Hydrological Impact of Land Use and Climate Change on The West Coast River Basins of Karnataka
Date
2023
Authors
T.M, Sharannya
Journal Title
Journal ISSN
Volume Title
Publisher
National Institute Of Technology Karnataka Surathkal
Abstract
The Western Ghats of India is an environmental and climate-sensitive region of India.
The Western Ghats are the mountainous forest range of a tropical region that play
significant role in distributing Indian monsoon rains. Three west-flowing rivers of the
Western Ghats representing different levels of anthropogenic influence were chosen for
this study to understand the individual and combined effect of land use land cover
(LULC) and climate change (CC) on the hydrology of river basins that spread over the
northern, middle and southern portion of the west coast Karnataka. The study was
carried out with five objectives which include (i) Assessment of satellite and India
Meteorological Department (IMD) rainfall products for streamflow simulation in the
study area, (ii) To investigate long-term changes in current LULC and model predicted
future LULC scenarios on streamflow, (iii) To evaluate the impact of long-term climate
change on regional hydrology using SWAT and to assess the river basin responses, (iv)
To assess the combined impact of land use land cover change and climate change over
the study area, (v) Scenario analysis of the combined effect of land-use change and
climate change on blue water and green water availability.
Evaluation of satellite precipitation data was performed using the Tropical Rainfall
Measuring Mission (TRMM) and Climate Hazards Group InfraRed Precipitation with
Station data (CHIRPS), employing a semi-distributed hydrological model, i.e., Soil and
Water Assessment Tool (SWAT), for simulating streamflow and validating them
against the flows generated by the India Meteorological Department (IMD) rainfall
dataset. The historical land use (LU) changes were studied for four decades (1988–
2016) using the maximum likelihood algorithm and the long-term LU (2016–2100) was
estimated using the Dyna-CLUE prediction model. Five General Circulation Models
(GCMs) were utilized to assess the effects of climate change (CC) and the SWAT
model was used for hydrological modeling of the three river basins. To characterize
granular effects of LU and CC on regional hydrology, a scenario approach was adopted
and three scenarios depicting near-future (2006–2040), mid-future (2041–2070), and
far future (2071–2100) based on climate were established.
iIt was observed that the IMD rainfall-driven streamflow emerged as the best followed
by the TRMM, CHIRPS-0.05, and CHIRPS-0.25. The impact of climate change was
more predominant than the impact due to land use land cover. However, deforestation
and the conversion of other LULC into an unorganized plantation/ agriculture with
urban expansion contribute to an increase in streamflow. As per the water availability
and vulnerability assessment, the Aghanashini basin was classified under the extremely
vulnerable sector, Gurupura and Varahi basins under the low vulnerable sector for water
scarcity. The thesis is an attempt to study the LULC comprehensively on the impact on
rivers of the Western Ghats of India and is an effective tool in understanding the
hydrological impacts and adopting strategies to counter the impacts of LULC and CC.
Description
Keywords
Climate Change, Dyna CLUE, Land Use, Satellite precipitation data