The Los Angeles River
The Los Angeles River was once the centerpiece of a flourishing Los Angeles region.
When Spanish colonizers initially encountered the landscape, they described it as a riot of wildflowers, wild grapes, sage, rose bushes, and sycamore trees. In 1781, the great beauty and bounty of the Los Angeles River inspired the city’s founding on its banks.
Los Angeles is part of an internationally-recognized biodiversity hotspot, designated as such because of the diversity of species it holds and the threats that they face. Essential wetland and riparian habitats support more life than any other plant communities in our region. The LA River also supported indigenous groups for millennia, and supplied sufficient water for the Spanish missions and Mexican and Anglo ranchers and farmers of the 18th and 19th centuries.
In the 1930’s, the city of Los Angeles had rapidly expanded into the areas of the river which were known to be prone to flooding. The conflict between the city’s heedless development and the river’s unpredictable nature, led the region’s leaders to partner with the U.S. Army Corps of Engineers to confine all the river’s waterways with cement encasing, fixing its course within a concrete straitjacket and defining a new standard for water management in the region for generations to come.
Today less than 5% of our original wetlands and river landscapes remain in the Los Angeles region.
Contrary to popular belief, Los Angeles is not a desert. Angelenos live in a mediterranean climate with seasonal rainfalls concentrated between October and March. The region’s average annual rainfall amounts to approximately 12” a year near the coast and 15” around downtown Los Angeles. In the mountains of the region, rainfall ranges anywhere from 35” to 52” each year. Historically, more than 80% of the region’s rainfall was infiltrated to local groundwater basins.
Today, less than 50% of our rainfall infiltrates and our rainfall flows off of impermeable surfaces into channelized waterways and directly to the ocean. In an average year, approximately 600,000 acre-feet (196 billion gallons) of precious rainwater is channeled to the ocean. This is comparable to the amount Los Angeles imports from the Owen’s Valley—approximately 157 billion gallons a year.
In 2012 to 2017, we saw the effects of the last century’s water management practices come to a head as California and the Los Angeles region suffered from the largest drought in recorded history. This and other factors forced the region to reconsider its stance on water management. The region is moving toward comprehensive watershed management practices, where the entire watershed, not just the river, is taken into consideration to evaluate and develop not only wholistic water management practices but also climate resilient communities.
The choices we make about the Los Angeles River determine the city’s economic viability and social health. The benefit of a concrete river is singular—it swiftly transports rainwater out of the city and into the ocean—yet deprives the city of all other essential ecosystem services. We now understand, from examples across the world, the critical need for protecting floodplains as part of reliable, regenerative flood management strategy.
Living rivers and healthy watersheds provide profound benefits to the cities they nurture. They provide water supplies, filter out water and air pollutants, move sand to ocean beaches, provide critical habitat, sequester carbon, regulate floodwaters, and create cooling oases for relaxation and recreation. We have an imperative to prioritize the health of the river and its contributing watershed over business as usual, and to make the complex decisions necessary to take regenerative actions that will provide for generations to come.
A healthy Los Angeles River and its watershed are vital for a climate-resilient future for Los Angeles. At The River Project, we believe that the health of the Los Angeles River is intricately entwined with a healthy Los Angeles watershed and will only be truly realized through programs and initiatives that develop the two in tandem.
Banner image by Smjafry (Own work) [CC BY-SA 4.0 (https://creativecommons.org/licenses/by-sa/4.0)], via Wikimedia Commons