stage 

and peak ground-water levels for the period of record. 

With the exception of two periods, December 9, 1999, 

to December 15, 1999, and February 18, 2000, to April 

20, 2000, wetland TC-1 remained dry from August 15, 

1999, to the end of data collection on July 6, 2000 (fig. 

5). Daily rainfall, river stage, and stage for wetland TC1 are shown in figure 8. 

ESTIMATED GROUND-WATER LEVELS 

AT UNMEASURED SITES

Missouri River stage is measured continuously at 

numerous gages along the river. A previous study of the 

lower Missouri River alluvial aquifer in the Kansas 

City metropolitan area (Kelly, 2000) used groundwater flow simulations to develop a relation called the 

ground-water response factor (GWRF) that can be used 

to estimate the response of ground water to river-stage 

changes in the lower Missouri River alluvial aquifer. 

The use of the GWRF assumes that lithology and 

hydraulic properties are similar in the lower Missouri 

River alluvial aquifer. For scours or wetlands deep 

enough to intersect the ground-water table in the alluvial aquifer, such as wetland NC-5, this method can be 

used to estimate flood-plain wetland stage changes in 

response to known river-stage changes, and may provide flood-plain managers with additional knowledge 

of the hydroperiod, the cyclic fluctuation of water, of 

these types of wetlands. The GWRF is defined as the 

change in ground-water level at a known distance from 

the river, divided by the magnitude of the flood pulse at 

a specified time after the beginning of a flood pulse. 

The GWRF is a function of flood-pulse magnitude, distance from the river, and time after the beginning of a 

flood pulse, and is unique for each combination of 

these three values. By multiplying FP (the magnitude 

of the flood pulse or change in river stage) by the 

GWRF determined for that distance and time, the 

GWLC (ground-water-level change) is estimated for 

any magnitude change in river stage. To facilitate the 

comparison of flood-pulse magnitudes and distances 

from the river between data in Kelly (2000) and this 

report, both standard and metric units are used in this 

section. For example, to estimate the change in stage of 

a wetland 500 m from the river, 3 days after a 0.5-mmagnitude, 1-day-duration flood pulse, use the approximate GWRF (from Kelly, 2000; table 15) of 0.056, as 

follows:

GWLC = FP x GWRF

= 0.5 x 0.056

= 0.028 m

The GWRF and corresponding standard deviation were determined for each day after the beginning 

of a flood pulse (GWRF day) at 100-m distance intervals from the Missouri River (Kelly, 2000). A comparison of measured water-level changes, estimated waterlevel changes using the GWRF, and the estimated 

water-level changes within one standard deviation predicted using the GWRF are listed in table 4 for NC-5, 

and table 5 for TC-1. The GWRFs calculated for 600- 

and 700-m distances were used for the comparison with 

water levels at NC-5, located approximately 2,200 ft 

(670 m) from the Missouri River, and GWRFs calculated for 400- and 500-m distances were used for the 

comparison with water levels at TC-1, located approximately 1,540 ft (470 m) from the Missouri River. 

Because wetland TC-1 was dry during most of the 

study period it did not respond directly to groundwater-level changes and water levels from the wetland 

are not included in the comparison.

Measured maximum water-level changes at wetland NC-5 were compared to estimated water-level 

changes using the GWRF and fall within the range of 

predicted changes. Measured maximum water-level 

changes in wells at wetland TC-1 were compared to 

estimated water-level changes using the GWRF and are 

close, but consistently greater than the estimated values 

and are most likely the result of alluvial deposits with 

higher than average hydraulic conductivity located 

between wetland TC-1 and the Missouri River. 

