I understand there is a planning discussion respecting authorizing additional housing development for Los Osos. I am not a resident of Los Osos and have no economic stake in that question, though my ranch is immediately upstream of their aquifer.
Over the past three years I have followed the issues respecting the domestic water resources of Los Osos and the efforts by the county to manage those resources. I do not have a political interest in the outcome, but am concerned that those proposing additional residential development appear unrealistic about the long-term future of the water resources there.
Los Osos relies entirely on the aquifer underlying the town for its domestic water. Since they have established a new sewer plant facility to replace the septic tank systems, which earlier served the community, that source of pollution is declining. However, that decline is accompanied by the loss of that source of fresh water, which is now moved to the sewage treatment plant and which, as I understand it, is not yet fully used to add back into the aquifer.
The county's management efforts are touted as maintaining what appears to be a thin margin of domestic water availability to the community, but in spite of the management efforts, seawater intrusion is increasing on the western edge of the aquifer. In response to questions about that, I have been told that it will not matter, as the domestic wells will simply be moved further east. Though this may be a solution for the short term (long enough to perhaps build additional residences), the laws of math and physics assure that without addition of new water resources to the aquifer, or reducing the rate of pumping, seawater will continue to intrude into the aquifer, ultimately destroying the freshwater supply.
In spite of the desire for greater property development, it does not seem wise that any seawater intrusion into that sole resource should be permitted, either in the short or long run.
There may be a practical means of increasing the limited domestic water aquifer, and that is by capturing some of the stormwater runoff that now fills Morro Bay with silt and erodes the drainage ditches to the east (one of which runs across my ranch). However, I am told by the environmentalists that "erosion is natural" and that "Morro Bay should be expected to decline due to natural siltation," and that capture of stormwater runoff is "unacceptable." In this respect I think the environmentalists have gone too far.
I do not have a horse in this race, but it seems worthwhile to study the capture of winter stormwater runoff in heavy rain years for injection into the aquifer to enhance the water resources of the community. Perhaps with success in that, seawater intrusion could be arrested, and, with experience, there could be sufficient freshwater resources to justify construction of additional residences in the community.
Short of that it seems a serious mistake to permit additional residential demand for the limited domestic water resources in Los Osos. Δ
John B. Goodrich writes from his ranch in San Luis Obispo. Send a response through the editor at email@example.com.