Hydrometeorological study of Karanja project in Karnataka State for estimating design storm

Abstract

A detailed hydro meteorological study of the catchments unto the Karanja dam site has been made to estimate the design storm depths of different return periods and the probable maximum rainfall likely to be experienced by the catchments using rainfall data of the period 1891-1984. It has been found that the catchments experienced maximum rainfall of 193,258 and 312mm during 1,2 and 3 days period respectively during the last 94 years of record. Severe rainstorms of September 1908 and July 1965 that occurred in a homogeneous region around the catchments were transposed to estimate probable maximum rain depths (PMP). The PMP for 1,2 and3 days durations were found to be 338, 406 and 424 mm respectively, which are about 1 .4 to 1 .8 times the Corresponding maximum rain depths experienced by the catchments. These design estimates will be useful for the re-assessment of the spillway capacity of the existing dam across the Karanja river at Halhalli.