RELATIONS AMONG RIVER STAGE, 

GROUND-WATER LEVELS, AND WETLAND STAGE

The close similarity between the hydrograph of 

wetland NC-5 and the hydrographs of well NC-5 and 

wells NC-5A through NC-5D indicate that fluctuations 

in ground-water level caused by river stage changes 

control the stage of wetland NC-5. As river stage rises, 

water flows from the river into the alluvium, and 
Relations Among River Stage, Ground-Water Levels, and Wetland Stage 11

560

565

570

575

580

585

590

6/15 6/22 6/29 7/6 7/13 7/20 7/27 8/3 8/10 8/17 8/24 8/31

TIME SCALE FOR MISSOURI RIVER STAGE

6/17 6/24 7/1 7/8 7/15 7/22 7/29 8/5 8/12 8/19 8/26 9/2

TIME SCALE FOR WETLAND TC-1 STAGE

ESTIMATED MISSOURI RIVER STAGE AT MILE 187.5

WETLAND TC-1

Figure 6. Two-day lag time between river stage and wetland TC-1 stage, June to August of 1999.

Wetland TC-1 

dry at 577.6

WATER LEVEL, IN FEET ABOVE SEA LEVEL

1999

1999

560

565

570

575

580

585

590

7/16 8/16 9/16 10/16 11/16 12/16 1/16 2/16 3/16 4/16 5/16 6/16 7/16

TIME SCALE FOR GROUND-WATER LEVEL

7/15 8/15 9/15 10/15 11/15 12/15 1/15 2/15 3/15 4/15 5/15 6/15 7/15

TIME SCALE FOR MISSOURI RIVER STAGE

WELL TC-1

WELL TC-1B

ESTIMATED MISSOURI RIVER STAGE AT MILE 187.5

1999

1999

2000

2000

Figure 7. One-day lag time between river stage and ground water at wetland TC-1.

WATER LEVEL, IN FEET ABOVE SEA LEVEL
12 Relations Among River Stage, Rainfall, Ground-Water Levels, and Stage at Two Missouri River Flood-Plain Wetlands

ground-water level rises. With continued high-river 

stage, the rise in ground-water level propagates into the 

alluvium. When river stage decreases, ground-water 

levels nearest the river decrease first, and the decrease 

of ground-water levels also propagates away from the 

river and into the alluvium. The result of these processes is that the response of ground-water levels to 

changes in river stage lag behind the river stage 

changes. Because river-stage fluctuations occur more 

rapidly than the rate at which ground-water levels can 

respond, the magnitude of the change in ground-water 

level at a particular distance from the river usually is 

less than the magnitude of the change in river stage. 

Water levels in flood-plain wetlands deep enough to 

intersect the water table, like wetland NC-5, respond to 

changes in river stage in the same way as ground-water 

levels respond to changes in river stage. The hydrographs shown in figure 2 illustrate the response of 

ground water and stage at wetland NC-5 to river-stage 

fluctuations as described above. The hydrographs of 

river stage and wetland NC-5 stage shifted by time (fig. 

3) indicate a 2-day lag time between river-stage 

changes and changes in ground water and stage at wetland NC-5.

The effect of rainfall on stage at wetland NC-5 is 

difficult to determine for several reasons. In contrast to 

the uplands on either side of the river valley, the relatively flat flood plain limits local runoff during rainfall 

events. Relatively flat topography also limits the predictability of runoff paths if runoff does occur. Rainfall 

events occurred during or about the same time as a rise 

in river stage in June, September, November, and 

December of 1999, and in May and June of 2000 (fig. 

4). Rainfall did not occur without an associated riverstage rise during the study period. In addition, any stage 

increase from direct rainfall onto the water surface is 

difficult to measure because the bottom of wetland NC5 intersects the highly permeable sands of the alluvial 

aquifer. A rainfall event of sufficient intensity to overcome the rate at which water is transmitted from wetland NC-5 to the aquifer did not occur during the study 

period. With these limitations in mind, the lack of measurable response of wetland NC-5 stage to rainfall 

events indicates that direct rainfall and runoff have an 

undetectable affect on stage, and are not a major source 

of water to NC-5. However, other scours similar to NC5 could provide large amounts of focused recharge to 

the underlying alluvial aquifer if they received significant runoff from the uplands.

0

0.5

1.0

1.5

2.0

2.5

3.0 560

565

570

575

580

585

590

6/15 7/15 8/15 9/15 10/15 11/15 12/15 1/15 2/15 3/15 4/15 5/15 6/15 7/15

Rainfall

RAINFALL

ESTIMATED MISSOURI RIVER STAGE AT MILE 187.5

WETLAND TC-1

RAINFALL, IN INCHES

STAGE, IN FEET ABOVE SEA LEVEL

1999 2000

Figure 8. Rainfall, river stage, and wetland TC-1 stage.

