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72-746: The Pensacola Dam , also known as the Grand River Dam , is a multiple- arch buttress dam located between the towns of Disney and Langley on the Grand River in Mayes County , Oklahoma . The dam is operated by the Grand River Dam Authority and creates Grand Lake o' the Cherokees . After decades of vision and planning, it was constructed between 1938 and 1940 for the purposes of hydroelectric power generation, flood control and recreation. It

144-659: A Hertzian cone when struck with sufficient force. This results in conchoidal fractures, a characteristic of all minerals with no cleavage planes. In this kind of fracture, a cone of force propagates through the material from the point of impact, eventually removing a full or partial cone, like when a plate-glass window is struck by a small object such as an air gun projectile. The partial Hertzian cones produced during lithic reduction are called flakes , and exhibit features characteristic of this sort of breakage, including striking platforms , bulbs of force , and occasionally eraillures , which are small secondary flakes detached from

216-578: A better regulation of releases has been proposed while the GRDA is contemplating the installation of aeration devices and conducting studies along with other measures. The 1992 FERC license had addressed problematic DO levels and required the GRDA to plan methods to monitor and improve DO levels to a consistency with state water quality standards. In 2019-2020, residents of the town of Miami and neighboring Native American groups have objected to proposals to increase high water levels at Pensacola Dam and Grand Lake , on

288-467: A dam at the "Pensacola site" for flood control. The name "Pensacola" was derived from the only available means of identifying the site at the time: an old store on a Cherokee plantation. Because of limited state funding and a limited water supply on the Grand River, the project was not proposed at first for federal funding under the scope of hydroelectric power but instead for flood control. Oklahoma set up

360-448: A fraction of a micron to 20 microns, but most typically 8 to 10 microns. Chalcedony is a microfibrous variety of quartz, consisting of radiating bundles of very thin crystals about 100 microns long. Megaquartz is composed of equidimensional grains over 20 microns in size. Most chert is microcrystalline quartz with minor chalcedony and sometimes opal , but cherts range from nearly pure opal to nearly pure quartz chert. However, little opal

432-460: A generator was taken out of service, upgraded and returned to service by spring of the next year. The sixth and final generator upgrade was completed in May 2003. Among the components principally upgraded were the turbine shafts and runners . Pensacola Dam is a multiple-arch buttress type consisting of 51 arches and one main spillway , two auxiliary. It has a maximum height of 150 ft (46 m) above

504-413: A microcrystalline form of silica composed mostly of bladed crystals of cristobalite and tridymite . Much opal-CT takes the form of lepispheres , which are clusters of bladed crystals about 10 microns in diameter. Opal-CT in turn transforms to microquartz. In deep ocean water, the transition to opal-CT occurs at a temperature of about 45 °C (113 °F) while the transition to microquartz occurs at

576-479: A radius of 35 m (115 ft). Their second dam was built around 1350 and is called the Kurit Dam . After 4 m (13 ft) was added to the dam in 1850, it became 64 m (210 ft) tall and remained the tallest dam in the world until the early 20th century. The Kurit Dam was of masonry design and built in a very narrow canyon. The canyon was so narrow that its crest length is only 44% of its height. The dam

648-418: A source of dissolved silica, but they are sometimes found cutting across bedding surfaces, where the chert fills fossil burrows , fluid escape structures , or fractures. Nodules under a few centimeters in size tend to be egg-shaped, while larger nodules form irregular bodies with knobby surfaces. The outer few centimeters of large nodules may show desiccation cracks with secondary chert, which likely formed at

720-506: A spark that ignites a small reservoir containing black powder , discharging the firearm. Cherts can cause several problems when used as concrete aggregates. Deeply weathered chert develops surface pop-outs when used in concrete that undergoes freezing and thawing because of the high porosity of weathered chert. The other concern is that certain cherts undergo an alkali-silica reaction with high-alkali cements. This reaction leads to cracking and expansion of concrete and ultimately to failure of

792-870: A temperature of about 80 °C (176 °F). However, the transition temperature varies considerably, and the transition is hastened by the presence of magnesium hydroxide , which provides a nucleus for the recrystallization. Megaquartz forms at elevated temperatures typical of metamorphism . There is evidence that the variety of chert called porcelainite , which is characterized by a high content of opal-CT, recrystallizes at very shallow depths. The Caballos Novaculite of Texas also shows signs of very shallow water deposition, including shallow water sedimentary structures and evaporite pseudomorphs , which are casts of crystals of soluble minerals that could have formed only in near-surface conditions. This novaculate appears to have formed by replacement of carbonate fecal pellets by chert. Bedded cherts can be further subdivided by

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864-457: A week. Initial construction began in February 1938 and included the excavation of over 1,600,000 cu yd (1,200,000 m) of earth and rock. Workers also constructed the first cofferdam on the east side of the river and left it in place until the arches were above the normal water level. Once this was achieved, workers removed the east cofferdam and constructed another on the west side of

936-594: Is double-curved in both its horizontal and vertical planes may be called a dome dam . Arch dams with more than one contiguous arch or plane are described as multiple-arch dams . Early examples include the Roman Esparragalejo Dam with later examples such as the Daniel-Johnson Dam (1968) and Itaipu Dam (1982). However, as a result of the failure of the Gleno Dam shortly after it was constructed in 1923,

1008-495: Is 214 meters (702 ft) high and 1,314 meters (4,311 ft) long across its crest. It was completed in 1968 and put in service in 1970. Pensacola Dam was one of the last multiple arch types built in the United States. Its NRHP application states that this was because three dams of this type failed: (1) Gem Lake Dam, St. Francis Dam (California), Lake Hodges Dam (California). None of these failures were inherently caused by

1080-402: Is 742 ft (226 m) above sea level. The dam's power station is located at the base of the dam's western end and its building is 279 ft (85 m) long, 72 ft (22 m) wide and 60 ft (18 m) tall. The building houses six 20 MW Francis turbine generators that generate 335 million kWh annually and are each fed with their own individual penstock . The power plant

1152-502: Is Oklahoma's first hydroelectric power plant and is referred to as the longest multiple-arch dam in the world. The idea to construct a dam on the Grand River originated in the late 1800s with Henry C. Holderman, a Cherokee Nation citizen, who wanted to provide electric power to the Cherokee Nation. Holderman and a few colleagues soon conducted the first survey of the river in 1895 on their own handmade houseboat. Holderman later left

1224-448: Is characteristically of biological origin, but may also occur inorganically as a chemical precipitate or a diagenetic replacement, as in petrified wood . Chert is typically composed of the petrified remains of siliceous ooze , the biogenic sediment that covers large areas of the deep ocean floor, and which contains the silicon skeletal remains of diatoms , silicoflagellates , and radiolarians . Precambrian cherts are notable for

1296-564: Is designed to accommodate four additional generators. It operates at its highest generation levels during the summer and lowest during the winter. Just west of the power station is its substation and an observation house. The power station is regulated by the Federal Energy Regulatory Commission (FERC), under the Federal Power Act , with the current license issued in 1992 and set to expire in 2022. The first license

1368-418: Is far below saturation, indicating that silica cannot normally be precipitated from seawater through inorganic processes. The silica is instead extracted from seawater by living organisms, such as diatoms, radiolarians, and glass sponges, which can efficiently extract silica even from very unsaturated water, and which are estimated to presently produce 12 cubic kilometers (2.9 cu mi) of opal per year in

1440-885: Is little in the carbonate buildup zone itself. This may reflect dissolution of opal where carbonate is being actively deposited, a lack of siliceous organisms in these environments, or removal of siliceous skeletons by strong currents that redeposit the siliceous material in the deep basin. The silica in nodular chert likely precipitates as opal-A, based on internal banding in nodules, and may recrystallize directly to microquartz without first recrystallizing to opal-CT. Some nodular chert may precipitate directly as microquartz, due to low levels of supersaturation of silica. The banded iron formations of Precambrian age are composed of alternating layers of chert and iron oxides . Nonmarine cherts may form in saline alkaline lakes as thin lenses or nodules showing sedimentary structures suggestive of evaporite origin. Such cherts are forming today in

