U.S. Department of the Interior

U.S. Geological Survey

Scientific Investigations Report 2014–5212

In cooperation with North Dakota State University Agriculture Research Extension

Water-Quality Characteristics in Runoff for Three Discovery 

Farms in North Dakota, 2008–12

U1

U2

U3 #D1

D3

Baldhill Creek

# D2

#

#

E3

E1 E2

 Lake

Ashtabula

CASS COUNTY

BARNES

COUNTY

NORTH DAKOTA

MCLEAN COUNTY

Missouri River

River

Maple

River

Underwood

Turtle Lake

Bismarck

Leonard

Underwood Farm

Dazey

Farm

Sheyenne

Embden

BaldhillCreek

Embden Farm

Dazey

Underwood Farm Dazey Farm Embden Farm

Water-Quality Characteristics in Runoff for 

Three Discovery Farms in North Dakota, 

2008–12

By Rochelle A. Nustad, Kathleen M. Rowland, and Ronald G.Wiederholt

In cooperation with North Dakota State University Agriculture Research Extension

Scientific Investigations Report 2014–5212

U.S. Department of the Interior

U.S. Geological Survey
U.S. Department of the Interior

SALLY JEWELL, Secretary

U.S. Geological Survey

Suzette M. Kimball, Acting Director

U.S. Geological Survey, Reston, Virginia: 2015

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Although this information product, for the most part, is in the public domain, it also may contain copyrighted materials 

as noted in the text. Permission to reproduce copyrighted items must be secured from the copyright owner.

Suggested citation:

Nustad, R.A., Rowland, K.M., and Wiederholt, R.G., 2015, Water-quality characteristics in runoff for three discovery 

farms in North Dakota, 2008–12: U.S. Geological Survey Scientific Investigations Report 2014–5212, 31 p., http://

dx.doi.org/10.3133/sir20145212.

ISSN 2328-0328 (online)
iii

Contents

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

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

Purpose and Scope .......................................................................................................................................2

Descriptions of the Discovery Farms in North Dakota ............................................................................3

Underwood Farm...................................................................................................................................3

Dazey Farm.............................................................................................................................................3

Embden Farm.........................................................................................................................................3

Methods...........................................................................................................................................................6

Data Collection....................................................................................................................................10

Data Presentation and Analysis.......................................................................................................11

Quality Assurance and Quality Control ....................................................................................................11

Precipitation, Flow Volume, and Runoff...................................................................................................12

Annual Precipitation, Flow Volume, and Runoff ............................................................................12

Monthly Precipitation and Runoff ....................................................................................................15

Water-Quality Characteristics ...................................................................................................................15

Water Quality by Farm........................................................................................................................15

Underwood Farm........................................................................................................................15

Dazey Farm..................................................................................................................................21

Embden Farm..............................................................................................................................21

Summary........................................................................................................................................................28

References Cited..........................................................................................................................................30

Figures

1. Map showing location of Discovery Farms in North Dakota ................................................4

2. Photographs showing equipment installed at Discovery Farms sites in North Dakota ...6

3. Map showing location of monitoring sites and aerial view of Underwood Farm in

North Dakota .................................................................................................................................7

4. Map showing location of monitoring sites and aerial view of Dazey Farm in North

Dakota.............................................................................................................................................8

5. Map showing location of monitoring sites and aerial view of Embden Farm in

North Dakota .................................................................................................................................9

6. Graphs showing annual precipitation for Discovery Farms in North Dakota from

March through October and 30-year mean annual precipitation; the 30-year

mean annual is an average of National Weather Service sites located near the

Underwood, Dazey, and Embden Farms from March through October ............................12

7. Graphs showing flow volume for Discovery Farms in North Dakota from March

through October, 2009–2012......................................................................................................13

8. Graphs showing annual runoff and runoff as a percentage of annual precipitation 

for Discovery Farms in North Dakota from March through October 2009–2012 ..............14

9. Graphs showing monthly precipitation and monthly mean precipitation for Discovery 

Farms in North Dakota, 2009–2012...........................................................................................16
iv

10. Graphs showing monthly runoff and monthly mean runoff for surface drainage

sites at Discovery Farms in North Dakota, 2009–2012..........................................................17

11. Boxplots showing distribution of constituent concentrations at Underwood

Discovery Farms, North Dakota, 2008–2012 ...........................................................................19

12. Pie charts showing speciation of nitrogen at Underwood and Dazey Farms,

North Dakota, 2008–2012 ..........................................................................................................21

13. Graphs showing annual loads for Discovery Farms in North Dakota, 2009–2012 ...........22

14. Graphs showing annual yields for Discovery Farms in North Dakota, 2009–2012...........23

15. Boxplots showing distribution of constituent concentrations at Dazey Farm,

North Dakota, 2009–2012 ...........................................................................................................24

16. Boxplots showing distribution of constituent concentrations at Embden Farm,

North Dakota, 2009–2012 ...........................................................................................................26

17. Pie charts showing speciation of nitrogen at Embden Farm, North Dakota, 

2009–2012 .....................................................................................................................................28

Tables

1. Location, elevation, drainage area, mean basin slope, flume style, date of

construction, and period of record for monitoring sites for Discovery Farms,

North Dakota .................................................................................................................................5

2. Results of quality-assurance samples for chloride, nutrient and

suspended-sediment concentrations for samples collected for Discovery Farms,

2008–12 .........................................................................................................................................12

3. Estimate of runoff for subsurface drainage tile sites, E2 and E3, using surface

drainage area at Embden Farm, 2010–12................................................................................15

4. Number of samples collected each year for Discovery Farms sites, June

2008–October 2012......................................................................................................................18
v

Conversion Factors

IInternational System of Units

Multiply By To obtain

Length

inch (in.) 2.54 centimeter (cm)

inch (in.) 25.4 millimeter (mm)

foot (ft) 0.3048 meter (m)

mile (mi) 1.609 kilometer (km)

Area

acre 4,047 square meter (m2

)

acre 0.4047 hectare (ha)

acre 0.4047 square hectometer (hm2

) 

acre 0.004047 square kilometer (km2

)

Volume

cubic foot (ft3

) 28.32 cubic decimeter (dm3) 

cubic foot (ft3

) 0.02832 cubic meter (m3) 

million gallons (Mgal) 3,785 cubic meter (m3

)

Flow rate

cubic foot per second (ft3

/s) 0.02832 cubic meter per second (m3/s)

Mass

pound per day (lb/d) 0.4536 kilogram (kg) 

Temperature in degrees Fahrenheit (°F) may be converted to degrees Celsius (°C) as follows:

°C=(°F-32)/1.8

Supplemental Information 

Concentrations of chemical constituents in water are given in milligrams per liter (mg/L).

Water-Quality Characteristics in Runoff for Three 

Discovery Farms in North Dakota, 2008–12

By Rochelle A. Nustad, Kathleen M. Rowland, and Ronald G. Wiederholt

Abstract

North Dakota has implemented several policies with 

the goal of minimizing runoff from animal feeding operations; however, little data have been collected to evaluate the 

effects of runoff from feeding operations on water quality 

or improvements in water quality resulting from changes in 

animal feeding operation practices. In response to this lack of 

data, the U.S. Geological Survey in cooperation with North 

Dakota State University Agriculture Research Extension 

and in collaboration with North Dakota State Department of 

Health, North Dakota State Water Commission, U.S. Environmental Protection Agency, and several agricultural producers 

helped organize a Discovery Farms program in North Dakota 

in 2007. Discharge measurements and water-quality samples 

collected at the three Farms (Underwood, Dazey, and Embden) 

were used to describe water-quality characteristics in runoff, 

and compute estimates of annual loads and yields for selected 

constituents from spring 2008 through fall 2012.

At Underwood Farm, concentrations generally decreased 

from upstream to downstream because of proximity to the 

feedlot and grassy depressions located between sites. With 

the exception of nitrate plus nitrite, a statistically significant 

decrease in concentration from upstream to downstream 

generally was observed. For nitrate plus nitrite, the surface 

runoff processes that dominated other constituents (dilution, settling out, vegetative uptake) were moderated by 

other processes specific to nitrate plus nitrite (high solubility, 

nitrification, and denitrification), resulting in no significant 

change in concentrations from upstream to downstream. For 

constituents other than nitrate plus nitrite, dilution, settling out 

of sediment particles, and vegetative uptake likely contributed 

to the decrease in constituent concentration from upstream to 

downstream. The predominant form of nitrogen at Underwood 

Farm was organic nitrogen (59 percent of total nitrogen), 

which is consistent with surface drainage sites at Discovery 

Farms in Wisconsin. For chloride, suspended sediment, total 

phosphorus, and ammonia, the largest loads typically were at 

the upstream site, and the smallest loads were observed at the 

downstream site. Consistent with annual flow volumes, for 

constituents other than nitrate plus nitrite, the smallest annual 

loads were in 2012, and the largest annual loads were in 2011. 

Although the largest nitrate plus nitrite loads generally were 

observed in 2010, 2011 was the year with the largest amount 

of flow volume. The temporal distribution of precipitation may 

have contributed to the larger nitrate plus nitrite loads in 2010. 

With the exception of nitrate plus nitrite, the largest annual 

yields at Underwood Farm were in 2011 at the most upstream 

site, and the smallest annual yields were in 2012 at the most 

downstream site. The larger yield in 2011 relates well with 

annual runoff in 2011 at Underwood Farm, which, on average, 

was 1.5 times greater than runoff in 2010. 

Variability in concentrations among sites at Dazey Farm 

was predominantly affected by local topography and surfacegroundwater interactions. Chloride concentrations were highest at the site farthest downstream likely because of groundwater contribution. Suspended sediment, total phosphorus, 

and ammonia concentrations were significantly lower at the 

downstream site likely because of dilution and settling out of 

sediment. Nitrate plus nitrite concentrations were not significantly different from upstream to downstream likely because 

of surface-groundwater interaction, nitrification, and denitrification. Similar to Underwood Farm, the predominant form of 

nitrogen at Dazey Farm was organic nitrogen. For suspended 

sediment, total phosphorus, and ammonia, annual loads and 

yields at Dazey Farm were larger in 2010 than 2011, which 

was consistent with the pattern in precipitation and runoff. 

