MAILBAG - Dec. 26, 2007

Interpretation needs some clarification

Don Schulz of the Surfrider Foundation (“No warnings posted for contaminated water,” Dec. 6) offered an erroneous interpretation of results previously reported and discussed by the Bolsa Chica Conservancy at the recent Headwaters to Ocean Conference in Long Beach.

The conservancy sampled ebb and flood tides on 18 dates chosen for extreme high and low tides. We chose to sample under worst-case conditions because our primary interest was to see if there was evidence of an outward flow of contaminants from inside the new inlet. By the logic of our experiment, there was no such evidence because more of the instances of high bacterial presence occurred with the incoming waters of flood tide. This is what we reported.

Sampling under worst-case conditions makes our regimen very different from Orange County Health Department’s daily procedure. It is not surprising that the proportion of our samples that exceeded the AB411 standard was greater than theirs, since the department samples at a regular time every day, regardless of time or extent of tides. These two proportions are not comparable, although Don Schulz compared them.

What is comparable are the results drawn by the researchers who reported at the conference. Neither the Health Department nor the conservancy saw any negative impact of the newly restored wetland on the quality of surrounding waters.

BOB HOGAN

Bolsa Chica Conservancy