The morphometric analyses of a catchment area play an important role to sustain the water resources supply. It is important to determine the catchment area and to sustain it to the community. The morphometric analysis was conducted by using the Geographical Information System (GIS) techniques to identify the catchment area and calculated the data of all the morphometric parameters to be analyse. The parameters are discussed about the linear, aerial and relief aspect. For general geology, the updated geological map with a scale 1:25000 has been done. Geological structure found is quartz vein, fracture and joint. The lithology age is from Triassic to Quaternary, composed of pink granite, andesite and interbedded sandstone, mudstone and siltstone. Rek river catchment area is characterised by dendritic to sub-dendritic drainage pattern due to the type of landform which is low elevation of hills. The catchment was determined by using ArcGlS and it has 151126 km2 of area with 998 stream segment and the perimeter of catchment is 71.53 km. The analyses show that the total stream segment and its length is maximum in the first stream order and decreases when the stream order decrease. The stream order found is from 1st order to 6th order means that the water outlet is at 6th order that flow to the Sg. Galas. From all the parameter analysis, the study reveals that the catchment area can be determined by using ArcGIS and morphometric analysis is useful to the future development planning and human activities to be more sustainable in water supply resources.