Climate Resilient Irrigation Scheme (sluice gate of the irrigation system) (Kuenzang Nima)
The climate-resilient irrigation scheme in Khomshar Chiwog under Bardho Gewog (Block), Zhemgang Dzongkhag (District), was funded by the Green Climate Fund (GCF), UNDP-Bhutan. The 3.9 km irrigation system was designed with a high-density polyethylene (HDPE) pipe system benefiting 150 households with a command area of 955 acres (approx. 386 ha). The total irrigation cost incurred was Nu. 18,055,180 (approx. USD 225,700) and was completed in 11 months (7 December 2020 - 7 November 2021). The irrigation scheme was officially handed over to the community on 27 August 2021, upon the formation of a water-user group (WUG).
The smart irrigation system consists of key components, viz. intake, sluice gate, silt-cum-inlet tank, flush-out valves, air release valve, water distribution points, and tail point. The intake collects and diverts the water from the source to the sluice gate. The land users were taught to maintain the intake by regularly clearing it from bushes and removing debris. The sluice gate controls the flow of the water into the tank based on the water requirement. The silt-cum-inlet tank holds the water to settle out sediments and debris before clean water flows through the pipe at a constant rate. Flush out valves clear the sediment and debris from the tank. The air release valve vents out the air trapped in the pipe and water distribution points. Water distribution points deliver water to the users, as required, up to the tail point where water is discharged.
The irrigation scheme fulfils the need for a continuous water supply for both drinking and irrigation purposes. To ensure sustainability, a WUG headed by a chairman, a secretary, and a treasurer was instituted. The WUG ensures operations, maintenance, and harmonious distribution of water. The group is also responsible for the safety of the irrigation system.
The main reason for considering such irrigation scheme as being “climate resilient” is that unlike open earthen channels, this type of irrigation scheme results in zero loss of water through evaporation and leakage, as it is a closed channel. Furthermore, being closed, it is not prone to blockages caused by landslides triggered by rainfall. There is also complete end-to-end management, i.e., management at source including the watershed, and management at tail-end.
The irrigation scheme was constructed by a private company through a contract award: community members were not involved. The irrigation scheme was also accompanied by a land development programme (bench terracing) by a separate contractor, with the prospect of transitioning to irrigated paddy cultivation in the future after adequate soil stabilization. More than 90 acres (36 ha) of fallow lands were revived. This blended approach was applied to ensure the food self-security/sufficiency of the beneficiaries.
Though at a very initial stage, the construction and operation of the irrigation scheme have brought happiness to the beneficiaries. They expressed their hope and expectation of improved crop production, stable and reliable water availability, and major fallow land reversion.
Location: Khomshar Chiwog, Bardho Gewog, Zhemgang Dzongkhag, Bhutan
No. of Technology sites analysed: single site
Spread of the Technology: applied at specific points/ concentrated on a small area
In a permanently protected area?: Nee
Date of implementation: 2021
Type of introduction
Quantity before SLM: 250-300 Drey from one acre paddy land
Quantity after SLM: 600-700 Drey from one acre
The old conventional irrigation channel used to suffer multiple breakdowns quite often. Due to this most of the paddy fields were left fallow (30%) because of insufficient irrigation water. Currently, all the wetlands (100%) are brought under cultivation. Hence, the production has been enhanced.
Note: Drey is a traditional grain measuring container. One Drey is about 1.5 kg.
The paddy harvest appears to be of better quality when there is enough irrigation. Otherwise, the growths are hampered, resulting in higher vegetative growths only.
The higher hay production (by-product) has been beneficial for farmers to feed livestock.
Safe and readily available water to feed the livestock, facilitated by the irrigation scheme has enhanced animal production. Earlier, the farmers used to depend on the far-flung streams/ponds.
Better access to irrigation water has motivated farmers to adopt land development. Hence, about 90 acres of fallow lands in the community have been revived through new terrace constructions.
The irrigation water is being used for drinking purposes too. The drinking water quantity has been enhanced. Earlier, the drinking water source was not enough to meet the requirements due to higher households, especially in winter.
The drinking water tapped from this irrigation is clean and hygienic, unlike before.
Due to new terrace construction, the demand for irrigation water has increased.
One acre of paddy cultivation used to take 4-5 days. Now, one acre takes 1 day. Mechanization is enhanced.
Currently, the impact is at the initial stage (1 year). The income could quantified in the later years.
Irrigation and land development interventions have beautified the community (aesthetic). The external visitors are astonished.
Community dispute over water demand and mid night water guarding during paddy cultivation due to water scarcity used to be rampant before.
The conventional irrigation channel used to result in water seepage and accumulation of groundwater, leading to flooding of underneath fields. Now, this pipe irrigation has been solved and flooding is not evident.
Due to improper irrigation source management before, the water outflow was used to wash away a huge portion of lands and roads below. Due to enhanced source protection, this issue is solved.