Wetland TC-1

dry at 577.6
Relations Among River Stage, Ground-Water Levels, and Wetland Stage 13

The hydrologic response of wetland TC-1 to 

river stage, ground water, rainfall, and runoff was very 

different than the response exhibited by wetland NC-5. 

The hydrographs of water levels shown in figure 5 

illustrate the response of ground water and stage at wetland TC-1 to river-stage fluctuations. For the period of 

record, stage in wetland TC-1 only increased during 

high river stage and from runoff caused by local rainfall. Before July 1999, the ground-water level in well 

TC-1D was higher than wetland TC-1 stage, indicating 

upward ground-water flow into wetland TC-1. River 

stage never became higher than the surrounding levees 

upstream from wetland TC-1 during the study period. 

Water levels in wetland TC-1 were, however, higher or 

nearly the same as ground-water levels near wetland 

TC-1. Between July 1, 1999 and August 15, 1999, rainfall was not sufficient to explain the increase in wetland 

TC-1 stage above ground-water level (fig. 5). In addition, the 2-day lag time between peak stage at wetland 

TC-1 and peak stage on the Missouri River, compared 

to the 1-day lag time between the river and groundwater levels at TC-1, indicate a less direct hydraulic 

connection between the river and the wetland. High 

resolution elevation data provided by the USACE (Kim 

Penner, U.S. Army Corps of Engineers, written commun., 2000) indicate that at stages above 579.5 ft, wetTable 4. Comparison of measured and estimated water-level changes at wetland NC-5

[Max., maximum; ft, feet; GWRF, ground-water response factor; m, meter; STD, standard deviation; High, using GWRF+STD for 1,969-ft distance; 

Low, using GWRF-STD for 2,297-ft distance]

Well or

scour

Max.

waterlevel

change

(ft)

Day of

max.

waterlevel

change

Waterlevel

change/

 riverstage

change

GWRF

day

Simulated GWRF value

Estimated maximum

water-level change (ft)

1,969 ft 

(600 m) 

distance STD

2,297 ft

(700 m) 

distance STD High

1,969 ft

(600 m) 

distance

2,297 ft

(700 m) 

distance Low

Event beginning on 6-28-99 and ending on 7-15-99. 

Maximum river stage change was 9.87 ft (3.01 m) on 7-1-99 (event day 4). GWRF from 8-day, 3-m simulation results

Wetland 

NC-5 0.92 7-3-99 0.093 6 0.181 0.118 0.135 0.101 2.95 1.79 1.33 0.34

Well 

NC-5A 1.75 7-3-99 .177 6 .181 .118 .135 .101 2.95 1.79 1.33 .34

Well 

NC-5C 1.41 7-3-99 .143 6 .181 .118 .135 .101 2.95 1.79 1.33 .34

Well

NC-5D 1.30 7-3-99 .132 6 .181 .118 .135 .101 2.95 1.79 1.33 .34

Event beginning on 8-9-99 and ending on 8-16-99. 

Maximum river stage change was 3.95 ft (1.2 m) on 8-11-99 (event day 3). GWRF from 8-day, 1-m simulation results.

Wetland

NC-5 0.28 8-13-99 0.071 5 0.115 0.088 0.079 0.070 0.802 0.454 0.312 0.036

Well 

NC-5 .39 8-12-99 .099 4 .091 .077 .060 .059 .664 .36 .237 .004

Well 

NC-5C .30 8-13-99 .076 5 .115 .088 .079 .070 .802 .454 .312 .036

Well 

NC-5D .41 8-12-99 .104 4 .091 .077 .060 .059 .664 .36 .237 .004

Event beginning on 9-27-99 and ending on 10-17-99. 

Maximum river stage change was 3.04 ft (0.93 m) on 9-29-99 (event day 3). GWRF from 8-day, 1-m simulation results.

