Sether, Berkas, and Vecchia–Constituent Loads and Flow-Weighted Average Concentrations for Major Subbasins of the

Upper Red River of the North Basin, 1997-99–Scientific Investigations Report 2004–5200

In cooperation with the North Dakota Department of Health, Minnesota Pollution Control 

Agency, Red River Joint Water Resource Board, and Red River Watershed Management Board

Constituent Loads and Flow-Weighted Average 

Concentrations for Major Subbasins of the

Upper Red River of the North Basin, 1997-99

Scientific Investigations Report 2004–5200

U.S. Department of the Interior

U.S. Geological Survey Printed on recycled paper

97 ̊00' 96 ̊30'

46 ̊30'

47 ̊00'

75

81

81

10

10

75

59

94

94

29

29

210

108

18

46

18

18

27

11 11 55

13

9

9

9

32

113

Creek

Creek

Creek Creek

Whiskey

Creek

Stony

Deerhorn

Creek

Wolverton Whiskey

Antelope

Wild

Rice

River

River

River

River

River

Pelican

R.

Rabbit

Bois De Sioux

Otter

Tail

River

River River Lower Rush R. Br. River

River

River

RED

RIVER

OF

THE

NORTH

River

Buffalo Buffalo

Wild

Wild

South

Branch

Rice

Rice

Elm

 South Elm R. Rush Maple Sheyenne

South Branch

Mapleton West FARGO Moorhead

Fargo

Harwood

Horace Wild Rice

Hickson

Abercrombie

Wahpeton Breckenridge

Barnesville

Doran

Fergus

Falls

Georgetown

Perley

CASS CO.

CASS CO.

RICHLAND CO.

RANSOM CO.

RANSOM CO.

CLAY CO.

CLAY CO. BECKER CO.

NORMAN CO.

WILKIN CO.

WILKIN CO.

OTTER TAIL CO.

OTTER TAIL CO

.

GRANT CO.

SARGENT CO.

TRAILL CO.

11

10

9

8

7

6

5

4

1

3

2
Constituent Loads and Flow-Weighted 

Average Concentrations for Major Subbasins of the Upper Red River ofthe North Basin, 1997-99By Bradley A. Sether, W. R. Berkas, and A. V. Vecchia
U.S. Department of the Interior

Gale A. Norton, SecretaryU.S. Geological SurveyCharles G. Groat, DirectorU.S. Geological Survey, Reston, Virginia: 2004For sale by U.S. Geological Survey, Information Services

Box 25286, Denver Federal CenterDenver, CO 80225For more information about the USGS and its products:Telephone: 1-888-ASK-USGSWorld Wide Web: http://www

usgs

gov/
 iii

ContentsAbstract. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Purpose and scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2Description of Red River of the North Basin. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2Study design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6Methods. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Sample collection and analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6Load computation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Water-quality characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Biochemical oxygen demand . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10Bacteria . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10Dissolved solids. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11Nutrients. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Nitrogen. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13Phosphorus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

Suspended sediment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

Constituent loads and flow-weighted average concentrations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
iv 

Contents, Continued

Table 1-6. Estimated annual total nitrogen loads and flow-weighted average

concentrations for the upper Red River of the North Basin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55

Table 1-7. Estimated annual total phosphorus loads and flow-weighted average

concentrations for the upper Red River of the North Basin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57

Table 1-8. Estimated annual dissolved phosphorus loads and flow-weighted

average concentrations for the upper Red River of the North Basin . . . . . . . . . . . . . . . . . . . . . . . . . . 59

Table 1-9. Estimated annual suspended-sediment loads and flow-weighted

average concentrations for the upper Red River of the North Basin . . . . . . . . . . . . . . . . . . . . . . . . . . 61

Figures

1. Map showing location of study area, locations of water-quality sampling sites,

land use and land cover, and physiographic areas in the Red River of the NorthBasin. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3

2. Map showing mean annual precipitation and streamflow in the Red River of

the North Basin. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5

3. Diagram showing sample-collection timelines for water-quality sampling sites

used in study . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8

4. Graph showing distribution of 5-day biochemical oxygen demand in the upper

R

d Ri

f th

N

th B

i

d

i

M

1997 th

h S

t

b

1999

10
 v

Figures, Continued

19. Graph showing mean daily streamflow for the Sheyenne River at West Fargo,

North Dakota, streamflow-gaging station for water years 1997, 1998, and 1999 . . . . . . . . . . . . . . . . . . . . 25

20. Graphs showing estimated annual dissolved-solids loads and flow-weighted

average concentrations for 1998-99 (loads not shown for main-stem sites). . . . . . . . . . . . . . . . . . . . . . . . 28

21. Graphs showing estimated annual total nitrite plus nitrate loads and flow-weighted

average concentrations for 1998-99 (loads not shown for main-stem sites). . . . . . . . . . . . . . . . . . . . . . . . 29

22. Graphs showing estimated annual total ammonia loads and flow-weighted average

concentrations for 1998-99 (loads not shown for main-stem sites). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

23. Graphs showing estimated annual total organic nitrogen loads and flow-weighted

average concentrations for 1998-99 (loads not shown for main-stem sites). . . . . . . . . . . . . . . . . . . . . . . . 31

24. Graphs showing estimated annual total nitrogen loads and flow-weighted average

concentrations for 1998-99 (loads not shown for main-stem sites). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

25. Graphs showing estimated annual total phosphorus loads and flow-weighted

average concentrations for 1998-99 (loads not shown for main-stem sites). . . . . . . . . . . . . . . . . . . . . . . . 33

26. Graphs showing estimated annual dissolved phosphorus loads and flow-weighted

average concentrations for 1998-99 (loads not shown for main-stem sites). . . . . . . . . . . . . . . . . . . . . . . . 34

27. Graphs showing estimated annual suspended-sediment loads and flow-weighted

average concentrations for 1998-99 (loads not shown for main-stem sites). . . . . . . . . . . . . . . . . . . . . . . . 35

Tables
Constituent Loads and Flow-Weighted Average 

Concentrations for Major Subbasins of theUpper Red River of the North Basin, 1997-99By Bradley A. Sether, W. R. Berkas, and A. V. VecchiaAbstract

Data were collected at 11 water-quality sampling sites in 

the upper Red River of the North (Red River) Basin from May 1997 through September 1999 to describe the water-quality characteristics of the upper Red River and to estimate constituent loads and flow-weighted average concentrations for major 

tributaries of the Red River upstream from the bridge crossing the Red River at Perley, Minn. Samples collected from the sites were analyzed for 5-day biochemical oxygen demand, bacteria, dissolved solids, nutrients, and suspended sediment.

Results were used as a screening tool to identify which subbasins contributed a disproportionate amount of pollutants to the 

Red River. To compare the relative water quality of the different subbasins, an estimated flow-weighted average (FWA) concentration was computed from the estimated average annual load and the average annual streamflow for each subbasin.

The 5-day biochemical oxygen demands in the upper Red 

River Basin were fairly small, and medians ranged from 1 to 3 milligrams per liter. The largest estimated FWA concentration for dissolved solids (about 630 milligrams per liter) was for 

the Bois de Sioux River near Doran, Minn., site. The Otter Tail River above Breckenridge

Minn

site had the smallest esti
2 Constituent Loads and Flow-Weighted Average Concentrations for the Upper Red River of the North Basin, 1997-99

nitrate concentrations, which increased about fivefold between the Red River below Wahpeton, N. Dak., site and the Red River 

at Perley, Minn., site.

The Red River near Harwood, N. Dak., to the Red River at 

Perley, Minn., intervening reach had the largest estimated FWA concentration for total nitrogen (about 2.9 milligrams per liter), but the estimate was highly uncertain. The Otter Tail River above Breckenridge, Minn., site had the smallest concentration (about 0.6 milligram per liter). The estimated FWA concentrations for total nitrogen for the main-stem sites increased from 

about 0.9 milligram per liter for the Red River at Hickson, 

N. Dak., site to about 1.6 milligrams per liter for the Red River 

at Perley, Minn., site.

The Sheyenne River at Harwood, N. Dak., site had the 

largest estimated FWA concentration for total phosphorus (about 0.5 milligram per liter). The Otter Tail River above Breckenridge, Minn., site had the smallest concentration (about 0.1 milligram per liter). The estimated FWA concentrations for total phosphorus for the main-stem sites increased from about 0.15 milligram per liter for the Red River below Wahpeton, N. Dak., site to about 0.35 milligram per liter for the Red River 

at Perley, Minn., site.

The estimated FWA concentrations for suspended sediment for the main-stem sites increased from about 50 milli

li

f

h

d 

i

b

l

h

k

i

river is more difficult to identify because the pollutants may enter the river anywhere along its length. The nonpoint-source pollutants enter the river as dissolved constituents in ground water that is discharged to the river and as dissolved or suspended material in surface runoff (Tornes and others, 1997).

To control point- and nonpoint-source pollution in the Red 

River, the subbasins that contribute a disproportionate amount of pollutants to the river needed to be identified. Therefore, the U.S. Geological Survey (USGS), in cooperation with the North Dakota Department of Health, the Minnesota Pollution Control Agency, the Red River Joint Water Resource Board, and the Red River Watershed Management Board, began a study to collect and analyze water-quality data for the Red River. The data 

were used to determine the water-quality characteristics of the Red River and to determine which subbasins contribute the largest constituent loads to the river. Results of the study can be used by water-resource management agencies to establish sound water-quality standards.Purpose and Scope

The purpose of this report is to describe the water-quality 

characteristics of the upper Red River and to present estimated constituent loads and flow-weighted average (FWA) concentrations for the major subbasins of the upper Red River Basin. For this report

the upper Red River Basin is defined as the drainage 
d land cover, and physiographic areas in the Red River of the North Basin. [Modified

0 10 20 30 40 MILES

MINNESOTA 

OUTH DAKOTA

ANITOBA 

47 ̊

46 ̊

49 ̊

97 ̊

48 ̊

97 ̊ 96 ̊

95 ̊

95 ̊

96 ̊

INDEX MAP

B

C

D

RED 

RIVER

OF

THE

NORTH

RED RIVER OF THE

NORTH BASIN

FARGO Moorhead

East

Grand

Forks Grand

Forks

STUDY

AREA

1

2

3

4

6

5

7

8 9

11

10

Wahpeton

Wild Rice

Hickson

Harwood

West Fargo

Georgetown

Perley

Breckenridge

Doran

Thief

River

Falls

Detroit Lakes

White Rock

Fergus Falls

Crookston

NORTH DAKOTA

SOUTH DAKOTA

MINNESOTA

Elm

River

Rush

River

River

R.

