Project Detail

Cedar Lake and Half Moon Lake TMDL Implementation Assessments

Purpose

WDNR, USACOE, Polk County Land and Water Conservation Department and the Cedar Lake Protection and Rehabilitation District are implementing a project to assess internal phosphorus loading processeses in polymictic lakes with high internal phosphorus loadings. The processes include anoxic phosphorus release from deep sediments, ph induced and oxic phosphorus release from littoral sediments and associated transport processes to the pelagic zone and cyanobacteria transport of phosphorus from deep sediments into pelagic photic zone. WDNR, ACOE and the City of Eau Claire are implementing the Half Moon Lake TMDL. This project is to assess the whole lake treatment of curly leaf pond weed and eurasion water milfoil.

Objective

The Cedar Lake TMDL required widespread BMP implementation through the Horse Creek Lakes priority watershed project and whole lake mixing by aeration. After implementation the lake remains to have a significant internal phosphorus load as growing season total phosphorus levels increase by a factor of 2-4 from April to September. This project will assess watershed phosphorus loadings and the three major sources of internal loadings in 2009 and 2010. The project requires staff to be monitoring on Cedar Lake aapproximately 2 days per week. Multiple monitoring activities will be employed at multiple sites within the lake and watershed. Staff will be assisted by ACOE staff and local citizen volunteer monitors. (Detailed study design available on request). Half Moon Lake Curly Leaf Pond Weed has been determined to be 20% of the annual phosphorus budget for Half Moon Lake. TMDL implementation requires a high level of CLP control if the TMDL is to be achieved. A whole lake herbicide treatment for CLP will be conducted in 2009, 2010 and 2011. The project includes multiple monitoring strategies for assessing changes in water quality, aquatic macrophyte community biomass and assemblage, annualized sediment phosphorus dynamics and residual herbicide breakdown rates.

Outcome

Revised TMDL management recommendations to achieve water qualtiy goals. Monitoring results a critical to developing management objectives to control internal phosphorus load and assess additional watershed phosphorus loading reductionsl Half Moon Lake Assess if CLP reductions result in decreased total phosphorus concentrations and associated reduction in chlorophyll a concentrations and improved in lake habitat conditions throught increased abundance of native aquatic plant species.

Project Type

TMDL/303d Projects

Project Sub Type

Evaluate for Delisting

Project ID

WCR_14_CMP10 ATTAINS

Year Started

2009

Status

Active

Reports and Documents

WCR_15_BUDGETS