Abstract:
Land use land cover change (LULC) is a very significant issue in terms of global dynamics
and their responses to hydrological features and the soil and water management of a
watershed because it has a great effect on stream flow. This study aims to evaluate and
predict the land use and land cover change effect on Suha stream flow using the QSWAT
model. The land use land cover data were downloaded from USGS Earth Explorer and were
used to develop land use land cover maps for 1992, 2007, and 2022 by using semi-automatic
supervised classification plugin techniques. A prediction of future land use land cover maps
for 2037 and 2052 was prepared using Cellular-Markov model. The physical-based, semidistributed QSWAT model was used to simulate LULC effects on the hydrological response of
Suha watershed. The performance of this model was evaluated through sensitivity analysis,
calibration, and validation using SWAT-CUP. The coefficient of determination (0.87-0.90)
and Nash-Sutcliff efficiency (0.79-0.86) values were acceptable and showed good agreement
between monthly observed and monthly simulated stream flow for calibration and validation
for the study periods. The results of study indicate that mean seasonal stream flow increased
from 58.8 to 68.9m
3
/s and 56.6 to 64.6m
3
/s for wet season and decreased from 5.4 to 1.98m
3
/s
and 5.2 to 3.93m
3
/s in dry season for both calibration and validation period, respectively. The
mean annual surface runoff increased from 108.62 to 139.8mm, while the mean annual
groundwater flow decreased from 84.2 to 62.23mm throughout the whole period. Due to the
expansion of agriculture, built areas, and bare lands and reduction of forests, shrubs, and
grass lands, increasing surface runoff and stream flow in the wet season and decreasing
stream flow and ground water flow in the dry season within Suha watershed was occurred.
Hence, controlled measures of soil and water conservation practices with biological measures
should be taken to minimize land use land cover change, stream flow, and groundwater flow
change by natural resource managers, planners, policy makers and concerned stakeholders.
Key Words: QSWAT, Cellular-Markov, Suha stream flow, land use land cover change