Thursday, September 13, 2007

LA's Hydrological Freeway

This detail from the 1902 map of Los Angeles looks south toward downtown from a point high above Burbank. The Hollywood sign perches near the top of Cahuenga Peak in the middle. Winding around the Hollywood Hills in the foreground is the Los Angeles River.

Like a Hollywood cliche, the River went under the knife during the 1940s and emerged completely changed. No longer a meandering desert stream, the LA River is now a straightened, paved trench. It's visible in the present-day aerial view below, following roughly the same course as before:

The paving project followed a large 1938 flood, which itself was partly the result of burgeoning development in the river's watershed. The straightened, paved channel was meant to deliver floodwaters as quickly as possible to the ocean. But most of the time, the river flows as a mere trickle through a wide concrete plain, which makes the renovated River an irresistible playground for movie car chases. The LA River has played a supporting role as a racetrack in Repo Man, Grease, Terminator 2, and many other movies.

Look familiar? Photo by OPHOTN
As a storm drain, the new LA River works pretty well... although it still floods from time to time. As a river, though, it's a mess. The water is severely polluted with runoff - garbage, oil, dog shit, etc. - that flows off of every parking lot and freeway in the San Fernando Valley. And wildlife isn't exactly thriving there, although waterfowl and fish, taking what they can get, do live there. After half a century of living with the paved river, then, Los Angeles is talking about restoration, and some of the concrete may come out to provide better water quality, habitat, and absorption of stormwater.

The manifest destiny of the LA River may end up looking less like a post-apocalyptic movie set and more like its frontier condition.


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