Amistad Dam

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Amistad Dam
Amistad-NRA.jpg
Amistad Dam
Country United States / Mexico
Location Val Verde County, Texas / Acuña Municipality, Coahuila
Coordinates 29°27′01″N101°03′28″W / 29.45028°N 101.05778°W / 29.45028; -101.05778 Coordinates: 29°27′01″N101°03′28″W / 29.45028°N 101.05778°W / 29.45028; -101.05778
StatusIn use
Construction began1963
Opening date1969 (1969)
Construction costUS$125 million ($808 million in 2014)
Owner(s) International Boundary and Water Commission
Dam and spillways
Type of dam Earthfill
Impounds Rio Grande
Height254 ft (77 m)
Length32,022 ft (9,760 m)
Dam volume17,055,000 cu yd (13,039,000 m3)
Spillway type Ogee crest, 16 tainter gates
Spillway capacity1,507,000 cu ft/s (42,700 m3/s)
Reservoir
Creates Amistad Reservoir
Total capacity5,658,600 acre⋅ft (6.9798 km3)
Surface area64,900 acres (26,300 ha)
Power Station
Hydraulic head 234 ft (71 m)
Turbines 4x Francis
Installed capacity 132 MW

Amistad Dam (Spanish: Presa la Amistad) is a major embankment dam across the Rio Grande between Texas, United States, and Coahuila, Mexico. Built to provide irrigation water storage, flood control, and hydropower generation, it is the largest dam along the international boundary reach of the Rio Grande. [1] The dam is over 6 miles (9.7 km) long, lies mostly on the Mexican side of the border, and forms Amistad Reservoir. [2] It supplies water for irrigation in the Rio Grande Valley, 574 miles (924 km) upstream of the Rio Grande's mouth on the Gulf of Mexico at Brownsville, Texas/Matamoros, Tamaulipas. [3]

Contents

The dam is owned and operated by the International Boundary and Water Commission (IBWC), and also facilitates the Amistad Dam Port of Entry. Amistad is derived from the Spanish word for "friendship", representing the two nations' cooperation on the dam. [4]

History

Because of the Rio Grande's frequent floods and droughts, the sharing of its water between the US and Mexico has been a contentious issue since the 1800s. The 1906 Treaty for Equitable Distribution of the Waters of the Rio Grande enabled the construction of Elephant Butte Dam, the first major Rio Grande dam, in New Mexico. While this benefited water users along the middle Rio Grande, it did little to help the lower Rio Grande Valley, where water flows remained uncontrolled. The 1944 Treaty relating to the utilization of waters of the Colorado and Tijuana Rivers and of the Rio Grande authorized the IBWC to build dams on the uncontrolled border segment of the Rio Grande. The first dam to be completed under the treaty was Falcon Dam in 1953. [5]

After the Rio Grande flooded massively in 1954, with a peak flow of 1,158,000 cubic feet per second (32,800 m3/s) recorded at Del Rio, [6] planners realized that a much larger dam would be needed to control the river and two unregulated tributaries, the Pecos and Devils Rivers. The proposed site for the larger dam was about a mile (1.6 km) below the confluence of the Devils River and 12 miles (19 km) upstream of Del Rio. [5] During the initial planning stage, it was known as "Diablo Reservoir", a nod to the name of Devils River (diablo meaning "devil" in Spanish). The final design was approved by the two governments as Minute 207, and authorized by an act of U.S. Congress on July 7, 1960. [7] Work at the dam site began in August 1963 with foundation drilling and grouting in the river bed to support the future concrete section of the dam. [8] Actual construction of the dam itself began in January 1965 and water was first impounded in 1968. [8] U.S. president Richard Nixon and Mexican president Gustavo Díaz Ordaz dedicated the dam in 1969. [1]

The construction of the dam required the relocation of 14.3 miles (23.0 km) of the Southern Pacific Railroad tracks, 19 miles (31 km) of highways, and two bridges. [3] When the reservoir filled, it inundated ancient rock art left by Native Americans who once lived in the areas. [9] More than 170 archaeological sites were cataloged during salvage operations between 1958 and 1969, a difficult undertaking due to the arid and remote conditions of the area. [10]

