Restoration of San Dieguito Lagoon
Coastal Environments has been involved in the restoration of San Dieguito Lagoon since 1992 for Southern California Edison (SCE). SCE has the general objectives of preserving, enhancing, and enlarging the wetland habitat within the lagoon. To complete these goals our efforts included:
- Determination of the physical aspects within the lagoon, which included monitoring of sediment levels and water quality within the lagoon and lagoon inlet channel
- Determination of the baseline conditions within the lagoon
- Developing project alternatives for the ongoing restoration and maintenance of lagoon resources
- Project permitting
- Determining effects on local beaches adjacent to the lagoon inlet channel.
Based on the measurements and studies conducted within the lagoon from 1991-present a restoration plan was developed to complete the restoration of the lagoon and restore the tidal prism to 135-150% of the existing tidal prism. This required that the lagoon inlet be kept open most of the time.
The dynamics of small, shallow lagoon inlets are highly complex. Lagoon hydrodynamic behavior depends on channel bottom topography, which changes rapidly in response to river floods, tides, and wave-driven sand transport. A comparison between the existing lagoon and the restored lagoon was made, including tidal prism and influx volume of sediments. The restored lagoon will require periodic inlet maintenance to insure continued tidal flushing.
A dredging plan was prepared. The plan includes periodic inlet maintenance dredging, a sediment disposal location, and a monitoring plan, which includes topographical surveys, water level, and water-quality measurements.
Southern California Edison
2244 Walnut Grove
Rosemead, CA 91770