The Port District’s dredging operation occurs between November and April of each year. This has occurred each year since the harbor was first constructed in 1964. Sand, which moves downcoast through the process of littoral drift, becomes trapped in the harbor entrance channel. The dredging operation picks up the sand deposited in the entrance and places it downcoast, bypassing the east jetty, so it can continue to provide replenishment and protection downcoast of the harbor.
The dredge crew utilizes three types of disposal methodologies, including surf-line disposal. Surf-line disposal is most often utilized to replenish the beach with high quality sand or when the District’s offshore pipeline is unavailable. Disposal of dredged material in the nearshore achieves multiple objectives, which include replenishing beaches and surfing areas downcoast of the harbor with sand, protecting bluffs, roadways, and public utilities, as well as park assets on Twin Lakes State Beach and Harbor Beach. Sand is an important resource, and the dredging bypass system returns the sand into the system where it can provide a soft sand buffer, and reduce the need for hard-facing cliffs and other infrastructure in the coastal zone.
In accordance with regulatory permits issued and reviewed by various agencies, including the California Regional Water Quality Control Board, the California Coastal Commission, the Monterey Bay National Marine Sanctuary, and the US Army Corps of Engineers in consultation with the Environmental Protection Agency, the Port District performs all required physical, chemical, and biological analyses on material proposed to be dredged on an annual basis. Regulators from each agency review the sampling and analysis data and deem the sediment as suitable for aquatic disposal…simply stated, the material is clean, beach quality sand. Though the sand and seawater appear dark during disposal operations, it is not noxious sludge, which is why our beach area consistently attains A+ ratings.
In addition to the strict testing requirements, the Port District is also required to monitor Hydrogen Sulfide (H2S) emissions during all dredge operations in accordance with permit requirements set forth by the Monterey Bay Air Resources District. H2S emissions associated with the dredge operation are typically caused by organic material (kelp, seaweed, seagrasses, etc.) becoming entrained in the sand. A stationary monitoring system, including a vehicle mounted H2S monitor is positioned adjacent to the dredge monitoring tower (near 5th Avenue). Restrictions on nuisance level odor limitations remain at 1/3 of the State’s nuisance level.
If there are any questions regarding the District’s dredging operation, please contact Administrative Services Manager Holland MacLaurie at (831) 475-6161, ext. 19 or hmaclaurie@santacruzharbor.org.
