Technical and Hydro-geological Surveys

Nobariya, Egypt and Korba, Tunisia

The core of the technical and hydro-geological surveys of IMPROWARE has been to characterise the Nobariya (Egypt) and Korba (Tunisia) sites on their hydro-geological aspects, in order to manage properly the artificial recharge of the aquifer.

The main activities between October and December have focused on developing a Finite Element Model (FEM) in the Nobarya Region, northern part of Egypt. These activities have been carried out with the main goals of:

• describing the behavior of the hydrological elements and over time evolution of the hydro-geological conditions in the area. In fact, as a consequence of the recuperation of the region for agricultural purposes,  it has experienced a significant evolution over time – passing from arid to wetland over the last 30 years;

• defining appropriate benchmark and initial conditions of a local scale groundwater flow and transport model that will be developed in the second phase to investigate various scenarios of aquifer recharge.

Since numerical models represent a powerful tool to predict the evolution of the groundwater flow and groundwater quality due to natural forcing factors (e.g. reduced natural recharge due to climate changes) and anthropogenic activities (groundwater pumping or recharge), IMPROWARE has used a state-of-the-art finite-element groundwater flow/transport simulator called “FLOW3D”. This simulator allows a complete three-dimensional representation of a great number of parameters, like the aquifer system, the full transient, semi-transient and steady-state flow and transport processes and handle heterogeneous materials and solute properties, including conductivities, dispersivities, porosities, distribution coefficients, mass transfer coefficients, and decay constants.

Furthermore, an accurate hydro-geological characterization of the subsurface system has been carried out by integrating in-situ investigation and numerical modeling in order to develop reliable simulation of the effects of i) aquifer recharge (both by infiltration basins and wells) and ii) groundwater pumping. Different kinds of data available has been collected and integrated to build the three-dimensional architecture for the hydrological model of the selected site including:

• the litho-stratigraphy of the basin, with particular emphasis on the geometry of the aquifers;

• the hydrological and geo-mechanical properties of the aquifers and the intervening aquitards or semi-impermeable units (e.g. porosity, hydraulic conductivity, elastic storage, soil compressibility, etc.);

• the digital elevation model of the area and the geometry of the main drainage network;

• the climatic regime (e.g. temperature, wind, precipitation, solar radiation) over the last several years;

• the historical behaviour (measurements and/or estimations) of the groundwater volumes pumped out from the subsurface, with the location of the wells, the intake depths;

• the records of the evolution of the pond surface developed over the years in Nobariya.