Restoring Traditional Cascading Tank Systems: Achievements in the Kapiriggama Cascade

IUCN Cascade Development Project Information Brief No. 8

For enhanced rural livelihoods and environmental services in Sri Lanka

Background

In the past, the village tank cascade — a centuries-old system —provided villagers living in its surrounds with the above suite of life-sustaining ecosystem services, as described above, for their daily needs. However, a range of human-induced activities has degraded the traditionally rich Kapiriggama village tank cascade ecosystem. These direct drivers include pollution (of both surface and groundwater), natural hazards such as droughts and floods, habitat destruction, soil erosion and the over-arching impacts of climate change. There is also the lack of a mechanism for the management of small cascades.

Watershed management, with active participation of relevant communities, has, therefore, become critically important in the face of current threats. Although poverty and other socio-economic factors are indirect drivers of

change, other factors such as the multiplicity of agencies and laws that confound management also contribute to the degradation of cascade systems. Therefore, an integrated, holistic approach is needed.

The ecosystem approach provides such an integrated method, balancing the conservation of biodiversity; its sustainable use; and the equitable sharing of benefits arising from the use of natural resources.

The main goal of the Project was to restore traditional cascading tank systems for enhanced rural livelihoods and environmental services, through the following objectives:

• To carry out scientific restoration of the Kapiriggama village tank cascade tank system;

• To enhance availability of tank water to meet community needs;

• To create awareness about the village tank cascade ecosystem;

• To build capacity on the maintenance of the system, supplementary livelihoods, and soil and water conservation;

• To strengthen the local institutional mechanism in order to ensure sustainable livelihoods and better management of the cascade; and

• To develop a sound knowledge base for tank cascade management.

This brief summarises all the achievements of the Project.

Carrying out scientific restoration of the Kapiriggama village tank cascade tank system

Ecological restoration1

• Two plant nurseries were established. The land for two plant nurseries was donated by two villagers and maintained for the project duration by them. About 7,500 plants from these nurseries were used in the process of restoration.

• The kattakaduwa area was demarcated in six tanks facilitating restoration activities in the future; in 12 tanks, the kattakaduwa was replanted and gaps filled; in encroached areas of the kattakaduwa the vegetation was enriched with economically important crops;

• In four tanks, the vegetation of the yathuru wala was enriched with certain species; and

• In eight tanks, the gasgommana was replanted with the selected species.

Physical restoration2

• Preliminary investigations were carried out on 21 tanks to identify what needed to be done

• Combining the needs of the community and the results of preliminary investigations, work was identified and carried out in 18 tanks;

• This work included restoration of sluices (in 15 tanks), bunds (in 17 tanks), spills (in eight tanks), and distribution canals (in 14 tanks) associated with irrigation systems.

• Other work associated with irrigation structures such as farm turnouts, culverts, canal over-crossings and service paths was also carried out.

• Tank bed surveys were carried out on 20 tanks to understand the existing tank geometry — the shape and size of the tank bed.

• Based on the results, partial desiltation was carried out in five tanks. About 38,000 m3 of silt was removed from five tanks;

• A water management programme was established. • A leak in the toe of the bund in the Puliyankulama

tank was arrested. According to the experience of farmers and technical officers arresting of this leak saves 50% of water in the tank which was lost since 2004.

1 See Brief # 3 for more details2 See Brief # 5 for more details

Enhancing the availability of tank water to meet community needs

• The changes directly benefited about 600 farmers and their families. (Ecosystem restoration and efficient water management in the cascade indirectly benefits a much larger number of individuals in the immediate downstream areas.)

• With these changes, water holding capacity was increased and communities were able to cultivate in both yala and maha seasons.

Creating awareness about the village tank cascade ecosystem

• Four awareness raising programmes were conducted in three schools in the project area (for about 350 students) on the importance of the cascade tank ecosystem and its conservation.

• About 600 books related to the history, ecology, biodiversity and culture of ancient cascade systems were donated to the three schools of the project area. A herbal garden was established in one of the schools.

• Eighteen shramadana programmes were carried out, with the participation of about 700 villagers from ten villages.

• About 110 HSBC staff participated in the ecosystem restoration activities.

• Awareness of 300 community members was raised about Chronic Kidney Disease (CKD) and the means to avoid such illnesses of through agro-chemical free water use combined with dietary means.

Building capacity on the maintenance of the system, supplementary livelihoods, and soil and water conservation

• Capacity building of 58 officers from government institutes was carried out on watershed management, environmental protection, and sustainable agriculture in tank cascade systems;

• More than 250 farmers were trained on the preparation of organic fertilisers and bio-pesticides; and

• One hundred and ninety five farmers and 25 officers were trained on irrigation water management of small tank cascade systems;

• A comprehensive training manual on irrigation water management of small tanks was produced and is freely available at the IUCN website (http://cmsdata.iucn.org/downloads/farmer_training_manual.pdf). This will be useful for officials of related government institutes, trainers, and university students;

• Sustainable agricultural practices — such as organic farming that minimises the use of agro-chemicals; the establishment of soil conservation bunds for erosion control and groundwater recharge; and introducing micro irrigation with eyebrow bund and pitcher system for irrigation water management — were introduced to 33 farmlands for soil and water conservation in the catchment3;

• In addition, organic farming was promoted in 220 home gardens; and

• Traditional seed paddy (450 kg) was distributed among the farmers in the cascade area. Of this, about half was given to 104 individual farmers who cultivate in the command areas of six tanks. The condition was that they return the same quantity of seed paddy, from their yield, free of charge, to another farmer in the project area for expanding the programme. The rest was given to a group of farmers in Konakumbukwewa for cultivating in a common field because of the limitation of water4.

