The use [of] GIS and remote sensing in the assessment of Magat Watershed in the Philippines : a thesis presented in partial fulfilment of the requirements for the degree of Master of Environmental Management, Massey University, Turitea campus, Palmerston North, New Zealand
The Philippine watersheds are continually being degraded— thus threatening the supply
of water in the country. The government has recognised the need for effective
monitoring and management to avert the declining condition of these watersheds. This
study explores the applications of remote sensing and Geographical Information
Systems (GIS), in the collection of information and analysis of data, in order to support
the development of effective critical watershed management strategies.
Remote sensing was used to identify and classify the land cover in the study area. Both
supervised and unsupervised methods were employed to establish the most appropriate
technique in watershed land cover classification. GIS technology was utilised for the
analysis of the land cover data and soil erosion modelling. The watershed boundary was
delineated from a digital elevation model, using the hydrological tools in GIS.
The watershed classification revealed a high percentage of grassland and increasing
agricultural land use, in the study area. The soil erosion modelling showed an extremely
high erosion risk in the bare lands and a high erosion risk in the agriculture areas. This
supports the need for effective conservation strategies and a land use plan in the study
area. The use of remote sensing and GIS could assist watershed environmental planners
and managers to achieve this objective.