For chloride and nitrate plus nitrite, the largest annual loads 

did not coincide with the year of largest runoff, which may be 

caused by groundwater interaction with the surface runoff. 

At Embden Farm, constituent concentrations were significantly different between surface drainage and subsurface 

drainage systems for all constituents except ammonia. Total 

phosphorus concentrations were significantly higher at the 

surface drainage site. Nitrate plus nitrite concentrations and 

total nitrogen concentrations were 10 to 100 times higher at 

subsurface drainage sites compared to the surface drainage 

site. Similar to nitrate plus nitrite, chloride concentrations 

were significantly higher at subsurface drainage sites than 

the surface drainage site. High solubility allows nitrate plus 

nitrite to readily flow through the soil and into tile lines, but 

groundwater also may be contributing to higher nitrate plus 

nitrite and chloride concentrations at the subsurface drainage 

sites. The speciation of nitrogen between the surface drainage site and subsurface drainage sites was distinctly different. 
2 Water-Quality Characteristics in Runoff for Three Discovery Farms in North Dakota, 2008–12

The predominant form of nitrogen at the surface drainage site 

was organic nitrogen (68 percent), which is consistent with 

surface drainage sites at Underwood and Dazey Farms. For the 

subsurface drainage sites, the predominant form of nitrogen 

was nitrate plus nitrite (93 percent), which is consistent with 

subsurface drainage sites at Discovery Farms in Wisconsin. At 

the Embden Farm, during the wet years of 2010 and 2011, the 

subsurface drainage sites had the highest flow volumes and the 

largest annual loads. 

Consistent patterns in water quality emerged at each 

individual farm, but similarities among farms also were 

observed. Suspended sediment, total phosphorus, and ammonia concentrations generally decreased downstream from 

feeding areas, and were primarily affected by surface runoff 

processes such as dilution, settling out of sediment, or vegetative uptake. Because surface runoff affects these constituents, 

increased annual surface runoff tended to result in increased 

loads and yields. No significant change in nitrate plus nitrite 

concentration were observed downstream from feeding areas 

because additional processes such as high solubility, nitrification, denitrification, and surface-groundwater interaction affect 

nitrate plus nitrite. For nitrate plus nitrite, increases in annual 

runoff did not consistently relate to increases in annual loads 

and yields. It seems that temporal distribution of precipitation and surface-groundwater interaction affected nitrate plus 

nitrite loads and yields. For surface drainage sites, the primary 

form of nitrogen was organic nitrogen whereas for subsurface 

drainage sites, the primary form of nitrogen was nitrate plus 

nitrite nitrogen. 

Introduction

In North Dakota, animal feeding operations, manure 

disposal, and fertilizer application to crops commonly increase 

nutrient-bearing materials on the landscape. During runoff 

conditions, nutrients and other constituents in the materials 

could enter waterways and potentially contaminate downstream water supplies. North Dakota has a well-established 

group of watershed projects that have successfully improved 

manure management across the State (North Dakota Department of Health, 2012). North Dakota also has implemented 

several policies with the goal of minimizing runoff from animal feeding operations (North Dakota Department of Health, 

2014); however, little data have been collected to evaluate 

the effects of runoff from feeding operations on water quality 

or improvements in water quality resulting from changes in 

animal feeding operation practices. In response to this lack of 

data, the U.S. Geological Survey (USGS) in cooperation with 

North Dakota State University Agriculture Research Extension 

and in collaboration with North Dakota State Department of 

Health, North Dakota State Water Commission, U.S. Environmental Protection Agency, and several agricultural producers 

helped organize a Discovery Farms program in North Dakota 

in 2007. This program, modeled after the Wisconsin Discovery 

Farms program (Stuntebeck and others, 2008), was established to collect and analyze water-quality information from 

agricultural lands and livestock feeding areas. An additional 

goal of Discovery Farms is to document the effectiveness of 

producer-driven solutions at minimizing negative effects on 

water quality.

Constituents that are present in runoff from crop and 

cattle operations include nutrients such as phosphorus and 

nitrogen, chloride, and suspended sediment. Runoff, measured 

in depth, is defined as the amount of water coming off the 

landscape in response to precipitation. The amount of each 

constituent in runoff can be expressed by concentration (mass 

per unit volume), loads (mass per unit time), or yields (mass 

per unit area). Constituents are affected by a variety of factors 

including background level from natural sources, land use 

management, topography, and soil type. Excess amounts of 

these constituents affect receiving waters such as rivers and 

lakes. Farm practices that prevent loss of these constituents are 

beneficial to receiving waters and to farmers that implement 

those practices. 

Discovery Farms in North Dakota are working farms and 

ranches in the State whose operators are collaborating with 

local, State, and Federal natural resources agencies to demonstrate and evaluate the effectiveness of different management 

practices in reducing negative environmental effects while 

maintaining profitability. Goals of Discovery Farms include 

the following: (1) encourage responsible development of a 

diverse livestock industry in the State that will benefit crop 

and livestock producers while protecting the natural resources; 

(2) ensure a coordinated approach to the development and 

management of regulatory practices; (3) document and quantify the positive and negative effects of farming and ranching 

practices; (4) provide unbiased, reliable information to the 

general public, agricultural producers, and policymakers; (5) 

enhance communication and information sharing among agricultural producers, researchers, educators, the general public, 

and regulatory agencies; and (6) provide a platform for agricultural systems research through cooperation with interested 

research institutions (North Dakota State University, 2009).

Purpose and Scope

This report describes the three Discovery Farms in North 

Dakota, and procedures used to obtain discharge and waterquality samples. The purpose of this report is to describe 

water-quality characteristics in runoff, and estimate annual 

loads and yields for selected constituents from spring 2008 

through fall 2012 at the three Discovery Farms in North 

Dakota. In addition, precipitation, flow volume, and runoff are 

presented.
Descriptions of the Discovery Farms in North Dakota 3

Descriptions of the Discovery Farms in 

North Dakota

Discovery Farms were established in North Dakota in 

late 2007 near Underwood in McLean County (hereafter 

referred to as “Underwood Farm”), in early 2008 near Dazey 

in Barnes County (hereafter referred to as “Dazey Farm”), and 

in late 2008 near Embden in Cass County (hereafter referred 

to as “Embden Farm”) (fig. 1). Three data-collection sites 

were located at each farm. Each site contained a refrigerated 

automated water sampler that holds 24 1,000-milliliter (mL) 

sample bottles, a datalogger, a bubble-gage system (Sauer and 

Turnipseed, 2010), and a flume (table 1, fig. 2). At Embden 

Farm, an extra-large 60-degree V trapezoidal flume was 

installed in the ground at sites E2 and E3 to capture runoff 

from subsurface drainage tiles. A tipping-bucket rain gage was 

installed at one site on each farm (table 1). Additional location 

information for the farms is presented in table 1. 

The climate of Discovery Farms in North Dakota is 

classified as continental with a similar range in average 

temperatures and precipitation among the farms. The average air temperature, based on the period from 1981 to 2010, 

ranges from 40 degrees Fahrenheit (oF) near Dazey Farm to 

43 oF near Embden Farm (North Dakota Agricultural Weather 

Network, 2013). Summer (June–August) temperatures average between 63 and 69 oF, and winter (December–February) 

temperatures average between 8 and 17 oF (North Dakota 

Agricultural Weather Network, 2013). Average annual precipitation for the same period ranges from 17.6 inches (in.) 

near Underwood Farm to 22.3 in. near Embden Farm (North 

Dakota Agricultural Weather Network, 2013). Most of the precipitation falls as rain in May through August near Dazey and 

Embden Farms, and May through July near Underwood Farm 

(North Dakota Agricultural Weather Network, 2013). Precipitation amounts are least during winter months averaging 

between 0.44 and 0.62 in. (North Dakota Agricultural Weather 

Network, 2013). During winter months, precipitation typically 

falls as snow. Average annual snowfall ranges from about 35 

in. near Dazey Farm to 40 in. near Underwood Farm (North 

Dakota State Climate Office, 2013a). The average number of 

days of snow cover of 1 in. or more is about 100 days for all 

of the farms (Jensen, [n.d.]). 

Underwood Farm

Underwood Farm is a crop and cattle operation located 

about 8 miles (mi) west of Underwood, North Dakota, and 

about 3 mi east of the Missouri River (fig. 1). Underwood 

Farm is located on level to rolling topography underlain by 

the moderately well-drained silty loam soils of the Coteau 

Slope physiographic region of North Dakota (Bluemle and 

Biek, 2007). A feedlot is located at the southeast quadrant of 

the farmstead, and cropland makes up most of the surrounding area (fig. 3). Beef cows are placed in the feedlot during the 

winter months and remain there through the early spring during calving. Once the cows have calved, they are moved to an 

offsite pasture (not shown) with their calves during the summer months and are kept together until weaning in early fall. 

Weaned calves also are placed in the feedlot in the fall and 

remain there until late winter before being moved to finishing 

lots in other parts of the state. Most of the pens in the feedlot 

are empty during the summer months. Manure accumulation 

from the winter months is scraped and piled in the pens after 

the cows and calves are sent to pasture. Manure is stored in the 

empty pens until late summer when it is spread on surrounding 

cropland to be used as a crop fertilizer. Runoff from the farmstead and feedlot enters a waterway that generally trends from 

north to south (fig. 3). Runoff from the farm contributes to a 

small drainage basin that flows into the Missouri River. Three 

data-collection sites are located along the waterway south of 

the farm (fig. 3). Shelters were brought in or built onsite to 

house the automated samplers and the dataloggers. The drainage area for each of the sites ranges from 87 to 1,976 acres 

(table 1).

