SCH Number 2020040181

Project Info

Title

City of Del Mar Sand Compatibility and Opportunistic Use Program

Description

Beaches in north San Diego County have been narrowing over the last 60 to 80 years due to reductions in natural sand supply from upcoast and upstream. The City is working to restore the sediment supply to its coast by direct sand placement through the implementation of a SCOUP. The SCOUP outlines a plan to capitalize on opportunities to obtain beach-quality sand from construction, development, maintenance, or dredging projects in the region for placement as beach nourishment within the City. The SCOUP presents a streamlined program of sand placement at specified locations in the City to allow quick and efficient placement of material as it becomes available. The program identifies a maximum envelope within which sand may be placed as it becomes available through the implementation of individual projects, usually of relatively small volume. The envelope would extend from the Del Mar bluffs in the north (north of the San Dieguito River inlet) to Powerhouse Park (north of 15th Street towards the center of Del Mar’s shoreline). The proposed envelope extends 5,750 feet; however, individual opportunistic placement projects would take place in smaller footprints within the proposed overall SCOUP envelope. Sand volumes available for nourishment at any given time may range from 500 cy to the maximum placement of 180,000 cy/5 years. The beach fill design for the SCOUP includes two different nourishment approaches: beach berm and surf zone placement. Sand material is anticipated to be from local or nearby contributions, such as from upland construction, development, or dredging/excavation projects (e.g., wetland restoration, or river inlet/detention basin maintenance). The San Dieguito River is the most likely sand source for beach nourishment in Del Mar. The City would require sampling and analysis of the material under a Sampling and Analysis Plan & Report to be approved by the U.S. Army Corps of Engineers, U.S. Environmental Protection Agency, and Regional Water Quality Control Board prior to placement on the beach. Sand could be delivered either by truck or pipeline, depending on the material source. Nourishment sites would be monitored over time so that the program may be modified, with agency consent, for maximum environmental sensitivity while also maximizing nourishment of the beach and littoral zone. Monitoring metrics would include beach profiles, surf conditions, turbidity, grunion, and trash/debris removal. This MND addresses impacts associated with placement of material within the beach nourishment envelope, as well as extraction of material from maintenance activities, such as detention/sedimentation basins, dams, or the San Dieguito River inlet channel.

2 documents in project