El Cajón Dam (Honduras)
Encyclopedia
The El Cajón Dam, officially known as Central Hidroeléctrica Francisco Morazán, is a hydroelectric power plant located in Western Honduras
. The dam impounds the Comayagua river which derives its large volume from two large tributaries, Humuya
and Sulaco
. El Cajón is a double arch dam
, which uses parabolic geometry in horizontal and vertical axises to spread the weight of the impounded water to canyon walls which act as buttresses. Overall, the dam is the fifth highest dam in the Americas, 16th highest in the world. El Cajón is also the highest arch dam in the western hemisphere, and the sixth highest arch dam worldwide.
, the country's capital, and 80 km (50 mi) from San Pedro Sula
, the main Honduran industrial city.
, Illinois
, USA, began site investigation in the 1960s with initial construction beginning June 15, 1980. A multinational team of designers, builders and engineers included members from Italy
, Germany
, Switzerland
, and Panama
. Panamanian and Italian companies were responsible for the construction of the machine room, while Italian and German companies were responsible for dam construction and ancillary works. Upon completion the dam became the largest piece of infrastructure
in Honduras, requiring over half a million cubic meters of concrete to construct.
.
The important role these devices play came into focus after an 7.1 magnitude earthquake, originating 200 miles north of Tegucigalpa caused massive damage to many pieces of infrastructure May 28, 2009. These devices were critical to determining the internal deformation of the structure.
Honduras
Honduras is a republic in Central America. It was previously known as Spanish Honduras to differentiate it from British Honduras, which became the modern-day state of Belize...
. The dam impounds the Comayagua river which derives its large volume from two large tributaries, Humuya
Humuya River
-References:*Rand McNally, The New International Atlas, 1993.*CIA map: :Image:Honduras rel 1985.jpg*UN map: :Image:Un-honduras.png*...
and Sulaco
Sulaco River
-References:*Rand McNally, The New International Atlas, 1993.*CIA map: :Image:Honduras rel 1985.jpg*UN map: :Image:Un-honduras.png*...
. El Cajón is a double arch dam
Arch dam
An arch dam is a type of dam that is curved and commonly built with concrete. The arch dam is a structure that is designed to curve upstream so that the force of the water against it, known as hydrostatic pressure, presses against the arch, compressing and strengthening the structure as it pushes...
, which uses parabolic geometry in horizontal and vertical axises to spread the weight of the impounded water to canyon walls which act as buttresses. Overall, the dam is the fifth highest dam in the Americas, 16th highest in the world. El Cajón is also the highest arch dam in the western hemisphere, and the sixth highest arch dam worldwide.
Location
El Cajón is located 180 km (112 mi) from TegucigalpaTegucigalpa
Tegucigalpa , and commonly referred as Tegus , is the capital of Honduras and seat of government of the Republic, along with its twin sister Comayagüela. Founded on September 29, 1578 by the Spanish, it became the country's capital on October 30, 1880 under President Marco Aurelio Soto...
, the country's capital, and 80 km (50 mi) from San Pedro Sula
San Pedro Sula
San Pedro Sula is a city in Honduras. It is located in the northwest corner of the country, in the Valle de Sula , about 60 km south of Puerto Cortés on the Caribbean. With an estimated population of 638,259 people in the main municipality, and 802,598 in its metro area , it is the second...
, the main Honduran industrial city.
Construction
Harza Engineering of ChicagoChicago
Chicago is the largest city in the US state of Illinois. With nearly 2.7 million residents, it is the most populous city in the Midwestern United States and the third most populous in the US, after New York City and Los Angeles...
, Illinois
Illinois
Illinois is the fifth-most populous state of the United States of America, and is often noted for being a microcosm of the entire country. With Chicago in the northeast, small industrial cities and great agricultural productivity in central and northern Illinois, and natural resources like coal,...
, USA, began site investigation in the 1960s with initial construction beginning June 15, 1980. A multinational team of designers, builders and engineers included members from Italy
Italy
Italy , officially the Italian Republic languages]] under the European Charter for Regional or Minority Languages. In each of these, Italy's official name is as follows:;;;;;;;;), is a unitary parliamentary republic in South-Central Europe. To the north it borders France, Switzerland, Austria and...
, Germany
Germany
Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...
, Switzerland
Switzerland
Switzerland name of one of the Swiss cantons. ; ; ; or ), in its full name the Swiss Confederation , is a federal republic consisting of 26 cantons, with Bern as the seat of the federal authorities. The country is situated in Western Europe,Or Central Europe depending on the definition....
, and Panama
Panama
Panama , officially the Republic of Panama , is the southernmost country of Central America. Situated on the isthmus connecting North and South America, it is bordered by Costa Rica to the northwest, Colombia to the southeast, the Caribbean Sea to the north and the Pacific Ocean to the south. The...