The hydroelectric power plants were added later, with the US plant completed in 1983 and the Mexican plant in 1987. [11] Of the dam's roughly US$125 million cost, the US paid about 57% and Mexico 43%, in accordance with the division of water storage rights in the reservoir. [7]

In 1993, the dam was determined to be silting up at the rate of 14,000 acre-feet (17,000,000 m3) per year, about 31% greater than had been expected at the time of construction. [12]

Specifications

Dam and spillways

The dam has a total length of 32,022 feet (9,760 m), almost 6 miles (10 km), of which 22,347 feet (6,811 m) are in Mexico and 9,585 feet (2,922 m) in the United States. The center section at the Rio Grande is a concrete gravity dam 2,182 feet (665 m) long, with the remainder being earthen embankment. In total, the dam contains 13.5 million cubic yards (10,300,000 m3) of earth, 1.8 million cubic yards (1,400,000 m3) of concrete, 1.76 million cubic yards (1,300,000 m3) of riprap, and 12,500 tons (11,300 metric tons) of steel. The maximum height above the riverbed is 254 feet (77 m), and the elevation at the dam crest is 1,152.3 feet (351.2 m) above sea level. [3] The roadway along the dam crest is 32.8 feet (10.0 m) wide. [8]

The embankments are protected on both sides by riprap to reduce erosion. The riprap is 9.8 feet (3.0 m) thick on the upstream (reservoir) side and 3.28 feet (1.00 m) thick on the downstream side. [8] Because the dam is founded on karstic limestone of the Georgetown formation, a very deep grout curtain was extended underground to block seepage and the risk of dam failure by internal erosion. Despite this, more than 30 sinkholes have been discovered near the upstream side of the dam and seepage rates have been recorded at over 180 cubic feet per second (5.1 m3/s), which may be much higher due to unmeasured seepage on the Mexican side of the dam. However, because the water is traveling through bedrock and not the dam itself, this poses little threat to the dam's structural stability. [13] During extreme flood events, however, this may still be a cause for concern. [14]

Flood waters are released through a concrete ogee crest spillway with 16 tainter gates. The gates measure 50 by 54 feet (15 m × 16 m) and can spill up to 1,507,000 cubic feet per second (42,700 m3/s). [3] The spillway empties into a stilling basin 950 feet (290 m) long, designed to dissipate erosion. [8]

Water supply and flood control

The Amistad reservoir covers 65,000 acres (26,000 ha) at normal (conservation) water levels of 1,117 feet (340 m) above sea level. It is one of the largest lakes in the Rio Grande system by both surface area and volume. Of the reservoir's 5,535,000-acre-foot (6.827 km3) capacity, 61% is dedicated to water conservation and sediment control, 32% to flood control, and 7% to surcharge (flood storage above the top of the spillway gates, but below the crest of the dam). At the top of the flood control pool, the reservoir is 84,000 acres (34,000 ha) and at the top of the surcharge pool it is 89,000 acres (36,000 ha). The lowest lake elevation at which water can be released is 930 feet (280 m), or 187 feet (57 m) below normal levels. [3] At the top of the conservation pool, the reservoir extends 78 miles (126 km) up the Rio Grande, 25 miles (40 km) up the Devils River, and 14 miles (23 km) up the Pecos River. It has a shoreline of 851 miles (1,370 km), of which 547 miles (880 km) are in the US and 304 miles (489 km) are in Mexico. [15] [16]

Southern Pacific Railroad and U.S. Route 90 bridges on Amistad Reservoir Amistad Res & Bridges2.jpg
Southern Pacific Railroad and U.S. Route 90 bridges on Amistad Reservoir

About 56.2% of the water released from Amistad Dam is allocated to the United States, and 43.8% to Mexico. The IBWC determines the fraction of water stored in Amistad Reservoir belonging to either country on a biweekly basis, based on this allocation. [17] The reservoir levels fluctuate greatly due to the region's highly variable annual precipitation as well as heavy water use. The record high level was 1,135.66 feet (346.15 m) on September 22, 1974. [18] It reached a record low level of 1,055.93 feet (321.85 m) on May 23, 2013, or 61 feet (19 m) below normal levels, after several consecutive years of drought. [19]

