Thursday, 21 April 2022

Mahaweli Development Project

Mahaweli Development Project
Mahaweli Development Project (Sinhala: මහවැලි සංවර්ධන ව්‍යාපෘතිය) is the largest irrigation-based multipurpose development program in Sri Lanka to date and one of the largest agriculture-related programs in the world (Gunatilake, 1991; Paranage, 2019). Carried out on water resources of the Mahaweli Ganga and allied six river basins, the project was mainly implemented in North-Central Sri Lanka, covering a large part of the country's dry zone (Azmi, 2007; Mahaweli Statistical Hand Book, 2021). The project's main purposes included reducing rural unemployment, decreasing population pressure in the wet zone, providing land for landless farmers, achieving self-sufficiency in paddy production, reducing poverty, and generating hydropower.

The Master Plan
Mahaweli Ganga is the longest river in the country and it conveys the largest volume of water in Sri Lanka amounting to one-seventh of the total runoff (Hewavisenthi, 1992). Its basin which extends in an area of about 10,320 km2 is equivalent to 15% of the country’s land area and is the largest river basin (Hewavisenthi, 1992).

The step to develop the resources of Mahaweli Ganga was taken place when the Government of Sri Lanka (then Ceylon) and the United States Operation Mission to Ceylon entered into a project agreement on 7 February 1958 which provided for a joint program in water resource planning with special emphasis on the preparation of a plan for the total development of the water resources of the Mahaweli Ganga Basin (Gunatilake, 1991). This was followed by a comprehensive study of the Mahaweli Ganga basin by a team of UNDP (United Nations Development Programme), FAO (Food and Agriculture Organization) and Sri Lanka who successfully identified several sites suitable for irrigation and building dams including hydropower generation (Gunatilake, 1991). The Master Plan prepared by them was released under the title "Mahaweli Ganga Irrigation and Hydro-power Survey of 1969" (Gunatilake, 1991).

Mahaweli Development Project (MDP)
The purposed period of the project, as in the Master Plan, was 30 years and at the time, it was known as the largest national development project ever to be undertaken in the country (Azmi, 2007; Gunatilake, 1991; Paranage, 2019). The plan included the construction of a series of reservoirs on the Mahaweli Ganga and its tributaries and neighbours such as Amban Ganga, Maduru Oya, Kala Oya and Malwathu Oya (Gunatilake, 1991).

The first phase of the plan consisted of the construction of the Polgolla-Bowatenna Complex, the Victoria-Minipe Diversion and the Moragahakanda Reservoir and the generation of hydropower (Gunatilake, 1991). The second phase proposed the development of land using the waters of Victoria and Moragahakanda reservoirs and the installation of hydropower. The third phase included the construction of the Kotmale and Randenigala reservoirs and the development of other tributaries of the Amban Ganga and the generation of hydropower (Gunatilake, 1991).

The work of the first project of the plan was inaugurated on 28 February 1970 with Polgolla-Bowatenna Diversion by Prime Minister Dudley Senanayaka (Gunatilake, 1991). The project was completed by 1976, giving its benefits to the people of the Anuradhapura, Polonnaruwa and Trincomalee districts (Gunatilake, 1991). The development of the Kandalama and Kalawewa areas (Area H) was also carried out during this period by establishing new townships, villages, hamlets, hospitals and schools (Gunatilake, 1991).

Accelerated Mahaweli Development Project (AMDP)
Due to the high unemployment rate, rolling power cuts and other factors, the Sri Lankan economy had ground to a virtual standstill by 1977 (Gunatilake, 1991). The new government that came to power in 1977 decided on 12 October 1977 to accelerate the project to find immediate solutions to the socio-economic problems that were prevailing in the country at that time (Azmi, 2007; Hewavisenthi, 1992).  The project was renamed the Accelerated Mahaweli Development Project (AMDP) and it included only the major projects of the Master Plan to be completed within 6 years (Gunatilake, 1991). Accordingly, the Ministry of Mahaweli Development was set up to implement the decisions of the government to accelerate the Mahaweli Programme (Gunatilake, 1991).

