Third Intake Documentary

water without it life as we know it would cease to exist no one understands this better than those who live in the desert Southern Nevada's water supply originates in the Rocky Mountains snowmelt drains into the mighty Colorado River which winds its way through the Southwest States to Mexico along its course a series of dams and reservoirs manage the rivers flow delivering water for nearly 35 million people and more than 5 million acres of irrigated cropland many communities are dependent upon the life-giving waters of the Colorado River but none more so than the city of Las Vegas Las Vegas is located in the Mojave Desert without a reliable water supply in Las Vegas simply can't exist so there's nothing more important than being able to guarantee that nearly 90% of the Las Vegas water supply comes from Lake Mead reservoir fed by the Colorado River but Lake Meads water level has been dropping putting Southern Nevada's water system at risk since 1999 the Rocky Mountains has been going through a very severe drought we've always known that droughts are part of the natural cycle what's most concerning about the current situation is that we're seeing a natural drought combined with the beginning of climate change the lake is now at less than 50% of its capacity the lowest level since the reservoir first filled in the 1930s below water levels of the lake threaten critical infrastructure used to access and deliver water to Southern Nevada if the lake continues to drop our upper two intakes will no longer be able to pull water so in the face of these declining reservoir elevations we're constructing a third intake in to Lake Mead in order to access water from the coldest deepest part of the lake with the drought continuing unabated construction of the third intake is a race against time I feel pretty honored to be down there you know it's it's not easy work you know but by the end of the day you feel like you've accomplished something and you know a little sweat never hurt nobody in take number three will draw water near the bottom of the lake its construction will be one of the most challenging tunneling projects ever attempted to build it will require excavating a shaft more than 600 feet deep a tunnel boring machine will be lowered to the bottom of the shaft and excavate a route 3 miles long under the lake the intake structure will be built suspended from a barge near shore then tugged out on the lake lowered into a pit and secured with concrete finally the tunnel boring machine will connect with the intake structure allowing the lake water to flow through tunnels and pumping stations to reach the water treatment facilities each phase of the project is a daunting challenge made all the more difficult by the intense pressure working so deep underground and below Lake Mead the tunnel-boring machine will face up to 15 atmospheres of water pressure higher than any previous tunnelling project has ever encountered the geology of the area poses another great challenge unstable rock conditions riddled with faults act as conduits for water to travel into work areas these conquer to overcome the obstacles of the harsh environment it will take ingenuity and creative solutions but it is of perseverance of crews working day and night over the course of seven years that will lead the team to success working underground is dark dirty and wet it takes an exceptional mindset to do this work I like this kind of job I love being on the ground grilling including dynamite TV Am's I like it to excavate the shaft workers apply a drill blast and muck technique the first step is to drill long holes into the rock face workers then insert dynamite into the holes after the dynamite charges that meant the crews muck out the rock debris and load it into buckets for removal to the surface bucket by bucket the workers slowly make their way deeper into the earth each bucket holds 8 cubic yards of rock and weighs 35,000 pounds when loaded working day and night it takes over a year to reach the full depth over 600 feet below ground at the bottom workers excavate a large chamber and starter tunnel which makes room for the incoming tunnel boring machine then on June 28th 2010 the workers get a shot five of us down here you know we were down on the ground and seen the hot water changing Connor that's what I knew something was gonna happen you know so I'll call to call these guys on the table had that basket ready a torrent of mud gravel and water surged into the work area a little bit scary no I won denied it everybody was scared but then God would call got my guys out everybody same matter over the next four days water and approximately 66 hundred cubic yards of mud and gravel flowed into the starter tunnel bearing equipment and bringing the project to a standstill I've personally have never seen anything like this myself engineers launched studies to investigate and identified a series of near-vertical faults that channeled the material into the work site this just goes to show that despite your best efforts and the best information you have on hand that things that are underground are almost impossible to completely predict and Mother Nature is a as a powerful entity and sometimes she wins the inflows are a major setback crews spend the next year recovering and pursuing a new route for the tunnel that skirts the problematic fault zone meanwhile crews excavate another tunnel to join the shaft to the existing tunnels and pumping stations that convey water to the treatment facilities on the surface the german-made tunnel-boring machine is assembled this machine is named Kokopelli which is southwestern Indian spirit or God if you will Kokopelli is a technologically advanced and robust piece of machinery designed specifically for the conditions of this drive normally a tail shield could be as little as an inch thick this one happens to be three inches thick just because it's got to be able to withstand that pressure and that goes throughout