The City of Mill Valley seeks to protect, maintain, enhance and restore Mill Valley's streams and waterways and adjacent riparian habitat and wetlands; to prevent further degradation of habitat and water quality; and to limit or mitigate the impacts of development activities within the riparian areas.

Riparian areas adjacent to creeks provide shade, sediment transport, nutrient and chemical regulation, stream bank stability, input of large woody debris and organic matter, hydrologic control of floodwaters, and educational and recreational opportunities. The purpose of the creek setback is to conserve the quality and quantity of remaining riparian habitat and water resources and to provide for the recovery of Steelhead trout (On-corhynchus mykiss, listed in 2000 as a "threatened" species under the Endangered Species Act) and other anadromous fish historically found within the Mill Valley watershed.

The intent is to allow development that is compatible with the important physical, habitat, aesthetic, and recreational functions of the riparian areas within the City's watershed, while ensuring that these functions and values are protected in perpetuity.

The purpose of this section is also to implement the Open Space Policies of the Mill Valley General Plan regarding protection of the City's creeks.

No structures are permitted within 30 feet of the top bank of the following creeks within the City of Mill Valley: Warner Canyon, Corte Madera Del Presidio, Sutton Manor Creek, Cascade Creek, Old Mill Creek, Reed Creek (the "Creek Setback Area").