The Yeywa Hydropower Station ( my, ရဲရွာရေအားလျှပ်စစ်ဓာတ်အားပေးစက်ရုံ), located on the

Myitnge River Myitnge River ( my, မြစ်ငယ် or Nam Tu, also known as Dokhtawaddy River (), is a major tributary of Ayeyarwady River (Irrawaddy) in Myanmar (Burma). The name Myitnge in Burmese and Dokhtawaddy in Pali both mean "little river", by cont ...

, southeast of Mandalay city, at Yeywa village in

Kyaukse Township Kyaukse Township is a township of Kyaukse District in the Mandalay Region of Burma. It makes up the area including the town of Kyaukse Kyaukse ( my, ကျောက်ဆည် မြို့, ) is town and capital of Kyaukse District in Mandal ...

Mandalay Region Mandalay Region ( my, မန္တလေးတိုင်းဒေသကြီး, ; formerly Mandalay Division) is an administrative division of Myanmar. It is located in the center of the country, bordering Sagaing Region and Magway Region t ...

in central

Myanmar Myanmar, ; UK pronunciations: US pronunciations incl. . Note: Wikipedia's IPA conventions require indicating /r/ even in British English although only some British English speakers pronounce r at the end of syllables. As John Wells explai ...

, is the country's first roller-compacted concrete (RCC)

dam A dam is a barrier that stops or restricts the flow of surface water or underground streams. Reservoirs created by dams not only suppress floods but also provide water for activities such as irrigation, human consumption, industrial use ...

, and the site of a

hydroelectric power plant Hydroelectricity, or hydroelectric power, is electricity generated from hydropower (water power). Hydropower supplies one sixth of the world's electricity, almost 4500 TWh in 2020, which is more than all other renewable sources combined an ...

, the largest in the country.

Background

The plant feasibility study was done in 1999. In May 2001, agreement of consulting service between MEPE and COLENCO Power Engineering, Ltd. had signed. In 2003 agreement part 2 for Detail Design, preparation of tender documents and guidance services for construction supervision was signed. The river diversion was completed on December 12, 2004 and RCC placement began on February 8, 2006. The Burmese government announced plans for the Yeywa Dam in late 2001. In 2004, Burma's Ministry of Electric Power (MEPE) signed a Memorandum of understanding with a consortium of Chinese companies created by China International Trust & Investment Co. (CITIC) and Sinohydro Corporation for implementation of the project. On September 2, 2005, a ceremony to mark the signing of contract between the Hydroelectric Power Department under the Ministry of Electric Power and the China National Heavy Machinery Corporation (CHMC) for the Yeywa Hydroelectric Power Project was held in

Yangon Yangon ( my, ရန်ကုန်; ; ), formerly spelled as Rangoon, is the capital of the Yangon Region and the largest city of Myanmar (also known as Burma). Yangon served as the capital of Myanmar until 2006, when the military government ...

angoon Angoon (sometimes formerly spelled Angun, tli, Aangóon) is a city on Admiralty Island in Hoonah-Angoon Census Area, Alaska, United States. At the 2000 census the population was 572; by the 2010 census the population had declined to 459. The ...

Site work began in 2004 and all four generators were commissioned in 2010. The project was completed in November 2011.

Design

The dam design comprises a high RCC embankment gravity dam, built of of concrete. The dam includes an ungated

spillway A spillway is a structure used to provide the controlled release of water downstream from a dam or levee, typically into the riverbed of the dammed river itself. In the United Kingdom, they may be known as overflow channels. Spillways ensure th ...

of reinforced conventional concrete cast after RCC placement, located in the central section of the dam for a design flood water discharge of . The wide spillway consists of eight wide and high outlets. There is a 790 MW (4 × 197.5 MW) powerhouse at the toe of the dam on the south bank of the river. The power house containing the turbines and generators is long, wide and high. The power house and dam structures are designed to withstand earthquakes of up to eight on the

Richter scale The Richter scale —also called the Richter magnitude scale, Richter's magnitude scale, and the Gutenberg–Richter scale—is a measure of the strength of earthquakes, developed by Charles Francis Richter and presented in his landmark 1935 ...

