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April 17 Rainfall Summary and Water Levels Update

Rainfall totals in the watershed map(Updated Friday, April 19)

Rainfall totals across the Minnehaha Creek watershed were approximately 1-inch. The map below shows rainfall totals from the Hennepin West Mesonet weather stations across the watershed.

2019 Spring Flood Damage Assessment

Significant winter snowpack (11th snowiest season on record), deep frost, increased soil moisture, quick spring thaw, and recent snow and rain have caused high water levels across the state of Minnesota. Currently 66 of the 87 counties across Minnesota are impacted by flooding, including Carver and Hennepin. Due to this flooding, yesterday Governor Walz sent a letter to President Trump indicating that Minnesota intends to seek a disaster declaration for the recent storms and spring flooding. Due to this situation, Governor Walz has signed Emergency Executive Order 19-30, which declared a peacetime emergency in 64 counties and 3 tribal nations. Because this declaration included Carver & Hennepin counties, both of those counties need to start assessing and documenting damages.

What does this mean for you as a homeowner?

If your home experienced flood damage this spring please contact your city and copy the county emergency manager to notify them:

Hennepin County Emergency Management: emergency.management@hennepin.us
Carver County Emergency Management: emergencymanagement@co.carver.mn.us

Lake Minnetonka water level graphLake Minnetonka and Gray's Bay Dam

  • The April 17 rain caused Lake Minnetonka’s water level to increase approximately 1.56 inches to an elevation of 929.98 ft above sea level, which is 0.25 inches below the top (930 feet) of the 202-foot-long emergency spillway located north of the dam (noted as the red line at 930 feet on the USGS graph)
  • Today’s level on Lake Minnetonka is 929.98, which is 6.98 inches above the OHW of 929.40
  • Yesterday, MCWD staff assessed the upper watershed streams that flow into Lake Minnetonka and documented that those streams are collectively flowing at approximately 150 cubic feet per second
  • It is possible that Lake Minnetonka’s water level may continue to increase over the next few days as the upper watershed streams drain into Lake Minnetonka.
  • If Lake Minnetonka’s water level increases to 930 feet, water will flow freely over the emergency spillway (noted as “Zone 7” in the graphic below) and MCWD will not be able to control the discharge of water into Minnehaha Creek
  • The Gray’s Bay Dam was increased to 250 cfs yesterday in an effort to mitigate the inflow into Lake Minnetonka while also trying to lower the lake level and balance the maximum carrying capacity of Minnehaha Creek (noted as "Zone 1" in graphic below)

Gray's Bay Dam discharge zones graphMinnehaha Creek

  • During the storm on April 17, Minnehaha Creek peaked at approximately 396 cubic feet per second (cfs) at 6:00pm
  • Minnehaha Creek is currently flowing around 295 cfs near Hiawatha Avenue
  • High flows will continue on the creek as water levels across the watershed are high and continue to drain into Minnehaha Creek

Lake Nokomis

  • The elevation of Lake Nokomis yesterday, April 18, was 816.18 feet above sea level which is 9.36 inches above the ordinary high water level of 815.40 feet
  • This week, Minneapolis Park and Recreation Board (MPRB) staff opened the weir the morning of April 15 and closed the weir the morning of April 17, which lowered the lake almost 4.5 inches ahead of the rain
  • MPRB and MCWD staff will continue to look for opportunities to open the weir next week

Mooney Lake

  • Currently Mooney Lake’s water elevation is approximately 990.10 feet
  • The Mooney Lake emergency pump is turned on whenever the lake level reaches the elevation of 990 feet between March – September
  • MCWD in coordination with the City of Plymouth and the City of Wayzata and have collectively determined that all the necessary parameters have been met and the emergency pumps will be turn on today, April 19
  • During the pumping, MCWD will monitor downstream water bodies to see if any high water conditions exist

Looking Ahead

The seven day forecast from the National Weather Service looks relatively dry. MCWD intends to take advantage of this dry weather by discharging maximum creek capacity out of the dam.

MCWD will continue to coordinate daily with agency partners, National Weather Service, U.S. Geological Survey, and Hennepin County Emergency Management to consult and review data to help inform dam operations.

The National Weather Service provides MCWD with seven-day precipitation forecasts and a prediction for how that precipitation will affect water levels. With this information, we can proactively create storage for the forecasted precipitation. Dam discharge can then be reduced before rainstorms and that storage is used to prevent flooding on Minnehaha Creek. MCWD also uses real-time weather data provided by Hennepin West Mesonet weather stations installed on MCWD properties and real-time water level data from the U.S. Geological Survey gauges on Lake Minnetonka and Minnehaha Creek.

Tips for Property Owners

Get the latest information by visiting our website and signing up for email updates.

Review your insurance coverage. There is a 30-day waiting period before a flood insurance policy takes effect. Learn more about flood insurance. Check to see if your policy covers sanitary sewer back-ups. More information is available from the Insurance Information Institute. Other resources include:

For specific questions about local flood response, including where to find sand bags and other resources, contact your city.

Minnehaha Creek

  • Edina – Dave Goergen, Public Works Coordinator, 952-826-0312
  • Hopkins - Hopkins Public Works, 952-939-1382
  • Minneapolis - 311 or 612-673-3000
  • Minnetonka – Minnetonka Public Works, 952-988-8400 between 7am-3:30pm
  • St. Louis Park – Steve Koering, Fire Chief, 612-790-4019

Lake Minnetonka

  • Deephaven – Dana Young, City Administrator, 952-358-9936
  • Excelsior - Tim Amundsen, Public Works Superintendent, 952-653-3676
  • Greenwood - Dana Young, City Clerk, 952-358-9936
  • Orono – 952-249-4600, after hours call Dispatch at 952-258-5321
  • Wayzata – Mike Kelly, City Engineer/Director of Public Works, 952-404-5316

Water Level Resources