Maple

River

Wild

Rice

 River

Goose

Antelope Cr.

Turtle

River

River

River

Park River

River

Forest

 Sand Hill

 River

Marsh River

Buffalo

River

River

Tail

River

Wild

Rice

Buffalo

S. Br.

River

Rabbit River

Mustinka

River

Otter

Sioux R.

Bois de

Two

Rivers

Grand

Marais

River

Upper Red Lake

Lower Red Lake

Red

River

Lake

Middle

River

Snake

River

River

Tamarac

North

Br.

South

River

Roseau

River

Clearwater

River

Lost

R.

Hill

Ruffy Br.

Br.

Burnham

Cr.

Mud River

River

Thief

Mud

Lake

Lake

Traverse

Spring Cr.

Stony Cr.

Whiskey Cr.

59500

eyenne River at

est Fargo, N. Dak.

0

er of the North

, N. Dak.

Introduction 3
Table 1. Water-quality sampling sites used in study.

Site

number

(see

figure 1)

Site

identification

number

Site name Period of data collection

Number of

samples

collected

during

1997-99

Approximate

contributing

drainage area

(square miles)

1 05046450 Otter Tail River above Breckenridge, Minn. 5-97 to 9-99 21 1,9702 05051300 Bois de Sioux River near Doran, Minn. 5-97 to 9-99 18 1,8803 05051505 Red River of the North at Highway 210 bridge at

Wahpeton, N. Dak.

5-97 to 11-97 6 3,940

4 05051510 Red River of the North below Wahpeton, N. Dak. 5-97 to 9-99 22 4,0005 05051522 Red River of the North at Hickson, N. Dak. 5-97 to 9-99 23 4,3006 05053600 Wild Rice River at Wild Rice, N. Dak. 5-97 to 9-97 5 1,7207 05053800 Red River of the North above Fargo, N. Dak. 5-97 to 9-99 24 6,8008 05054200 Red River of the North near Harwood, N. Dak. 5-97 to 9-99 22 6,9809 05060400 Sheyenne River at Harwood, N. Dak. 5-97 to 9-99 21 6,980

10 05062095 Buffalo River at U.S. Highway 75 in Georgetown,

Minn.

5-97 to 11-97 6 1,130

11 05062150 Red River of the North at Perley, Minn. 5-97 to 9-99 22 15,100

4 Constituent Loads and Flow-Weighted Average Concentrations for the Upper Red River of the North Basin, 1997-99
Basin. [Modified from Tornes and others, 1997.]

0 10 20 30 40 MILES

MINNESOTA 

OUTH DAKOTA

ANITOBA 

47 ̊

46 ̊

49 ̊

97 ̊

48 ̊

97 ̊ 96 ̊

95 ̊

95 ̊

96 ̊

RED 

RIVER

OF

THE

NORTH

FARGO Moorhead

East

Grand

Forks Grand

Forks

Wahpeton

Wild Rice

Hickson

Harwood

West Fargo

Georgetown

Perley

Breckenridge

Doran

Thief

River

Falls

Detroit Lakes

White Rock

Fergus Falls

Crookston

Elm

River

Rush

River

River

River

Maple

River

Wild

Rice

 River

Goose

Antelope Cr.

Turtle

River

River

River

Park River

River

Forest

 Sand Hill

 River

Marsh River

Buffalo

River

River

Tail

River

Wild

Rice

Buffalo

S. Br.

River

Rabbit River

Mustinka

River

Otter

Sioux R.

Bois de

Two

Rivers

Grand

Marais

River

Upper Red Lake

Lower Red Lake

Red

River

Lake

Middle

River

Snake

River

River

Tamarac

North

Br.

South

River

Roseau

River

Clearwater

River

Lost

R.

Hill

Ruffy Br.

Br.

Burnham

Cr.

Mud River

River

Thief

Mud

Lake

Lake

Traverse

Spring Cr.

Stony Cr.

Whiskey Cr.

20

22

24

24

26

24

22

20

20

Introduction 5
6 Constituent Loads and Flow-Weighted Average Concentrations for the Upper Red River of the North Basin, 1997-99

Streamflow in the Red River Basin varies greatly throughout the year. The largest streamflows usually occur in spring 

and early summer as a result of rain falling on melting snow or heavy rain falling on saturated soils. Flooding is a major problem and is aggravated by the gentle slope of the Red River and the flatness of the overbank areas. To facilitate agricultural production, an extensive system of drainage ditches has been constructed in parts of the Red River Valley Lake Plain and the Lake-Washed Till Plain to promote rapid surface drainage of clay-rich soils.

Ground water in the Red River Basin is primarily in sand 

and gravel aquifers near land surface or in buried glacial deposits throughout the basin. Ground water also moves toward the 

Red River through a regional system of bedrock and glacialdrift aquifers. Many of these bedrock and glacial-drift aquifers are connected hydraulically to streams in the basin and, therefore, affect the flow and water quality of the streams. During dry periods, ground water, in addition to water from lakes and reservoirs, is an important source of flow in many of the streams.

The fertile, black, fine-grained soils in the Red River Basin 

are conducive to cropland agriculture, which is the dominant land use in the basin. About 64 percent of the basin is comprised 

of cropland, and about 16 percent is comprised of pastureland, 

farmland, and local roads (data interpreted from U.S. Geologi

l S

1986

i

A

i

l

l S

i

i

S

i

Bismarck, N. Dak., to be analyzed for biochemical oxygen 

demand, major ions, nutrients, and trace elements. An additional water sample was collected from each site and sent to the 

USGS Sediment Laboratory in Iowa City, Iowa, to be analyzed for suspended-sediment concentration and particle-size distribution. Initially, water samples also were collected from two sites and sent to the North Dakota Department of Health Laboratory to be analyzed for pesticides. However, after the first year of the study, the pesticide sampling schedule was re-evaluated and, because of the large number of pesticide concentrations that were less than method detection limits, the sampling frequency for pesticides was reduced. The water-quality properties and constituents analyzed for in the study described in this report are given in table 2.

Water-quality data initially were collected at 11 sites 

(table 1, fig. 1), but, because of changes in resources available 

for the study, sampling was discontinued at one tributary site [site 6 (the Wild Rice River at Wild Rice, N. Dak.)] in September 1997 and at one main-stem site [site 3 (the Red River at 

Highway 210 bridge at Wahpeton, N. Dak.)] and one tributary 

site [site 10 (the Buffalo River at U.S. Highway 75 in Georgetown, Minn.)] in November 1997 (field measurements were 

continued at site 3). Sample-collection timelines for the 11 sites 

are shown in figure 3. The three discontinued sites were chosen 

because loads for those sites could be estimated using loads for existing main-stem sites. Therefore, the data for the three disTable 2. Water-quality properties and constituents for which water samples were analyzed.

Measured at

time of sample

collection

Determined at North Dakota

Department of Health Laboratory,

Bismarck, North Dakota

Determined at U.S. Geological

Survey Sediment Laboratory,

Iowa City, Iowa

Specific conductance Specific conductance Arsenic, total Suspended-sediment concentrationpH pH Barium, total Suspended sediment particle sizeAir temperature Biochemical oxygen demand, 5-day Beryllium, total recoverableWater temperature Calcium, dissolved Boron, total recoverableDissolved oxygen Magnesium, dissolved Cadmium, total recoverableBarometric pressure Sodium, dissolved Chromium, total recoverableFecal coliform Potassium, dissolved Copper, total recoverableFecal streptococci Alkalinity Iron, total recoverable

Sulfate, dissolved Lead, total recoverableChloride, dissolved Manganese, total recoverableNitrite plus nitrate, total Nickel, total recoverableAmmonia, total Selenium, totalAmmonia plus organic nitrogen, total Silver, total recoverable

Introduction 7
8 Constituent Loads and Flow-Weighted Average Concentrations for the Upper Red River of the North Basin, 1997-99

Site 1, Otter Tail River above Breckenridge, Minnesota

Site 2, Bois de Sioux River near Doran, Minnesota

Site 3, Red River at Highway 210 bridge at Wahpeton, North Dakota

Site 4, Red River below Wahpeton, North Dakota

Site 5, Red River at Hickson, North Dakota

Site 6, Wild Rice River at Wild Rice, North Dakota

Site 7, Red River above Fargo, North Dakota

Site 8, Red River near Harwood, North Dakota
Introduction 9

Load Computation

The actual annual load for a given river cross section, constituent, and water year1 is defined as the total mass of the constituent that is transported past the river cross section during the 

year. The actual annual load cannot be determined unless concentration is monitored continuously. Therefore, because concentration data were collected intermittently during this study, gaps in the data needed to be filled before the annual loads could be estimated. To fill the gaps, a relation between constituent concentration and streamflow was determined using the data collected during the study period (May 1997 through September 1999). Although constituent-concentration data were available before May 1997 for some sites, a common period of record was used for all sites to facilitate comparison of the loads. The relation was determined by a multiple regression model in which concentration was the dependent variable and streamflow was the primary explanatory variable. The regression model was determined using a program called Estimator (Cohn, Caulder, Gilroy, Zynjuk, and Summers, 1992; Cohn, Gilroy, and Baier, 1992). A seasonal factor was included in the regression model when needed.

After estimates of daily concentration were computed for 

each day of the year, the concentration was multiplied by daily 

streamflow to obtain an estimated daily load. The estimated daily loads then were summed to obtain the estimated annual 

water reduce nitrifying bacteria activities. Also, nitrogen and phosphorus concentrations may be larger during the summer than during other times of the year because of rainfall runoff 

from fields where fertilizers have been applied. Therefore, the ability to incorporate seasonality into the regression model was an important feature of Estimator.

The ability to include censored concentrations (that is, 

concentrations that are less than the laboratory method detection limit) in the regression model was another important feature of Estimator. If all concentrations used to fit the regression 

model were greater than the detection limit, minimum-variance unbiased estimates of daily concentration were computed using the fitted model described previously. However, if some concentrations were less than the detection limit, estimates of daily concentration were computed using an adjusted maximum likelihood estimation (AMLE) procedure (Cohn, Gilroy, and Baier, 1992). The AMLE procedure produced essentially unbiased estimates even when a large percentage (as much as 80 percent) 

of the concentrations used to fit the regression model were censored.

The instructions for using Estimator (G. Baier, T. Cohn, 

and E. Gilroy, U.S. Geological Survey, written commun., 1995) state that, for efficient load estimation, at least 25 samples should be collected per year for 2 years. However, the methodology also is valid for small sample sizes provided extra care is 

d 

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10 Constituent Loads and Flow-Weighted Average Concentrations for the Upper Red River of the North Basin, 1997-99

Water-Quality CharacteristicsBiochemical Oxygen Demand

A sufficient amount of dissolved oxygen is critical for 

maintaining the aquatic life and aesthetic quality of streams and lakes. Therefore, the determination of how organic matter affects the dissolved-oxygen concentration in a stream or lake is integral to water-quality management. The decay of organic matter in water is measured by the biochemical or chemical oxygen demand. The oxygen demand is a measure of the amount of oxygen removed from water by the metabolic requirements of oxidizable substances (Nemerow, 1974; Tchobanoglous and Schroeder, 1985).

The distribution of 5-day biochemical oxygen demand in 

the upper Red River Basin is shown in figure 4

19

(0)

16

(0)

6

(0)

20

(0)

21

(0)

5

(0)

19

(0)

21

(0)

20

(0)

6

(0)

20

(0)

67

20

 EXPLANATION

Site number given in table 1Number of values

. The oxygen 

demands were fairly small, and medians ranged from 1 to 3milligrams per liter. Site 2 (the Bois de Sioux River near Doran, 

Minn.) had the largest median oxygen demand.

Bacteria

Fecal indicator bacteria are used to assess the presence of 

waterborne disease-causing pathogens (pathogens). Indicator bacteria are used because they typically are not disease causing and they correlate well with several pathogens (Myers and Sylvester, 1997). The fecal indicator bacteria used in this study were fecal coliform and fecal streptococci. Both types of bacteria thrive in the intestines of warm-blooded animals and are 

present in waste from the animals. Therefore, the bacteria can 
Water-Quality Characteristics 11

be used to indicate if warm-blooded animals contribute to the contamination of a water body. The North Dakota and Minnesota water-quality standards for fecal coliform state that, for the recreational season of May 1 through September 30, the geometric mean of fecal coliform shall not exceed 200 colonies per 

100 milliliters based on a minimum of five samples within a 30-

day period (North Dakota Department of Health, 1991; Minnesota Pollution Control Agency, accessed July 17, 2002).

The distribution of fecal coliform in the upper Red River 

Basin is shown in figure 5

20

(0)

16

(0)

6

(0)

19

(0)

19

(0)

4

(0)

19

(0)

17

(0)

20

(0)

4

(0)

17

(0)

10,000

5,000

17

 EXPLANATION

Site number given in table 1N

b

f 

l

, and the distribution of fecal streptococci is shown in figure 6. The fecal coliform and fecal streptococci concentrations varied greatly from site to site. The largest 

median fecal coliform concentration was for site 9 (the Sheyenne River at Harwood, N. Dak.). Site 8 (the Red River near 

Harwood, N. Dak.), site 9, and site 11 (the Red River at Perley, 

Minn.) had the largest median fecal streptococci concentrations.

Fecal coliform samples were not collected with sufficient 

frequency to determine if the water-quality standards were met. However, more than 50 percent of the samples for site 9 and 

more than 25 percent of the samples for site 2 (the Bois de 

Sioux River near Doran, Minn.) and site 11 had fecal coliform 

concentrations that were greater than 200 colonies per 100

milliliters (fig. 5). Although a few of the samples that had large concentrations were not collected during the recreational season, the concentrations that were greater than 200 colonies per 

100 milliliters indicate an abundance of pathogens in the upper 

Red River Basin.

Dissolved Solids

Dissolved-solids concentrations in river water depend on 

the solubility of the rocks, the type of soil, and the amount of rainfall within a drainage basin. Large dissolved-solids concen-
20

(0)

15

(0)

6

(0)

19

(0)

19

(0)

4

(0)

19

(0)

17

(0)

20

(0)

3

(0)

17

(0)

10

50

500100

1,000

100,000

10,00050,000

5,000

COLONIES PER 100 MILLILITERS

20

(0)

 EXPLANATION

Site number given in table 1Number of valuesNumber of values at or belowdetection limitPercentile--Percentage of analysesequal to or less than indicatedvalues. Sites 3, 6, and 10 are notincluded in data comparisons.Maximum75th percentileMedian25th percentileMinimum

12 Constituent Loads and Flow-Weighted Average Concentrations for the Upper Red River of the North Basin, 1997-99
20

(0)

17

(0)

6

(0)

20

(0)

23

(0)

4

(0)

22

(0)

21

(0)

20

(0)

5

(0)

20

(0)

800600400200

1,2001,000

CONCENTRATION, IN MILLIGRAMS PER LITER

20

(0)

 EXPLANATION

Site number given in table 1Number of valuesNumber of values at or belowdetection limitPercentile--Percentage of analysesequal to or less than indicatedvalues. Sites 3, 6, and 10 are notincluded in data comparisons.Maximum75th percentileMedian25th percentileMinimum

Water-Quality Characteristics 13
White Rock Dam

Lake Traverse

River

River

Wild Rice

River

Otter

Tail

Bois de Sioux

Rabbit R.

RED

RIVER

OF

Wahpeton Breckenridge

NH4 NO3

DONNH4 NIT

NO3

GROUND

WATER

FPON DON

LPON NO3 POP

COPFPON

NO3PO4

WETLAND N2

NO3 DEN

NH4

NH4NO3PO4FPONBPP

P

LPON Biotic uptake of N and P

Sorption of Nand P to soils

Erosion and dissolutionof rocks and soil PIP CIP

PO4

NO3PO4

Resuspension ofnutrients fromstreambed sediments

SUBURBAN AREA

ATMOSPHERE

V

EXPLANATIONNutrientsNitrogenPhosphorusLarge particulate organic NFine particulate organic NDissolved organic NAmmoniaNitrateNitrogen gasParticulate inorganic PP

i

l

i

P

N

P

LPONFPON

DON

NH4NO3

N2

PIP

POP

M I N N E S O T A N O R T H D A K O T A

S O U T H D A K O T A N O R T H D A K O T A

NO3

NIT

DON

FPON

N

14 Constituent Loads and Flow-Weighted Average Concentrations for the Upper Red River of the North Basin, 1997-99
0 40 80 120 MILES

Base from U.S. Geological Survey

103 ̊ 101 ̊ 99 ̊ 97 ̊

95 ̊

93 ̊

91 ̊

49 ̊

47 ̊

45 ̊

43 ̊

43 ̊

45 ̊

47 ̊

49 ̊

91 ̊

95 ̊ 93 ̊

99 ̊ 101 ̊ 103 ̊

92 ̊

92 ̊

48 ̊

90 ̊

90 ̊

94 ̊

98 ̊ 96 ̊ 100 ̊ 102 ̊ 104 ̊

48 ̊

46 ̊

44 ̊

104 ̊ 102 ̊ 100 ̊

96 ̊ 94 ̊ 92 ̊

46 ̊

44 ̊

N O R T H D A K O T A

M I N N E S O T A

S O U T H D A K O T A

Lake

of the

Woods

Upper Red

Lake

Devils

 Lake

Mille

Lacs

Lake

Sakakawea

Lake Oahe

Lower Red

Lake

Lake

Red River of the North

Minnesota

River

River

Mississippi

Missouri

River

River

Missouri

James

River

Big

Sioux

River

Water-Quality Characteristics 15
20

(5)

17

(7)

6

(1)

22

(5)

21

(4)

5

(1)

21

(2)

22

(1)

21

(1)

6

(1)

21

(0)

0.50.1

0.05

10

51

CONCENTRATION, IN MILLIGRAMS PER LITER

21

(0)

 EXPLANATION

Site number given in table 1Number of valuesNumber of values at or belowdetection limitPercentile--Percentage of analysesequal to or less than indicatedvalues. Sites 3, 6, and 10 are notincluded in data comparisons.Maximum75th percentileMedian25th percentileMinimum

16 Constituent Loads and Flow-Weighted Average Concentrations for the Upper Red River of the North Basin, 1997-99
20

(15)

17

(7)

6

(3)

21

(6)

21

(12)

5

(4)

22

(11)

22

(2)

21

(6)

6

(3)

Detection limit

21

(3)

0.50.1

0.050.01

0.005

1

CONCENTRATION, IN MILLIGRAMS PER LITER

21

(3)

 EXPLANATION

Site number given in table 1Number of valuesNumber of values at or belowdetection limitPercentile--Percentage of analysesequal to or less than indicatedvalues. Sites 3, 6, and 10 are notincluded in data comparisons.Maximum75th percentileMedian25th percentileMinimum

Water-Quality Characteristics 17
20

(0)

17

(0)

6

(0)

21

(0)

21

(0)

4

(0)

21

(0)

21

(0)

21

(0)

5

(0)

21

(0)

0.40.60.81.21.41.61.8

1

CONCENTRATION, IN MILLIGRAMS PER LITER

21

(0)

