Need and challenges of irrigation in Nepal

Necessity of irrigation in Nepal

1. Uneven rainfall: about 80% of annual rain falls in June-September; the remaining months are dry, so winter and spring crops need irrigation.
2. Agriculture-based economy: agriculture supports about 60% of the population and contributes about a quarter of GDP; food security depends on higher yield.
3. Higher yield and cropping intensity: irrigated land gives 1.5 to 2 times the yield of rainfed land and allows 2-3 crops a year.
4. Rising population: limited cultivable land (about 2.6 million ha) must feed more people, so productivity must rise.
5. Use of improved inputs: HYV seeds and fertilizer give full benefit only with assured water.
6. Rural development: employment, income, reduced out-migration; also hydropower/multipurpose benefits and groundwater recharge.
7. Uncertain monsoon and climate change: irrigation protects against delay, breaks and droughts.

Problems and challenges

• Difficult topography: steep, fragile hills; canals pass through landslide-prone areas; high construction and maintenance cost.
• Flood and sediment: monsoon floods damage headworks and canals; heavy sediment silts canals; river bed shifts.
• Low reliability and efficiency: poor O&M, seepage and leakage; many systems get water only in the monsoon (year-round irrigation is far less than the irrigated area).
• Weak institutions: poor water user association (WUA) capacity, low service fee collection, limited technical staff, weak coordination among agencies.
• Funding: large capital needs; delays and cost overrun; dependence on donors.
• Water conflicts and competition among irrigation, drinking water, hydropower and industry; weak water rights.
• Groundwater in the Terai is under-used or overused locally; energy for pumping is costly.
• Climate change causes glacier retreat, dry spells and extreme rain.
• Land fragmentation and small holdings make on-farm distribution difficult.
• Environmental and social issues: land acquisition, resettlement, waterlogging and salinity.

Remedies include rehabilitation, conjunctive use of surface and ground water, micro-irrigation in hills, strong WUAs and joint management.