Catchment Discharge Modelling for Maintaining the Water Resources in the Lesti Sub-Catchment of Upstream Brantas

Regional planning that ignoring the level ability of area will cause the area damage and it will influence the fluctuation of water ability in the catchment. The effort of evaluation and regional planning which are based on the water availibility and the demand will give the benefit illustration in the water resources management. This study intended to analyze the discharge model for regional planning based on the rainfall, evaporation, soil condition, and land use area in the catchment, so the impact of produced discharge of the regional function can be suitable. The water balance method was used for building the discharge model. Location of the study is determined by considering the data availibility on the rainfall and discharge recorder. The methodologies consist of the field survey, the analysis of catchment map and the river network by using the Geographical Information System (GIS). Result of the discharge modelling in the Lesti Sub-catchment showed that the influenced factor was rainfall, evapotranspiration, water holding capacity, and water surplus in the soil. The relation among the fourth factors indicated that the variance inflation factor (VIF) was less than 10. It meaned that there was no multi-co-liniearity among the fourth independent variables. The discharge value was hoped to be able to use as the regional planning of upstream catchment by considering the water balance and catchment maintainance.DOI: http://dx.doi.org/10.5755/j01.erem.74.1.19558