U.S. Department of the Interior

U.S. Geological Survey

Scientific Investigations Report 2012–5014

Prepared in cooperation with the City of Middleton, Wisconsin

Evaluation of the Effects of City of Middleton StormwaterManagement Practices on Streamflow and Water-Quality 

Characteristics of Pheasant Branch, Dane County, 

Wisconsin, 1975–2008
Cover photographs:

(Upper left) Pheasant Branch Creek at confluence pond, photograph by Warren A. Gebert

(Upper right) Pheasant Branch Creek at U.S. Geological Survey streamflow-gaging station 

(05427948), photograph by Herbert S. Garn

(Lower left) Repaired channel in middle reach of Pheasant Branch Creek, photograph by 

Warren A. Gebert

(Lower right) Pheasant Branch Creek upstream of marsh, photograph by Herbert S. Garn
Evaluation of the Effects of City of Middleton 

Stormwater-Management Practices on 

Streamflow and Water-Quality 

Characteristics of Pheasant Branch, 

Dane County, Wisconsin, 1975–2008

By Warren A. Gebert, William J. Rose, and Herbert S. Garn

Prepared in cooperation with the City of Middleton, Wisconsin

Scientific Investigations Report 2012–5014

U.S. Department of the Interior

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

KEN SALAZAR, Secretary

U.S. Geological Survey

Marcia K. McNutt, Director

U.S. Geological Survey, Reston, Virginia: 2012

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Although this report is in the public domain, permission must be secured from the individual copyright owners to 

reproduce any copyrighted materials contained within this report.

Suggested citation:

Gebert, W.A., Rose, W.J., and Garn, H.S., 2012, Evaluation of the effects of Middleton’s stormwater-management 

activities on streamflow and water-quality characteristics of Pheasant Branch, Dane County, Wisconsin1975–2008: 

U.S. Geological Survey Scientific Investigations Report 2012–5014, 27 p. plus appendixes.
iii

Contents

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

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

Stormwater Runoff-Management Practices.............................................................................................4

Stormwater-Management Structures...............................................................................................4

Nonstructural Best Management Practices ...................................................................................7

Changes in Streamflow Characteristics ....................................................................................................8

Changes in Water-Quality Characteristics..............................................................................................14

Suspended Sediment and Total Phosphorus .................................................................................15

Spatial Variability of Suspended Sediment in Pheasant Branch in 2008...................................19

Specific Conductance and Chloride Monitoring, 2007–8.............................................................20

Discussion and Conclusions......................................................................................................................26

References Cited..........................................................................................................................................27

Appendixes 1 and 2......................................................................................................................................28

Appendix 1. Storm Water Runoff Control Ordinance Summary (from City of Middleton 

Storm Water Control Ordinance, chap 26.0, June 2008)..........................................................29

Storm Water Discharge Quality........................................................................................................29

Sediment Control .......................................................................................................................29

Storm Water Discharge Quantity .....................................................................................................29

Runoff Rate Control ...................................................................................................................29

Infiltration.............................................................................................................................................29

Appendix 2. Erosion Control Summary (from City of Middleton Erosion Control Ordinance, 

chap. 28, June 2008).......................................................................................................................30

28.03 Purpose.......................................................................................................................................30

28.05 Requirements for Erosion Control Plan.................................................................................30

Figures

1. Map showing the Pheasant Branch watershed in Dane County, Wis. ...............................3

2. Photograph showing Confluence Pond on Pheasant Branch in Middleton, Wis., 

in 2008, with a view of the outlet structure...............................................................................5

3. Photograph showing Northlake Pond water-quality detention basin in Middleton, 

Wis., in 2008 ...................................................................................................................................5

4. Photograph showing infiltration basin at retail dealership on Airport Road in 

Middleton, Wis., in 2008...............................................................................................................6

5. Photograph showing bioretention facility at a commercial parking lot in Middleton, 

Wis., in 2008 ...................................................................................................................................6

6. Photograph showing a residential rain garden in Middleton, Wis. .....................................7

7. Graph showing annual streamflow and baseflow at Pheasant Branch at Middleton, 

Wis., 1975–2008 .............................................................................................................................8

8. Graph showing annual precipitation at Madison, Wis., 1975–2008 .....................................9

9. Graph showing cumulative annual streamflow at Pheasant Branch at Middleton, 

Wis., 1975–2008 ...........................................................................................................................10
iv

10. Graph showing comparison of annual streamflow of Pheasant Branch at 

Middleton, Wis. and annual precipitation at Madison, Wis., 1975–2008...........................10

11. Graph showing annual flood-peak discharges at Pheasant Branch at Middleton, 

Wis., 1975–2008 ...........................................................................................................................11

12. Graph showing comparison of annual flood peaks of Pheasant Branch at 

Middleton with annual flood peaks at three nearby streams at three gaging 

stations in Wisconsin for 1976–2008........................................................................................13

13. Graph showing comparison of annual flood peak discharges in cubic feet per 

second per square mile at four gaging stations in Wisconsin for 1976–2008: 

Pheasant Branch at Middleton, Black Earth Creek at Black Earth, Yahara River 

at Windsor, and Spring Harbor Storm Sewer at Madison ...................................................15

14. Graph showing annual suspended-sediment loads for Pheasant Branch at 

Middleton, Wis., 1978–2008.......................................................................................................15

15. Graph showing annual flow volumes and annual average suspended-sediment 

concentrations for Pheasant Branch at Middleton, Wis., 1978–2008................................16

16. Graph showing annual phosphorus loads for Pheasant Branch at Middleton, 

Wis., 1993, 1995–2008 .................................................................................................................17

17. Graph showing annual flow volumes and annual average total phosphorus 

concentrations for Pheasant Branch at Middleton, Wis., 1993, 1995–2008......................17

18. Graph showing annual flow volumes, suspended-sediment loads, and total 

phosphorus loads for Pheasant Branch at Middleton, Wis., 1993–2008 ...........................18

19. Photograph showing Pheasant Branch upstream from marsh showing sand 

deposition, channel widening, and overflow channels entering marsh ...........................22

21. Graph showing measured and estimated chloride concentrations of Pheasant 

Branch at Middleton, Wis. during February through September 2007 (A) and 

October 2007 through April 2008 (B)........................................................................................23

20. Graph showing regression relation of specific conductance and chloride 

concentration at Pheasant Branch at Middleton, Wis.........................................................23

22. Graph showing daily and monthly salt loads, expressed as sodium chloride, at 

Pheasant Branch at Middleton, Wis. for February 2007–April 2008...................................24

Tables

1. Average annual baseflow at four sites in the Pheasant Branch watershed, 

Dane County, Wisconsin..............................................................................................................9

2. Flood-peak discharges for various recurrence intervals at Pheasant Branch at 

Middleton, Wis., 1975–2008.......................................................................................................11

3. Comparison of flood peak discharges based on simulated annual peak discharges 

and actual annual flood peak discharges ..............................................................................12

4. Comparison of changes in flood peak discharge values at three U.S. Geological 

Survey streamflow-gaging stations near Middleton, Wis. ..................................................14

5. Comparison of annual sediment and phosphorus loads for three major streams 

contributing to Lake Mendota, Wis., for the periods 1993, 1995–2001, and 2002–8.........19

6. Comparison of annual suspended sediment load for five U.S. Geological Survey 

streamflow-gaging stations on Pheasant Branch near Middleton, Wis., 1978–81..........19

 7. Summary of suspended-sediment data collected at five U.S. Geological Survey 

stations on Pheasant Branch in Middleton, Wis., during 2008 ...........................................21

8. Summary of monthly chloride and sodium chloride loads at Pheasant Branch at 

Middleton, Wis. (station 05427948) for February 2007–April 2008.......................................25
v

Conversion Factors, Abbreviations, and Datum

Inch-pound to SI

Multiply By To obtain

Length

inch (in) 2.54 centimeter (cm)

inch (in) 25.4 millimeter (mm)

foot (ft) .3048 meter (m)

mile (mi) 1.609 kilometer (km)

Area

acre 4,047 square meter (m2

)

acre .4047 hectare (ha)

acre .004047 square kilometer (km2

)

square mile (mi2

) 259.0 hectare (ha)

square mile (mi2

) 2.590 square kilometer (km2) 

Volume

cubic foot (ft3

) .2832 cubic meter (m3)

Flow rate

cubic foot per second (ft3

/s) .02832 cubic meter per second (m3/s)

cubic foot per second per square 

mile [(ft3

/s)/mi2] .01093 cubic meter per second per square kilometer [(m3/s)/km2]

Mass

pound, avoirdupois (lb) .4536 kilogram (kg) 

pound per year (lb/yr) .4536 kilogram per year (kg/yr)

ton, short (2,000 lb) .9072 megagram (Mg) 

ton, long (2,240 lb) 1.016 megagram (Mg) 

ton per day (ton/d) .9072 metric ton per day

ton per year (ton/yr) .9072 metric ton per year

SI to inch-pound

Multiply By To obtain

Length

millimeter .3937 inch (in)

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

°F=(1.8×°C)+32

Specific conductance is given in microsiemens per centimeter at 25 degrees Celsius (μS/cm at 

25 °C).

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

or micrograms per liter (μg/L).

Evaluation of the Effects of City of Middleton StormwaterManagement Practices on Streamflow and Water-Quality 

Characteristics of Pheasant Branch, Dane County, 

Wisconsin, 1975–2008

By Warren A. Gebert, William J. Rose, and Herbert S. Garn

Abstract

Few long-term data sets are available for evaluating the 

effects of urban stormwater-management practices. Over 30 

years of data are available for evaluating the effectiveness 

of such practices by the city of Middleton, Wis. Analysis 

of streamflow and water-quality data collected on Pheasant 

Branch, demonstrates the relation between the changes in the 

watershed to the structural and nonstructural best management 

practices put in place during 1975–2008. A comparison of the 

data from Pheasant Branch with streamflow and water-quality 

data (suspended sediment and total phosphorus) collected at 

other nearby streams was made to assist in the determination 

of the possible causes of the changes in Pheasant Branch. 

Based on 34 years of streamflow data collected at the 

Pheasant Branch at Middleton streamflow-gaging station, 

flood peak discharges increased 37 percent for the 2-year flood 

and 83 percent for the 100-year flood. A comparison of data 

for the same period from an adjacent rural stream, Black Earth 

at Black Earth had a 43 percent increase in the 2-year flood 

peak discharge and a 140-percent increase in the 100-year 

flood peak discharge. Because the flood peak discharges on 

Pheasant Branch have not increased as much as Black Earth 

Creek it appears that the stormwater management practices 

have been successful in mitigating the effects of urbanization. 

