Groundwater, when pumped up from underneath the planet’s surface, is usually cheaper, easier to access and is less vulnerable to being polluted than water found on the earth’s surface. Because of this, it is normally used in public water supply chains. Groundwater is the largest single source of potable water storage in the USA. Underground aquifers possess much more water compared to the capacity of reservoirs and lakes, and this includes the Great Lakes. Some USA municipalities rely only on groundwater.
Professional hydrologists judge the estimated volume of underground water by taking water levels in locally sunk wells and by looking closely at the geologic record after well-drilling to help determine the breadth and depth of water-containing sediments, as well as rocks. Before a commitment is made to a full-sized well, hydrologists may require the drilling of a test well, or multiple test wells. They study the depths where water is found and inspect samples of soil, rocks and the water for lab analyses. They often perform a wide range of geophysical tests on the finished well, maintaining an accurate log of what they find and the test results. Hydrologists can then determine pumping efficiency rate by watching the degree to which water levels drop in the test well and others close by. Pumping too fast may cause it to dry up or interfere with other wells nearby. Near the coast, too much pumping can allow for saltwater intrusion. By analyzing the data, hydrologists can closely estimate the maximum, minimum and optimum output of the well.
Most cities meet their needs for water by withdrawing it from the nearest river, lake or reservoir. Hydrologists help cities by collecting and analyzing the data needed to predict how much water is available from local supplies and whether it will be sufficient to meet the city’s projected future needs. To do this, hydrologists study records of rainfall, snowpack depths and river flows that are collected and compiled by hydrologists in various government agencies. They inventory the extent river flow already is being used by others.
Managing reservoirs can be quite complex, because they generally serve many purposes. Reservoirs increase the reliability of local water supplies. Hydrologists use topographic maps and aerial photographs to determine where the reservoir shorelines will be and to calculate reservoir depths and storage capacity. This work ensures that, even at maximum capacity, no highways, railroads or homes would be flooded.
Deciding how much water to release and how much to store depends upon the time of year, flow predictions for the next several months, and the needs of irrigators and cities as well as downstream water-users that rely on the reservoir. If the reservoir also is used for recreation or for generation of hydroelectric power, those requirements must be considered. Decisions must be coordinated with other reservoir managers along the river. Hydrologists collect the necessary information, enter it into a computer, and run computer models to predict the results under various operating strategies. On the basis of these studies, reservoir managers can make the best decision for those involved.
The availability of surface water for swimming, drinking, industrial or other uses sometimes is restricted because of pollution. Pollution can be merely an unsightly and inconvenient nuisance, or it can be an invisible, but deadly, threat to the health of people, plants and animals.
Hydrologists assist public health officials in monitoring public water supplies to ensure that health standards are met. When pollution is discovered, environmental engineers work with hydrologists in devising the necessary sampling program. Water quality in estuaries, streams, rivers and lakes must be monitored, and the health of fish, plants and wildlife along their stretches surveyed. Related work concerns acid rain and its effects on aquatic life, and the behavior of toxic metals and organic chemicals in aquatic environments. Hydrologic and water quality mathematical models are developed and used by hydrologists for planning and management and predicting water quality effects of changed conditions. Simple analyses such as pH, turbidity, and oxygen content may be done by hydrologists in the field. Other chemical analyses require more sophisticated laboratory equipment. In the past, municipal and industrial sewage was a major source of pollution for streams and lakes. Such wastes often received only minimal treatment, or raw wastes were dumped into rivers. Today, we are more aware of the consequences of such actions, and billions of dollars must be invested in pollution-control equipment to protect the waters of the earth. Other sources of pollution are more difficult to identify and control. These include road deicing salts, storm runoff from urban areas and farmland, and erosion from construction sites.
When Hoover Dam was built in the 1930s, the great dam was known for its engineering superlatives. It was the highest dam ever built, the costliest water project, home of the largest power plant of its time.
Today, as Hoover celebrates its 60th anniversary, we can see that the dam is not only an engineering wonder. It also is a work of art.
Few structures in America display the diversity of design and craftsmanship that you see at Hoover Dam. It is a showcase of seldom-seen skills of artists and artisans–beautifully presented terrazzo tiles, sculpture, metalwork, and even military emplacements.
