The LA Aqueduct: Mile zero

hello and welcome to today's Mono Lake moment I'm Norah Livingston the lead natural skyed of the Mono Lake committee and I'm here today to bring you a Mono Lake moment about the Los Angeles Aqueduct which has had a huge impact on Mono Lake and it's a great thing to know the pathway of the aqueduct so we're gonna start here at mile zero the Lee vining diversion dam which is just over here to my right will take you right up into the diversion in a moment but first I just want to explain how the aqueduct works and the history of how it came to be in the mono basin very briefly so in the early 1900's developers from Los Angeles and engineers started coming up to the Owens Valley and the mono basin to acquire water rights to build an aqueduct to bring water from these pristine mountain streams to the city of Los Angeles which at that time was growing almost exponentially so in 1941 after they built all the aqueduct infrastructure they started diverting water from four of the five mono basin streams that feed into mono lake and I have a little map here of what those streams are so we are standing right here on Lee vining Creek so Lee vine and Creek naturally flows into Mono Lake and the aqueduct diversion dam is right here so we're standing here at Mile zero the beginning of a three hundred and thirty-eight mile aqueduct that ends in Asilomar that a town in los angeles and the water flows into an aqueduct conduit that then passes through Walker Creek where there's another diversion dam and Parker Creek where there's another diversion dam before sending that water into Grant Lake Reservoir which is a man-made reservoir that captures water from Rush Creek which is the largest tributary to Mono Lake before sending it down through the aqueduct which actually goes through the mono craters which are dormant plug down volcanoes so that was a pretty gutsy feat of engineering to dig an 11 mile tunnel through craters with steam vents and gas bubbles and all sorts of dangers they made it safely and then the lake or excuse me the aqueduct flows all the way down into the Owens River into a few other little reservoirs and then down to Los Angeles it flows completely by gravity which is actually an amazing feat of Engineering for the time that it was being built in the early 1900s and so this aqueduct though you know it started as this grand idea to bring all this water to Los Angeles what the engineers didn't realize or didn't really care about at the time was the environmental impact of diverting this water from the mono basin and not allowing the water to flow down the creeks naturally and in timon a lake so when the diversion started in 1941 the the streams dried up below the dams and the lake started to drop it dropped about 45 vertical feet over 20 or so years and when these creeks dried up so for instance below this this dam that we're about to see the creeks dried up it destroyed the riparian habitat oh we have red cross bills flying over right now I can hear them going oh that's an awesome thing to happen during this moment lots of birds around me right now singing so as I was saying the creeks dried up below the dams and this caused a lot of damage to just the natural progression of these creeks the riparian habitat dried up and died and this destabilized the creeks and that allowed when water did flow over the dams in in high flow years for that vegetation to be ripped out and clogged channels and all sorts of damage now with the Mono Lake committee involved in the late 70s the Mono Lake Committee arrived to the Moana basin or David Gaines arrived and formed the Mono Lake Committee to Protect Mono Lake and to restore these streams and after a long court battle as I'm sure you know about in 1994 the State Water Resources Control Board mandated that DWP reduced their diversions and increase the level of the lake and constantly maintained water in the streams so DWP used to divert about eighty seven thousand acre feet per year from the mono basin now one acre foot if you imagine a football field filled one foot deep with water that amount of water is an acre foot it's about three hundred and twenty six thousand gallons or enough water for a family of four for a year excuse me and so that's a lot of water and now with new agreements Los Angeles takes 16 thousand acre feet this year if the lake drops below a certain threshold they take even less about 4,500 acre feet and if they were to drop even lower they wouldn't take any water at all but right now the lake is on the rise and so Los Angeles is able to take 16 thousand acre feet from the creeks and leave ining so you'll see behind me the pond that forms above the diversion but we're gonna walk over and look down into where this diversion comes through now when the diversions first happened when these dams were first built this was just a concrete dam across the creek and all the water possible was put into the aqueduct and when the aqueduct couldn't fit any more water the water would flow over the dam but now there's what's called a Langham in gate and this gate allows for the city of Los Angeles to control how much water's coming through but it also can control how much sediment is coming through which is really important for the downstream system so you can see there's a lot of infrastructure here a lot of movement needed there's certain accommodations for fish there's just beautiful Creek flowing lush right Tarrant riparian habitat below us and you can really see the water flowing through this Langham and gate through this dam and like I said this can be raised and lowered to accommodate the right amount of water that should be flowing down the creek for for Mono Lake this is a pretty amazing spot to be standing like I said at Mile zero of the aqueduct we have swallows flying around there's a pair of American dippers that actually nest in the aqueduct so this structure right here is where the water is flowing from the pond into the aqueduct which at this point is a tunnel that takes you to those other creeks I can mentioned but there's an American Dipper that's that has a nest inside that aqueduct and it seems and it just echoes out of this aqueduct tunnel that's pretty amazing to behold you can also see fish swimming around in the pond here above the dam and it's just a beautiful place to be in this very interesting story of the Los Angeles Aqueduct this water flows down to Los Angeles comes out of the tap their pristine mountain water snowmelt coming down from those mountains thank you so much for joining me today on this Mono Lake moment and I'll see you next week

Channel: monolakecommittee

Views: 4,463

Keywords:

Id: JIAKaRpW-Ms

Length: 8min 16sec (496 seconds)

Published: Fri May 22 2020