Generally urbanization results in increased flood peak discharges. The overall increase in flood peak discharges seen in 

both streams probably is the result of the substantial increase 

in precipitation during the study period. Average annual runoff 

in Pheasant Branch has also been increasing due to increasing 

average annual precipitation and urbanization. 

The stormwater-management practices in Middleton have 

been successful in decreasing the suspended-sediment and 

total phosphorus loads to Lake Mendota from the Pheasant 

Branch watershed. These loads decreased in spite of increased 

annual runoff and flood peaks, which are often expected to

produce higher sediment and phosphorus loads. The biggest 

decreases in sediment and phosphorus loads occurred after 

2001 when a large detention pond, the Confluence Pond, 

began operation. Since 2001, the annual suspended-sediment 

load has decreased from 2,650 tons per year to 1,450 tons per 

year for a 45-percent decrease. The annual total phosphorus 

load has decreased from 12,200 pounds per year to 6,300 

pounds per year for a 48-percent decrease. A comparison of 

Pheasant Branch at Middleton with two other streams, Spring 

Harbor Storm Sewer and Yahara River at Windsor, that drain 

into Lake Mendota shows that suspended-sediment and total 

phosphorus load decreases were greatest at Pheasant Branch 

at Middleton. Prior to the construction of the Confluence 

Pond, annual suspended-sediment yield and total phosphorus yield from Pheasant Branch watershed was the largest of 

the three watersheds. After 2001, suspended-sediment yield 

was greatest at Spring Harbor Storm Sewer, and lowest at 

Yahara at Windsor; annual total phosphorus yield was greater 

at Yahara River at Windsor than that of Pheasant Branch. The 

stormwater-quality plan for Middleton shows that the city 

has met the present State of Wisconsin Administrative Code 

chap. NR216/NR151 requirements of reducing total suspended 

solids by 20 percent for the developed area in Middleton. In 

addition, the city already has met the 40-percent reduction in 

total suspended solids required by 2013. 

Snow and ice melt runoff from road surfaces and parking 

lots following winter storms can effect water quality because 

the runoff contains varying amounts of road salt. To evaluate 

the effect of road deicing on stream water quality in Pheasant 

Branch, specific conductance and chloride were monitored 

during two winter seasons. The maximum estimated concentration of chloride during the monitoring period was 931 

milligrams per liter, which exceeded the U.S. Environmental 

Protection Agency acute criterion of 860 milligrams per liter. 

Chloride concentrations exceeded the U.S. Environmental 

Protection Agency chronic criterion of 230 milligrams per liter 

for at least 10 days during February and March 2007 and for 
2 Effects of Middleton Stormwater-Management Practices on Streamflow and Water Quality, Pheasant Branch

45 days during the 2007–8 winter seasons. The total sodium 

chloride load for the monitoring period was 1,720 tons and the 

largest sodium chloride load occurred in March and April of 

each year.

Introduction

The purpose of this report is to evaluate the effectiveness 

of Middleton’s stormwater-management practices over the 

period 1975–2008 on Pheasant Branch by analyzing streamflow and water-quality data collected on Pheasant Branch. The 

data were evaluated in relation to structural and nonstructural 

best management practices (BMPs) that have been put in 

place. Pheasant Branch data were compared with streamflow 

and water-quality data collected at other streams in the area 

to determine the possible causes of the changes in Pheasant 

Branch. 

Pheasant Branch (fig. 1) is a tributary to Lake Mendota 

in Dane County in south-central Wisconsin. Much of its 

24.5-square mile (mi2) watershed is within the city of Middleton. The watershed consists of rolling hills in the uplands, 

some of which are cultivated; heavily cultivated fields in 

the glacial lowlands or outwash plains; and urban area that 

includes residential, commercial and light industrial development in the lower part of the watershed in Middleton. The 

upper part of the watershed consists of the North Fork Pheasant Branch basin (11.51 mi2

) and the South Fork Pheasant 

Branch basin (6.2 mi2). The land use in the North Fork Pheasant Branch basin is mainly agricultural, with some residential 

and commercial development, and the South Fork Pheasant 

Branch basin is about 80 percent urbanized with commercial 

and residential development in the cities of Madison and 

Middleton.

The Pheasant Branch watershed is rapidly urbanizing as 

indicated by more than doubling of the population of Middleton since 1970, increasing from 8,266 in 1970, to 11,851 

in 1980, to 16,129 in 2000 (Steuer and Hunt, 2001), and to 

17,442 in 2010 (U.S. Census Bureau, 2011). In the 1970s, the 

city was concerned about urbanization causing increased flood 

peaks and increased water volumes resulting in increased 

channel erosion and increased pollutant loading to Lake 

Mendota. Studies by Grant and Goddard (1980) and Krug and 

Goddard (1986) documented these concerns and the adverse 

effects of urbanization on the stream channel. More subtly, 

increased urbanization could reduce recharge to the local 

groundwater system, resulting in decreased baseflow adversely 

affecting downgradient ecosystems such as the Pheasant 

Branch Marsh (Steuer and Hunt, 2001) and nearby streams 

like Black Earth Creek

In the early 1960s, the city of Middleton was concerned 

about the possible negative effects of urbanization and, in 

particular, the increased channel erosion of Pheasant Branch. 

Another important concern was the sediment and phosphorus 

load into Lake Mendota and the long term health of the lake. 

Lake Mendota is part of the five-lake system in Dane County 

that provides valuable recreational opportunities in the area. 

Lake Mendota has extensive algal blooms every year that have 

caused beach closings and other missed recreational opportunities. Local lake managers believe Pheasant Branch contributed the largest phosphorus yield of the three main streams 

tributary to Lake Mendota.

 To address these concerns, the Middleton Water 

Resource Commission (MWRC) was formed in 1970 to protect and enhance the water resources of Middleton. Because 

Middleton was rapidly urbanizing, steps to document and 

minimize some of the impacts on the water resources were 

required; thus, several important actions were initiated in the 

1970s. 

One of the first actions by MWRC was the development 

in 1979 of a stormwater runoff-control ordinance (City of 

Middleton, 2008) that would prevent any development from 

increasing flood peaks due to the increased impervious area 

associated with development. The ordinance was the first in 

the State to address this issue, and it has been used as a model 

by many municipalities since then. The Middleton ordinance 

has been modified several times since 1979, most recently in 

2009; the modifications addressed the loss of recharge to the 

groundwater system and the need to reduce the pollutant load 

entering Lake Mendota. Since the ordinance was enacted, 

more than 100 structural stormwater-management facilities 

have been constructed, and additional facilities are being 

planned or constructed. Key components of the Storm Water 

Control Ordinance are summarized in Appendix 1. In about 

1979, Middleton also adopted an Erosion Control Ordinance 

(City of Middleton, 2008) to prevent accelerated soil erosion 

from construction sites, and the key components are summarized in Appendix 2.

A second important action by the MWRC was the establishment of a streamflow-gaging station on Pheasant Branch in 

cooperation with the U.S. Geological Survey (USGS) in 1974. 

The station, Pheasant Branch at Middleton (USGS number 

05427948), is located immediately downstream of the confluence of the North and South Fork Pheasant Branch tributaries 

and near U.S. Highway 12 and Parmenter Street. The drainage 

area at the gaging station is 18.3 square miles of which 1.2 

square miles is noncontributing. Therefore the station monitors 

runoff from 17.1 mi2

 of the watershed. Only streamflow data 

were collected initially, but an automatic pump sampler was 

installed in December 1977 to meet the need for additional 

information on sediment and water-quality characteristics 

of the stream. Suspended-sediment data have been collected 

since then, and phosphorus data have been collected since 

1993. In addition, a recording rain gage was installed at the 

station in October 1987. The station provides one of the longest records of concurrent streamflow, sediment, and nutrient 

data in the State.
Introduction 3

Lake Mendota

Airport Rd.

Schneider Rd.

Beltline

Old Sauk Rd.

Vosen Rd.

Ripp Rd.

Balzer Rd.

Junction Rd.

Pleasant View Rd.

Century Ave.

Pahl Rd.

Pheasant Branch Rd.

Elderberry Rd. Capitol View

Mineral Point Rd.

Century

Airport Rd.

Church Rd.

K

Q

S

Riles Rd.

West

Hwy.

Ave

Confluence Pond

South Pond

Esser Pond

NORTH FORK BASIN

SOUTH FORK BASIN

North Fork Pheasant Branch

South Fork Pheasant Branch

Northlake

Ponds

Pheasant 

Branch

Marsh

Pheasant Branch

05427952

05427950

05427948

05427943

054279501

054279449

054279465

054279435

0 1 2 MILES

0 1 2 KILOMETERS

Location of

study area 

in Dane

County

Yahara R.

Black Earth Cr.

Yahara R.

Pheasant 

 Branch 

Lake Mendota

DANE COUNTY

05406500

05429650

05427718

05427948

EXPLANATION

City of Middleton

urban area

Other urban area 

within watershed

Agricultural land

Stream

Intermittent stream

Basin boundary

Road

Streamflow and water quality

monitoring site with station number

054279449

89°32'30"

89°30'

89°35'

43°07'30"

43°05' 

Figure 1. The Pheasant Branch watershed in Dane County, Wis.
4 Effects of Middleton Stormwater-Management Practices on Streamflow and Water Quality, Pheasant Branch

Data collected at the gaging station have been used for a 

number of City projects including:

• mapping of flood plains; 

• design of stormwater detention ponds ( Confluence 

Pond and South Pond); 

• design of South Pond, which includes the overflow 

features to Esser Pond; 

• identification of sites for infiltration ponds in the North 

Fork Pheasant Branch basin; determination of the 

recharge area of Frederick Springs for protection of the 

Pheasant Branch Marsh; and

• design of several channel erosion-control projects on 

Pheasant Branch. 

The data also were used during the development of the Storm 

Water Quality Plan (MSA Professional Services, 2007) for 

compliance with standards specified in State of Wisconsin 

rules NR216 and NR151(State of Wisconsin, Legislative Reference Bureau, 2009 a, b). Compliance with these standards 

is required for the city of Middleton to obtain a Wisconsin 

Pollution Discharge Elimination System Phase II permit to 

discharge stormwater runoff from the city’s stormwater sewer 

system. 

In addition, the streamflow-gaging station provides the 

streamflow and rainfall data required to develop and support 

the Middleton Storm Water Runoff Control Ordinance. In 

2007 and 2008, continuous specific conductance and chloride 

concentration data were collected at the gaging station to 

evaluate salt load carried by the stream and discharged into 

Lake Mendota from road deicing in the watershed.