Dazey Farm

Dazey Farm is a crop and cattle operation located about 

6 mi east and 2 mi south of Dazey, N. Dak., and 3 mi west 

of Lake Ashtabula (fig. 1). Dazey Farm is located on sloping 

topography underlain by well-drained loams of the Glaciated 

Plains physiographic region of North Dakota (Bluemle and 

Biek, 2007). A feedlot and winter cattle feeding area is located 

to the west of the farmhouse, and cropland makes up most 

of the surrounding area (fig. 4). After being brought in from 

pasture in the fall, the beef cows are wintered on the cattle 

feeding area, which is primarily cropland. The cattle graze the 

crop residue and, if supplemented with stored feed, the feeding 

areas are randomly located in the cropland area to decrease 

the amount of concentrated feeding areas. Feeding area runoff 

from the cropland, which can flow rapidly, travels mostly 

eastward along a waterway into Baldhill Creek (fig. 4) and 

then into Lake Ashtabula (not shown). The waterway traverses 

through a pasture, which serves as a calving area for the beef 

cows in early spring. Three data-collection sites were established, and shelters were built at the sites along the waterway 

to house the automated samplers and the dataloggers. The 

most downstream site (D3) receives runoff from the cattle 

feeding area as well as runoff from cropland on neighboring 

farms. The drainage area for the three sites ranges from 30 to 

341 acres (table 1). 

Embden Farm

Embden Farm is a combination crop and cattle production operation located about 8 mi south of Embden, N. Dak. 

and about 1 mi north of the Maple River (fig. 1). Embden 

Farm is located on nearly level ground underlain by sandy 

loam soils of the Red River Valley physiographic region of 
4 Water-Quality Characteristics in Runoff for Three Discovery Farms in North Dakota, 2008–12

0 50 75

75

100 MILES 25

0 50 100 KILOMETERS 25

 LakeAshtabula

CASS COUNTY

BARNESCOUNTY

MANITOBA SASKATCHEWAN

MINNESOTA

MONTANA

NORTH DAKOTA

SOUTH DAKOTA

MCLEAN COUNTY

Base from U.S. Geological Survey digital data, 1983Universal Transverse Mercator projectionZone 14

98°

49°48°47°46°

100° 102° 104°

Missouri River

River

Maple

River

Underwood

Turtle Lake

Bismarck

Leonard

Underwood

Farm

Dazey

Farm

Sheyenne

Embden

BaldhillCreek

Embden Farm

Dazey

Figure 1. Location of Discovery Farms in North Dakota.
Descriptions of the Discovery Farms in North Dakota 

5

Table 1. Location, elevation, drainage area, mean basin slope, flume style, date of construction, and period of record for monitoring sites for Discovery Farms, North Dakota.[USGS, U.S. Geological Survey; --, not determined; ft, feet; H, style of flume; V, style of flume]

Discovery 

farm name Site number USGS station name Abbreviated name County Elevation, in feet Drainage area, 

acresa

Mean basin 

slope, 

in percenta

Flume size/ 

flume style Constructed Period of record

Underwood 472731101175500 Discovery Farms Waterway Site 1 

near Underwood, North Dakota

U1 McLean 1,950 87 -- 2.0 ft/H Fall 2007 June 2008–

October 2012

Underwood 472727101175000 Discovery Farms Waterway Site 2 

near Underwood, North Dakota

U2b McLean 1,930 1,918 -- 2.0 ft/H Fall 2007 June 2008–

October 2012

Underwood 472709101175100 Discovery Farms Waterway Site 3 

near Underwood, North Dakota

U3 McLean 1,915 1,976 1.1 2.0 ft/H Fall 2007 June 2008–

October 2012

Dazey 470856098050600 Discovery Farms Waterway Site 1 

near Dazey, North Dakota

D1b Barnes 1,370 30 -- 2.0 ft/H Spring 2008 October 2008– 

June 2011

Dazey 470856098045800 Discovery Farms Waterway Site 2 

near Dazey, North Dakota

D2 Barnes 1,330 61 -- 2.0 ft/H Spring 2008 March 2009–

April 2011

Dazey 470850098044500 Discovery Farms Waterway Site 3 

near Dazey, North Dakota

D3 Barnes 1,280 341 3.6 2.5 ft/H Spring 2008 April 2009–

October 2012

Embden 464115097255000 Discovery Farms Waterway Site 1 

near Embden, North Dakota

E1b Cass 1,050 175 0.3 2.0 ft/H Fall 2008 April 2009–

October 2012

Embden 464115097254700 Discovery Farms Waterway Site 2 

near Embden, North Dakota

E2 Cass 1,050 80c -- Extra-large/ 

60-degree V

trapezoidial 

Fall 2008 June 2009–

 October 2012

Embden 464114097260900 Discovery Farms Waterway Site 3 

near Embden, North Dakota

E3 Cass 1,055 80c -- Extra-large/ 

60-degree V

trapezoidial

Fall 2008 April 2009–

October 2012

aThe North Dakota StreamStats application was used to determine drainage area for each site and mean basin slope for the most downstream site (U.S. Geological Survey, 2014).bPrecipitation gage installed at these sites.cDrainage area is an estimate based on surface topography, but due to fluctuating water table elevations, exact land acreage drained could not be determined.
6 Water-Quality Characteristics in Runoff for Three Discovery Farms in North Dakota, 2008–12

Datalogger

Refrigerated/

automated

water sampler

Bubble-gage system

A

C D

B

Figure 2. Equipment installed at Discovery Farms sites in North Dakota. A, Inside the gage house is a refrigerated automated water 

sampler, datalogger, bubble-gage system; B, 24 1,000-milliliter sample bottles inside the water sampler; C, a 2.0 foot H type flume; and D, 

an extra-large 60-degree V type trapezoidal flume.

North Dakota (Bluemle and Biek, 2007). Although Embden Farm has a cattle operation, the data collection sites are 

located in an area only affected by runoff from cropland. 

Crops grown on the farm include corn, soybeans, wheat, and 

alfalfa. The soils vary from well-drained to somewhat poorly 

drained, and runoff is generally slow. Subsurface drainage tiles 

were installed in an agricultural field at the farm in 2009, and 

water from the drains can flow into the Maple River (fig. 5). 

The field being monitored has two separate subsurface drainage tile systems that drain the east and west halves of the field, 

respectively (fig. 5). Historically, the east and west fields have 

been treated as one unit; therefore, the two subsurface drainage tile systems provide a paired drainage system for comparative analyses. On the east field, most of the field surface 

drainage exits in the southeast corner of the field adjacent to 

the outlet for the east subsurface drainage system. Therefore, 

only two data shelters are required for the three data-collection 

sites at this farm. One shelter houses a data logger and two 

automated samplers (one for the surface drainage site [E1] and 

the other for a flume inserted into the drain tile outlet [E2]). 

The second shelter is located west of the first shelter and contains an automated water-quality sampler, a flume inserted into 

drain tile under the ground (E3), and a datalogger. The data 

shelters are located next to the edge of cropped fields along a 

township road. Drainage areas based on surface topography 

are provided in table 1, but because of fluctuating water table 

elevations the exact land acreage drained by the subsurface 

drainage sites could not be determined for sites E2 and E3. 

Methods

Collection of discharge data, precipitation data, and 

water-quality samples began in June 2008 at Underwood 

Farm, October 2008 at Dazey Farm, and April 2009 at 

Embden Farm. Water-quality samples were collected during 
Methods 7

0 750 1,500 FEET

0 250 500 METERS

Base from U.S. Department of Agriculture

National Agricultural Imagery Program, 2012

Global Coordinate System 1983

National Geodetic Vertical Datum 29 NORTH DAKOTA

101°18’ 101°17’30”

47°27’30”

47°27’

U1

U2

U3

EXPLANATION

Site and identifier U1

Feedlot

Waterway

Underwood

Farm

Figure 3. Location of monitoring sites and aerial view of Underwood Farm in North Dakota.
8 Water-Quality Characteristics in Runoff for Three Discovery Farms in North Dakota, 2008–12

#

98°05’30” 98°05’

47°09’

47°09’30”

0 750 1,500 FEET

0 250 500 METERS

D1

D3

Base from U.S. Department of Agriculture

National Agricultural Imagery Program, 2012

Global Coordinate System 1983

National Geodetic Vertical Datum 29 NORTH DAKOTA

Baldhill

Creek

# D2

#

#

EXPLANATION

Site and identifier D1

Feedlot Waterway

Winter feeding area

Spring calving area

Dazey

Farm

Figure 4. Location of monitoring sites and aerial view of Dazey Farm in North Dakota.
Methods 9

97°26’

46°41’30”

46°41’

NORTH DAKOTA

0 750 1,500 FEET

0 250 500 METERS

Maple River

97°26’30”

E3

E1 E2

Base from U.S. Department of Agriculture

National Agricultural Imagery Program, 2012

Global Coordinate System 1983

National Geodetic Vertical Datum 29 

EXPLANATION

Site and identifier E1

Drain tiles

West field

East field

Embden Farm

Figure 5. Location of monitoring sites and aerial view of Embden Farm in North Dakota.
10 Water-Quality Characteristics in Runoff for Three Discovery Farms in North Dakota, 2008–12

spring snowmelt and precipitation runoff events. Data analyses 

include annual and monthly summaries of precipitation and 

runoff data, summaries of water-quality concentrations, and 

computation of annual loads and yields. 

Data Collection

Discharge data primarily were measured using flumes, 

but under some circumstances discharges had to be estimated. 

At each site, gage height was measured within the flume 

using the bubble-gage system (Sauer and Turnipseed, 2010).

Discharge was calculated from gage height using an equation 

that was developed specifically for each flume type (Tracom, 

2014a, 2014b, 2014c). Discharge was estimated during spring 

snowmelt because of ice and snow-affected gage heights. 

During the spring freeze-thaw cycle, ice dams and snow drifts 

in the flume caused pools of water around the flume resulting 

in erroneous gage-height values that translated into erroneous discharge values. Flumes were checked during site visits 

to determine if the recorded discharge values were reliable. 

