• Latest report tackles nat. environmental challenges including leaks in reservoirs, the flooding of rivers, and the HEC 

Analysing critical issues and proposing practical solutions are crucial for safeguarding community wellbeing and fostering sustainable progress. The recent insights from the Parliamentary Committee on Ways and Means shed light on various environmental challenges affecting communities across Sri Lanka. 

From tackling persistent leaks in the Samanalawewa Dam to addressing the intricate human-elephant conflict (HEC) in Irudeniyaya, the Committee's latest report presents recommendations to reduce risks, bolster resilience, and foster inclusive growth. Through a thorough examination of these issues, the Committee emphasises the importance of collaborative efforts and data driven strategies to effectively tackle these challenges.

Samanalawewa Reservoir

The Samanalawewa Reservoir, constructed in 1992, receives water from both Belihuloya and the Walawe River, and the Reservoir has been facing persistent leakage related issues for the past 30 years. Drought-related conditions last year (in 2023) have revealed routes of potential leakages, prompting scientific investigations. Experts have emphasised the urgent need to address the leakages to prevent a potential disaster, urging to ensure the safety of downstream communities. The primary concern is to ensure the safety of the Reservoir and the people living in the vast downstream expanse of the Dam, who live under constant threat. 

According to the report, the leakage of the Samanalawewa Reservoir is found to be in the right bank of the Samanalawewa due to limestone present in the geological area dissolving and creating a sinkhole in the bank, and it was first reported in 1992. In 2012, international consultation was obtained to address the leakage from the International Commission on Large Dams (ICOLD). They recommended repairing the leakage in the Dam and evacuating the people living in the area as an immediate measure. A two kilometres tunnel was grouted and sealed to prevent the leakage. 

However, research conducted by the Peradeniya University has reported that 60% of the leakage is occurring from the tunnel access area. The ‘Khondalite’ mineral present in the bank has dissolved and nearly 2.2 tonnes of it have passed through the leakage, creating a large sinkhole in the right bank of the Reservoir. The Kalthota irrigation area, spanning approximately 3,000 hectares, relies on water from the Reservoir. Initially, this region received water exclusively during a specific season, as dictated by the operational schedule of the Samanalawewa Power Station. However, due to existing leakage-related issues, the Kalthota area can now be irrigated all year round. 

Additionally, harnessing water from the leakage has led to the establishment of two small scale power stations in the region. One, with a 1.2 megawatt capacity, is owned by the Ceylon Electricity Board (CEB), while the other is the Mulgama Mini Hydro Power Plant, owned by the private sector. The National Building Research Organisation (NBRO), in response to the request made by the Peradeniya University, has undertaken a geographical survey of the right bank of the Reservoir. The findings indicate that there is currently no immediate threat to the Samanalawewa Dam. However, it is emphasised that if the issue persists over an extended period, it could potentially lead to a catastrophic event. If the leakage is repaired and the Reservoir is fully filled, more electricity could be generated from the main Samanalawewa Power Station than the power generated from the capacities of both the small power stations combined.

Considering the issue, the Committee, in its latest report, recommended thoroughly assessing the leakage and taking measures to prepare a risk mitigation plan. “Any measure to rectify the leakage has to be done after a thorough study, as many repairs done previously were not successful due to the large pressure from the water body on the Samanalawewa bank.” 

The introduction of a real time monitoring and warning system to alert the people of the area of the Samanalawewa Dam in any danger was also recommended as any leakage would, as per the report, affect people belonging to nearly 2,000 families in 12 Grama Niladhari (GN) Divisions and a large extent of cultivated lands. “Formulating a comprehensive disaster management programme to address the Samanalawewa Dam leakage is needed. This should involve close coordination with the relevant stakeholders to prepare for potential future disasters as warned by the Irrigation Department and geologists.” The Committee further directed the CEB, which owns the Samanalawewa Reservoir to provide a permanent solution to the leakage.

