Integrated Water Resources Modeling to Estimate the Risk of Groundwater
Depletion in Semi-arid Basins in a Context of Climate Change
Abstract
The increase in world population, added to socioeconomic development and
climate change, have highlighted one of the biggest problems worldwide:
the depletion of water resources. The La Ligua and Petorca river basins,
in central Chile, are an example of this problem, as rainfall has
decreased in recent years, while socio-economic activities, mainly
agriculture have increase. This situation has led to a severe water
stress, and the need for integrated and sustainable river basin
management, aimed at understanding the behavior of basins, aquifers, and
the exchange of flows between them. Therefore, the main objective of
this research is to quantify the impacts of climate change, in terms of
groundwater scarcity, in semi-arid basins using integrated modeling of
water resources. For this purpose, groundwater/surface waters integrated
models of La Ligua and Petorca basins were developed using WEAP and
MODFLOW. Both basins present different hydrological, social, and
geographical characteristics. Different scenarios were evaluated to
quantify groundwater depletion. These scenarios depend on climatic
forcings, such as precipitation and temperature, which were obtained
from the Phase 6 of the Coupled Model Intercomparison Project (CMIP6).
Results forecast that annual precipitation will decrease, whereas
average annual temperature will increase in these semi-arid regions. As
a consequence, the aquifer’s recovery rate will reduce, decreasing the
number of wells that provide drinking water in rural and agricultural
areas. In conclusion, the coupling of hydrological and hydrogeological
models is a tool that allows researchers and stakeholders to make
opportune and appropriate decisions on the management of basins and
aquifers, which is even more important in basins that are expected to be
or are already under severe water stress.