Wetland 

NC-5

0.8 10-3-99 0.263 7 0.162 0.107 0.117 0.089 0.818 0.492 0.356 0.085

Well 

NC-5

.45 10-1-99 .148 5 .115 .088 .079 .070 .617 .349 .240 .027

Well 

NC-5D

.44 10-1-99 .144 5 .115 .088 .079 .070 .617 .349 .240 .027
14 Relations Among River Stage, Rainfall, Ground-Water Levels, and Stage at Two Missouri River Flood-Plain Wetlands

land TC-1 has a surface connection to wetland NC-3, 

the large scour near I-70 located approximately 765 ft 

(233 m) from the Missouri River and approximately 

7,550 ft (2,300 m) southeast of wetland TC-1 (fig. 1). 

In addition, wetland NC-3 is connected to the Missouri 

River for river stages above 580.6 ft at river mile 

184.15, downstream from wetland NC-3. 

The potential effect on wetland TC-1 stage by a 

change in wetland NC-3 stage can be evaluated by estimating the maximum water level change for wetland 

NC-3 during July 1999 using the GWRF (table 6) and 

comparing stages between wetlands TC-1 and NC-3. 

This method can estimate stage changes in wetland 

NC-3 caused only by ground-water-level changes in 

response to river stage changes, and not a change in 

wetland NC-3 stage caused by a surface connection to 

the river.

The measured responses of ground-water level to 

river-stage changes at wetland TC-1 were consistently 

greater than water-level changes estimated using the 

GWRF. For this reason, the high estimate listed in table 

6 for the maximum stage change at wetland NC-3 was 

chosen for the comparison to wetland TC-1 stage. The 

maximum estimated stage at wetland NC-3 was 580.38 

ft; the maximum measured stage at wetland TC-1 during this same event was 583.31 ft. The higher stage at 

wetland TC-1 indicates that wetland NC-3 stage 

changes in response to river-stage changes did not back 

water into wetland TC-1 at the peak. However, the estimate for maximum stage at wetland NC-3 was greater 

than 579.5 ft, the altitude at which TC-1 and NC-3 have 

a surface connection, indicating that wetland NC-3 

stage changes can, at times, affect stage at wetland TC1. As previously stated, wetland NC-3 connects to the 

river at stages above 580.6 near river mile 184.15. During the study period, this connection to the river only 

occurred between June 30, 1999, and July 3, 1999, 

when river stage exceeded 580.6 at river mile 184.15. 

Wetland TC-1 stage minus stage for river mile 184.15 

between June 30, 1999, and July 3, 1999, is shown in 

figure 9. Wetland TC-1 stage is less than river stage on 

June 30, 1999, and July 1, 1999, and then rises above 

river stage on July 2, 1999, and July 3, 1999. The maximum difference between wetland TC-1 stage and river 

stage on June 30, 1999, and July 1, 1999, was -0.78 ft 

(altitude 580.3 at river mile 184.15). Because wetland 

TC-1 stage increased to at least 583.3 ft on July 3, 

1999, (3.41 ft higher than the river at mile 184.15) a 

source of water other than the direct connection to the 

river at mile 184.15 was the cause of the stage increase.

There was little or no precipitation on the 9 days 

before the increase in stage beginning on June 30, 

1999, at wetland TC-1; wetland TC-1 was protected 

from upstream flooding by levees during this study. A 

levee located about 2,200 ft west of wetland TC-1 lies 

between the wetland and the unprotected part of the 

flood plain upstream from wetland TC-1 at river mile 

188. River stage, estimated using the regression and 

Table 5. Comparison of measured and estimated water-level changes at wetland TC-1

[ft, feet; GWRF, ground-water response factor; m, meter; STD, standard deviation; High, using GWRF+STD for 1,312-ft distance; Low, using GWRFSTD for 1,640-ft distance]

Well

Maximum

waterlevel

change

(ft)

Day of

maximum

waterlevel

change

Waterlevel

change/

 riverstage

change

GWRF

day

Simulated GWRF value

Estimated maximum

water-level change (ft)

1,312 ft

(400 m) 

distance STD

1,640 ft

(500 m) 

distance STD High

1,312 ft

(400 m) 

distance

1,640 ft

(500 m) 

distance Low

Event beginning on 8-9-99 and ending on 8-16-99. 