 EXPLANATION

Site number given in table 1Number of valuesNumber of values at or belowdetection limitPercentile--Percentage of analysesequal to or less than indicatedvalues. Sites 3, 6, and 10 are notincluded in data comparisons.Maximum75th percentileMedian25th percentileMinimum

18 Constituent Loads and Flow-Weighted Average Concentrations for the Upper Red River of the North Basin, 1997-99
20

(0)

17

(0)

6

(0)

22

(0)

21

(0)

4

(0)

21

(0)

22

(0)

21

(0)

5

(0)

21

(0)

0.5

5

10

1

CONCENTRATION, IN MILLIGRAMS PER LITER

21

(0)

 EXPLANATION

Site number given in table 1Number of valuesNumber of values at or belowdetection limitPercentile--Percentage of analysesequal to or less than indicatedvalues. Sites 3, 6, and 10 are notincluded in data comparisons.Maximum75th percentileMedian25th percentileMinimum

Constituent Loads and Flow-Weighted Average Concentrations 19
20

(0)

17

(0)

6

(0)

21

(0)

20

(0)

5

(0)

23

(0)

22

(0)

21

(0)

6

(0)

21

(0)

0.20.30.40.10.50.60.7

CONCENTRATION, IN MILLIGRAMS PER LITER

21

(0)

 EXPLANATION

Site number given in table 1Number of valuesNumber of values at or belowdetection limitPercentile--Percentage of analysesequal to or less than indicatedvalues. Sites 3, 6, and 10 are notincluded in data comparisons.Maximum75th percentileMedian25th percentileMinimum

20 Constituent Loads and Flow-Weighted Average Concentrations for the Upper Red River of the North Basin, 1997-99
20

(5)

17

(1)

6

(1)

21

(2)

21

(4)

5

(0)

22

(1)

21

(1)

21

(0)

6

(0)

21

(1)

0.2

0.25

0.3

0.35

0.4

0.45

0.1

0.15

0.05

CONCENTRATION, IN MILLIGRAMS PER LITER

21

(1)

 EXPLANATION

Site number given in table 1Number of valuesNumber of values at or belowdetection limitPercentile--Percentage of analysesequal to or less than indicatedvalues. Sites 3, 6, and 10 are notincluded in data comparisons.Maximum75th percentileMedian25th percentileMinimum

Constituent Loads and Flow-Weighted Average Concentrations 21
21

(0)

29

(0)

6

(0)

21

(0)

21

(0)

5

(0)

22

(0)

21

(0)

21

(0)

6

(0)

22

(0)

100500

5010

5

1,000

CONCENTRATION, IN MILLIGRAMS PER LITER

22

(0)

 EXPLANATION

Site number given in table 1Number of valuesNumber of values at or belowdetection limitPercentile--Percentage of analysesequal to or less than indicatedvalues. Sites 3, 6, and 10 are notincluded in data comparisons.Maximum75th percentileMedian25th percentileMinimum

22 Constituent Loads and Flow-Weighted Average Concentrations for the Upper Red River of the North Basin, 1997-99
97 ̊00'

96 ̊30'

47 ̊00'

47 ̊00'

75

81

10

10

94

29

18

46

18

9

32

113

Creek

Creek

Whiskey

Creek

Stony

Deerhorn

Wolvert

River

River

River Lower

Rush R. Br.

River

River

River

RED

RIVER

OF

TH

River

Buffalo

Buffalo

Wild

Wild

South

Branch

Rice

Rice

Elm

 South Elm R.

Rush

Maple

South

Branch

Mapleton

West FARGO Moorhead

Fargo

Harwood

Horace

Wild Rice

Hickson

Barnesville

Georgetown

Perley

CASS CO.

CASS CO.

RICHLAND CO.

RANSOM CO.

CLAY CO.

CLAY CO. BECKER CO.

NORMAN CO.

WILKIN CO.

OTTER TAIL CO.

TRAILL CO.

11

10

9 8

7

6

5

Reach

R3

 subbasin

Reach R5 subbasin

Reach R5 subbasin

Reach R4 subbasin

Site 9 subbasin

Constituent Loads and Flow-Weighted Average Concentrations 23
1998 1999

Mean daily streamflow

75th percentile of historical mean daily streamflow

25th percentile of historical mean daily streamflow

Water-quality sample

M MJ J ASO ND A J FM MJ J AS A

ta, streamflow-gaging station for water years 1997, 1998, and 1999.

24 Constituent Loads and Flow-Weighted Average Concentrations for the Upper Red River of the North Basin, 1997-99
1998 1999

Mean daily streamflow

75th percentile of historical mean daily streamflow

25th percentile of historical mean daily streamflow

Water-quality sample

M MJ J ASO ND A J FM MJ J AS A

ta, streamflow-gaging station for water years 1997, 1998, and 1999.

Constituent Loads and Flow-Weighted Average Concentrations 25
Table 3. Annual streamflows and yields in the upper Red River of the North Basin for water years 1998 and 1999.

[--, indicates negative yield]

Site number or

intervening reach

designation

(see figure 17)

Site name and reach description Water year Streamflow (acre-feet)

Approximate

contributing

drainage area

(square miles)

Yield

(inches)

1 Otter Tail River above Breckenridge, Minn. 1998

1999

545,000661,000

1,970 5.2

6.3

2 Bois de Sioux River near Doran, Minn. 1998

1999

147,000165,000

1,880 1.5

1.6

R1 Intervening reach downstream from the Otter Tail

River above Breckenridge, Minn., and the Bois deSioux River near Doran, Minn., and upstream fromthe Red River of the North below Wahpeton, N. Dak.

19981999

-26,000-23,000

150 --

--

4 Red River of the North below Wahpeton, N. Dak. 1998

1999

666,000803,000

4,000 3.1

3.8

R2 Intervening reach downstream from the Red River of

the North below Wahpeton, N. Dak., and upstreamfrom the Red River of the North at Hickson, N. Dak.

19981999

92,00024,000

300 5.8

1.5

5 Red River of the North at Hickson, N. Dak. 1998

1999

758,000827,000

4,300 3.3

3.6

R3 Intervening reach downstream from the Red River of

1998

542,000

2,500 4.1

26 Constituent Loads and Flow-Weighted Average Concentrations for the Upper Red River of the North Basin, 1997-99
Constituent Loads and Flow-Weighted Average Concentrations 27

mated annual loads for the downstream primary sites to compute the estimated annual loads for the intervening reaches.

The degree of uncertainty in the estimated annual loads 

depends on the variability of the concentration data, the number of samples collected, and the ability of the multiple regression model to explain the variability of the concentration data given daily streamflow and seasonality. As indicated in tables 1–2 

through 1–9, the estimated annual loads for some constituentsite combinations are highly uncertain. For example, the estimation error (the difference between the estimated and actual 

annual loads) for total nitrite plus nitrate and ammonia may have exceeded 100 percent of the estimated annual load at most 

sites. The estimated annual loads for the intervening reaches are even more uncertain than the estimated annual loads for the primary sites because estimation errors for both the upstream and 

downstream primary sites contributed to the estimation errors for the intervening reaches. Therefore, to reduce uncertainty in the estimated annual loads, the loads for 1998 and 1999 were combined to obtain an estimated average annual load for 1998-99. The estimated average annual loads rather than the loads for the individual water years are given in tables 1–2 through 1–9 and discussed in this section.

Uncertainty is quantified in terms of the upper and lower 

90-percent confidence limits for the actual annual load. The confidence limits were computed as described in appendix 1 

d 

i

d 

i

i

1

For example, if the estimated annual load is 100 tons per year 

and the lower confidence limit is 90 tons per year, the actual 

annual load probably is large. However, if the estimated annual load is 100 tons per year but the lower confidence limit is 10 tons per year, the actual annual load may be small. Because the confidence limits for the primary sites could not be used to directly compute confidence limits for the intervening reaches, the confidence limits for the reaches were computed as described in appendix 1.

Basins that have large loads do not necessarily have poor 

water quality (as indicated by large constituent concentrations). Given two basins that have similar loads but different streamflows, the basin that has the higher streamflows will have more 

dilution and, therefore, smaller constituent concentrations than the basin that has the lower streamflows. Therefore, to compare the relative water quality of different subbasins, an estimated FWA concentration was computed by dividing the estimated average annual load for the subbasin by the average annual streamflow and then multiplying the quotient by an appropriate conversion factor. The estimated FWA concentration was computed using equation 2,

C

ˆ L

ˆ

Q--- ⎝ ⎠ ⎛ ⎞

= 735.3, (2)

where

ˆ
Figure 20. Estimated annual dissolved-solids loads and flow-weighted average concentrations for 1998-99 (loads not shown for

 EXPLANATION

Not available because of high uncertaintyMain-stem siteUpper 90-percent confidence limitEstimated valueLower 90-percent confidence limitTributary site or intervening reachUpper 90-percent confidence limitEstimated valueLower 90-percent confidence limit

-100

0

100200300400500600

LOAD, IN THOUSAND TONS PER YEAR

SITE NUMBER OR INTERVENING REACH DESIGNATION

FLOW-WEIGHTED AVERAGE CONCENTRATION,

IN MILLIGRAMS PER LITER

0

1 2 R1 4 R2 5 R3 7 R4 8 9 R5 11

100200300400500600700

NA

NA NA NA

28 Constituent Loads and Flow-Weighted Average Concentrations for the Upper Red River of the North Basin, 1997-99
LOAD, IN TONS PER YEAR

FLOW-WEIGHTED AVERAGE CONCENTRATION,

IN MILLIGRAMS PER LITER

Figure 21. Estimated annual total nitrite plus nitrate loads and flow-weighted average concentrations for 1998-99 (loads not

-400

0

400800

1,2001,6002,0002,400

SITE NUMBER OR INTERVENING REACH DESIGNATION

0

1 2 R1 4 R2 5 R3 7 R4 8 9 R5 11

0.40.81.21.6

2

2.42.8

NA NA NA

 EXPLANATION

Not available because of high uncertaintyMain-stem siteUpper 90-percent confidence limitEstimated valueLower 90-percent confidence limitTributary site or intervening reachUpper 90-percent confidence limitEstimated valueLower 90-percent confidence limit