. The power generation facilities consist of four water intakes, each consisting of diameter and long high tensile steel pipe

penstock A penstock is a sluice or gate or intake structure that controls water flow, or an enclosed pipe that delivers water to hydro turbines and sewerage systems. The term is inherited from the earlier technology of mill ponds and watermills. H ...

s and four vertical axis Francis turbines and generator units and associated electro-mechanical and auxiliary equipment installed in an open air powerhouse. Four water intake towers were built as conventional reinforced concrete structures abutting the upstream (east) face of the RCC dam. This enabled the contractor to build the towers above the penstock inlets before the start of RCC construction in order to minimise interference with the RCC construction activity. Four Penstock of Yeywa Dam

There is one permanent diameter, long, diversion tunnel in the north river bank serving as a bottom outlet. This outlet tunnel enables reservoir drawdown and control during reservoir filling, maintenance of downstream riparian river flow during the impounding period and, together with the spillway, serves to redirect flood waters of the Myitnge river and maintain river flow during an emergency when all turbines are closed down. Two double circuit 230 kV

transmission lines In electrical engineering, a transmission line is a specialized cable or other structure designed to conduct electromagnetic waves in a contained manner. The term applies when the conductors are long enough that the wave nature of the transmis ...

connect the main transformers located on the downstream side of the powerhouse to an open-air switchyard, located on the south river bank downstream of the powerhouse. The Yeywa Dam will supply electric power to the Meiktila Sub-Power Station through the long Yeywa-Meiktila 230 kV double power line link to the southwest and to the Bellin Substation through another long 230 kV double power line link in the west. The Bellin and the Meiktila Sub-Power Stations will be linked to each other with 100 km long 23 kV double power lines. US$45.8 million worth of 230 KVA cables and equipment were used for construction and linking of these sub- power stations. Yeywa Dam 2

Construction

Several construction companies from China, Switzerland, and

Britain Britain most often refers to: * The United Kingdom, a sovereign state in Europe comprising the island of Great Britain, the north-eastern part of the island of Ireland and many smaller islands * Great Britain, the largest island in the United King ...

and Myanmar have been involved in various stages of the Yeywa Dam, including the Chinese companies:

Export-Import Bank of China The Export–Import Bank of China (Chexim - China Exim Bank) () is one of two institutional banks in China chartered to implement the state policies in industry, foreign trade, economy, and foreign aid to other developing countries, and pro ...

(China Exim Bank), China Gezhouba Group Co. (CGGC), China National Electric Equipment Co., Hunan Savoo Overseas Water & Electric Engineering Co. and China National Heavy Machinery Co. The Swiss company Colenco Power Engineering, the Germany-based company Voith Siemens, and the British Malcolm Dunstan & Associates. A key aspect in the successful construction of the Yeywa RCC dam was comprehensive training of the local staff during preparative for and initial stages of the construction. High-Tech Concrete Technologies (HTCT), a member of Shwe Taung Group, was the one who has been succeeding the knowledge from local perspective. Up to 5,000 workers were employed on this large construction project. Equipment selected for the concreting operations include Putzmeister's MX 32 stationary boom, an M 38 truck-mounted concrete pump and two BSA 2,109 HP stationary pumps. A bridge was built across the river, just downstream of the dam, to replace the ferry system, which had been the only means for transport across the river. Various studies were conducted during construction, and identified risk factors, one of them was "Key Organizational Risk Factors: A Case Study of Hydroelectric Power Projects in Myanmar".

Impact

of electricity per year will be supplied to the Mandalay Division regional power grid for public and private consumption. In 2005 the ''Myanmar Times'' reported that three villages near the dam had been relocated. The villagers had depended on the Myitnge River for their fishing, farming and logging livelihoods, the sources of which will be flooded by the dam. Ancient cultural sites like the Sappa Sukha Htattaw Temple will also be flooded and forever lost.

References

External sources