U.S. Department of the Interior

U.S. Geological Survey

Fact Sheet 2005-3094

July 2005

Prepared in cooperation with the cities of Minneapolis, St. Paul, and St. Cloud, Minnesota, and in collaboration with the Minnesota 

Department of Health, Minnesota Pollution Control Agency, Stearns County, Minnesota, and the Upper Mississippi River Source Water 

Protection Project.

The Value of Hydrologic Data and Interagency Coordination 

in Protecting Drinking-Water Supplies in Minnesota Rivers

Printed on recycled paper

from the point of a potential contaminant 

release to water intakes; the goal is to 

give managers the opportunity to maximize finished water storage and/or to 

close the intake(s). The protection areas 

for Minneapolis, St. Paul, and St. Cloud 

which are by design contiguous with 

one another, have been combined into 

a “Composite Source Water Protection 

Area.” (fig. 1,).

In order to be effective in protecting 

drinking-water supplies the Source Water 

Introduction

The cities of Minneapolis, St. Paul, 

and St. Cloud, Minnesota rely primarily 

on the Mississippi River for their public 

drinking water supplies. In 1996, Congress passed the Safe Drinking Water Act 

(SDWA) Amendments that established 

the Source Water Protection Program. 

These amendments require that States 

prepare Source Water Assessments for 

public water suppliers that draw drinking water from surface waters. In 1998, 

the Minnesota Pollution Control Agency 

(MPCA) provided support to the “Upper 

Mississippi River Source Water Protection Project,” through which the Minnesota Department of Health (MDH) 

and the cities of Minneapolis, St. Paul, 

and St. Cloud, Minnesota collaboratively 

prepared Source Water Assessments for 

each of the cities. 

Although not required by the SDWA 

Amendments, Minneapolis, St. Paul, and 

St. Cloud are currently (2005) developing 

Source Water Protection Plans in collaboration with the MPCA. The focus 

of these plans is the (1) delineation of 

Source Water Protection Areas, (2) identification of potential contaminant threats 

to their source water, and (3) development of management strategies and 

measures in response to these threats.

The delineation of the Source Water 

Protection Areas for Minneapolis, St. 

Paul, and St. Cloud has been completed 

(Minnesota Pollution Control Agency, 

2001). These protection areas include (1) 

an inner high priority area within which a 

contaminant release could pose an immediate threat to public health that could 

require closure of the water intakes, (2) 

an outer area within which a contaminant 

release could pose a longer-term threat 

to public health, and (3) the entire basin 

upstream from an intake. The protection 

areas are based primarly on traveltimes 

Protection Plans need to be based on reliable hydrologic information and coordinated effectively though interagency 

communication. Understanding traveltimes in the streams that flow into the 

Mississippi River is a necessary part of 

the plans because delineation of Source 

Water Protection Areas, particularly 

within the inner area, is based primarily on the transport time of potential 

contaminants to a water intake. Source 

Water Protection Plans were based, in 

Figure 1. Locations of selected river watersheds tributary to the Upper Mississippi River and 

Composite Source Water Protection Area.

�����

����

����

���� ����������

�����

����

�� �

���������� ��

���������

�����������

����

����

����

����

�����

�������� ������

����

������� ����

�������

������

������

�������

�����

��������

������

��������

������

����������

������ ���������

��������

�������

������

������

�����

������

����������

���������

����������

���������

����������

���������

���������

���������

���������

���������

���������

���������

����������

���������

����������

�������� �����������

���������

���������

������

�� �� �� �� ����������

� �� �� �� �� ��������������

� ��������������������������������

�����������������������������

������������

�����������������

�����

���������������

���������

������������

���

���� �����������

����

�������

����

������� ���� ������� ���� ������� ����
part, on results of a study by the U.S. 

Geological Survey (USGS) of traveltimes 

in seven Mississippi River tributaries 

upstream from the cities (Arntson and 

others, 2004). This study was done in 

cooperation with Minnesota Department 

of Health, and the cities of Minneapolis, 

St. Paul and St. Cloud. As described in 

this fact sheet, an accidental release of 

liquid manure in April 2004, upstream 

from the St. Cloud water-treatment facility, demonstrated the value of reliable 

hydrologic information and interagency 

coordination among all levels of government in responding to events that threaten 

supplies of public water.

Estimation of Traveltimes 

Traveltime estimates for streams are 

based on stream velocity, flow conditions, and the physical characteristics 

of the stream channel. Traveltimes also 

vary over time and with stream discharge. 

Increased streamflow decreases traveltime and expands the size of delineated 

source-water-protection areas. Decreased 

streamflow increases traveltime and 

reduces the size of delineated source 

water protection areas. 

Traveltimes for seven of the primary 

streams tributary to the Mississippi 

River, which are within the Composite 

Source Water Protection Area, were 

estimated using equations developed by 

Jobson (1996). Estimation of traveltime 

required information about drainage area, 

river slope, and annual mean discharge. 