. Panamanian and Italian companies were responsible for the construction of the machine room, while Italian and German companies were responsible for dam construction and ancillary works. Upon completion the dam became the largest piece of infrastructure
Infrastructure
Infrastructure is basic physical and organizational structures needed for the operation of a society or enterprise, or the services and facilities necessary for an economy to function...
in Honduras, requiring over half a million cubic meters of concrete to construct.
Design
Finite element design was used for the structural components of the dam. The dam is 282 meters long, and 48 meters thick at bottom. The top is 7 meters thick which is wide enough for the small service road that crosses the dam. Around 170 meters from the base of the dam, three 14.5m2 discharge tubes expel water that has passed through the machine room's turbines. Near the top of the dam is a spillway composed of four large square tubes each 14 meters wide that are opened when flow through the dam cannot be handled by the lower discharge tubes.Reservoir
The reservoir created by El Cajón spans 94 km² with a maximum capacity of around 5,700 million m³. The reservoir displaced approximately 4,700 people. While the main purpose of the reservoir is for powering El Cajón's turbines, flood control is another major benefit. Before completion of the dam, yearly flooding in the Sula valley seriously disrupted commerce for the people of Honduras. Now during the rainy season the reservoir has the ability to retain a layer of water ten meters high, and then discharge it slowly to prevent disastrous flooding. Agriculture has also benefited. Historically, during the dry season the Comayagua's flow dropped significantly to around 20 m3, the dam now provides year round flow of approximately 100 m3, which has had a significant economic impact for the region.Power Output
Eight large vertical axis turbines are located in a subterranean housing stationed in the left side of the limestone valley. Construction was done in two stages. Initially, four turbines were installed in the room; which at the time was already fairly large: 110 m long, 30 m wide, and 49 m high. The second stage of construction extended the length another 65 meters to house the remaining four turbines. Each turbine rotates at 300 R.P.M, powering its own generator capable of producing 75 megawatts. The completion of the second stage brought the total power output to 600 megawatts. The power produced there is then transmitted to a central station at 230kVKV
-In physics and chemistry:* Voltage-gated potassium channel,a large family of potassium channels* Kilovolts , 1000 volts* The rating of RPMs per volt as used in reference to the rotational speed of brushless motors...
.
Instrumentation
Initially, electrical monitoring devices commonly used in modern dams were installed, but due to high sulphur content in the surrounding rock and water, all of the devices corroded and failed. With the exception of portable monitoring equipment, El Cajón now relies entirely on mechanical devices to check its performance.- Mechanical extensometers, used for measuring settlement and linear deformation, are oriented in horizontal and vertical directions. These devices are spaced at different intervals horizontally throughout the dam with groups every 30 meters in elevation.
- V-Notch Weirs, are used to measure seepage through the curtain of the dam. One is located in a trench at the base of the dam on the lower right side
- Force balance Accelerometers are used to measure motion of the dam, which is an indication of deformation. These devices are useful in monitoring damage from seismic events.
- Inverted Pendulums. These devices measure vertical deformation of the dam. One end of thin wire is attached to an anchor which is grouted in solid rock below the dam with the other end attached to a float station that's is attached to the dam. Movement of the float relative to the anchor alerts dam operators to possible motion.
- Direct Pendulum. This device is similar in operation to the inverted pendulum except the anchor is located at the top with the float tank located at the bottom. There are 21 direct and indirect pendulums located in El Cajón.
- BourdonBourdonBourdon, bordun, or bordone normally denotes a stopped flute/flue type of pipe in an organ characterized by a very dark, heavy tone, strong in fundamental, with a quint transient but relatively little overtone development...
Pressure Gages are used to measure the static pressure of the water contained in the reservoir. - GeodeticGeodetic systemGeodetic systems or geodetic data are used in geodesy, navigation, surveying by cartographers and satellite navigation systems to translate positions indicated on their products to their real position on earth....
SurveyingSurveyingSee Also: Public Land Survey SystemSurveying or land surveying is the technique, profession, and science of accurately determining the terrestrial or three-dimensional position of points and the distances and angles between them...
. stations are located at fixed reference points in the area surrounding the dam. "Object" points are installed on the face of the dam (look closely you can see the yellow drums). Surveyors use devices such as theodolites and total stations to compare changes in distance and elevation of the object points on the dam to the reference points. The information gathered gives dam operators a picture of how the dam is settling or if motion of the face is occurring. - Inclinometers are installed in the dam's abutments to monitor slope stability. The device measures linear deformation.
- Seismographs are used to monitor vibration of the structural elements due to geologic activity. Because El Cajón lies on three fault lines the collection of seismic information is crucial to making decisions about the dam's operation.
The important role these devices play came into focus after an 7.1 magnitude earthquake, originating 200 miles north of Tegucigalpa caused massive damage to many pieces of infrastructure May 28, 2009. These devices were critical to determining the internal deformation of the structure.