CS(AR)-17/99-2000 : Raingauge network design for Pagaladiya basin

Abstract

Precipitation is the most basic data required for any water resources studies. Estimation of the number and location of the rain gauge stations which will provide sufficient information regarding rainfall falling over the catchment is referred as network design. A rain gauge network is intended to serve the general as well as specific purposes such as water supply, hydro power generation, flood forecasting, irrigation and flood control etc.

In the present study, the network design for the Pagladiya basin has been carried out. Rainfall occur mostly during March to October in the basin. During March and April the rainfall is sporadic, but it is steady and heavy or very heavy during May to October. Annual rainfall in the basin is over 2300 mm. Wide spatial variation of rainfall is observed in this catchment. The rainfall data of ten existing raingauge stations in and around the study area have been analysed using various methods which take into account the location of raingauges and type of basin and its climate, precipitation characteristics from the existing raingauge stations etc. Apart from BIS recommendations, Cv,. method, Key station method, Spatial correlation method and Entropy method have been used. Based on the study, it has been found that additional stations are required in certain parts of the basin while in other parts some redundant stations have been identified. For adequate and economical network design discontinuation of two existing stations and installation of additional 4 stations have been proposed in the catchment with their possible locations.