Hickory Grove Lake is a 100-acre constructed lake in Story County, Iowa, with a lake to watershed ratio of 40:1. In recent years, the lake has experienced a number of rain event-driven water quality problems that are negatively affecting this resource. Sedimentation in arms of the lake has impacted recreation and surface run-off has led to gully erosion, debris, and nitrogen spikes in samples collected from the watershed. Additionally, the beach at the lake has been listed as impaired due to high concentrations of indicator bacteria. While the fishery remains relatively healthy, carp have limited vegetation in the lake. Aquatic vegetation is important fish habitat and helps keep water clear by removing nutrients from the water column and minimizing sediment re-suspension due to wind and wave action in nearshore areas.
Many project partners have been involved in improving the health of Hickory Grove Lake and its watershed. Major partners include:
Iowa Department of Natural Resources
Story County Environmental Health
Natural Resources Conservation Service
Iowa State University
Iowa Department of Agriculture and Land Stewardship
Iowa Learning Farms
Prairie Rivers of Iowa
Watershed Improvement Review Board
Story County Soil and Water Conservation District
Starting in 2008, a watershed technical advisory team was formed to discuss water quality improvement efforts at the lake. The NRCS received a development grant in 2008 to determine critical areas within the watershed for restoration and complete a land use assessment. In 2011, Iowa State University also received a planning grant to develop a watershed management plan for Hickory Grove Lake. This plan outlined strategies for managing bacteria levels at the beach and included recommendations for goose control, lake draw-down, sediment removal and a fishery renovation.
SCC received a WIRB (Watershed Improvement Review Board) grant and partnered with the DNR Lakes Restoration team to complete a handful of needed improvements in the watershed:
livestock exclusion from main tributary
replacement of unpermitted septic systems in watershed (cost-share program)
These projects were completed in 2016 and helped minimize new sediment and nutrients being delivered to the lake.
These efforts along with continued partnership with the NRCS for watershed water quality and awareness significantly reduced the amount of sediment and bacteria entering the lake. Once addressing issues in the watershed, it was time to focus efforts on water quality improvements in the park prior to beginning a lake renovation.