FAQ: Water Levels on Lake Minnetonka and Minnehaha Creek

Tiffany adjusting the Gray's Bay Dam

What is the Lake Minnetonka Water Level and Flow of Minnehaha Creek?

The most current Lake Levels are posted here. The current level and flow of Minnehaha Creek is available here.

When is Minnehaha Creek Good for Paddling?

The creek is best for paddling when the creek flow is between 75 cubic feet per second (cfs) and 150 cfs. Please note that creek flow is different from dam discharge, as water runs into the creek from different sources like runoff, storm sewers, wetlands, etc throughout the length of the creek which impacts the flow.

To view creek flows, please visit this USGS page which shows readings from the flow gauge at Hiawatha Ave in Minneapolis. Please note, USGS uses the term "discharge" on their site to describe creek flows.

What does Ordinary High Water (OHW) Stand For and What is the OHW of Lake Minnetonka?

 The Minnesota Department of Natural Resources provides a techinical definition of OHWThe OHW of Lake Minnetonka 929.40.

Where can I View Past Lake Levels?

You can view lake levels from 1906 to 2012 either as an Excel Spreadsheet (lake levels) or a graph (lake levels)

How is the Gray's Bay Dam Operated?

  • Gray's Bay Dam Discharge Zones and Allowalbe Discharge Rates GraphThe dam was built in 1979 to help regulate flooding on Lake Minnetonka and Minnehaha Creek.
  • The operating plan was developed by MCWD and approved by local municipalities and the DNR.
  • The dam is operated by the District in accordance with the limitations set forth in the Headwaters Control Structure Management Policy and Operating Procedures and Minnesota DNR Permit #76-6240.
  • Read the Headwaters Control Structure Management Policy and Operating Procedures

What are the Management Goals of the Dam? 

  1. To reduce downstream flooding by controlling the discharge to Minnehaha Creek to a rate not exceeding the maximum carrying capacity of the creek whenever the Lake Minnetonka water level is within the physical limits of control.
  2. To reduce flooding on the lake by stabilizing lake levels between the elevation of the low point on the previous fixed weir (928.6) and the Ordinary High Water level (OHW), elevation 929.4.
  3. To reduce flooding, on the lake and downstream, by temporarily increasing or decreasing discharge rates to accommodate predictable and large volumes of runoff into Lake Minnetonka or downstream prior to the time such runoff occurs.
  4. To provide discharges, during and/or following dry periods, comparable to discharges that occurred historically under similar lake level conditions such that the detrimental effects of creek flow stagnation are not aggravated as a result of operating procedures.
  5. To enhance recreation, wildlife and aquatic life survival, and aesthetics, when feasible and consistent with the Management Policy, by augmentation of creek flow beyond the time discharges from Lake Minnetonka have historically ceased.
  6. To improve or maintain conditions on the lake and the creek, over those which existed prior to construction of the Headwaters Control Structure.

When is the Dam Closed?

Based on the Operating Procedures there shall be no discharge whenever the Lake Minnetonka level elevation is below 928.60, which was the lowest elevation on the previous fixed crest weir. The dam is also closed during the during winter season.

Other Items of Interest: