Projecting Groundwater Variability in Data-scarce Tropical Savanna
Region of India
Abstract
For regional sustainability, spatio-temporal variability of groundwater
level (GWL) in tropical savanna climatic region with heavily stressed
aquifers needs future projection skills by taking hydrological,
geological, and climatic (HGC) controls into consideration. This study
analyzed the spatio-temporal variability of quarterly GWL and the HGC
controls regulating it during the 1995-2015 period over a data-scarce
tropical savanna region in India. Using data mining techniques, the
study evaluated land use land cover (LULC), geomorphology, lithology,
topography and rainfall as HGC controls for GWL variability. The
analysis revealed that this region has high intra-annual spatial
variability characterized by higher GWL variability in the drier period
of the year than wet period. The temporal analysis of GWL demarcated the
distinct regions with highly significant rising and declining trends
with magnitude ranging from -0.51 to 0.42 m/year. It was discovered that
the LULC could explain the observed GWL variability at the highest
degree compared to the other considered HGC controls. Subsequently,
through principal component analysis (PCA) six representative components
covering more than 90% of the variance in 2002 LULC dataset were used
for training the random forest (RF) learning algorithm to develop four
prediction models corresponding to four temporal quarters. The PCA-RF
based trained prediction models showed adequate accuracy during testing
using the 2005, 2010, and 2015 LULC datasets. The developed models were
further used to make short- and long-term GWL predictions in the study
region. The developed models can contribute to regional-scale
groundwater planning and management in data-scarce tropical regions.