A dam is a barrier that stops or restricts the flow of water or underground streams. Reservoirs created by dams not only suppress floods but provide water for activities such as irrigation, human consumption, industrial use and navigability. Hydropower is used in conjunction with dams to generate electricity. A dam can be used to collect water or for storage of water which can be evenly distributed between locations. Dams serve the primary purpose of retaining water, while other structures such as floodgates or levees are used to manage or prevent water flow into specific land regions; the earliest known dam is the Jawa Dam in Jordan, dating to 3,000 BC. The word dam can be traced back to Middle English, before that, from Middle Dutch, as seen in the names of many old cities; the first known appearance of dam occurs in 1165. However, there is one village, mentioned in 1120; the word seems to be related to the Greek word taphos, meaning "grave" or "grave hill". So the word should be understood as "dike from dug out earth".
The names of more than 40 places from the Middle Dutch era such as Amsterdam and Rotterdam bear testimony to the use of the word in Middle Dutch at that time. Early dam building took place in the Middle East. Dams were used to control the water level, for Mesopotamia's weather affected the Tigris and Euphrates rivers; the earliest known dam is the Jawa Dam in Jordan, 100 kilometres northeast of the capital Amman. This gravity dam featured an 9-metre-high and 1 m-wide stone wall, supported by a 50 m-wide earth rampart; the structure is dated to 3000 BC. The Ancient Egyptian Sadd-el-Kafara Dam at Wadi Al-Garawi, located about 25 km south of Cairo, was 102 m long at its base and 87 m wide; the structure was built around 2800 or 2600 BC as a diversion dam for flood control, but was destroyed by heavy rain during construction or shortly afterwards. During the Twelfth Dynasty in the 19th century BC, the Pharaohs Senosert III, Amenemhat III and Amenemhat IV dug a canal 16 km long linking the Fayum Depression to the Nile in Middle Egypt.
Two dams called Ha-Uar running east-west were built to retain water during the annual flood and release it to surrounding lands. The lake called "Mer-wer" or Lake Moeris is known today as Birket Qarun. By the mid-late third millennium BC, an intricate water-management system within Dholavira in modern-day India was built; the system included 16 reservoirs and various channels for collecting water and storing it. One of the engineering wonders of the ancient world was the Great Dam of Marib in Yemen. Initiated somewhere between 1750 and 1700 BC, it was made of packed earth – triangular in cross section, 580 m in length and 4 m high – running between two groups of rocks on either side, to which it was linked by substantial stonework. Repairs were carried out during various periods, most important around 750 BC, 250 years the dam height was increased to 7 m. After the end of the Kingdom of Saba, the dam fell under the control of the Ḥimyarites who undertook further improvements, creating a structure 14 m high, with five spillway channels, two masonry-reinforced sluices, a settling pond, a 1,000 m canal to a distribution tank.
These extensive works were not finalized until 325 AD and allowed the irrigation of 25,000 acres. Eflatun Pınar is a Hittite spring temple near Konya, Turkey, it is thought to be from the time of the Hittite empire between the 15th and 13th century BC. The Kallanai is constructed of unhewn stone, over 300 m long, 4.5 m high and 20 m wide, across the main stream of the Kaveri river in Tamil Nadu, South India. The basic structure dates to the 2nd century AD and is considered one of the oldest water-diversion or water-regulator structures in the world, still in use; the purpose of the dam was to divert the waters of the Kaveri across the fertile delta region for irrigation via canals. Du Jiang Yan is the oldest surviving irrigation system in China that included a dam that directed waterflow, it was finished in 251 BC. A large earthen dam, made by Sunshu Ao, the prime minister of Chu, flooded a valley in modern-day northern Anhui province that created an enormous irrigation reservoir, a reservoir, still present today.
