Ongoing monitoring and recommendations to combat the salt-water wedge at Oum Errabia
Customer needs
Customer issues
As in Agadir, the climate in the Oum Er Rbia region is semi-arid, and rainfall is very low. Groundwater recharge is therefore often insufficient. However, the need for water for local agriculture and consumption is leading to overexploitation of the water tables, with the intrusion of saline water along the coastline.
At the end of 2023, we were commissioned by the Oum Errabia water basin agency to monitor this phenomenon of saline intrusion and understand the parameters that influence its evolution.
Assets :
4 piezometers
4 SMD devices
The Imageau solution
Setting up the SMD Intrusion monitoring system
To fully understand the factors influencing the progress of saline intrusion into the water tables, it is necessary to collect data over a fairly long period, at least 1 year in order to cover a hydrological cycle. This will enable us to obtain a reliable representation of the different periods of the year in order to observe episodes of drought, humidity and the different conditions of the water table.
To do this, we will be installing our patented SMD Intrusion monitoring tool at 4 different locations to study the dynamics of the salt wedge and the parameters that encourage its advance:
- Are there local farms? Are they pumping too much?
- Is it a natural phenomenon caused by insufficient groundwater recharge due to low rainfall?
The SMD Intrusions system will collect data continuously and in real time to confirm or refute these hypotheses. With this solid basis, we will then be able to make recommendations aimed at slowing down this phenomenon of saline intrusion.
Tailor-made adaptation of the SMD
Piezometers are built to house our probes. One of the advantages of SMD is that it can be adapted to the specific characteristics of each situation.
When the boreholes were drilled, we took salinity measurements at a given point in time in order to determine the depth of the salt wedge. At the 4 sites, the salt wedge appears in completely different places.
Thanks to the data collected, we are able to build a monitoring system tailored to each of the boreholes. Some of the equipment will be shipped in January 2024, and the rest in February 2024, for installation and commissioning the following month.
In this way, we plan to collect data until at least March 2025. This will give us enough reliable data to draw up our report and recommendations for curbing the phenomenon.
Project co-authors
Denis Neyens
As the originator of the development of hydro-geophysical probes (SMD, Patent FR2993055A1- (2012)) and as a manager of innovative projects, I attach particular importance to integrating a multidisciplinary, multi-scale approach into my projects, based on cross-referencing complementary data (geophysical, hydrogeological, geochemical, etc.).
My expertise is based on over fifteen years’ experience of analysing and interpreting data in order to provide innovative solutions for managing groundwater, particularly in coastal areas affected by saline intrusions.
I’m in charge of European scientific projects within imaGeau, and I’m currently developing collaborative projects (private/public) on groundwater recharge solutions to limit the impact of droughts and the advance of saline intrusions.
