17. Covariation Between LULC Change and Hydrological Balance in River Basin Scale

Land use and land cover (LULC) change has one of the key modes of human modifications and has raised several queries related to its impact on hydrology and climate. Since the LULC plays a vital role in partitioning energy and water fluxes at the land surface into different components, the changes in LULC can impact the water and energy cycles to a significant level. However, at a basin scale, the severity of such consequences depends on the scale, type, and heterogeneity of LULC changes. An assessment of the impacts of LULC change on hydrology in three major river basins—Brahmaputra, Ganga, and Mahanadi of India is performed in this study using the variable infiltration capacity (VIC) model, a physically-based distributed hydrological model. The assessment reveals an important compensating effect in the hydrologic changes resulted from LULC transformations. The negative consequences (e.g., increased surface runoff due to urbanization) at one place are compensated by opposite positive changes (e.g., decreased surface runoff due to forest plantation) at other places at the basin scale. Such compensation leads to insignificant hydrologic changes at the basin scale; however, the consequences are significant at the local and sub-basin scales.