Cuesta flood basin loses some depthCuesta Park supporters got some good news last week when they heard that a huge flood basin might not be necessary to save the park's open space in the event of a 100-year flood. Instead, due to a reassessment of the area's hydrology, water experts said a large "catchment pipe" could be buried under Cuesta Drive to carry overflow from the watershed south of town.
But there was a catch. Although the new study by the Santa Clara Valley Water District found that a 4.5-acre, 22-foot-deep basin was out of the picture, a slightly smaller and shallower basin still will be needed at Cuesta to provide protection for neighborhoods around El Camino Hospital. The smaller basin would be much less intrusive on the park and also save several large trees.
The shifting needs came about when the district looked again at hydrology reports that found 100-year floods would not be as severe on Permanente Creek as originally thought. The reason: it was found that a 300-acre area previously thought to drain into Permanente Creek instead flowed into a Lehigh gravel pit. The new estimate took away 10 percent of the 100-year floodwaters that were expected to fill up the basin in Cuesta Park Annex.
All of this is not expected to change the need for the previously planned basins at McKelvey Park and Rancho San Antonio Park, but with landscaping, we expect the 11-foot basin at Cuesta Annex will be much less intrusive than the much deeper design planned before.
Some residents may find it difficult to understand why it is necessary to plan now for an event that has a one-in-100 chance of happening each year. But one need only look back at the 2008 flood in Palo Alto, which caught the city by surprise and damaged 400 homes and caused $6 million in damage. Luckily, no lives were lost. The rising waters caught Palo Alto city officials by surprise, especially when San Francisquito Creek rose 4 feet in 15 minutes, which pushed it over the top of its banks.
Similarly, the recent cataclysmic flooding on the Atlantic coast and New England states, particularly Vermont, is an example of how torrential rains can unexpectedly wreak havoc on a region that may never have seen as much precipitation in such a short period.
Voters approved bonds back in 2008 to pay for these flood protections, and later the City Council endorsed the basins for all three parks. This revision, which will make carving a basin at Cuesta less intrusive and also protect areas around the hospital, should be approved by the council when it takes up the issue next month.