Mahaweli Authority, which was set up by the Ministry of the Mahaweli Development in 1979, was responsible for planning and implementing the project. The chief agencies executing the programme were the Mahaweli Development Board and the Central Engineering Consultancy Bureau (Gunatilake, 1991). The other organizations involved in the project included the Department of Irrigation, the Survey Department, and the River Valleys Development Board (Gunatilake, 1991). 

The AMDP began with the intention of completing three main components; i) the headworks of Victoria, Kotmale, Maduru Oya and Randenigala reservoirs, ii) the downstream engineering works dealing with diversion works and, iii) the irrigation and development of downstream areas which included the lands in System B, C, A, D, H,  and G (Gunatilake, 1991). More than 140,000 families were resettled under the AMDP by giving them a certain amount of irrigated lowland for cultivation and land for a home garden (Azmi, 2007).

Mahaweli irrigation systems: The Mahaweli system supplies water to several existing and new irrigation areas within the Mahaweli and Amban Ganga basins and adjacent basins of Maduru Oya, Kala Oya, Malwatu Oya, and Yan Oya (Hewavisenthi, 1992). These irrigation areas are designated by alphabetic letters, A to H (Hewavisenthi, 1992).

Foreign assistance
Nearly 70% of the funding for the headworks of the project was through foreign sources (Gunatilake, 1991). The Government of the United Kingdom supported the Victoria Project while the Canadian Government financed the Maduru Oya Project (Gunatilake, 1991). The Randenigala Project was supported by the Government of Germany and Sweden Government helped the Kotmale Project (Gunatilake, 1991). The United State Government, Japan, Saudi Arabia, Kuwait and several international agencies financed the development works of the downstream areas (Gunatilake, 1991).

Mahaweli major dams and reservoirs

No. The Dam Specifications Remarks
1 Victoria Dam
(Kandy/Nuwara Eliya districts)
Dam type: Double curvature concrete arch of 122 m high & 520 m long (crest).
Gross storage capacity: 722 MCM.
Generating capacity: 70x3 MW.
The construction work of the project was commenced on 23 March 1980. Works of the dam & tunnel were begun on 10 April 1980. The project was commissioned on 12 April 1985.
2 Randenigala Dam
(Kandy District)
Dam type: Rock fill with a central rock impervious earth core. 94 m in height & 485 m in length (crest).
Gross storage capacity: 802 MCM.
Generating capacity: 63x2 MW.
The reservoir was impounded on 23 March 1986.
3 Rantembe Dam
(Kandy/Badulla districts)
Dam type: Concrete-gravity dam of 42 m high and 415 m long (crest).
Gross storage capacity: 6 MCM.
Generating capacity: 24.5x2 MW.
The work of the project was commissioned on 23 March 1986. The power complex was commissioned on 26 May 1990.
4 Kotmale Dam
(Nuwara Eliya District)
Dam type: Rock fill with upstream concrete membrane. 87 m in height & 600 m in length (crest).
Gross storage capacity: 171 MCM.
Generating capacity: 67x3 MW.
The feasibility study commenced in May 1973. Construction work was started on 4 February 1979. The reservoir was impounded on 17 November 1984. The project was commissioned on 23 August 1985.
5 Polgolla Dam
(Kandy District)
Dam type: Low concrete weir with gated spillway & bridge. 15 m in height & 144 m in length (crest).
Gross storage capacity: 4 MCM.
Generating capacity: 20x2 MW.
The Mahaweli Ganga diversion at Polgolla commissioned on 30 September 1968. The Project was inaugurated on 28 February 1970. Construction work of the complex started on 10 May 1970.
6 Bowatenna Dam
(Matale District)
Dam type: Earth & concrete. 29 m in height & 327 m in length (crest).
Gross storage capacity: 4 MCM.
Generating capacity: 20x2 MW.
The project was inaugurated on 30 March 1973. 
7 Ulhitiya/Rathkinda
(Ampara/Badulla districts)
Dam type: Earth fill. 25 m in height & 282 m in length (crest).
Gross storage capacity: 145 MCM.
Construction work of Ulhitiya commenced on 30 January 1978.
8Maduru Oya Dam
(Polonnaruwa District)
Dam type: Rock fill with center core. 40 m in height & 1,090 m in length (crest).
Gross storage capacity: 597 MCM.
Generating capacity: 2.5x2 MW.
The project was commissioned on 14 August 1978.
9 Dambulu Oya Dam
(Matale District)
Dam type: Homogeneous earth fill. 12 m in height & 1,600 m in length (crest).
Gross storage capacity: 12 MCM.
Generating capacity: 2 MW.

