Assessing the groundwater flow regime in coastal aquifers is a challenge for numerical modelers. In order to have a complete set of parameters and input data for a valuable numerical simulation we need to compile several hydrogeological studies, reconstruct datasets and proof the accuracy of hydraulic tests. Still some parameter would be missing but the experience and criteria of the groundwater modeler would achieve adequate simulations and predictions required by an adaptive sustainable groundwater resources management.
Hydrogeological conceptualization of the main physical process related to groundwater flow in coastal aquifers is complex with main focus on:
Recharge from river infiltration and irrigation areas
Pumping well exploitation
Discharge and interaction with seawater
Evapotranspiration in zones with water table close to surface
This tutorial shows the whole process of model geometry construction, boundary condition implementation, set up of the observation points and simulation on steady state conditions. There is a discussion on the model water balance and the stage of the simulation results.
The boundary conditions implemented for this model are:
Recharge from irrigation areas.
Simulation of river interaction with the aquifer.
Well abstraction in pumping wells.
General Head Boundary (GHB):
Simulation of the aquifer interaction with the sea.
Simulate the evapotranspiration from groundwater in zones with elevated water table.
The study case developed in this tutorial include the implementation of the observation point package (HOB) from a shapefile with the specification of the screen elevation and the observed head form the shapefile attributes.
You can download the input files for this tutorial here.