Evaluating Impact of Land-Use/Land-Cover Change on Surface Runoff using Arc SWAT Model in Sore and Geba Watershed, Ethiopia

Tarekegn Getinet Mekuriaw

doi:10.7176/jees/9-10-02

Abstract

The aim of this study is to assess the impact of LULC change on surface runoff in the watershed of Sore and Geba, the upper Baro-river basin covering an area of approximately 6551 km 2 in Ethiopia. Landsat images were used to analyze the LULC change trends for the periods of three decades (1987-2017). LULC map of the area produced using the maximum likelihood algorithms based supervised image classification. Trends in LULC change showed that farm land has augmented by 16.55% within the periods of between 1987 and 2017with annual expansion by 36.15 km 2 at the expense of other land use types such as open forest, dense forest and wood land. The Soil and Water Assessment Tool (SWAT) model has been used to evaluate the impacts of LULC change on surface runoff. Nine sensitive flow control parameters were identified and used for calibration of the model. In both calibration and validation periods, good performance was obtained. Results show between 1987 and 2017, a 16.5% cultivated land expansion was observed which may explain an increase of about 6.65 m 3 /s (32 mm) in annual surface runoff. In general, during the study period significant influence of LULC change were reflected in changes to the hydrologic system of the region with an important management implication for this region as well as other similar regions in Ethiopia. Keywords : Land use change, Sore and Geba watershed, Surface runoff, SWAT DOI : 10.7176/JEES/9-10-02 Publication date :October 31 st 2019

Highlights

Water is an indispensable for living and non-living environment
Land use and land cover maps Using supervised image classification techniques in Sore and Geba watershed five main land use types have been identified such as cultivated land, dense forest, open forest, woodland and water bodies
The 1987, 2001 and 2017 land use map generated from Landsat-5-TM, Landsat-7-ETM+ and Landsat 8 image classification respectively was shown in Figure 4 blow

Summary

Introduction

Water is an indispensable for living and non-living environment. The quality and the available amount of water in relation to human needs and population growth are still limited. Sustainable land use planning has a close link with water bodies as changes in lan use pattern has an effect on water resource through the relevant process of the hydrological cycle (Guo et al, 2008; Zhang L., 2016; Santosh M. et al, 2018; Birhanu A, 2019). The availability of water in a given area depends on how the precipitation of the area is separated from different elements of the hydrologic cycle such as groundwater recharge, interflow, evaporation, surface runoff. Rapid extension of farmlands towards natural forests and vegetation has deepened the problem of land squalor, through soil degradation by water Rapid extension of farmlands towards natural forests and vegetation has deepened the problem of land squalor, through soil degradation by water (Bewket and Abebe, 2013; Santosh M. et al, 2018; Kondoh A. 2018; Birhanu A, 2019)

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