Rehabilitation of Small Tank Catchment Areas
Catchment area of the tank feeding the tanks
The hydraulic civilization of the ancient Sri Lanka, built many small tanks in the Dry Zone of Sri Lanka to retain water to be used in the dry season for agriculture, domestic consumption and for the domestic animals. These tanks formed a seperate micro environment.
Anuradhapura District (The Dry Zone District of Anuradhapura comes within the North Central Province in Sri Lanka)
This area is part of the lowest peneplain moving from the coast and altitude is 0-125msl. However, there are undulating parts and isolated mountains within the area.|
Specific Soil Type: Reddish Brown
The temperature falls within the range of 25C-37C and the annual rainfall is less than 1500mm.The rainfall is restricted to 3-4 months and the remaining months experiences dry weather.The hydraulic civilization in these areas built small tank systems to retain water for the dry season.
The main sources of income is the income received from agriculture. Agricultural practices include paddy and vegetable crop cultivation. Paddy is grown in lowlands with water from the tank and vegetables are grown in "Chenas" (slash and burn)in highlands.
Land tenure system in these areas has led to land fragmentation, specially paddy fields. The paddy lands have been fragmented to the extent of being economically non-viable. This has become a bottleneck in introducing new agricultural practices.
These areas are predominantly agricultural areas and the average income is far below the per capita GDP, which is US$ 2050 in 2009. Contribution to GDP in these district in the North Central Province is only 2.7% and therefore, these people receive minimum income (less than 100US$ a month)|
The practice can be considered "best" due to the following.
1). Stakeholder participation ensured 2). Minimum cost 3).Environment friendly 4). It has multiple effects 5). Could be early replicated 6). Generates sense of ownership.
1). Further degradation of the catchment area and soil erosion 2). Lowering of the water retention capacity of the tank 3). Deterioration of the environment and associated ecosystem services 4). Water scarecity in the dry season 5).Lowering of farmer income and partly malnutrition
6). Conservation of the micro environment
Soil erosion due to clearing of the catchment area for cultivation and other purposes was the main environmental issue. The soil erosion could be mitigated through the adoption of the strategies given in this document.
1). To mitigate soil erosion in the catchment area of the tank
2). To restore the catchment area
3). To restore micro-environment of the area
4). To avoid water security
Tree planting in the catchment area with inadequate spaces and adoption of soil conservation measures
Through the adoption of soil erosion practices, and tree planting, it was expected that water retention capacity will increase and the natural environment retain excessive water and release gradually. |
Adoption of conservation practices and awareness on environmental conservation to farmers
With the interaction of activities referred to above 1 and 2, it was expected to restore the micro-environment in the area. Minimal disturbance to the natural environment was the key "slogan" in this exercise.|
The activity comprises a mix of activities;
1). Land use planning 2). Identification of suitable crop species, 3). Adoption of soil conservation measures
4). Obtaining stakeholder support. |
The success of the activity was a result of the adoption of a scientific approach for conservation of the catchment that is using land use planning for optimal utilization of land.
Ministry of Environment
Partners 1). Land Use Policy Planners
2). Forest Department
3). Farmer Organizations
1). Farmer Organizations
The farmers have indigenous knowledge and it has optimally used in this exercise. They were able to assist in demarcating areas, identification of plant species, adoption of soil conservation measures.There were, the real "implementers" of the activities. |
The ecosystem will provide shelter for wild fauna and protect animal biodiversity.
With the ecosystem restoration, agricultural production will be increased, increasing productivity of agricultural lands. At the same time, the ecosystem will be restored and nutrient and energy transfers within the ecosystem will be re-established. |
The improved micro-environment in the area will provide ecosystem services rapid. As a result, the tank system will receive continuous supply of water thereby increasing agricultural productivity. |
As described in the text, the catchment area restoration will allow to re-generate the system as it was. The micro-environment will start producing ecosystem services.This is extremely important since, about 8 months remain dry in these areas.|
The increased income will increase the purchasing capacity of framers and will increase Physical Quality of Life (PQL) and reduce Human Poverty Index (HPI) and increase their socio - economic level.
The agricultural production will generate more incomes to the farmers thereby uplifting their standard of living
The increase in the water retention capacity of the tank will reduce the threat of floods in the lower parts and/or in the tanks located in the down stream. Sometimes tanks are located as a chain, the upper ones feeding the lower ones.|
The ecosystem will have a "spread effect". Other neighboring villagers will start thinking replicating the experiences.
Sri Lanka is one of the biodiversity hotspots in the world. Since many floral species and faunal spp. are endemic to Sri Lanka, there is possibility of these species being destroyed, if the catchment area is disturbed |
To serve other districts
The strong commitment from the government side was another reason for the success. The Ministry officials, forest officers,and Officers of the Land Use Policy Planning Department of the district were highly involved and dedicated for the activity. |
The main reason for the success this initiative is the stakeholder participation. In this context, the farmer organization acted as implementer of the programme.They were able to obtain support of all the framers and their contribution was in the form of labour.
The end- results could be seen in the short run, preferably with a period of 1-2 years. However, it takes years for this
ecosystem to be restored. |
1). Stakeholder participation is essential for the success of country based activities. Their involvement should be obtained for planning, implementation and monitoring of projects.2). Top-down approach is unsuccessful in activities where strong country participation is needed
3). Through a well coordinated approach and guidance, we can develop country leaders. |
1). Costs could be minimized with strong stakeholder participation. 2).Impacts of these projects cannot be measured properly on cost- benefit analysis eg. aesthetic value of a tank system and associated environment and fresh air. 3). However, finance becomes a limiting factor. Therefore, mobilization of resources is necessary |
1). Adoption of scientific approaches in every activity is essential. In this case, the project became successful since the area was mapped using modern land use planning techniques 2). The technology should be people friendly and people centric. Then the technology is well received by the community 3). Technology should be simple to the extent possible to be understood by the people.