Maximum river stage change was 3.95 ft (1.2 m) on 8-11-99 (event day 3). GWRF from 8-day, 1-m simulation results.

Well 

TC-1

1.72 8-11-99 0.435 3 0.192 0.129 0.120 0.096 1.26 0.758 0.474 0.948

Well 

TC-1B

1.32 8-11-99 .334 3 .192 .129 .120 .096 1.26 .758 .474 .948

Event beginning on 9-27-99 and ending on 10-17-99. 

Maximum river stage change was 3.04 ft (0.93 m) on 9-29-99 (event day 3). GWRF from 8-day, 1-m simulation results.

Well 

TC-1 1.19 9-30-99 0.39 4 0.233 0.142 0.153 0.109 1.14 0.708 0.465 0.134

Well 

TC-1B 1.18 9-30-99 .388 4 .233 .142 .153 .109 1.14 .708 .465 .134
Relations Among River Stage, Ground-Water Levels, and Wetland Stage 15

Table 6. Estimated water-level changes at wetland NC-3

[GWRF, ground-water response factor; ft, feet; m, meter; STD, standard deviation; High, using GWRF+STD at 656-ft distance; Low, using GWRF-STD at 

984-ft distance]

Well or

scour

GWRF

day

Simulated GWRF value

Estimated maximum

water-level change (ft)

Estimated maximum

stage (ft)

656 ft

(200 m) STD

984 ft

(300 m) STD High

656 ft

(200 m) 

distance

984 ft

(300 m) 

distance Low High

656 ft

(200 m) 

distance

984 ft

(300 m) 

distance Low

Event beginning on 6-28-1999 and ending on 7-15-1999. 

Maximum river stage change was 9.87 ft (3.01 m) on 7-1-99 (event day 4). GWRF from 8-day, 3-m simulation results

Wetland

NC-3 4 0.562 0.224 0.378 0.189 7.75 5.55 3.73 1.86 580.38 578.18 576.36 574.49

-1.5

-1.0

-0.5

0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

6/30 7/1 7/2 7/3

STAGE AT WETLAND TC-1 MINUS STAGE AT MISSOURI RIVER MILE 184.15, IN FEET

1999

Figure 9. Wetland TC-1 stage minus river mile 184.15 stage, June 30, 1999, to July 3, 1999.
16 Relations Among River Stage, Rainfall, Ground-Water Levels, and Stage at Two Missouri River Flood-Plain Wetlands

interpolation methods previously discussed, at river 

mile 188 peaked at 585.3 on July 1, 1999, at 6:00 p.m. 

River stage at river mile 187.5 peaked at 584.9 on July 

1, 1999, at 6:00 p.m. At this stage, water was within 

about 5 ft of the levee top. The most likely explanation 

for the rise in stage at wetland TC-1 during this time is 

surface water supplied to the flood plain via seepage 

through the levees, and upward flow of ground water 

through alluvial deposits of relatively high hydraulic 

conductivity driven by the hydraulic gradient between 

the river and the flood-plain surface during high-river 

stage.

During the recession of water levels at wetland 

TC-1 after July 1, 1999, stage remained above or nearly 

equal to shallow ground-water levels, indicating infiltration of water from TC-1 into the alluvial aquifer. 

This pattern indicates that TC-1 stage and shallow 

ground-water levels are closely related, that the rate of 

decrease in wetland stage was limited by the rate at 

which ground-water level decreased, and that the wetland was a source of recharge to the alluvial aquifer 

during this time. 

TC-1 remained dry after August 15, 1999, except 

for two periods, once in December 1999 and again 

from February to April 2000. The presence of water in 

wetland TC-1 from December 9, 1999, to December 

15, 1999, was caused by 4.78 inches of rainfall between 

November 11, 1999, and December 9, 1999. The 2.53 

inches of rainfall between November 11, 1999, and 

December 8, 1999, most probably saturated the soil 

column enough to allow runoff to develop within the 

small basin that drains into wetland TC-1 from the 2.25 

inches of rainfall on December 9, 1999. This scenario 

is supported by the 2.88-ft (34.56-inch) rise in wetland 

TC-1 stage on December 9, 1999 (fig. 7). Between 

December 15, 1999, and February 16, 2000, 1.29 

inches of rain fell in several small events without reappearance of water in wetland TC-1. On February 17, 