Stormwater Runoff-Management 

Practices

Since 1979, the city of Middleton has used two main 

categories of practices for controlling flood discharges and 

improving the water quality of runoff; stormwater-management structures and nonstructural best management practices.

Stormwater-Management Structures

The stormwater-management structures constructed 

since 1975 include stormwater-detention ponds, water-quality 

retention ponds, and, more recently, infiltration basins, rain 

gardens, and bioretention basins. More than 100 stormwatermanagement structures were constructed in Middleton during 

1975–2008. Additional structures exist in Madison in the 

headwaters of the South Fork Pheasant Branch. Gabions, sheet 

piling, vane deflectors, and grade-control structures also have 

been installed to control channel erosion in the lower reaches 

of Pheasant Branch.

The two largest structures created for runoff control and 

water-quality retention in Middleton are locally referred to as 

the South Pond and the Confluence Pond. The South Pond is 

on the South Fork Pheasant Branch, and the Confluence Pond 

is on the main stem of Pheasant Branch at the confluence of 

the North and South Fork Pheasant Branches (fig. 1). The 

South Pond was constructed in 1992, and its main purpose is 

to reduce the flood peaks associated with nearby commercial 

and retail development. The South Pond outlet was redesigned 

in 2005 to allow higher discharges, greater than the 40-year 

flood, to overflow into Esser Pond to the east. The increased 

storage and diversion of discharges greater than the 100-year 

flood allowed for a narrowing of the flood plain downstream 

of Highway 14. In 2005, the South Pond was also deepened 

to provide more sediment trapping, and in 2008, it had a 

sediment trapping efficiency of about 30 percent (R.S. Grant 

Consulting Inc., oral commun., 2008). The Confluence Pond 

(fig. 2) was designed to reduce flood peaks and to improve 

water quality by trapping sediments. The pond was put into 

operation in November 2001 and has a trapping efficiency of 

about 35 percent (R.S. Grant Consulting Inc., oral commun., 

2008).

The South Pond and the Confluence Pond are the major 

runoff-control and water-quality retention structures on the 

main stems of Pheasant Branch in Middleton. The other 

structures in the watershed are considerably smaller and generally provide control of runoff from developments to meet the 

Middleton Storm Water Control Ordinance. An example of a 

smaller water-quality detention basin is the Northlake Pond 

(fig. 3). This and a similar basin were built in 1997 to fulfill a 

requirement that a 153-acre residential development include 

dedicated ponds and open space. Most of the runoff from 

the development flows into these detention basins, which are 

intended to trap a large part of the sediment and attached pollutants before water is released to Pheasant Branch Marsh. The 

load trapped by the pond was estimated by the Source Loading 

and Management Model (SLAMM) to be 12 tons per year .

A commercial infiltration basin in Middleton (fig. 4) collects and infiltrates the runoff from an auto dealership parking 

lot and building roofs. The combined parking and roof impervious area at this location is close to 100 percent of the entire 

auto dealership area. Developments like this and all other 

retail and commercial developments, are required to meet the 

runoff-, infiltration-, and sediment-control requirements of 

Middleton’s Storm Water Runoff Control Ordinance. 

A bioretention facility (fig. 5) was constructed in 2007 

to trap pollutants from a large retail parking lot. This facility 

was designed only to trap pollutants, because the soils in this 

area are not adequate for providing infiltration. To meet the 

infiltration requirement of Middleton’s Storm Water Runoff Ordinance, the developer was therefore required to pay 

a fee in lieu of the implementation of infiltration practices. 

These fees contribute to funding for the construction of larger 

stormwater-management facilities elsewhere in the watershed. 

The Confluence Pond and South Pond are examples of facilities that were partly funded by fees in lieu of implementation 
Stormwater Runoff-Management Practices 5

Figure 2. Confluence Pond on Pheasant Branch in Middleton, Wis., in 2008, with a view of the outlet 

structure. (Photo by W.A. Gebert)

Figure 3. Northlake Pond water-quality detention basin in Middleton, Wis., in 2008. (Photo by W.A. Gebert)
6 Effects of Middleton Stormwater-Management Practices on Streamflow and Water Quality, Pheasant Branch

Figure 4. Infiltration basin at retail dealership on Airport Road in Middleton, Wis., in 2008. (Photo by W.A. Gebert)

Figure 5. Bioretention facility at a commercial parking lot in Middleton, Wis., in 2008. (Photo by W.A. Gebert)
Stormwater Runoff-Management Practices 7

of various practices. The fees have also been used to fund the 

construction of facilities in areas that were developed prior to 

the enactment of the Storm Water Control Ordinance.

Nonstructural Best Management Practices 

Street sweeping and development of residential rain 

gardens are the main nonstructural best management practices in the Pheasant Branch watershed. Middleton adjusts its 

street sweeping frequency based on the amount of material on 

the streets. In 2008, the streets were swept once or twice per 

month. Records of street sweeping were not kept during the 

1970s, but streets probably were swept once or twice per year 

at that time. In addition, weekly sweeping of private parking lots or shopping centers constructed since about 1995 is 

required. 

In 2007, Middleton sponsored a program for developing 

residential rain gardens called “Plant Middleton” that solicited 

homeowners in Middleton who were interested in developing 

rain gardens to submit plans to the city for possible inclusion in the program. In 2007, 12 residences qualified for the 

program, and rain gardens were successfully constructed at all 

of the sites. Figure 6 shows one of the residential rain gardens. 

The program was started again in 2009, and 11 homeowners 

participated in it. The City program ended after 2009, because 

interest in it was low relative to the effort required for continuing it and because residents could also participate in a similar 

program sponsored by Dane County.

Figure 6. Photograph showing a residential rain garden in Middleton, Wis. (Photo by H. S. Garn)
8 Effects of Middleton Stormwater-Management Practices on Streamflow and Water Quality, Pheasant Branch

Changes in Streamflow Characteristics

Changes or trends in Pheasant Branch streamflow characteristics were determined by analyzing discharge data from the 

Pheasant Branch at Middleton streamflow-gaging station and 

precipitation data from the National Weather Service station at 

the Dane County Regional Airport (U.S. Department of Commerce, 2009). Streamflow data and methods of collection are 

described in USGS annual data reports, Water Resources Data, 

Wisconsin (U.S. Geological Survey, 1976–2006;U.S. Geological Survey 2007–9). The average annual streamflow for the 

period is 5.19 cubic feet per second (ft3/s). The annual average 

streamflow increased through the period 1975–2008 (fig. 7), 

and it approximately doubled from 1975 to 2008, as indicated 

by the least squares linear regression trend line shown in 

figure 7. This increase likely was caused by a combination of 

an increase in impervious area due to urbanization, an increase 

in annual precipitation (fig. 8) and expansion of the drainage 

area or stream network in 1999, when the city of Madison 

connected a 1.2-mi2 previously noncontributing area to the 

upstream part of the South Fork Pheasant Branch.

The average annual baseflow of 3.71 ft3/s for the period 

(fig. 7) was calculated by a baseflow separation technique 

(Gebert and others, 2007). Baseflow increased, as indicated by 

the least squares linear regression trend line shown in figure 

7; however, the annual baseflow did not increase as much as 

annual streamflow (fig. 7). Although increased impervious 

area usually causes decreased infiltration, aquifer recharge, 

and baseflow, the increased baseflow in Pheasant Branch, 

is notable because a decrease in baseflow could have been 

expected with the increase in impervious area.

The South Fork Pheasant Branch has not had a baseflow 

component before development or after development because 

the stream does not intersect the groundwater table. The North 

Fork Pheasant Branch does have a baseflow component for 

most of its length, and there is a small increase in baseflow 

in the main stem as it flows through the city. At the mouth, 

after Pheasant Branch flows through Pheasant Branch Marsh, 

annual baseflow increases substantially. (table 1). 

0

2

4

6

8

10

12

1975 1977 1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005 2007

Year

Total flow

Baseflow

Annual average streamflow and baseflow, in cubic feet per second

Least square trend line

Figure 7. Annual streamflow and baseflow at Pheasant Branch at Middleton, Wis. (station 05427948), 1975–2008.
Changes in Streamflow Characteristics 9

0

10

20

30

40

50

1975 1977 1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005 2007

Year

Annual precipitation, in inches

Least square trend line

Figure 8. Annual precipitation at Madison, Wis., 1975–2008. (Data from U.S Department of commerce 2009)

Table 1. Average annual baseflow at four sites in the Pheasant 

Branch watershed, Dane County, Wisconsin.

[USGS, U.S. Geological Survey; mi2, square miles; ft3/s, cubic feet per 

second]

USGS 

station 

number

Station name

Drainage 

area 

(mi2

)

Average 

annual 

baseflow 

(ft3

/s)

05427945 South Fork Pheasant 5.7 0

Branch at Highway 14

05427943 North Fork Pheasant 9.6 2.83

Branch at Airport Road

05427948 Pheasant Branch at 18.3 3.71

Middleton

05427952 Pheasant Branch at mouth 24.5 5.80

The annual streamflow from 1993 to 2008 showed an 

abrupt increase of 62 percent from the 1975–92 period (fig. 9). 

Some gradual increase in streamflow might be expected 

because of the continued increase in development in the 

watershed, and some of the increased annual streamflow might 

be attributed to increased precipitation after 1992, which was 

7 percent greater than during the 1975–92 period. However, 

the relation of cumulative streamflow as a function of cumulative precipitation (fig. 10) indicates that unit runoff per unit of 

precipitation was 43 percent greater for the period after 1992. 

This abrupt increase in streamflow may have been due to the 

increase in precipitation and the rapidly increasing development in the South Fork Pheasant Branch, including the 1999 

connection of an area in the watershed that had previously 

been internally drained. Straight line segments, rather than 

a more gradual curve, representing the data for the pre- and 

post-1993 time periods (fig. 9) illustrate the abrupt increase. 

Annual flood-peak discharges at Pheasant Branch at 

Middleton have increased during the 1975–2008 period 

(fig. 11). Although a least squares linear regression trend 

analysis shows, the apparent trend was not statistically significant; the flood-peak discharge values for various recurrence 

intervals have changed considerably during the past 34 years. 

Flood-peak discharge values for all recurrence intervals from 

the 2- to the 100-year floods increased 37–83 percent from the 

1975–1991 period compared with those from the 1992–2008 

period (table 2). The flood-peak discharge values shown in 

table 2 were calculated from Log Pearson Type III analyses.