When discharge values were deemed unreliable, discharge was 

estimated based on notes from site visits, temperature, and 

comparisons with other sites at the farm. Subsequent to the 

first year of data collection, discharge was collected in 15-minute increments and stored on the datalogger at each site. 

Cellular telemetry was used to relay data to servers located at 

the USGS North Dakota Water Science Center in Bismarck, N. 

Dak. (fig. 1) for analysis and archiving. All data from the dataloggers were stored in the National Water Information System 

(NWIS; U.S. Geological Survey, 2013).

Precipitation data collected at U2, D1, and E1 were 

compared with the nearest North Dakota Agricultural Network 

(NDAWN) sites Dazey, Leonard, and Turtle Lake, respectively 

(fig. 1; North Dakota Agricultural Weather Network, 2013). 

At D1, missing data resulted in consistently low precipitation 

values compared with the Dazey NDAWN site, so annual and 

monthly precipitation data from the Dazey NDAWN site were 

used in this report to represent the Dazey Farm precipitation 

data. Precipitation collected from the farms sites and NDAWN 

sites were available from April through October because the 

gaging equipment located at these sites measures precipitation 

that falls as rain, and not snow. Estimates of precipitation for 

March 2008 and 2009 were obtained from the North Dakota 

State Climate Office (North Dakota State Climate Office, 

2013b). Estimates of March precipitation for 2010 through 

2012 were obtained from Community Collaborative Rain Hail 

and Snow Network (CoCoRaHS) sites located nearest each 

farm (Community Collaborative Rain Hail and Snow Network, 2013). 

Depending on the site and the time of year, water-quality 

samples were collected using an automated water sampler or 

as a grab sample. The automated water samplers were programmed to collect a sample from the flume when certain criteria were met. Grab samples required a person to physically 

be on site to either fill up the sample bottle by hand or use the 

automated sampler to pump water into the sample bottle. For 

samples collected by the automated water sampler, the number 

of sampling bottles collected during a runoff event varied 

with the volume and duration of the event. A maximum of 24 

bottles could be collected by an automated sampler during one 

runoff event. Water samples from the automated sampler were 

removed as soon as possible, and the full bottles were replaced 

with clean, empty bottles. 

At Underwood Farm and Dazey Farm, most samples 

were collected by the automated water sampler during runoff 

events. Grab samples were collected for quality control, when 

the automated sampler was malfunctioning, or during the 

spring freeze-thaw cycle when ice dams in the flume created 

problems with sample collection. Automated water samplers 

were programmed to start sampling after a specific volume of 

water had passed through the flume. This specified volume of 

water was estimated based on possible rainfall amounts from 

showers and thunderstorms that were expected during the 

year. Although the automated sampler was programmed for 

a specified volume of water initially, the sampling frequency 

of the automated samplers could be adjusted during a runoff 

event. Repeated sampling was done when flow continued for 

a prolonged period of time. The frequency and duration of 

water sampling varied from site to site based on antecedent 

conditions, shelter location, and runoff event. Sample times, 

discharge at time of sample, number of bottles filled, and other 

information pertaining to the sampling event was stored on the 

datalogger. 

At Embden Farm, nearly all samples were collected as 

grab samples. At the surface drainage site, E1, grab samples 

were collected by hand because the majority of runoff happens in the spring and the flume is readily accessible. For the 

two subsurface drainage sites, E2 and E3, grab samples were 

collected because runoff lasts several days to weeks. At site 

E2, grab samples were collected by hand. At site E3, the automated sampler was used to pump water into the sample bottle 

because the flume was difficult to access.

Water-quality samples were analyzed by the North 

Dakota State Department of Health Division of Laboratory 

Services according to methods and procedures described in 

Clesceri and others (1999) or the U.S. Environmental Protection Agency (2013a). Samples were analyzed for chloride, 

total ammonia plus organic nitrogen, total ammonia, nitrate 

plus nitrite plus nitrogen, total nitrogen, and total phosphorus. For all samples, concentration analyses for chloride were 

made from filtered samples, and analyses for other constituents were made from unfiltered samples. Starting in spring of 

2010, filtered samples also were analyzed to determine nutrient concentrations. Nutrient concentrations of filtered samples 

are not presented in this report, but are available in the USGS 

NWIS database (U.S. Geological Survey, 2013). Because of 

known biases, not all analyzed forms of nitrogen are presented 

in this report. Total ammonia plus organic nitrogen concentrations are not presented. Total nitrogen concentrations are summarized but not used to compute loads or yields, and organic 

nitrogen is expressed as a percent. Total nitrogen was analyzed 
Quality Assurance and Quality Control 11

using alkaline-persulfate digestion, which has been determined 

to be negatively biased in the presence of sediment concentrations (Rus and others, 2013). Because laboratory results of 

total ammonia plus organic nitrogen was a calculated value 

based on the difference of total nitrogen and nitrate plus nitrite 

nitrogen, results also are biased. Although total nitrogen was 

known to be biased, to estimate the speciation of nitrogen at 

a farm, total nitrogen was used in expressing organic nitrogen, ammonia nitrogen, and nitrate plus nitrite nitrogen as a 

percentage of total nitrogen. For surface drainage sites, U1-3, 

D1-3, and E1, samples also were analyzed for suspendedsediment concentration by the USGS Iowa Water Science 

Sediment Laboratory in Iowa City, Iowa, following procedures 

described in Guy (1969). All water-quality data collected in 

this study were stored in the USGS NWIS database (U.S. 

Geological Survey, 2013).

Data Presentation and Analysis

Annual and monthly mean precipitation and runoff 

data were presented from March through October for 2008 

through 2012. Annual precipitation for each farm was compared with the 30-year mean annual precipitation. For a given 

year, data for each site were presented from March 1 through 

October 31. Runoff was computed for sites U1-3, D3, and 

E1 but runoff could be not computed for D1 and D2 because 

not enough discharge data were collected. For subsurface tile 

drainage sites, E2 and E3, runoff was estimated from surface 

drainage area, but because of uncertainty in the drainage area, 

runoff was not compared with other sites. For water-quality 

constituents, statistical summaries of the maximum; minimum; and 10th, 25th, 50th, 75th, and 90th percentiles were 

computed and presented graphically using boxplots. The 

boxplots were then used to compare concentrations of selected 

water-quality constituents. Boxplots of suspended sediment 

concentrations were not presented for Embden Farm because 

suspended sediment samples were not collected at the subsurface tile drainage sites (E2 and E3), and only a few samples 

were collected at the surface drainage site at Embden Farm 

(E1). In the case of censored data (data that contains values 

less than the laboratory reporting levels), the nonparametric 

Kaplan-Meier statistical method was used to estimate the 

statistical summary (Helsel, 2005). Concentrations were tested 

for differences among sites using the Wilcoxon rank sum test 

(Helsel and Hirsch, 2002). The Wilcoxon rank sum test is a 

nonparametric test that determines the probability (p) that 

the distribution of the dataset is similar to the distribution set 

within a selected level of significance. Because many comparisons were made, for this report, a level of significance of 0.01 

(α=0.01) was selected. Although likely underestimated, total 

nitrogen concentrations were used to estimate the speciation of 

nitrogen in the runoff at the Discovery Farms. Ammonia and 

nitrate plus nitrite nitrogen as a percentage of total nitrogen 

was computed. The percentages of ammonia and nitrate plus 

nitrite were then summed and subtracted from 100, and the 

remaining percentage was estimated to be organic nitrogen. 

Daily loads were computed for sites using estimated daily 

mean values of constituent concentration and discharge data 

for the periods of record from select Discovery Farm sites. For 

each day of existing records, values of constituent concentration and 15-minute discharge were averaged arithmetically 

to produce estimated daily-mean constituent concentrations 

and discharges. For days without existing records, daily-mean 

constituent concentrations were estimated using linear interpolation, and daily-mean discharge values were estimated using 

data from the other sites at the farms or from other ancillary 

information. Daily loads (L) were estimated using the dailymean concentrations (C) and discharges (Q) according to the 

equation:

L= 5.39 x C x Q, (1)

where

L is the daily constituent load, in pounds per 

day;

5.39 is the conversion factor used to convert units 

of milligrams per liter and cubic feet per 

second to units of pounds per day;

C is the daily mean constituent concentration, in 

milligrams per liter; and

Q is the daily mean discharge, in cubic feet per 

second. 

Quality Assurance and Quality Control

Water-quality samples were collected by USGS personnel with assistance from cooperating agencies. Equipment 

used for sampling was calibrated according to manufacturer’s 

specifications and periodically checked in the field. Upon 

each visit to the data shelters, equipment was inspected for 

malfunctions to ensure valid samples were being collected. 

Also, field instruments were cleaned periodically according to 

instructions and protocols from the USGS, North Dakota State 

Department of Health, and instrument manufacturers (U.S. 

Geological Survey, variously dated; Stuntebeck and others, 

2008). 

Blank and replicate samples were collected to estimate 

the variability in the laboratory analysis and reproducibility in 

the collection of samples. A total of three blank samples were 

collected and analyzed for chloride and nutrients. All constituents for blank samples were near or less than the laboratory 

reporting level. Thirty-one replicate samples were collected 

and analyzed for chloride, total phosphorus, total ammonia, 

and nitrate plus nitrite. For suspended sediment, nine replicate 

samples were collected and analyzed. The analytical variability of replicate samples for constituents other than suspended 

sediment was small with average differences ranging from 

3.5 percent for chloride to 12.9 percent for total phosphorus. 
12 Water-Quality Characteristics in Runoff for Three Discovery Farms in North Dakota, 2008–12

The average difference for suspended sediment was 19.8 percent (table 2). Higher variability in replicate suspended sediment samples likely is related to natural variability in runoff 

concentrations. Results from quality assurance and quality 

control data indicate that cleaning procedures were adequate to 

prevent cross-contamination of samples, and laboratory results 

were reproducible. 

Table 2. Results of quality-assurance samples for chloride, 

nutrient and suspended-sediment concentrations for samples 

collected for Discovery Farms, 2008–12.

