Farmers dig nature`s dams

30/04/1994
Down To Earth

Farmers dig nature`s dams FOR nearly 400 years, Nepal has been using an indigenous irrigation system fortified remarkably without the help of cement or girders. The farmers in the Gorkha, Palpa and Rupandehi districts have built over centuries a complex network of canals and weirs using only boulders, tree branches, soil and wood to divert the waters from streams and rivers.

Two canals in the Palpa district -- the Chherlung Thulo Kulo and the Argali Raj Kulo -- draw their waters from the streams Barangdi Khola and Kurung Khola respectively. They irrigate 88 ha, benefiting 263 farmers. The Chhattis Mauja Irrigation System (CMIS), located in Rupandehi district, receives water from the Tinao river, a perennial source, and serves over 3,500 ha. Water from the Kharkhola river operates three water mills, a water turbine and 32 farmer-managed irrigation systems in Gorkha district.

Perfected over time
These irrigation networks are the outcome of indigenous knowledge and technology perfected over centuries. Small dams, tunnels and the unique saanchos -- proportioning wood weirs for water allocation and distribution -- are built skilfully with local material. Hollowed out logs are used as conduits for transporting water across gullies.

The oldest irrigation network in the three districts is Argali Raj Kulo, founded by Raja Mani Mukunda Sen in the first half of the 16th century. The CMIS was initially constructed by the local people between 1846 and 1863. The Kharkhola system is believed to be over 100 years old; construction on the Thulo Kulo canal, on the other hand, began in 1928.

In areas of water scarcity, water rights exist independent of land rights; a landless person with access to water is free to sell it, as happens in areas irrigated by the Chherlung Thulo and the Argali Raj Kulo canals. The CMIS also raises its own resources through the sale of water rights. Joint participation entails that a village allotted five units of water sends five people to work on the canal. At the Kharkhola irrigation system, for instance, money for canal maintenance is raised from users according to the size of their farms.

In erosion-prone zones along the canals, bamboo and local bushes are planted for slope and gully stabilisation. In Argali and Chherlung, several canals were dug behind large boulders at the edge of the stream in order to limit the water entering the canals during floods. Small dams made of rocks and tree trunks are used to divert the streams. And leaks in the dams are plugged with leaves, brush and clay.

The canals are made with infinite care. First, a small canal is constructed and water periodically diverted into it to check the slope. The alignment of the proposed canal is thus fixed. It can then be enlarged without the danger of an uphill recoil.

Experienced tunnel-makers called agris design tunnels running parallel to the surface and a metre or two into the hillside. Windows for light and access are made every 4 to 6 metres. To break harder rock, a fire is got going flush against the rock; then, water is poured onto it so that the rock cracks without creating big fissures. Only hammers and chisels are used inside the tunnels that are cut from each side of the hill.

Water allocation and distribution is through wooden saanchos. Water scarcity is handled by distributing water by rotation, called rotational irrigation.

Each time a saancho is put into operation, all the farmers meet to inspect and approve it. Thereafter, no one is allowed to tamper with it or to raise any complaints about its accuracy. If water supply is limited, the saancho can be simply removed or used as a gate. In Chherlung and Argali, water supply is often low and rotational irrigation has to be practised.

Water delivery is timed by an innovative water clock: a large cooking pan filled with water and a small bowl with a tiny hole at the bottom. The empty bowl is set on the water in the large pan where it slowly fills with water. When it sinks, one unit of time has elapsed.

The CMIS has detailed rules for the allocation and distribution of water to the rice crop -- the main crop of the region. Water rotation is necessary only in times of scarcity and it is the village meth mukhtiyar (system level manager) who decides on the quantity of water to be assigned to each user. Likewise, under the Kharkhola system, water is shared on a rotational basis during a dry spell.

A local irrigation principle used extensively in Argali is the construction of numerous parallel canals from the same stream to serve contiguous land holdings. It enables the construction of new canals without jeopardising existing ones. Another advantage is that a small canal is cheaper and easier to cut along a steep hillside. Water lost due to seepage from one canal can be picked up by the adjacent lower canal; the only irrecoverable seepage, thus, is from the lowest canal.

Under the Raj Kulo system, farmers meet and accounts are presented, and a work schedule for the annual maintenance work is set. At Thulo Kulo meetings, attendance is compulsory for all members and those who are absent are fined. Members are divided into seven groups, each named for a different day of the week. A group is responsible for operating the system on the day for which it is named. All farmers cultivating khet fields (lowland fields) belong to the Raj Kulo organisation. A 6-member committee is elected to look after the canal system. A mukhiya (chief) chairs the meetings, a sachiv (secretary) looks after records and a pahiro jaachne (hill inspector) checks and assesses landslides. Two people patrol the canal and check for leaks and damages.

The CMIS, in contrast, is a much larger canal network. The entire command area has been divided into 9 regions, and the chairperson of each region becomes a member of the Chhattis Mauja Irrigation Committee.

Then there are 9 regional committees consisting of 3 to 10 villages, and, finally, a village level committee headed by a mukhtiyar. Messengers are appointed to help these 3 committees communicate with each other. The mukhtiyar is the key figure and collects fines, fixes water rotation schedules and assigns work for canal maintenance.

Local grnius
Farmers under the Kharkhola irrigation system have locally organised themselves into Water User Groups. Some of these organisations are several generations old. Sometimes there are no documented rules and regulations but all users contribute labour and material for repair and maintenance. Users who do not cooperate are fined or penalised.

In areas where user groups are well-organised and aware of their rights, irrigation systems function to near perfection. Informal rules work better than formal ones. The farmers here have demonstrated that they can create an extensive and complex organisation to manage their irrigation systems. Farmers contribute resources for the upkeep of their system, and to construct canals and tunnels. In Argali and Chherlung, farmers also achieved high agricultural production. Three irrigated crops -- rice, wheat and maize -- are grown on lowland fields and 2 crops on irrigated upland fields.

But these indigenous systems are not flawless. Conflicts erupt frequently between water users, chiefly in areas where user rights have not been clearly defined (See box Resolving water conflicts at home). At CMIS, much labour is needed every year to manually clean and repair the canal since the Tinao river carries stones, logs and sediments into the irrigation canals. But the lesson to be learnt here is that native genius can surpass urban engineering skills. Those close to the soil are competent and knowledgeable; it is they who have an insider"s view of their environment and its resources. External intervention is really needed only to strengthen these systems. It would be ill-advised to replace them.

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