the machine all the steel structure of the machine has to be built in order to take that pressure so this machine weighs about 900 tons lowering the TBM sections down the shaft requires precise maneuvering the shaft is a 30 foot diameter and the TBM is 23 and a half but if you look at it as a square from above it's only got about 1 to 4 inches of clearance so it'll take about 12 hours to descend to the bottom while underground crews prepare the TBM at the beginning of the round marine crews are busy working at the intake site two miles offshore they are excavating a deep hole in the lake bed where the intake structure will be placed working out on the lake comes with its own set of trials part of the challenges that we face is the weather the high winds which also create three to four foot seas when it's 30 mile an hour winds like it is today marine crews have removed fourteen thousand cubic yards of overburden from the lake bed floor and are now blasting away the bedrock over the course of a year and a half they will detonate 24,000 charges throughout the marine work a remotely operated vehicle acts as the eyes of the crew working above the ROV makes it possible to avoid dangerous deep water dives during the intake operations it's basically a camera platform that we fly around and observe what what's going on it has a small manipulator on it that allows us to do a certain amount of operations with it today that comes in handy going to be checking the detonation cords and make sure that they're all connected but nothing came loose why we were coming down whoops a detonation line of one of the charges has become caught on an edge of the transport frame if the ROV can unhook it the crew will save ours okay should be clear I will say nothing ready every day the whole underwater becomes a little deeper and wider off-site crews are manufacturing the concrete ring segments that will be installed by the tunnel-boring machine and serve as the final liner of the tunnel the segments are manufactured to tight tolerances they must vary in size by no more than one and a half millimeters the precise size of the segments is crucial to the performance of the tunnel as the Rings must fit together and create a watertight seal that is strong enough to withstand the intense hydrostatic pressure and all over 14,000 segments will be cast for this tunnel drive 600 feet underground the TBM Kokopelli has begun mining the concrete ring segments will make up the tunnel liner installed within the protective shield of the machine when ground conditions are favorable meaning the rock formation is cohesive and groundwater minimal the machine will mine in open mode the material is carried through the machine by a screw conveyor and deposited on a conveyor belt to transport it through the tunnel when ground conditions are poor and groundwater is flowing at high volumes the TBM can switch into a closed or slurry mode in closed mode bentonite slurry is pumped to the face of the Machine and the excavated material mixes with the slurry and is pumped back to the surface where the bentonite is extracted and reused every 6 feet the TBM stops and crews work to install another concrete ring the tunnel-boring machine pushes off the newly completed ring to move itself forward then excavation begins again right now we're having problems with our water Dewayne West is one of three qualified operators of the TBM the hardest part of this job is watching everything all the time you've constantly got to be watching your pressures on everything your grout your thrust cylinders your articulation your cutter head then you're looking at the VMT to make sure that you're staying on line and grade so you're you're steering and making adjustments there and when there's problems trying to figure out the problems interpreting the pressures on your screens will tell you what the ground conditions are like outside sometimes it's very hard to interpret that information hello even under ideal conditions that the TBM operators job is stressful there's a restriction somewhere because we were flooding everything down here that's blowing off and on this drive conditions are proving too rarely be ideal yep people are working on it Chris it's been very difficult because of the pressures it's the highest pressure machines ever been at in the world to mine through the ground normal jobs I've been on before we're anywhere from three to six seven bar we were encountering up to thirteen point eight bar so it's definitely abnormally high we had to mine at average of 12 point 5 to 13 mar 2015 11 due to poor ground conditions and high pressures the team is unable to access the cutter head for routine maintenance forcing the cutters to work much longer than they were designed for finally the TBM enters better ground conditions allowing for an inspection of the cutter head ground water flows through at a rate of four thousand gallons per minute working in these conditions requires heroic effort the team makes a shocking discovery the center part of the of the cutter was completely destroyed some of the structure of the cutter head was banded and damaged from the overeating and pushing his machine pushed a lot workers excavate a narrow niche to access the front of the machine and welders are able to rebuild the cutter head on the water marine crews are building the intake structure which the TBM will eventually bore into on the bottom of the lake the structure is suspended in the water from a barge around its perimeter long cables attached to each corner and threaded through strand jacks will serve to lower the structure to the bottom of the lake the intake structure is complete and the marine crew gathers before dawn to prepare for a big day we were bringing the intake structure out today it's two years worth of planning two years worth of work two years worth of digging a hole sixty feet deep at the bottom it's pretty significantly maritime tradition requires a dedication before the voyage