Roman dam construction was characterized by "the Romans' ability to plan and organize engineering construction on a grand scale." Roman planners introduced the then-novel concept of large reservoir dams which could secure a permanent water supply for urban settlements over the dry season. Their pioneering use of water-proof hydraulic mortar and Roman concrete allowed for much larger dam structures than built, such as the Lake Homs Dam the largest water barrier to that date, the Harbaqa Dam, both in Roman Syria; the highest Roman dam was the Subiaco Dam near Rome. Roman engineers made routine use of ancient standard designs like embankment dams and masonry gravity dams. Apart from that, they displayed a high degree of inventiveness, introducing most of the other basic dam designs, unknown until then; these include arch-gravity dams, arch dams, buttress dams and multiple arch buttress dams, all of which were known and employed by the 2nd century AD. Roman workforces were the first to build dam bridges, such as the Bridge of Valerian in Iran
Glenwood Canyon is a rugged scenic 12.5 mi canyon on the Colorado River in western Colorado in the United States. Its walls climb as high as 1,300 feet above the Colorado River, it is the largest such canyon on the Upper Colorado. The canyon, which has provided the routes of railroads and highways through western Colorado furnishes the routes of Interstate 70 and the Central Corridor between Denver and Grand Junction; the canyon stretches from near Dotsero, where the Colorado receives the Eagle River, downstream in a west-southwest direction to just east of Glenwood Springs, on the mouth of the Roaring Fork. Most of the canyon is with the upper portion near Dotsero lying in Eagle County. In 1906, the canyon provided the route of the Taylor State Road, a gravel road, the first route for automobiles through the Colorado Rockies; the canyon provided the route for the Denver and Rio Grande Western Railroad in the late 19th century. Through acquisitions, the line is part of the Union Pacific system.
As Glenwood Canyon was one of the iconic scenic views along the California Zephyr passenger train, a monument to the dome car design was installed in the canyon. In the 1990s, the monument was relocated to the Colorado Railroad Museum in Golden to make way for the construction on Interstate 70; the canyon is considered one of the most scenic natural features on the Interstate Highway System of the United States. Foot access to the canyon is available at four rest areas along Interstate 70 in the canyon; the Hanging Lake Rest Area provides access to the canyon along a stretch where I-70 is concealed in the Hanging Lake Tunnel. The freeway is prone to rockslides in the canyon, such as the one that closed it in February 2016; the canyon was formed recently in Pleistocene time by the rapid cutting of the Colorado down through layers of sedimentary rock. The upper layers of the canyon are sandstone from Mississippian. Sections of the lower canyon walls are made of Cambrian rock; the Mississippian layer, prominent throughout much of the upper rim sections of the canyon is part of the Leadville Formation.
Gore Canyon Roadside Geology of Colorado by Halka Chronic. Glenwood Canyon I70 motorway project 12 years later
Colorado is a state of the Western United States encompassing most of the southern Rocky Mountains as well as the northeastern portion of the Colorado Plateau and the western edge of the Great Plains. It is the 8th most extensive and 21st most populous U. S. state. The estimated population of Colorado was 5,695,564 on July 1, 2018, an increase of 13.25% since the 2010 United States Census. The state was named for the Colorado River, which early Spanish explorers named the Río Colorado for the ruddy silt the river carried from the mountains; the Territory of Colorado was organized on February 28, 1861, on August 1, 1876, U. S. President Ulysses S. Grant signed Proclamation 230 admitting Colorado to the Union as the 38th state. Colorado is nicknamed the "Centennial State" because it became a state one century after the signing of the United States Declaration of Independence. Colorado is bordered by Wyoming to the north, Nebraska to the northeast, Kansas to the east, Oklahoma to the southeast, New Mexico to the south, Utah to the west, touches Arizona to the southwest at the Four Corners.
Colorado is noted for its vivid landscape of mountains, high plains, canyons, plateaus and desert lands. Colorado is part of the western and southwestern United States, is one of the Mountain States. Denver is most populous city of Colorado. Residents of the state are known as Coloradans, although the antiquated term "Coloradoan" is used. Colorado is notable for its diverse geography, which includes alpine mountains, high plains, deserts with huge sand dunes, deep canyons. In 1861, the United States Congress defined the boundaries of the new Territory of Colorado by lines of latitude and longitude, stretching from 37°N to 41°N latitude, from 102°02'48"W to 109°02'48"W longitude. After 158 years of government surveys, the borders of Colorado are now defined by 697 boundary markers and 697 straight boundary lines. Colorado and Utah are the only states that have their borders defined by straight boundary lines with no natural features; the southwest corner of Colorado is the Four Corners Monument at 36°59'56"N, 109°2'43"W.