[Calculation of percent difference is:|(x1-x2)/(x1+x2)/2|(100), where x1=sample, 

x2=sequential replicate; N, nitrogen]

Constituent Number of samples Average percent 

difference

Chloride 31 3.5

Suspended sediment 9 19.8

Total phosphorus 31 12.9

Total ammonia as N 31 6.0

Nitrate plus nitrite 31 12.7

2009 2010 2011 2012 2010 2011 2010 2011 2012

Precipitation, in inches

0

5

10

15

20

25

30

30-year mean (1981–2010)

Underwood

Farm

Dazey

Farm

Embden

Farm

EXPLANATION

Year

Figure 6. Annual precipitation for Discovery Farms in North Dakota from March through October 

(2009–2012) and 30-year mean annual precipitation (1981–2010); the 30-year mean annual is an average 

of National Weather Service sites located near the Underwood, Dazey, and Embden Farms from March 

through October (North Dakota Agricultural Network, 2012).

Precipitation, Flow Volume, and Runoff

Precipitation, flow volume, and runoff data collected at 

all three farms were used to understand factors affecting runoff 

from agricultural fields. Annual statistics presented below are 

based on data from March through October. Annual statistics 

were computed only if data were available for the entire period 

from March through October. Flow volume is presented to 

compare surface drainage sites with the two drainage tile sites 

at the Embden Farm. Runoff is presented in inches only for 

surface drainage sites. An estimate of runoff for the subsurface 

drainage tile sites at Embden Farm computed from surface 

area drainage indicates that groundwater is a component of the 

runoff at E2 and E3. 

Annual Precipitation, Flow Volume, and Runoff

Annual precipitation (March through October) was 

lowest in 2012 and highest in 2010 ranging from 11.08 in. at 

Underwood Farm in 2012 to 26.6 in. at Embden Farm in 2010 

(fig. 6). For all farms, the annual precipitation in 2010 was 

greater than the 30-year mean annual precipitation (March 

through October of 1981–2010) of 17.94 in. In 2011, the 
Precipitation, Flow Volume, and Runoff 13

annual precipitation for all the farms was within 20 percent 

of the 30-year mean, but in 2012 the annual precipitation for 

Underwood and Embden Farms was well below the 30-year 

mean. 

Similar to precipitation, the annual flow volume (March 

through October) was lowest in 2012 (fig. 7). For all years 

at farm sites, annual flow volumes ranged from 0.17 million 

gallons (Mgal; E2, 2012) to 56 Mgal (E3, 2010). Annual flow 

volume was largest in 2010 for Dazey and Embden Farms, but 

largest in 2011 for Underwood Farm. At Underwood Farm, the 

largest volume for all the years (34.3 Mgal) was at the most 

downstream site, U3, in 2011 (fig. 7). The large flow volumes 

in 2010 and 2011 at E2 and E3 likely are related to consecutive years of near average precipitation. Wet fall periods in 

2009 and 2010 caused the subsurface drainage sites (E2 and 

E3) to have flow through the winter. Flow for the subsurface 

drainage sites (E2 and E3) from November through February is not included in figure 7, but ranged from about 3 to 

6.9 Mgal. 

Annual runoff for all surface drainage sites averaged 

1.3 inches or 7.6 percent of the annual precipitation (fig. 8), 

which is slightly lower than the annual runoff of 2.6 in. or 

8.0 percent of the annual precipitation reported for Discovery 

Farms in Wisconsin (Stuntebeck and others, 2011). Annual 

runoff for all surface drainage sites (U1-3, D3, and E1) ranged 

from less than 0.1 in. in 2012 at U2, U3, and E1 to 6.0 in. at 

U1 in 2011, and percentage of runoff varied from less than 

0.1 percent at U2, U3, and E1 in 2012 to 35 percent at U1 in 

2011 (fig. 8). Although 2010 had the highest annual precipitation for all farms, the highest annual runoff for Underwood 

and Embden Farms was in 2011 (figs. 6 and 8). Precipitation, 

rainfall intensity, and soil condition (antecedent moisture, 

frozen, or thawed) likely were important factors that affected 

annual runoff (Stuntebeck and others, 2011). Because of subsurface drainage tiles and lower slope (table 1), soil conditions 

more likely affect runoff at the Embden Farm surface drainage 

site (E1) than the other surface drainage sites. At E1, precipitation has to be continuous and persistent for runoff to be 

measureable. In contrast, rainfall intensity likely affects runoff 

more than soil condition at surface drainage sites at Dazey 

(D1-3) and Underwood (U1-3) Farms because of steeper slope 

(table 1) than E1 and lack of subsurface drainage tiles. 

Runoff based on surface drainage area was estimated to 

illustrate the effect of groundwater on flow measured at the 

subsurface drainage tiles (E2 and E3, table 3). Based on calculated estimates, runoff at E2 and E3 is greater than three times 

the highest year of runoff for the surface drainage sites (fig. 8). 

Furthermore, in 2011, calculated runoff exceeds precipitation. 

Physically, runoff cannot exceed precipitation. For E2 and 

E3, the surface drainage area does not account for all of the 

contributing area. Groundwater clearly is a component of the 

flows measured at E2 and E3, but the amount of flow attributed to groundwater was not investigated for this study. 

2009 2010 2011 2012 2010 2011 2010 2011 2012

Flow volume, in million gallons

0

10

20

30

40

50

60

D3

Underwood Farm Dazey Farm

Embden Farm

E1

E2

E3

U1

U2

U3

EXPLANATION EXPLANATION EXPLANATION

Underwood

Farm

Dazey

Farm

Embden

Farm

Year

Figure 7. Flow volume for Discovery Farms in North Dakota from March through October, 2009–2012.
14 Water-Quality Characteristics in Runoff for Three Discovery Farms in North Dakota, 2008–12

Underwood

Farm

Dazey

Farm

Embden

Farm

Year

2009 2010 2011 2012 2010 2011 2010 2011 2012

Runoff, in inches

0

1

2

3

4

5

6

7

Runoff, as percentage of annual precipitation 

0

10

20

30

40

D3 E1

U1

U2

U3

Mean

EXPLANATION EXPLANATION EXPLANATION Underwood Farm

Dazey Farm Embden Farm

U1 D3 E1

U2

U3

Mean

EXPLANATION EXPLANATION EXPLANATION

Underwood Farm Dazey Farm Embden Farm

Figure 8. Annual runoff and runoff as a percentage of annual precipitation for Discovery Farms in 

North Dakota from March through October 2009–2012.
Water-Quality Characteristics 15

Table 3. Estimate of runoff for subsurface drainage tile sites, E2 and E3, using surface drainage area at Embden Farm, 2010–12.

Year Precipitation 

(inches)

E2 E3

Runoff

(inches)

Runoff as a percentage of 

precipitation

Runoff 

(inches)

Runoff as a percentage of 

precipitation

2010 26.6 21.0 79.2 24.0 89.0

2011 16.9 19.2a 114 18.8a 111

2012 11.9 0.10 0.60 0.81 6.80

a

Physically, runoff cannot exceed precipitation. For these sites, the surface drainage area does not account for all of the contributing area. Groundwater is 

clearly a component of the runoff.

Monthly Precipitation and Runoff

Monthly precipitation was highly variable ranging from 

0.14 in. at Embden Farm in September 2011 to 6.6 in. at 

Dazey Farm in May of 2010 (fig. 9). For most years, monthly 

precipitation for all the farms was highest in May, June, or 

July with the highest monthly mean precipitation of about 

3.5 in. in June for all farms (fig. 9). With the exception of 

2010, precipitation generally was lowest in September or 

October. For the Dazey and Embden Farms, the monthly mean 

precipitation was lowest in October at less than 2 in. For the 

Underwood Farm, monthly mean precipitation was lowest in 

September at about 1.3 in. 

The highest amount of runoff was observed in March, 

which relates to snowmelt, and is different from patterns in 

precipitation (fig. 10). In North Dakota, little, if any, snow 

melts between November and March, and therefore most 

of the winter precipitation is included in March runoff. At 

Underwood and Embden Farms, monthly runoff was highest 

in March 2011, and at Dazey Farm, monthly runoff was highest in March of 2010 (fig. 10). At all three farms, substantial 

runoff was observed in April of 2011 because of above average precipitation in the winter of 2010–2011 and a later spring 

thaw (North Dakota State Climate Office, 2013a). Monthly 

mean runoff was highest in March ranging from about 0.3 in. 

at Embden Farm to about 1 in. at Dazey Farm. In contrast, 

monthly mean runoff was generally lowest in August through 

October at most farms (fig. 10). 

Water-Quality Characteristics

Concentrations of chloride, suspended sediment, total 

phosphorus, and several forms of nitrogen (total ammonia, 

nitrate plus nitrite nitrogen, and total nitrogen) collected 

between June 2008 through October 2012 for all sites and all 

farms are presented below. The number of samples collected 

from 2008 through 2012 varied from 17 at D2 to 152 at U1 

(table 4). The number of samples collected each year was 

affected by precipitation and equipment malfunctions. Suspended sediment concentrations are not presented for Embden 

Farm because suspended sediment samples were not collected at 

the subsurface tile drainage sites (E2 and E3), and few samples 

were collected at the surface drainage site at Embden (E1). 

Loads for chloride, suspended sediment, total phosphorus, ammonia, and nitrate plus nitrite were computed for sites 

and years in which a complete year (March through October) 

of data was available. For the Underwood Farm, loads were 

presented for all three sites, U1, U2, and U3, for 2009 through 

2012. For Dazey Farm, loads were presented for D3 for 2010 

and 2011. For the Embden Farm, loads were presented for E1, 

E2, and E3 for 2010, 2011, and 2012. For surface drainage 

sites, U1, U2, U3, D3, and E1, yields for chloride, suspended 

sediment, total phosphorus, ammonia, and nitrate plus nitrite 

were computed for the same time periods as for loads. 

Water Quality by Farm

Water-quality characteristics for sites within the same 

farm are compared in the section below. Within the same farm, 

differences in water quality among sites are evident, and consistent patterns generally emerged from the data. Among the 

farms, similarities also were observed.

