Mallalieu Lake tmdl development monitoring

Purpose

The purpose of this project is to collect in-lake water quality samples to be used in the development of a TMDL for Lake Mallalieu, which is on the 303d list. The lake is listed for pH exceedances and poor water quality due to phosphorus. Water quality is currently being collected by DNR staff as part of the Tier 1 non LTT monitoring program from the Willow River above Lake Mallalieu. Continuous flow is also being monitored in the Willow River by USGS. The combination of load monitoring from the river site and in-lake monitoring will be used to develop a phosphorus TMDL. This TMDL monitoring project was one of four conducted in WCR during 2006-07. Lake and stream sampling was conducted bi-weekly and begin in June 2006 and continue until September 2006.

Objective

Lake Mallalieu is a man made riverine lake located within the channel of the Willow River. Since 2004, Lake Mallalieu and an upstream reach of the Willow River have been included on the Environmental Protection Agency’s (EPA) 303(d) impaired waters list. The lake is designated as high priority for eutrophication and ph impairments due to excess phosphorus, while the upstream reach of the river is a low priority for dissolved oxygen impairments. The river’s designation is due to excess phosphorus and biological oxygen demand (BOD). The Clean Water Act and USEPA (United States Environmental Protection Agency) require Total Maximum Daily Load (TMDL) goals be developed for 303(d) listed waters. In light of this, Wisconsin’s Department of Natural Resources (WDNR) is required to prepare a phosphorus TMDL for Lake Mallalieu and its associated drainage area. Development of the TMDL goals has required monitoring of annual phosphorus loading upstream of the lake and of in-lake water quality conditions.

Outcome

Monitoring of phosphorus loads occurred in years 1991, 1999, 2003, and 2006. After monitoring was complete, a land use model using the Soil and Water Assessment Tool (SWAT) was developed to evaluate the effect of land management changes on the quality of water entering Lake Mallalieu (Almendinger 2008). In-lake water quality was modeled using the BATHTUB model (Oldenburg 2008). Information gathered from both the SWAT and BATHTUB models has been used to develop in-lake load reduction goals for the Lake Mallalieu/Willow River TMDL. Due to excessive phosphorus, Lake Mallalieu is not currently meeting water quality criterion as defined in NR 102..04 (1); Wisconsin Administrative Code. In short, Lake Mallalieu currently cannot support a warm water sport fishery nor does it serve as a ‘high quality” recreational resource for its users.

QA Measures

Run Project Summary Report

TMDL/303d Projects
Refine Load Estimates
Mallalieu Lake Monitoring
2006
Complete
 
Reports and Documents
TMDL Implementation Plan
Condition Assessment Report
Condition Assessment Report
MALLALIEU LAKE FY07 MONITORING PROPOSAL
MALLALIEU LAKE SENSITIVE AREA DESIGNATION - ORIGINAL MAPMALLALIEU LAKE SENSITIVE AREA DESIGNATION - ORIGINAL MAP
MALLALIEU LAKE SENSITIVE AREA DESIGNATION - WILDLIFE AND FISH USE OF AQUATIC PLANTS
Table of Contents
DESIGNATION OF SENSITIVE AREAS, LAKE MALLALIEU, ST. CROIX COUNTY
Data Documentation Lake Mallalieu Impaired Waters Listing Documentation, St. Croix County
 
Activities & Recommendations
Monitor or Propose 303(d) Listing
Continue monitoring the Willow River, St. Croix County for sediment, phosphorus loading related to an impaired waters listing.
Monitor Watershed (Status,Sources,Impairments)
Basic waters inventory monitoring should be conducted on the seven waters so designated in this watershed.
 
Waters