Corte Madera Creek Repair, Mill Valley (Notification of Lake or Streambed Alteration, No. EPIMS-MAN-58752-R3)

The California Department of Fish and Wildlife has executed Lake and Streambed Alteration Agreement EPIMS Notification No. EPIMS-MAN-58752-R3 pursuant to Section 1602 of the Fish and Game Code to Evan Cross, Architect LEED AP. The Project is limited to repairs to a previously naturalized section of an existing three-sided concrete stream channel to prevent undermining the channel walls. Similar previous repairs at the Project location were permitted under Streambed Alternation Agreement NO. 1600-2011-0274-R3, which is expired. Material from the previous repairs has since mobilized and is no longer present at the Project location. To address the undermining during high flows, the Project will create a meander with natural materials to slow flows, as previously done. To achieve this and ensure the material will not mobilize again, the Project will place larger materials including small boulders (24-inch diameter), large rock (12-inch diameter), gravel mixture, and sand within the channel (Exhibit A), totaling in 20.5 cubic yards of materials placed. The placement of these materials will also provide a more natural habitat for aquatic species. All work will be done by hand. Prior to any work within the stream channel, the work area will be dewatered via a water diversion system. The Project will result in 40 linear feet (400 square feet) of temporary impacts to stream habitat associated with the water diversion system and placement of natural materials. The Project will not result in any permanent impacts to stream habitat.