Stillwell Creek TMDL

Purpose

Squaw Creek and Stillwell Creek are tributary streams of the Upper La Crosse River Basin, located in Monroe County in west-central Wisconsin. The streams are within the boundaries of Fort McCoy, a federal military facility. Both Squaw Creek and Stillwell Creek are classified as “water quality-limited” and have been placed on Wisconsin’s list of water bodies in need of restoration, a list prepared in accordance with Section 303(d) of the Clean Water Act and known as the “303(d) list.” The Wisconsin Department of Natural Resources (WDNR) listed Squaw Creek due to temperature impairments. WDNR listed Stillwell Creek due to temperature and sediment impairments. Stillwell Creek was added to the 303(d) list in 2003, but there was an error in listing the precise segment of the creek. The State of Wisconsin has since provided information to USEPA to correct this information.

Objective

Stillwell Creek is a 4.7-mile trout stream with a gradient of 28 feet per mile that drains an area of approximately five square miles. A 2.2-mile segment downstream from the cranberry operation supports a class III trout fishery whereas the segment upstream of the cranberry operation is classified as a class II trout fishery. The segment of the creek downstream of the cranberry operation is considered impaired because the fish community is rated poor as measured using the Index of Biotic Integrity (IBI). The low IBI scores are believed to be due to high temperatures, and degraded habitat which is reflected in an elevated fine sediment count. Water temperature increases cause cold water communities to suffer a variety of ill effects, which can range from decreased spawning to death. Dissolved oxygen sags can also be influenced by an increase in the water temperature because less oxygen is soluble as temperature increases. Water temperature increases can be caused as a result of stream bank erosion, widening the river channels, which exposes more of the river water to direct sunlight. Sedimentation reduces the suitable habitat for fish and macroinvertebrate communities. Filling-in of pools with sediment reduces the amount of available cover for juvenile and adult fish. Sedimentation of riffle areas reduces the reproductive success of fish by reducing the exposed gravel substrate necessary for appropriate spawning conditions. Sedimentation also affects macroinvertebrate biomass (fish food source) which tends to be lower in areas with predominantly sand substrate than in a stream substrate with a mix of gravel, rubble and sand. Sedimentation (particularly in the case of fine sediments which remain in suspension longer) also causes elevated turbidity, which reduces the penetration of light necessary for photosynthesis in aquatic plants, reduces feeding efficiency of visual predators and filter feeders, and lowers the respiratory capacity of aquatic invertebrate by clogging their gill surfaces. In addition, other contaminants such as nutrients (phosphorus) attached to sediment particles can be transported to lakes and streams during runoff events. Nutrient enrichment can contribute to dissolved oxygen sags by stimulating aquatic plant growth and their oxygen consumption demands.

QA Measures

Run Project Summary Report

TMDL/303d Projects
Approved TMDL
Stillwell Creek TMDL
2006
Complete
 
Reports and Documents
Stillwell Creek Land Use Map
Stillwell Pond Cranberry Beds, Ft. McCoy
Data Documentation Impaired Waters Documentation, Changes
Trout Stream Classification Checklist, survey on file at Fort McCoy.
 
Activities & Recommendations
TMDL (USEPA) Approved
TMDL Development for Squaw Creek and Stillwell Creek, Wisconsin
 
Waters