Low-cost ponds to hold water for dry spells

The HKH region has been facing increasing seasonal water shortages. Changes in rainfall patterns, mainly due to climate change, have caused excess rainfall during monsoons and frequent dry spells for the rest of the year.

The problem

Nepal’s Kavre district has been hit hard by climate change and changing rainfall patterns. Over two-thirds of the district’s population depend on agriculture and rely on rainfall for irrigation. We carried out a vulnerability assessment study in three Village Development Committees (VDCs) of Kavre, which revealed that drought and water stress are major challenges faced by farming communities in the district.

To address this issue, the mid-hill farmers of Kavre need simple and affordable practices for efficient water management.

Solution and implementation

Water storage ponds

Cheap and easy-to-build plastic-lined ponds can help farmers save rainwater so that it can be used for irrigation during the dry months.

In partnership with the Centre for Environment and Agricultural Policy Research, Extension, and Development (CEAPRED), we encouraged farmers to dig small ponds close to their house lined with plastic sheeting, allowing them to store household wastewater and rainwater. The plastic lining prevents the water from seeping into the ground. To avoid water losses due to evaporation, farmers were encouraged to locate the ponds under the shade of trees. The collected water can then be used to irrigate home or kitchen gardens during the dry season and during times of drought. In areas with clayey soil, the ponds were not required to be lined with plastic since the clay would retain water naturally.

Most farmers constructed a plastic pond (7 ft. x 4 ft. x 75 cm depth) with a capacity of 2,000 litres. Large community-managed plastic ponds (18 ft. x 24 ft. x 1 m depth) with a capacity of 16,000 litres were also constructed. Large plastic ponds collected wastewater from community drinking water taps, small streams and other water sources. The low-cost water storage pond and community ponds were first piloted in three VDCs of Kavre. The ponds were later implemented in four additional sites in Panchkhal Municipality in Kavre.

“My crops would dry up and wilt in previous years. Thankfully, self-sufficient practices such as plastic ponds have helped us reduce losses in the face of unexpected weather and climate change,”
– Bimala Bajgain of Kalchebesi village

The water-storage plastic ponds are affordable for farmers as they require no further investment other than the purchase of plastic sheets and can be built easily. Because of its simplicity and affordability, more farmers are willing to adopt this method and are likely to share their learning and knowledge with other farmers.

Results

Japan’s Kochi Technology University (KTU) conducted a survey of over 1,000 farmers in Nepal’s western mid-hill agro-ecological zone. It revealed that vegetable production and income could increase more than 30 per cent by simply deploying water-conservation techniques such as water storage ponds.

With these plastic-lined ponds and other simple water management practices, such as drip irrigation, farmers have been able to use and manage available water more efficiently.

Similar water-smart technologies that use a combination of science and local knowledge with low investment and minimal external technical support have also been promoted in eastern Nepal. The Government of Nepal has further ensured the upscaling of these low-cost water-smart technologies as resilient mountain solutions across 14 other districts in Nepal. Along with our partner organizations, we also plan to introduce this technology to other regional member countries of the Hindu Kush Himalaya.