- DNR Lake Number: 70007200
- Surface Area: 386 acres
- Average Depth: 10 feet
- Maximum Depth: 43 feet
- Bathymetry Map: View map here
- Ordinary High Water Level: 903.9 feet above sea level
- High Water No-Wake Restrictions: When lake level exceeds 903.9 feet*
- Watershed Area: 16,038 acres
- Impairment Status: Impaired for Mercury,** Biota,*** and Excess Nutrients****
- Connectivity to other waterbodies: Water flows into Upper Prior from Spring Lake through the Spring Lake channel and flows Upper Prior into Lower Prior Lake.
- Public Boat Access: Dewitt Ave (on southern end of Upper Prior)
- 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.
- Aquatic Invasive Species: Zebra mussel, Eurasian watermilfoil, curlyleaf pondweed, common carp
*No-Wake restrictions are set by the City of Prior Lake and enforced by the Scott County Sheriff. Once high water levels have subsided and remained below the no-wake level (903.9 ft) for 72 hours, no-wake restrictions will be lifted. For more details, view the full city ordinance.
**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.
All lake level data below are approximate and preliminary – NOT to be used for legal purposes. Sudden drops or spikes are often due to calibration, which are manual adjustments to correct the lake level value. Please contact the PLSLWD office for official readings.
For more information about the Outlet Structure, click here.
Occasionally, especially during cloudy weather, the level logger does not get service and the lake level does not get updated automatically on the graph below. This can last for a couple days and there is nothing we can do. If you need to know the lake level, you can check the staff gauge on the NW pillar of Wagon Bridge (Hwy 21 bridge crossing Prior Lake, across the road from Knotty Oar Marina). Just add 900 to the number that you see to get the mean sea elevation.
Historical Lake Levels
The graph below displays the average of annual lake level readings, when available. Some years only had one lake level measurement so those would not reflect the “average” and could have been taken at any time of year. Also, some years are missing from this graph because there is no known data available. The red line indicates when the weir was installed. Prior to the red line, there was no natural outlet for Prior Lake.
- Spring Lake-Upper Prior Lake TMDL Report (link to MPCA site)
- Spring Lake-Upper Prior Lake TMDL Implementation Plan (2012)
- Water Quality Report Card (2019-2021)
- Water Quality Report Card (2017-2019)
- Water Quality Report Card (2014-2016)
- Upper Prior Lake In-Lake Phosphorus Management Plan (2017)
- Upper Prior Lake Plankton Sampling Report (2020)
- Plankton form the base of lake food chains
- PLSLWD Upper Watershed Assessment (2010)
- Prior Lake Historic Elevations Graph 1970-2015
- 1993 Diagnostic & Feasibility Study of Spring and Prior Lakes
Aquatic Vegetation Reports
- 2021 Upper and Lower Prior Lake Curlyleaf Pondweed Assessment and Aquatic Plant Survey
- 2020 Upper and Lower Prior Lake Curlyleaf Pondweed and Aquatic Plant Survey Report
- 2019 Upper and Lower Prior Lake Curlyleaf Pondweed Report
- 2017 Upper and Lower Prior Lake Curlyleaf Pondweed Report
- 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
- 2008 Curlyleaf and Eurasian Watermilfoil Growth Potential based on Lake Sediment Characteristics for Spring, Fish, Upper Prior, and Lower Prior Lakes