Flood protection: a year-round effort

While most would associate floods with the rainy season, flood protection is at the forefront of the Santa Clara Valley Water District’s summer itinerary. That’s when our Stream Maintenance Program kicks into gear. With the assistance of our diligent engineers and crews, we strive to maintain our creeks’ to safely carry stormwater downstream without flooding neighboring communities. This initiative helps repair eroded creek banks and address elements that increase flood risks, such as vegetation or sediment buildup. As always, the water district is continually looking for ways to protect and enhance the environment we live in.

This annual process allows creeks to properly function while safely transporting water and supporting ecosystems that reside in these areas. The summer months provide an ideal opportunity to work in our creeks when they are generally dry and easier to maneuver in. From June to October, our crews seek to remove sediment buildup and overgrown vegetation, and repair eroded streambanks to help keep neighborhoods safe. The debris and sediment that accumulate in these creeks can cause creeks to overflow and spill into residential areas, potentially resulting in devastating floods. Bank protection helps stabilize creeks to prevent erosion. Our team meticulously constructs every project to help maintain sturdy infrastructure for the future. This work is deeply rooted in public safety, as are our efforts to heal our creeks.

In addition to helping our creeks remain sturdy and capable of carrying stormwater, our Stream Maintenance Program helps enhance creek ecosystems and preserve the environment. Our vegetation management efforts remove invasive plant species which threaten native habitat. We focus on removing 40 invasive species throughout district-owned streams countywide.  These plants grow aggressively, crowding out native species and impacting food availability, soil stability and water quality. All of this degrades habitat and harms wildlife. The overgrowth of these plants also increases flood risks and fire hazards. Along with removing the invasive species, our teams work on revegetation, or planting native species that will enhance habitat for wildlife, provide shade and food, and improve root and soil structure, helping stabilize banks.

For the 2018 stream maintenance season, the water district has been working toward completing dozens of projects related to bank protection, sediment removal, and in-stream habitat improvement.  Below are a few projects worth highlighting this season:

• Coyote Creek levee repairs: Crews are repairing and reinforcing an existing levee on two different segments of Coyote Creek near Highway 237 in Milpitas and San José. Burrowing rodents in the area have created a substantial number of holes and weakened the levees, posing a potential flood risk. The work started in June and is anticipated to be completed by mid-October.

  

• Ross Creek – Located in south San José, this relatively small urban stream has a history of flooding dating back to the 1980s and 1990s. This waterway that flows through a residential neighborhood and collects storm runoff from drains, has repeatedly suffered from bank erosion. This maintenance season, instead of utilizing “harder” solutions like boulders, water district teams came up with an innovative and “greener” strategy to repair the creek’s banks.  This pilot effort entailed crews sowing a native seed mix along the sloped banks that will eventually bring forth successful native vegetation and help stabilize the bank. The seed mix comes in mesh pockets filled with locally sourced compost that is wrapped in a fabric grid and anchored along the bank. Crews are regularly watering the area until the rainy season when Mother Nature will take over. The hoped-for result: a healthier, sturdier, “greener” creek.

  

• Stevens Creek – Water district teams worked to improve in-stream habitat on a stretch of Stevens Creek near McClellan Road in Cupertino. In-stream habitat improvement projects are unique to waterways where steelhead thrive. Environmental regulations limit the extent of stream maintenance work and require additional efforts to improve habitat for these endangered fish. To allow for future maintenance, the water district installed gravel, and large wood material to help spawning and survival conditions. By vastly improving current stream conditions, the water district can comply with environmental requirements when removing objects, such as large woody material or downed trees, that pose flood risks along other parts of the creek.

Stevens Creek before habitat improvement.

Stevens creek after installing gravel for habitat improvement.

With 275 miles of district-owned creeks in the county,  you can bet our crews have their hands full working to maintain our waterways and keep our creeks clean and healthy. You can help our efforts by being an extra set of eyes and ears. If you notice anything clogging a creek during a storm, call our flood hotline at (408) 630-2378. You can also report any problems with creeks in our service area to our “Access Valley Water” online customer request and information system. We will assist you or direct you to the appropriate agency having jurisdiction.