BLACK OTTER LAKE DISTRICT

Transcription

1 BLACK OTTER LAKE DISTRICT Storm water Action Plan Action Plan submitted for UW-Madison Course JDD001 #41967 Great Lakes Water Stewardship Institute 2012 Hortonville Area School District Hortonville High School Fox West Academy Patrick Koss Dan Lundstrom Action Plan BOL_storm_2012_v1 Updated Introduction 17 August 2012

2 Introduction In 1848, Alonzo Horton constructed a dam on the Black Otter Creek for providing power to a sawmill. In the year that followed, the millpond filled, giving Outagamie County its first lake, Black Otter Lake, and a new village called Hortonville (Ryan 1911). The lake aged, and aquatic plant growth became an issue in the 1950s. Concerned citizens formed the Black Otter Lake District in 1976 and for the past thirty-six years, they have been managing the lake (Wentland 1982, Wentland 1992, Cason 2003, and STS Consultants 2008). The district has completed four different studies on rehabilitation, but it has never addressed storm water runoff from the school campus. The purpose of this paper is to provide guidelines for an action plan that students and staff from the Hortonville Area School District (HASD) can complete to reduce the effects of school campus runoff on Black Otter Lake. Background Black Otter Lake lies in the Northwest corner of Outagamie County in the village of Hortonville, Wisconsin (N W ). A slot-board dam on the Black Otter Creek that is filled from a 10,043-acre watershed forms the 75-acre impoundment (Wentland 1992). Figure 1 Aerial view of Black Otter Lake, the Village of Hortonville, WI courtesy of NAVTEC and Microsoft Corporation. 1

3 Figure 2 Quadrangle map of the Black Otter Lake delineated watershed in Outagamie County, WI that measures 10,043 acres (Cason 2003). The history of the Black Otter Lake has been one of eutrophication. The first signs of aging appeared in 1956 when there was a decline in wildlife and fish and an increase in aquatic plants and siltation (Wentland 1982). The Black Otter Creek Watershed Project of 1956 attempted to improve the conditions of the lake by dredging and increasing habitat for fish and game. In the 1960 s the first recorded fish kill initiated drawdown strategies for improved dissolved oxygen levels. Using the Public Inland Lake Protection and Rehabilitation Act of 1974, the village of Hortonville formed a Lake Rehabilitation District, later called the Black Otter Lake District (BOLD). The district produced feasibility and rehabilitation studies that were completed by 1981 (Wentland 1982). The studies pointed to high phosphorus levels, depleted dissolved oxygen levels, dense macrophyte growth and excessive sediment accumulation as the main threats to the lake. The methods of management of the threats were sediment removal, aeration, drawdown, and aquatic plant control by herbicide and harvesting. The dredging was completed in 1989 and the lake was refilled in The dredging, digging of five sediment ponds, and aeration increased the depth of the lake and the levels of dissolved oxygen, while it reduced the sediment accumulation of the lake (Wentland 1992). A by-product of the dredging was the reduction in competition from native plants, which provided an 2

4 opportunity for invasives to become established (Kalff 2001). Mechanical harvesting was used in the 1990s to reduce plant growth, but a caveat to the method is that it promoted the spread of Eurasian Water Milfoil (EWM) (Kalff 2001). By 2003, EWM and Curly Leaf Pondweed (CLP), both exotic invasive species (Aquatic Plants ), had become major components in the macrophyte population of the lake. Invasive species, EWM and CLP, were significantly reduced by a 2008 drawdown and chemical application (STS 2008). Currently the lake is highly eutrophic with high nutrient levels, dense macrophyte growth, and sedimentation. Sedimentation By the mid-1980 s, Black Otter Lake s depth was hindering boating. The changes in depth were linked to sediment and nutrient runoff (Wentland 1992). As part of a rehabilitation plan, greater than 600,000 cubic feet of sediment was removed from the lake by dredging in In addition, five sediment ponds were dug on the north and south inlets of the lake to reduce the amount of sediment reaching the lake (see Figure 3). Figure 3 Aerial view of Black Otter Lake, Hortonville, WI outlining sediment pond placement from 1989 dredging. Aerial view courtesy of NAVTEC and Microsoft Corporation. 3

5 The Hortonville Area School District has campuses in Hortonville and Greenville, WI. The campus in Hortonville drains its storm water to the storm sewers near Alonzo Park at the corners of South Warner Street and East Main Street. This storm water is part of sedimentation problem affecting the north inlet of Black Otter Lake. Hortonville High School was constructed in the 1950 s on part of a wetland with an intermediate stream running through it. The fields consistently have standing water that empties directly into a sewer line by the fields. Hortonville Middle School was constructed in the 1990 s on higher ground. In times of heavy rain, the water flows unabated to the storm sewer lines. Figure 4 Aerial view of the Hortonville campus of the Hortonville Area School District (HASD) in Hortonville, WI. Storm water from these lands empties at the storm water outlet in Alonzo Park. Aerial view courtesy of NAVTEC and the Microsoft Corporation. Action Plan Objective The objective of this action plan is to reduce the amount of sedimentation from HASD campus lands that flow into Black Otter Lake via the storm water outlet in Alonzo Park. Appendix A will address Hortonville High School s portion and Appendix B will address Fox West Academy s (FWA) portion (FWA is housed in Hortonville Middle School). 4