The increase in flood peak discharges could be caused by 

urbanization, an increase in recent precipitation, or the addition of the formerly internally drained area to the South Fork 

Pheasant channel.

An evaluation of the effects of urbanization on Pheasant Branch (Krug and Goddard, 1986) included a model that 

estimated the changes in flood peak discharges that could 

occur with several urbanization scenarios. The scenarios used 

for simulation were 1985 conditions, partial urbanization 

expected over the next 20 years (1985–2005), and complete 

urbanization of the basin. The partial urbanization scenario 
10 Effects of Middleton Stormwater-Management Practices on Streamflow and Water Quality, Pheasant Branch

0

10,000

20,000

30,000

40,000

50,000

60,000

70,000

1975 1980 1985 1990 1995 2000 2005 2010

Year

1975–1992

1993–2008

Cumulative annual streamflow, in cubic feet per second-days

Figure 9. Cumulative annual streamflow at Pheasant Branch at Middleton, Wis. (station 05427948), 

1975–2008. 

y = 64.62x - 10338.36

R2 = .999

y = 44.64x + 1189.91

R2 = .998

0

10,000

20,000

30,000

40,000

50,000

60,000

70,000

0 200 400 600 800 1,000 1,200

Cumulative precipitation, in inches

1975–1992

1993–2008

Cumulative streamflow, In cubic feet per second-days

Figure 10. Comparison of annual streamflow of Pheasant Branch at Middleton, Wis. (station 

05427948) and annual precipitation at Madison, Wis., 1975–2008.
Changes in Streamflow Characteristics 11

0

200

400

600

800

1,000

1,200

19751977197919811983198519871989199119931995199719992001200320052007

Year

Annual flood peak discharge, in cubic feet per second

Least square trend line

Figure 11. Annual flood-peak discharges at Pheasant Branch at Middleton, Wis. (station 05427948), 

1975–2008.

Table 2. Flood-peak discharges for various recurrence intervals at Pheasant Branch at Middleton, Wis. (station 

05427948), 1975–2008.

[ft3/s, cubic feet per second]

Recurrence interval 

(years)

Period of record Increase 1975–91 to 

1992–2008 (percent) 1975–91 (ft3

/s) 1992–2008 (ft3/s) 1975–2008 (ft3/s)

2 276 378 320 37

5 485 736 592 52

10 635 1016 795 60

25 833 1410 1,070 69

50 985 1,740 1,290 76

100 1,140 2,090 1,510 83
12 Effects of Middleton Stormwater-Management Practices on Streamflow and Water Quality, Pheasant Branch

best represents current (1975–2008) development in the watershed. A comparison of flood peaks based on 1975–2008 data 

to the flood peaks simulated for projected partial urbanization 

(table 3) shows that the 2-year recurrence interval flood peak 

for current conditions is not as large as that simulated for projected partial urbanization. For recurrence intervals of 5 years 

and greater, the opposite is true: flood peaks for 1975–2008 

conditions are much higher than were simulated for expected 

partial urbanization. 

The results of the model were very useful for Middleton 

to be aware of the increases in flood peak discharges that could 

occur with urbanization and the implementation of numerous storm water management practices. While the model was 

successfully calibrated using flow data from 1975–1980 , the 

model has limitations due to the complexity of handling the 

various water control structures. Therefore the projected flood 

discharges may have larger errors than those computed from 

recorded data and may not provide a very accurate tool for 

evaluating the effectiveness of stormwater management structures or the impact of urbanization. 

To evaluate likely causes for the increase in flood-peak 

discharges at Pheasant Branch, peak discharge data from 

the same periods at three nearby streamflow-gaging stations 

were compared to data from Pheasant Branch at Middleton 

(05427948). One station, Spring Harbor Storm Sewer at Madison (05429650), is a completely urbanized basin, and the other 

two, Black Earth Creek near Black Earth (05406500) and 

Yahara River at Windsor (05427718), are largely agricultural 

basins that have small urban areas. A plot of annual flood-peak 

discharges shows that the same trend of increasing flood peaks 

observed in Pheasant Branch also occurred in these watersheds (fig. 12) probably as the result of increased precipitation. 

Although the flood peaks increased at all four sites, a comparison of the slope of the trend lines shows the increase was 

much larger for Black Earth Creek and Yahara River, where 

the primary land use is agricultural, than for Pheasant Branch, 

where the land use is a mixture of agricultural and urban, and 

Spring Harbor, where the land use is mostly urban.

Table 3. Comparison of flood peak discharges based on simulated annual peak discharges and actual annual 

flood peak discharges.

[ft3/s, cubic feet per second; –, decrease; +, increase; simulated peak discharge from Krug and Goddard, 1986]

Recurrence interval

(years)

Flood peak discharges 

based on simulated peak 

discharge for 

partial urbanization (ft3

/s)

Flood peak discharges 

based on actual annual 

peak discharge 1975–2008 

(ft3

/s) 

Difference between 

simulated and actual 

peak discharge

(percent)

2 350 320 –9

5 483 592 +23

10 567 795 +40

25 670 1,070 +60

50 744 1,290 +73

100 815 1,510 +85
Pheasant Branch at Middleton (05427948)

0

200400600800

1,0001,200

1975

1977

1979

1981

1983

1985

1987

1989

1991

1993

1995

1997

1999

2001

2003

2005

2007

Year

Flood peak discharge,

In cubic feet per second Least square trend line

Black Earth Creek (05406500)

0

200400600800

1,0001,2001,4001,6001,800

1975

1977

1979

1981

1983

1985

1987

1989

1991

1993

1995

1997

Year

Flood peak discharge, 

In cubic feet per second

Yahara River (05427718)

0

500

1,0001,5002,0002,5003,0003,500

1976

1978

1980

1982

1984

1986

1988

1990

1992

1994

1996

1998

2000

2002

2004

2006

2008

Year

Flood peak discharge,

In cubic feet per second

Spring Harbor (05427965)

0

100200300400500600700800

1976

1978

1980

1982

1984

1986

1988

1990

1992

1994

1996

1998

Year

Flood peak discharge,

In cubic feet per second

Figure 12. Comparison of annual flood peaks of Pheasant Branch at Middleton with annual flood peaks at three nearby streams at three gaging for 1976–2008.
14 Effects of Middleton Stormwater-Management Practices on Streamflow and Water Quality, Pheasant Branch

A more detailed comparison of the difference in flood 

peaks for the urban and rural watersheds is shown in table 4 

for the three stations that had comparative periods of record. 

Changes in flood peak discharges for various recurrence intervals were compared for the three basins by calculating flood 

frequency values for the period 1975–91 to the values for the 

period 1992–2008. As mentioned previously, the flood peak 

discharges for Pheasant Branch increased by 37 percent for 

the 2-year recurrence interval and by 83 percent for the 100-

year recurrence interval. The 2-year flood-peak discharges for 

Spring Harbor Storm Sewer increased by 11 percent but they 

decreased for the 10-year and greater recurrence intervals by 

7-13 percent. For Black Earth Creek, the increase was 43 percent for the 2-year recurrence interval and up to 140 percent 

for the 100-year recurrence interval. Based on the changes in 

these two basins, the increase in peak discharges in Pheasant Branch was probably due to a combination of factors—

increased precipitation and increased urbanization, mitigated 

by stormwater-management practices that help to reduce the 

increases. Although it is possible that the enlarged drainage 

area in the South Fork Pheasant Branch in 1999 contributed to 

the increase in flood peaks in the Pheasant Branch watershed, 

the enlarged drainage area is probably not significant, because 

the city of Madison constructed several large detention basins 

to control the flood peaks. In addition, the South Pond was 

constructed in 1992 to reduce flood peaks. These detention 

ponds may have mitigated the effects that increased drainage 

area and increasing urbanization had on increasing the flood 

peaks.

A comparison of flood peaks per square mile of basin 

(fig. 13) illustrates that flood peaks are generally much higher 

in urbanized areas. For Spring Harbor Storm Sewer, a completely urbanized basin, the annual flood peaks for the period 

average 129 ft3

/s compared to 23 ft3/s for Pheasant Branch, a 

watershed that is approximately 50 percent urbanized at the 

Pheasant Branch at Middleton gaging station. The average 

annual flood peaks for the two rural watersheds are 29 ft3/s 

for Black Earth Creek and 17 ft3/s for Yahara River. Based 

on these comparisons it appears that Pheasant Branch flood 

peak discharges are similar to those of rural watersheds and 

the runoff control practices in the Pheasant Branch watershed 

have been effective in suppressing the increases in flood peaks 

that occur with urbanization.

Based on these analyses of flood peaks the conclusions 

are:

1. Flood peak discharges have been increasing since 1975. 

2. The primary reason for the increase appears to be 

increased precipitation and increase urbanization. 

3. The stormwater management techniques used by Middleton have been effective in minimizing the increase in 

flood peak that usually occurs with urbanization 

Changes in Water-Quality 

Characteristics

Changes or trends in Pheasant Branch water-quality characteristics were determined by analyzing suspended-sediment 

and total phosphorus discharge and concentration data from 

the Pheasant Branch at Middleton station. In addition, specific 

conductance was monitored and chloride concentrations and 

loads were determined for two winter seasons to evaluate the 

effects of the application of road deicing salt on stream water 

quality.

Table 4. Comparison of changes in flood peak discharge values at three U.S. Geological Survey 

streamflow-gaging stations near Middleton, Wis.

[+, increase; –, decrease]

Change 1975–91 to 1992–2008

(percent)

Recurrence 

interval

(years)

Pheasant Branch at 

Middleton, Wis.

(station 05427948)

Black Earth Creek near 

Black Earth, Wis.

(station 05406500)

Spring Harbor

Storm Sewer at Madison, 

Wis. (station 05429650)

2 +37 +43 +11

5 +52 +72 +1

10 +60 +89 –13

25 +69 +110 –7

50 +76 +130 –9

100 +83 +140 –10
Changes in Water-Quality Characteristics 15

Suspended Sediment and Total Phosphorus

Suspended-sediment discharge has been determined 

for Pheasant Branch at Middleton (station 05427948) since 

December 1977. An automatic pump sampler was used to 

obtain sediment-concentration data during runoff events, and 

the concentration data were then used with the streamflow 

data to compute daily sediment loads according to techniques 

described by Porterfield (1972). The annual suspended-sediment load from 1978 to 2008 decreased, as indicated by the 

least squares trend line in figure 14. 

