4.13 Floodplains

Goal 13 - Floodplains

Reduce the severity and frequency of flooding and high water by preserving and increasing the existing water storage capacity below 100-year flood elevations on all waterbodies within MCWD.

Discussion

The primary strategy in the management of stormwater and prevention of flooding in the Lake Minnetonka subwatershed is the preservation of the stormwater storage.  Key areas identified in this plan for conservation include wetlands that provide floodplain storage and areas that provide channel and stream floodplain and riparian zones.

Desired Outcomes: No net loss of floodplain storage.

Metrics:   Acres net floodplain fill.

Goal 13.1 - Lake Minnetonka

Preserve the existing water storage capacity below the 100-year event elevation.

Actions

  1. Minimize development below the 100-year event elevation.
  2. No net loss of the large wetland complexes that provide substantial stormwater storage throughout this subwatershed.
  3. Encourage the development and maintenance of depressional storage within the subwatershed.
    1. Promote the acceptability of minor flooding within the floodplain.

Goal 13.2 - Lake Minnetonka

Utilize District hydrologic and hydraulic data to identify potential public infrastructure high water impacts.

Actions

  1. The HHPLS noted that the 100-year water level was expected to overtop a number of public roads and private driveways.  Local plans should identify these observed or potential locations and assess whether the risk of occasional flooding is acceptable or should be addressed.  Assist LGUS in determining specific impacts and potential improvements.