Human-elephant conflict in Irudeniyaya

The report further stated that land plots between the Hakwatunawa Reservoir and its upper catchment area are acquired by the inhabitants of Irudeniyaya and that they are cultivating green beans on a large extent of land. Noting that the then Government awarded land acquired from the Kahalle Pallekele Sanctuary to inhabitants of Irudeniyaya, complying with the land policy of the country, the Committee stated that a conflict has arisen as 18 families, who obtained land near the Hakwatunawa Reservoir, are allegedly obstructing elephants' access to the Reservoir, their crucial water source. Although the Government is ready to provide alternative land from the Kahalle Pallekele Sanctuary to those residents, it is mentioned that the families are not accepting this proposal. Since constructing an elephant corridor is challenging due to local residents often misconstruing it as a wildlife boundary, the Committee highlighted that support from the political authorities is crucial to reach a consensus with the inhabitants of the area. Towards the resolution of the issue, the Committee has recommended awarding land plots to 18 families in the Irudeniyaya area from the Kahalle Pallekele Sanctuary and building the artificial elephant corridor immediately. The District Coordinating Committee of Kurunegala, the District Secretary, the Director General of Wildlife Conservation and the inhabitants of Irudeniyaya area have been urged to reach a consensus on the issue.

Flooding in Colombo

In the report, the Committee stated that the Colombo Municipal Council (CMC) had identified 45 major flood prone areas and 20 major flooding locations. In response to the issue, the Committee recommended undertaking a thorough stability assessment of the bank along the Kelani River in the Ambatale area to mitigate potential risks and ensure safety. Further investigation and preventive measures have been suggested to address any potential hazards. Pointing out the importance of developing and implementing effective solutions to tackle the flash flood related challenges and to mitigate the issues associated with sudden and intense flooding, another recommendation has been made to clear the drainage system and secondary canals of the Colombo City by removing all leakages.

Nilwala River flooding

The Committee has outlined in its report that the flooding of the Nilwala River in 2023 was compounded mainly due to the salinity barrier constructed to ensure the supply of safe and clean drinking water, adverse weather conditions resulting in heavy rainfall, silt deposition in the Nilwala Basin, the persistence of the two barriers due to the non-removal of an unrestrained sand barrier along with the salinity barrier, insufficient funds and equipment for silt removal and the maintenance of canals and tributaries of the River in turn hindering proper upkeep, the retention of alternative temporary roads established during expressway construction, and the inadequacy of fuel for the pumping stations responsible for releasing rainwater into the River within the Nilwala protected area. The primary factor contributing significantly to the extended flooding of the Nilwala River in 2023, as per the Committee report, was the failure to remove sand barriers, which were annually installed at a cost of Rs. 10 million. 

Although the National Water Supply and Drainage Board (NWSDB) allocated funds to the Irrigation Department for the removal of these barriers, the insufficient availability of machinery is said to have hindered their complete removal. “Prior to the construction of the salinity barrier, the Central Environmental Authority (CEA) conducted an Environmental Impact Assessment (EIA) in 2017, and the Irrigation Department and the Lanka Hydraulic Institute conducted an assessment on flood mitigation,” the Committee mentioned, claiming that the NWSDB has not implemented the recommendations and guidelines of the feasibility studies conducted on the construction of the salinity barrier. The report mentioned that the prolonged flooding of the Nilwala River in 2023 resulted in severe repercussions for farmers, with crop losses spanning nine cultivation seasons, as the inundated water persisted for a duration of almost three months without drainage. 

In order to resolve the issue, the Committee recommended initiating a feasibility study aimed at safeguarding the Matara City and its adjacent suburbs from floods, while also addressing the provision of drinking water in collaboration with key stakeholders such as the Central Engineering Consultancy Bureau, the NWSDB, the Irrigation Department, the Sri Lanka Land Development Corporation (SLLDC), and other pertinent institutions. Eliminating the sand barrier entirely and conducting dredging in the Nilwala River have been recommended as temporary measures. In the event of machinery related shortages, the Committee suggested that the relevant institutions seek assistance from the SLLDC to facilitate this process. Noting that culverts and canals along the Nilwala River have been obstructed and left unmaintained during the period of expressway construction and other development activities, the Committee recommended repairing or removing blockages in such. Conducting a feasibility study for the construction of three proposed Reservoirs, namely the Digili Oya, the Batuwita Ara and the Aparekka Ara, aimed at preventing flooding and meeting the drinking water requirements of the Matara City and its surrounding areas, and the provision of compensation to farmers affected by crop losses in Matara due to flooding, have also been proposed by the Committee.