Underwood Farm

At Underwood Farm (fig. 1), concentrations generally 

decreased from upstream to downstream because of proximity to the feedlot and grassy depressions located between sites 

(fig. 11). For all constituents, the maximum concentration was 

observed at the upstream site (U1), which is the site closest to the feedlot (fig. 11). With the exception of nitrate plus 

nitrite, a statistically significant decrease in concentration from 

upstream to downstream generally was observed (fig. 11). 

Median suspended sediment concentrations decreased an order 

of magnitude ranging from 444 milligrams per liter (mg/L) at 

U1 to 49 mg/L at U3, and median total phosphorus concentrations decreased from 11.4 mg/L at U1 to 3.67 mg/L at U3. 

Proximity to the feedlot resulted in higher suspended sediment 

and total phosphorus concentrations at U1. At U2 and U3, less 

concentrated runoff from surrounding crop land likely caused 

some dilution. Total phosphorus is a measure of both the 

phosphorus that is attached to suspended sediment particles 

(particulate phosphorus) and biologically available phosphorus 

(dissolved phosphorus; Minnesota Pollution Control Agency, 

2007). In the grassy depressions between sites, particulate 

phosphorus likely was removed from sediment settling out, 

and dissolved phosphorus likely was removed by vegetation. 
16 Water-Quality Characteristics in Runoff for Three Discovery Farms in North Dakota, 2008–12

0

1

2

3

4

5

6

7

2009

2010

2011

2012

Mean

Precipitation, in inches

0

1

2

3

4

5

6

7

2010

2011

Mean

0

1

2

3

4

5

6

7

2010 

2011 

2012 

Mean

Underwood Farm

Dazey Farm

Embden Farm

March April May June July August September October

EXPLANATION

EXPLANATION

EXPLANATION

Month

Figure 9. Monthly precipitation and monthly mean precipitation for Discovery Farms in North Dakota, 

2009–2012.
Water-Quality Characteristics 17

0

0.2

0.4

0.6

0.8

1.0

1.2

Runoff, in inches 

0

0.5

1.0

1.5

2.0

0

0.1

0.2

0.3

0.4

0.5

0.6

2009

2010

2011

2012

Mean

2010

2011

Mean 

2010 

2011 

2012 

Mean 

Underwood Farm

Dazey Farm

Embden Farm

EXPLANATION

EXPLANATION

EXPLANATION

March April May June July August September October

Month

Figure 10. Monthly runoff and monthly mean runoff for surface drainage sites at Discovery Farms in North 

Dakota, 2009–2012.
18 Water-Quality Characteristics in Runoff for Three Discovery Farms in North Dakota, 2008–12

Table 4. Number of samples collected each year for Discovery Farms sites, June 2008–October 2012.

Site

Year

Total

2008 2009 2010 2011 2012

Underwood Farm

U1 22 36 36 29 29 152

U2 18 27 40 23 4 112

U3 8 25 27 18 3 81

Dazey Farm

D1 6 2 14 8 0 30

D2 0 3 13 1 0 17

D3 0 6 19 17 5 47

Embden Farm

E1 0 3 18 4 2 27

E2 0 12 35 18 1 66

E3 0 9 44 19 7 79

For chloride, ammonia, and total nitrogen, concentrations 

decreased from U1 to U2, but were not significantly different between U2 and U3 (fig. 11). Higher chloride at U1 may 

be the result of chloride in feedlot manure caused by feed 

additives (Mullaney and others, 2009). Organic nitrogen and 

ammonia are the primary forms of nitrogen in manure, which 

likely caused higher total nitrogen (total nitrogen includes 

organic nitrogen) and ammonia concentrations at U1 (U.S. 

Environmental Protection Agency, 2013b). Some of the 

decrease in chloride, ammonia and total nitrogen concentrations between U1 and U2 likely is attributed to dilution. For 

ammonia, nitrification (conversion of ammonia to nitrite, 

and then nitrate under aerobic conditions) likely is reducing 

ammonia concentrations between U1 and U2, but contributing 

nitrate plus nitrite to U2. Different from the other constituents, nitrate plus nitrite concentrations were not significantly 

different among sites (fig. 11). Little nitrate is lost from the 

landscape through surface runoff, and nitrate is highly soluble, 

which causes it to be leached from soil or to flow through 

soil into groundwater (Randall and Mulla, 2011). In addition, 

nitrate plus nitrite is biologically available, and is affected 

by nitrification and denitrification (the conversion of nitrate 

to nitrogen gas under anoxic conditions; U.S. Environmental Protection Agency, 2013b). For nitrate plus nitrite, the 

surface runoff processes that dominated other constituents 

(dilution, settling out, vegetative uptake) were moderated by 

other processes specific to nitrate plus nitrite (high solubility, 

nitrification, and denitrification) resulting in no significant 

change in concentrations from upstream to downstream. For 

constituents other than nitrate plus nitrite, dilution, settling out 

of sediment particles, and vegetative uptake likely contributed 

to the decrease in constituent concentration from upstream to 

downstream. 

As previously discussed in the Data Presentation and 

Analysis section, although total nitrogen concentrations 

were likely underestimated, they were used to estimate the 

speciation of nitrogen in the runoff at the Discovery Farms. 

The predominant form of nitrogen at Underwood Farm was 

organic nitrogen (59 percent of total nitrogen; fig. 12), which 

is consistent with surface drainage sites at Discovery Farms in 

Wisconsin (Drummy and others, 2011). 

Consistent with constituent concentrations of chloride, 

suspended sediment, total phosphorus, and ammonia, the largest loads typically were observed at U1 and the smallest loads 

were observed at U3 (figs. 11 and 13). In contrast, for nitrate 

plus nitrite, the smallest load of about 7 pounds (lb) were 

observed at U2 and the largest load of 350 lb were observed 

at U3 (fig. 13). Consistent with annual flow volumes, for 

constituents other than nitrate plus nitrite, the smallest annual 

loads were in 2012, and the largest annual loads were in 2011 

(figs. 7 and 13). Although the largest nitrate plus nitrite loads 

generally were observed in 2010, 2011 was the year with the 

largest amount of flow volume (figs. 7 and 13). Because nitrate 

is highly soluble and easily leaches through the soil profile, 

not only does flow volume affect the loading of nitrates into 

surface drainage, but the temporal distribution of flow volume 

within a year also has an effect (Randall and Mulla, 2001). At 

Underwood Farm in 2010, April, May, and June were wetter than any of the other years (fig. 9). In spring and early 

summer, less storage capacity in the soil combined with low 

evapotranspiration losses contribute to drainage water with 

higher nitrates (Randall and Mulla, 2001). The temporal 

distribution of precipitation may have contributed to the larger 

nitrate plus nitrite loads in 2010. 

Similar to loads, with the exception of nitrate plus nitrite, 

the largest annual yields were in 2011 at the most upstream 

site (U1) and the smallest annual yields were in 2012 at the 

most downstream site (U3) (fig. 14). In 2011, annual precipitation was nearly 3 in. less than 2010 (fig. 6), but 2011 annual 

yields for chloride, total phosphorus, suspended sediment, 
Water-Quality Characteristics 19

1

10

100

1,000

Site

U1 U2 U3

0.001

0.01

0.1

1

10

100

Chloride

Median

25th percentile

75th percentile

90th percentile

10th percentile

Outlier

EXPLANATION

0.1

1

10

100

1,000

10,000

100,000

Suspended sediment

Total phosphorus

A (129)

B (104)

C (77)

A (146)

B (111) B (80)

A (146)

B (112) C (81)

 (50th percentile) 

Concentration, in milligrams per liter

Reporting level

Reporting level

Number of values—Distributions associated 

with the same letter on the same graphs 

are not significantly (alpha less than 0.01)

different

A (146)

Figure 11. Distribution of constituent concentrations at Underwood Discovery Farms, North Dakota, 2008–2012.
20 Water-Quality Characteristics in Runoff for Three Discovery Farms in North Dakota, 2008–12

0.1

1

10

100

1,000

Concentration, in milligrams per liter as nitrogen

0.01

0.1

1

10

100

Total nitrogen

0.01

0.1

1

10

100

1,000

Ammonia

Nitrate plus nitrite

A (143)

B (110) B (80)

A (143) A (110) A (80)

A (143)

B (110)

 B (80)

Site

U1 U2 U3

Median

25th percentile

75th percentile

90th percentile

10th percentile

Outlier

EXPLANATION

 (50th percentile) 

Reporting level

Reporting level

Number of values—Distributions associated 

with the same letter on the same graphs 

are not significantly (alpha less than 0.01)

different

A (143)

Figure 11. Distribution of constituent concentrations at Underwood Discovery Farms, North Dakota, 2008–2012.—Continued
Water-Quality Characteristics 21

Ammonia as nitrogen

22 percent

Organic nitrogen

59 percent

Nitrate plus nitrite nitrogen

19 percent

Underwood

Farm

Dazey

Farm

Ammonia as nitrogen

15 percent

Organic nitrogen

54 percent

Nitrate plus nitrite nitrogen

31 percent

Figure 12. Speciation of nitrogen at Underwood and Dazey Farms, North Dakota, 2008–2012.

and ammonia were between 1 to 9 times greater than yields in 

2010. The larger yield in 2011 relates well with annual runoff 

in 2011 at Underwood Farm, which, on average, was 1.5 times 

greater than runoff in 2010 (fig. 8). Consistent with nitrate 

plus nitrite annual loads, annual nitrate plus nitrite yields were 

largest in 2010. 

