Coastal Services Center

---

Restoring and Preserving Wetlands and Riparian Areas

---

Identifying the location of wetland and riparian areas is the first step in protecting these vital resources. Interferometric Synthetic Aperture Radar (IfSAR) provides a means to collect high-resolution elevation data over a large area, allowing the user to define the extent of wetland and riparian zones.

The Project: The Southern California Wetland Recovery Project

Southern California's wetlands and riparian zones are among the most diverse, productive, and densely populated habitats on the Pacific coast. These important habitats have been dramatically altered by human activities over the past 150 years, resulting in a loss of 75 percent of coastal wetlands and the threatened extinction of numerous wetland-dependent species. The Southern California Wetlands Recovery Project (WRP) is a partnership of public agencies working cooperatively to acquire, restore, and enhance coastal wetlands and watersheds between Point Conception, California, and the U.S. border with Mexico. This area includes the five coastal counties of Santa Barbara, Ventura, Los Angeles, Orange, and San Diego. There are sixteen public agencies with responsibilities for coastal wetlands and watersheds in southern California that participate in the project. The WRP is using a nonregulatory approach with an ecosystem perspective to:

• identify wetland acquisition and restoration priorities,
• prepare plans for these priority sites,
• pool funds to undertake these projects,
• implement priority plans, and
• oversee post-project maintenance and monitoring.

To better prioritize acquisition and restoration projects and evaluate long-term recovery efforts, the WRP needs a region-wide inventory of wetland and riparian physical and biological resources. A fine-scale digital elevation model (DEM), which can be used to define the extent of the wetland and riparian zones, is a fundamental part of this inventory. Using IfSAR, consistent, high-resolution elevation data can be collected over a large regional area but still be useful to individual cities and counties.

Deriving Wetland and Riparian Boundaries from the Data

Interferometric SAR (IfSAR) compares two SAR images of the same area taken from slightly different positions to generate relative height differences. This information can then be calibrated with known ground elevations to create three-dimensional digital elevation images. The digital elevation data derived from IfSAR will be used to delineate the wetland and riparian zone boundaries within the WRP area using mathematical models to determine the topographic zones associated with geomorphic features of stream reaches. Riparian zone boundaries will be mapped from the elevation, slope, and aspect information derived from the IfSAR data. The WRP scientists will be able to use this information along with ancillary data such as land cover, geographic information system data (hydrologic, geologic, and soil), and field data to map the physical and biological resources of riparian areas.

The Result

The project will have a region-wide inventory of wetland and riparian physical and biological resources to work with to make restoration and preservation decisions. The individual cities and counties involved also have access to the high-resolution DEMs, which can provide a wealth of information to planners and managers.

For More Information:

• California Coastal Conservancy Southern California Wetlands Recovery Project
• GeoSAR, a service of EarthData International

You may access and download this IfSAR data via our IfSAR Data Viewer.

Return to top