3.2 Water Quantity

  1. Drainage is conveyed through the subwatershed through several streams and channels to lakes and wetlands, which outlet to or an in-line with Six Mile Creek.  The Upper Watershed Stream Assessment identified eight erosion locations on the creek.  The HHPLS predicted that development between 2000 and 2020 would increase average flow in the creek.
  2. The HHPLS identified a number of locations that are predicted to overtop during the 100 year event, as well as others with a minimal amount of freeboard.  Some residences on Lake Zumbra have less than desirable freeboard over the 100-year elevation of the lake, which may increase slightly due to development.  More detail is available in the HHPLS. 
  3. Development is predicted to increase the volume of stormwater runoff from the subwatershed, increasing nutrient and TSS loads conveyed downstream.
  4. The HHPLS identified several locations where for both existing and future conditions higher velocities than desired may result in erosive velocities at outlets or culverts.   These include several road culverts and the Turbid and Lunsten Lake outlets.  Erosion control or energy dissipation measures may be required in those locations.
  5. Several landlocked basins are present in the subwatershed.  Within these landlocked basins, any future development or redevelopment should minimize creation of new stormwater volumes.  Outletting will generally be discouraged unless there is a demonstrated threat to property structures or public safety.