Environmental Biotechnology Division, National Environmental Engineering Research Institute, Nehru Marg, Nagpur, 440 020, India.
Environ Monit Assess. 2012 Apr;184(4):2575-91. doi: 10.1007/s10661-006-9575-0. Epub 2007 Feb 8.
Feasibility of an irrigation project is evaluated by two criteria viz., reservoir capacity to irrigate its command area and economic returns by incremental crop production versus capital investment for dam construction. The annual water requirement of different crops in the command area is estimated and compared with the availability of water from the dam for irrigation purpose. The annual crop water requirement is estimated as the sum of evapotranspiration for crops and transmission and other losses. Evapotranspiration is estimated by modified Penman formula. Economics of crop production is analyzed by first estimating the monetary value of existing crop production under current rain fed conditions and then estimating the incremental production of irrigated command area for the proposed crop pattern. The proposed cropping pattern is prepared so as to maximize the benefit of crop production and fodder requirement while maintaining a better crop rotation to improve and maintain physical, chemical, and biological conditions of the soil. The dam is to be used for irrigation and water supply only. Command area served by this reservoir will be 76,500 ha. The existing annual agricultural return is Rs. 2995.56 lakhs and with the proposed irrigation scheme, it is estimated as Rs. 1,77,91.90 lakhs. The incremental annual return would be Rs. 1,47,96.35 lakhs i.e., 642.68% increase in annual return.
灌溉工程的可行性通过两个标准进行评估，即水库的储水量以灌溉其指挥区以及通过增加作物生产与大坝建设的资本投资来获得经济回报。指挥区不同作物的年需水量进行估计，并与大坝用于灌溉的可用水量进行比较。年作物需水量估计为作物蒸散量与输水和其他损失之和。蒸散量通过修正的彭曼公式进行估计。通过首先估计现有作物在当前雨养条件下的货币价值，然后估计拟议作物模式下灌溉指挥区的增量产量，来分析作物生产的经济性。拟议的种植模式旨在在保持更好的轮作以改善和维持土壤的物理、化学和生物条件的同时，最大化作物生产和饲料需求的效益。大坝仅用于灌溉和供水。该水库将为 76500 公顷的指挥区提供服务。现有农业年收入为 2995.56 千万卢比，而采用拟议的灌溉计划后，预计为 17791.90 千万卢比。增量年收入将为 14796.35 千万卢比，即年回报率增加 642.68%。
