Cost Effectiveness of Rainwater Harvesting for Groundwater Recharge in Micro-Watersheds of Kolar District of India: The Case Study of Thotli Micro-Watershed

This study has estimated the supply augmentation of groundwater recharge due to creation of water harvesting structures and has assessed the cost-effectiveness of rainwater harvesting for groundwater recharge on watershed basis in one of the sub-watersheds of the Kolar district, Peninsular India — a typically hard-rock area. The study is based on the primary data for the year 2008-09 collected from a sample of 90 farmers having irrigation bore-wells in the selected watershed named Thotli. The study has indicated that the annual draft of irrigation water exceeds the annual recharge, causing a negative balance. On an average, the returns per rupee investment have been found to be ` 1.80 on farm pond, ` 1.78 on recharge pit and ` 1.39 on field bund. The cost incurred to impound a metre cube of water has been found as ` 3.01 in the case of field bund, where estimated recharge benefit is 5.6 m3, ` 1.67 /m3 in the case of recharge pit (with an estimated recharge benefit of 720 m3), and ` 1.33 /m3 in the case of farm pond (recharge benefit of 1350 m3). The discounted cost-benefit analysis of the investment on water harvesting structures has indicated that the investment on water harvesting structures is cost-effective and financially-viable.Rainwater harvesting, Economic feasibility, Groundwater recharge, Watershed, Agricultural and Food Policy, Q15, Q25,

Tillage and crop rotation effects on subsurface drainage response to rainfall

A field study was conducted to determine if tillage and crop rotation affected subsurface drainage response to rainfall. An instrumentation system collected subsurface drain flow data from thirty-six, 0.4 ha plots during the 1993, 1994 and 1995 growing seasons. Response time, time-to-peak drain flow rate, drainage volume, peak drain flow rate and percent preferential flow were compared between two tillage systems (no-till and chisel plow) and two crop rotations (continuous corn and corn-soybean) for 23 drainage events over the three-year study. The influence of preferential flow was estimated for each drainage event using a hydrograph separation procedure based on subsurface drain flow rate changes