Water resource assessment in Munijhara watershed of Orissa

A study was carried out to assess surface and groundwater resource potential, groundwater development status, water resources availability and demand in Munjihara waterhed of Orissa (India). The annual potential of 1719.55 ha-m includes both surface flow and runoff whereas groundwater potential was estimated to be 940.56 ha-m for the watershed. The annual water requirement was 1656.43 ha-m, which include crop water requirement of 1633.84 ha-m and domestic water demand of22.63 ha-m during the period of 2006–2007. It was estimated that, out of approximately 884 ha-m of utilizable ground water resource in the watershed, about 700 ha-m is being withdrawn annually and there is a scope for exploiting a balance amount of 184 ha-m. Among the dominant crops, paddy accounted for 88% of crop evapotranspiration demand (ET₀) followed by vegetable crops with 6.28% of crop ET₀ during the kharif season. In rabi season total crop evaporative demand was 1117 ha-m and pulse crop accounted for 96% followed by vegetables (2.7%) and oil seed (0.41%). Potential and demand scenario of the study area indicated that there was no water scarcity till 2006–2007 and it may continue till 2011–12 provided demand is fulfilled through groundwater during non-monsoon season. But the study also showed that 27% villages in the watershed were under grey zone where groundwater development is around 65–85% of the utilizable resources and few villages have already been categorized as over-exploited stage. The above findings point towards the fact that, there is need of scientific and rational conservation and utilization of surplus available water which is possible through interventions like design of suitable groundwater recharge structures that would commensurate the rate of draft and can bridge the gap between water availability and requirement.