The Echo Park Lake Rehabilitation Project is a finalist in the 2015 ASCE’s Outstanding Civil Engineering Achievement (OCEA) award. Established in 1960, the OCEA Award recognizes a project that makes a significant contribution to both the civil engineering profession and society as a whole.
Echo Park Lake has been part of the history of the City of Los Angeles for more than 150 years. However, over time it had become a collection point for pollution and was impaired by algae and other contaminants like ammonia, copper, lead, polychlorinated biphenyls, eutrophic conditions, odor, and trash.
In 2006, Echo Park Lake was identified as an impaired water body by the U.S. Environmental Protection Agency (Clean Water Act Section 303) and the State of California, and it was evident that rehabilitation was essential to meet water conservation, water quality, and community standards.
To accomplish that, the Echo Park Lake project became part of a $500 million Los Angeles Water Bond Measure entitled Proposition O. One of the major goals of the project was to meet the water quality objectives established by the California Regional Water Quality Control Board.
The City of Los Angeles selected Black & Veatch to design the rehabilitation project and restore the iconic Echo Park Lake to its former glory. The $45 million project redefined the lake as a jewel for the local community while providing such functional benefits as public recreation, stormwater quality improvement, and establishment of wildlife refuge areas. Water quality was restored to the park through innovative green solutions using wetland treatment. These wetlands are designed to remove pollutants brought into the lake, thereby eliminating the need for any chemical or mechanical treatment.
ASCE News Associate Editor Doug Scott interviewed Jim Rasmus, P.E., BCEE, ENV SP, M.ASCE, Water Resources practice leader for the Western United States for Black & Veatch.
1. What is the most innovative or creative aspect of your project?
[In order to] reduce the City of Los Angeles’ reliance on potable water (in an already water scarce region), a harvesting system was put in place for this lake. The rehabilitation effort reroutes all upstream dry weather urban runoff – and portions of storm events – from nearly 800 acres of urbanized watershed through the lake. This harvesting system saves the city an average of more than 55,000 gallons per day of valuable potable water that is typically lost to evaporation.
In addition to evaporative losses, water also was lost through the soils underlying the lake. In exploring several options, our team ultimately found that a bentonite-enhanced clay liner would work well and eliminate the need for an expensive, synthetic liner. Geotechnical evaluations and bench tests showed that [the use of] clay found onsite, mixed with bentonite and compacted in a controlled manner, would be a very cost-effective option for reducing exfiltration from the lake.
Together these 2 systems, the harvesting system and the liner, contributed to savings of approximately $20 million in capital costs, and are projected to save the city approximately $150,000 annually in potable water costs.
2. What was the biggest challenge?
Echo Park Lake is significant as a venue for recreational activities and community events, such as the annual Lotus Festival. And despite its urban setting, the lake is also an important refuge for wildlife and many species of waterfowl.
Not only did this project have a major goal of improving water quality in the lake to meet standards established by the California Regional Water Quality Board, it needed to work for the public and the environment. These items together made for a complex challenge. Any water quality solution would have to not only solve the problem of improving water quality and maintaining the flood control functionality, but also maintain social and environmental objectives as a high priority.
Through a series of workshops, the public was engaged very early in the development of alternatives for the project, and continued to have a voice throughout the design. This led to widespread community support for the project. Each component of the overall solution came with careful consideration of community input and sustainability criteria.
3. Did your project have any technical issues that you had to overcome? If so, what were they and how did you overcome them?
The California Division of Safety and Dams (DSOD) protects against the loss of life and property from dam failures. A series of options were considered by the team to address DSOD requirements early in the rehabilitation efforts. The team ultimately selected an option to remove the lake from DSOD jurisdiction by developing a submerged berm that divided the lake into 2 cells – each less than the 50 acre-foot minimum volume threshold for the lake to be considered formed by a jurisdictional dam. The berm simplified the permitting process and was very cost-effective compared with bringing the existing dam into compliance. To protect recreational interests, when the lake is filled to normal operating level, the top of the berm is submerged under several feet of water and has no impact on recreational uses of the water body.
Additionally, the lake was drained to accomplish the 2-year construction plan, but since the lake serves a vital flood control function for the city (as a detention basin), it needed to remain available for that purpose. To accommodate this, bid documents [presented] alternatives for the contractor that included temporary storage and pumped bypassing flows from storm events.
4. What time and budget challenges did your project have and what did you do to overcome them?
Certainly the need to implement all of the lake improvements while maintaining its function as a vital stormwater control basin – with all improvements being implemented in a single dry season – was a time challenge.
In addition, the entire park and lake had to be taken out of commission in a very busy area of the city. Echo Park was always seen as a recreational amenity, so having it closed for as little time as possible was paramount. Then-councilperson Eric Garcetti made a commitment to the community to have the park reopened by June of 2013. He went on to win the mayoral election for the city of Los Angeles and was able to count the Echo Park Lake Rehabilitation as a promise kept to his constituency. In fact, the mayor’s official inauguration ceremony was conducted on an island within the reopened lake.
From a technical standpoint, our construction documents made it clear there would be a lot of wet clays and organic materials. To deal with this we required the contractor to maintain a bulk quantity of a simple compound, quicklime, to assist in accelerating the drying of lake bed sediments and organic materials. The material was also a central aspect in controlling odors and dust within the neighborhood.
5. Sustainability is one of the 3 strategic initiatives here at ASCE. Describe how your project adheres to being sustainable.
Each component of the overall rehabilitation solution came with careful consideration of the environmental, social, and economic objectives.
Socially, the park has reopened with the lotus beds, which are considered a defining characteristic. The park’s popularity as a recreational amenity has returned, and it is thriving with numerous visitors who turn out each day for recreation and relaxation. The local neighborhood is benefitting socially and economically from the rebirth of the park.
As one City of Los Angeles official said, the park and the signage now make “water quality” a term people can really relate to.
Economically, the gentrifying Echo Park neighborhoods mean improved economic development for the area. The lake features revitalized recreation and activities, including the return of paddle boating, catch-and-release fishing, and other recreation. The sidewalk vendors have returned, and a lakeside café has opened within the historic boathouse which was also rehabilitated as part of a separate contract. The rebirth of the lotus plants has led to the return of the popular annual Lotus Festival. It all means growth in economic development, whether through a renaissance of the local neighborhood or the creation of local jobs with new businesses thriving at the park.