Jennings Bay-Painter Creek Projects

Original project completed in 1985; upgrade completed in 1997

Project Type:

Project Status: 
Completed
About this project: 
Water quality data gathered since the mid 1970s indicates that the water quality of Jennings Bay, located at the northwest end of Lake Minnetonka, is inferior to that of other portions of the lake. Point and non-point source phosphorus loading is the limiting nutrient factor for algae growth.

Historically, the water quality of Painters Creek has been degraded due to Maple Plain wastewater treatment plant discharge and agricultural land uses. This has adversely impacted Jennings Bay as well and is strongly suspected to be the cause for a significant build-up of nutrients in Jennings Bay sediments. Although the Maple Plain wastewater treatment plan discharge ceased in 1986, Jennings Bay continues to show degraded water quality. It is believed that the 'internal' phosphorus loading from the bottom sediments is significantly responsible along with continual external loading.

Jennings Bay has an estimated phosphorus loading of 4,800 lbs. per year (16 lbs./acre of lake surface area). Painters Creek non-point source loading contributes nearly 50% of the total loading to Jennings Bay. Assuming 'natural' phosphorus loading conditions, the water clarity (secchi disc) reading for Jennings Bay would be estimated at 10 feet. Data of record indicate an average observed secchi depth of 2 feet.

Seven construction areas were identified and constructed in 1985 as part of the Upper Watershed Improvement Project CP-5 for Painters Creek. Overall, the 1985 Painters Creek Project increased storage capacity by approximately 900 acre-feet for major runoff events and substantially reduced discharges to Jennings Bay.

Additional data acquisition and analysis was obtained in 1995 and 1996 to accurately estimate the internal and external phosphorus loads. To estimate the external phosphorus load, continuous automated flow monitoring and sampling for total and ortho-phosphorus were collected at Painters Creek. A total of 6 (20' deep) soil borings were taken to analyze the soil of the Painters Creek bed upstream of Painters Creek for geotechnical disposal purposes.

The following parameters were taken at Jennings Bay to estimate the internal phosphorus loading: temperature, dissolved oxygen, total and ortho-phosphorus, total iron, secchi depth, alkalinity and pH. Seventeen (10' deep) borings were taken in Jennings Bay for sediment analysis. This data aids in determining the extent of nutrients in the Bay's sediments, and the feasibility of Jennings Bay dredging and disposal options.

Repair and maintenance of the existing structures and sedimentation basins are expected to improve the water quality of Painters Creek. Cost estimates for maintenance and repair of the construction areas, plus data acquisition and analysis is estimated at $201,550.

Painter Creek Project Specifications

  • Location: Orono, Minnetrista, Independence & Medina, Minnesota
  • Completed: Original completed in 1985; upgrade completed in 1997
  • Engineers: Original (Hickok & Associates); Upgrade (Wenck Associates, Inc.)
  • Cost: $1,000,000 (total)
  • Funding: MCWD Ad Valorem Tax
  • Outlet structures: Lake Katrina and Pond 937
  • Sediment basins: South Katrina and Painter Marsh
  • Channel Clearing & Widening:
    • Katrina Lake and Painter Wetland - 4,000 lineal feet; 1,840 cubic yards excavated
    • South Katrina Basin - 5,000 square; expand to double volume
    • Painter Basin - 16,300 square feet; expand to triple volume