Abstract:
Land Use/Land Cover (LULC) change is one of the dominant driving factor that directly
influences on water balance components by transforming the hydrological responses therefore
better understanding of its effects is imperative for sustainable water resources planning and
development notably in developing world like Pakistan where agriculture is a major livelihood.
The study aims to assess the enduring changes in LULC and to quantify their plausible impacts
on hydrological regime of the Potohar plateau. The maximum likelihood classification (MLC)
algorithm for classifying high resolution satellite imageries (1990, 2000, 2010 and 2020);
Cellular-Automata Markov chain model (CA-MCM) for the projection of 2030, 2040 and 2050
LULC maps and the Soil and Water Assessment Tool (SWAT) in conjunction with SWATCUP for hydrological modelling were employed in this research. Hydro-metrological data of
10 × 10 km spatial resolution was taken as the climate input. The LULC analysis revealed that
there was a continual proliferation of agricultural and built-up lands at an expense of forest and
barren land during the 1990–2020 periods, which are anticipated to continue in the 2030, 2040
and 2050 periods. Multi-basin calibrations and validations were performed and the
performance of streamflow simulation was evaluated using four statistical coefficients (R2,
NSE, KGE and PBIAS). The results evince that the model performed well and demonstrating
robustness of model to reproduce flow regime. The LULC changes had decreased mean annual
surface runoff, stream flow and water yield. Conversely, the changes had increased percolation,
sub-surface flow and evapotranspiration. Unregulated infrastructural development has been the
escalating cause of the increased in surface flow and water yield. While increased agricultural
activity was the main driver of water consumption within plateau which added to the increased
evapotranspiration. More significant variation of the hydrological components were perceived
at sub-watershed level, owing to the uneven spatial distribution of LULC than at plateau level.
The outcome of this study will provide pragmatic details to legislative bodies to develop land
and water management ameliorative strategies to harness hydrological changes sustainably.