1512-403: Is made of concrete and placed in a V-shaped valley. The foundation or abutments for an arch dam must be very stable and proportionate to the concrete. There are two basic designs for an arch dam: constant-radius dams , which have constant radius of curvature, and variable-radius dams , which have both upstream and downstream curves that systematically decrease in radius below the crest. A dam that

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1584-485: Is of only modest economic importance today as a source of silica (quartz sand being much more important.) However, chert deposits may be associated with valuable deposits of iron , uranium , manganese , phosphorite , and petroleum . In prehistoric times, chert was often used as a raw material for the construction of stone tools . Like obsidian , as well as some rhyolites , felsites , quartzites , and other tool stones used in lithic reduction , chert fractures in

1656-512: Is over 60 million years old. Opaline chert often contains visible fossils of diatoms , radiolarians , and glass sponge spicules . Chert is found in settings as diverse as hot spring deposits ( siliceous sinter ), banded iron formation ( jaspilite ), or alkaline lakes . However, most chert is found either as bedded chert or as nodular chert . Bedded chert is more common in Precambrian beds, but nodular chert became more common in

1728-545: Is still erect, even though part of its lower downstream face fell off. The Tibi Dam in Tibi , Spain was a post-medieval arch dam built between 1579 and 1594 and the first in Europe since the Romans. The dam was 42.7 metres (140 ft) high and 65 metres (213 ft) long. This arch dam rests on the mountains sides. In the early 20th century, the world's first variable-radius arch dam

1800-435: Is the most abundant minor element, followed by iron and manganese or potassium , sodium , and calcium . Extracrystalline water (tiny inclusions of water within and around the quartz grains) make up less than 1% of most cherts. The Folk classification divides chert into three textural categories. Granular microquartz is the component of chert consisting of roughly equidimensional quartz grains, ranging in size from

1872-419: Is uncertain, but they may form from fossil remains that are completely dissolved in fluids that then migrate to precipitate their silica load in a nearby bed. Eolian quartz has also been suggested as a source of silica for chert beds. Precambrian bedded cherts are common, making up 15% of middle Precambrian sedimentary rock, and may have been deposited nonbiologically in oceans more saturated in silica than

1944-506: Is usually black to green in color, and the full sequence of beds may be several hundred meters thick. The shale is typically black shale, sometimes with pyrite , indicating deposition in an anoxic environment. Bedded chert is most often found in association with turbidites , deep water limestone , submarine volcanic rock , ophiolites , and mélanges on active margins of tectonic plates . Sedimentary structures are rare in bedded cherts. The typically high purity of bedded chert, like

2016-648: The Cretaceous . Diatoms were the dominant siliceous organism responsible for extracting silica from seawater from the Jurassic and later. Radiolarite consists mostly of remains of radiolarians. When the remains are well-cemented with silica, it is known as radiolarian chert . Many show evidence of a deep-water origin, but some appear to have formed in water as shallow as 200 meters (660 ft), perhaps in shelf seas where upwelling of nutrient-rich deep ocean water support high organic productivity. Radiolarians dominated

2088-589: The Phanerozoic as the total volume of chert in the rock record diminished. Bedded chert is rare after the early Mesozoic . Chert became moderately abundant during the Devonian and Carboniferous and again became moderately abundant from the Jurassic to the present. Bedded chert, also known as ribbon chert, takes the form of thinly bedded layers (a few centimeters to a meter in thickness ) of nearly pure chert separated by very thin layers of silica-rich shale . It

2160-702: The World War II effort and returned it to the GRDA in 1946. The construction of the Pensacola Dam resulted in the loss of 1,285 acres (520 ha) of Cherokee land and 802 acres (325 ha) of the Quapaw Indian Agency , most of which belonged to the Seneca-Cayuga Tribe . This land was condemned and later flooded by the reservoir in 1940. Half of the Seneca-Cayuga Elk River ceremonial area

