The Los Angeles basin is a coastal plain created by the sediment deposits of rivers flowing out of the Santa Monica and Santa Ana Mountains, as well as the San Joaquin and Puente Hills. As the delta grew into a solid landform, the basin was crisscrossed with rivers, each winding through the smoothest courses of the landscape. Seasonal snowmelt meant that the rivers shrunk and swelled; creating marshland and leaving rich, mucky banks. Without human intervention in the landscape, these wetlands would still be a dynamic part of the Los Angeles basin.
The Rio Hondo and San Gabriel Rivers flow from the Angeles National Forest in the north down to the central growth point of the basin, out to the Pacific. The Los Angeles River in the northwest and the Santa Ana River in the southeast are also drawn to be incorporated into the Emerald Necklace Plans. With 17 miles of trails and greenspace for recreation and education spreading through the city, public and private support is necessary to achieve success in promoting their visionary green infrastructure goals.
WETLAND PROJECTS
The City of Los Angeles proposed the South Los Angeles Wetland Park Project to help meet the Los Angeles Regional Water Quality Control Board’s (RWQCB) TMDL requirements. TMDL improvements help ensure that the Los Angeles River watershed and beaches are maintained for their recreational uses, as well as providing natural habitat. Additional values in creating the wetland park were historical and educational: old railroad and structures from the site’s industrial past were kept, and aid in the design’s ability to facilitate community gathering and wildlife viewing.
Completed in 2010, the stormwater treatment wetland is just larger than 4 acres, and the entire site – including parking lot – utilizes Best Management Practives (BMPs). The park boasts trails, boardwalks, observation decks, picnic areas, a natural rock-garden seating area, educational signage, and a renovation of an 81,760sqft pre-existing building for mixed public use.
The Wetland Park has assisted in minimizing the introduction of pollutants such as bacteria, oil, grease, gasoline, suspended sediments, and heavy metals.
LA’s Department of Public Works proposed the Hansen Dam Recreational Area Parking Lot and Wetlands Restoration Project as a stormwater treatment measure for three large parking lots. A part of the Los Angeles River watershed, the site’s improvements were needed to ameliorate the water quality standards for the city and for the impacted ecosystems. The bioswales, sand filters, and treatment wetlands will capture and treat urban pollutants and keep water onsite for landscaping.
Near the Hansen Dam, there are sensitive habitats and endangered species the need to be protected.
One of the last remaining wetlands of the Los Angeles Basin is the Ballona. The Ballona Creek and adjacent wetlands were ungrazed even as cattle roamed over the rest of the basin. In the 1930s, the creek was channelized with concrete walls, preventing saltwater into the brackish marsh and controlling the spring snowmelt flooding that mix freshwater into the ecosystem.
The 640 acre Ballona Wetlands Ecological Reserve is supported by the philanthropic Annenberg Foundation with over $50 million for an educational center
The project seeks funding from the “Clean Water, Clean Beaches” Measure, and as you can see from the aerial photography, the area is adjacent to waterfront properties.
Los Angeles is even creating a wetland “pocket park” to treat water and capture storm flows! Less and 1.5 acres, the design below was approved by the Los Angeles County Board of Supervisors to recreate wetland conditions in the dense urban fabric at the corner of Via Marina and Tahiti Way.
Every little bit counts!
For more information, please see these resources:
http://watershedconservationauthority.org/plans/EmNeck.html
http://www.lapropo.org/sitefiles/lariver.htm
http://southcentralbungalow.wordpress.com/2009/06/16/south-los-angeles-wetlands/
http://www.lacountycleanwater.org/app_pages/view/663
http://www.ballonafriends.org/history.html
http://www.kcet.org/updaily/socal_focus/history/la-as-subject/historical-ecology-of-ballona-creek.html
http://articles.latimes.com/2013/feb/05/opinion/la-ed-ballona-wetlands-annenberg-foundation-20130205