Traveltimes were estimated in each of the 

seven tributary streams. As an example, 

the estimated traveltimes for the Sauk 

River are presented in table 1. The 

technique provided a method to estimate: 

(1) the rate of movement of a contaminant through a reach of the river; (2) the 

attenuation of the peak concentration of a 

conservative contaminant with time; and 

(3) the time required for the contaminant 

plume to pass a point in the river (Arntson and others, 2004).

The traveltime estimates were evaluated with the dye-trace study in the 

Sauk River to verify the reliability of the 

equations. The dye-trace was conducted 

by the USGS during the summer of 2003 

(figs. 2 and 3). A harmless luminescent 

dye (Rhodamine WT) was tracked in the 

Sauk River from the city of Rockville 

to the confluence with the Mississippi 

River near the St. Cloud water intakes 

Figure 2. Downstream reach of Sauk River showing selected locations of estimated time of travel 

points.

����

�����

�����������

�����

�����

����

�����

����

�����

�����

�������

�����

����

�����

�����

�����

����

�����

�����

����

���������� ��������

����

������������

���������

����

������

����

������� ���� ���

�����

����

������

�����

����

��������

���

����

����

�������������

����

���� �����

���� ������

����

�����

����

������������

������ �����

��

��

��

��

�� ��

��

��

��

��

��

��

���������� �������������

�����������

�������

�������

������� ������� ������� �������

� � � ���������

� � � � �������������

�������������������������������� � �����������������������������

������������

������������������ ����������������� ��������������

�����������

���������

����

������

����������

����

���������

����

������

������

������

�������� �����

����� ����������� ������������� ������� ��������

������ ��������

������ ���� ���

��������������������

Table 1. Comparison of estimated and measured traveltimes for reaches in the Sauk River 

[ft3/s, cubic feet per second; --, no data]

Distance 

upstream 

from mouth, 

in feet

Measured or 

planned-flow, in 

ft3/s

Traveltime of 

peak concentration, in hours

Traveltime to 

leading edge, in 

hours

Duration of 

solute, in 

hours

Total traveltime to trailing 

edge, in hours

Sauk River - Estimated traveltimes from slug1 at Rockville

County Road 1 328 457 11.9 10.6 4.0 14.6

Veterans Drive 21,800 457 9.4 8.4 3.4 11.8

County Road 121 51,000 457 5.0 4.4 2.1 6.6

County Road 139 (Rockville) 83,000 457 0.0 0.0 0.0 0.0

Sauk River - Measured traveltimes from dye injection at Rockville, June 16, 2003, at 11:15 hours

County Road 1 328 -- 15.5 13.4 7.1 20.5

Veterans Drive 21,800 -- 11.8 9.9 5.6 15.5

County Road 121 51,000 -- 5.9 5.0 3.6 8.5

County Road 139 (Rockville) 83,000 457 0.0 0.0 0.0 0.0

1

 Based on method described by Jobson (1996)
on the Mississippi River, a distance of 

approximately 16 miles. Dye concentrations were measured and tracer-response 

curves were developed to determine times 

of peak concentrations and traveltimes 

(table 1 and fig. 4). Water samples at the 

St. Cloud water intakes on the Mississippi River showed that approximately 

30 percent of the water entering St. 

Cloud’s intake at the time of the study 

was contributed by the Sauk River, even 

though the Sauk River contributed only 

10 percent of the flow in the Mississippi 

River by volume. The disproportionate 

flow at the intake was due to the way the 

Sauk River flow stays near the west bank 

of the Mississippi River as it flows past 

the water intakes.

Figure 3. Dye release to Sauk River. Photograph by J.R. Stark, U.S. Geological Survey.

Planning Efforts Applied to 

an Accidental Release of 

Contaminant

In April 2004, 125,000 gallons of 

liquid cattle manure were accidentally 

released into Mill Creek (figs. 2, 5 and 6), 

near its confluence with the Sauk River, 

which flows into the Mississippi River 

just upstream from the St. Cloud water 

intakes. The events that followed the 

incident are a good example of the importance of reliable hydrologic information 

and of interagency communication and 

cooperation in responding to contaminant 

releases that threaten public water supplies.

As the result of prompt communication and action, staff from the city of St. 

Cloud and Stearns County responded 

quickly to the incident. The local fire 

department coordinated construction 

of an earthen containment dike, limiting releases to Mill Creek. Manure 

that entered the creek traveled 16 miles 

downstream in the Sauk River, to the 

confluence with the Mississippi River, 

just upstream from St. Cloud’s water 

intakes. Estimates of the time that would 

elapse before the contaminants reached 

St. Cloud (16 hours) were provided by 

the USGS, based on traveltime estimates 

(Arntson and others, 2004) and flow 

conditions existing at the time. Based on 

this estimate, water intakes were closed 

as the plume passed. Staff from the Minnesota Department of Natural Resources 

(MDNR) and the city of St. Cloud 

measured movement of the contaminants 

as they passed the intakes. The traveltime estimates were found to be accurate, 

based on fecal coliform testing at the 

intake. The duration of the plume was 

approximately 6 hours at the intakes and 

they were closed for 8 hours. With the 

estimated streamflow of the Mississippi 

River at the time of the spill of 6,300 

cubic feet per second (ft3/s), compared to 

the flow of the Sauk River of 213 ft3/s, 

based on data from USGS gaging stations, the plume was substantially diluted 

in the Mississippi River as it traveled 

downstream in the Mississippi River. 

