Wetlands Guide

Wetlands are natural areas that develop as a result of the interaction of land and water. Wetlands support an abundant variety of wildlife and often form the most productive habitats among the world's ecosystems. Numerous animal species depend on wetlands for critical parts of their life cycles. In addition to providing habitat, wetlands help to reduce the effects of pollution, control flood waters, contain erosion, enhance groundwater recharge, and have high aesthetic and recreational values.

Despite their numerous benefits to the environment, the majority of wetlands in California have already been lost. This loss of habitat has also resulted in a corresponding loss of wildlife species, and an increase in the number of plants and animals classified as threatened or endangered. Areas that historically have been immune to flooding now experience water damage on a regular basis because upstream wetlands that formerly acted as a reservoir for flood waters have been filled. Stream and river banks, stripped of their protective barrier of wetland vegetation, now erode away, exposing more land to further damage.


The San Luis Obispo County Coastal Zone Land Use Ordinance contains the following definitions:

Lands that may be covered periodically or permanently by shallow water, including saltwater marshes, freshwater marshes, open or closed brackish water marshes, swamps, mudflats, and fens.
The normal channel or limits of an intermittent or perennial stream. or other body of water, during non-flood conditions.
Riparian Vegetation
An association of plant species growing adjacent to freshwater watercourses, including perennial and intermittent streams, lakes and other bodies of freshwater.


Because wetlands are so important to the community, several agencies are charged with regulating activities that could affect them.

In California, any alteration of wetlands generally requires review and approval from the State Department of Fish and Game and the U.S. Army Corps of Engineers. The Army Corps also consults with other federal agencies on wetland permits, including the U.S. Fish and Wildlife Service, the Environmental Protection Agency, and the National Marine Fisheries Service. In the Coastal Zone, additional special standards governing development in and around wetlands are contained in the California Coastal Act, which is administered by the California Coastal Commission, the County, and local cities that lie in the Coastal Zone.

The County of San Luis Obispo has incorporated the state and federal approaches to wetlands into the Land Use Ordinances for both the inland and coastal portions of the County. If your project involves wetlands, we will work with you to identify the requirements of these other agencies so that you can design your project to meet all of the various regulatory requirements.

Common wetland plants

  • Cordgrass
  • Pickleweed
  • Cattails
  • Willows
  • Rushes
  • Mugwort
  • Sedges
  • Box elder
  • Wild blackberry
  • Mexican elderberry
  • Alder
  • Mule fat
  • Wax myrtle
  • Cottonwood
  • Sycamore