ASSESSMENT AND IMPROVEMENT OF IRRIGATION EFFICIENCY OF SATIGUDA MEDIUM IRRIGATION PROJECT OF ODISHA IN CHANGING CLIMATE

Abstract

In irrigation improvement process medium irrigation systems have received more significance than major irrigation systems due to numerous advantages such as small capital investments, less development period, better flow control and very specifically more farmers' friendly etc. At the global scale, water demand is increasing day to day due to rapid growth of population and at the same time due to climate change irrigation water demand is goes on changing substantially. In such circumstances, many water systems in Odisha are projected to be less reliable and more vulnerable in meeting users' demands, aggravating existing competition of water resources. The present research work aspires to evaluate the irrigation pattern as well as • the reservoir performance of such type of system where the reservoir is being unable to flulfihl the demand in the changing scenario. In this current study, performance of Satiguda Medium - Irrigation project is analyzed under climate change conditions which is being located in the southern part of Odisha. The thesis is focused mainly on the problems which have been identified with the changing climate as the Satiguda Dam and its irrigation system has been in operation science 1980. Continuous seepage is being found at several locations at the body of the dam and in the vicinity of the junction between earthwork and masonry work. In recent years there is problem to provide irrigation to tail-end ayacut during dry spells in Kharif season and also it is becoming very difficult to provide assured irrigation in Rabi season. Restoration of canals and resuming of water supply within a short time period is becoming very difficult. Piping and breaches occur in heavy filling reaches during continuous water supply. It was observed from the study that during last several years there is about 35% ayacut gap between the designed irrigation capacity and achieved irrigation capacity in Kharif season. The condition is even worst in Rabi season as Satiguda project is unable to provide assured irrigation in most of the Rabi season in the recent past. Hence to improve the irrigation scenario and to provide assured irrigation in both Rabi and Kharif season with high irrigation efficiency so as to minimize the gap between the potential created and utilized for the Satiguda medium irrigation project, our study is basically based on three types of approach. They are as follows: In first type of approach water from surplus catchment has been assumed to be diverted to Satiguda to fulfill the demand. From the spillover statement, it was observed that the Satiguda reservoir is unable to service the command area due to inadequate inflow coming over to the reservoir in requisite quantity and in opportune time. In order to overcome such problem and to enhance the irrigation reliability with assured irrigation, water from surplus catchment of Dharadhurgarh and Dharmagarh nallahs link can be effectively use to fulfill the demand. Using the rainfall, inflow data for common period from 1994-2008 the rainfall-runoff modeling was developed and by calculating 75% yield and enhanced crop-water requirement. Finally we concluded with the result that by utilizing the water from that balance reservoir we can enhance the Rabi coverage area to 1.8 times with fulfilling the ayacut gap in Kharif season. . In second type of approach our aim is to change the water delivery pattern by modifying the canal delivery scheduling where we deviate from conventional schedule which was planned as per reservoir operation policy at initial stage. . In third and final way of approach our principal idea is to assess and improve the institutional performance in the form of Pani Panchayat so that water use efficiency can be increased with the available quantity of water by proper coordination and planning between the member farmers. Although each and every way of approach is having their own advantage as well as limitations but individual contribution of all is quite significant in the changing climate scenario for the better development of the project like Satiguda.