Last Friday, Channel 3 began airing the city’s hearing before the local Regional Water Quality Control Board. Councilman John Sibert analogized the city’s efforts to solve the problem of polluted water in Malibu Creek to a “tool box.” He meant a series of studies and methods to arrive at a solution as opposed to the board’s Draconian demand for a public sewer system. So far, the board, like all others involved, is avoiding the issue of what to do with treatment plant effluent.
Presentations by Richard Layton of Cal State Fullerton and Bruce Douglas of Stone Environmental described their work on groundwater in the Malibu Creek floodplain, once called the Civic Center area, and preposterously, “Malibu Valley.” Layton and Douglas explained their use of the ModFlow groundwater model as it was employed in the original 2004 Stone Environmental Risk Study. ModFlow is a good model, but its results in the Stone risk study were erroneous because seawater intrusion was ignored. For example, it produced an incorrect six-month groundwater travel time. Unless Layton and Douglas modify the ModFlow tool to account for seawater intrusion, their conclusions will be unreliable.
Also mentioned by Thorsen was Legacy Park that, although lacking scientifically demonstrated justification, might result in some meaningful improvement to Malibu Creek water quality. But it might not. Still another was the possibility that the city may obtain a 2.3-acre treatment plant site that the La Paz interests now offer in return for development permits. Thorsen did not mention that the site, reported by La Paz consultants to be underlain by colluvium, which implies bedrock near the surface, actually is underlain by as much as 20 or 30 feet of bootleg fill, which would require a set of very costly tools.
Still another tool described by Thorsen was the point-of-production disinfection process of handling septic-system effluent to avoid a central plant. This process presumably allows for almost complete aerobic digestion in the effluent before disinfecting it with chlorine or UV radiation, and then spreading it to the subsurface. Thorsen said that disinfection would be required for all Malibu seaside properties on PCH from Las Flores Canyon to Marie Canyon, all those in the floodplain, and all those in Serra Retreat. He made no mention of whether, on an individual-system basis, there could be a pre-installation determination of the extent to which disinfection would significantly improve local conditions. And at $40,000 a pop, that seems highly relevant.
Don Michael