NA

Constituent Loads and Flow-Weighted Average Concentrations 29
Figure 22. Estimated annual total ammonia loads and flow-weighted average concentrations for 1998-99 (loads not shown for

-100-200

0

100200300

LOAD, IN TONS PER YEAR

SITE NUMBER OR INTERVENING REACH DESIGNATION

FLOW-WEIGHTED AVERAGE CONCENTRATION,

IN MILLIGRAMS PER LITER

0

1 2 R1 4 R2 5 R3 7 R4 8 9 R5 11

0.10.20.30.40.50.6

NA NA NA

 EXPLANATION

Not available because of high uncertaintyMain-stem siteUpper 90-percent confidence limitEstimated valueLower 90-percent confidence limitTributary site or intervening reachUpper 90-percent confidence limitEstimated valueLower 90-percent confidence limit

NA

Estimated value -0.05

30 Constituent Loads and Flow-Weighted Average Concentrations for the Upper Red River of the North Basin, 1997-99
LOAD, IN TONS PER YEAR

FLOW-WEIGHTED AVERAGE CONCENTRATION,

IN MILLIGRAMS PER LITER

Figure 23. Estimated annual total organic nitrogen loads and flow-weighted average concentrations for 1998-99 (loads not

-200

0

400800600200

SITE NUMBER OR INTERVENING REACH DESIGNATION

0

1 2 R1 4 R2 5 R3 7 R4 8 9 R5 11

0.40.20.80.61.2

1

NA NA NA

 EXPLANATION

Not available because of high uncertaintyMain-stem siteUpper 90-percent confidence limitEstimated valueLower 90-percent confidence limitTributary site or intervening reachUpper 90-percent confidence limitEstimated valueLower 90-percent confidence limit

NA

Constituent Loads and Flow-Weighted Average Concentrations 31
Figure 24. Estimated annual total nitrogen loads and flow-weighted average concentrations for 1998-99 (loads not shown for

-400

0

400800

1,2001,6002,000

LOAD, IN TONS PER YEAR

SITE NUMBER OR INTERVENING REACH DESIGNATION

FLOW-WEIGHTED AVERAGE CONCENTRATION,

IN MILLIGRAMS PER LITER

01234

1 2 R1 4 R2 5 R3 7 R4 8 9 R5 11

NA NA NA

 EXPLANATION

Not available because of high uncertaintyMain-stem siteUpper 90-percent confidence limitEstimated valueLower 90-percent confidence limitTributary site or intervening reachUpper 90-percent confidence limitEstimated valueLower 90-percent confidence limit

NA

32 Constituent Loads and Flow-Weighted Average Concentrations for the Upper Red River of the North Basin, 1997-99
LOAD, IN TONS PER YEAR

FLOW-WEIGHTED AVERAGE CONCENTRATION,

IN MILLIGRAMS PER LITER

Figure 25. Estimated annual total phosphorus loads and flow-weighted average concentrations for 1998-99 (loads not shown for

-100

0

100200300400600500

SITE NUMBER OR INTERVENING REACH DESIGNATION

0

1 2 R1 4 R2 5 R3 7 R4 8 9 R5 11

0.40.20.80.6

1

NA NA NA

 EXPLANATION

Not available because of high uncertaintyMain-stem siteUpper 90-percent confidence limitEstimated valueLower 90-percent confidence limitTributary site or intervening reachUpper 90-percent confidence limitEstimated valueLower 90-percent confidence limit

NA

Constituent Loads and Flow-Weighted Average Concentrations 33
Figure 26. Estimated annual dissolved phosphorus loads and flow-weighted average concentrations for 1998-99 (loads not

-100

0

100200300400

LOAD, IN TONS PER YEAR

SITE NUMBER OR INTERVENING REACH DESIGNATION

FLOW-WEIGHTED AVERAGE CONCENTRATION,

IN MILLIGRAMS PER LITER

0

1 2 R1 4 R2 5 R3 7 R4 8 9 R5 11

0.10.20.30.40.50.60.7

NA NA NA

 EXPLANATION

Not available because of high uncertaintyMain-stem siteUpper 90-percent confidence limitEstimated valueLower 90-percent confidence limitTributary site or intervening reachUpper 90-percent confidence limitEstimated valueLower 90-percent confidence limit

NA

34 Constituent Loads and Flow-Weighted Average Concentrations for the Upper Red River of the North Basin, 1997-99
LOAD, IN THOUSAND TONS PER YEAR

FLOW-WEIGHTED AVERAGE CONCENTRATION,

IN MILLIGRAMS PER LITER

Figure 27. Estimated annual suspended-sediment loads and flow-weighted average concentrations for 1998-99 (loads not

-100

0

400300100200300400500600700200100

SITE NUMBER OR INTERVENING REACH DESIGNATION

0

1 2 R1 4 R2 5 R3 7 R4 8 9 R5 11

NA NA NA

 EXPLANATION

Not available because of high uncertaintyMain-stem siteUpper 90-percent confidence limitEstimated valueLower 90-percent confidence limitTributary site or intervening reachUpper 90-percent confidence limitEstimated valueLower 90-percent confidence limit

NA

Constituent Loads and Flow-Weighted Average Concentrations 35
36 Constituent Loads and Flow-Weighted Average Concentrations for the Upper Red River of the North Basin, 1997-99

year despite its small drainage area, but the estimate for that reach was highly uncertain.

The largest estimated FWA concentration for suspended 

sediment (about 340 milligrams per liter) for the tributary sites 

and intervening reaches was for reach R5 (fig. 27). Reach R3 

and site 9 had large estimated concentrations of about 280 and 

320 milligrams per liter, respectively. The estimated concentration for reach R5 was highly uncertain; confidence limits for 

that reach ranged from about 20 to 650 milligrams per liter. 

Sites 1 and 2 had small concentrations (less than 100 milligrams 

per liter). Although the concentration for reach R2 was not 

computed, the yield for that reach was much larger than the yields for the tributary sites. Therefore, a significant localized source of suspended sediment probably exists in reach R2. Similarly, the yield for reach R4 may have been much larger than 

the yields for the tributary sites.

The estimated FWA concentrations for suspended sediment for the main-stem sites increased from about 50 milligrams per liter for site 4 (the Red River below Wahpeton, 

N. Dak.) to about 300 milligrams per liter for site 11 (the Red 

River at Perley, Minn.) (fig. 27). Much of the increase occurred 

between site 4 and site 5 (the Red River at Hickson, N. Dak.) as 

a result of the large yield of suspended sediment from reach R2. 

The concentration between sites 4 and 5 increased from about 

50 milligrams per liter for site 4 to about 160 milligrams per 

li

f

i

5

h

i

i

d 

i

d

For dissolved solids, nutrients, and suspended sediment, a 

relation between constituent concentration and streamflow was determined using the data collected during the study period. The relation was determined by a multiple regression model in which concentration was the dependent variable and streamflow was the primary explanatory variable. The regression 

model was determined using a program called Estimator. Estimator was used to compute unbiased estimates of annual loads for each constituent and for each of eight primary water-quality 

sampling sites and to compute the degree of uncertainty associated with each estimated annual load. The estimated annual 

loads for the eight primary sites then were used to estimate annual loads for five intervening reaches in the study area. Results from Estimator were used as a screening tool to identify which subbasins contributed a disproportionate amount of pollutants to the Red River. To compare the relative water quality of the different subbasins, an estimated flow-weighted average (FWA) concentration was computed from the estimated average annual load and the average annual streamflow for each subbasin.

The 5-day biochemical oxygen demands in the upper Red 

River Basin were fairly small, and medians ranged from 1 to 3 milligrams per liter. The Bois de Sioux River near Doran, 

Minn., site had the largest median oxygen demand.

Fecal coliform samples were not collected with sufficient 

f

d

i

if 

h

h 

k

d 

i
Summary 37

River above Fargo, N. Dak., site. A small fraction of the nitrogen in the upper Red River Basin was in the ammonia form. The largest median total ammonia concentration was for the Red River near Harwood, N. Dak., site. The total ammonia concentration increased in a downstream direction from the Red River above Fargo, N. Dak., site to the Red River near Harwood, 

N. Dak., site, probably as a result of wastewater discharges 

from urban areas. The largest median total organic nitrogen concentration was for the Bois de Sioux River near Doran, Minn., site. The largest median total nitrogen concentration also was for the Bois de Sioux River near Doran, Minn., site. Generally, the median total nitrogen concentrations in the main stem 

Red River increased in a downstream direction.

Total and dissolved phosphorus concentrations also generally increased in a downstream direction. Nearly all median 

total phosphorus concentrations exceeded the North Dakota suggested guideline of 0.1 milligram per liter. The largest 

median total phosphorus concentrations were for the Bois de Sioux River near Doran, Minn., site, the Sheyenne River at Harwood, N. Dak., site, and the Red River at Perley, Minn., site. 

The largest median dissolved phosphorus concentration was for the Bois de Sioux River near Doran, Minn., site. Most of the dissolved phosphorus concentrations were greater than 0.1 milligram per liter, indicating an abundant natural source of phosphorus in the basin and/or significant nonpoint sources of 

phosphorus from human activities.

Red River above Fargo, N. Dak., intervening reach and the Red 

River near Harwood, N. Dak., to the Red River at Perley, Minn., 

intervening reach. The estimated FWA concentrations for total nitrite plus nitrate for the main-stem sites increased from about 0.2 milligram per liter for the Red River below Wahpeton, 

N. Dak., site to about 0.9 milligram per liter for the Red River 

at Perley, Minn., site. Much of the increase probably resulted from flows from the tributary sites and intervening reaches, excluding the Otter Tail River above Breckenridge, Minn., site. However, uncertainty in the estimated concentrations prevented any reliable conclusions regarding which sites or reaches contributed most to the increase.

