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Recommendations

Significant Findings

Exceedences of ocean water quality standards occurred from 3 hours up to 48 hours and the indicator organisms behaved differently.

Nitrate and Salinity served as useful tracers for following the Slough discharged waters in the ocean

Slough water impacts were observed on both sides of the mouth indicating physical conditions (Wind, waves, longshore currents) were relatively benign. However, if a large north-swell or south-swell was present during our study or other physical conditions were more pronounced this might affect the distribution of bacteria in favor of one direction of the coast or the other.

Physical measurement supported conceptual understanding of bacterial abundances. It appears from our study, that the flow discharge during the first 0 to 24 hours was greater than the tidal exchange indicating a net positive flow out of the slough for the majority of this time and the highest bacteria densities in the ocean. By 24 hours or so, the discharge had significantly decreased and the tidal exchange became more dominant, resulting in a decrease in the abundances of bacteria residing in the Slough impeded by incoming high tide.

Recommendations

Beach advisory zone: from 200 yards upcoast to 400 yards down coast for a minimum of 48 hours.

24 hours after breach event, sample at -50, mouth, and +50 yards locations and interpret the results to determine if samples meet water quality standards. If they don't, leave the advisory sign on the beach.

Repeat this process every 24 hours until water quality standards are met.

A downcoast 400-yard spatial boundary was selected due to previous studies, and is consistent with most County Agency policies throughout Southern California for beach advisory zones. The study did not necessarily place into question the use of this arbitrary boundary, although our results showed that exceedences may occur beyond that boundary. It is difficult to make a decisive decision on this point since the analyses hinted that the true boundary of harmful contamination fell near the 400-yard; whether this was within or beyond the arbitrary boundary remains questionable.

This web site focuses on the water quality issue of our study; however, the research also includes an analysis of the current permitting process requirements prior to perform a breach event

If you are interested in reading more about our study, our group project thesis is filled with the University of California, Santa Barbara library and is referenced as followed: