WATER QUALITY MONITORING PLAN FOR THE ST. CROIX RIVER, MINNESOTA AND WISCONSIN: 2006

Don Hansen, U.S. Geological Survey
Sue Magdalene, St. Croix Watershed Research Station
Kent Johnson, Metropolitan Council-Environmental Services
Craig Affeldt, Minnesota Pollution Control Agency
Brenda Moraska Lafrancois, National Park Service
Travis Thiel, Washington Conservation District

In 2005, the St. Croix Basin Team, in cooperation with the Wisconsin Department of Natural Resources and the U. S. Geological Survey, developed a water quality monitoring plan for the entire St. Croix River basin. The purpose of this plan is to describe a coordinated water quality monitoring effort within the St. Croix River basin. The plan will be used as a guide for future monitoring and to measure progress toward the 20-percent phosphorus load reduction goal set by the St.Croix Basin Team. The plan objectives are: 1)Determine nutrient and sediment concentration trends and loads for the mainstem of the St. Croix River and Lake St. Croix; 2)Determine nutrient and sediment loads for the selected tributaries used to track progress on tributary nutrient management goals; 3)Determine trends in biological indicators in Lake St. Croix and Lake Mallalieu; and 4)Provide information used in the development and modification of mainstem and tributary nutrient models, which are used to asses various nutrient management scenarios.

The geographic priority suggested by the monitoring plan is the lower half of the St. Croix River basin because the most immediate development pressures are occurring in the southern part of the basin. Lake St. Croix serves as a water quality integrator for the entire basin. The plan listed 53 sites monitored in 2006 and 32 ideal monitoring sites. The plan identified gaps between the current and ideal monitoring networks, and recommended priorities for future additional monitoring.