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Click here to download a pdf version of the slide show, with three slides per page and lines for notes.

=media type="custom" key="25406666"= [|Los Angeles Storm Drain Development 1910 to 2010] By Steve Duncan This map-- centered on downtown Los Angeles, the historical center of the city-- shows the growth of underground storm drains as they have replaced the many natural small waterways and drainage routes that were part of the landscape prior to urbanization. The red lines show the storm drains. In this map, only the underground storm drains are shown, ranging from round pipes only 18 inches in diameter up to vast tunnels more than 20 feet wide and 20 feet tall. In addition to the underground tunnels depicted here, Los Angeles also has more easily-visible above-ground waterways like the Los Angles River, which today is a concrete-lined, open-channel storm drain. (Usually it is called a "flood control channel.") Those very obvious above-ground channels, however, probably lead many people to believe that most of the the city's drainage and flood-control infrastructure IS visible aboveground. As this map shows, there is quite a lot more underground. This invisible network of infrastructure has helped to shape neighborhood growth, differential real-estate values in different parts of the city, and the overall patterns of urban development and flood-risk valuation over time. Los Angeles is often thought of as an arid, desert environment, requiring water to be imported into the city. In the 19th century, however, there were many above-ground springs and streams that flowed year-round and the underground aquifer, or water table, was very close to the surface in the broad, flat plans that stretched between the Los Angeles River and the Pacific Ocean (today's downtown Los Angeles, Koreatown, West LA, Santa Monica, Venice, etc). Many of these tunnels shown here replaced those former above-ground streambeds so that when rain did come in its occasional torrential bursts, the water would quickly flow out of the city and to the ocean so that new houses and real-estate would not be inundated. As urbanization progressed in the 20th century, more land was paved over and became impermeable to water: roads, driveways, and houses themselves. Thus SAME AMOUNT of rain would produce MORE AND MORE run-off water, because those occasional but heavy rainfalls could not be absorbed into the ground. Instead it all became run-off and inundated the surface of the city. In this way Los Angeles itself has created the problem of flooding... More drains were built to carry the increasing water away to prevent floods. At the same time, the drains themselves carried the water through impermeable tunnels and prevented it from soaking into the ground and recharging the water table. Over time, and particularly in the period of about 1890-1940, the former year-round springs and streams dried up, and wells became useless. Thus Los Angeles, bizarrely, managed to create a desperate water shortage for itself at the same time as it was increasing the threat of flooding! This is a remarkable and remarkably complicated historical story, but it is similar to patterns and problems in many cities through the 20th and now 21st century. How can cities address these problems, and deal with urban water issues in realistic, productive, long-term ways? I think making the hidden infrastructure that has been involved urban development more visible might really help more people to understand just what exactly is going on under their feet.

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[|The Water Cycle and Cloud Formation (Amazon Video)]



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