--- title: "Need and challenges of irrigation in Nepal" subject: "Irrigation and Drainage Engineering" chapter: 1 key: "semester_6/irrigation_and_drainage_engineering:nepal-irrigation-need-challenges" source: https://www.bctengineer.com/q/semester_6/irrigation_and_drainage_engineering/nepal-irrigation-need-challenges site: BCT Engineering --- # Need and challenges of irrigation in Nepal Irrigation and Drainage Engineering · Chapter 1: Introduction - Asked in: 2081 Chaitra, 4+4 marks; 2080 Chaitra, 6 marks; 2078 Baisakh, 3 marks; 2076 Bhadra, 5 marks; 2074 Bhadra, 3 marks; 2073 Bhadra, 4 marks; 2071 Bhadra, 3 marks; 2068 Chaitra (old course), 5 marks; 2064 Kartik (old course), 4 marks (asked 9 times) - Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14 - Page: https://www.bctengineer.com/q/semester_6/irrigation_and_drainage_engineering/nepal-irrigation-need-challenges - Whole chapter: https://www.bctengineer.com/md/semester_6/irrigation_and_drainage_engineering/chapter-1 ## Question Explain the necessity (importance) of irrigation development in Nepal. Discuss the problems and challenges of irrigation development in Nepal. ## Short answer Irrigation is vital in Nepal due to 80% rain in monsoon, agriculture's role in economy, need for higher yields and cropping intensity, and climate uncertainty. Major challenges are steep terrain, flood/sediment damage, poor O&M, weak WUAs, funding constraints, water conflicts, and land fragmentation. ## Answer #### 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. ## Check yourself The answer's key points as multiple-choice questions, with the correct option and why. 1. Why is irrigation especially needed in Nepal for winter and spring crops? A. About 80% of rain falls in June-September, leaving the other months dry B. Rain is spread evenly but is too little overall C. Rivers freeze in winter so crops need canals D. Monsoon rain is too heavy for crops to grow Answer: A. Rainfall is concentrated in the monsoon, so dry-season crops depend on irrigation. (Key point: Uneven rainfall) 2. What benefit of irrigation over rainfed farming does the answer give? A. Same yield but cheaper seed B. 1.5 to 2 times the yield and 2-3 crops a year C. Ten times the yield with a single crop D. Lower yield but less labour Answer: B. Irrigated land gives higher yield and cropping intensity, which helps food security. (Key point: Yield benefit) 3. Why are irrigation canals difficult and costly in Nepal's hills? A. Hills have too little slope for gravity flow B. Soils in hills are too sandy to hold canals C. Steep fragile terrain with landslides, plus floods and sediment damaging headworks and canals D. There are no rivers in the hills Answer: C. Steep landslide-prone slopes and monsoon floods with heavy sediment raise construction and maintenance cost. (Key point: Topography and flood challenge) 4. Which is listed as an institutional problem of irrigation development? A. Too many trained technical staff B. Excess funds from the government C. Perfect coordination among agencies D. Weak WUA capacity and low irrigation service fee collection Answer: D. Weak water user associations, low fee collection and limited staff hamper operation and maintenance. (Key point: Institutional weakness) ## Related in Irrigation and Drainage Engineering - [Status of irrigation development in Nepal](https://www.bctengineer.com/question.md?key=semester_6%2Firrigation_and_drainage_engineering%3Airrigation-status-nepal) — Irrigation and Drainage Engineering, chapter 1, asked 4× - [Irrigation, disadvantages, scope in Nepal](https://www.bctengineer.com/question.md?key=semester_6%2Firrigation_and_drainage_engineering%3Adefine-irrigation-scope-nepal) — Irrigation and Drainage Engineering, chapter 1 - [Fish ladder position and necessity](https://www.bctengineer.com/question.md?key=semester_6%2Firrigation_and_drainage_engineering%3Afish-ladder-necessity) — Irrigation and Drainage Engineering, chapter 5 - [Short note: Problems of sprinklers](https://www.bctengineer.com/question.md?key=semester_6%2Firrigation_and_drainage_engineering%3Asprinkler-problems-note) — Irrigation and Drainage Engineering, chapter 1 ## Related in other subjects - [Challenges and hydropotential of Nepal](https://www.bctengineer.com/question.md?key=semester_7%2Fhydropower_engineering%3Achallenges-hydropotential-nepal) — Hydropower Engineering, chapter 1 - [Goals, need of transparency, challenges](https://www.bctengineer.com/question.md?key=semester_7%2Fdistributed_system%3Agoals-transparency-challenges) — Distributed System, chapter 1 - [Role of groundwater in irrigation development](https://www.bctengineer.com/question.md?key=semester_5%2Fengineering_hydrology%3Agroundwater-irrigation-role) — Engineering Hydrology, chapter 1 - [EIA; environmental problems in Nepal](https://www.bctengineer.com/question.md?key=semester_7%2Fproject_engineering%3Aeia-nepal-problems-improve) — Project Engineering, chapter 2