#The_Tungabhadra Dam #Pampa Sagar, #துங்கபத்ரா அணை

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நேற்று ஹம்பியைப் பார்த்துவிட்டு சென்னைக்குத் திரும்பும் வழியில் துங்கபத்ரா அணையைப் பார்க்கக் கூடிய வாய்ப்புக் கிடைத்து. 

  

இந்த அணையைக் கட்டும் பணிக்கான அறிவியல்ரீதியான திட்டமிடல் பணிகளை 1940 - இல் தமிழத்தைச் சேர்ந்த பொதுப்பணித்துறை தலைமைப் பொறியாளர் எம்.எஸ்.திருமலை அய்யங்கார் தொடங்கினார். அணைக்கான இந்த அணையின் லோ லெவலைக் கட்டும் வாய்ப்பு திருமலை அய்யங்காருக்குக் கிடைத்தது. 1945 இல் அணைக்கான அடிக்கல் நாட்டப்பட்டு அதன் பணிகள் 1952- இல் முடிந்த்து. 1953- இல் அணை முழுமையாகச் செயல்படத் தொடங்கியது.

இந்திராகாந்தி பிரதமராக இருந்த காலத்தில்  மத்திய நீர்வளத்துறை அமைச்சராக இருந்த கே.எல்.ராவ் 09.01.1967 – இல் உயர்மட்ட அணைத் திட்டத்தை நாட்டுக்கு அர்ப்பணித்தார்.

 துங்கபத்ரா நதியின் கரையின் ஒரு பகுதி ஆந்திராவைச் சாரும். மறுகரை கர்நாடகாவைச் சேர்ந்ததாகும். துங்கபத்ரா அணை கர்நாடக மாநிலத்தில் உள்ளது. நீரை இரு மாநிலங்களும் பகிர்ந்து கொள்கின்றன. மிகப் பெரிய அணைத்திட்டமான துங்கபத்ரா அணைத்திட்டம், இந்திய அறிவியல் வளர்ச்சியைக் காட்டும் முக்கியமான மைல் கல்லாகும்.

இரண்டு ஆண்டுகளுக்கு முன்பு துங்கபத்ரா நதியில் வெள்ளம் வந்து, இரு மாநிலங்களிலும் பெரிய அழிவுகளை ஏற்படுத்தியது என்பதுதான் கடந்த கால செய்தி. இந்த பயணத்தில் அன்புத் தம்பி கேசவனும், அன்பு நண்பர் சுரேஷும் அவருடைய துணைவியார்  ரேகாவும் இணைந்து இருந்தனர்.

The Tungabhadra Dam, also known as Pampa Sagar, is a water reservoir constructed across the Tungabhadra River in the city of Hosapete Bellary district, Karnataka, India. It is a multipurpose dam serving irrigation, electricity generation, flood control, etc. for the state. It is one of the only two non-cement dams in India, the other being the Mullaperiyar Dam in Kerala. The dam is built of surki mortar, a combination of mud and limestone, commonly used at the time of its construction.

The dam was a joint project undertaken in 1949 by the erstwhile Kingdom of Hyderabad and Madras Presidency when the construction began; later, after India's constitution into a republic in 1950, it became a joint project between the governments of Mysore State (now Karnataka) and Hyderabad State (now Telangana). The construction was completed in 1953. The Tungabhadra Dam has withstood the test of time for over 70 years and is expected to well cross many more decades.

The chief architect of the dam was Vepa Krishnamurthy, an engineer from Madras Public Works Department (PWD). He envisioned it as being built with a large contingent of material and manual labour, as best suited to Indian labour availability and employment at that time. The chief contractor for the dam was Venkat Reddy Mulamalla from Konour,    a village  in Mahabubnagar, Telangana.

The famine-ridden region of Rayalseema, then comprising the districts of Bellary, Anantapur, Kurnool and Cuddapah, attracted the attention of British engineers as early as 1860. To relieve the intensity of famines in these districts, proposals were made in 1860 to utilise the waters of the Tungabhadra through a storage reservoir and a system of canals to provide irrigation for the lands. Several agreements were reached for harvesting and imposing restrictions on utilising the Tungabhadra waters. Protracted negotiations and investigations lasted for about eighty years.