0

50

100

150

200

250

197619771978197919801981198219831984198519861987198819891990199119921993199419951996199719981999200020012002200320042005200620072008

Year

Spring Harbor

Discharge, in cubic feet per second per square mile

Least square trend line

Pheasant Branch

Black Earth Creek

Yahara River

Figure 13. Comparison of annual flood peak discharges in cubic feet per second per square mile at four gaging stations in Wisconsin 

for 1976–2008: Pheasant Branch at Middleton (station 05427948), Black Earth Creek at Black Earth (station 05406500), Yahara River at 

Windsor (station 05427718), and Spring Harbor Storm Sewer at Madison (station 05429650). 

0

1,000

2,000

3,000

4,000

5,000

6,000

7,000

1978

198019821984198619881990199219941996199820002002200420062008

Year

Suspended-sediment load, in tons

Least square trend line 

Figure 14. Annual suspended-sediment loads for Pheasant Branch at Middleton, Wis. (station 05427948), 1978–2008.
16 Effects of Middleton Stormwater-Management Practices on Streamflow and Water Quality, Pheasant Branch

Annual average suspended-sediment concentrations were 

determined by dividing the annual suspended-sediment load 

by the annual flow volume. Suspended-sediment concentrations generally increase with increasing flows, and despite the 

increasing annual flow volumes in Pheasant Branch, suspended-sediment concentrations show an obvious decreasing 

trend (fig. 15). This unusual divergence may be a direct result 

of the adoption of Middleton’s Storm Water Runoff Control 

Ordinance in 1975 and the subsequent construction of more 

than 100 stormwater-management facilities or structures.

Especially significant is the reduction in average annual 

suspended-sediment load since the construction of the Confluence Pond in 2001. The average annual sediment load for 

the 1978–2008 period was 2,110 ton/yr. Prior to construction 

of the Confluence Pond (1975–2001), the average annual 

suspended-sediment load was 2,650 ton/yr, but after 2002, the 

average annual suspended-sediment load was reduced to 1,450 

ton/yr, for the period 2002–8 for a decrease of 45 percent.

Although overall suspended-sediment loads have 

decreased in Pheasant Branch, some years that had anomalously high loads were the result of intense rainfall or construction activities in the watershed. In 2004, during the 

construction of a bypass for U.S. Highway 12, several large 

storms struck when much of the construction area had bare 

soil, steep slopes, and few or no erosion-protection measures. 

The large sediment load in 2004 (fig. 14) was the result of 

those storms, and the relatively large load in 2008 was the 

result of many storms that produced the largest annual flow 

volume for the period of record. The annual suspended-sediment concentrations have been much lower than expected for 

the annual flow volumes since 2002, except for the unusual 

storm years of 2004 and 2008 (fig. 15).

Total phosphorus discharge has been determined at the 

Pheasant Branch at Middleton gaging station since 1993. The 

average annual phosphorus load for the period 1993, 1995–

2008 was 9,450 pounds per year (lb/yr); fig. 16.The annual 

phosphorus load decreased, as shown by the least squares 

trend line (fig. 16), similar to the annual sediment load. This 

decrease was expected, because part of the total phosphorus load is attached to the sediment. Although the record for 

phosphorus starts in the middle of the urbanization period, the 

annual phosphorus load still shows a decrease, mainly because 

the Confluence Pond traps sediments that would have entered 

Pheasant Branch prior to the pond’s construction in 2001. 

0

500

1,000

1,500

2,000

2,500

3,000

3,500

4,000

4,500

1975 1980 1985 1990 1995 2000 2005 2010

Year

Flow volume

Flow volume, in cubic feet per second-days

Suspended-sediment concentration

concentration, in milligrams per liter

Least square trend line

Figure 15. Annual flow volumes and annual average suspended-sediment concentrations for 

Pheasant Branch at Middleton, Wis. (station 05427948), 1978–2008.
Changes in Water-Quality Characteristics 17

During the period 1993, 1995–2001, prior to the construction of the Confluence Pond, the annual phosphorus load was 

12,200 lb/yr; after 2002, the annual load decreased by 48 percent to 6,300 lb/yr. As was the case for suspended sediment, 

the shorter 1993–2008 record for phosphorus shows similar 

decreasing annual phosphorus concentrations, although flow 

volumes increased during the same period (fig. 17). 

The other part of the total phosphorus load is dissolved 

ortho phosphorus, which is not attached to the sediment load 

and, therefore, may not show the same decreasing trend. 

0

5,000

10,000

15,000

20,000

25,000

30,000

1993199419951996199719981999200020012002200320042005200620072008

Year

Phosphorus load, in pounds

Least square trend line

Figure 16. Annual phosphorus loads for Pheasant Branch at Middleton, Wis. (station 05427948), 1993, 

1995–2008.

0

500

1,000

1,500

2,000

2,500

3,000

3,500

4,000

4,500

1990 1995 2000 2005 2010

Year

Streamflow volume

Total phosphorus concentration

Flow volume, in cubic feet per second - days

concentration, in micrograms per liter

Least square trend line

Figure 17. Annual flow volumes and annual average total phosphorus concentrations for Pheasant 

Branch at Middleton, Wis. (station 05427948), 1993, 1995–2008.
18 Effects of Middleton Stormwater-Management Practices on Streamflow and Water Quality, Pheasant Branch

A good example of that divergence from the trend was in 

2005 (fig. 18), when the annual phosphorus load was much 

larger relative to the annual sediment load. During February 

and March 2005, three rainfall events occurred over frozen 

ground, resulting in relatively modest increases in streamflow 

and sediment loads but very large total phosphorus loads. The 

total phosphorus load for those 2 months was 7,100 lb, or 87 

percent of the annual load of 8,250 lb for the entire year. Normally the Confluence Pond would have reduced the total phosphorus and suspended sediment loads, but in 2005, most of the 

phosphorus load for February and March was dissolved ortho 

phosphorus that passed through the Confluence Pond because 

it was not attached to sediment. Agricultural runoff is usually 

the source of dissolved phosphorus, and in 2005 the rainfall 

events occurred when the ground was frozen, allowing a large 

amount of dissolved phosphorus to enter the stream system. 

To evaluate the possible causes for the changes in annual 

sediment and phosphorus loads seen in Pheasant Branch, data 

from two other streams that discharge into Lake Mendota were 

compared to data from Pheasant Branch (table 5). The streams 

are Spring Harbor Storm Sewer at Madison, a completely 

urbanized basin, and Yahara River at Windsor, a basin where 

the predominant land use is agricultural.

For the period 1993–2001, Pheasant Branch had the 

highest contributing load and yields to Lake Mendota for the 

three major streams discharging to the lake, but annual loads 

changed significantly after construction of the Confluence 

Pond in 2001. Since that time, the annual sediment load for 

Pheasant Branch has decreased 45 percent and the annual 

phosphorus load has decreased 48 percent. In contrast, for the 

same period, the annual sediment load at the urban Spring 

Harbor Storm Sewer station decreased by 10 percent, while 

the annual sediment load at the agricultural Yahara River 

station decreased by 18 percent and the annual phosphorus 

load decreased by 3 percent. This difference in the change in 

loads for Pheasant Branch, compared with the other streams, 

indicates that the Confluence Pond and other stormwater-management facilities constructed since 2001 have significantly 

reduced the loads from Pheasant Branch. After 2001, Pheasant 

Branch total phosphorus yields are less than those from Yahara 

River at Windsor. Both Pheasant Branch and Spring Harbor 

Storm Sewer, the urban streams, have higher suspended-sediment yields than Yahara River (table 5).

In addition to the long-term monitoring of suspended 

sediment at the Pheasant Branch at Middleton, sediment 

was also monitored continuously at four other stations in the 

Pheasant Branch watershed during the period 1978–81. The 

four other stations were: 

1. South Fork Pheasant Branch at Highway 14 (05427945), 

2. North Fork Pheasant Branch at Airport Road (05427943), 

3. Pheasant Branch at Century Avenue (05427950), and

4. Pheasant Branch at Mouth (05427952). 

A comparison of the annual suspended-sediment loads 

from the five sites in the Pheasant Branch watershed indicates 

the variability and sources of sediment load in the watershed 

(table 6). The South Fork and North Fork contributed similar 

loads of suspended sediment, except during the wet year of 

0

2,000

4,000

6,000

8,000

10,000

12,000

1993199419951996199719981999200020012002200320042005200620072008

Years

0

5,000

10,000

15,000

20,000

25,000

30,000

Flow volume, in cubic feet per second - days

suspended-sediment load, in tons

Phosphorus load, in pounds

Annual flow volume

Suspended-sediment load

Total phosphorus load

Figure 18. Annual flow volumes, suspended-sediment loads, and total phosphorus loads for Pheasant Branch at Middleton, 

Wis. (station 05427948), 1993–2008.
Changes in Water-Quality Characteristics 19

Table 5. Comparison of annual sediment and phosphorus loads for three major streams contributing to Lake Mendota, Wis., for the 

periods 1993, 1995–2001, and 2002–8.

[USGS, U.S. Geological Survey; mi2, square mile; ton/mi2; tons per square mile; lb, pound; lb/mi2; pound per square mile:—, data not available]

USGS station 

number Stream name

Contributing 

drainage

 area (mi2

)

Time 

period

Annual 

suspended 

sediment

 load (tons)

Annual 

suspended 

sediment 

yield (tons/mi2

)

Annual total 

phosphorus 

load (lb)

Annual total 

phosphorus 

yield (lb/mi2

)

05427948 Pheasant Branch at 

Middleton 

17.1 1993–2001

2002–2008

2,650

1,450 

155

84.7

12,200

6,300 

713

368

05429650 Spring Harbor 

Storm Sewer

3.29 1993–2001

2002–2008

321

287

97.6

87.2

—

—

—

—

05427718 Yahara River at 

Windsor

37.0 1993–2001

2002–2008

2,460

2,010

66.3

54.3

15,700

15,300

424

413 

Table 6. Comparison of annual suspended sediment load for five U.S. Geological Survey streamflow-gaging stations on Pheasant 

Branch near Middleton, Wis., 1978–81.

