Variation in rainfall trend at upstream - a threat towards filling schedule of Hirakud Reservoir, India

This study is focusing on the possibility of trend in monthly rainfall of upstream districts of the Hirakud reservoir of Mahanadi basin of Odisha applying Mann-Kendall test. Out of the other monsoon months, almost 19 districts show falling rainfall trend in September at 5% significance level. However, the inflow to reservoir shown declining trend during month of August and no trend in rest monsoon months. As the month of September is sensitive towards filling of reservoir as well as for flood control, the falling trends of rainfall will definitely put an alarm for the planner. The effect of climate change as well as changes in land use and storing/releases of upstream reservoir are suspected for the irregularities found in the pattern. The integrated basin management is also the call of the time for smooth operations of all the reservoirs.