This is the only place in the United States where four states meet: Colorado, New Mexico and Utah. The summit of Mount Elbert at 14,440 feet elevation in Lake County is the highest point in Colorado and the Rocky Mountains of North America. Colorado is the only U. S. state that lies above 1,000 meters elevation. The point where the Arikaree River flows out of Yuma County and into Cheyenne County, Kansas, is the lowest point in Colorado at 3,317 feet elevation; this point, which holds the distinction of being the highest low elevation point of any state, is higher than the high elevation points of 18 states and the District of Columbia. A little less than half of Colorado is flat and rolling land. East of the Rocky Mountains are the Colorado Eastern Plains of the High Plains, the section of the Great Plains within Nebraska at elevations ranging from 3,350 to 7,500 feet; the Colorado plains are prairies but include deciduous forests and canyons. Precipitation averages 15 to 25 inches annually. Eastern Colorado is presently farmland and rangeland, along with small farming villages and towns.
Corn, hay and oats are all typical crops. Most villages and towns in this region boast both a grain elevator. Irrigation water is available from subterranean sources. Surface water sources include the South Platte, the Arkansas River, a few other streams. Subterranean water is accessed through artesian wells. Heavy use of wells for irrigation caused underground water reserves to decline. Eastern Colorado hosts considerable livestock, such as hog farms. 70% of Colorado's population resides along the eastern edge of the Rocky Mountains in the Front Range Urban Corridor between Cheyenne and Pueblo, Colorado. This region is protected from prevailing storms that blow in from the Pacific Ocean region by the high Rockies in the middle of Colorado; the "Front Range" includes Denver, Fort Collins, Castle Rock, Colorado Springs, Pueblo and other townships and municipalities in between. On the other side of the Rockies, the significant population centers in Western Colorado are the cities of Grand Junction and Montrose.
The Continental Divide of the Americas extends along the crest of the Rocky Mountains. The area of Colorado to the west of the Continental Divide is called the Western Slope of Colorado. West of the Continental Divide, water flows to the southwest via the Colorado River and the Green River into the Gulf of California. Within the interior of the Rocky Mountains are several large parks which are high broad basins. In the north, on the east side of the Continental Divide is the North Park of Colorado; the North Park is drained by the North Platte River, which flows north into Nebraska. Just to the south of North Park, but on the western side of the Continental Divide, is the Middle Park of Colorado, drained by the Colorado River; the South Park of Colorado is the region of the headwaters of the South Platte River. In southmost Colorado is the large San Luis Valley, where the headwaters of the Rio Grande are located; the valley sits between the Sangre De Cristo Mountains and San Juan Mountains, consists of large desert lands that run into the mountains.
The Rio Grande drains due south into New Mexico and Texas. Across the Sangre de Cristo Range to the east of the S
The Grand Canyon is a steep-sided canyon carved by the Colorado River in Arizona, United States. The Grand Canyon is 277 miles long, up to 18 miles wide and attains a depth of over a mile; the canyon and adjacent rim are contained within Grand Canyon National Park, the Kaibab National Forest, Grand Canyon-Parashant National Monument, the Hualapai Indian Reservation, the Havasupai Indian Reservation and the Navajo Nation. President Theodore Roosevelt was a major proponent of preservation of the Grand Canyon area, visited it on numerous occasions to hunt and enjoy the scenery. Nearly two billion years of Earth's geological history have been exposed as the Colorado River and its tributaries cut their channels through layer after layer of rock while the Colorado Plateau was uplifted. While some aspects about the history of incision of the canyon are debated by geologists, several recent studies support the hypothesis that the Colorado River established its course through the area about 5 to 6 million years ago.