[All load data are in tons. USGS, U.S. Geological Survey; mi2, square mile; —, data not available]

Year

South Fork Pheasant 

Branch at Highway 14

(station 05427945, 

drainage area 5.74 mi2

)

North Fork Pheasant Branch 

at Airport Road

(station 05427943, 

drainage area 9.61 mi2

)

Pheasant Branch at 

Middleton

(station 05427948, 

drainage area 18.3 mi2

)

Pheasant Branch at 

Century Avenue

(station 05427950, 

drainage area 20.8 mi2

)

Pheasant Branch at 

mouth

(station 05427952, 

drainage area 24.5 mi2

)

1978 3,478 734 6,424 6,351 5,877

1979 358 569 606 518 723

1980 555 661 1,099 1,077 1,215

1981 — — 1,774 2,237 1,059

Total — — 9,903 10,183 8,874

1978, when the South Fork contributed almost five times as 

much suspended sediment as the North Fork. Downstream 

from Pheasant Branch at Middleton, the lower reach sometimes is a sediment source as shown in the increase in load for 

1981 for the station at Century Avenue. The reach between 

these two gages has a very steep gradient and active bank erosion, and it was thought to be a large contributor of sediment, 

but which was apparent only in 1981. Pheasant Branch Marsh, 

as reflected by the data from the station at the mouth, can be a 

sediment trap in some years (1978, 1981) and a source in other 

years (1979, 1980). The trapping of sediment in Pheasant 

Branch Marsh, which includes the area between the Century 

Avenue station and the station at the mouth, averaged 13 percent of the sediment load for the monitoring period. 

Spatial Variability of Suspended Sediment in 

Pheasant Branch in 2008

 To evaluate spatial changes in sediment characteristics 

of South Fork Pheasant Branch, North Fork Pheasant Branch, 

and Pheasant Branch downstream from the Confluence Pond 

to the mouth at Lake Mendota, suspended sediment was 

sampled in 2008 at multiple sites and particle size distribution 

was analyzed. Representative samples were obtained by use of 

a depth-integrating suspended-sediment sampler and “equalwidth-increment” (EWI) methods (Edwards and Glysson, 

1999). These procedures generate a representative crosssectional sample that is both flow-weighted and depth- and 

width-integrated. Discharge was measured to determine flow 

at the time of the sample. Samples were collected at five sites 

on Pheasant Branch: 
20 Effects of Middleton Stormwater-Management Practices on Streamflow and Water Quality, Pheasant Branch

1. North Fork Pheasant Branch immediately upstream from 

the Confluence Pond (culvert at foot trail crossing, station 

054279435); 

2. South Fork Pheasant Branch upstream from the Confluence Pond at Deming Way bridge (station 054279465); 

3. Pheasant Branch at Middleton (station 05427948; high 

flows were collected at the trail foot bridge adjacent to 

new Highway 12 downstream of the Confluence Pond);

4. Pheasant Branch at trail footbridge downstream from 

Century Avenue and upstream from marsh (station 

054279501); 

5. Pheasant Branch at Mouth (trail footbridge near the 

mouth with Lake Mendota, upstream from Century 

Avenue, station 05427952).

Synoptic samples were collected at the above five sites, 

from upstream to downstream, over three different flow ranges 

(measured at the gaging station) to represent:

• lower flows (about 10–20 ft3/s ), 

• medium flows (about 20–50 ft3/s) and 

• higher flows (greater than 100 ft3/s). 

Samplings were repeated for three different events during the 

season. This sampling schedule yielded nine samples at each 

site. 

Water samples from all five sites were analyzed for 

suspended-sediment concentration and particle-size distribution, as a percentage finer than 0.0625 millimeters (mm; sand/

fines particle-size break). Additional particle-size distribution 

analysis for percentage finer than 0.004 mm (clay/silt break) 

was done for samples from the downstream three sites (3–5 

above) if sufficient sediment was present.

Although suspended-sediment data collected in 2008 at 

the five sites along Pheasant Branch are too few to calculate 

loads, the data indicate that concentrations and particle sizes 

have changed from earlier data. The greatest concentrations of 

suspended sediment were during high discharges, and concentrations from South Fork Pheasant Branch were greater than 

those from North Fork Pheasant Branch the majority of times. 

Concentrations at the Pheasant Branch at Middleton gaging 

station were lower than those of both forks, reflecting the 

removal of sediment by the Confluence Pond upstream from 

the gaging station. Suspended-sediment particle-size distribution at the Pheasant Branch at Middleton gaging station and at 

North and South Fork Pheasant Branch tributaries upstream 

from the Confluence Pond (table 7) was predominantly (generally 86–99 percent) less than sand size (0.0625 mm), similar 

to data collected previously during 1978–81 (U.S. Geological 

Survey, 1979–81). At site 4, downstream of Century Avenue 

and upstream from the marsh, however, suspended sediment 

finer than sand ranged from 10 to 99 percent. The sample 

collected at site 4 on April 11, 2008, after peak flow at a discharge of 324 ft3

/s and concentration of 3,040 milligrams per 

liter (mg/L), is noteworthy, because only 10 percent was finer 

than sand (90 percent was sand). Peak discharge for that event 

occurred at 2:00 a.m. and was about 620 ft3/s. Results for 

some events are difficult to interpret, because time of sampling 

varied with travel time of water. Previous samples collected at 

site 4, downstream of Century Avenue and upstream from the 

marsh, during 1979–81 had sediment finer than sand ranging 

from 56 to 100 percent, over a range of discharges from 34 to 

286 ft3/s and concentrations from 435 to 1,450 mg/L. The lowest percentage, 56 percent, was on Sept.1, 1981, at a discharge 

of 286 ft3/s and a concentration of 868 mg/L. 

Almost all sources of sand in the lower reach downstream of the Pheasant Branch at Middleton station are from 

the sloughing of sand bluffs and erosion of channel banks in 

the reach. The author made the following observations from 

inspections of the reach from the gaging station to the marsh 

over the past 15 years:

1. erosion and sloughing of high sand bluffs adjacent to and 

undercut by the creek has accelerated with the increased 

frequency and magnitude of flood events since 1993, and 

2. deposition of sand in the channel reach upstream of the 

marsh has filled and widened the channel and created a 

delta deposit with a braided channel where it enters the 

marsh (fig. 19).

Specific Conductance and Chloride Monitoring, 

2007–8

“Road salt,” usually sodium chloride, commonly used 

to deice roads in winter, is highly soluble, and moves easily through soils into water bodies or streams. A recent study 

of the effects of road deicing salt on water quality (Corsi 

and others, 2010) found that when the snow melts in urban 

areas where large amounts of salt are used on roads, chloride 

concentrations can rapidly rise to levels that may be toxic to 

aquatic life (Corsi and others, 2010). The authors of the study 

found that maximum chloride concentrations in many Milwaukee streams exceeded several thousand milligrams per liter. 

Samples from 7 of 13 Milwaukee area streams during two 

road salt runoff events exhibited toxicity to aquatic life and 

had chloride concentrations up to about 7,000 mg/L. The U.S. 

Environmental Protection Agency (EPA, U.S. Environmental 

Protection Agency, 1988) water-quality criteria for chloride are 

230 milligrams per liter (mg/L) for chronic long-term exposure of aquatic animals (4-day average) and 860 mg/L for the 

acute short term. Corsi and others (2010) evaluated chlorideconcentration estimates in 11 watersheds where urban land use 

ranged from 6 to 100 percent. Specific conductance was elevated during cold-weather months at all sites, and it remained 

somewhat elevated during warm-weather months at the urban 

land-use sites where the largest amounts of road deicing salt 

were applied. Estimated chloride concentrations exceeded 

the EPA acute (860 mg/L) and chronic (230 mg/L) waterquality criteria at 55 and 100 percent of the sites, respectively. 
Table 7. Summary of suspended-sediment data collected at five U.S. Geological Survey stations on Pheasant Branch in Middleton, Wis., during 2008[Date is shown by year, month, and day. ft3/s, cubic feet per second; <, less than; mm, millimeters; mg/L, milligrams per liter; streamflow conditions are represented by the colors 

Lower streamflow

Medium streamflow

Higher streamflow

Station 54279435

North Fork Pheasant Branch west of Confluence Pond

Station 54279465

 South Fork Pheasant Branch at Deming Way

Station 

Pheasant Branc

Date Time Discharge (ft3/s)

Percentage of

suspendedsediment 

particle size

<0.0625 mm

Suspendedsediment 

concentration

(mg/L)

Date Time Discharge (ft3/s)

Percentage of 

suspendedsediment 

particle size

<0.0625 mm

Suspendedsediment 

concentration 

(mg/L)

Date Time Discharge (ft3/s)

20080313 0850 5.2 70 22 20080313 0925 1.8 93 42 20080313 1000 11 20080314 1715 30 86 19 20080314 1800 8.3 98 57 20080314 1825 41 20080401 1230 10 95 10 20080401 1305 6.3 98 44 20080401 1335 27 20080409 0715 19 98 86 20080409 0755 16 96 83 20080409 0825 51 

20080411 0645 110 99 301 20080411 0615 99 98 240 20080411 0750 262 20080425 0745 120 100 754 20080425 0705 134 98 205 20080425 0845 272 20080708 0640 15 97 39 20080708 0710 25 91 116 20080708 0735 46 20080711 0630 89 99 110 20080711 0705 249 89 226 20080711 0745 403 20080804 0835 8.3 92 4 20080804 0900 1.3 98 24 20080804 0930 20 

Station 54279501 

Pheasant Branch upstream from marsh

Station 5427952

Pheasant Branch at mouth

Date Time Discharge (ft3/s)

Percentage of 

suspendedsediment 

particle size

<0.0625 mm

Suspendedsediment 

concentration 

(mg/L)

Date Time Discharge (ft3/s)

Percentage of 

suspendedsediment 

particle size

<0.0625 mm

Suspendedsediment 

concentration 

(mg/L)

20080313 1035 11 99 50 20080313 1130 17 94 41

20080314 1850 45 95 59 20080314 1925 77 75 3820080401 1410 27 96 32 20080401 1505 44 98 1520080409 0855 58 91 111 20080409 0930 69 97 4920080411 0925 324 10 3040 20080411 1050 364 88 15820080425 0935 336 67 346 20080425 1045 276 94 11020080708 0800 46 70 125 20080708 0830 72 79 4120080711 0910 393 78 373 20080711 0955 284 48 18520080804 0950 20 86 55 20080804 1020 28 79 10
22 Effects of Middleton Stormwater-Management Practices on Streamflow and Water Quality, Pheasant Branch

Figure 19. Pheasant Branch upstream from marsh showing sand deposition, channel widening, and overflow channels 

entering marsh. (Photo by H.S. Garn)

Generally, elevated chloride concentrations exceeding chronic 

effect levels were widespread in urban areas of the Midwest 

and Northeast (Mullaney and others, 2009).

To evaluate the effect of road deicing salt on stream water 

quality in the Pheasant Branch watershed, specific conductance and chloride were monitored during two winter seasons. 

