Agency fleshes out flood-control plan
LIVERMORE-AMADOR VALLEY: $727 million blueprint for flood control to enhance wildlife habitat and water quality

By Bonita Brewer
CONTRA COSTA TIMES
Tuesday, March 28, 2006

Back in the 1960s, experts thought the best way to prevent floods in the Livermore-Amador Valley was to send storm water out to the Bay -- as quickly as possible.

But that required big, wide and straight flood-control channels -- frowned upon these days by regulatory agencies. The channels are the opposite of what is considered good habitat for fish and other critters, and not exactly what makes trails along arroyos and other waterways entertaining for hikers.

Now, after eight years in the making, the valley's flood-control agency has released a $727 million stream management plan aimed at preventing floods while at the same time enhancing water quality, wildlife habitat and recreational/educational opportunities.

Rather than shoot storm water straight out of the valley, the new plan calls for diverting some to a series of gravel pits between Livermore and Pleasanton that, as mining operations are completed, are being turned into a "chain of lakes."

The stored water would be released downstream only after storms pass through the area -- meaning arroyos not yet turned into channels can be kept in a more natural state.

"The benefit is that not channelizing the streams provides an opportunity for habitat enhancement and preservation, and for natural-looking arroyos," said Zone 7 Water Agency general manager Dale Myers.

The plan identifies 45 projects on more than 80 miles of streams and channels to be done through 2035 -- providing not only flood control, but other benefits as well. Ten projects would remove or modify fish-passage barriers in Arroyo Mocho, Arroyo del Valle and Arroyo de la Laguna. Others would restore natural stream flows, replace plants with native types, stabilize stream banks, create low-flow channels, create wetlands and other habitat for sensitive species and install educational kiosks.

Meanwhile, sediment coming down from the hills during storms, which can severely plug up the arroyos, would be routinely removed to expand creek flow capacity and improve water quality.

The big question is how to pay for it all.

New flood-control projects are paid for with development fees, based on the idea that new pavement adds to overall storm runoff. Although those fees have quadrupled over the past five years, they will raise only a part of what's needed for the $479 million flood-control portion of the proposed program.

Because some existing developed areas lack adequate flood protection, and because of the overall $727 million program's other benefits, some cost sharing is needed, Myers said. He cited the possibility of seeking state and federal grants, but also a voter-approved bond measure.

"There are areas of the valley right now that do not have 100-year flood protection, and to provide that should not be the responsibility of future development," Myers said.

The 100-year flood plain is defined as an area that, at least statistically, would be expected to flood once in 100 years. Small developed areas of the valley are in the flood plain, including some near Interstate 580 and Hacienda Drive, some along Altamont Creek in Springtown, some along Alamo Creek in Dublin, near the Livermore Municipal Airport in the vicinity of Kitty Hawk Road, and on the west side of Las Positas Golf Course.

"To some degree, there is some community responsibility, because every inch of ground contributes to flooding, and because ... if any part of the valley is subject to flooding, there are potential impacts to the local economy," Myers said.

Flooding from Arroyo Mocho closed a stretch of Stanley Boulevard between Livermore and Pleasanton for several days during El Nino's fury in 1998 and played havoc with commuter traffic. That same winter, flood-control channels themselves were damaged and raging waters in Arroyo de la Laguna tore out about 20 feet from the back yard of a Sunol home and some property behind Sunol Glen School.

In 1983, streets were flooded in Pleasanton's Valley Trails subdivision because of a drainage bottleneck in Arroyo de la Laguna. Luckily, water didn't get into homes.

The draft plan and related environmental impact report are available online at www.zone7water.com. A public workshop will be held in Livermore from 3:30 to 7 p.m. April 26 at Zone 7 headquarters, 100 North Canyons Parkway.

Myers said the plan could be done in phases. This summer, the agency plans to work with community groups to decide on the highest priority projects, a timetable and financing plan.