Cooperator: Wisconsin Department of Natural Resources
Project Chief: William R. Selbig
Location: Dane County
Project Number: BQY19
Period of Project: May 2001–September 2006
updated 2/20/07
Problem
The City of Madison is required to control the quality of stormwater runoff as
part of the National Pollution Discharge Elimination System (NPDES). Previous
studies have indicated that runoff from street surfaces is a major contributor
to pollution in the city (Waschbusch and others, 1999). One way to control
roadway runoff is to use street sweeping to remove pollutants before they are
entrained in runoff. This option may be preferable to structural Best-Management
Practices (BMPs) since structural BMPs can be expensive and often require land.
In addition, the city already conducts street sweeping and may only need to
modify their sweeping practices.
Objective
The primary objective of this project is to determine if the dirt load on residential
streets is reduced by various street-sweeping scenarios and if so, to what degree.
Water-quality samples will be collected from three basins to determine if water-quality
benefits are realized by the street-sweeping program, and to what extent. The
water-quality sampling results from these basins and the street-dirt load data
will be used to estimate the benefits that may be achieved using other street-sweeping
programs.
Approach
This study will use a paired basins approach, meaning that data will be
collected from four basins and then compared to each other. One basin will be
the “control” basin and will have minimal sweeping. The other three
basins (the “test” basins) will have different sweeping regimens
implemented. Two basins will utilize two different street sweepers provided by
Elgin, Inc. and will be swept once per week. The remaining basins will be swept
on the same schedule as other areas of Madison, approximately one time per month,
and will be completed using existing equipment. Data from the test basins will
be compared to data from the control basin.
The USGS will collect vacuum samples
once a week from four study basins for the duration of the study. During sweeping
periods, samples will be collected immediately before street sweeping occurs
and immediately after. The USGS will dry, sieve, and weigh the vacuum samples.
The samples will be sieved into particle-size fractions ranging from <63 µm
to >2,000 µm in an effort to further characterize street dirt. In addition
to the street-dirt sampling, the control basin and the basins utilizing Elgin
street sweepers will have water-quality samples collected and compared. These
basins will be equipped with monitoring stations to collect discharge and water-quality
data.
A street sweeper using mechanical broom and vacuum technology passes through a residential street in Madison, Wis. |
Progress (January 2006 to
June 2006)
Continue to monitor water quantity and quality at the control and test basins.
A rough draft summarizing only the street dirt data was written with accompanying
graphs and illustrations. The water-quality portion of the study will not be
summarized until all data have been collected. The deteriorating equipment shelter
at the control basin was replaced with a new aluminum shelter.
Plans (July 2006 to December 2006)
Continue to monitor water quantity and quality at the control and test
basins through September 2006. Water-quality data will be summarized and tabled
for inclusion in draft report. All instrumentation will be removed unless additional
studies warrant them to remain in place.
Reports
Scientific Investigations Report, September 2007.
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