Land Use Land Cover Change and Its Implication on Surface Runoff: A Case Study of Baro River Basin in South Western Ethiopia

The Baro river basin in the south western Ethiopia is potentially rich in land and fresh water resources. But, the resource of this basin is highly under change starting since 1986. The main goal of this study was to analyse land use land cover change and its impact on surface runoff processes using Geographical information systems, remote sensing techniques and simple empirical formula runoff coefficient. The result revealed that a significant spatial temporal increment and decrement of different land use land cover types in area. The major causes of these land use land cover changes were massive resettlement/ population growth, over utilization of resources and expansion of commercial farming system. This dynamical change of land use land cover has implied effect on environment by degrading in the form of surface water variability. As a result, temporally analyzed potential surface runoff has increased from 37 to 49 percent in 1984 and 2001 respectively. Land use land cover change has not only disrupted ecological balance of the watershed but also increased surface runoff. Keywords: LULC, Surface runoff, GIS, Baro basi

Hydrologic responses of watershed assessment to land cover and climate change using soil and water assessment tool model

Predicting the impact of land cover and climate change on hydrologic responses using modeling tools are essential in understanding the movement and pattern of hydrologic processes within the watershed. The paper provided potential implications of land conversions and climate change scenarios on the hydrologic processes of Muleta watershed using soil and water assessment tool model. Model inputs used include interferometric synthetic aperture radar-digital elevation model, 2016 land cover map, soil map, meteorological and hydrologic data. The model was calibrated using appropriate statistical parameters (R2=0.80, NS=0.80 and RSR=0.45). Model validation using observed streamflow with the same statistical parameters (R2 = 0.79, NS = 0.67 and RSR = 0.57) showed that the result was statistically acceptable. The model provided potential implications of land conversions and climate change adversely affecting hydrologic processes of critical watersheds. Climate change projections with a 13% decrease in rainfall directly influenced the decrease in hydrologic processes. Meanwhile, urbanization had influenced the increase in surface runoff, evapotranspiration, and baseflow. The increase of forest vegetation resulted in a minimal decrease in baseflow and surface runoff. The watershed hydrologic processes were influenced by changes in land cover and climate. Results of this study are useful by the localities and policy makers in coming up with a more informed decision relative to the issues and concern on hydrological responses in the uplands

ANALYZING THE IMPACTS OF LAND COVER CHANGE TO THE HYDROLOGIC AND HYDRAULIC BEHAVIOURS OF THE PHILIPPINES' THIRD LARGEST RIVER BASIN

Changes in land cover can have negative impacts on the hydrological and hydraulic processes in river basins and watersheds such as increase in surface runoff and peak flows, and greater incidence, risk and vulnerability of flooding. In this study, the impacts of land-cover changes to the hydrologic and hydraulic behaviours of the Agusan River Basin (ARB), the third largest river basin in the Philippines, was analysed using an integrated approach involving Remote Sensing (RS), Geographic Information System (GIS), and hydrologic and hydraulic models. Different land-cover classes in the ARB for the years 1995 and 2017 were mapped using Landsat 5 TM and Landsat 8 OLI images. Using a post-classification change detection approach, changes in land-cover were then determined. The impacts of these changes in land-cover to the to the basin discharge were then estimated using a calibrated hydrologic model based on the Hydrologic Engineering Center - Hydrologic Modeling System (HEC-HMS) under different extreme rainfall conditions. The impact of the changes in land-cover to flood depth and extent was also determined using a hydraulic model based on the HEC-RAS (River Analysis System). Land cover classification results revealed that the ARB is 67.7% forest in 1995 but have decreased to 62.8% in 2017. Agricultural areas in the basin were also found to have increased from 12.2% to 15.5% in the same period. Other notable land cover changes detected include the increase in built-up lands and range lands, and decrease in barren lands. HEC HMS and HEC RAS model simulation results showed that there was an increase in discharge, flood depth, and flood extents between 1995 and 2017, implying that that the detected changes in land cover have negative impacts to hydrologic and hydraulic behaviours of the ARB

Integrated Landsat Image Analysis and Hydrologic Modeling to Detect Impacts of 25-Year Land-Cover Change on Surface Runoff in a Philippine Watershed

Abstract: Landsat MSS and ETM+ images were analyzed to detect 25-year land-cover change (1976–2001) in the critical Taguibo Watershed in Mindanao Island, Southern Philippines. This watershed has experienced historical modifications of its land-cover due to the presence of logging industries in the 1950s, and continuous deforestation due to illegal logging and slash-and-burn agriculture in the present time. To estimate the impacts of land-cover change on watershed runoff, land-cover information derived from the Landsat images was utilized to parameterize a GIS-based hydrologic model. The model was then calibrated with field-measured discharge data and used to simulate the responses of the watershed in its year 2001 and year 1976 land-cover conditions. The availability of land-cover information on the most recent state of the watershed from the Landsat ETM+ image made it possible to locate areas for rehabilitation such as barren and logged-over areas. We then created a “rehabilitated ” land-cover condition map of the watershed (re-forestation of logged-over areas and agro-forestation of barren areas) and used it to parameterize the model and predict the runoff responses of the watershed. Model results showed that changes in land-cover from 1976 to 2001 were directly related to th

Análisis multitemporal del cambio de cobertura vegetal y su influencia en la generación de caudales pico de la cuenca del Río Sardinata, del departamento de Norte de Santander - Colombia

Trabajo de InvestigaciónEn el presente estudio se verificó por medio de un análisis multitemporal los cambios presentados en la cobertura vegetal desde el año 2000 hasta el 2012 en la cuenca hidrográfica de Sardinata, posteriormente se realizó el procesamiento y modelación de datos hidrológicos determinando la influencia que ha tenido la variación de las coberturas en la generación de caudales pico de la misma. A partir de lo anterior, se identificó que si bien la escorrentía ha presentado un aumento en la cuenca la variación de las coberturas no es tan significativa para generar caudales pico.INTRODUCCIÓN 1. GENERALIDADES DEL TRABAJO DE GRADO 2. MARCOS DE REFERENCIA 3. MATERIALES Y METODOLOGÍA 4. ANÁLISIS DE RESULTADOS 5. CONCLUSIONES 6. RECOMENDACIONES BIBLIOGRAFÍAEspecializaciónEspecialista en Recursos Hídrico