Watershed - Platte River (GP02)
Platte River Watershed

Details

The Platte River watershed covers 198 square miles in central and east-central Grant County with a small portion in extreme western Iowa County. It has an area of about 194 square miles making it the second largest watershed in the basin. The Platte River is the primary waterbody in the watershed. The river's historical records for the river record it to be deep enough to allow steamboats to ply its lower reaches. The upper reaches of the watershed are on Military Ridge, where the land is rolling and well suited to cultivation. The rest of the watershed's topography consists of narrow ridgetops, and steep slopes down to a narrow valley floor. The ridgetops are usually cultivated, while the steep valley slopes have been left in woods, similar to the pre-settlement condition. There are about 215 stream miles in the watershed. There are 30.8 miles of cold water trout streams, approximately 60 miles of warm water sport fishery streams, 48.2 miles of warm water forage fishery streams, and 3.2 miles of limited aquatic life streams. The existing biological use of the remaining stream miles have not been determined, but are assumed to be full fish and aquatic life waters. Portions of four streams in the watershed, totaling 10.5 miles, are currently on Wisconsin's list of impaired waters, the 303(d) list. Those streams are Culver Branch, a short reach of Leggett Creek, a portion of Martinville Creek, and McPherson Branch. Each are on the list due to instream habitat impairment caused by nonpoint sources of pollution. The Platte River, Crow, Culver, Lee, Leggett, and McPherson Creeks have been ranked high for nonpoint source pollution abatement projects.

Date  2001

Population, Land Use

There are three municipal Wisconsin wastewater discharge permitted facilities in the watershed. They are Orchard Manor with a discharge to a tributary of Austin Branch, Dickeyville (931) with a discharge to a tributary to Indian Creek, and Potosi-Tennyson that discharges to a wetland in Pool 11 of the Mississippi River. None of these are considered large or major municipal dischargers. Dickeyville is growing at a relatively slow rate, so urban nonpoint source pollution from construction sites and stormwater runoff is not a major concern. Care still needs to be taken to properly control erosion from construction sites in the community. The wastewater treatment plants in the watershed do not constitute a threat to water quality as long as they are properly operated and maintained. Public recreation in the watershed is limited by lack of public lands. Access to streams is scattered throughout the watershed and at road crossings.

Date  2001

Nonpoint and Point Sources

Agriculture is the dominant land use in the watershed and over 70% of the watershed's area is actively farmed (Fix, 1991). The watershed has many acres of intensively cropped farmland on highly erodible land. Stream bank erosion, from overgrazing streambanks or flooding, is also a major problem (Grant County, 1997). The Platte River watershed has one of the highest livestock concentrations in Wisconsin (ibid.). Runoff from problem barnyards and feedlots add to the sediment and nutrient problems in receiving surface waters. Two best management practices can be implemented to protect streams. One is providing stream buffers to stabilize stream banks, provide habitat, and filter out pollutants which otherwise would reach the stream (Lyons et. al., 2000b). A second practice that provides a similar result is rotational grazing (Lyons,et.al., 2000a). Grant County LCD and the county office of the NRCS jointly initiated a USDA EQIP project in the Platte River Watershed (Environmental Quality Incentives Program), in the summer of 1998. Average soil loss for cropland in the Platte River watershed is estimated at eight tons/acre/year (Grant County, 1997) which compares with the tolerable (T) or target goal for soil loss in the watershed of five tons/acre/year. The water resources objectives of the Platte River watershed EQIP project are to obtain water quality, fish and wildlife habitat improvements by reducing sheet and rill erosion, streambank erosion, and manure and cropland runoff through a variety of farm management best management practices, including contour farming, conservation tillage, rotational grazing, grade stabilization structures, streambank stabilization, sediment basins, filter strips, manure storage, nutrient management, fencing and livestock exclusion (ibid.).

Date  2001

Nonpoint and Point Sources

Nonpoint Source Pollution - Based upon watershed reconnaissance conducted in the fall of 1997 and spring of 1998, monitoring streams in the watershed, and professional judgment of DNR staff, there are still a number of land management problems, including soil erosion from cultivated fields, overgrazing of streambanks, and exposed and eroding streambanks, around smaller cool and cold water streams in the upper portion of the Platte River watershed. The current work involved in the Platte River EQIP project should help to address some of the problem sites in the watershed. However, there is a continued need to consider these streams for small-scale nonpoint source pollution abatement projects as well. A major reconstruction of US Highway 151 from Dickeyville to Belmont is scheduled to begin in the year 2002. Sediment coming from the site could threaten instream habitat and fisheries of nearby streams if adequate erosion control measures are not installed and properly maintained. Because of the topography of the area such measures may need to go beyond the standard Wisconsin Department of Transportation measures. The stream in this watershed potentially threatened is Indian Creek near Dickeyville. There are three municipal Wisconsin wastewater discharge permitted facilities in the watershed. They are Orchard Manor with a discharge to a tributary of Austin Branch, Dickeyville (931) with a discharge to a tributary to Indian Creek, and Potosi-Tennyson that discharges to a wetland in Pool 11 of the Mississippi River. None of these are considered large or major municipal dischargers. Dickeyville is growing at a relatively slow rate, so urban nonpoint source pollution from construction sites and stormwater runoff is not a major concern. Care still needs to be taken to properly control erosion from construction sites in the community. The wastewater treatment plants in the watershed do not constitute a threat to water quality as long as they are properly operated and maintained.

Date  2001