The average annual inflow to Amistad Reservoir is about 2,080,000 acre-feet (2.57 km3). [20] Although the majority – about 70% – of the inflows to Amistad Reservoir comes from the Rio Grande, Devils, and Pecos Rivers, about 30% is from local springs. Inflows typically peak between August and October due to monsoon storms and hurricanes that strike the Gulf Coast. Flood flows caused by hurricanes are short-lived, but can be extreme, [21] with a maximum (since dam construction) of more than 800,000 cubic feet per second (23,000 m3/s) in late September, 1974. [6] Dam operators held the outflow from Amistad Dam at about 62,200 cubic feet per second (1,760 m3/s), [6] sparing a large part of the Rio Grande Valley from flooding. [21]

Because of diversions of the Rio Grande in the upriver U.S. states of Colorado and New Mexico, the Rio Conchos (which originates in Chihuahua, Mexico) actually provides the majority of the water flowing from the Rio Grande into the lake. Increasing water use in upriver communities has caused a steady decline in Rio Grande flows throughout the 20th and 21st centuries and has led to concerns about future water levels and supplies at Amistad. [12] [22]

Power generation

The dam has two hydroelectric power stations, one on either side of the border, with a capacity of 66 megawatts (MW) each. The maximum hydraulic head is 234 feet (71 m), with a minimum of 115 feet (35 m) required to run the plants. The four generators have a capacity of 33 MW each and are powered by a 42,300-hp (31.54-MW) Francis turbine. The maximum combined water flow through the power plants is 9,200 cubic feet per second (260 m3/s). [3]

In 2009, the Amistad Dam plants produced a total of 296,734,000 kilowatt hours. [23] [24]

Border crossing

The Amistad Dam Port of Entry was built when Amistad Dam was completed in 1969. The Dam was a bi-national effort to establish flood control on the Rio Grande and provide sources of water. Although US Department of Transportation statistics combine traffic counts with Del Rio Texas Port of Entry, approximately 65,000 vehicles crossed the dam into the US in 2005. [25] The border station was rebuilt by the US Army Corps of Engineers in 2012. [26]

Recreation

The dam and reservoir are part of the Amistad National Recreation Area.

See also

Related Research Articles

Rio Grande Major river forming part of the US–Mexico border

The Rio Grande, known in Mexico as the Río Bravo del Norte or simply the Río Bravo, is one of the principal rivers in the southwestern United States and in northern Mexico. The length of the Rio Grande is 1,896 miles (3,051 km). It originates in south-central Colorado, in the United States, and flows to the Gulf of Mexico. The Rio Grande drainage basin (watershed) has an area of 182,200 square miles (472,000 km2); however, the endorheic basins that are adjacent to and within the greater drainage basin of the Rio Grande increase the total drainage-basin area to 336,000 square miles (870,000 km2).

Pecos River River in New Mexico and Texas, United States

The Pecos River originates in north-central New Mexico and flows into Texas, emptying into the Rio Grande. Its headwaters are on the eastern slope of the Sangre de Cristo mountain range in Mora County north of Pecos, NM, at an elevation of over 12,000 feet (3,700 m). The river flows for 926 miles (1,490 km) before reaching the Rio Grande near Del Rio. Its drainage basin encompasses about 44,300 square miles (115,000 km2).

Elephant Butte Reservoir Reservoir on the Rio Grande in New Mexico, United States

Elephant Butte Reservoir is a reservoir on the southern part of the Rio Grande in the U.S. state of New Mexico, 5 miles (8.0 km) north of Truth or Consequences. The reservoir is the 84th largest man-made lake in the United States and the largest in New Mexico by total surface area and peak volume. It is the only place in New Mexico that one can find pelicans perched on or alongside the lake. There are also temporary US Coast Guard bases stationed at Elephant Butte. It is impounded by Elephant Butte Dam and is part of the largest state park in New Mexico, Elephant Butte Lake State Park.

