Sediment budget for Monterey Bay.

Abstract

A sediment budget analysis based on the principle of mass conservation is performed for Monterey Bay. The various littoral processes in the Bay are evaluated quantitatively. The results indicate that about 2.1 million cubic yards of sand are deposited annually into the Bay, which is treated as a quasi-closed system. Deposition from cliff erosion, computed from the cliffs profile changes, amounted to 5.6 million cubic yards, and accounted for 27% of the total deposit. River discharges were extrapolated using a power law formula; the total yield was 1.4 million cubic yards, representing 54% of the entire sediment deposition. The potential longshore drift was evaluated using a 18 years spectral wave climatology; its contribution was 4.09 million cubic yards which amounts to 19%. Sediment losses accrued from submarine canyon deposition, sand mining operations, offshore deposition by rip currents and eolian sediment transport to the dunes; these losses amounted to 2.34 million cubic yards and were all estimates taken from previous studies. The budget deficit signifies an erosion trend along the Bay. The effects of sand mining to coastal erosion are discussed. Recommendations needed to refine the budget analysis and to establish a correlation between the budget deficit and shoreline erosion are presented for further research