The Red River above Fargo, N. Dak., to the Red River near 

Harwood, N. Dak., intervening reach had the largest estimated 

annual total ammonia load. The Sheyenne River at Harwood, N. Dak., site and the Bois de Sioux River near Doran, Minn., 

site also had large estimated loads. The estimated FWA concentrations for total ammonia for the main-stem sites increased 

from about 0.05 milligram per liter for the Red River above 

Fargo, N. Dak., site to about 0.15 milligram per liter for the Red 

River near Harwood, N. Dak., site. The increase resulted from 

a decrease in flows in the Red River above Fargo, N. Dak., to 

the Red River near Harwood, N. Dak., intervening reach and the 

large load for that reach. The FWA concentration decreased between the Red River near Harwood, N. Dak., site and the Red 

River at Perley, Minn., site, possibly because of the small con

i

f

h

d 

i

d

k

h

d 
38 Constituent Loads and Flow-Weighted Average Concentrations for the Upper Red River of the North Basin, 1997-99

That reach also had the largest estimated FWA concentration for total nitrogen (about 2.9 milligrams per liter), but the estimate was highly uncertain. The Otter Tail River above Breckenridge, Minn., site had the smallest concentration (about 0.6 milligram per liter). The estimated FWA concentrations for total nitrogen for the main-stem sites increased from about 0.9 milligram per liter for the Red River at Hickson, N. Dak., 

site to about 1.6 milligrams per liter for the Red River at Perley, 

Minn., site. Much of the increase probably resulted from the large concentrations for the Red River at Hickson, N. Dak., to 

the Red River above Fargo, N. Dak., intervening reach, the 

Sheyenne River at Harwood, N. Dak., site, and the Red River 

near Harwood, N. Dak., to the Red River at Perley, Minn., intervening reach.

The Sheyenne River at Harwood, N. Dak., site had the 

largest estimated annual total phosphorus load and the largest estimated FWA concentration (about 0.5 milligram per liter). 

The Otter Tail River above Breckenridge, Minn., site had the smallest estimated FWA concentration (about 0.1 milligram per 

liter). The Red River below Wahpeton, N. Dak., to the Red 

River at Hickson, N. Dak., intervening reach had a total phosphorus load of about 80 tons per year despite the small drainage 

area for that reach. The estimated FWA concentrations for total phosphorus for the main-stem sites increased from about 0.15 milligram per liter for the Red River below Wahpeton, N. Dak., 

site to about 0.35 milligram per liter for the Red River at Perley, 

i

i

f 

h

i

b

bl

l

d f

h

site as a result of the large suspended-sediment concentrations in the tributary flows and possibly a large yield of suspended sediment from the Red River above Fargo, N. Dak., to the Red 

River near Harwood, N. Dak., intervening reach.

ReferencesAntweiler, R.C., Goolsby, D.A., and Taylor, H.E., 1995, Nutrients in the Mississippi River, in Meade, R.H., ed., Contaminants in the Mississippi River, 1987-92: U.S. Geological 

Survey Circular 1133, p. 73-86.

Cohn, T., Caulder, D.L., Gilroy, E.J., Zynjuk, L.D., and Summers, R.M., 1992, The validity of a simple statistical model 

for estimating fluvial constituent loads--An empirical study involving nutrient loads entering Chesapeake Bay: Water Resources Research, v. 28, no. 9, p. 2353-2364.

Cohn, T., Gilroy, E.J., and Baier, W.G., 1992, Estimating fluvial transport of trace constituents using a regression model 

with data subject to censoring, in Proceedings of the Section on Statistics and the Environment: American Statistical Association, Boston, Mass., August 9-13, 1992, p. 142-151.

Guy, H.P., 1969, Laboratory theory and methods for sediment 

analysis: United States Geological Survey Techniques of Water-Resources Investigations

book 5

chap

C1

58 p
References 39

Tchobanoglous, G., and Schroeder, E.D., 1985, Water quality 

characteristics, modeling, modification: Menlo Park, Calif., Addison-Wesley Publishing Company, p. 107-121.

Tornes, L.H., and Brigham, M.E., 1994, Nutrients, suspended 

sediment, and pesticides in waters of the Red River of the North Basin, Minnesota, North Dakota, and South Dakota, 1970-90: U.S. Geological Survey Water-Resources Investigations Report 93-4231, 62 p.

Tornes, L.H., Brigham, M.E., and Lorenz, D.L., 1997, Nutrients, suspended sediment, and pesticides in streams in the 

Red River of the North Basin, Minnesota, North Dakota, and South Dakota, 1993-95: U.S. Geological Survey WaterResources Investigations Report 97-4053, 70 p.

U.S. Census Bureau, 2002a, Census '90: accessed May 9, 2002, 

at URL http://www.census.gov/main/www/cen1990.html

U.S. Census Bureau, 2002b, United States census 2000: 

accessed May 9, 2002, at URL http://www.census.gov/main/

www/cen2000.html

U.S. Department of Commerce, National Oceanic and Atmospheric Administration, Environmental Data Service, 1982, 

Monthly normals of temperature, precipitation, and heating and cooling degree days 1941-70 (Minnesota, North Dakota, and South Dakota): Asheville, North Carolina, Climatography of the United States, No. 81.

U.S. Geological Survey, 1986, Land use and land cover digital 

data from 1:250,000- and 1:100,000-scale maps: National Mapping Program Technical Instructions Data Users Guide 4, 36 p.

Wilde, F.D., Radtke, D.B., Gibs, J., and Iwatsubo, R.T., 1999, 

Collection of water samples: U.S. Geological Survey Techniques of Water-Resources Investigations, book 9, chap. A4, p. 7-103.
40 Constituent Loads and Flow-Weighted Average Concentrations for the Upper Red River of the North Basin, 1997-99
Appendix 1. Regression Models for Daily Concentration and Uncertainty in Estimated Annual Loads 41

Appendix 1. Regression Models for Daily Concentration and Uncertainty in Estimated 

Annual Loads

Results of the regression analysis for historical constituent 

concentrations and daily loads for eight water-quality sampling sites used in this study are given in table 1–1. The estimated 

annual loads computed for this study depended on the relation between concentration and streamflow and on seasonality in concentration. The more variability in concentration that could be explained by streamflow and seasonality, the more accurate the estimated annual load. The natural logarithm of concentration was the dependent variable in the regression model, and the 

natural logarithm of daily streamflow was the explanatory variable. The explanatory variable was included whether or not the coefficient for streamflow was statistically significant. The seasonal terms (the sine and cosine variables) for 6 months and for 1 year were included only if one of the terms was significant at the 10-percent level or higher. Significant seasonality in concentration occurred for most variables and most sites.

Estimated annual loads for each constituent for water years 

1998 and 1999 are given in tables 1–2 through 1–9. The Estimator program was used to compute unbiased estimates of the 

The standard errors of the estimated annual loads for each 

water year were computed with the Estimator program. The standard errors then were used to compute approximate confidence limits for the actual annual loads using equation 1–1:

Prob L L

ˆ

ZPSE L

ˆ

[ ] > – ( )

Prob L L

ˆ

ZPSE L

ˆ

= = [ ] < + ( ) P

(1–1)

where

Prob denotes probability;

L is the actual annual load, in tons per year;L

ˆ

is the estimated annual load, in tons per year;

ZP is the pth percentile of a standard normal

distribution;

SE L

ˆ

( ) is the standard error of the estimated annual

load; and

P is a specified confidence limit.
L

ˆ

1998-99

12-- L

ˆ

1998

L

ˆ

1999

= ( ) +

42 Constituent Loads and Flow-Weighted Average Concentrations for the Upper Red River of the North Basin, 1997-99

(1–4)

where

L

ˆ

1998-99 is the estimated average annual load, in tons

per year, for 1998-99;

L

ˆ

1998 is the estimated annual load, in tons per year,

for 1998; and

L

ˆ

1999 is the estimated annual load, in tons per year,

for 1999;

was used to obtain an estimated average annual load for 1998-99. Assuming the estimated annual loads for water years 1998 and 1999 were statistically independent, the standard error of the estimated average annual load was defined by equation 1–5:

SE Lˆ 1998-99 ( ) 1

2-- SE Lˆ 1998 [ ] ( ) 2 SE Lˆ 1999 [ ] ( ) 2 =

+ . (1–5)

Therefore, in accordance with equation 1–3, the uncertainty of 

the estimated average annual load was given by equation 1–6:

U Lˆ 1998-99 ( ) 1.285SE Lˆ 1998-99 ( )

L

ˆ

1998-99

= ------------------------------------------- x 100. (1–6)

Estimated annual loads for intervening reaches were 

obtained by subtracting estimated annual load(s) for upstream 

Var 

L

ˆ

R ( )

Var 

L

ˆ

DS ( ) Var 

L

ˆ

US ( ) 2Cov 

L

ˆ

DS

L

ˆ

US

=

+

– ( ) ,

(1–8)

where

Var ( ) X denotes the variance of the random variable

X , and

Cov ( ) X Y, denotes the covariance of the random variables

X and 

Y .

The variance could not be computed without the covariance term. However, the variance could be bounded by two extreme cases. Because the estimated annual loads for the upstream and downstream sites probably would not have a negative covariance, the largest variance was obtained by assuming the 

Cov 

L

ˆ

DS

L

ˆ

US ( ) , was equal to zero. Therefore, the upper bound 

was given by equation 1–9:

Var 

L

ˆ

R ( ) Var 

L

ˆ

DS ( ) Var 

L

ˆ

US

≤

+ ( ). (1–9)

The lower bound for the variance was obtained by assuming the estimated annual load for the downstream site was equal to the estimated annual load for the upstream site plus an independent incremental load, 

L

ˆ

DS

L

ˆ

US ( ) =

+

X where the Cov 

L

ˆ

US ( ) , 

X

was equal to zero. Therefore, the lower bound was given by equation 1–10:
Appendix 1. Regression Models for Daily Concentration and Uncertainty in Estimated Annual Loads 43

Table 1–1. Results of regression analysis for historical constituent concentrations and daily loads.[LF, natural logarithm of daily streamflow; S1, sine function with a period of 1 year; C1, cosine function with a period of 1 year; S2, sine function with a period 

of 6 months; C2, cosine function with a period of 6 months]

Site

number Site name

Number of

 values

used in

analysis

Explanatory variables

included in regression

model for natural

logarithm of

concentration

and daily load

Standard

error of

regression

Coefficient of

variation (R2)

for natural

logarithm of

concentration

(percent)

Coefficient of

variation (R2)

for natural

logarithm of

daily load

(percent)

Dissolved solids

1 Otter Tail River above

Breckenridge, Minn.