Since that time, the Colorado River has driven the down-cutting of the tributaries and retreat of the cliffs deepening and widening the canyon. For thousands of years, the area has been continuously inhabited by Native Americans, who built settlements within the canyon and its many caves; the Pueblo people considered the Grand Canyon a holy site, made pilgrimages to it. The first European known to have viewed the Grand Canyon was García López de Cárdenas from Spain, who arrived in 1540; the Grand Canyon is a river valley in the Colorado Plateau that exposes uplifted Proterozoic and Paleozoic strata, is one of the six distinct physiographic sections of the Colorado Plateau province. It is not the deepest canyon in the world. However, the Grand Canyon is known for its visually overwhelming size and its intricate and colorful landscape. Geologically, it is significant because of the thick sequence of ancient rocks that are well preserved and exposed in the walls of the canyon; these rock layers record much of the early geologic history of the North American continent.
Uplift associated with mountain formation moved these sediments thousands of feet upward and created the Colorado Plateau. The higher elevation has resulted in greater precipitation in the Colorado River drainage area, but not enough to change the Grand Canyon area from being semi-arid; the uplift of the Colorado Plateau is uneven, the Kaibab Plateau that Grand Canyon bisects is over one thousand feet higher at the North Rim than at the South Rim. All runoff from the North Rim flows toward the Grand Canyon, while much of the runoff on the plateau behind the South Rim flows away from the canyon; the result is deeper and longer tributary washes and canyons on the north side and shorter and steeper side canyons on the south side. Temperatures on the North Rim are lower than those on the South Rim because of the greater elevation. Heavy rains are common on both rims during the summer months. Access to the North Rim via the primary route leading to the canyon is limited during the winter season due to road closures.
The Grand Canyon is part of the Colorado River basin which has developed over the past 70 million years, in part based on apatite /He thermochronometry showing that Grand Canyon reached a depth near to the modern depth by 20 Ma. A recent study examining caves near Grand Canyon places their origins beginning about 17 million years ago. Previous estimates had placed the age of the canyon at 5–6 million years; the study, published in the journal Science in 2008, used uranium-lead dating to analyze calcite deposits found on the walls of nine caves throughout the canyon. There is a substantial amount of controversy because this research suggests such a substantial departure from prior supported scientific consensus. In December 2012, a study published in the journal Science claimed new tests had suggested the Grand Canyon could be as old as 70 million years. However, this study has been criticized by those who support the "young canyon" age of around six million years as " attempt to push the interpretation of their new data to their limits without consideration of the whole range of other geologic data sets."The canyon is the result of erosion which exposes one of the most complete geologic columns on the planet.
The major geologic exposures in the Grand Canyon range in age from the 2-billion-year-old Vishnu Schist at the bottom of the Inner Gorge to the 230-million-year-old Kaibab Limestone on the Rim. There is a gap of about a billion years between the 500-million-year-old stratum and the level below it, which dates to about 1.5 billion years ago. This large unconformity indicates a long period. Many of the formations were deposited in warm shallow seas, near-shore environments, swamps as the seashore advanced and retreated over the edge of a proto-North America. Major exceptions include the Permian Coconino Sandstone, which contains abundant geological evidence of aeolian sand dune deposition. Several parts of the Supai Group were deposited in non–marine environments; the great depth of the Grand Canyon and the height of its strata can be attributed to 5–10 thousand feet of uplift of the Colorado Plateau, starting about 65 million years ago. This uplift has steepened the stream gradient of the Colorado River
An embankment dam is a large artificial dam. It is created by the placement and compaction of a complex semi-plastic mound of various compositions of soil, clay, or rock, it has a semi-pervious waterproof natural covering for a dense, impervious core. This makes such a dam impervious to seepage erosion; such a dam is composed of fragmented independent material particles. The friction and interaction of particles binds the particles together into a stable mass rather than by the use of a cementing substance. Embankment dams come in two types: the earth-filled dam made of compacted earth, the rock-filled dam. A cross-section of an embankment dam shows a shape like hill. Most have a central section or core composed of an impermeable material to stop water from seeping through the dam; the core can be of concrete, or asphalt concrete. This dam type is a good choice for sites with wide valleys, they can be built on softer soils. For a rock-fill dam, rock-fill is blasted using explosives to break the rock.
