Impact of Land Use/Land Cover Change on Runoff using SWAT Modelling: A
Case Study in Upper Prek Thnot Watershed in Cambodia
Abstract
Changes in land use/land cover (LULC) may result in water shortages,
flood risk and soil erosion, contributing to the degradation of living
conditions. Recognition of the impacts of LULC changes on water
resources is a crucial aspect of watershed management. Thus, this paper
aims to determine how LULC change affects runoff and other hydrological
components including: groundwater, water yield, procolation and
evaportranspiration in Upper Prek Thnot watershed from 2006 to 2018 by
using SWAT modelling. The result indicates that LULC of Upper Prek Thnot
watershed experienced such significant changes during these 13 years.
Conversion of forest area into agricultural land was the main
modification in the study area, which accounts for 39%. This followed
by an increase of rubber plantation, built-up area, barren land and
water bodies and a decrease of the wood shrub. These changes resulted in
a corresponding increase in annual average surface runoff (36%) and
water yield (2%), and a decrease of groundwater (24%), percolation
(8%) and evapotranspiration (1%). In particular, if the forest area is
converted to agricultural land, especially if the conversion takes place
in large numbers, the hydrological elements will be significantly
affected. Consequently, due to a noticeable alteration of LULC in the
study area, a sound strategic management plan should be applied
considerably to ensure the sustainability of ecosystem services.