begins if that bottle doesn't break I have to go for us reverse the bad luck I've got all the projectory on it I can get on it the angers are cut and it's time to push off at more than 90 feet tall and 1400 tons moving the structure in the lake presents quite a challenge all eyes are on the weather the bark is a big sale and if the wind will push you off course and if it pushes you all forth then you run a risk of running aground as the barge rounds the cove the wind suddenly picks up forcing the tugboats to operate at full power to stay on course despite the wind if the intake structure safely makes its way to meet up with the crane barge on the lake great job on bringing this thing out but exactly the best conditions and y'all did a great job the intake structure begins its slow descent to the bottom of the lake to secure the intake structure to the lakebed floor requires pouring eleven thousand cubic yards of concrete at a depth of three hundred and fifty feet the logistics of such an undertaking require new techniques the project is unique in itself it's never been done before anywhere in the world it's at a depth the concrete has never been placed not in a tree me system we had to take everything in and put it into one system and then fix problems as they came along to make each phase work engineers worked for eight two months to develop a method of delivery and a specific concrete mix designed for the unusual environment the concrete that has to stay very fluid during the transportation and getting it out to the placement barge with the ready mix trucks is very difficult because it takes around 2 hours to get it there so after the two hours the concrete has to be workable so that it will flow down the 350-foot tremie pipe the pour itself is a marathon running around the clock for 11 days straight three barges loaded with concrete trucks rotate continuously from the shore to the site on the lake as if the task was not challenging enough Lake Mead throws in one more trial for the crew to overcome five days into the pour the wind picks up this must be 75 miles an hour the tugs can't push the part just like that it's too much weight today's gonna challenge us guys cruise wait out the worst of the storm and the barges are soon back to work finally the base of the intake structure is fully submerged in concrete for the marine crews their job is complete and they depart knowing they've had a hand in something momentous being a part of this job has never been done before so it's gonna be like the crowning moment in my career that's kind of special to me I like it after three years of tunneling the TBM Kokopelli is approaching the end of her journey took so long over right in the am out all right good morning guys right now we are halfway through push 24 25 when we hit ring 24 27 is when we should be pushing through the intake structure very close the whole through has been a long time coming you know thinking about this project you know the end seems so far away it never really seemed real the crew below advances the TBM at a cautious slow pace above and below-ground on land and from the water all eyes are watching for signs at the separation plant pieces of fiberglass rebar proved that the TBM is boring through the soft eye of the intake structure kind of waiting for this total force that should drop down about 5,000 kilonewtons only haul through that's when we'll know a call comes in from the marine barge on the lake where workers report seeing bubbles rise up through the water you get some more bubble was there at last there is no denying the TBM has hold through into the intake structure it's all over finish six errors is over okay over over a long time coming but it's done yeah good job they're very proud of what they have accomplished after all the hard obstacles that we had on this job over the years people that work together to get it up you know to get it done but without them we would going no place feels great feels real good all of the preparations that went into excavating the tunnel are now reversed all this structure would be cutouts the cylinders the main bearing structure everything yeah for the outer ring of the shield the outer ring of the shields will be welded together and I'll actually be part of the tunnel the TBM pieces miles of pipe utilities and rail lines are hauled up the shaft the tunnel is ready to equalize the pressure from the lathe the tunnel is filled with water from the surface there is just one last milestone left in the project a temporary bulkhead and the intake riser is all that separates the lake from the new tunnel today it's coming out today was a big milestone finally after almost 7 years we can call it complete this was a very difficult project we've set the world record for mining at the highest pressure where the tunnel boring machine in the world to date we encountered variable ground conditions unstable ground and very high pressures so we had to really fight for every inch along the way it was really the workers that the contractors engineers everybody that's involved coming to work and bringing their best and putting our heads together and working through these challenges that's why it was such a success uncertainties of drought fuelled by climate change will undoubtedly continue to challenge the arid Southwest but by looking ahead and planning for the future the Southern Nevada Water Authority is mitigating some of its impacts for the people of Las Vegas the years of hard work and in G's construction of the third intake have secured a reliable delivery of water to their homes the very lifeblood for a community in desert you

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Views: 296,768

Rating: 4.6930842 out of 5

Keywords: third drinking water intake, intake no 3, third straw, lake mead, colorado river, southern nevada, las vegas, henderson, drinking water, tunnel project, underwater

Id: Wi-W5hcRN4E

Length: 28min 24sec (1704 seconds)

Published: Tue Mar 15 2016