Report, Flood control in the Moapa Valley, circa 1934

Flood Control in the Moapa Valley By Charles MacKnight Sain Friday, February 3, 1934, was a memorable day in the history of flood control in the Moapa Valley. That day the Ely company of the CCC boys, under command of Captain Everett K. Higgins, began pouring concrete for the spillway in the first of three units for flood control. That spillway is all important. Without it the 1600-foot long dam and dyke, now being thrown up across the valley,would simply be the in the alluvial deposit of the Meadow Valley wash. That spillway, to make it safe, requires a thousand yards of concrete. It is 100 feet wide, has a vertical fall of 18 feet, 32 feet on the slope, has an upper lip 40 feet wide extending beyond the ends of the spillway and another lip of about the same dimensions on the floor of the wash. This concrete flooring is only one foot thick but that is ample. The edge of the upper apron is only three feet above the adjacent land. That three feet represents the depth of water that can back up and spread out over they floor of the valley before the flood begins to spill back into the channel of the Meadow Valley wash. That is the depth at the spillway, but the water will be a little deeper back along the foothills as the land slopes gently to the east. That spillway is designed to take care of a run-off of 7,000 cubic feet per second. That is supposed to be the possible maximum flood. Graham Quait, the engineer on the project, said a flood of 1,000 second feet, running 12 hours, would make a depth of only one foot spread out over 1,000 acres of the valley. Page 2 A thousand cubic feet per second is considerable flood water. The flood of January of this year, when Los Angeles suffered great disaster, was only 330 cubic feet per second in the Meadow Valley wash. Even that took out 10,000 cubic yards of the new earth work of the diversion dam on this first unit. The CCC boys were just getting started and could not protect their work. Now they have the dam high enough to turn any ordinary flood out on to the flat. The big flood of 1910, 34 years ago, i3 variously estimated between 5,000 and 10,000 cubic feet per second. William R. Gann, then a young man, says it struck his father's farm in the upper end of the Logandale section of the Moapa Valley at five o'clock in the morning of January first. Mr. Gann says they had received a telegram the night before from Caliente that a flood wan coming but they were not alarmed and anyway there was nothing they could do about it. That flood was a mile wide in the Moapa Valley and Mr. Gann says it was deep enough to swim a horse. It deposited a foot of sand on 60 acres of young alfalfa on the Gann place. It left four feet of sand on the Gann ranch where Louis Adams' house now stands. It swept away five acres of cabbage for Joseph H. Robison and heads of cabbage were reported floating down the Colorado all the way to Imperial Valley. It buried to the top of the poets a string of wire fence for Edwin Marshall. Mr. Marshall rebuilt and two years later the silt from another flood again buried his fence. As it is now Mr. Marshall has a three-storied fence around his place, one story above ground and two underneath. That same danger confronts the valley today. Another flood might come at any time and bury every farm in the valley. And the worst of it is this new sand carries an excess of alkali which has to be leached out before the land can again be made productive. Page 3 But if the plan formulated by County Agent John H. Wittwer and others for a three-unit project is carried out this menace to the valley will be permanently removed. The first of these units is the Higgins dam and spillway seven miles above Glendale. The dam deflects the water from the channel and spreads it out over a flat covering 1,300 acres. This flat is about a mile wide and three miles long. The spillway is at the lower end toward Glendale and the difference in elevation between the spillway and the dam is 60 feet. Thus it is evident that the flat does not serve as a reservoir to store flood water. But the theory is it will act as a table or apron and allow the silt to deposit and waste the water by evaporation and seepage. To keep the water from flowing back into the channel before it reaches the spillway a dyke is being constructed three miles long. This dyke is two to eleven feet in height. It will be covered on top with brush and wire netting to keep the sand from drifting. The entire unit requires the handling of 95,000 yards of dirt and gravel, not counting the 10,000 yards that was lost. The dam will be 24 feet high and on that Friday was within four feet of the top. A depth of 12 feet was excavated in the loos" gravel down to hardpan to make a foundation for the dam. The upper face of the dam h^n a slope of 3 to 1, and the lower face 2 to 1 and both are protected by rouble work of boulders. The width of the dam on top is 40 feet, four times as wide as necessary, thus giving ample assurance there can be no break. And this provides for building the 3am still high in case the silt fills up the flat on the course to the spillway. The engineers refused to approve a spillway over the top of the dam. But calculations were made for excavating a channel Page 4 and cementing it for a spillway around the wast end of the dam in case the flood water should ever be wanted for storage. On that particular Friday the CCC boys had moved 40,000 cubic yards of dirt and gravel toward their goal of 95,000 yards. The company is 100 strong and works in two shifts, night and day, all but the horses. They have two caterpillars, four dump trucks and 50 horses on the Fresnos. The ,caterpillars are run ti?o shifts for the reason the boys want to finish the job by the first of April. The boys are part of the forest service and their forestry work Is laid out to start in April. These CCC boys are not idling their time away. They are doing men's Fork. They try to see how much, not how little, they can do. There is rivalry between the night and day shifts to see which can get the most work cut of the caterpillars. The result is a number of the boys have been given outside jobs, men have been promoted from the ranks, and the company has been recruited for the third time from the reserves in Ely. The boys are in the direct charge of T. E. Tangrin, acting super-intendent of the Moapa and Alamo forests. Captain Higgins and his staff conceived the idea of inviting the people of the Moapa Valley to a weenie feast on this particular Friday evening to let them see what was being done for the pro-tection of their farms. The staff comprises A L Ferguson, camp superintendent; Lieutenant Boerlin of Reno, Nevada; Lieutenant Larkin of Glendale, California; Stephen Likens, construction superintendent; Graham Quait, engineer; frank Natusch, purchasing agent; Frank Mahoney, cement foreman; William Larson, team foreman; Shorty Griffin, night foreman. Page 5 These with their guests gathered around a huge campfire at the dam and ate weenies and dill pickles and drank coffee. Mr. Tangrin acted as master of ceremonies and introduced the speakers. Captain Higgins spoke for the CCC boys. Mads Joregensen spoke for the people of the Moapa Valley. The Muddy Valley Irrigation Company, whose first surveys for flood control are now being used in this construction work, was represented by Edwin Marshall and Elmer S. Bowman. The principal speaker of the evening was Luther M. Winsor, chief engineer of the bureau of Erosion and Flood Control. This is a. new department created by the Government to guard Mead Lake, the reservoir behind Boulder Dam, from the deposition of silt. Mr. Winsor was then on his way to his new headquarters at Albuquerque, New Mexico, and stopped off here for this event, for the next year his principal work will be on the Navajo Reservation. But he will return to inspect the work for flood control on the Muddy river. Mr. Winsor first made the acquaintance of the Moapa Valley in 1898 when he worked in a brickyard at Overton. For the last fifteen years, while an engineer in the service of the Agricultural Department at Washington, he has given particular attention to the problems of flood control in the Moapa Valley. Mr. Winsor was here in December with Congressman Scrugham and together they went out to Boulder City and secured equipment to outfit the CCC boys at the Overton camp under Captain Miller. Mr. Winsor says this equipment was secured for the particu-lar purpose of construction of the Equalization Dam on the Muddy river just above Wells Siding. Page 6 Mr. Winsor greatly deplored the fact Captain Miller's company had used this equipment in building a road into the Valley of Fire, and had not yet got started on the Equalization Dam other than to clear the site of the brush. He said the road building could wait but that the dam was needed at once. He hoped upon his return in three weeks to find Captain Miller's company at work on this Equalization Dam.