Continuous specific conductance monitoring and stream water 

sampling to determine chloride concentrations were conducted from February 2007 through April 2008 at the Pheasant 

Branch at Middleton gaging station. In 2007, 16 water samples 

were collected for chloride analysis and 10 were collected 

in 2008. These data were then used to develop a regression 

model to estimate continuous concentrations of chloride and 

compute daily chloride loads (Rasmussen and others, 2008) of 

Pheasant Branch for the monitoring period. Analytical results 

from concurrent analysis of chloride and specific conductance 

were used to determine the relation between specific conductance and chloride concentration. Regression of sampling data 

resulted in an R2

 = 0.927 to estimate chloride concentrations 

(fig. 20). Time-weighted adjustments were also applied to 

the estimated concentrations during some periods to better-fit 

measured concentrations from measurement to measurement. 

The measured and estimated chloride concentrations of 

Pheasant Branch during the two winter seasons are shown in 

figure 21. The maximum estimated concentration of chloride 

during the monitoring period was 931 mg/L on March 1, 

2007, and it exceeded the EPA acute criterion of 860 mg/L. 

Chloride concentrations exceeded the EPA chronic criterion 

of 230 mg/L for at least 10 days during February and March 

2007 and for 45 days from December to the first week in April 

during the 2007–8 winter season. The maximum concentration 

in 2008 reached 680 mg/L twice during February. These high 

concentrations of chloride occurred in spite of the attenuating 

effect of the Confluence Pond about 0.3 miles upstream from 

the gaging station. Following the winter peaks, concentrations 

of chloride remained elevated above background concentration 

through April, long after all snow had melted. Chloride concentrations during the summer generally were about 50–100 

mg/L, which may still be elevated above natural background 

concentrations. The average chloride concentration for the 
Changes in Water-Quality Characteristics 23

y = 0.00005944x2 + 0.06757933x

R2

 = 0.927

0

100

200

300

400

500

600

700

0 500 1,000 1,500 2,000 2,500 3,000

Specific conductance, in microsiemens per centimeter

Chloride concentration, In milligrams per liter

Figure 20. Regression relation of specific conductance and chloride concentration at Pheasant Branch at 

Middleton, Wis. (station 05427948).

A.

B.

0

100

200

300

400

500

600

700

800

900

1000

2/1/07 3/3/07 4/2/07 5/2/07 6/2/07 7/2/07 8/1/07 8/31/07 10/1/07

Date

Concentration, in milligrams per liter

EPA chronic criterion

0

100

200

300

400

500

600

700

800

10/1/07 10/31/07 11/30/07 12/31/07 1/30/08 3/1/08 3/31/08 4/30/08

Date

EPA chronic criterion

Concentration, In milligrams per liter

Estimated chloride based on relation with specific 

conductance

Chloride determined by sample analysis

Figure 21. Measured and estimated chloride concentrations of Pheasant Branch at Middleton, Wis. (station 05427948) during 

February through September 2007 (A) and October 2007 through April 2008 (B). (EPA, U.S. Environmental Protection Agency)
24 Effects of Middleton Stormwater-Management Practices on Streamflow and Water Quality, Pheasant Branch

entire monitoring period was 137 mg/L and the median was 

118 mg/L. Chloride concentrations during 1977 generally 

ranged from about 15–25 mg/L (U.S. Geological Survey, 

1978), which may be more representative of natural background concentrations. 

Peak concentrations of chloride during the winter usually 

occurred during times of low flow, when air temperatures 

warmed enough to melt snow and ice on the roads, or when 

a light rain was sufficient to wash salt into the storm sewers; 

however, overall melting or rainfall did not increase runoff 

enough to dilute the salt. An example of this situation occurred 

during February 17–24, 2008 (fig. 21). Thirteen inches of 

snow fell on February 17, initiating road salt application. Runoff associated with a light rain at the beginning of the storm 

caused a peak specific conductance of 2,860 microsiemens 

per centimeter (μS/cm; 680 mg/L chloride). Warm afternoons 

on following days (February 22–24) melted snow on roadways and caused corresponding peaks in specific conductance 

greater than 2,000 μS/cm (370 mg/L chloride). During this 

time, streamflow was at baseflow, about 2.5 ft3/s, and it never 

exceeded 6 ft3/s. Diurnal peaks in chloride concentration 

can occur over several days during a winter when conditions 

include the right combination of snow on roads and midday 

temperatures above freezing. The small runoff events produce 

the highest concentration of chloride in the stream; in contrast, during large runoff events caused by extended periods of 

melting snow or heavy rains, the salt content in the stream is 

diluted and decreases with increasing flow. 

Daily chloride loads were computed from the estimated continuous concentration data for the period of record 

(figure 22) and were summed as monthly loads expressed 

as chloride and salt (NaCl), assuming that all the chloride 

0

50

100

150

200

250

300

350

Feb. 07

Mar. 07

Apr. 07

May 07

June 07

July 07

Aug. 07

Sept. 07

Oct. 07

Nov.07

Dec. 07

Jan. 08

Feb. 08

Mar. 08

Apr. 08

Month and year

15-month total = 1,720 tons

Monthly load, in tons

0

10

20

30

40

50

60

2/1/07

3/3/07

4/2/07

5/3/07

6/2/07

7/2/07

8/2/07

9/1/07

10/1/07

11/1/07

12/1/07

12/31/07

1/31/08

3/1/08

3/31/08

Date

Daily load, in tons

Figure 22. Daily and monthly salt loads, expressed as sodium chloride, at Pheasant Branch at Middleton, 

Wis. (station 05427948) for February 2007–April 2008.
Changes in Water-Quality Characteristics 25

originally dissociated from NaCl. The monthly loads from 

February 2007 through April 2008 are summarized in table 8, 

and the total load for that period was 1,720 tons of salt. The 

greatest chloride and salt loads were in March and April of 

each year. Daily salt loads exceeded 20 tons per day five times 

during the monitoring period (fig. 22).

Middleton uses a recommended road deicing salt application rate of 300 lbs. per lane mile and used 2,068 tons of salt 

during the record snowfall season of 2007–8 (T. Ginder, City 

of Middleton, Director of Public Works, written commun., 

2009). In the 2008–9 season, Middleton used a more normal 

1,346 tons of salt. In comparison, the Madison Streets Division utilizes a salt application rate of 150 lbs. per lane mile 

(City of Madison, 2006), and Madison applies a calcium 

chloride solution as the prewetting agent and a sand abrasive 

that includes 20 percent salt. Deicing salt is also applied to 

sidewalks, driveways, and parking lots on commercial and 

residential private property. Many commercial property owners hire private contractors who apply salt to the parking lots 

many times (up to 20–30 times) each winter. In a Madison 

survey, salt application rates to parking lots ranged from about 

0.14 to 0.30 tons per acre for each application (City of Madison, 2006). Thus, total salt usage in Middleton is likely much 

greater than just the road salt applications.

Table 8. Summary of monthly chloride and sodium chloride 

loads at Pheasant Branch at Middleton, Wis. (station 05427948) for 

February 2007–April 2008. 

Chloride load Sodium chloride Date (tons) load (tons)

Feb. 2007 11.38 18.8

Mar. 2007 140.56 231.7

Apr. 2007 74.22 122.4

May 2007 19.18 31.6

June 2007 30.19 49.8

July 2007 11.31 18.7

Aug. 2007 55.07 90.8

Sept. 2007 17.59 29.0

Oct. 2007 34.15 56.3

Nov.2007 17.91 29.5

Dec. 2007 41.48 68.4

Jan. 2008 109.93 181.2

Feb. 2008 80.42 132.6

Mar. 2008 199.80 329.4

Apr. 2008 199.18 328.4

Feb. 2007–Apr. 2008 1,042.4 1,718.5

May 2007– Apr. 2008 816.2 1,345.6
26 Effects of Middleton Stormwater-Management Practices on Streamflow and Water Quality, Pheasant Branch

Discussion and Conclusions

 Streamflow and water-quality characteristics for Pheasant Branch changed were influenced substantially by urbanization, stormwater-management practices, and increased precipitation during the 1975–2008 study period. During 1975–2008, 

the Pheasant Branch watershed experienced considerable 

urban growth and increases in impervious area, expansion 

of the watershed that connected previously noncontributing 

areas, and implementation of over 100 BMPs in Middleton 

and Madison. Coincidentally, 1975–2008 was a period with 

increasing annual precipitation and streamflow.

For the study period, the average annual streamflow was 

determined to be 5.19 ft3/s and the average annual baseflow 

was 3.71 ft3/s. The average annual streamflow increased by 62 

percent since 1992, likely as the result of increased impervious 

area, enlarged surface drainage area on the South Fork Pheasant Branch, and increased precipitation. The average annual 

baseflow also increased, but not as the result of the enlarged 

drainage area on South Fork Pheasant Branch, because it lacks 

baseflow. A negative aspect of urbanization in many areas is 

decreased recharge to the groundwater system due to increased 

impervious area. The increase in baseflow in Pheasant Branch, 

however, indicates that the BMPs were beneficial for maintaining baseflow.

The annual flood peaks also increased during the study 

period. The 100-year flood peak discharge was determined 

to be 1,510 ft3

/s for the period 1975–2008. Comparing flood 

frequency values for the period 1975–91 to the values for the 

period 1992–2008, the flood peak discharges for Pheasant 

Branch increased by 37 percent for the 2-year recurrence interval and by 83 percent for the 100-year recurrence interval.

A comparison with an adjacent stream for the same 

period Black Earth Creek at Black Earth, a mainly rural 

stream, had increases in flood peak discharges for the 2- to 

100 year recurrence intervals from 43 to 140 percent. Thus the 

increase in flood peak discharge for Pheasant Branch appear to 

be the result of increased precipitation and urbanization. The 

comparison with Black Earth Creek indicates that the storm 

water management practices have been effective in mitigating 

the effect of urbanization, which generally result in increased 

flood peaks , because Pheasant Branch had less increase in 

flood peak discharge for all recurrence intervals.

The stormwater-management practices have succeeded 

in decreasing the average annual sediment load and phosphorus load to Lake Mendota. These loads decreased in spite 

of increasing annual runoff and flood peaks, which would 

normally produce higher sediment and phosphorus loads. 

