Cabinet decision to divert Kuda Ganga to Hambantota – A flawed decision?


BY Dr. Janaka Ratnasiri

The Cabinet decision

The Cabinet of Ministers at its meeting held on 22.01.2019 has apparently granted approval for a project for preventing floods in the Ratnapura and Kalutara districts, and providing drinking water to the Hambantota district, by diverting Kuda Ganga, which is a tributary of the Kalu Ganga, as announced in the Cabinet Office website. The decision further says that a feasibility study has been carried out to implement the Kalu Ganga development project at an investment of Rs 123 billion, and has decided to call for proposals for Expression of Interest from International Construction Companies which can implement the project with foreign investment, to call for project proposals from eligible construction companies and to appoint a Cabinet Appointed Committee to evaluate the proposals.

Flaws in the decision

This Cabinet decision raises some doubts as to the feasibility of the project. Kuda Ganga described as a tributary of Kalu Ganga commences near Molkawa after the confluence of Kukule Ganga with Maguru Ganga and ends at Mabogoda where it confluences with Kalu Ganga. Though the Cabinet has decided to divert Kuda Ganga, technically it may not be feasible to do so because Kuda Ganga flows at an elevation below 20 m according to Survey Department toposheets. To divert this water, it is necessary to build a large reservoir and the topography there does not appear suitable for that even to a layman like the writer. It is surprising that such a flawed paper has been submitted by officials of the Ministry and got it approved. So, now, international bids are to be called based on this flawed decision.

Another flaw in the Cabinet decision is that though an objective of the project is said to prevent flooding in Ratnapura District, the diversion of Kuda Ganga will not achieve this objective. Flooding of Ratnapura town and its low-lying areas is caused during heavy rain by water surging down Kalu Ganga and Wey Ganga which confluence at Ratnapura town and not by waters flowing down Kuda Ganga which is in the Kalutara District. It appears that the officer who drafted the Cabinet paper does not know his basic geography.

Thirdly, the statement that a feasibility study on Kalu Ganga development has been carried out and according to this study, an investment of LKR 123 billion is required to implement the project. However, this study may not be referring to diverting Kuda Ganga, in view of the non-feasibility of diverting that river as stated above. It may be referring to diverting either Kalu Ganga or Kukule Ganga which has been attempted a few times in the past. If this is the case, the paper is only misleading the Cabinet. Attempts by the writer to get a copy of the annexure to the cabinet paper describing the project from the Ministry to find out which river is planned to be diverted were not successful.

Further, according to the Cabinet decision, this amount of money is to be raised through foreign investments. A foreigner will invest money in a project only if it will bring some return. Does it mean that water to be diverted to Hambantota will be sold to people there enabling the investor to get a return? Or, does the government plan to export the water diverted? What is the rationale for undertaking such a massive project where there are so many uncertainties? What is the urgency for the new minister to submit a poorly drawn up cabinet paper on such a massive project soon after he assumed office without properly understanding its history and verifying the facts?

Previous proposal to divert Kukule Ganga

Proposal to divert surplus Kalu Ganga water to water-deficit Hambantota is not a new one. The initial proposal to divert Kalu Ganga basin water to Hambantota was made more than 50 years ago by an American firm of consultants under the title "Three Basin River Development" covering the three rivers Kalu Ganga, Gin Ganga and Nilwala Ganga, published in 1968. Under the Kalu Ganga basin, the proposal was made to divert water from a large reservoir built across Kukule Ganga. This river commences from hills in the Sinharaja Forest and flows at an elevation more than 200 m. Diverted water is to be taken via a trans-basin canal, comprising both open segments and tunnels, referred to as the South East Dry Zone (SEDZ) canal to be built along the 120 m contour up to Lunugamvehera Reservoir. The report also recommended building a reservoir across Kalu Ganga at Meehitiya, 3 km upstream of Ratnapura Town to control flooding and develop hydro power. However, with priority given for the development of the Mahaweli River Projects in the 1970’s, the Kalu Ganga project was not pursued.

