The cascade system (Ellangawa) is a sophisticated and excellent water management methodology which stores and distributes rainwater, enabling water security and enrichment of interior water resources.
Ellangawa or the cascade system consists of a cluster of small tanks interconnected with an irrigational canal network. This ancient irrigation technology ideally suited to the Dry Zone in Sri Lanka has been now declared a World Agricultural Heritage by the United Nations Food and Agriculture Organization from April 19, 2018. There are around 14,500 functional small tanks, of which 80 percent are part of the cascades. One thousand, two hundred and sixty-two ellanga systems have been identified.
In the Anuradhapura district, two major cascade systems and 2,400 small tanks affiliated to them are being renovated currently under the Wew Gam Pubuduwa programme and another Presidential Secretariat sponsored-programme. The Wew Gam Pubuduwa project or Climate-Resilient Integrated Water Management Project (CRIWMP) aims to develop 325 village tanks in 20 cascades in the Mee Oya, Malwathu Oya and Yan Oya river basins.
The national programme for small tank renovation is being implemented by the Sri Lanka Army, on the instructions of President Maithripala Sirisena and under the supervision of the Presidential Secretariat. The programmes were inaugurated recently in the Mahawilachchiya and Nochchiyagama Divisional Secretariats.
The President commissioned the restoration work of the Dunumadalawa cascade which consists of eight tanks, namely Nabadagasdigiliya, Helambawewa, Mahamillagollewa, Ihala Millagollewa, Ihalathambawewa, Galahitiyawa, Dunumadalawa and Ihala Ethawewa. The construction work of this project is in progress and 40 percent of restoration work is complete.
Once the Dunumadalawa cascade system renovation is over, renovation of the Ihala Galkiriyagama, Diulwewa, Pahala Galkiriyagama, Siyambalaketiyawa, Ihalakoongasdigiliya, Lenawewa, Kimbulapitiya, Naiwewa and Elapathgama tanks which come under the Ambagahawewa cascade system in the Nochchiyagama Divisional Secretariat will begin.
Anuradhapura Government Agent R.M. Wanninayake said that Rs. 70 million has been allocated for the renovation of the Dunumadalawa cascade system. Programme Coordinator Major Bandula Jayasekara of the Army Engineer Brigade entrusted with the construction work of the project, said the Army will ensure quality of the renovation work, rather than merely accelerating the project. Government Agent Wanninayake told the Daily News at the end of a recent observation tour of the Nabadagasdigiliya worksite, that the ancient sophisticated irrigation technology thwarted any possible damage from floods or drought in the Dry Zone.
“Under excellent water management and security techniques, we plan to provide irrigational water facilities to at least 10,000 acres from the two cascade systems. It has been observed that there are tanks which have not been repaired in the last five centuries,” the Government Agent said.
It is learnt that the Nochchiyagama and Mahawilachchiya areas were the worst affected during the drought which prevailed in the Anuradhapura district for nearly two years.
Under this programme,renovation of the cascade system of the Panduwasnuwara-West Kotakimbulagala Anicuit (Amuna), Kanuketiya Wewa, Thoranegedara Wewa, Hindagaha Wewa, Kahatawilagedara, Gonewa Wewa, Perilikadawala, Polathegedara, Gamawewa, Aluthwewa, Katukumbura, Kandewatta, Galkadulla, Karambe Wewa and Kirimetiyawa small tanks are in progress.
The CRIWMP or Wew Gam Pubuduwa project is funded by the UN’s Green Climate Fund with US$ 38.8 million as an outright grant, with the government investing US$ 14 million. Under Phase I of the project, 325 tanks in 20 cascades in the Mee Oya, Malwathu Oya and Yan Oya river basins will be fully renovated. Under Phase II, it has been planned to enhance decentralised water supply and management solutions to provide access to safe drinking water.
It is envisaged to establish 35 community water supply systems, 125 advanced filtration systems and 4,000 rainwater harvesting systems under Phase II and Phase III. It is also planned to strengthen climate and hydrology observing forecast and water management systems to enhance the adaptive capacity of smallholder farmer families to droughts and floods.
A CRIWMP spokesman told the Daily News that the programme covers districts such as Anuradhapura, Polonnaruwa, Kurunegala, Puttalam, Trincomalee, Vavuniya and Mannar. There are 770,500 direct and 1,179,874 indirect beneficiaries in these seven districts. The project has been implemented from 2017 to 2024. River basins such as Malwathu Oya, Mee Oya and Yan Oya with watersheds situated almost entirely in the Dry Zone have been selected.
Tank clusters or the cascade systems which have been selected under the CRIWMP for renovation in the Anuradhapura district are Palugaswewa, Siwalakulama, Bandara Kumbukwewa, Thuduwakkaikulam, Rathmale, Mottapeththewa, Diwulwewa, Aluth Halmillewa with 122 rural tanks affiliated to them. The number of cascade systems which come under the project is eight with 116 village tanks in the Kurunegala, Puttalam, Vavuniya and Mannar districts.
The CRIWMP or the Wew Gam Pubuduwa project is implemented under the auspices of the Mahaweli Development and Environment Ministry with the support of the United Nations Development Programme (UNDP). The Agrarian Development Department, the National Community Water Supply Department, the Agriculture Department, the National Water Supply and Drainage Board and the Disaster Management Ministry are the government partners involved in the implementation of the projects.
There have been a number of tank renovation, rehabilitation and restoration projects implemented in the country. But experts point out that irresponsible renovation methodologies and techniques used to renovate dilapidated tanks have caused heavy damage as the principles of the cascade system are not preserved, but underestimated. It is observed that most of the tank renovation projects are politically motivated, merely heeding to the requests of the stalwarts and always only one tank out of a cluster of tanks is renovated, thus damaging and complicating the technology of tank-to-tank water flow.
The UN’s Green Climate Fund established in 2010 has been the leading international agency which provides funds and grants for projects meant for minimising the climate variability and strengthening the resilience of low-income smallholder farmers for enhancing livelihood empowerment. The UNDP has been a development partner in Sri Lanka for the last five decades, helping to enhance sustainable development and poverty alleviation, and acts as the authorised agency of the Green Climate Fund in Sri Lanka. The UNDP provides the technological assistance in the implementation of the CRIWMP.
While implementing the cascade system rehabilitation project, steps are being taken to search for suitable water sources for the installation of the 20 community drinking water projects in the Anuradhapura and Kurunegala districts. In addition to the ongoing tank renovation plans, renovation of 81 small tanks attached to the cascade systems in the Anuradhapura, Puttalam, Kurunegala and Vavuniya districts are under review. At present, the balance work of another 56 tanks in the Anuradhapura and Vavuniya districts is being executed.
