Abstract:
Climate change poses one of the greatest challenges of the 21st century, necessitating a
comprehensive investigation into its regional hydroclimatic impacts. This thesis examines
future climatic trends over the Potohar region and assesses hydrological responses across its
primary Basins (Haro, Soan, and Kanshi) utilizing high-resolution datasets and the Soil and
Water Assessment Tool (SWAT) model. We evaluate these changes under three Shared
Socioeconomic Pathways (SSPs: 245, 370, and 585) spanning the 21st century. After
meticulously evaluating precipitation and temperature data from 54 General Circulation
Models (GCMs), we identify the top two models best suited for this study: CNRM-ESM2-1
r1i1p1f2 and EC-EARTH3-VEG r3i1p1f1. These models undergo bias correction via Linear
Scaling to provide accurate projections of future climate. Our results reveal a wetter and
warmer climate over Potohar. Temperature shows a consistent increase across all scenarios,
with projections ranging from 0.60°C to 3.38°C for SSP245, 0.47°C to 3.84°C for SSP370, and
0.57°C to 6.26°C for SSP585, intensifying as the century progresses. Precipitation projections,
unlike temperature, exhibit significant temporal and spatial variability. However, most SSPs
indicate increased precipitation during the monsoon (JJAS) and reduction in winter (DJF). The
Potohar region may experience an annual precipitation increase of 3-17% for SSP245, 1-28%
for SSP370, and a range of -5% to 23% for SSP585, till century end. Streamflow projections
across the HARO (-4% to 98%) and SOAN (-10% to 44%) basins generally indicate an annual
increase over future periods, while KANSHI (-24% to 31%) exhibits a mixed trend across the
GCMs. Seasonal analysis further reveals distinct flow patterns across the three basins. Also,
the EC-EARTH predicts a one-month earlier attainment of peak flow across all basins in most
SSPs. Interannual projections of hydroclimatic variables suggest more frequent extreme events.
The changes quantified in this study underscore the urgent need for adaptive water management
and region-specific climate action plans to mitigate climate change impacts on water resources,
agriculture, urban planning, and disaster risk reduction in the Potohar region.
