The month of October surprised us with record-breaking rainfall in our region– almost double of what is typical for this time of year.
While much needed for our parched state, sudden and frequent rains can overwhelm our local waterways and cause flooding. But thanks to the flood fighting crews of the Santa Clara Valley Water District, our county’s streams and creeks were in good shape to receive last month’s storm waters.
Every year as early as June, crews gear up for the Stream Maintenance Program, one of the water district’s prime flood protection efforts. Through the summer heat until early fall (when some creeks are dry), maintenance crews toil in the sun to improve conditions on channels by strengthening levees and removing vegetation and sediment, which can impede the flow of water. The program also improves natural conditions for wildlife by maintaining creekside vegetation, preserving trees and removing trash from our waterways.
Vegetation can play opposing roles in stream maintenance; it can either increase the risk of flooding or reduce it. Vegetation in creek beds can block the flow of water, but vegetation along creek banks can prevent erosion.
As part of the program’s goal to improve natural conditions, the water district repairs eroded creek banks with the use of natural materials such as logs or boulders. Logs are used on sites where native vegetation can grow and stabilize the bank. On sites where vegetation cannot grow, or the banks are too steep, boulders help reinforce bank slopes and resist powerful stream flows that can occur during the storm season.
The 2016 Stream Maintenance Program achieved record-setting success by removing almost 85,000 cubic yards of sediment, or over 10,000 truckloads. That’s three times the average quantity in a normal year! Crews removed sediment from 20 sites along 12 streams throughout the county. They also repaired a total of 540 lineal feet of creek banks, and reinforced almost 1.3 miles of banks. Through an agreement with the U.S. Fish and Wildlife service, almost two-thirds of the sediment was placed in a salt pond to enhance the habitat of salt marshes in the South Bay refuge wetlands.
This year’s great success came as a result of timely permit approvals that allowed the program to start promptly in June. Every year the water district has to obtain approvals from regulatory agencies such as the California Department of Fish and Wildlife. The permit approval process can be delayed depending on the number of projects needing permits and the regulatory agencies’ pending applications.
Despite the operating schedule of the Stream Maintenance Program, water district strives to maintain streams year round. You can also help by reporting blockages in creeks at 408-630-2378 or through the district’s Access Valley Water customer service portal on www.valleywater.org.