Dazey Farm

Variability in concentrations among sites at Dazey Farm 

(fig. 1) was predominantly affected by local topography and 

surface-groundwater interactions. D1 and D2 are located 

towards the top of a hill, in a gully with steep sides, and 

duration of flow during a runoff event is short. In contrast, 

D3 is located at the base of the hill and seems to be affected 

by groundwater. It is likely that groundwater contributes to 

surface runoff at D3 because flow continued at D3 after flow 

stopped at the other sites, and a trickle of flow (less than 

0.001 cubic foot per second) continues throughout the summer 

(W. C. Damschen, U.S. Geological Survey, oral commun., 

2014). The steepness of the hill and side channels at D1 and 

D2 caused mud flows during high flows that complicated 

efforts to maintain and operate the flumes resulting in fewer 

samples being collected at D1 and D2 (table 4). Data for D2 

are presented, but because there are few samples and some of 

the samples were affected by mud flows, general comparisons 

were made between D1 (closest site to the feeding area) and 

D3 (farthest site from the feeding area). The median chloride 

concentration was significantly higher at D3 than D1 (fig. 15) 

ranging from 3.53 mg/L at D1 to 73.2 mg/L at D3. Higher 

concentrations of chloride at D3 is likely from saline groundwater contribution, but also could be caused by weathering of surficial materials and soils (Mullaney and others, 

2009). Suspended sediment, total phosphorus, and ammonia 

concentrations were significantly lower at D3 than at D1 

(fig. 15) likely because of dilution from surrounding crop land, 

and the location of D3 at the base of the hill allows sediment 

and associated particulate phosphorus to settle out. Nitrate 

plus nitrite and total nitrogen median concentrations were not 

significantly different between D1 and D3 likely because of 

surface-groundwater interaction, nitrification, and denitrification. Similar to Underwood Farm, the predominant form of 

nitrogen at Dazey Farm was organic nitrogen (fig. 12). 

For suspended sediment, total phosphorus, and ammonia, 

annual loads and yields at D3 were larger in 2010 than 2011 

(figs. 13 and 14), which was consistent with the pattern in 

precipitation and runoff (figs. 6 and 8). The sediment load was 

three times larger in 2010 than in 2011, but runoff only was 

1.5 times greater in 2010 than 2011. The much larger sediment load in 2010 was the result of a single runoff event on 

May 24, 2010. On May 24, the daily mean concentration for 

suspended sediment was 10,300 mg/L. For chloride and nitrate 

plus nitrite, the largest annual loads did not coincide with the 

year of largest runoff, which may be caused by groundwater 

interaction with the surface runoff. Annual loads and yields 

for chloride were nearly the same in 2010 and 2011 (figs. 13 

and 14). For nitrate plus nitrite, annual loads and yields were 

larger in 2011 than 2010 (figs. 13 and 14). 

Embden Farm

Among sites at Embden Farm (fig. 1), water-quality patterns emerged, which reflected differences between surface 

drainage and subsurface drainage systems. The following 

differences between surface and subsurface drainage systems 

at Embden Farm were similar to those documented by Neely 

and Baker (1989): (1) ammonia concentrations were similar between surface drainage and subsurface drainage, (2) 
22 Water-Quality Characteristics in Runoff for Three Discovery Farms in North Dakota, 2008–12

1

10

100

1,000

10,000

100,000

2009 2010 2011 2012 2010 2011 2010 2011 2012

0.1

1

10

100

1,000

10,000

Annual load, in pounds 

100

1,000

10,000

100,000

1,000,000

0.01

0.1

1

10

100

1,000

10,000

2009 2010 2011 2012 2010 2011 2010 2011 2012

0.01

0.1

1

10

100

1,000

10,000

100,000

Chloride

Suspended sediment Total phosphorus

Ammonia Nitrate plus nitrite

No data 

available

U1 

U2 

U3 

E1

E2

D3 E3

EXPLANATION

Underwood Farm

Dazey Farm

Embden Farm

Underwood

Farm

Dazey

Farm

Embden

Farm

Year

Underwood

Farm

Dazey

Farm

Embden

Farm

Year

Figure 13. Annual loads for Discovery Farms in North Dakota, 2009–2012.
Water-Quality Characteristics 23

0.01

0.1

1

10

100

1,000

2009 2010 2011 2012 2010 2011 2010 2011 2012

0.001

0.01

0.1

1

10

Annual yield, in pounds per acre

0.01

0.1

1

10

100

1,000

10,000

0.001

0.01

0.1

1

10

100

2009 2010 2011 2012 2010 2011 2010 2011 2012

0.0001

0.001

0.01

0.1

1

10

100

1,000

Chloride

Suspended sediment Total phosphorus

Ammonia Nitrate plus nitrite

Underwood

Farm

Dazey

Farm

Embden

Farm

Year

Underwood

Farm

Dazey

Farm

Embden

Farm

Year

No data 

available

U1 

U2 

U3 D3 E1

EXPLANATION

Underwood Farm

Dazey Farm Embden Farm

Figure 14. Annual yields for Discovery Farms in North Dakota, 2009–2012.
24 Water-Quality Characteristics in Runoff for Three Discovery Farms in North Dakota, 2008–12

Site

D1 D2 D3

1

10

100

1,000

0.001

0.01

0.1

1

10

1

10

100

1,000

10,000

100,000

1,000,000

Chloride

Suspended sediment

Total phosphorus

Median

25th percentile

75th percentile

90th percentile

10th percentile

Outlier

EXPLANATION

 (50th percentile) 

A (26) B (17) C (41)

A (25)

A (17) B (37)

A (28)

A (16)

B (43)

Concentration, in milligrams per liter

Reporting level

Reporting 

level

Number of values—Distributions associated 

with the same letter on the same graphs 

are not significantly (alpha less than 0.01)

different

A (26)

Figure 15. Distribution of constituent concentrations at Dazey Farm, North Dakota, 2009–2012.
Water-Quality Characteristics 25

0.01

0.1

1

10

100

0.01

0.1

1

10

100

Site

D1 D2 D3

0.1

1

10

100

Total nitrogen

Ammonia

Nitrate plus nitrite

Median

25th percentile

75th percentile

90th percentile

10th percentile

Outlier

EXPLANATION

 (50th percentile) 

A (23)

B (16)

C (36)

A (25)

B (16)

A (38)

AB (25)

A (16)

 B (38)

Concentration, in milligrams per liter as nitrogen

Reporting level

Reporting level

Number of values—Distributions associated 

with the same letter on the same graphs 

are not significantly (alpha less than 0.01)

different

A (23)

Figure 15. Distribution of constituent concentrations at Dazey Farm, North Dakota, 2009–2012.—Continued
26 Water-Quality Characteristics in Runoff for Three Discovery Farms in North Dakota, 2008–12

phosphorus concentrations generally were higher in surface 

drainage, and (3) nitrate nitrogen concentrations in subsurface 

drainage were 10 to 100 times higher than surface drainage. 

For Embden Farm, ammonia concentrations ranged from less 

than 0.03 to 1.95 mg/L with no statistically significant difference among sites (fig. 16). Total phosphorus concentrations 

were significantly higher at surface drainage site E1 with a 

median concentration of 0.19 mg/L compared with a median 

concentration of 0.021 mg/L at E2 (fig. 16). Nitrate plus nitrite 

concentrations and total nitrogen concentrations were 10 to 

100 times higher at E2 and E3 compared to E1, and differences were statistically significant. The maximum nitrate plus 

nitrite concentration at E1 of 0.89 mg/L is less than the minimum concentration of 0.95 mg/L at E2. Similar to nitrate plus 

nitrite, chloride concentrations at E2 and E3 were significantly 

higher than at E1 and ranged from less than 3.00 mg/L at E1 

to 41.4 mg/L at E3 (fig. 16). High solubility allows nitrate plus 

nitrite to readily flow through the soil and into tile lines (U.S. 

Environmental Protection Agency, 2013), but groundwater 

also may be contributing to higher nitrate plus nitrite and chloride concentrations at the subsurface drainage sites. 

The speciation of nitrogen between the surface drainage site and subsurface drainage sites was distinctly different 

(fig. 17). The predominant form of nitrogen at E1 was organic 

nitrogen (68 percent), which is consistent with surface drainage sites at Underwood and Dazey Farms (fig. 12). For the 

subsurface drainage sites, the predominant form of nitrogen 

was nitrate plus nitrite (93 percent), which is consistent with 

subsurface drainage sites at Discovery Farms in Wisconsin 

(University of Wisconsin-Extension Discovery Farms, 2013). 

At the Embden Farm, during the wet years of 2010 and 

2011, the subsurface drainage sites (E2 and E3) had the highest flow volumes and the largest annual loads (fig. 7, fig. 13). 

In 2010 and 2011, annual loads of chloride, ammonia, and 

nitrate plus nitrite at the subsurface drainage sites were 10 to 

1,000 times greater than annual loads at the surface drainage 

site (E1). Total phosphorus concentrations were significantly 

lower at E2 and E3 compared with E1 (fig. 16), but because of 

1

10

100

Site

E1 E2 E3

0.001

0.01

0.1

1

10

Concentration, in milligrams per liter

Chloride

Total phosphorus

Median

25th percentile

75th percentile

90th percentile

10th percentile

Outlier

EXPLANATION

 (50th percentile) 

A (22)

B (74) B (62)

A (27)

B (63) C (77)

Reporting level

Reporting level

Number of values—Distributions associated 

with the same letter on the same graphs 

are not significantly (alpha less than 0.01)

different

A (27)

Figure 16. Distribution of constituent concentrations at Embden Farm, North Dakota, 2009–2012.
Water-Quality Characteristics 27

0.01

0.1

1

10

100

0.01

0.1

1

10

Ammonia

Nitrate plus nitrite

Site

E1 E2 E3

0.1

1

10

100

Total nitrogen

A (22)

A (60) A (75)

A (22)

B (60)

C (75)

A (22)

B (60) C (75)

Median

25th percentile

75th percentile

90th percentile

10th percentile

Outlier

EXPLANATION

 (50th percentile) 

Number of values—Distributions associated 

with the same letter on the same graphs 

are not significantly (alpha less than 0.01)

different

A (22)

Concentration, in milligrams per liter as nitrogen

Reporting level

Reporting level

Figure 16. Distribution of constituent concentrations at Embden Farm, North Dakota, 2009–2012.—Continued
28 Water-Quality Characteristics in Runoff for Three Discovery Farms in North Dakota, 2008–12

Nitrate plus nitrite nitrogen

 93 percent

Embden 2 and 3

Nitrate plus nitrite nitrogen

 25 percent

Organic nitrogen

68 percent

Organic nitrogen

5.5 percent

Ammonia as nitrogen

7 percent

Embden 1

Ammonia as nitrogen

1.5 percent

Figure 17. Speciation of nitrogen at Embden Farm, North Dakota, 2009–2012.

higher flow volumes, in 2010 and 2011, total phosphorus loads 

were larger at E2 and E3 than E1. Other than total phosphorus, 

loads generally were largest in 2010, which corresponded to 

the year of highest precipitation and flow volume. In contrast, 

during the dry year of 2012 (fig. 6), total phosphorus and 

ammonia loads were larger at the surface drainage site (E1) 

than at subsurface drainage sites (E2 and E3; fig. 16). 

