Local experts are asking residents to continue saving water despite a handful of El Nino storms passing through Santa Monica recently.

According to the California Irrigation Management Information System (CIMIS) weather station in Santa Monica, the city has received 4.97 inches of rain since January 1 and, while that’s valuable, it’s still about 2 inches less than the historical average.

“Any rain is welcome, but we haven’t seen an impact on groundwater levels yet,” said Gil Borboa, Santa Monica’s water resources manager. “Unfortunately, this year’s predicted El Nino rains have yet to materialize in Southern California, as opposed to the plentiful rain and snow in Northern California and the Pacific Northwest.”

Groundwater is Santa Monica’s primary source and it’s drawn from city-owned wells. Those wells produce up to 80 percent of the City’s water supply, with the remainder purchased from the Metropolitan Water District of Southern California.

Most of the wells are located outside city limits, and they all draw from a region called the Santa Monica Basin. Rainfall within the basin, including runoff from the nearby Santa Monica Mountains, provides most of the recharge for local groundwater, making the City dependent on rainfall as the primary source of potable water.

The connection between rainfall and the city’s water supply is direct, but often delayed.

“It’s not an exact science, but we expect it may take between six months to a year to see measurable impacts in groundwater levels following rainfall periods,” said Borboa. “Much depends on rainfall intensity, duration, and runoff patterns.  The layers in the groundwater basins we draw from are anywhere from 200 to 600 feet deep, so it takes some time for water to reach these strata.”

Rainfall within City borders is of little use to the city’s water system, as the vast majority washes out to sea within minutes of hitting the ground. Some is captured by the Santa Monica Urban Runoff Recycling Facility for use as recycled water, and the small amount that does seep into the ground continues to flow toward the ocean. Even if it were to remain in place, it would be unavailable to the city wells located outside of city borders.

“It’s understandable for people to think that the recent rains mean they can use a little more water. But we really can’t,”  senior sustainability analyst Kim O’Cain said.

She said the City’s cumulative water savings are on track, but the month-to-month savings haven’t hit their goals recently.

“Our residents and business have done a remarkable job saving water, and they should continue to save water even when it rains. Our community still has a 20-percent reduction target to meet each month, but the last few months we have not met that goal. While our cumulative water savings is currently at 20 percent, we can’t afford to slack off on saving water — rain or shine.”

Residents who are interested in capturing rainfall have several options. At a minimum, house gutters can be reconfigured with the possible addition of water barrels. Residents wanting a more expansive approach can redesign their property into a “rain garden” that specifically captures and absorbs rain.

“Many residents have directed the gutters into their yards to water plants, some have installed rain barrels or large cisterns that store rainwater for use on another day, and others are installing rain gardens,” said O’Cain. “Hundreds of residents received a rebate to harvest rainwater and more funding is available from the City. To see these options, the Airport Demonstration Garden has been recently remodeled to showcase a rain barrel and rain garden.”

Visit http://water.smgov.net for more information on ways to save water.

editor@www.smdp.com