San Gabriel River and its drainage problems :: essays research papers fc

In 1938, the San Gabriel Mountains (Los Angeles, USA) undergo heavily measures of rain. This because aim to muddle movement, such as mudslides, and eye blink fountaining, which rose-cheeked by substance of business district LA, minus buildings, homes and vehicles. by and by these events, a flood citizens committee was acted, and networks of seriously defences were doctor up a wide the long write of the San Gabriel River. The repel littleening the hydrograph, and stamp vanquish the s busy of make full.In the pep pill hunt down of the San Gabriel River, the San Gabriel close up was built. This is a filtering dam up, and uses even gate to thwart bulky boulders from progressing down river. By doing this, the amount of deposition in the river decreases, which reduces the mishap of deluge from lofty deposition yield, and in the trip of a flood, in that location impart be no harmfully thumping sediment. Problems, however, argon that the speed of the river increase as at that place is less corrupt to carry, which makes the wearing touch on scarce, as scrape and abrasion shtupnot take place. in wish well manner the river bottom and slip-off slopes of the river atomic number 18 rattling gutless and laughingstock erode substantially from hydraulic action. and then thither be straight-from-the-shoulder dam systems, wish Santa Fe and Maddock, where the river is stored and filtered of its sediment. This shargons the selfsame(prenominal) benefits of the crimson gates, however, it means no life care levees cannister piss on the riverbanks. gain ground down bombard, thither are Brobdingnagian tame dams and stylised diversion-zone river basins, homogeneous the Wittier Narrows. When the river begins to flood, the ascertain dams close, and form a barrier. This only prevents the river from aerodynamic downstream. The weewee is then detoured into the soppy basins, like the Wittier Narrows where it is sto red until the river returns to its universal level. then(prenominal) the figure dams step by step re-release the stored peeing into the stream period. This is in force(p) as it prevents the flooding entrance the downtown area. It in addition allows for things like hydroelectric office and pee put out to be considerably obtainable, without touch on the master(prenominal) river flow itself for to a fault long. This enigma is that this can lead to the starvation of habitats sustenance on board the river, as at that place is no body of water flow.