Strengthening the local institutional mechanism in order to ensure sustainable livelihoods and better management of the cascade5

• A Cascade Management Committee was established to bring all stakeholders of cascade resources to one platform, to discuss issues and make decisions on sustainable use and management of the natural resources of the cascade;

• The above is a multi-stakeholder/ multi-disciplinary approach to catchment management; it integrates upstream and downstream users for better management;

• This Cascade Management Committee met five times during the project period. Because this committee lacked the participation of the officials,the following committee was later formed;

• Three Grama Niladhari level committees for the three GN Divisions (Kapiriggama, Konakumbukwewa, Penagama) were established in place of the above.

5 See Brief # 4 for more details

4 See Brief # 7 for more details

3 See Brief # 6 for more details

Jan 2016

For more information contact

Shamen Vidanage, Programme Coordinator, IUCN Sri Lanka Country Office53, Horton Place, Colombo 7, Sri Lankatel: +94-112682418, fax: +94-112682470email: shamen.vidanage@iucn.org; https://www.iucn.org

Photographs: Multi-stakeholder approach to cascade management (Kumudu Herath © IUCN); page 2 left top: Arecanut cultivation in the encroached kattakaduwa in Galkadawala tank, (Kumudu Herath © IUCN); left bottom: Community members engaged in a gasgommana replanting programme (S. M. M. Senavirathna © IUCN); right top; Tank bund and sluice repair at Palugonamariyawa tank (Kumudu Herath © IUCN); right bottom: Partial desiltation of Konakumbukwewa tank (Kumudu Herath © IUCN); page 3 left top: School awareness raising programme held at Konakumbukwewa Maha Vidyalaya (Kumudu Herath © IUCN); left bottom: HSBC Volunteers help farmers in tank restoration, Puliyankulama Tank (Naalin Perera © IUCN); this page above: Collection of data on ethnobiology (Sampath de Alwis Goonatilake © IUCN).

Developing a sound knowledge base for tank cascade management

• Baseline data of the Kapiriggama small tank cascade systems were collected for the following: • Socio-economic data for a sample of 163 households; • Ecological and ethnobiological data of 23 individual tank ecosystems (a database was also established)4; • Tank infrastructure data — such as the inventory of the condition of tank infrastructure — was carried out for 21 tanks; • Tank bed survey data for 20 tanks; • Sediment depth survey data for six tanks; • Soil quality data of the command area of eight tanks (such as soil pH, electrical conductivity, organic matter content, potassium, phosphorous, and drainage capacity); • Water quality data of 238 drinking water sources; and • An agro-meteorological station was established

at the Agrarian Service Centre, Kallanchiya. In addition, 15 rain gauges, 21 depth gauges in tanks, and 13 Parshall flumes5 were established. Farmers were trained to collect and record, on a daily basis, data such as rainfall data, tank water height, and irrigation water issues. Farmers and officials have been trained how to used this collcted information in decision-making related to irrigation water management.

• GIS maps for catchment land use were developed for the entire cascade. These maps included land use of individual tank catchments. Tank boundaries were demarcated on these maps. These maps represent the latest cascade land use as they have been updated using 2015 satellite images. Therefore, they are very useful for the purposes of planning.

• A online map portal has been developed (which can be accessed through the IUCN website). This includes all GIS map layers developed under the project. This allows interested groups — such as Government officials, students, researchers, and individual experts —to use these maps freely.

• Two video documentaries of the project (in Sinhala and English) have been produced. In addition, five short video clips on small tank cascade systems, ecological restoration, soil conservation, partial desiltation and water management have been produced for dissemination of the knowledge gathered and the techniques used in this project.

• Technical notes and associated information briefs have been produced for key topics of the Project. These are available for free use at the IUCN website (https://www.iucn.org/about/union/secretariat/offices/asia/asia_where_work/srilanka/publication/).

• The knowledge material developed under the project will benefit a large range of stakeholders.

Recommendations for the future

• Continue cascade restoration programmes.• Use the information and maps developed under the

project for planning purposes in the future. This can be achieved at Grama Niladhari, Divisional, District, and National levels;

• There is a need for orgnisational strengthening to support cascade level resource management;

• There is a need to improve legal provisions and formulate a mechanism to solve legal issues related to restoration;

• Continue demarcation of tank ecosystems and/or its components for management purposes;

• Use the upstream tank bed area recovered by partial desiltation (of Konakumbukwewa, Massalawa, Peenagana, Maha Kadiyawa, and Puliyankulama ) as pasture land for sustainable animal husbandry; and

• Avoid the approach of rehabilitating individual tanks and instead consider the cascade as an integrated system, and then determine the approach for restoration.

4 See Brief # 2 for more details5 a structure developed to measure surface waters and irrigation flow.