- DNR Lake Number: 70002600
- Surface Area: 956 acres
- Average Depth: 13 feet
- Maximum Depth: 56 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: 18,904 acres
- Impairment Status: Impaired for mercury** and biota***
- Connectivity to other waterbodies: Water flows from Upper Prior into Lower Prior. Water leaves Lower Prior through the outlet structure and travels through the Prior Lake Outlet Channel (PLOC) to the Minnesota River.
- Public Boat Access: Sand Point (off Crest Avenue on north side of lake)
- Bridge Clearance: The elevation at the bottom of Wagon Bridge (Highway 21 bridge) is approximately 911.5′. Subtract the current lake elevation from 911.5′ to get the approximate clearance.
*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.
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.
Estimated flow through the Prior Lake outlet structure based on past measurements of lake level and discharge. Note that the data is only valid for lake elevations between 902.5 and 903.75 and when the low-flow gate is closed. Use this table to estimate flow when low-flow gate is open. Stream discharge is calculated in cubic feet per second (cfs).
Sensor is located in a well at the outlet structure roughly 3 feet into the lake sediment, so temperatures will not reflect surface conditions exactly.
Click HERE to view a larger version with text that is easier to read.
The following graphs represent the annual averages between June 1 and September 30.
- Lower Prior Lake Protection Projects
- Sand Point Beach Park Project (2018)
- Fish Point Park Water Quality Improvement Project (2015-17)
- Indian Ridge Bio-Infiltration basin (2016)
- Fairlawn Shores Bio-Infiltration basin (2017)
- Watzl’s Beach Shoreline Restoration (2015)
- Lower Prior Diagnostic Study (2013)
Reports and Studies
- Water Quality Report Card (2019-2021)
- Water Quality Report Card (2017-2019)
- Water Quality Report Card (2014-2016)
- Article: Prior Lake Elevation Analysis
- Prior Lake Historic Elevations Graph 1970-2015
- 1993 Diagnostic & Feasibility Study of Spring and Prior Lakes
Lake Vegetation Reports
- 2022 Upper and Lower Prior Lake Curlyleaf Pondweed Assessment and Aquatic Plant Survey
- 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 Assessment
- 2018 Upper and Lower Prior Curlyleaf Pondweed and Summer Aquatic Plant Survey
- 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 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