2232-575: The 143-meter double-curved Morrow Point Dam in Colorado, completed in 1968. By the late 20th century, arch dam design reached a relative uniformity in design around the world. Currently, the tallest arch dam in the world is the 305 metres (1,001 ft) Jingpin-I Dam in China , which was completed in 2013. The longest multiple arch with buttress dam in the world is the Daniel-Johnson Dam in Quebec , Canada . It

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2304-518: The Grand River Dam Authority (GRDA) on January 10, 1935. Eventually, on September 18, 1937, with the help of Oklahoma Representative Wesley E. Disney , Senator Elmer Thomas and engineer W. R. Holway , President Franklin D. Roosevelt approved $ 20 million in funding through the New Deal 's Public Works Administration for the dam. The higher cost for the dam was attributed to a project that

2376-434: The Romans in 300 AD. It was 5.7 metres (19 ft) high and 52 m long (171 ft), with a radius of 19 m (62 ft). The curved ends of the dam met with two winged walls that were later supported by two buttresses. The dam also contained two water outlets to drive mills downstream. The Dara Dam was another arch dam built by the Romans in which the historian Procopius would write of its design: "This barrier

2448-453: The United States at the age of 16 and worked on dam projects in India and Africa before returning to Oklahoma. He sold his land holdings and borrowed money from friends in order to purchase rights to the dam sites he had prospected. Over several decades, Holderman and a group known as the "Rainbow Chasers" tried to secure funding to construct the dam; making several trips to Washington DC . The dam

2520-599: The Vallon de Baume Dam, was built by the Romans in France and it dates back to the 1st century BC. The dam was about 12 metres (39 ft) high and 18 metres (59 ft) in length. Its radius was about 14 m (46 ft), and it consisted of two masonry walls. The Romans built it to supply nearby Glanum with water. The Monte Novo Dam in Portugal was another early arch dam built by

2592-403: The alkaline Lake T'oo'dichi'. Chert may also form from replacement of calcrete in fossil soils ( paleosols ) by silica dissolved from overlying volcanic ash beds. The cryptocrystalline nature of chert, combined with its above average ability to resist weathering, recrystallization and metamorphism has made it an ideal rock for preservation of early life forms. For example: Chert

2664-538: The alkaline lakes of the East African Rift Valley . These lakes are characterized by sodium carbonate brines with very high pH that can contain as much as 2700 ppm silica. Episodes of runoff of fresh water into the lakes lowers the pH and precipitates the unusual sodium silicate minerals magadiite or kenyaite , After burial and diagenesis , these are altered to Magadi-type chert. The Morrison Formation contains Magadi-type chert that may have formed in

2736-616: The base to 2.2 ft (0.67 m) at the crest. Inside of each buttress are 18 in (460 mm) thick transverse walls that act as "stiffeners". The buttresses were the widest of their type prior to 1938 and are designed to withstand 500 lbf/in (3,400 kPa; 35 kgf/cm). The main spillway, part of the eastern end of the dam, is a 861 ft (262 m) long Ogee-type and utilizes twenty-one 25 ft (7.6 m) tall and 36 ft (11 m) wide tainter gates that are operated by two 60-ton hoists . The auxiliary spillways are located about 1 mi (1.6 km) northeast of

2808-422: The construction of new multiple arch dams has become less popular. Contraction joints are normally placed every 20 m in the arch dam and are later filled with grout after the control cools and cures. Chert Chert ( / tʃ ɜːr t / ) is a hard, fine-grained sedimentary rock composed of microcrystalline or cryptocrystalline quartz , the mineral form of silicon dioxide (SiO 2 ). Chert

2880-480: The dam and are controlled by another twenty-one 37 ft (11 m) wide and 15 ft (4.6 m) high tainter gates stretched over their combined 860 ft (260 m) length. The lip of the spillways lie at an elevation of 730 ft (220 m) above sea level while the tops of the gates are 755 ft (230 m). All three spillways have a combined maximum discharge of 525,000 cu ft/s (14,900 m/s). The two-lane State Highway 28 crosses over

