Metro LA’s Water Supply Increasingly Relying on Management of Stormwater

Tell us about programs the county has in place as part of the regional effort to use local water to replenish our underground system and to substitute for imported water.

Gary Hildebrand: The county Flood Control District chairs the Greater LA County Integrated Regional Water Management Plan, a collaborative effort that started in 2006 and includes water agencies, municipalities, and other water resource agencies. The program develops and implements projects throughout the region.

The LA Basin Plan, our collaborative study with the federal Bureau of Reclamation, is close to completion. That plan looks at the potential impacts of climate change to rainfall patterns and the quantity of stormwater in Los Angeles County. It also looks at possible improvements we could implement on our stormwater management infrastructure.

What is the nature of the evolving coordination among cities, local water agencies, businesses, etc., regarding water management? How are we progressing in the effort to increase collaboration?

Gary Hildebrand: We’ve come together through the IRWMP to look at the overall water needs of the region, and we’ve cooperatively developed projects focused on increasing the resiliency of our water supply.

The state has provided grant funding for projects developed by the organizations participating in the IRWMP. Since 2006, the Greater LA Region has received around $130 million in matching state funding for more than 70 projects.

In addition, this collaboration has given us a venue to develop closer working relationships among organizations. Much of the past concern about water supply, sanitation, and resource agencies each working in independent siloes is now gone. And there is a long-standing partnership between the Flood Control District and the City of LA on projects that increase the sustainability of local water supply and stormwater capture.

Marty, from the point of view of your leadership on water at LADWP, speak to this collaboration and its priorities going forward.

Marty Adams: A key component of the city’s water future is maximizing our stormwater capture capabilities.

We’ve worked hand-in-hand with LA County since the 1940s on capturing stormwater. But we know there’s much more water to be captured. We have a number of projects that will build local water supply, and help us reduce our reliance on imports that we’re bringing in from hundreds of miles away.

We’re interested in how all those projects plug into the broader LA County plan. We know that the actions that we take in Los Angeles have far-reaching effects when it goes south of the city border; the fact is that the LA River flows out of the City of Los Angeles down to a number of other cities. Our plans reflect the county’s overall effort, and are consistent with its vision.

The county controls 14 flood-control dams in the northern part of Los Angeles, including 150-acre Tujunga Spreading Grounds, where your agencies are working on improvements. Tell us about the synergy between the city and the county, in terms of the county’s infrastructure and the productive use of that water in the city.

Marty Adams: The county provides a tremendous service to the city. We are fortunate that catching, controlling, and conserving stormwater is part of their core mission.

The city owns and funds the Tujunga Spreading Grounds, but we asked the county to operate it for us because of their expertise. (The county owns the Pacoima Spreading Grounds.)

When the county conserves water behind their flood-control dams, they release it slowly through the spreading grounds in order to avoid any flooding downstream and to provide an opportunity to get the water back into the groundwater basin. When they spread the water out of those dams, the water itself becomes water under the City of Los Angeles.

Our partnership is extremely important to us. We support county projects financially to make them viable, because we realize we are beneficiaries of these projects. We have a true partnership, sharing both financial and operational issues—all for the goal of catching the most water we possibly can, getting it back into the San Fernando Groundwater Basin, and making it our future water supply for Los Angeles.

Marty, TPR covered the launch of LADWP’s Stormwater Capture Master Plan in June 2015. The plan proposes that a number of decentralized projects go before the LADWP Board in phases. Update us on the progress of that plan, and the parts of it that have already been suggested. 

Marty Adams: All the projects that we identified in the plan as being economically viable are in process at this point. They’re represented in our capital budget, and the recent rate proposal provided the funding for them. As a result, some projects are already being executed; others are in the design phase.

The plan focused on the “lowest-hanging fruit” projects, with the biggest return on investment for our ratepayers. Through them, we are catching more rain, proportionally, than we ever have before—even without the great El Niño rains that we’d hoped for.

For instance, we recently contributed a substantial amount of money toward a street-improvement project in the San Fernando Valley that included 29 dry wells. Those wells were in service in time to catch the last two or three rainstorms.

The great thing about the Stormwater Capture Master Plan is that it is not a document that constrains us. It actually provides a standard system with which to evaluate potential projects as new thinking and new opportunities come about.

For a number of years, TPR has tracked the Rory Shaw Wetlands Park—the crown jewel of the innovative Sun Valley Watershed Multi-Benefit Project. Gary, bring us up to date on that project.

Gary Hildebrand: The Rory Shaw Wetlands project is converting a 46-acre site—a former construction debris landfill—into a multi-purpose wetlands park facility, which will capture runoff from a more-than-1.5-square-mile area in the East San Fernando Valley. This area has had chronic localized flooding problems for many years.

This project will take care of that by collecting runoff in the watershed, running it through a system of wetlands, and then utilizing that water for groundwater recharge. The site will also get about 15 acres of new parkland.

We’ve begun preparing the site for construction, and we hope to have the project completed by 2021.

Is the Sun Valley Project a unique case, or could it be a prototype for other projects around the county?

Gary Hildebrand: The techniques we are using there can be utilized in many other projects: running water through wetlands for treatment before capturing it, providing localized flood protection, etc.

But this project came with the unique opportunity of acquiring a 46-acre piece of property. You likely will not see a similar project of this scale in the county. In many cases going forward, we’ll be looking at retrofitting existing parks—similar to another project we did in Sun Valley.

