DNR Lake Number: 70007200*
Surface Area: 416 acres
Average Depth: 10 feet
Maximum Depth: 43 feet
Ordinary High Water Level: 903.9 feet above sea level
Connectivity to other waterbodies: Water flows into Upper Prior from Spring Lake through the Spring Lake channel and out of Upper Prior into Lower Prior Lake.
Watershed Area: 16,038 acres
Public Boat Access: Located on the southern end of Upper Prior off of Dewitt Ave.
Impairment Status: Impaired for Mercury,* Biota,** and Excess Nutrients***
Bridge Clearance: The elevation at the bottom of Wagon Bridge (bridge under Highway 21) is approximately 911.5′. Subtract the current lake elevation from 911.5′ to get the approximate clearance.
*Mercury impairments are not handled at the local government level. The State of MN has a TMDL they are following here.
**Biota impairments are not handled at the local government level. The State of MN addresses impaired biota by examining the interactions of numerous physical, chemical, and biological processes that define community composition. Biological impairments can be driven by natural or unnatural changes to one or many components of these systems. Biological impairments differ from some traditional water quality impairments in that the impaired biotic communities are indicators of disturbance rather than causes of disturbance. Biological impairments are commonly caused by stressors that are not considered conventional pollutants. These include stressors such as degraded habitat or altered hydrology. Minnesota utilizes the process of stressor identification developed by the EPA to identify the dominant stressors.
***See the TMDL study for more information.
The following graphs represent the annual averages between May 1 and September 30.
- Spring Lake-Upper Prior Lake TMDL Report (link to MPCA site)
- Spring Lake-Upper Prior Lake TMDL Implementation Plan (2012)
- Upper Prior Lake In-Lake Phosphorus Management Plan (2017)
- PLSLWD Upper Watershed Assessment (2010)
- Prior Lake Historic Elevations Graph 1970-2015
- 1993 Diagnostic & Feasibility Study of Spring and Prior Lakes
Aquatic Vegetation Reports
- 2017 Upper and Lower Prior Lake Curlyleaf Pondweed Report
- 2008 Curlyleaf and Eurasian Watermilfoil Growth Potential based on Lake Sediment Characteristics for Spring, Fish, Upper Prior, and Lower Prior Lakes
- 2016 Upper and Lower Prior Lake Curlyleaf Pondweed Assessment
- 2016 Upper and Lower Prior Lake Aquatic Plant Evaluation
- 2015 PLSLWD Aquatic Plant Summary
- 2015 Upper and Lower Prior Lake Curlyleaf Pondweed Assessment and Aquatic Plant Survey
- 2014 Upper and Lower Prior Lake Curlyleaf Pondweed Assessment
- 2013 Upper and Lower Prior Lake Curlyleaf Pondweed Assessment
- 2012 Upper and Lower Prior Lake Curlyleaf Pondweed Assessment
- 2011 Upper and Lower Prior Lake Curlyleaf Pondweed Assessment
- 2010 Upper and Lower Prior Lake Curlyleaf Pondweed Assessment