Watershed - Middle Grant River (GP05)
Middle Grant River Watershed

Details

The Middle Grant River watershed covers about 80 square miles in west central Grant County. The topography is gently to moderately rolling land with steep-side valleys and broad ridgetops. The watershed is part of the larger Grant River drainage area that is one of the major contributors of sediment to the Mississippi River. The USGS maintains a flow monitoring station on the Grant River near Burton. Data from this station shows that almost 54,000 tons of sediment was discharged to the river above Burton during 1998 (Holmstrom, et.al., 1998). There are 97.3 total miles of streams in the watershed. There are only a few wetlands in the watershed and they lie next to or very near streams. These wetlands are disturbed by agricultural activities, primarily grazing or cultivation during drier periods. There are no cold water streams or exceptional resource waters in the watershed. There are 42 miles of warm water sport fishery. Hackett Branch was added to the state's list of impaired streams in 1998. The streams and watershed as a whole have been ranked as a medium priority for non-point source pollution and the groundwater is considered vulnerable to potential contamination as a result of non-point source pollution. Blake Fork has been ranked as a high priority for a small-scale non-point source pollution abatement project.

Date  2001

Population, Land Use

The topography is gently to moderately rolling land with steep-sided valleys and broad ridge tops. In certain areas, bedrock outcroppings are readily visible on the stream bottoms and along the stream corridors. Agriculture makes up approximately 90 percent of the land cover. Generally, 55-70% of the landcover in the subwatersheds is in cropland while 21-25% is in pasture. While the hilltops are generally cropped, the stream valleys are pastured and the highly agricultural landscape and steep slopes lend themselves to delivery of high sediment loads to the streams that drain the valleys. Bank erosion is a major problem in the watershed. The steep gradients of the streams prevents buildup of sediment in the streams themselves save for the deeper pools, but the problem is moved downstream to larger, lower gradient systems like the lower Grant River and the Mississippi River. The Grant River has historically carried one of the highest sediment loads in the state, which can be evidenced by the delta of eroded sediments that has developed at the river�s mouth (WDNR, 2001).

Date  2012

Population, Land Use

Agriculture is the main land use in the watershed. Approximately 70 percent of the land use is either cropland or pasture. The watershed's estimated annual soil loss is 7.4 tons per acre per year (Midwest Reclamation Planners, no date). Grant County LCD has ranked this watershed as Grant County's second priority area for erosion control in the county. There are only three municipalities in the watershed; Lancaster (4,242), Patch Grove (204), and Bloomington (761). None of these municipalities are experiencing rapid growth. Each of the municipalities has a public wastewater treatment plant that discharges treated effluent to surface waters and all of these facilities are generally functioning well with no recent significant problems.

Date  2001

Nonpoint and Point Sources

Nutrient enrichment has been a problem in these watersheds. In the late 1980�s, dissolved oxygen levels approaching 0 mg/l were reported following rain events and subsequently resulted in fish mortality (WDNR, 1991). The nutrient enrichment is also evident in the enhanced numbers of fish, particularly omnivores, present in a system. Biologists noted that, in conducting these shocking surveys, it was impossible to capture the shear biomass (numbers of fish). Despite capturing hundreds and even thousands of fish at some sites, biologist estimated that they were only successful in capturing one-third to one-half of the fish present in many of the surveys. The nutrient loads enhance algal and periphyton growth, which then enhances available food for grazers and this pattern is repeated up the food chain. Contrary to the conventional thinking that more fish equates to a healthier system, the enhanced abundance of fish is actually a sign of nonpoint source pollution impact, and while these streams may not necessarily be considered as impaired, it does indicate excessive eutrophication of these systems.

The City of Lancaster has been known to have a significant water quality impact on Pigeon Creek (Fix, 1991). Since 1991, however, Lancaster has undertaken improvements to its wastewater treatment plant and collection system to address this problem. Recent compliance monitoring annual reports submitted by the city and Department inspection reports show the facility to be in good operating condition. The primary problem the facility has now is excessive influent loading during major storm events that has resulted in some bypassing of effluent. The City is reviewing the infiltration problem with its collection system and will be addressing this problem through better maintenance and improvements of that system. Recent whole effluent toxicity testing of the City�s effluent indicated no problems. Lancaster also needs to address potential construction site erosion control and community wide stormwater management issues and problems. As of October 2000, Lancaster is challenging the phosphorus limits in its WPDES wastewater discharge permit. Foremost Foods operates a milk processing plant in Lancaster. This facility currently, (2001), sends its process and sanitary wastewater to the Lancaster wastewater treatment plant. Foremost is proposing to treat its wastewater on-site for discharge of the treated effluent to a tributary of Pigeon Creek.

Date  2012