In 1860, Sir Arthur Cotton of Madras Presidency originally conceived the Tungabhadra project. His proposals were further modified and developed subsequently, evolving it into a joint scheme with the Kingdom of Hyderabad. N. Paramseswaran Pillai accordingly revised the scheme in 1933. In 1940, Madras ordered a detailed investigation of the scheme. Based on the agreements made, an examination of a number of alternatives was conducted by L. Venkata Krishna Iyer, the then Superintending Engineer, Bellary, and F. M. Dowley, Chief Engineer, both from the kingdom. In 1942, further detailed investigations of the project were done by M. S. Thirumale Iyengar from the presidency. The report he thus submitted was accepted by the Government of Madras with certain modifications fixing the sill level at RL 1550 ft. The June 1944 agreement between Madras and Hyderabad enabled the two governments to finally begin the construction of the Tungabhadra project.

The Tungabhadra Project was formally inaugurated by laying foundation stones on 28 February 1945 by Nawab Azam Jah, the Prince of Berar, on the left side of the dam and by the Baron Sir Arthur Hope, Governor of Madras, on the right. However, owing to India's freedom in 1947, the explosive political unrest in Hyderabad in 1948, and due to differences of opinion in certain technical matters, much headway could not be made until the January of 1949. Madras and Hyderabad engineers were sharply divided on:

The nature of mortar to be used in the construction of the dam,

The design of spillway,

The design of overflow and non-overflow sections of the dam, and

The contraction joints

These differences were referred to a board of engineers chaired by Sir M. Visveswaraya, the former prime minister of the Kingdom of Mysore and the chief architect of the Krishnaraja Sagar Dam in Mysore.

Excavation of the riverbed started in 1947 and masonry construction on 15 April 1949. With the help of a cofferdam constructed earlier, the foundation excavation was continued even during the floods season. The riverbed portion was tackled during the summer of 1950 (1949–50). Masonry in the riverbed blocks started in the 1951, followed by vigorous progress.

By 1952, the canals reached an advance and decisive stage of the construction. On 30 January 1952, the Government of Madras ordered (GO 382) an investigation of the high-level canal. On 15 November 1952, detailed estimates were prepared up to Mile 79/2 covering the reach just before Chinna-Hagari.

A major portion of the construction of the dam was over by the middle of 1953. The low-level canal excavation up to Mile 173 was completed by 1953. The water was led down into the canal on 1 July 1953 to derive partial benefits. Acquisition of lands and villages and rehabilitation of the displaced population from the water spread area of up to 1630 ft contour were completed by the September of 1953. About 90 villages and 54,452 people were affected. By October 1953, the structures were completed, substantially enabling the storage of water in the reservoir up to +1613.00 ft.

In 1954, an investigation of the remaining portion of canal from Mile 79/2 to Mile116/0 was completed and a project report was submitted to the Government of India for approval. The proposals were further reviewed and a final project report was submitted to the Planning Commission for clearance, estimating the costs at Rs. 21.90 crores.

Power canal works started in June 1954 and were completed by May 1957. The reservoir circle was entrusted with the construction of canal works in 1956. The balance portion of the low-level canal from Mile 173 to 203 that had to be excavated by the Government of Andhra Pradesh was completed by the end of March 1957. The balance of the works, namely the spillway, bridge road on the top of the dam, construction of utility tower, manufacture of crest grates for storing water up to 1633 level were completed in all respects by the end of June 1958. In 1958, water was let out up to and inclusive of Distributory 42 to serve an area of about 1.80 lakh acres. The cost of dam and appurtenant works was Rs. 16.96 crores.

The dam forms the biggest reservoir across the Tungabhadra River with 101 tmcft of gross storage capacity at full reservoir level (FRL) 498 m MSL, and a water spread area of 378 square kilometres. The dam is 49.39 meters high above its deepest foundation. The left canals emanating from the reservoir supply water for irrigation to the entirety of Karnataka. The two right bank canals—one at low level and the other at high level—serve irrigation for Karnataka and the Rayalaseema region of Andhra Pradesh. Hydropower units are installed on canal drops. The reservoir water is used to supply water to downstream the barrages Rajolibanda and Sunkesula located on the Tungabhadra River. The identified water use from the project is 220 tmcft by the Krishna Water Disputes Tribunal. Karnataka and Andhra Pradesh got 151 tmcft and 79 tmcft water use entitlement respectively.

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8-1-2023