1999, 0.64 inch of rain followed by 1.12 inches of rain 

on February 18, 1999, resulted in a 0.11-ft (1.27-inch) 

rise in wetland TC-1 stage. On February 25, 2000, 1.57 

inches of rain caused wetland TC-1 stage to rise 0.49 ft 

(5.85 inches) by February 26, 2000. Between February 

27, 2000, and April 20, 2000, 3.65 inches of rain fell in 

several small events, and wetland TC-1 water depths 

remained at or below 0.1 ft. From April 21, 2000, to the 

end of data collection on July 6, 2000, a total of 15.03 

inches of rain fell. The largest event, 2.67 inches, 

occurred on May 26, 2000. During this time wetland 

TC-1 remained dry. 

The average rates of decrease of wetland TC-1 

stage after the stage increases of December 9, 1999, 

and February 25, 2000, were 0.55 and 0.7 inches per 

hour, respectively. Because wetland TC-1 has no outlet 

for surface-water flow at stages below about 1.9 ft, and 

because evapotranspiration was negligible at that time 

of year, these decreases in stage represent water flow 

from wetland TC-1 into ground water and indicate the 

infiltration rate of the bottom material in the wetland. 

Wetland TC-1 stage response to rainfall during the winter months and the lack of response to greater rainfall 

amounts during spring and summer months indicate 

that evapotranspiration may limit the effect of rainfall 

on wetland stage at TC-1 during the growing season.

Wetlands NC-5 and TC-1 may approximately 

represent two morphologic end members of wetland 

types found in the Missouri River flood plain. Deep 

scours like wetland NC-5 contain water throughout the 

year. The bottoms of these scours may intersect the 

highly conductive sand of the underlying alluvial aquifer allowing a relatively rapid exchange of water 

between the scour and ground water. Ground-water 

fluctuations caused by river-stage changes have a large 

effect on water levels in these deep, non-connected 

scours. Temporary wetlands like TC-1 usually are shallow depressional features that have bottom material 

with low permeability. These wetlands have significantly less interaction with ground water because of 

their lack of depth and low-permeability bottom material. As a result, water levels respond to local rainfall 

and runoff to a greater degree than the larger scours. 

Because these two wetlands may approximately represent morphological end members of a continuum of 

wetlands in the Missouri River flood plain, the 

responses of many other wetlands to changes in river 

stage, rainfall, and runoff should fall within the range 

of the responses exhibited by wetlands NC-5 and TC-1. 

SUMMARY

 The source of water is important to the ecological function of flood-plain wetlands. There are four 

potential sources of water to flood-plain wetlands: 

direct flow from the river channel during high river 

stage, movement of ground water into the wetlands in 

response to river-stage changes, direct precipitation, 

and runoff from the surrounding uplands. The source of 

water and the magnitude and timing of water-level fluctuations in these water bodies may affect water quality, 

ecological function, and use. This report presents con-
References 17

currently measured river stage, rainfall, ground-water 

levels, and wetland stage at two wetlands located on the 

Missouri River flood plain near Rocheport, Missouri. 

Wetland NC-5 is a permanent scour hole up to 50 feet 

deep and is under water all year. Wetland TC-1 is a temporary wetland where water is not present all year. 

Because these two wetlands may approximately represent two morphological end members of wetland types 

found in the Missouri River flood plain, the responses 

of other wetlands to changes in river stage, rainfall, 

ground-water-level changes, and runoff should fall 

within the range of the responses exhibited by wetlands 

NC-5 and TC-1.

One monitoring well and one cluster of four 

wells of various depths were installed at each site to 

collect ground-water-level data. A linear regression 

from river stages concurrently measured at the U.S. 

Geological Survey streamflow gaging station at Boonville, Missouri, and at a reference point located at the 

bridge over Moniteau Creek near Rocheport, Missouri, 

was developed and river stage near wetlands NC-5 and 

TC-1 were estimated by interpolation along the river 

between the two points. Rainfall was measured with a 

tipping bucket rain gage. Time and water levels were 

recorded by a data logger at hourly intervals.