The dam’s architectural design varies a great deal from its initial plans. Bureau of Reclamation engineers, more concerned with flood control than appearance, simply wanted to embellish the dam with eagles, cornices, and other ornamentation.
The more streamlined look of the completed project was influenced by two men who were not engineers: architect Gordon B. Kaufmann, known for his design of the Los Angeles Times Building, and artist Allen True, whose murals are prominent in the Colorado State Capitol in Denver.
Kaufmann was a native of London, England, who lived in Southern California. He had been enlisted to help design the Administration Building in Boulder City, the federal town being built to house dam workers. After he was asked to comment on the aesthetics of the dam’s proposed design, Kaufmann became totally involved in the project. Richard Guy Wilson, architecture professor at the University of Virginia and a student of the dam, notes that the architect apparently was retained to counterbalance the engineers’ focus on “functionality rather than aesthetics.”
Kaufmann simplified the dam’s design and replaced ornamentation with the flowing lines of Modernism and Art Deco. The four areas where his influence is most visible are the power plant, dam crest, intake towers, and spillways. He transformed the power plant with color and facades. He blended four protruding towers on the crest into the face of the structure. He smoothed the upper portions of the four intake towers and reworked the two spillways to accent Art Deco elements.
“There was never any desire or attempt to create an architectural effect or style,” he later explained, “but rather to take each problem and integrate it to the whole in order to secure a system of plain surfaces relieved by shadows here and there.” The architect later produced progressively simplified designs for downstream Parker Dam and for Shasta Dam in Northern California.
Allen True, the Denver artist, assisted Kaufmann with interior designs and color. True was responsible for one of the dam’s most distinctive motifs–the Southwestern Indian designs in the terrazzo floors. Using such sources as an Acoma bowl and Pima basket, True linked Native American geometric concepts with Art Deco design. Many of the Indian designs were based on centrifugal themes, which related to the turbines in the power plant.
True’s colors were truly striking. He used black, white, green and dull-red ochre chips in the terrazzo floors to contrast with the black-marble walls. True also specified the red color for the generator shells in the power plant, a sight that still commands visitors’ attention.
You can see the power plant and terrazzo work during a tour of the dam. Following an elevator descent of 530 feet, you emerge into seemingly endless galleries. There you find gleaming terrazzo floors imbedded with the Southwestern Indian patterns adapted by True from baskets, pottery, and sand paintings.
Two Italian immigrant brothers, Joseph and John Martina, installed the terrazzo floors in 1936-37 with the help of 30 countrymen. John served as contractor for the job and worked with Reclamation officials. Joe, barely able to speak English when they bid on the job, was in charge of laying the floors. The Martina brothers contracted to install the terrazzo for 48 cents per square foot, for a total of only $51,718. Costs today would exceed $20 per square foot.
To create the terrazzo, the workers imbedded marble chips in cement, separating them with brass or aluminum divider strips to make a tiled pattern. After the mosaic hardened, they used large finishing machines to polish the surfaces. The result was a lustrous terrazzo.
On top of the dam, two “Winged Figures of the Republic” dominate the Nevada approach, They are the work of sculptor Oskar J.W. Hansen, a Norwegian immigrant who was appointed a consulting sculptor by Secretary of the Interior Harold L. Ickes following a national competition.
Hansen said the 30-foot bronzed statues represented “that eternal vigilance which is the price of liberty.” Perched on six-foot-tall cues of gleaming black diorite, Hansen’s figures flank a 142-foot flagpole. In front of this array he placed a terrazzo star map depicting the celestial alignment from that site on the evening of September 30, 1935, the day President Franklin D. Roosevelt dedicated what was then called Boulder Dam.
Hansen also created the nearby bronze plaque memorializing the 96 workers who died during construction of the dam. An inscription proclaims, “They died to make the desert bloom.”
You can see more of Hansen’s work on the two elevator towers. Each displays five bas-reliefs that tell a story. The Arizona tower has a tribute to Native American tribes and their Great Spirit of the ranges and the plains. The five Nevada panels portray the dam’s main purposes — flood control, navigation, irrigation, water storage, and power.
Away from the tour route, and off-limits to the public, are two unique forms of craftsmanship that appeared after the dam’s completion in 1935. The first is found in the power plant’s “gold room,” where solid-copper cabinetry surrounds heavy copper bars carrying electricity from generators to transformers. Fred Johnson, electrical engineer at Hoover Dam, says the name “gold room” probably derived from the bright finishes of the copper cabinets, but rumors persist that the metal has a high gold content.
