Cooperator: Wisconsin Department of Natural Resources
Project Chief: Judy A. Horwatich
Location: Statewide
Project Number: BQY24
Period of Project: July 2001–Continuing
updated 2/20/07
Problem
Wisconsin municipalities are using urban runoff models to help them prepare
stormwater management plans. Planners and engineers use the models to identify
the most important sources of pollutants and quantify the benefits of different
management alternatives. The Source Loading and Management Model (SLAMM) is one
of the models recommended for stormwater planning by the WDNR.
All watershed
models should be calibrated before they are applied. Large errors in flow and
pollutant concentrations can result if the model is not adjusted as much as possible
to the places it will be used. In most cases the municipalities will not have
the resources to collect the necessary flow and pollutant concentration data.
Fortunately, enough stormwater data has been collected to adjust SLAMM for use
by municipalities in Wisconsin.
Objective
The objective of the project is to calibrate and verify the SLAMM model with
the stormwater flow and pollutant concentration data available from urban studies
conducted in Wisconsin.
Approach
The USGS in Wisconsin has collected flow and pollutant concentrations from
source areas and at the end of the pipe for several projects. Land use and development
characteristics, such as percent connected imperviousness, were determined for
each study area. All the above information is needed to calibrate and verify
SLAMM.
There are three steps involved in calibrating
SLAMM. First, the predicted runoff volumes should be adjusted to match the values
observed at the end of the pipe. Second, the predicted particle solids loads
should be adjusted to match, as much as possible, the observed particle solids
loads at each sites. The last step is to calibrate pollutant loads, such as total
and dissolved sediment, nutrients, metals, and organics.
All the files created by
the calibration will be placed on the USGS Web page.
There is a link from the WDNR Web page to the USGS Web page.
Progress (January 2006 to June 2006)
The model
is being calibrated and verified on settling devices and street sweeping. The
model will be used to help write the WDNR technical standards. Files are available
on the USGS Web page http://wi.water.usgs.gov/slamm/index.html
Plans (July 2006 to December 2006)
Complete calibration and verification modeling on settling devices and
street sweeping. The street dirt accumulation routines for street dirt have been
modified. New street dirt delivery files will be developed and made available
on the web. Review runoff curves and concentration data for streets, lawns and
parking lots.
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