Important information on high water across MCWD

Water levels are expected to remain high for some time
Wednesday, July 30, 2014

Current Conditions

The wettest Twin Cities spring on record caused historically high water levels on lakes and streams across the Minnehaha Creek Watershed District. Though rainfall amounts have gone down, water is still high across the District and residents are urged to take caution around lakes and streams.

As of Wednesday, July 30, Lake Minnetonka was 930.01 feet above sea level, having receded more than a foot since reaching an all-time high of 931.11 on Monday, June 23. The lake is 6 inches lower than the pre-2014 all-time high of 930.52 set in 2002 after spending 35 consecutive days above that mark in June and July.

Paddling Minnehaha Creek: Minnehaha Creek is still considered too dangerous to paddle due to swift flows, low clearance at several bridges, and trees and other debris blocking the creek. The MCWD considers the creek safe to paddle when it is flowing between 75 and 150 cubic feet per second (CFS). As of Wednesday, July 30, the creek was at 240 CFS at McGinty Road in Minnetonka and 301 CFS at Hiawatha Avenue in Minneapolis. Learn more about paddling the creek here.

Wake Restrictions on Lake Minnetonka: The Lake Minnetonka Conservation District (LMCD) has a High Water Declaration in effect, which means no wake within 600 feet of shore and in certain bays. The LMCD lifted its emergency lake-wide wake restriction on Friday, July 25. Learn more here.

Lake Minnetonka projection: Though they are receding, water levels are expected to remain high for some time. The District’s engineer, Wenck Associates, has developed a report estimating how long it may take to lower the Lake Minnetonka level to the Ordinary High Water Level (OHW) of 929.40 given normal precipitation events. Assuming normal weather conditions for the rest of the season, the District’s engineer now estimates Lake Minnetonka would not reach the OHW elevation until mid- August. See attached graph for details.

Flood recovery

Many residents of the MCWD were impacted by the high water and flooding. Below are some resources for flooding recovery:

  • Damaged shoreline?
  • Disposing of sandbags: From the Minnesota Pollution Control Agency: "Floodwater can contaminate sandbags with bacteria and other pathogens. And used sandbags that are not properly managed can develop mold over time." Read the MPCA's list of tips for disposing of sandbags after a flood.
  • Disposing of AIS that washes ashore: The high water means more debris washing up on shore, which for some lakes and streams will include aquatic invasive species like zebra mussels or Eurasian watermilfoil. Please be careful in disposing of these harmful plants and animals to make sure you don't spread them elsewhere. Options for disposal:
    • Compost. The heat generated by the composting process kills zebra mussels and will break down milfoil and other aquatic plants
    • Take to a yard waste facility. Transporting AIS requires a permit from the Minnesota Department of Natural Resources. You can apply online.
    • Toss in the trash. Contact your garbage hauler and ask if they are permitted to transport aquatic invasive species in Minnesota
  • 2014 Minnehaha Creek Cleanup: The 2014 Minnehaha Creek Cleanup has been re-scheduled for Sunday, September 7 due to the high water, and there should be plenty of trash to pick up! RSVP today!
  • Assessing damage: 
    • The Minnesota Department of Employment and Economic Development is conducting a survey on flooding impacts to businesses. Learn more and fill out the survey online.
    • MCWD is assessing damage across the District and plans to work with communities on repairs and mitigation efforts to prevent damage from future high water events.

2014 Dam Operations

Due to the record rainfall this spring and early summer, the volume of water in the system exceeded the Gray’s Bay Dam’s capacity to manage water levels on Lake Minnetonka and Minnehaha Creek for more than two months. Water started going over the spillway north of dam when lake level went above 930 feet on May 9.With the wetland at the headwaters of Minnehaha Creek at nearly the same level as Lake Minnetonka, the best estimate of how much water is flowing into the creek is at McGinty Road, which is the first overpass downstream of the dam. 

Prior to ice out this year, the District assessed the lake level and determined there was sufficient capacity in the lake for the spring snow melt. After ice out, the lake level was approximately ½ foot below the top of the spillway and the dam was opened according to the DNR-approved operating plan.

Soon afterward a wet weather pattern ensued and staff increased the dam discharge rate to mitigate rising lake levels , in accordance with the operating plan. However, continued bouts of heavy rain throughout the months of May and June caused lake levels to continue to rise, exceeding the dam’s capacity to manage water levels, resulting in flooding on both the lake and creek. Learn more about the Gray's Bay Dam Operating plan here.

   
(Before and after: The emergency weir north of the Gray's Bay dam, from May 1 and June 20)

Beach closures

Hennepin County provides an updated map of the status of public swimming beaches.

Flood Risk Profile and Flood Insurance

The following resources provide information on assessing your flood risk and obtaining flood insurance:

Be safe around high water

In a car: Do not try to drive through a flooded roadway. As little as 2 feet of flowing water can carry away most vehicles, including SUVs and pickup trucks. Do not attempt to drive through water that comes close to halfway up your wheels, turn back. Rather, reverse carefully out of the water. Keep in mind that 80 percent of flood deaths occur when people try to drive through and become submerged.

On foot: Do not walk in or play in flooded streets. It only takes about 6 inches to knock an adult off his or her feet, and less for a child. Mucky water also can obscure sharp or other dangerous objects or sinkholes that could cause injury.

Flood water is not clean water: Flood water often contains sewage and other pollutants that can cause illness. Flooded buildings also can quickly become unhealthy places, due to contamination and mold and mildew, which can grow very rapidly. 

Read more tips from the Minnesota Department of Health.