The biggest decreases in sediment and phosphorus loads 

have occurred since 2001, when the Confluence Pond began 

operation. Since 2002, the annual sediment load has decreased 

45 percent, from 2,650 ton/yr to 1,450 ton/yr, and the annual 

phosphorus load has decreased 48 percent, from 12,200 lb/yr 

to 6,300 lb/yr. A comparison with other streams that drain into 

Lake Mendota and have sediment and phosphorus data show 

that Spring Harbor Storm Sewer had an 11-percent decrease 

in annual sediment load, and Yahara River at Windsor had an 

18-percent decrease in annual sediment load and a 2.5-percent 

decrease in annual phosphorus load. Prior to the construction of the Confluence Pond, Pheasant Branch had the highest 

annual sediment yield and highest phosphorus yield. During 

2002–8, Spring Harbor Storm Sewer had the highest sediment yield, and Yahara River, the only other stream that has 

phosphorus data, had a higher phosphorus yield than Pheasant 

Branch. 

The Storm Water Quality Plan prepared for the City of 

Middleton by MSA Professional Services (2007) shows that 

Middleton has met the NR 156 requirement of reducing total 

suspended solids by 20 percent for the developed area in 

Middleton. In addition, the city has already met the 40-percent 

reduction in total suspended solids required by 2013 and has 

several alternatives for consideration for further reducing total 

suspended solids. 

Salt usage by the City of Middleton for winter deicing 

of roads can result in concentrations of chloride in Pheasant 

Branch that are toxic to aquatic life. Chloride concentrations 

exceeded the EPA chronic criterion of 230 mg/L many days 

during the winter of 2007 and 2008. Because of the solubility 

of salt, the primary mitigation measure is to reduce salt usage 

by using substitutes and improving application techniques.

Future water-resource-management issues that Middleton 

may consider addressing as urbanization increases are: 

1. finding ways to decrease the dissolved-phosphorus load 

that may be contributed by rural areas and is not trapped 

by the Confluence Pond; 

2. determining how to mitigate the increase in the 100-year 

flood discharges that are the result of urbanization; 

3. evaluating if the current flood plain accurately describes 

the 100-year flood plain commensurate with the higher 

100-year flood peak; and 

4. evaluating how increases in flood peaks and average 

annual streamflow have impacted channel erosion in various reaches of Pheasant Branch.
References Cited 27

References Cited

City of Madison, 2006, Report of the Salt Use Subcommittee 

to the Commission on the Environment on Road Salt Use 

and Recommendations: Salt Use Subcommittee to the Commission on the Environment, City of Madison, 19 p.

City of Middleton 2008, Storm water control ordinance, chap. 

26.0 (June 2009: accessed at http://www.ci.middleton.wi.us/

City/Departments/clerk/ordinances/middch26.pdf.

Corsi, S.R., Graczyk, D.J., Geis, S.W., Booth, N.L., and 

Richards, Kevin D., 2010, A fresh look at road salt: Aquatic 

toxicity and water-quality impacts on local, regional, and 

national scales: Environmental. Science and Technology, 

v. 44, no. 19, p. 7376–7382.

Edwards, T.K., and Glysson, G.D., 1999, Field methods for 

measurement of fluvial sediment: U.S. Geological Survey 

Techniques of Water-Resources Investigations, book 3, 

chap. C2, 89 p. 

Gebert, W.A., Radloff, M.J., Considine, E.J., and Kennedy, 

J.L., 2007, Use of streamflow data to estimate baseflow/

ground-water recharge for Wisconsin: Journal of the American Water Resources Association, v. 43, no. 1, p. 220–236.

Grant, R.S., and Goddard, G., 1980, Channel erosion and sediment transport in Pheasant Branch basin near Middleton, 

Wisconsin, a preliminary report: U.S. Geological Survey 

Water-Resources Investigations Open-File Report 80–161, 

19 p.

Krug, W.R., and Goddard, G.L., 1986, Effects of urbanization 

on streamflow, sediment loads, and channel morphology 

in Pheasant Branch basin near Middleton, Wisconsin: U.S. 

Geological Survey Water-Resources Investigations Report 

85–4068, 82 p.

Krug, W.R., Conger, D.H., and Gebert, W.A., 1992, Flood-frequency characteristics of Wisconsin streams: U.S. Geological Survey Water-Resources Investigations Report 91–4128, 

185 p., 2 pls.

MSA Professional Services, Inc., 2007, Storm water quality 

plan, NR216/NR155 TSS Reductions, (project report to City 

of Middleton): 18 p., accessed at http://www.ci.middleton.

wi.us/city/Departments/works/StormWater/SWMP/Report/

MainReport/Stormwater_Quality_Plan.pdf.

Mullaney, J.R., Lorenz, D.L., and Arntson, A.D., 2009, Chloride in groundwater and surface water in areas underlain 

by the glacial aquifer system, northern United States: U.S. 

Geological Survey Scientific Investigations Report 2009–

5086, 41 p.

Porterfield, George, 1972, Computations of fluvial sediment 

discharge: U.S. Geological Survey Technique of Water 

Resources Investigations, book3, chap. C3, 66 p.

Rasmussen, T.J., Lee, C.J., and Ziegler, A.C., 2008, Estimation 

of constituent concentrations, loads, and yields in streams of 

Johnson County, northeast Kansas, using continuous waterquality monitoring and regression models, October 2002 

through December 2006: U.S. Geological Survey Scientific 

Investigations Report 2008–5014, 103 p.

State of Wisconsin, Legislative Reference Bureau, 2009a, 

Storm water discharge permits, chap. NR 216 of Wisconsin 

Administrative Code and Register: Wisconsin State Legislature, Legislative Reference Bureau, p. 133–148–6.

State of Wisconsin, Legislative Reference Bureau, 2009b, 

Runoff management, chap. NR 151 of Wisconsin Administrative code and register: Wisconsin State Legislature, 

Legislative Reference Bureau, p. 399–408–22.

Steuer, J.J., and Hunt, R.J., 2001, Use of a watershed-modeling approach to assess hydrologic effects of urbanization, 

Middleton, Wisconsin: U.S. Geological Survey WaterResources Investigations Report 01–4113, 49 p.

U.S. Census Bureau, 2011, 2010 census data: accessed March 

2011 at http://factfinder2.census.gov/main.html.

U.S. Department of Commerce, National Oceanic and Atmospheric Administration, 2009, Climatic data—Wisconsin: 

National Climatic Data Center, Ashville, N.C., accessed at 

http://www.ncdc.noaa.gov.

U.S. Environmental Protection Agency, 1988, Ambient water 

quality criteria for chloride—1988: U.S. Environmental 

Protection Agency report 440/5–88–001.

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Wisconsin: U.S. Geological Survey Water-Data Reports 

(published annually).

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Report WDR–US–2007, available at http://wdr.water.usgs.

gov/wy2007/search.jsp

Appendixes 1 and 2
30 Effects of Middleton Stormwater-Management Practices on Streamflow and Water Quality, Pheasant Branch

Appendix 1. Storm Water Runoff 

Control Ordinance Summary (from 

City of Middleton Storm Water Control 

Ordinance, chap 26.0, June 2008)

Storm Water Discharge Quality. 

Land-development activities subject to this ordinance 

shall establish on-site management practices to control the 

quality of storm water discharged from the site and shall meet 

the following minimum standards:

Sediment Control.

1. For new development, practices shall be designed to 

reduce by 80 percent the total suspended solids load 

within storm water runoff based on the average annual 

rainfall record, as compared to no runoff management 

controls.

2. For redevelopment, practices shall be designed to reduce 

by 40 percent the total suspended solids load within storm 

water runoff based on the average annual rainfall record, 

as compared to no runoff management controls.

Storm Water Discharge Quantity.

Land-development activities subject to this ordinance 

shall establish on-site management practices to control the 

volume and peak discharge rates of storm water runoff leaving 

the site. On-site management practices shall meet the following minimum performance standards:

Runoff Rate Control.

1. For new development, storm water management practices 

shall be designed and implemented to maintain postdevelopment peak runoff discharge rates for the 1, 2, 5, 

10, 25, and 100-year 24-hour design storms so as not to 

exceed those rates for each respective design storm under 

predevelopment conditions.

2. For redevelopment, storm water management practices 

shall be designed and implemented to maintain postdevelopment peak runoff discharge rates for the 1, 2, 5, 

and 10- year, 24-hour design storms under predevelopment conditions, so as not to exceed those rates for each 

respective design storm under predevelopment conditions.

Infiltration.

New residential and nonresidential developments must 

implement storm water management practices designed to 

meet the following standards:

1. Infiltration—Residential Development. For residential 

development, practices shall be designed so that the postdevelopment infiltration volume is at least 90 percent of 

the average annual predevelopment infiltration volume 

and/or the effective infiltration area comprise at least 

1percent of the site, whichever is less.

2. Infiltration—Nonresidential Development. For nonresidential development, practices shall be designed so 

that the post-development infiltration volume is at least 

60percent of the average annual predevelopment infiltration volume and/or the effective infiltration area comprise 

at least 2percent of the site, whichever is less.

3. Groundwater Recharge—All Development. In addition, 

infiltration systems and pervious surfaces for both residential and nonresidential development shall be designed 

to meet or exceed the estimated average annual groundwater recharge rate of at least 7.6 inches per year, regardless of the effective area of the infiltration system.
Appendix 2. Erosion Control Summary (from City of Middleton Erosion Control Ordinance, chap. 28, June 2008) 31

Appendix 2. Erosion Control

Summary (from City of Middleton 

Erosion Control Ordinance, chap. 28, 

June 2008)

28.03 Purpose. 

The purpose of this Ordinance is to conserve the soil and 

related resources and control erosion and sedimentation and 

thereby to preserve the natural resources, protect the quality of 

public waters, preserve wildlife, prevent impairment of dams 

and reservoirs, protect the tax base, and promote the health, 

safety, prosperity, and general welfare of the citizens of the 

City of Middleton.

28.05 Requirements for Erosion Control Plan.

Any person who proposes to engage in any land disturbing activities subject to this Ordinance as provided in section 

28.04 shall be required to submit to the City an Erosion Control Plan. The design of all best management practices used in 

an erosion control plan under this ordinance shall comply with 

the following technical standards:

a) Natural Resources Conservation services “Field 

Office Technical Guide, Chapter 4” or its successor;

b) Wisconsin Department of Natural Resources “Wisconsin Construction Site Best Management Practice Handbook” or its successor;

Any other technical methodology approved by the City 

Engineer and the Dane County Conservationist.
Publishing support provided by the U.S. Geological Survey

Science Publishing Network, Columbus Publishing Service Center

For more information concerning the research in this report, contact the

Director, Wisconsin Water Science Center

U.S. Geological Survey

8505 Research Way

Middleton, Wisconsin 53562

http://wi.water.usgs.gov/

Gebert and others—Effects of Middleton Stormwater-Management Practices on Streamflow and Water Quality, Pheasant Branch—SIR 2012–5014