Additionally, the rock pieces may need to be crushed into smaller grades to get the right range of size for use in an embankment dam. The building of a dam and the filling of the reservoir behind it places a new weight on the floor and sides of a valley; the stress of the water increases linearly with its depth. Water pushes against the upstream face of the dam, a nonrigid structure that under stress behaves semiplastically, causes greater need for adjustment near the base of the dam than at shallower water levels, thus the stress level of the dam must be calculated in advance of building to ensure that its break level threshold is not exceeded. Overtopping or overflow of an embankment dam beyond its spillway capacity will cause its eventual failure; the erosion of the dam's material by overtopping runoff will remove masses of material whose weight holds the dam in place and against the hydraulic forces acting to move the dam. A small sustained overtopping flow can remove thousands of tons of overburden soil from the mass of the dam within hours.
The removal of this mass unbalances the forces that stabilize the dam against its reservoir as the mass of water still impounded behind the dam presses against the lightened mass of the embankment, made lighter by surface erosion. As the mass of the dam erodes, the force exerted by the reservoir begins to move the entire structure; the embankment, having no elastic strength, would begin to break into separate pieces, allowing the impounded reservoir water to flow between them and removing more material as it passes through. In the final stages of failure the remaining pieces of the embankment would offer no resistance to the flow of the water and continue to fracture into smaller and smaller sections of earth or rock until these would disintegrate into a thick mud soup of earth and water. Therefore, safety requirements for the spillway are high, require it to be capable of containing a maximum flood stage, it is common for its specifications to be written such. A number of embankment dam overtopping protection systems have been developed.
These techniques include the concrete overtopping protection systems, timber cribs, sheet-piles and gabions, reinforced earth, minimum energy loss weirs, embankment overflow stepped spillways and the precast concrete block protection systems. Earth structure Gravity dam List of largest dams in the world Embankment dams Table of contents An introduction to embankment dams 100 Years of Embankment Dam Design and Construction in the U. S. Bureau of Reclamation
Colorado-Big Thompson Project
The Colorado-Big Thompson Project is a federal water diversion project in Colorado designed to collect West Slope mountain water from the headwaters of the Colorado River and divert it to Colorado's Front Range and plains. In Colorado 80% of the state's precipitation falls on the West Slope, in the Rocky Mountains, while around 80% of the state's growing population lives along the East Slope, between the cities of Fort Collins and Pueblo. Ten reservoirs, about 18 dams and dikes, the Alva B. Adams Tunnel under the Continental Divide, as well as six power plants, make up the project; the C-BT is owned and managed by the U. S. Bureau of Reclamation's Eastern Colorado Area Office under its Great Plains Region; the project was built, is owned, is operated by the federal Bureau of Reclamation under the Department of the Interior. By the late 1890s, farmers in northeastern Colorado realized water rights in the area had become over-appropriated. In order to survive the agricultural season, additional water supplies would be needed.
Prior to the Dust Bowl era, agriculture in this section of the state had relied upon sources such as Boulder Creek, St. Vrain Creek, Little Thompson River, Big Thompson River and the Cache La Poudre River, all of which are a part of the South Platte River basin and flow into the South Platte River before the South Platte reaches Greeley, Colorado. In search of a solution and their representatives approached the Bureau of Reclamation. In the late 1930s a solution was found: divert the water via a 13.2-mile -long tunnel under the Continental Divide and Rocky Mountain National Park. The proposed water diversion was extensive and the project could not have been constructed without compensation to the West Slope for the water sent East; as a result, the first feature built on the C-BT was Green Mountain Dam and Reservoir, a West Slope facility designed to provide for future water demands in the state's Upper Colorado River Basin. The project was authorized by President Franklin Delano Roosevelt in 1937.
