Groundwater dynamics in the Indus revealed by integrated flow modeling
and satellite data
Abstract
In the Indus River Basin, groundwater plays a key role in mitigating the
water storage fluctuations due to climate variation and meeting the
rapidly increasing water demand in agriculture dominated basins. A
comprehensive understanding of groundwater dynamics is essential for a
transition to more efficient and sustainable water resources management.
To gain detailed insight response of water flows and storage in the
Indus aquifers to agricultural activities, we build a high resolution 3D
regional groundwater flow model for the entire basin. However, in
practice, regional flow models, as they are most widely used, suffer
from calibration challenges. To address the sparsity of in-situ
groundwater data in the region and to acquire a realistic reproduction
of flow dynamics, we calibrate the model using both in-situ and
satellite-based estimates of ground states. We test the advantage of
such a multi-objective approach by comparing its results with a
single-objective approach in which we constraint the model parameter
only against in-situ data. We examine and discuss the model results for
flow and storage conditions, which reveal: 1) depth to water table has
decreased (1998-2007) almost exclusively in urban areas (1 m), and 2)
groundwater storage depletion averaged ~5cm in
equivalent water thickness basin-wide over 20 years of simulations.
Groundwater storage depletion results primarily from intensive
groundwater withdrawal to meet extensive irrigation demands. Optimizing
crop patterns and associated groundwater extraction in space and time
could improve groundwater conditions.