Elephant Butte Dam Dam on the Rio Grande in New Mexico, United States

Elephant Butte Dam or Elephant Butte Dike, originally Engle Dam, is a concrete gravity dam on the Rio Grande near Truth or Consequences, New Mexico. The dam impounds Elephant Butte Reservoir, which is used mainly for agriculture but also provides for recreation, hydroelectricity, and flood and sediment control. The construction of the dam has reduced the flow of the Rio Grande to a small stream for most of the year, with water being released only during the summer irrigation season or during times of exceptionally heavy snow melt.

The International Boundary and Water Commission is an international body created by the United States and Mexico in 1889 to apply the rules for determining the location of their international boundary when meandering rivers transferred tracts of land from one bank to the other, as established under the Convention of November 12, 1884.

Amistad National Recreation Area

Amistad National Recreation Area is a national recreation area managed by National Park Service (NPS) that includes the area around the Amistad Reservoir at the confluence of the Rio Grande, the Devils River, and the Pecos River near Del Rio in Val Verde County, Texas. The reservoir was created by the Amistad Dam, completed in 1969, located on the Rio Grande at the United States-Mexico border across from the city of Ciudad Acuña in the Mexican state of Coahuila. Amistad, Spanish for "friendship," refers broadly to the close relationship and shared history between Ciudad Acuña and Del Rio.

Amistad Reservoir Body of water

Amistad Reservoir is a reservoir on the Rio Grande at its confluence with the Devils River 12 miles (19 km) northwest of Del Rio, Texas. The lake is bounded by Val Verde County on the United States side of the international border and by the state of Coahuila on the Mexican side of the border; the American shoreline forms the Amistad National Recreation Area. The reservoir was formed in 1969 by the construction of Amistad Dam. The dam and lake are managed jointly by the governments of the United States and Mexico through the International Boundary and Water Commission. The name of the dam and lake is the Spanish word for "friendship". The reservoir is also known as Lake Amistad.

Devils River (Texas)

The Devils River in southwestern Texas, part of the Rio Grande drainage basin, has limited areas of whitewater along its length. It begins in northwest Sutton County, at 30°19′40″N100°56′31″W, where six watercourses come together, Dry Devils River, Granger Draw, House Draw, Jackson, Flat Rock Draw, and Rough Canyon. It flows southwest for 94 miles (151 km) through Val Verde County and empties into the northeastern shore of the Amistad Reservoir, an impoundment of the Rio Grande near Del Rio, Texas on the Texas/Mexico border, 29°27′33″N101°3′34″W. The discharge of the Devils River, as measured at IBWC gaging station 08-4494.00 near the river's mouth, averages 362 cubic feet per second (10.3 m3/s), with a maximum of 122,895 cubic feet per second (3,480 m3/s) and a minimum of 54 cubic feet per second (1.53 m3/s). Its drainage basin above that point is 10,259 square kilometres (3,961 sq mi).

Rio Grande Project

The Rio Grande Project is a United States Bureau of Reclamation irrigation, hydroelectricity, flood control, and interbasin water transfer project serving the upper Rio Grande basin in the southwestern United States. The project irrigates 193,000 acres (780 km2) along the river in the states of New Mexico and Texas. Approximately 60 percent of this land is in New Mexico. Some water is also allotted to Mexico to irrigate some 25,000 acres (100 km2) on the south side of the river. The project was authorized in 1905, but its final features were not implemented until the early 1950s.

The Rio Hondo is a 79-mile-long (127 km) river in southern New Mexico which begins at the confluence of the Rio Bonito and Rio Ruidoso rivers near the town of Hondo, New Mexico. The river flows eastward through the Hondo Valley in the foothills of the Sierra Blanca and Capitan Mountains, roughly paralleling the route of U.S. Route 70 through the towns of Picacho and Tinnie. Near the community of Riverside the river passes through a deep canyon before entering the rolling hills west of Roswell.

