Conformity evaluation of synthetic unit hydrograph (case study at upstream Brantas sub watershed, East Java Province of Indonesia)

Abstract

Abstract This study intends to analyse the suitable hydrograph in upstream Brantas sub watershed. The methodology consists of comparing the result of hydrograph due to the methods of Nakayasu synthetic unit hydrograph (SUH), Limantara synthetic unit hydrograph, and the observed unit hydrograph. In detail, this study intends to know the difference of hydrograph parameters: α and Tg as recommended by Nakayasu and in the study location; to know the influence of main river length which is used in the methods of Nakayasu and Limantara to the time of concentration; to know the hydrograph ordinate deviation between Nakayasu and Limantara due to the observed hydrograph. Result is hoped for recommending the suitable hydrograph in upstream Brantas subwatershed so that it can be used accurately for the further design of water resources structure.