About 10 years ago, we retrofitted the playing field in Sun Valley Park with a subterranean infiltration basin. That enabled us to capture the storm runoff from a 50-acre portion of the surrounding neighborhood for groundwater recharge. 

Marty, the mayor’s mandate to conserve water applies to city parks as well as to DWP. Is there a prototype from the city that is similar to what the county is doing in the Valley?

Marty Adams: LADWP works closely with the Department of Recreation and Parks to optimize their water use by helping them reduce the amount that they need for irrigation.

At the same time, we are looking for opportunities to take advantage of the open space afforded by parks to catch drainage. In some parks, we’ve already done a few small projects—quick hits like rerouting flows and getting water to stay longer on the lawns. But we also hope to do bigger projects that could double-duty the use of parks.

For instance, parks could be recessed in order to collect stormwater in areas where infiltration to the ground can help raise the groundwater table. The Stormwater Master Plan includes an analysis of opportunities; we really think there are a lot out there, and we may see a lot of development in this area over the next year or two.

Collaborations like these can also provide validation for having and funding the park. When you have a dual purpose and a dual funding source, all of a sudden more things are possible.

How have LA’s water-management and stormwater-capture efforts been informed by other regions around the world? 

Marty Adams: The ideas behind these big programs, like Gary’s described in Pacoima and Tujunga, have been on the books for a while. We’ve been doing stormwater capture for a long time; we just haven’t been doing near enough.

But what we’ve really learned from others is that we have to leverage private property and customer cooperation. There’s just not enough land to collect enough water in public space alone.

The Australian model did a lot with cisterns. Cisterns provide an opportunity both to offset water demand and to catch water, slow it down, and get it back into the groundwater basin.

We now have a pilot program with LA County, TreePeople, and LA Sanitation for a smart-cistern setup. Stormwater would be collected in a cistern on someone’s property, and then prior to it raining, the water in the cistern would be released to soak into the ground and make that volume available to capture the next storm as well.

Gary Hildebrand: Stormwater capture for groundwater recharge has always been part of our mission. Historically, our focus has been on building the infrastructure—14 dams and 27 groundwater-recharge facilities—and I think we’ve done an effective job modernizing and expanding those facilities to maximize the amount of stormwater they can capture.

Capturing the remaining water will require a variety of strategies. In addition to continued investment in regional infrastructure, we need to explore opportunities at the lot level, to see whether distributed efforts can be used effectively and economically.

That’s where we can learn from Australia. Since they didn’t have our long history of using major stormwater infrastructure, and had to begin their efforts in existing urbanized areas, they’ve adopted technologies in a distributed manner—lot by lot—and they’ve done some amazing things with that. We’re looking at how we can best incorporate that tactic into the overall water picture here.

This issue of TPR includes an interview with Robin Gilthorpe, CEO of WaterSmart, who stresses the disadvantage to water management brought on by a lack of data on water use throughout the state. Has the dearth of data with respect to water use in California impacted your efforts to create good plans for Los Angeles? 

Marty Adams: We use WaterSmart ourselves, and have two pilots going on that enable us to provide customers their information back. That is important because when we provide customers feedback on their use, they are more able to ensure they’re not being wasteful.

When we send out our “1-percent letters”—notices to our top 1 percent of customers—people are shocked. After they get over the shock, they want to reduce their water demand. They’re looking not only at the cost impacts, but how they’re doing compared to their neighbors.

The information issue that we’re seeing in the Southland is not so much from a utility standpoint but from a customer standpoint. We are working to fill that gap.

Gary Hildebrand: In terms of increasing our local water sustainability, we have extensive data from the past one hundred years on rainfall in LA County, runoff in LA County, the areas in which we can best infiltrate water, etc. That is valuable information.

We’re using that data with our partners to identify opportunities for additional stormwater capture projects—either centralized ones like Rory Shaw Wetlands Park, or distributed ones like I mentioned. Our partnership study with LADWP looks at how these things can be best managed on residential properties.

In October 2014, Mayor Garcetti issued an executive directive to cut water imports by 50 percent by 2025. How has that changed your work, and this effort at collaboration water agencies, if at all? 

Marty Adams: Before Mayor Garcetti issued Executive Directive No. 5, efforts to reduce reliance on imported water were on a slow boat. Now, we’ve accelerated the schedule. We made what could have been two decades of projects into one decade’s worth of projects.

One thing we’ve realized is that so much of this work involves more than just DWP. Our partnerships underscore the need for stormwater collection, because the only way we’re going to get around 25 percent of our drinking water delivered locally from out of the ground, is to get 25 percent of the water back into the ground.

We are tapping into all resources to help us meet those goals, and right now, we are on track to meet them.

In 25 years of publishing The Planning Report, I’ve never seen the level of attention being paid to water as we now see from the governor, the mayor, and others. Gary, how has that affected your work at the county? 

Gary Hildebrand: The sudden increase in discussions about regional stormwater capture has brought the efforts of the Flood Control District over the last 100 years to the forefront.

Stormwater capture is not a newfangled idea; it contributes a third of the county’s overall local water supply. The fact that we’ve been doing it for some time, successfully and in partnership with others, is lending this strategy a lot of credibility and support.

As Marty said, the mayor’s action has helped accelerate a number of projects, including enhancements to the Pacoima and Tujunga spreading grounds. The drought has made everyone realize that we have a good untapped resource that we need to invest money in.