Caballo Dam Dam on the Rio Grande in New Mexico, United States

Caballo Dam is an earthen dam on the Rio Grande about 15 miles (24 km) downstream from Truth or Consequences, New Mexico, United States. In conjunction with Elephant Butte Dam, which lies about 25 miles (40 km) upstream, it regulates the discharge of the river in the lower Rio Grande Valley of New Mexico. Caballo serves as an afterbay for the Elephant Butte Reservoir, i.e. it stores water released from Elephant Butte for hydroelectricity generation purposes and discharges it in the dry season to provide for irrigation agriculture downstream. The dam is an important part of the Rio Grande Project. A secondary purpose of the dam was to compensate for lost capacity in Elephant Butte Lake due to sedimentation.

El Vado Dam Dam in Rio Arriba County, New Mexico

El Vado Dam impounds the Rio Chama in the U.S. state of New Mexico, about 105 miles (169 km) north-northwest of New Mexico's largest city, Albuquerque and about 80 miles (130 km) northwest of the capital city of Santa Fe. The earth-filled structure forms El Vado Lake, a storage reservoir for the Middle Rio Grande Project, and has been designated as a New Mexico Historic Civil Engineering Landmark by the American Society of Civil Engineers.

Abiquiu Dam Dam in Rio Arriba County, New Mexico

Abiquiu Dam is a dam on the Rio Chama, located about 60 miles (97 km) northwest of Santa Fe in Rio Arriba County, New Mexico. Built and operated by the U.S. Army Corps of Engineers (USACE), the dam is an earth embankment structure 354 feet (108 m) high and 1,800 feet (550 m) long, containing 11.8 million cubic yards of fill. The dam forms Abiquiu Lake, one of the largest lakes in New Mexico with a full storage capacity of 1,369,000 acre-feet (1,689,000 dam3) and 5,200 acres (2,100 ha) of water. To date, the reservoir has never filled to capacity, with a record high of 402,258 acre-feet (496,178 dam3), 29.4% of full pool, on June 22, 1987. The dam's primary purpose is flood control, in addition to irrigation and municipal water storage, and hydroelectric generation.

San Acacia is a small unincorporated community and census-designated place in Socorro County, New Mexico, United States. It was once a prosperous railway town, but is now largely deserted. There is a nearby diversion dam on the Rio Grande, important in irrigation.

Middle Rio Grande Project

The Middle Rio Grande Project manages water in the Albuquerque Basin of New Mexico, United States. It includes major upgrades and extensions to the irrigation facilities built by the Middle Rio Grande Conservancy District and modifications to the channel of the Rio Grande to control sedimentation and flooding. The bulk of the work was done by the United States Bureau of Reclamation and the United States Army Corps of Engineers in the 1950s, but construction continued into the 1970s and maintenance is ongoing. The project is complementary to the San Juan-Chama Project, which transfers water from the San Juan River in the Colorado River Basin to the Rio Grande. Although distribution of water from the two projects is handled through separate allotments and contracts, there is some sharing of facilities including the river itself. The ecological impact on the river and the riparian zone was the subject of extended litigation after a group of environmentalists filed Rio Grande Silvery Minnow v. Bureau of Reclamation in 1999.

Heron Dam Dam in Rio Arriba County, New Mexico

Heron Dam is a storage dam Rio Arriba County, in northern New Mexico in the southwestern United States, just north of the El Vado Dam. It is owned and operated by the United States Bureau of Reclamation. The dam is about 9 miles west of the town of Tierra Amarilla.

Avalon Dam Dam in Eddy County, New Mexico

Avalon Dam is a small dam on the Pecos River about 5 miles (8.0 km) north of Carlsbad, New Mexico, United States. The dam is a storage and regulating reservoir, and diverts water into the main canal of the Carlsbad Project, an irrigation scheme.

The American Dam, or American Diversion Dam, is a diversion dam on the Rio Grande in El Paso, Texas, that divides the river water between Mexico and the U.S. It is about 140 feet (43 m) north of the point where the west bank of the river enters Mexico, 3.5 miles (5.6 km) from the business center. The dam is operated by the International Boundary and Water Commission. It started operation in 1938.

The International Diversion Dam is a diversion dam on the Rio Grande in Ciudad Juárez. The dam is operated by the International Boundary and Water Commission, and diverts water into the Acequia Madre for use in irrigation in Mexico. Water is diverted under the terms of the 1906 treaty on usage of Rio Grande water between the United States and Mexico.