Construction began on Green Mountain in the northern part of Summit County in 1938. Construction on the project continued through most of the next 20 years. While the project was built for agricultural purposes, it serves multiple demands including municipal and industrial supply, hydro-power generation and fish and wildlife. In recent years, water supply demands have shifted making municipal and industrial supply the main water beneficiary, rather than irrigation. Today, the "C-BT" serves over 33 cities and towns in northeastern Colorado, including Fort Collins, Loveland, Estes Park and Sterling, encompassed by 7 counties, providing a secondary source of water for around 830,000 people and an irrigated area of 650,000 acres. Although water rights allow for up to 310,000 acre feet of water a year to be diverted, annual diversions average around 220,000 acre feet, instead. A drop of over 2000 vertical feet from the Rockies down to the plains allows for power generation. Six power plants on the project produce an average supply of 759 million kilowatt hours of electricity a year.
Like the water supply, generated electricity is supplemental. Electricity produced on the C-BT is a source of "peaking power" and is marketed by the Department of Energy via its Western Area Power Administration. An extensive series of reservoirs and conduits on the west side of the Rockies serve to collect water from the headwaters of the Colorado River, as well as two tributaries, Cottonwood Creek and the Fraser River. Lake Granby, located in eastern Grand County, is the primary C-BT storage facility, with a capacity of 539,800 acre feet; the reservoir is held by 12,722 feet of auxiliary dikes. Willow Creek Reservoir is built on Willow Creek, located west of Lake Granby, provides a source from which water is diverted and pumped to Granby. Windy Gap Reservoir is a small diversion facility located directly below the confluence of the Colorado and Fraser rivers, about 5 miles downstream of Granby. Water from the Fraser River, as well as other inflows to the Colorado below Granby Dam, is diverted here and pumped eastwards to Lake Granby.
The Windy Gap project is not owned by the Bureau of Reclamation, but by the Northern Water Municipal District, a consortium of six Front Range cities. However, Windy Gap water uses the storage and distribution facilities of the Bureau of Reclamation's C-BT. From Lake Granby the water is lifted 125 feet up to Shadow Mountain Lake, located on the Colorado River west of the natural Grand Lake; the two bodies of water are connected by a short channel which allows water to flow to the intake of the Alva B. Adams Tunnel on Grand Lake's eastern shore; the water flows 13.2 miles under the Continental Divide through the Adams Tunnel, which can carry up to 550 cubic feet per second to the Eastern Slope. Once the water emerges from the Adams Tunnel just southwest of Estes Park, the system is entirely gravity powered, dropping some 2,800 feet as it descends to the foothills of the Rocky Mountains west of Loveland; the tunnel outlet is located at a small regulating pool on the Wind River. From here it is transported via an inverted siphon across the Aspen Creek valley and drops 205 feet to Marys Lake, where it drives the 8.1 megawatt Marys Lake Powerplant.
Marys Lake is a small natural lake enlarged to form a second regulatory reservoir. The water drops 515 feet to the 45-MW Estes Powerplant at Lake Estes, f
Glen Canyon is a natural canyon in southeastern and south-central Utah. A small part of the lower end of Glen Canyon extends into the northern part of Arizona and terminates at the Vermilion Cliffs area in the United States. Like the Grand Canyon to the south, Glen Canyon is part of the immense system of canyons carved by the Colorado River and its tributaries. In 1963, a reservoir, Lake Powell, was created by the construction of the Glen Canyon Dam, in the Arizona portion of Glen Canyon; this dam backed water into Utah. Lake Powell was not the result of negotiations over the controversial damming of the Green River within Dinosaur National Monument at Echo Park; the Echo Park Dam proposal was abandoned due to country wide citizen pressure on Congress to do so. Glen Canyon dam remains a central issue for modern environmentalist movements. Beginning in the late 1990s, the Sierra Club and other organizations renewed the call to dismantle the dam and drain Lake Powell in Lower Glen Canyon. Today, Glen Canyon and Lake Powell are managed by the U.
