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Prior Lake Spring Lake Watershed District

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DNR Lake Number: 70002600

Quick Facts

Surface Area

956 acres

Ordinary High Water Level*

903.9 feet above sea level

Average Depth

13 feet

Watershed Area

18,904 acres

Maximum Depth

56 feet

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.

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.

Aquatic Invasive Species

Zebra mussel, Eurasian watermilfoil, Curlyleaf pondweed, common carp, Chinese mystery snail

High Water No-Wake Restrictions

When lake level exceeds 903.9 feet*

Impairment Status

Impaired for mercury** and biota***

View Lake Level

Maps

Prior Lake, Lower map image

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.

Lower Prior Lake historic lake levels

Water Quality

Click on each image below to view in a larger size
Lower prior lake water quality report card page 1
What is PLSLWD doing to sustain water quality

The following graphs represent the annual averages between June 1 and September 30.

Historic averages

Related Resources

Ongoing Projects

Completed Projects

Sand Point Beach Park Project

Status: Completed

The Sand Point Beach Park Pond Improvements Project improves the efficiency of stormwater treatment before it enters Prior Lake. The project includes…
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Watzl’s Beach Shoreline Restoration

Status: Completed

The shoreline area at Watzl’s beach was previously dominated by invasive plants and erosion was occurring at the shoreline. As such, the site was in…
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Indian Ridge Water Quality Improvement

Status: Completed

The project will filter out sediments and nutrients from the stormwater that runs off properties and streets in the Indian Ridge Park neighborhood…
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Fish Point Park Retrofits

Status: Completed

The Fish Point Park Retrofit project includes three elements: retrofitting an existing ditch section with in-line iron-sand filters, expanding storage…
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Prior Lake Outlet Structure Reconstruction

Status: Completed

Normal wear and tear on the outlet structure resulted in cracking to the structure and diminishing efficiency. The outlet structure was replaced in…
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*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.