Kalu Ganga development was undertaken in the 1990’s when feasibility studies commenced to build a 100 m high dam across the Kukule Ganga near Kalawana for the purpose of developing hydro power and to take water from the reservoir to Lunugamvehera along the SEDZ canal. The rapid gradient of the river through 200 m elevation over a short distance made it an ideal site for hydropower development. The large reservoir formed with a high dam, however, was found to cause inundation of large extent of land including Kalawana Town with the water reaching the western boundary of the Sinharaja Forest, which was declared as a UNESCO World Heritage site. This prompted many environment organizations to raise objections including affected people in the area.

In view of its serious adverse environmental and social impacts and also considering protests from the public, this proposal has not been pursued, and instead a smaller pond with a 20 m high low dam was built to operate a run-of-the-river hydro power plant of capacity 70 MW, which was commissioned in 2003. Further, the German-based Lahmeyer International, who along with Skanska and Electrowatt formed part of the Skanska International Engineering Consortium (SIEC) that was responsible for planning the dam, found the geology in the area of the head pond unsuitable to build a high dam required for a large reservoir (

Proposal to build a reservoir at Ratnapura

A few years later, the diversion of the Kalu Ganga received renewed attention when the former President Mahinda Rajapaksa was reported to have said at a function of the new administrative complex in Hambantota in March 2006, that he wanted Kalu Ganga diverted to Ruhuna thereby solving two problems in one attempt, referring to the constant recurrence of floods in the Ratnapura and the occurrence of severe droughts in the Hambantota District, (Daily News of 13.03.2006).

Subsequently, several studies on preventing flooding due to spilling of Kalu Ganga waters have been undertaken including a study by a second American team, a Chinese Team, a Japanese team (JICA) and finally an Israel Team. All these teams have considered building a reservoir at Meehitiya to hold back the flood water, with varying sizes and hydro-power capacities along with other alternatives. However, according to Eng. G.T Dharmasena, a former Director General of Irrigation Department, this water cannot be diverted to Hambantota due to the low elevation of the Meehitiya reservoir site thogh it is feasible to have a reservoir there. Therefore, the benefit of Ratnapura reservoir would be for flood protection to Ratnapura city and for hydro power generation, but not for taking water to Hambantota as anticipated in the project (


JICA study on providing flood

protection for Ratnapura

The Japan International Cooperation Agency (JICA) undertook a detailed study on Flood Management Planning for Kelani, Kalu, Gin and Nilwara Rivers and its report was published in March 2009. Part II of the report covered the Kalu Ganga basin which considered four alternatives as described in the Table 1 along with the estimated costs (

The comments made in the JICA report on the proposed alternatives are as follows:

"The reservoir of Malwala dam, which is planned in the upper streams of Kalu River is expected to be 4 km wide (East-West) and 8 km long (North-South). Due to the formulation of the reservoir, many communities will be submerged, which is expected to lead to the occurrence of involuntary resettlement for hundreds of households. Furthermore, the farmlands formulated in the bottom of the valleys, together with the gem mining sites in the river beds will vanish. The partial submerging of a B class national road crossing the area will spread its impact to other districts as well as the adjacent areas of the dam site. Furthermore, other factors that are expected to receive negative impact include; cultural / religious heritage, hydrology, flora/fauna and bio-diversity, landscape, and other factors relevant to construction work, and the overall negative impact of dam construction is expected to be significant. In order to minimize the impact of the dam and reservoir, a resettlement action plan with not only measures for land compensation, but also with clear measures to compensate for factors such as livelihood and economic activities must be prepared and implemented. Such action plan should be prepared based on detailed socio-economic surveys, disclosure of information/participation of local residents. Moreover, consensus on the resettlement action plan must be built with the local residents from the stage of preparation".

"The economic analysis shows that Alternative I (flood bund) is most viable "Overall", whereas "Short" term measures show smaller EIRR than those of Alternative IV (flood control purpose). The result of IEE shows that Alternative I is expected to have minimum negative impact among the four Alternatives. Further, since there is high potential for large scale involuntary resettlement for the Malwala Dam scheme, it was judged difficult to be implemented under present conditions. On the other hand, technical viability of the proposed works is almost equivalent among the four alternatives because the Government of Sri Lanka has experienced implementing similar structural measures and they do not involve any complex conditions and/or restrictions for design and construction phases. Hence, Alternative I was selected for the flood management master plan in the Kalu River basin".

To be Continued
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