20 LF 0.11 4 82

2 Bois de Sioux River near

Doran, Minn.

17 LF, S2, C2 .22 53 99

4 Red River of the North below

Wahpeton, N. Dak.

20 LF, S1, C1 .26 35 86

5 Red River of the North at

Hickson, N. Dak.

23 LF .23 1 91

7 Red River of the North above

Fargo, N. Dak.

22 LF, S2, C2 .24 10 94

8 Red River of the North near

Harwood, N. Dak.

21 LF, S2, C2 .16 34 96
44 Constituent Loads and Flow-Weighted Average Concentrations for the Upper Red River of the North Basin, 1997-99

Ammonia, total

1 Otter Tail River above

Breckenridge, Minn.

20 LF, S1, C1, S2, C2 1.39 56 56

2 Bois de Sioux River near

Doran, Minn.

17 LF 1.81 42 81

4 Red River of the North below

Wahpeton, N. Dak.

21 LF, S1, C1 1.30 13 20

5 Red River of the North at

Hickson, N. Dak.

21 LF, S1, C1, S2, C2 1.54 33 44

7 Red River of the North above

Fargo, N. Dak.

22 LF, S1, C1 1.25 37 58

8 Red River of the North near

Harwood, N. Dak.

22 LF, S1, C1 .89 29 42

Table 1–1. Results of regression analysis for historical constituent concentrations and daily loads.—Continued[LF, natural logarithm of daily streamflow; S1, sine function with a period of 1 year; C1, cosine function with a period of 1 year; S2, sine function with a period 

of 6 months; C2, cosine function with a period of 6 months]

Site

number Site name

Number of

 values

used in

analysis

Explanatory variables

included in regression

model for natural

logarithm of

concentration

and daily load

Standard

error of

regression

Coefficient of

variation (R2)

for natural

logarithm of

concentration

(percent)

Coefficient of

variation (R2)

for natural

logarithm of

daily load

(percent)
Appendix 1. Regression Models for Daily Concentration and Uncertainty in Estimated Annual Loads 45

Nitrogen, total

1 Otter Tail River above

Breckenridge, Minn.

20 LF, S1, C1, S2, C2 0.30 29 52

2 Bois de Sioux River near

Doran, Minn.

17 LF, S2, C2 .56 1 95

4 Red River of the North below

Wahpeton, N. Dak.

22 LF, S2, C2 .42 13 71

5 Red River of the North at

Hickson, N. Dak.

21 LF, S2, C2 .55 12 68

7 Red River of the North above

Fargo, N. Dak.

21 LF, S1, C1 .33 63 95

8 Red River of the North near

Harwood, N. Dak.

22 LF, S2, C2 .32 2 82

Table 1–1. Results of regression analysis for historical constituent concentrations and daily loads.—Continued[LF, natural logarithm of daily streamflow; S1, sine function with a period of 1 year; C1, cosine function with a period of 1 year; S2, sine function with a period 

of 6 months; C2, cosine function with a period of 6 months]

Site

number Site name

Number of

 values

used in

analysis

Explanatory variables

included in regression

model for natural

logarithm of

concentration

and daily load

Standard

error of

regression

Coefficient of

variation (R2)

for natural

logarithm of

concentration

(percent)

Coefficient of

variation (R2)

for natural

logarithm of

daily load

(percent)
46 Constituent Loads and Flow-Weighted Average Concentrations for the Upper Red River of the North Basin, 1997-99

Phosphorus, dissolved

1 Otter Tail River above

Breckenridge, Minn.

20 LF, S1, C1, S2, C2 0.71 49 46

2 Bois de Sioux River near

Doran, Minn.

17 LF, S2, C2 .92 36 87

4 Red River of the North below

Wahpeton, N. Dak.

21 LF, S2, C2 .84 14 26

5 Red River of the North at

Hickson, N. Dak.

21 LF, S1, C1 1.25 2 22

7 Red River of the North above

Fargo, N. Dak.

22 LF, S1, C1, S2, C2 .88 43 81

8 Red River of the North near

Harwood, N. Dak.

21 LF, S1, C1 .71 19 46

Table 1–1. Results of regression analysis for historical constituent concentrations and daily loads.—Continued[LF, natural logarithm of daily streamflow; S1, sine function with a period of 1 year; C1, cosine function with a period of 1 year; S2, sine function with a period 

of 6 months; C2, cosine function with a period of 6 months]

Site

number Site name

Number of

 values

used in

analysis

Explanatory variables

included in regression

model for natural

logarithm of

concentration

and daily load

Standard

error of

regression

Coefficient of

variation (R2)

for natural

logarithm of

concentration

(percent)

Coefficient of

variation (R2)

for natural

logarithm of

daily load

(percent)
Appendix 1. Regression Models for Daily Concentration and Uncertainty in Estimated Annual Loads 47

Table 1–2. Estimated annual dissolved-solids loads and flow-weighted average concentrations for the upper Red Riverof the North Basin.

Site number or

intervening

reach

designation

Site name or intervening

reach designation

Water

year

Load

(thousand

tons per

year)1

Uncertainty

(percent)1

Flow-weighted

average

concentration

(milligrams

per liter)

1 Otter Tail River above Breckenridge, Minn. 1998

1999

1998-99

177212195

1010

7

239235237

2 Bois de Sioux River near Doran, Minn. 1998

1999

1998-99

123143133

141310

612639626

R1 Intervening reach downstream from the Otter Tail

River above Breckenridge, Minn., and the Boisde Sioux River near Doran, Minn., and upstreamfrom the Red River of the North below Wahpeton,N. Dak.

19981999

1998-99

175737

----

89

------

4 Red River of the North below Wahpeton, N. Dak. 1998

1999

1998-99

316412364

1213

9

349378365

R2 Intervening reach downstream from the Red River of

the North below Wahpeton, N. Dak., and upstream

19981999

9

-57

----

----
48 Constituent Loads and Flow-Weighted Average Concentrations for the Upper Red River of the North Basin, 1997-99

11 Red River of the North at Perley, Minn. 1998

1999

1998-99

1,3891,4611,425

10

97

458463461

1Because of rounding, the numbers given for 1998-99 may not equal the average of the numbers given for water years 1998 and 1999.

Table 1–2. Estimated annual dissolved-solids loads and flow-weighted average concentrations for the upper Red River

of the North Basin.—Continued

Site number or

intervening

reach

designation

Site name or intervening

reach designation

Water

year

Load

(thousand

tons per

year)1

Uncertainty

(percent)1

Flow-weighted

average

concentration

(milligrams

per liter)
Appendix 1. Regression Models for Daily Concentration and Uncertainty in Estimated Annual Loads 49

Table 1–3. Estimated annual total nitrite plus nitrate loads and flow-weighted average concentrations for the upper Red Riverof the North Basin.

Site number or

intervening

reach

designation

Site name or intervening

reach designation

Water

year

Load

(tons per

year)1

Uncertainty

(percent)1

Flow-weighted

average

concentration

(milligrams

per liter)

1 Otter Tail River above Breckenridge, Minn. 1998

1999

1998-99

526458

635541

0.07

.07.07

2 Bois de Sioux River near Doran, Minn. 1998

1999

1998-99

179176178

283274196

.89.79.84

R1 Intervening reach downstream from the Otter Tail

River above Breckenridge, Minn., and the Boisde Sioux River near Doran, Minn., and upstreamfrom the Red River of the North below Wahpeton,N. Dak.

19981999

1998-99

-61-35-48

----

238

------

4 Red River of the North below Wahpeton, N. Dak. 1998

1999

1998-99

170205187

928261

.19.19.19

R2 Intervening reach downstream from the Red River of

the North below Wahpeton, N. Dak., and upstream

19981999

112109

----

----
50 Constituent Loads and Flow-Weighted Average Concentrations for the Upper Red River of the North Basin, 1997-99

11 Red River of the North at Perley, Minn. 1998

1999

1998-99

2,8552,9122,884

534836

0.94

.92.93

1Because of rounding, the numbers given for 1998-99 may not equal the average of the numbers given for water years 1998 and 1999.

Table 1–3. Estimated annual total nitrite plus nitrate loads and flow-weighted average concentrations for the upper Red River

of the North Basin.—Continued

Site number or

intervening

reach

designation

Site name or intervening

reach designation

Water

year

Load

(tons per

year)1

Uncertainty

(percent)1

Flow-weighted

average

concentration

(milligrams

per liter)
Appendix 1. Regression Models for Daily Concentration and Uncertainty in Estimated Annual Loads 51

Table 1–4. Estimated annual total ammonia loads and flow-weighted average concentrations for the upper Red Riverof the North Basin.

Site number or

intervening

reach

designation

Site name or intervening

reach designation

Water

year

Load

(tons per

year)1

Uncertainty

(percent)1

Flow-weighted

average

concentration

(milligrams

per liter)

1 Otter Tail River above Breckenridge, Minn. 1998

1999

1998-99

352128

153120106

0.05

.02.03

2 Bois de Sioux River near Doran, Minn. 1998

1999

1998-99

686667

198187136

.34.29.32

R1 Intervening reach downstream from the Otter Tail

River above Breckenridge, Minn., and the Boisde Sioux River near Doran, Minn., and upstreamfrom the Red River of the North below Wahpeton,N. Dak.