The Riverside Diversion Dam was a diversion dam on the Rio Grande to the southeast of El Paso, Texas. The dam was owned by the United States Bureau of Reclamation, and diverted water into the Riverside Canal for use in irrigation in the El Paso Valley. The dam became obsolete with completion of a cement-lined canal carrying water from the upstream American Diversion Dam to the head of the canal. It was partially removed in 2003.

References

  1. 1 2 "Archived copy". Archived from the original on 2016-04-03. Retrieved 2016-04-05.{{cite web}}: CS1 maint: archived copy as title (link)
  2. ↑ "Amistad Dam and Powerplants". CRSP Management Center. Western Area Power Administration. Archived from the original on 2011-07-21. Retrieved 2011-01-25.
  3. 1 2 3 4 5 6 "Archived copy" (PDF). Archived from the original (PDF) on 2014-07-14. Retrieved 2014-06-08.{{cite web}}: CS1 maint: archived copy as title (link)
  4. ↑ San Antonio. ISBN   9780762752119.
  5. 1 2 https://cdn.loc.gov/master/pnp/habshaer/tx/tx1100/tx1177/data/tx1177data.pdf [ bare URL PDF ]
  6. 1 2 3 "Archived copy" (PDF). Archived from the original (PDF) on 2013-02-17. Retrieved 2016-04-05.{{cite web}}: CS1 maint: archived copy as title (link)
  7. 1 2 "Departments of State, Justice, Commerce, the Judiciary and Related Agencies ... - United States. Congress. House. Appropriations - Google Books". 1967.
  8. 1 2 3 4 5 "Archived copy" (PDF). Archived from the original (PDF) on 2016-03-08. Retrieved 2016-04-05.{{cite web}}: CS1 maint: archived copy as title (link)
  9. ↑ "Amistad Reservoir". TSHA Texas State Historical Association.
  10. ↑ "Lower Pecos-Before Amistad".
  11. ↑ "Amistad International Reservoir (Rio Grande River Basin)".
  12. 1 2 "Archived copy" (PDF). Archived from the original (PDF) on 2016-10-11. Retrieved 2016-04-05.{{cite web}}: CS1 maint: archived copy as title (link)
  13. ↑ "Archived copy" (PDF). Archived from the original (PDF) on 2016-04-19. Retrieved 2016-04-05.{{cite web}}: CS1 maint: archived copy as title (link)
  14. ↑ "Concerns raised over safety of Falcon, Amistad dams". Valley Morning Star.[ permanent dead link ]
  15. ↑ USGS Topo Maps for United States (Map). Cartography by United States Geological Survey. ACME Mapper. Retrieved 2016-01-04.
  16. ↑ "Frequently Asked Questions".
  17. ↑ "Water Data For Texas".
  18. ↑ "Archived copy" (PDF). Archived from the original (PDF) on 2016-10-11. Retrieved 2016-04-05.{{cite web}}: CS1 maint: archived copy as title (link)
  19. ↑ "Lake Levels".
  20. ↑ http://riogrande.tamu.edu/media/3901/miyamoto-8-amistad-pub.pdf [ bare URL PDF ]
  21. 1 2 "Departments of State, Justice, and Commerce, the Judiciary, and related ..." 1977.
  22. ↑ http://opensiuc.lib.siu.edu/cgi/viewcontent.cgi?article=1003&context=jcwre [ bare URL PDF ]
  23. ↑ Forum One Communications. "CARMA - Carbon Monitoring for Action".
  24. ↑ Forum One Communications. "CARMA - Carbon Monitoring for Action".
  25. ↑ "Border Crossing Travel Time Study, FINAL Study Report, Volume II: TxDOT Laredo District". RJ RIVERA Associates, Inc. for Texas Department of Transportation, Transportation Planning and Programming Division. Archived from the original on 26 December 2008. Retrieved 22 July 2012.
  26. ↑ Frisinger, James. "New Amistad Dam port of entry opens at Del Rio, Texas, border crossing". US Army. Retrieved 28 September 2018.
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