For thousands of years, winter rains in the Los Angeles River watershed created a year-round creek.

In the summer months, save for in aquifer-fed areas like the Elysian Valley, water slowed to a trickle.

Today, during the summer months, the concrete channel of the Los Angeles River carries a higher and more constant volume of water than ever before. This increased flow comes primarily from water reclamation plants (WRPs) and, to a lesser degree, from street runoff.  The majority of the treated water flows from the Donald C.Tillman WRP, located adjacent to the Sepulveda Basin Wildlife Reserve. The Tillman adds approximately 60 million gallons of reclaimed water to the LA River each day.  It also supplies water to Balboa Lake, the Japanese Garden, and two golf courses located in the Sepulveda Basin.  Additional treated discharge runs to the LA River from the Burbank WRP, the Los Angeles/Glendale WRP in North Atwater, and the Whittier Narrows WRP on the Rio Hondo. 

These wastewater plants take in sewage and grey water from toilets, sinks, showers, and drains.  They then clean the waste water via an array of technologies, including settling, aeration/digestion, and filtration.  The result is treated water that, while not safe to drink due to higher-than-normal bacteria counts, is nearly as clean as fresh water.

This year-round volume of reclaimed water has made an impact on the river’s ecology. The constant flow has aided the expansion of plant life, birds and fish populations in the scenic, soft-bottomed sections of the river. At the same time, it has allowed the proliferation of algae, and of non-native fish and plant populations. These include the castor bean plant, and  Arundo donax, an invasive bamboo  The introduction of the mosquito fish, meanwhile, has helped decimate the river’s native frog population.

Environmental plans are underway to increase the Southland’s use of this reclaimed water for landscaping and industrial uses, which would help reduce the county’s dependence on imported water. Unfortunately, this would also reduce the amount of water flowing into the river.  If the reclaimed water were to be diverted for other uses, the river channel would become drier than it is today.  This proposed reduction in volume will, hopefully, proceed with care in order to ensure that the habitat now supported by the river does not unduly diminish.

In the winter months, with over 60 percent of the river’s urban watershed now paved or built up, the rainwater has a much harder time seeping into the ground to replenish the region’s subterranean aquifers. Instead, the water quickly runs into storm drains, which lead to over 400 miles of concrete-lined tributaries. These feed the main river channel, a mix of runoff and wastewater that, ultimately, empties directly into the Pacific.

The winter storms also flush the city’s streets of oil and radiator and transmission fluids. They wash away trash and fluids that thoughtless residents have dumped into storm drains. As this pollution drains from the river into the Pacific, it creates water conditions far more hazardous than those resulting from the WRP’s discharges.

Much progress has been made in the last decade to clean up storm water pollution. The Federal Clean Water Act has motivated both county and city departments to step up their stormwater pollution abatement projects.

Today, the city’s Watershed Protection Division conducts 23,000 semi-annual inspections at local industrial and commercial sites, including restaurants, gas stations and vehicle maintenance facilities. The city has also set up a toll-free hotline (1-800-974-9794) for residents to report abandoned waste, accidental spills, clogged catch basins, and illegal discharges into the streets or storm drain system. Callers can also request public education materials, including brochures, stickers and posters.

The Bureau of Sanitation now monitors ocean water quality at 18 coastal sites between Malibu and Torrance each day. When bacteria levels exceed acceptable amounts, the affected beaches are closed.

Each year, LA’s Bureau of Sanitation crews clean up the 30,000 storm drains, screens that have been placed at street level to catch debris. A fleet of 23 trucks, outfitted with suction hoses and storage tanks, vacuum trash out of clogged catch basins. This prevents street flooding, and helps keep trash from reaching the river.

The California Department of Resources Recycling and Recovery provides recycling services. The Los Angeles Bureau of Sanitation also offers a variety of oil recycling centers to encourage residents not to dump used oil in the street.

The leading Santa Monica environmental group, Heal the Bay, has partnered with the Los Angeles Department of Public Works to paint signs on storm drains, which remind residents that each drain is a direct artery to the ocean. FOLAR holds El Gran Limpieza, an annual cleanup during which thousands of  volunteers remove over 30 tons of shopping carts, tires, and other trash from the river.  Every agency and every Angeleno needs to do their part to prevent the build-up of trash in the river and on beaches, and to protect the city’s groundwater supply.