The response of water balance components to land cover change based on hydrologic modeling and partial least squares regression (PLSR) analysis in the Upper Awash Basin

Abstract

Study region: Upper Awash basin at the headwater of Awash River. Study focus: Comprehensive assessment of land cover (LC) change effect on the water balance components using integrated approaches of hydrologic modeling and partial least squares regression (PLSR) provides better understandings of the impact of recent development activities on water resources. The SWAT model was validated at five subbasins and used to simulate the water balance and hydrologic response to LC changes at multiple temporal and spatial scales. PLSR was used to evaluate the significance of the relative influence of LC classes on the hydrologic components. New hydrological insights for the region: Based on the multitemporal LC change detections, Upper Awash basin is characterized by the decline of natural vegetation due to the swelling rise of cropland and urbanization. The monoplot of PLSR components exhibited that groundwater is highly correlated with the forest areas and lateral flow is strongly correlated with pasture, whereas, surface runoff is significantly attributed to the change in urban and cropland. The Variable Importance for the Projection (VIP) and PLSR weight (w) revealed that the decline of groundwater is mainly due to urban (VIP = 1.34 and w=-0.55), whereas, the change in forest area enhanced groundwater (VIP = 1.04 and w = 0.47). The study provides valuable information on the contribution of particular LC to change in water balance which is vital for improved water resources management. Keywords: Land cover change, Water balance component, Partial least squares regression, SWAT model, Upper Awash basin