After the release, staff from the MPCA 

and Stearns County directed cleanup 

activities. In total, an estimated 750,000 

gallons of manure, marl, and water were 

pumped from Mill Creek. The removal 

of the residual manure from the creek 

channel was instrumental in the quick 

recovery of the water quality in Mill 

Creek. Three days after the manure spill, 

dissolved oxygen levels in Mill Creek Figure 4. Measured tracer-responce curve for three Sauk River locations.

Figure 5. Response activities to manure 

release. Photograph by Walter Haas, Minnesota Pollution Control Agency, 2004.

���������������

�������������

��������������

����������������������������������������������

�

�

�

�

�

�

�

����������������������������������������������������������������������������������������

����

������������������������������

����������

������������� �������������

����������������������

�������������

������������������������
returned to normal and water clarity was 

good.

Stearns County has increased educational efforts for management and 

maintenance of Liquid Manure Storage 

Structures (LMSS) as a result of the 2004 

cattle manure release. Currently (2005), 

there are about 705 LMSS in the county. 

However, only 418 of these are permitted by County or MPCA officials. The 

County has modified zoning ordinances 

to ensure that new LMSS meet minimum 

structural setback requirements to protect 

streams and lakes from possible future 

releases of liquid cattle manure (Robert 

grams, such as nonpoint studies, and 

the importance of reliable hydrologic 

information (fig. 7) and the application 

of information and technical tools for a 

coordinated response to a contaminant 

release to protect water supplies. Collaborative source water protection efforts, as 

well as traveltime estimates, provided a 

solid technical basis for responding to the 

release. Interagency communication and 

coordination allowed the city of St. Cloud 

to maximize finished water storage and 

to close its water intake prior to arrival of 

the contaminant plume. The availability 

of traveltime data provided the foundation for Source Water Protection Plans 

for each of the cities and provided an 

important tool in protecting St. Cloud’s 

public drinking-water supply.

SELECTED REFERENCES

Arntson, A.D., Lorenz, D.L., and Stark, 

J. R., 2004, Estimation of travel times 

for several tributaries of the Mississippi River, St. Cloud to Minneapolis, 

Minnesota, 2003: U.S. Geological 

Survey Scientific Investigations Report 

2004-5192, 17 p.

Jobson, H.E., 1996, Prediction of travel 

time and longitudinal dispersion in 

rivers and streams: U.S. Geological 

Survey Water-Resources Investigations 

Report 96-4013, 69 p.

Kilpatrick, F.A., 1993, Simulation of 

soluble waste transport and buildup in 

surface waters using tracers: U.S. Geological Survey Techniques of WaterResources Investigations, book 3, chap. 

A20, 37 p.

Kilpatrick, F.A., and Taylor, K.R., 1986, 

Applications of dispersion data: Water 

Resources Bulletin of the American 

Water Resources Association, v. 22, 

no. 4, p. 537-548.

Kilpatrick, F.A., and Wilson, J.F., Jr., 

1989, Measurement of time of travel in 

streams by dye tracing: U.S. Geological Survey Techniques of WaterResources Investigations, book 3, chap. 

A9, 27 p.

Minnesota Pollution Control Agency, 

2001, Upper Mississippi River Source 

Water Protection Initiative—Integration of Source Water Protection and 

Non-point Management: Minnesota 

Pollution Control Agency Clean Water 

Partnership Diagnostic Phase Project, 

Final Report, April 1997 —September 

2001, 56 p. plus appendixes.

Payne, G.A., 1995, Ground-water base 

flow to the Upper Mississippi River 

upstream of the Minneapolis-St. Paul 

area, Minnesota during July 1988: U.S. 

Geological Survey Open File Report 

94-478, 28 p.

U.S. Army Corps of Engineers, 1994, 

Water available from the Mississippi River at Minneapolis and other 

upstream Minnesota locations during 

low flow conditions: St. Paul Disctict, 

29 p. plus appendixes.

U.S. Army Corps of Engineers, 1997, 

Mississippi River Defense Network 

Spill Response Manual: St. Paul District, 91 p., plus appendixes.

Wilson, J.F., Cobb, E.D., Kilpatrick, F., 

1986, Fluorometric procedures for dye 

tracing (rev.): U.S. Geological Survey 

Techniques of Water-Resources Investigations, book 3, chap. A12, 34 p.

—J.R. Stark, A.D. Arntson, U.S. Geological Survey; and D.L. Brostrom, David 

L. Brostrom Consulting Services

Figure 6. Response activities showing Mill Creek. Photograph by Walter Haas, Minnesota Pollution Control Agency, 2004.

Figure 7. Streamflow measurement, Sauk 

River. Photograph by Katie Barnella, U.S. 

Geological Survey.

L. Sip, Stearns County Environmental 

Services, electronic communication, 

2005).

This incident provides a good example 

of the social benefit of planning pro-