For Embden Farm, yields were computed for the surface drainage site, E1. For chloride, yields were less than 

1 lb/acre with the largest yield in 2010 (fig. 14). For total 

phosphorus and nitrate plus nitrite, the largest annual yield 

was in 2011, which is consistent with the year with the highest 

runoff (figs. 8 and 14). Total phosphorus and ammonia yields 

varied little from year to year and generally were less than 

0.1 lb/acre.

Consistent patterns in water quality emerged at each 

individual farm, but similarities among farms also were 

observed. Suspended sediment, total phosphorus, and ammonia concentrations generally decreased downstream from 

feeding areas, and were primarily affected by surface runoff 

processes such as dilution, settling out of sediment, or vegetative uptake. Because surface runoff affects these constituents, 

increased annual surface runoff tended to result in increased 

loads and yields. No significant change in nitrate plus nitrite 

concentrations were observed downstream from feeding areas 

because additional processes such as high solubility, nitrification, denitrification, and surface-groundwater interaction 

affect nitrate plus nitrite. For nitrate plus nitrite, increases 

in annual runoff did not consistently relate to increases in 

annual loads and yields. It appears that temporal distribution 

of precipitation and surface-groundwater interaction affected 

nitrate plus nitrite loads and yields. For surface drainage sites 

(U1-3, D1-3, and E1), the predominant form of nitrogen was 

organic nitrogen whereas for subsurface drainage sites (E2 and 

E3), the predominant form of nitrogen was nitrate plus nitrite 

nitrogen. 

Summary

North Dakota has implemented several policies with 

the goal of minimizing runoff from animal feeding operations; however, little data have been collected to evaluate the 

effects of runoff from feeding operations on water quality 

or improvements in water quality resulting from changes in 

animal feeding operation practices. In response to this lack of 

data, the U.S. Geological Survey, in cooperation with North 

Dakota State University Agriculture Research Extension 

and in collaboration with North Dakota State Department of 

Health, North Dakota State Water Commission, U.S. Environmental Protection Agency, and several agricultural producers 

helped organize a Discovery Farms program in North Dakota 

in 2007. Discharge measurements and water-quality samples 

collected at the three Farms, Underwood, Dazey, and Embden, 

were used to describe water-quality characteristics in runoff, 

and compute estimates of annual loads and yields for selected 

constituents from spring 2008 through fall 2012.

At Underwood Farm, concentrations generally decreased 

from upstream to downstream because of proximity to the 

feedlot and grassy depressions located between sites. With 

the exception of nitrate plus nitrite, a statistically significant 

decrease in concentration from upstream to downstream generally was observed. At downstream sites, less concentrated 

runoff from surrounding crop land likely caused some dilution. 

In the grassy depressions between sites, particulate phosphorus 

likely was removed from sediment settling out, and dissolved 

phosphorus likely was removed by vegetation. For nitrate plus 

nitrite, the surface runoff processes that dominated other constituents (dilution, settling out, vegetative uptake) were moderated by other processes specific to nitrate plus nitrite (high 

solubility, nitrification, and denitrification) resulting in no 

significant change in concentrations from upstream to downstream. For constituents other than nitrate plus nitrite, dilution, 
Summary 29

settling out of sediment particles, and vegetative uptake likely 

contributed to the decrease in constituent concentration from 

upstream to downstream. The predominant form of nitrogen 

at Underwood Farm was organic nitrogen (59 percent of total 

nitrogen), which is consistent with surface drainage sites at 

Discovery Farms in Wisconsin. 

At Underwood Farm, consistent with constituent concentrations of chloride, suspended sediment, total phosphorus, 

and ammonia, the largest loads typically were observed at 

the upstream site, and the smallest loads were observed at the 

downstream site. Consistent with annual flow volumes, for 

constituents other than nitrate plus nitrite, the smallest annual 

loads were in 2012, and the largest annual loads were in 2011. 

Although the largest nitrate plus nitrite loads generally were 

observed in 2010, 2011 was the year with the largest amount 

of flow volume. The temporal distribution of precipitation may 

have contributed to the larger nitrate plus nitrite loads in 2010. 

Similar to loads, with the exception of nitrate plus nitrite, 

the largest annual yields at Underwood Farm were in 2011 at 

the most upstream site, and the smallest annual yields were 

in 2012 at the most downstream site. The larger yield in 2011 

relates well with annual runoff in 2011 at Underwood Farm, 

which, on average, was 1.5 times greater than runoff in 2010. 

Consistent with nitrate plus nitrite annual loads, annual nitrate 

plus nitrite yields were largest in 2010. 

Variability in concentrations among sites at Dazey Farm 

was predominantly affected by local topography and surfacegroundwater interactions. Chloride concentrations were highest at the site farthest downstream likely because of groundwater contribution. Suspended sediment, total phosphorus, 

and ammonia concentrations were significantly lower at the 

downstream site likely because of dilution and settling out of 

sediment. Nitrate plus nitrite concentrations were not significantly different from upstream to downstream likely because 

surface-groundwater interaction, nitrification, and denitrification. Similar to Underwood Farm, the predominant form of 

nitrogen at Dazey Farm was organic nitrogen. 

For suspended sediment, total phosphorus, and ammonia, 

annual loads and yields at Dazey Farm were larger in 2010 

than 2011, which was consistent with the pattern in precipitation and runoff. The sediment load was three times greater 

in 2010 than in 2011, but runoff only was 1.5 times larger in 

2010 than 2011. The much larger sediment load in 2010 was 

the result of a single runoff event on May 24, 2010. On May 

24, the daily mean concentration for suspended sediment was 

10,300 mg/L. For chloride and nitrate plus nitrite, the largest 

annual loads did not coincide with the year of largest runoff, 

which may be caused by groundwater interaction with the 

surface runoff. 

Among sites at Embden Farm, water-quality patterns 

emerged, which reflected differences between surface drainage 

and subsurface drainage systems, and similar differences have 

been documented in other reports. Unlike other constituents, 

there were no statistically significant differences in ammonia 

concentrations among sites. Total phosphorus concentrations 

were significantly higher at the surface drainage site. Nitrate 

plus nitrite concentrations and total nitrogen concentrations 

were 10 to 100 times higher at subsurface drainage sites 

compared to the surface drainage site, and differences were 

statistically significant. Similar to nitrate plus nitrite, chloride concentrations were significantly higher at subsurface 

drainage sites than the surface drainage site. High solubility 

allows nitrate plus nitrite to readily flow through the soil and 

into tile lines, but groundwater also may be a contributing to 

higher nitrate plus nitrite and chloride concentrations at the 

subsurface drainage sites. The speciation of nitrogen between 

the surface drainage site and subsurface drainage sites was 

distinctly different. The predominant form of nitrogen at the 

surface drainage site was organic nitrogen (68 percent), which 

is consistent with surface drainage sites at Underwood and 

Dazey Farms. For the subsurface drainage sites, the predominant form of nitrogen was nitrate plus nitrite (93 percent), 

which is consistent with subsurface drainage sites at Discovery 

Farms in Wisconsin. 

At the Embden Farm, during the wet years of 2010 

and 2011, the subsurface drainage sites had the highest flow 

volumes and the largest annual loads. In 2010 and 2011, 

annual loads of chloride, ammonia, and nitrate plus nitrite at 

the subsurface drainage sites were 10 to 1,000 times greater 

than annual loads at the surface drainage site. Other than total 

phosphorus, loads generally were largest in 2010, which corresponded to the year of highest precipitation and flow volume. 

Consistent patterns in water quality emerged at each 

individual farm, but similarities among farms also were 

observed. Suspended sediment, total phosphorus, and ammonia concentrations generally decreased downstream from 

feeding areas and were primarily affected by surface runoff 

processes such as dilution, settling out of sediment, or vegetative uptake. Because surface runoff affects these constituents, 

increased annual surface runoff tended to result in increased 

loads and yields. No significant change in nitrate plus nitrite 

concentration were observed downstream from feeding areas 

because additional processes such as high solubility, nitrification, denitrification, and surface-groundwater interaction affect 

nitrate plus nitrite. For nitrate plus nitrite, increases in annual 

runoff did not consistently relate to increases in annual loads 

and yields. It appears that temporal distribution of precipitation and surface-groundwater interaction affected nitrate plus 

nitrite loads and yields. For surface drainage sites, the primary 

form of nitrogen was organic nitrogen, whereas the primary 

form of nitrogen was nitrate plus nitrite nitrogen for subsurface drainage sites. 
30 Water-Quality Characteristics in Runoff for Three Discovery Farms in North Dakota, 2008–12

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Publishing support provided by: 

Rolla Publishing Service Center

For more information concerning this publication, contact:

Director, USGS North Dakota Water Science Center

821 East Interstate Avenue

Bismarck, North Dakota 58503

(701) 250–7400

Or visit the North Dakota Water Science Center Web site at: 

http://nd.water.usgs.gov/

Nustad and others—Water-Quality Characteristics in Runoff for Three Discovery Farms in North Dakota, 2008–12—SIR 2014–5212

ISSN 2328-0328 (online)

http://dx.doi.org/10.3133/sir20145212