S. Department of the Interior within Glen Canyon National Recreation Area. Around 1956, archaeologists and biologists from the University of Utah and the Museum of Northern Arizona, using National Park research grants, planned an emergency excavation of Lower Glen Canyon, soon to be flooded by the new Glen Canyon Dam. Between 1958 and 1960, four investigative phases, combined with other surveys prior to 1957, discovered 250 archaeological sites within the canyon; the Lower Glen Canyon survey was completed in 1958. Excavations began during the summer of 1958 on 16 sites. A thesis emerged that prehistoric people living permanently on the highlands south of Glen Canyon, on the Cummings Mesa, farmed the Lower Glen Canyon on a seasonal basis, gathered raw materials. To prove this thesis of seasonal habitation, criteria such as architectural units, locations of trail systems, occurrence of ceremonial structures, prevalence of burials, position of natural and cultural strata. Four types of sites are described in the survey classified as either open sites situated on rock terraces.
Open sites are the majority on both sides of the river. The majority of sites Navajo camps, feature lithic garbage or ceramics, or both. Talus sites are recorded. Most of the cultural remains found are chipped stone tools, including projectile points, drills, knives and ground stone tools and manos; the collection of sherds are Tusayan Gray Ware and Tusayan White Ware. Petroglyph panels are found throughout Glen Canyon. "Pecked and incised figures depict mountain sheep, human figures, human handprints and animal tracks. Geometric figures range from circles and spirals to complex rectilinear patterns; the human figures have triangular bodies. Painted figures have been reported for both sides of the river.... Petroglyph panels of such quality are lacking from the highland regions adjacent to Glen Canyon". Studies indicate a chronology for the Lower Glen Canyon prehistory, "from pre-A. D. 1 to the 15th century and recorded history from 1776 to the present". A Late Basketmaker II Era is represented by several sites.
Radiocarbon dates from charcoal material are from A. D. 250 to 440. Basketmaker III is not found in the Lower Glen Canyon, but is documented in Navajo Canyon, a large left bank tributary of the Colorado River, within the geographical area of the Lower Glen Canyon. Basketmaker III introduces fired pottery Lino Black-on-gray and Lino Gray, some small amounts of Lino Fugitive Red and Obelisk Gray; the Basketmaker culture is believed to have lasted than Pueblo I. Pueblo I Era remains are found at Rock Creek in Lower Glen Canyon, in Navajo Canyon; the pottery types are Kana-a Black-on-white, Deadmans Black-on-red, Kana-a Gray, made from deposits found in Lizard Alcove. Pueblo I is the best documented period of Navajo Canyon, beginning in 800 A. D, lasting 200 years. "Pueblo II in Navajo Canyon is represented by the absence of Kana-a Black-on-white and the dominance of Black Mesa Black-on-white". Pueblo II and early Pueblo III is the best documented cultural area in Lower Glen Canyon corresponding with habitation on Cummings Mesa.
Pottery includes Tusayan varieties, Black-on-white, Black-on-red, Red Wear Polychromes. Hopi people from the Jeddito area came into the canyons in the 14th century, represented by Yellow Wares Jeddito Black-on-yellow, Jeddito plain. Most of the ceramic material found in the main canyon was made in the highlands, although it is possible some pottery was manufactured in Lower Glen Canyon. Clay deposits are found along the river, some crude pottery specimens, that may have been made there. Only four burials were found in Lower Glen Canyon at three sites. Trash dumps are not common at most sites; this is more evidence to suggest the seasonal occupation of farmers. Cultural similarities are based on the absence, of certain types of ceramic wares. Group types of pottery including Kayenta, with Fremont, Mesa Verde or Anasazi types of White and Desert Gray Ware were found on the right bank of the Colorado. Basketmaker II is characterized by a lack of pottery, as well as above ground and underground cists lined with slabs.
There is little evidence of permanent occupation except at Talus Ruin, a small pueblo with a kiva, a