Ongoing monitoring and recommendations to combat the salt wedge in Agadir
Customer needs
Customer issues
The Agadir region has a semi-arid climate. Whatever the time of year, rainfall is low, which means that groundwater is often insufficiently recharged. But the region, which is one of Europe’s biggest tomato producers, relies heavily on groundwater forits agricultural needs.
For more than 20 years now, these aquifers have been over-exploited, particularly in the coastal zone near Agadir. For some years now, the Souss Massa water basin agency has been observing the intrusion of saline water into the coastal aquifer.
That’s why we’ve been asked to monitor the salt-water wedge very closely in order to draw up recommendations to prevent the phenomenon from worsening.
Heritage :
- More than a hundred agricultural boreholes
- A wellfield at Imzar used for drinking water, with annual volumes of around 4 million m3
- 2 SMDs at depths of 80 and 140 m
The Imageau solution
Installation of the SMD monitoring system
To control the saltwater wedge phenomenon as effectively as possible, it is important to gather as much qualitative data as possible to understand the dynamics of saltwater intrusion:
- What factors encourage it?
- Is the water table too low?
- What is the impact of agricultural drilling on the saltwater wedge? Does pumping exacerbate the phenomenon?
etc.
To understand and monitor saline intrusion into the water table, we installed our patented SMD Intrusion monitoring system and collected data for 3 years. At the same time, we analysed and interpreted the data in order to understand and determine the parameters impacting on the saltwater wedge.
Formulation of recommendations to slow the advance of the salt wedge
Thanks to the wide range of information gathered during this observation period, we realised that the salt wedge tended to arrive from the north of the Chtouka nappe. There are many agricultural boreholes in this area, as well as boreholes for the local drinking water supply. In particular, we detected an increase in the volume of water being extracted from these boreholes, which was causing the saline layer within the aquifer to expand.
We therefore formulated a number of recommendations to the Souss Massa water basin agency to encourage more sustainable management of exploitation. Continuous monitoring of the salinity of the water table enables them toadapt their operations in certain critical areas where the boreholes are located, so as not to exacerbate the salinity problem.
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 and 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.
As a European scientific project manager at imaGeau, I am currently developing collaborative projects (private/public) on groundwater recharge solutions to limit the impact of droughts and the advance of saline intrusions.
N2E – Nord Est Electronique
This Moroccan company specialises in telecommunications network infrastructure and engineering, and in technological solutions applied to the water cycle, the environment and meteorology. They assisted us with the installation of our SMD systems.
Are you a local authority or operator affected by rising salt water levels?
The project in pictures