Concurrent measurements of river stage, rainfall, 

ground-water level, and wetland stage were compared 

for each wetland to characterize the relative contribution and importance of potential sources of water on 

wetland stage. For scours such as wetland NC-5 or wetlands deep enough to substantially intersect the 

ground-water table in the alluvial aquifer, the groundwater response factor (GWRF) can be used to estimate 

water-level changes in response to known river-stage 

changes, and may provide flood-plain managers with 

additional knowledge of the hydroperiod of these types 

of wetlands. Measured maximum water-level changes 

at wetland NC-5 estimated using the GWRF fell within 

the range of predicted changes. Measured maximum 

ground-water-level changes at wetland TC-1 are similar to but consistently greater than the estimated values, 

and are most likely the result of alluvial deposits with 

higher than average hydraulic conductivity located 

between wetland TC-1 and the Missouri River.

The close similarity between stage at wetland 

NC-5 and the ground-water levels in wells at wetland 

NC-5 indicate that fluctuations in ground-water level 

caused by changes in river stage control the stage of 

wetland NC-5. The hydrographs of river stage and wetland NC-5 stage shifted by time indicate a 2-day lag 

time between river stage changes and changes in 

ground water and stage at wetland NC-5. The lack of a 

measurable response of wetland NC-5 stage to rainfall, 

and the isolation of wetland NC-5 from runoff and 

flooding by levees, indicate that direct rainfall and runoff are minimal sources of water to wetland NC-5.

The most likely explanation for the rise in stage 

at wetland TC-1 is surface runoff supplied to the flood 

plain via seepage through the levees, and upward flow 

of ground water through alluvial deposits of higher 

hydraulic conductivity during high river stage. The rate 

of decrease in wetland TC-1 stage was limited by the 

rate at which ground-water level decreased. Wetland 

TC-1 stage response to rainfall during the winter 

months and no response to greater rainfall amounts 

during spring and summer months indicate that evapotranspiration may limit the affect of rainfall on stage at 

wetland TC-1 during the growing season.

REFERENCES

Emmett, L.F., and Jeffery, H.G., 1968, Reconnaissance 

of the ground-water resources of the Missouri 

River alluvium between St. Charles and Jefferson 

City, Missouri: U.S. Geological Survey Hydrologic Investigations Atlas HA–315, 1 sheet, scale 

1:125,000.

——— 1969a, Reconnaissance of the ground-water 

resources of the Missouri River alluvium between 

Kansas City, Missouri and the Iowa border: U.S. 

Geological Survey Hydrologic Investigations 

Atlas HA–336, 1 sheet, scale 1:125,000.

——— 1969b, Reconnaissance of the ground-water 

resources of the Missouri River alluvium between 

Jefferson City and Miami, Missouri: U.S. Geological Survey Hydrologic Investigations Atlas HA–

340, 1 sheet, scale 1:125,000.

——— 1970, Reconnaissance of the ground-water 

resources of the Missouri River alluvium between 

Miami and Kansas City, Missouri: U.S. Geological Survey Hydrologic Investigations Atlas HA–

344, 1 sheet, scale 1:125,000.

Funk, J.L., and Robinson, J.W., 1974, Changes in the 

channel of the lower Missouri River and effects on 

fish and wildlife: Missouri Department of Conservation Aquatic Service, 112 p.

Galat, D.L., Kubisiak, J.F., Hooker, J.B., and Sowa, 

L.F., 1995, Geomorphology, distribution and connectivity of lower Missouri River flood plain water 
18 Relations Among River Stage, Rainfall, Ground-Water Levels, and Stage at Two Missouri River Flood-Plain Wetlands

bodies scoured by the flood of 1993: Verh Internat. 

Verein. Limnol. 26.

Gann, E.E., Harvey, E.J., Barks, J.H., and Fuller, D.L., 

1971, Water resources of northeastern Missouri: 

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Atlas HA–372, 4 sheets.

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KELLY—Relations Among River Stage, Rainfall, Ground-Water Levels, and Stage—USGS WRIR 01–4123

at Two Missouri River Flood-Plain Wetlands