19981999

1998-99

-45-25-35

----

101

------

4 Red River of the North below Wahpeton, N. Dak. 1998

1999

1998-99

586260

848359

.06.06.06

R2 Intervening reach downstream from the Red River of

the North below Wahpeton, N. Dak., and upstream

19981999

-15-14

----

----
52 Constituent Loads and Flow-Weighted Average Concentrations for the Upper Red River of the North Basin, 1997-99

11 Red River of the North at Perley, Minn. 1998

1999

1998-99

364377371

787253

0.12

.12.12

1Because of rounding, the numbers given for 1998-99 may not equal the average of the numbers given for water years 1998 and 1999.

Table 1–4. Estimated annual total ammonia loads and flow-weighted average concentrations for the upper Red River

of the North Basin.—Continued

Site number or

intervening

reach

designation

Site name or intervening

reach designation

Water

year

Load

(tons per

year)1

Uncertainty

(percent)1

Flow-weighted

average

concentration

(milligrams

per liter)
Appendix 1. Regression Models for Daily Concentration and Uncertainty in Estimated Annual Loads 53

Table 1–5. Estimated annual total organic nitrogen loads and flow-weighted average concentrations for the upper Red Riverof the North Basin.

Site number or

intervening

reach

designation

Site name or intervening

reach designation

Water

year

Load

(tons per

year)1

Uncertainty

(percent)1

Flow-weighted

average

concentration

(milligrams

per liter)

1 Otter Tail River above Breckenridge, Minn. 1998

1999

1998-99

379444412

1412

9

0.51

.49.50

2 Bois de Sioux River near Doran, Minn. 1998

1999

1998-99

182209196

161411

.91.93.92

R1 Intervening reach downstream from the Otter Tail

River above Breckenridge, Minn., and the Boisde Sioux River near Doran, Minn., and upstreamfrom the Red River of the North below Wahpeton,N. Dak.

19981999

1998-99

267350

----

132

------

4 Red River of the North below Wahpeton, N. Dak. 1998

1999

1998-99

588727657

131410

.65.66.66

R2 Intervening reach downstream from the Red River of

the North below Wahpeton, N. Dak., and upstream

19981999

-2

-77

----

----
54 Constituent Loads and Flow-Weighted Average Concentrations for the Upper Red River of the North Basin, 1997-99

11 Red River of the North at Perley, Minn. 1998

1999

1998-99

2,0092,1182,063

1211

8

0.66

.67.67

1Because of rounding, the numbers given for 1998-99 may not equal the average of the numbers given for water years 1998 and 1999.

Table 1–5. Estimated annual total organic nitrogen loads and flow-weighted average concentrations for the upper Red River

of the North Basin.—Continued

Site number or

intervening

reach

designation

Site name or intervening

reach designation

Water

year

Load

(tons per

year)1

Uncertainty

(percent)1

Flow-weighted

average

concentration

(milligrams

per liter)
Appendix 1. Regression Models for Daily Concentration and Uncertainty in Estimated Annual Loads 55

Table 1–6. Estimated annual total nitrogen loads and flow-weighted average concentrations for the upper Red Riverof the North Basin.

Site number or

intervening

reach

designation

Site name or intervening

reach designation

Water

year

Load

(tons per

year)1

Uncertainty

(percent)1

Flow-weighted

average

concentration

(milligrams

per liter)

1 Otter Tail River above Breckenridge, Minn. 1998

1999

1998-99

473530502

161310

0.64

.59.61

2 Bois de Sioux River near Doran, Minn. 1998

1999

1998-99

310348330

393526

1.561.551.55

R1 Intervening reach downstream from the Otter Tail

River above Breckenridge, Minn., and the Boisde Sioux River near Doran, Minn., and upstreamfrom the Red River of the North below Wahpeton,N. Dak.

19981999

1998-99

32

142

87

----

148

------

4 Red River of the North below Wahpeton, N. Dak. 1998

1999

1998-99

816

1,021

918

192014

.90.93.92

R2 Intervening reach downstream from the Red River of

the North below Wahpeton, N. Dak., and upstream

19981999

101

-40

----

----
56 Constituent Loads and Flow-Weighted Average Concentrations for the Upper Red River of the North Basin, 1997-99

11 Red River of the North at Perley, Minn. 1998

1999

1998-99

4,9225,1705,045

272418

1.621.641.63

1Because of rounding, the numbers given for 1998-99 may not equal the average of the numbers given for water years 1998 and 1999.

Table 1–6. Estimated annual total nitrogen loads and flow-weighted average concentrations for the upper Red River

of the North Basin.—Continued

Site number or

intervening

reach

designation

Site name or intervening

reach designation

Water

year

Load

(tons per

year)1

Uncertainty

(percent)1

Flow-weighted

average

concentration

(milligrams

per liter)
Appendix 1. Regression Models for Daily Concentration and Uncertainty in Estimated Annual Loads 57

Table 1–7. Estimated annual total phosphorus loads and flow-weighted average concentrations for the upper Red Riverof the North Basin.

Site number or

intervening

reach

designation

Site name or intervening

reach designation

Water

year

Load

(tons per

year)1

Uncertainty

(percent)1

Flow-weighted

average

concentration

(milligrams

per liter)

1 Otter Tail River above Breckenridge, Minn. 1998

1999

1998-99

110109109

645843

0.15

.12.13

2 Bois de Sioux River near Doran, Minn. 1998

1999

1998-99

425951

404028

.21.27.24

R1 Intervening reach downstream from the Otter Tail

River above Breckenridge, Minn., and the Boisde Sioux River near Doran, Minn., and upstreamfrom the Red River of the North below Wahpeton,N. Dak.

19981999

1998-99

-15

-7

-16

----

28

------

4 Red River of the North below Wahpeton, N. Dak. 1998

1999

1998-99

127161144

181913

.14.15.14

R2 Intervening reach downstream from the Red River of

the North below Wahpeton, N. Dak., and upstream

19981999

9177

----

----
58 Constituent Loads and Flow-Weighted Average Concentrations for the Upper Red River of the North Basin, 1997-99

11 Red River of the North at Perley, Minn. 1998

1999

1998-99

1,1021,1691,135

434130

0.36

.37.37

1Because of rounding, the numbers given for 1998-99 may not equal the average of the numbers given for water years 1998 and 1999.

Table 1–7. Estimated annual total phosphorus loads and flow-weighted average concentrations for the upper Red River

of the North Basin.—Continued

Site number or

intervening

reach

designation

Site name or intervening

reach designation

Water

year

Load

(tons per

year)1

Uncertainty

(percent)1

Flow-weighted

average

concentration

(milligrams

per liter)
Appendix 1. Regression Models for Daily Concentration and Uncertainty in Estimated Annual Loads 59

Table 1–8. Estimated annual dissolved phosphorus loads and flow-weighted average concentrations for the upper Red Riverof the North Basin.

Site number or

intervening

reach

designation

Site name or intervening

reach designation

Water

year

Load

(tons per

year)1

Uncertainty

(percent)1

Flow-weighted

average

concentration

(milligrams

per liter)

1 Otter Tail River above Breckenridge, Minn. 1998

1999

1998-99

202322

343323

0.03

.03.03

2 Bois de Sioux River near Doran, Minn. 1998

1999

1998-99

505452

766750

.25.24.24

R1 Intervening reach downstream from the Otter Tail

River above Breckenridge, Minn., and the Boisde Sioux River near Doran, Minn., and upstreamfrom the Red River of the North below Wahpeton,N. Dak.

19981999

1998-99

192623

----

129

------

4 Red River of the North below Wahpeton, N. Dak. 1998

1999

1998-99

88

104

96

424431

.10.09.10

R2 Intervening reach downstream from the Red River of

the North below Wahpeton, N. Dak., and upstream

19981999

2931

----

----
60 Constituent Loads and Flow-Weighted Average Concentrations for the Upper Red River of the North Basin, 1997-99

11 Red River of the North at Perley, Minn. 1998

1999

1998-99

618700659

484834

0.20

.22.21

1Because of rounding, the numbers given for 1998-99 may not equal the average of the numbers given for water years 1998 and 1999.

Table 1–8. Estimated annual dissolved phosphorus loads and flow-weighted average concentrations for the upper Red River

of the North Basin.—Continued

Site number or

intervening

reach

designation

Site name or intervening

reach designation

Water

year

Load

(tons per

year)1

Uncertainty

(percent)1

Flow-weighted

average

concentration

(milligrams

per liter)
Appendix 1. Regression Models for Daily Concentration and Uncertainty in Estimated Annual Loads 61

Table 1–9. Estimated annual suspended-sediment loads and flow-weighted average concentrations for the upper Red Riverof the North Basin.

Site number or

intervening

reach

designation

Site name or intervening

reach designation

Water

year

Load

(thousand

tons per

year)1

Uncertainty

(percent)1

Flow-weighted

average

concentration

(milligrams

per liter)

1 Otter Tail River above Breckenridge, Minn. 1998

1999

1998-99

494547

231513

665057

2 Bois de Sioux River near Doran, Minn. 1998

1999

1998-99

162018

454833

828985

R1 Intervening reach downstream from the Otter Tail

River above Breckenridge, Minn., and the Boisde Sioux River near Doran, Minn., and upstreamfrom the Red River of the North below Wahpeton,N. Dak.

19981999

1998-99

-15

-3-9

----

101

------

4 Red River of the North below Wahpeton, N. Dak. 1998

1999

1998-99

506156

242517

555656

R2 Intervening reach downstream from the Red River of

the North below Wahpeton, N. Dak., and upstream

19981999

119118

----

----
62 Constituent Loads and Flow-Weighted Average Concentrations for the Upper Red River of the North Basin, 1997-99

11 Red River of the North at Perley, Minn. 1998

1999

1998-99

968778873

423226

319247282

1Because of rounding, the numbers given for 1998-99 may not equal the average of the numbers given for water years 1998 and 1999.

Table 1–9. Estimated annual suspended-sediment loads and flow-weighted average concentrations for the upper Red River

of the North Basin.—Continued

Site number or

intervening

reach

designation

Site name or intervening

reach designation

Water

year

Load

(thousand

tons per

year)1

Uncertainty

(percent)1

Flow-weighted

average

concentration

(milligrams

per liter)