The other curiosity stands above the dam. If you look on the Arizona (eastern) side of Lake Mead, you will see a cubical silhouette. This is a gun emplacement built during World War II. As a major source of electrical power for the defense industry, Hoover Dam was considered a primary military target. Of several bunkers that guarded the dam in wartime, this one is the last survivor.
The pillbox, constructed of steel and concrete and veneered with local rock, is 24 feet long and has six gun ports. It was built by a military police battalion soon after the attack on Pearl Harbor, according to Lincoln Clark of Las Vegas. A retired U.S. Army lieutenant colonel, Clark was a first lieutenant when stationed at the dam in 1942. He and his fellow soldiers guarded the dam and escorted civilian vehicles across it. One soldier was always inside in the bunker, Clark recalls, and a squad of riflemen was scattered in the rocks 24 hours a day.
Thus the soldiers demonstrated the “eternal vigilance” that Oskar Hansen sought to portray in his handsome winged figures, seen by all who cross the dam.
Hansen, an intensely creative sculptor, showed his sense of humor one day at the dam. While he was working on the sculptures, a woman asked him how he began such an endeavor. “Madam,” Hansen replied, “when you peel an orange, do you begin by sticking your thumb into its center?” He meant that a sculptor must take all parts of a work into consideration before “peeling” away the unused material.
Today we can admire the way Hansen and other artists and craftsmen peeled away Hoover Dam to create a structure of beauty as well as utility.
Dry Fork of Roan Creek, station 09095300, was chosen as a reference site for the Colorado Plateau physiographic province. There is a small amount of ranching in the basin, but the site is representative of small streams in the region. This site was operated during the HIP of 1996-1998 and was reestablished in November 2000 as part of the surface water trends network.
The Bureau of Reclamation’s Upper Colorado and Lower Colorado Regions, in collaboration with representatives of the seven Colorado River Basin States submitted a Proposal in June 2009 to fund the “Colorado River Basin Water Supply and Demand Study” under Reclamation’s Basin Study Program. In September 2009, the Study was selected for funding.
The Study, which began in January 2010, was completed in December 2012. It defined current and future imbalances in water supply and demand in the Colorado River Basin and the adjacent areas of the Basin States that receive Colorado River water for approximately the next 50 years, and developed and analyzed adaptation and mitigation strategies to resolve those imbalances.
The Study characterized current and future water supply and demand imbalances in the Basin and assessed the risks to Basin resources. Resources include water allocations and deliveries consistent with the apportionments under the Law of the River; hydroelectric power generation; recreation; fish, wildlife, and their habitats (including candidate, threatened, and endangered species); water quality including salinity; flow- and water-dependent ecological systems; and flood control.
The Study confirmed what most experts know: there are likely to be significant shortfalls between projected water supplies and demands in the Colorado River Basin in the coming decades. Following the call to action of the Study, all that rely on the Colorado are taking initial steps – working together – to identify positive solutions that can be implemented to meet the challenges ahead.
The Colorado River is one of the most extensively managed bodies of water in the United States. Serving an estimated 30 million people and an area with roughly 3.5 million acres of farmland, most of it irrigated, the use of water in the River is controlled by a complex collection of laws, court decisions, interstate compacts and regulations. This body of documents is known collectively as the “Law of the River.”
Major elements of the Law of the River include:
● The Colorado River Compact of 1922, the interstate agreement, ratified by the federal government, that divided the rights to water in the river between the Upper Basin states of Wyoming, Colorado, Utah and New Mexico and the Lower Basin states of Arizona, Nevada and California.
● The Boulder Canyon Project Act of 1928, which not only authorized the construction of Hoover Dam, but also apportioned the water available to the Lower Basin among the three states involved.
● The Arizona v. California US Supreme Court Decision of 1964, which finally settled a 25-year dispute between the two states over their competing claims to the River. The decision also perfected the legal rights of five Colorado River tribes to their share of the water.
● The Colorado River Basin Project Act of 1968, which authorized the construction of the Central Arizona Project.
● Treaty agreements between the United States and Mexico providing for Mexico’s rights to a share of the water in the River.