Rehabilitating One of the Largest Ecosystems in Southern California

Rehabilitating One of the Largest Ecosystems in Southern California
City of Los Angeles Los Angeles, California, USA
Faced with an increasingly intrusive number of water quality concerns, the city of Los Angeles sought to rehabilitate its largest freshwater ecosystem by implementing a sustainable, forward-thinking improvement plan.
Machado Lake is one of Southern California’s largest coastal wetlands, lying within an area that was annexed to the City of Los Angeles in 1906. As freeways, heavy industry and dense urban communities developed around it, the lake was protected as part of the only remaining regional park in the Harbor City neigh­bor­hood of Los Angeles. Over time, sediment accu­mu­la­tion, toxic pollutants, trash and urban runoff degraded the lake and the surrounding habitat, leading to the lake being designated as an impaired water body by the state. 

CDM Smith partnered with the City of Los Angeles – Bureau of Engineering, LA Sanitation, and Recreation and Parks to develop a design that melded engineering technology with natural treatment systems and resources. 

The city’s goal was to improve the lake’s water quality and enhance a large green space in an area with significant envi­ron­men­tal challenges and minimal recre­ational oppor­tu­ni­ties. Cont­a­m­i­nated sediment was dredged from the lake and a lake oxygenation system was installed to further enhance the water quality. With the completion of this project, Machado Lake is now a sustainable community resource for all to enjoy.

The first phase of the project repaired the Wilmington Drain that feeds the lake, including regrading and reinforcing the channel banks to withstand high velocity flows, removing non-native vegetation, and installing a trash net system at the upper end of the channel to prevent debris from entering the channel. Addi­tion­ally, the channel was revegetated with native plants and three permanent, vegetated access ramps were installed in the channel for maintenance activities. 

The second phase consisted of Machado Lake improve­ments, such as dredging lake sediment and capping the lake bottom with a bio-layer that promotes aquatic habitat while preventing contaminant rein­tro­duc­tion construct­ing oxygenation removal systems; installing aquatic habitat features, and reha­bil­i­tat­ing the dam structure at the south end of the lake. Invasive vegetation was removed and replaced with native plants and grasses, and natural resources were conserved using native plants and reclaimed water for landscape irrigation.

New park features provide the neigh­bor­hood with a green space to enjoy for generations. Four fishing piers and two shoreline fishing platforms were constructed, which allow catch-and-release fishing. In addition, paved pathways, trails, bridges and benches provide the community safe means to explore and enjoy the recre­ational amenities of the park. The project was completed ahead of schedule and opened to the public in 2017.

One of the largest ecosystems in southern California is once again a green jewel amidst one of the world’s largest cities. Machado Lake will be an important resource for the community and a wise investment in the future of Los Angeles.

Protecting a Precious Habitat 

The Machado Lake ecosystem is one of the largest remaining coastal wetland ecosystems in Southern California, home to a wide variety of native fish, birds and insects.

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