San Rafael, CA – As Marin County continues to suffer through one of the most extensive droughts on record, the possibility of measurable rainfall this month is heartening. Even during a drought, Marin can experience significant rainfall from an atmospheric river event that can heighten the risk of flooding and property damage, so the Marin County Department of Public Works (DPW) has been working hard to prepare.
In an ongoing effort to improve public safety, the annual storm season preparations conducted by DPW and its contracted agencies have been completed across the region, a crucial job for flood mitigation and stormwater drainage.
Preparing for storm season is a major undertaking that requires work year-round, including clearing debris from local creeks. (Archive photo)
Marin has a wide variety of microclimates and ecosystems, all of which are being impacted to different degrees by the drought. While it is anticipated that the unsaturated soils in most areas would be able to absorb an above average amount of rainfall, the key is preparing for all potential outcomes.
“We stress the importance of the public being prepared for emergencies, and we take that same approach to our own work,” said Liz Lewis, DPW’s Water Resources Manager. “Preparing for storm season is a major undertaking that we work on year-round. By the time there’s any significant rain on the horizon, we’ve generally been finished with the prep work for weeks.”
Storm season preparations, which are usually completed by fall, cover a wide range of work on creeks, levees, tide gates and pump stations. Tasked with this responsibility in parts of Marin, the Marin County Flood Control and Water Conservation District identifies issues and manages improvements in eight flood control zones across Marin. The zones do not cover the entire county and are, for the most part, concentrated in the county’s urbanized eastern corridor. The District oversees more than 37 miles of creeks and channels, 14.23 miles of levees and berms, 1.34 miles of floodwalls, 17 pump stations, eight portable pumps, and several stormwater basins.
Many areas of Marin are not within one of the flood control zones and therefore are not under the District’s supervision. The infrastructure not covered by the District includes state-maintained roadways such as Highways 37, 101 and 1, which are overseen by California Department of Transportation (Caltrans). DPW and District staff communicate regularly with Caltrans to help strategize short- and long-term solutions to ongoing flooding issues on Caltrans’ property, such as the Manzanita Park & Ride lot at the Highway 101 and Highway 1 interchange and are coordinating with Caltrans on their short- and long-term improvements for Highway 37 in eastern Novato.
Summer creek maintenance within designated flood zones is a major part of storm preparations. The District works with local agencies, such as the nonprofit Conservation Corps North Bay, and municipal public works departments to handle maintenance on 18 creeks across the eight watershed zones. Teams perform essential vegetation management along creek banks and remove obstructions such as trash and dead trees across the channel to maximize flow capacity.
Each year, the District inspects 43 pumps housed at 17 stations across Marin’s flood control zones to ensure that they are functioning at optimal efficiency. The pumps play an essential part in flood reduction for neighborhoods such as Tiburon’s Bel Aire, Strawberry Circle, Santa Venetia, lower Tamalpais Valley and Novato. The pumps transport stormwater from low-lying lands into creeks over levees facilitating natural water flow out to San Francisco and San Pablo bays.
The District coordinates with DPW’s Building Maintenance and Fleet Operations divisions to complete annual service on all pump stations, including cleaning wet wells, repairing electric motors and natural gas engines. The District performs major maintenance for each pump on a six-year cycle, which includes full extraction and cleaning of the machinery.
The District and DPW crews also inspect, maintain and repair levees as part of the overall storm prep protocol. Standard maintenance includes inspecting levees and timber reinforced berms for weak points, fortifying with supportive material and filling rodent burrows to prevent leaks. This is conducted on levees in the areas of Richardson Bay, Ross Valley, Santa Venetia and Novato.
Roadway work, handled by DPW’s Road Maintenance Division, is an important part of storm season preparedness. Annual practices require inspecting and cleaning roadside storm drains using a process called vactoring. Conducted in early fall, the process removes debris buildup and reduces the chances of clogging during storms. Compared with other areas of Marin, Tamalpais Valley, Marin City, Strawberry, and Santa Venetia require significantly more vactoring because of their low elevation and propensity for flooding.
There are hundreds of roadside drainage ditches along arterial and rural roads in unincorporated Marin, and those require attention as well. Upkeep on the ditches helps control stormwater flow and minimize roadside flooding and erosion. Hundreds of culverts, inlets and flow pipes are inspected and, if needed, cleared along all County-maintained roads.
During fall, roads crews sweep streets to keep debris out of drains and creeks. They use two large street-sweeper trucks and run routes across areas of unincorporated Marin with the densest concentration of trees along the neighborhood streets of Sleepy Hollow, Oak Manner, Loma Verde, Marinwood, Country Club, Greenbrae, Kentfield, Strawberry, Tamalpais Valley, and Marin City.
Residents are encouraged to take action on their own property prior to the rainy season to help mitigate flooding, including the clearing of dead leaves from driveway pipes, rooftop gutters, and storm drains. Dead foliage should be disposed of in compost bins, not left in street gutters to clog drainage systems. Those living in flood-prone areas should test their sump pumps and stock up on sandbags (available at most hardware stores) and learning how to properly use them prior to storms. Additionally, ReadyMarin.org provides many detailed resources, including emergency grab-and-go packing checklists, that can be helpful for residents to prepare for the unexpected.
It is important for residents to sign up for the Alert Marin notification system to be aware of emergency situations that could carry life safety implications, such as floods. The service, provided by the Marin County Sheriff’s Office, provides the public with time-sensitive alerts targeted toward specific addresses or neighborhoods. Residents who have registered should review their contact information to ensure it is up to date. Alert Marin is different from the Nixle service, which provides general public safety and/or post-disaster information.
Flood insurance is important for homeowners and renters alike, as it goes beyond what is covered under standard insurance policies. Even a few inches of water can result in thousands of dollars in repair and restoration costs. Marin County participates in the National Flood Insurance Program, which makes federally backed insurance available for all structures, and provides a range of resources to help property owners make the best decisions. Residents who seek such coverage are encouraged to contact their insurance agency but should be aware that it takes approximately 30 days to process.