2952-415: The dam has a clear span of 60 ft (18 m) and each buttress is 24 ft (7.3 m) wide. Arch dam designs would continue to test new limits and designs such as the double- and multiple-curve. Alfred Stucky and the U.S. Bureau of Reclamation developed a method of weight and stress distribution in the 1960s, and arch dam construction in the United States would see its last surge then with dams like

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3024-414: The dam have been the center of controversy in recent years. Since the dam is a multi-purpose project, there are conflicting interests between flood control, environmental conservation, recreation and hydroelectric power production. The USACE may request minimal releases to prevent flooding in areas downstream and in hot mid-summer periods, releases can be minimal. This reduces dissolved oxygen (DO) levels in

3096-477: The dam while also being instrumental in its legislation. Once approved and funded, Holway, the main engineer on the project and previous engineer of the nearby Spavinaw Dam , began survey and engineering work on October 25, 1937. The multiple-arch buttress design was adopted because materials were expensive at the time of the Great Depression and the limestone and chert foundation was considered "ideal" for

3168-406: The design. John Duncan Forsyth served as the architect for the dam and applied an Art Deco -style to it and the power house. Massman Construction Company out of Kansas City, Missouri was selected to construct the major superstructures , including the dam and power plant. Thousands of workers moved to the area to work on the dam before construction began and 3,000 eventually did, earning about $ 16

3240-553: The extraction of silica from seawater prior to the Jurassic. Spicularite is chert composed of spicules of glass sponges and other invertebrates. When densely cemented, it is known as spicular chert . They are found in association with glauconite -rich sandstone , black shale , clay -rich limestone , phosphorites , and other nonvolcanic rocks typical of water a few hundred meters deep. Some bedded cherts appear devoid of fossils even under close microscopic examination. Their origin

3312-419: The flake's bulb of force. When a chert stone is struck against an iron-bearing surface, sparks result. This makes chert an excellent tool for starting fires, and both flint and common chert were used in various types of fire-starting tools, such as tinderboxes , throughout history. A primary historic use of common chert and flint was for flintlock firearms , in which the chert striking a metal plate produces

3384-643: The grounds that when water backs up downstream, it can increase Miami's flooding problems. Between Memorial Day and Labor Day , the GRDA offers free tours of the dam. In 2010, there were over 9,000 visitors; a number which has been steadily growing in recent years. Additionally in 2010, the Ecosystems and Education Center was completed and has become part of the tour. The center serves as a water and fish monitoring research lab while offering visitors information about hydropower and water/electrical safety. Arch dam In general, arch dams are classified based on

3456-490: The high purity of other chemically precipitated rock, points to deposition in areas where there is little influx of detrital sediments (such as river water laden with silt and clay particles.) Such impurities as are present include authigenic pyrite and hematite, formed in the sediments after they were deposited, in addition to traces of detrital minerals. Seawater typically contains between 0.01 and 11 parts per million (ppm) of silica, with around 1 ppm being typical. This

3528-473: The kinds of organisms that produced the silica skeletons. Diatomaceous chert consists of beds and lenses of diatomite which were converted during diagenesis into dense, hard chert. Beds of marine diatomaceous chert comprising strata several hundred meters thick have been reported from sedimentary sequences such as the Miocene Monterey Formation of California and occur in rocks as old as

3600-606: The modern ocean. The high degree of silica saturation was due either to intense volcanic activity or to the lack of modern organisms that remove silica from seawater. Nodular chert is most common in limestone but may also be found in shales and sandstones. It is less common in dolomite . Nodular chert in carbonate rocks is found as oval to irregular nodules . These vary in size from powdery quartz particles to nodules several meters in size. The nodules are most typically along bedding planes or stylolite (dissolution) surfaces, where fossil organisms tended to accumulate and provided

3672-401: The multiple arch design. The design of an arch dam is a very complex process. It starts with an initial dam layout, that is continually improved until the design objectives are achieved within the design criteria. The main loads for which an arch dam is designed are: Other miscellaneous loads that affect a dam include: ice and silt loads, and uplift pressure. Most often, the arch dam