10 Kandalama Wewa
(Matale District)
Dam type: Homogeneous earth fill. 21 m in height & 1,700 m in length (crest).
Gross storage capacity: 34 MCM.

11 Kala Wewa
(Anuradhapura District)
Dam type: Homogeneous earth fill. 15 m in height & 6,800 m in length (crest).
Gross storage capacity: 104 MCM.
Jaya Ganga sluice was opened on 30 October 1979.
12 Minipe Anicut
(Badulla District)
Dam type: concrete gravity-orgee. 9 m in height & 226 m in length (crest).

13 Loggal Oya Dam
(Badulla District)
Dam type: Earth fill. 28 m in height & 2,250 m in length (crest).
Gross storage capacity: 48 MCM.

14 Heppola Oya Dam
(Badulla District)
Dam type: Earth fill. 19 m in height & 1,632 m in length (crest).
Gross storage capacity: 13 MCM.
Generating capacity: 4.775 MW.

15 Diyabana Oya Dam
(Badulla District)
Dam type: Earth fill. 8 m in height & 825 m in length (crest).
Gross storage capacity: 1 MCM.

16Chandrika Wewa
(Ratnapura District)
Dam type: Earth fill. 19 m in height & 2,500 m in length (crest).
Gross storage capacity: 28 MCM.

17 Moragahakanda Dam (main)
(Matale District)
Dam type: Earth core rock fill. 59 m in height & 471 m in length (crest).
Gross storage capacity: 558 MCM.
Generating capacity: (2x7.5) + (2x5) MW.
The project was inaugurated on 25 January 2007. Opened for the reservoir for the public on 8 January 2018.
18 Udawalawa Dam
(Ratnapura/Monaragala districts)
Dam type: Earth fill. 37 m in height & 4,000 m in length (crest).
Gross storage capacity: 269 MCM.
Generating capacity: 2x3 MW.
Uda Walawa Left Bank Phase II was commissioned in 1999. The Left Bank Phase II was completed on 31 December 2008.
19 Kalu Ganga Dam (main)
(Matale District)
Dam type: Earth core rock fill. 68 m in height & 659 m in length (crest).
Gross storage capacity: 248 MCM.
The construction work of the main dam was commenced in April 2015.
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References
1) Azmi, F., 2007. Changing livelihoods among the second and third generations of settlers in System H of the Accelerated Mahaweli Development Project (AMDP) in Sri Lanka. Norsk Geografisk Tidsskrift–Norwegian Journal of Geography, 61(1), pp.1-12.
2) Gunatilake, K.H.S., 1991. The Mahaweli development project-an overview. Prof. E.O.E. Pereira Commemoration Lecture 1991. Engineer. pp.16-28.
3) Hewavisenthi, A.C. De S., 1992. Mahaweli water resources project. Water international, 17(1), pp.33-43.
4) Mahaweli Statistical Hand Book, 2021. Mahaweli Authority of Sri Lanka. pp.6-8.
5) Paranage, K., 2019. The Mahaweli Development Project and the ‘rendering technical agrarian development in Sri Lanka. Heliyon, 5(6). p.e01811.


This page was last updated on 16 May 2022
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