Hydrologic analysis for river Diversion scheme of Kanupur Dam Project, odisha – a case study

Stream flow diversion is a vital activity during construction of a river valley project that may affect the scheduling of construction activities. Nevertheless, diversion problem of different magnitude exist at all such projects and the schemes are always site-specific. The problem of execution, cost incurred and the time taken for works vary with size of the project and flood potential of the stream. Hence, the diversion schemes of such projects are generally planned prior to the commencement of the construction activities. A case study of Kanupur Dam Project in Odisha state is studied, where construction activity of the earthen dam started on both flanks of the dam much earlier to finalization of diversion scheme. Hydrologic study of a typical river diversion scheme proposed for construction of the earth dam in the river gap portion is presented in this paper. Detailed hydrologic analysis of the river diversion proposal is carried out using method of moment (MOM) and L-moment method using the annual maximum series (AMS) of a downstream gauging station. The derived design discharges Q20 and Q100 adopted for the diversion proposals are derived from Pearson III and Log normal distribution based on D-index analysis under MOM and L-moment method respectively. The study reveals that the proposed scheme would enable for diversion of maximum flood discharge of 2588.757 m³/sec at HFL 417 m over the existing incomplete spillway blocks against maximum observed flood of 2381.24 m³/sec.