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3744-424: The ocean bottom and are buried, forming siliceous ooze that is 30% to 60% silica. Thus, bedded cherts are typically composed mostly of fossil remains of organisms that secrete silica skeletons, which are usually altered by solution and recrystallization. The skeletons of these organisms are composed of opal-A, an amorphous form of silica, lacking long-range crystal structure. This is gradually transformed to opal-CT,

3816-535: The presence of fossil cyanobacteria . In addition to microfossils , chert occasionally contains macrofossils . However, some chert is devoid of any fossils. Chert varies greatly in color, from white to black, but is most often found as gray, brown, grayish brown and light green to rusty red and occasionally as dark green. Its color is an expression of trace elements present in the rock. Both red and green are most often related to traces of iron in its oxidized and reduced forms, respectively. In petrology ,

3888-453: The ratio of the base thickness to the structural height (b/h) as: Arch dams classified with respect to their structural height are: The development of arch dams throughout history began with the Romans in the 1st century BC and after several designs and techniques were developed, relative uniformity was achieved in the 20th century. The first known arch dam, the Glanum Dam , also known as

3960-438: The river bed. The total length of the dam and its sections is 6,565 ft (2,001 m) while the multiple-arch section is 4,284 ft (1,306 m) long and its combination with the spillway sections measure 5,145 ft (1,568 m). Each arch in the dam has a clear span of 60 ft (18 m) and each buttress is 24 ft (7.3 m) wide. The thickness of the buttress sidewalls ranges from 5 ft (1.5 m) at

4032-456: The river downstream. Such reductions resulted in the death of at least 5,000 fish downstream in July 2007. Significant releases from the dam have drawn opposition from people such as Oklahoma State Representative Doug Cox. He argues that the large releases effect the state's economy as an off-road recreational rock park is flooded downstream. Inconsistent releases are blamed for the overall problem and

4104-405: The river to divert water from the location of the future power plant. On December 30, 1938, Massman began the first concrete pour. Pouring was conducted 24-hours a day for 20 months, totaling 510,000 cu yd (390,000 m). A total of 23.9 million pounds of steel and iron were placed into the dam's structure to reinforce it. Major works on the dam were complete on March 21, 1940 and the lake

4176-411: The same time as the nodule. Calcareous fossils are occasionally present that have been completely silicified. Where chert occurs in chalk or marl , it is usually called flint . Nodular chert is often dark in color. It can have a white weathering rind that is known in archaeology as cortex . Most chert nodules have textures suggesting they were formed by diagenetic replacement, where silica

4248-459: The state of Oklahoma in 1940, was considered the longest multiple arch dam in the United States. Designed by W. R. Holway , it has 51 arches. and a maximum height of 150 ft (46 m) above the river bed. The total length of the dam and its sections is 6,565 ft (2,001 m) while the multiple-arch section is 4,284 ft (1,306 m) long and its combination with the spillway sections measure 5,145 ft (1,568 m). Each arch in

4320-499: The state's economy but local energy providers opposed the possibility of a state-run electric utility . The onset of the Great Depression would revive and accelerate plans to construct the dam. Just prior in 1928, Oklahoma Representative Everette B. Howard secured $ 5,000 in funding for the U.S. Army Corps of Engineers to survey the Grand River. The results of the study concluded that it would cost over $ 6.2 million to construct

4392-468: The term "chert" refers generally to all chemically precipitated sedimentary rocks composed primarily of microcrystalline , cryptocrystalline and microfibrous silica . Most cherts are nearly pure silica, with less than 5% other minerals (mostly calcite , dolomite , clay minerals , hematite , and organic matter.) However, cherts range from very pure cherts with over 99% silica content to impure nodular cherts with less than 65% silica content. Aluminium

