Demonstrating that one never knows where danger lurks, an unprecedented mosquito infestation suddenly erupted across areas within a few miles of the Palo Alto Baylands early last week, signaling a significant problem with the flood-control equipment that protects us against flooding.
The culprit is a major breach in an important flood-control gate that regulates the amount of water in the flood basin. The leak has caused the flooding of more than 200 acres of marshland and has created the conditions for millions of decade-old mosquito eggs to suddenly hatch and begin a breeding cycle, including some nasty bites.
The agency responsible for the flood gate, the Santa Clara Valley Water District, acknowledges that it has known about a smaller leak since last November and said it "had plans to budget an investigation for a repair project for the coming budget year," according to a statement on its website.
But about two weeks ago the leak expanded significantly, triggering not only the mosquito infestation but all-out efforts by another agency, the Santa Clara County Vector Control District, to bring the problem under control. Helicopters sprayed the Baylands Thursday morning and another spraying is anticipated next week, which is hoped will be adequate if repair plans remain on track.
The annoyance of the nasty mosquitoes aside, the problem with the flood-control tidal gate cannot be taken lightly. The water district sent divers into the water last fall to investigate the leak and determined that a basketball-sized hole had developed under the flood gates, allowing tidal water into the flood basin when the gates were closed.
At that time, the district staff concluded the leak was harmless and dangers of a larger breach were small enough to simply monitor the problem and plan for a later fix.
Fortunately, last winter was mild and didn't bring any flood-threatening run-off conditions requiring use of the flood basin. But the proper functioning of this tidal gate is essential to providing an outlet for water flowing from Barron, Adobe and Matadero creeks during high tides and flood-danger conditions.
With the larger leak now posing a bigger problem, the Santa Clara Valley Water District is moving forward to obtain the emergency permits and approvals to do the repairs that they should have undertaken last November.
The current plan, assuming approvals from numerous state and federal agencies, calls for closing the leak under the flood gate with a temporary patch in early September, which should end the immediate crisis.
Aside from the error in not getting this problem fixed before it got worse, neither the water district nor the vector control district met their responsibility for good public communications. No public notifications were made by the water district about the initial leak and both agencies failed to take initiative to alert the public to the larger breach. The situation became public when a resident posted on Palo Alto Online's Town Square forum the response she had received after emailing the vector control district to complain about the mosquitoes. That is not an acceptable public information strategy.