Operational satellite-based watershed monitoring systems (SAWMOS) for large humid tropical catchment environment

Operational monitoring the productivity of forested catchment areas is a pivotal task as it provides the water supply for the reservoir and the streamflow. The limitation of conventional method to perform those tasks especially in spatial basis environment and large, remote forested areas made the use of satellite-based techniques could be a useful solution. This study introduces the satellite-based watershed monitoring systems (SAWMOS). SAWMOS is specifically developed to assess the water yield productivity of a watershed using two key hydrological variables; (i) rainfall and (ii) evapotranspiration. The Hulu Perak catchment, at the humid tropical climate region of Peninsular Malaysia which situated at the Southeast Asia is selected as the experimental site. Tropical Rainfall Measuring Misssion (TRMM) and MODIS are used as primary satellite data to estimate both rainfall and ET respectively. The satellite-based water yield estimation is comparable with the actual river flow. The Nash-Sutcliffe Model Efficiency Index indicates acceptable performance of the systems. The forest water yield maps derived from 2003 to 2007 is proved to be reliable to be used for operational spatial-based water yield monitoring at both monthly and annual basis.