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4464-584: The top of the dam and a bridge that stretches over the main spillway. It is accessible by cars and trucks within weight. The dam's reservoir , Grand Lake o' the Cherokees (Grand Lake over the Cherokees), has a storage capacity of 1,672,000 acre⋅ft (2.062 × 10 m) of which 540,000 acre⋅ft (670,000,000 m) is flood storage. The reservoir's surface area is 46,500 acres (188 km) and it extends 66 mi (106 km) upstream, creating 1,300 mi (2,100 km) of shoreline. Normal surface elevation

4536-408: The world's oceans. Diatoms can double their numbers eight times a day under ideal conditions (though doubling once per day is more typical in normal seawater) and can extract silica from water with as little as 0.1 ppm silica. The organisms protect their skeletons from dissolution by "armoring" them with metal ions. Once the organisms die, their skeletons will quickly dissolve unless they accumulate on

4608-598: The world, in particular by the U.S. Bureau of Reclamation . In 1920, the Swiss engineer and dam designer Alfred Stucky developed new calculation methods for arch dams, introducing the concept of elasticity during the construction of the Montsalvens arch dam in Switzerland, thereby improving the dam profile in the vertical direction by using a parabolic arch shape instead of a circular arch shape. Pensacola Dam , completed in

4680-500: Was almost built in 1914 by British capitalists but plans were halted due to World War I . In 1920, Holderman refused an offer given by Chicago businessmen and in 1929, the Wall Street Crash ended the hopes of Canadian engineers and investors building the dam for Holderman. In DC, supporters of the dam, which later included state and federal officials, argued for the dam as a source of hydroelectric power and that it could stimulate

4752-502: Was approved for additional purposes, including hydroelectric power generation and recreation. Additional costs for the dam were covered by the state government and by GRDA municipal bond auctions which appropriated or raised $ 11 million. Disney had pushed much of the legislation for the dam, comparing the higher electric utility rates in Oklahoma compared to other states. Senator Thomas helped appropriate additional state and public funding for

4824-615: Was built on the Salmon Creek near Juneau , Alaska . The Salmon Creek Dam's upstream face bulged upstream, which relieved pressure on the stronger, curved lower arches near the abutments. The dam also had a larger toe, which off-set pressure on the upstream heel of the dam, which now curved more downstream. The technology and economical benefits of the Salmon Creek Dam allowed for larger and taller dam designs. The dam was, therefore, revolutionary, and similar designs were soon adopted around

4896-571: Was deposited in place of calcium carbonate or clay minerals . This may have taken place where meteoric water (water derived from snow or rain) mixed with saltwater in the sediment beds, where carbon dioxide was trapped, producing an environment supersaturated with silica and undersaturated with calcium carbonate. Nodular chert is particularly common in continental shelf environments. In the Permian Basin (North America) , chert nodules and chertified fossils are abundant in basin limestones, but there

4968-475: Was filled by the end of that year's summer. The dam's power plant, with four original hydroelectric generators, began commercial operation in 1941. The dam was finished in 26 months, ahead of schedule. Much of this was attributed to eastern Oklahoma having its 18 driest months on record during construction which alleviated obstacles from flooding. The federal government took control of the dam in November 1941 to aid in

5040-429: Was flooded as well. Although losing significant portions of land, some tribe members were forced to find work on the dam project. In the 1950s, two additional generators were added to the power station, bringing the total to six. Between 1995 and 2003, the dam's six hydroelectric generators were upgraded, bringing the installed capacity of the power plant from 92 MW to 120 MW and increasing its generation 20%. Each autumn,

5112-605: Was granted by the FERC's predecessor, the Federal Power Commission in 1939. When the reservoir's elevation exceeds 745 ft (227 m), control of the dam's discharges are transferred to the U.S. Army Corps of Engineers (USACE) who manage flood control in the larger basin. By federal regulation, the GRDA and the Corps of Engineers often coordinate discharges and reservoir levels. FERC and USACE regulated releases downstream from

5184-455: Was not built in a straight line, but was bent into the shape of a crescent, so that the curve, by lying against the current of the river, might be able to offer still more resistance to the force of the stream." The Mongols also built arch dams in modern-day Iran. Their earliest was the Kebar Dam built around 1300, which was 26 m (85 ft) high and 55 m (180 ft) long, and had

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