Study finds smart fixes for refilling aquifers

U.S. Congresswoman

In Southern California over the past 75 years, we've developed an elaborate flood control system that has turned many local creeks and rivers into concrete channels. That's allowed the rain from heavy storms to be moved quickly out to sea, thereby minimizing the risk of floods. It's also allowed for more building and development close to the formerly wild waterways.

Paving and developing our urban areas has also reduced the natural ability of the ground, creeks, and wetlands that once existed to absorb rainwater and bio-degrade contaminants (both human-made and naturally caused) that can pollute our nearby ocean and beaches. The rainwater-and trash and contaminants it carries-now flows largely unhindered to the sea. Paving over our urban areas has also reduced ability of the ground to absorb rain and recharge underground water supplies. That requires us to import more drinking water from the Colorado River and Northern California, which does not come cheaply nor without the risk of long-term supply problems.

Certainly, with over 15 million people in Southern California today, we can't return to the days of hundreds of meandering streams that can become raging rivers in urban areas in heavy rains. But we can learn the ecological benefits of what once existed in our natural watersheds, and see if re-creating some of those natural features in our urban environment can be beneficial.

There's an intriguing study under way that's exploring many of these issues. It's called the Water Augmentation Study. It's being carried out locally by the Los Angeles and San Gabriel Rivers Watershed Council, in conjunction with the U.S. Bureau of Reclamation. Project partners include TreePeople, the Metropolitan Water District, and the L.A. County Department of Public Works.

Fortunately, the greater Los Angeles area is home to several innovative experiments in urban design related to reducing storm water runoff. A home and yard in South Los Angeles have been retrofitted to create virtually no storm water runoff and to instead retain nearly all rain falling on the site for irrigation and natural absorption in the soil. A rooftop and parking lot at a commercial building in Santa Monica were designed so that rainwater doesn't flow to a storm drain (as is usual), but instead to landscaping on the property where it can be naturally absorbed in the soil. During heavy rain, excess water can still flow to storm drains, but not before the 'first flush' of the most contaminated storm water is naturally filtered by the landscaping. These innovative designs hold the promises of reducing contaminated storm water flow to our ocean and increasing the natural percolation of rainwater back down to our underground aquifers.

The Water Augmentation Study is analyzing these innovative designs to see if those promises will hold true. A key question will be whether contaminants in water flowing from parking lots, rooftops, and other parts of our urban landscape are being successfully filtered out and bio-degraded by plants and soil prior to the water reaching underground aquifers. Obviously, we don't want to contaminate our drinking water supplies. The Water Augmentation Study's initial findings are very positive. The test water reaching aquifers is not harming the quality of the water, and is in many cases cleaner than the water in the aquifers! It turns out that plants and soil have a remarkable ability to filter out and bio-grade bacteria and other forms of contaminants found in typical storm water runoff.

The study is finalizing its test results. The next phase calls for plans to be drafted for how different types of retrofitting in neighborhoods can yield positive results for storm water reduction, groundwater augmentation, and natural beautification.

I've been so intrigued with the study that I've led an effort in Congress to secure federal funding for it. We've succeeded in getting funding approved to keep the project going over the past two years, and we're working hard to get funding through Congress this year to keep it going until the completion of the final phase.

I've also been very pleased to 'augment' the Water Augmentation Study by securing funds in the recent federal SAFE-TEA-LU transportation bill (HR 3) so that several Southern California cities can add innovative storm water reduction features to local infrastructure projects. For example, I secured federal funds for the city of Whittier to create a bio-swale along a mile-long stretch of Whittier Blvd. It's expected to be one of the largest demonstrations of a bio-swale in California. Street runoff will enter the bio-swale from openings made in the curb along the roadway. The runoff will be naturally filtered and absorbed by plants and soil in the swale instead of directly entering storm drains and flowing to the San Gabriel River and the nearby ocean as in the past. An aesthetically pleasing, creek-like setting will be created within the middle of a suburban Southern California community, similar to creeks that might have existed 100 years ago. But, for modern safety, storm drain openings will still exist to take high flows of rain away during storms.

Hopefully, in the years ahead, Southern California will create less pollution for our ocean and beaches, will be become a bit more water self-sufficient, and even look more natural in the process, thanks to promising urban design techniques that rely on natural environmental processes. To learn more about the Water Augmentation Study, visit www.lasgrwc.org. To learn more about innovative and natural storm water reduction projects, visit my Congressional website at www.lindasanchez.house.gov.

Congresswoman Linda Sánchez represents the 39th District in southeast Los Angeles County. She can be reached at 562-429-8499.