Hydrogeological characterisation of water table rise — Touba

01Context

Senegal's second largest agglomeration, Touba has experienced rising shallow water table for several years, affecting buildings, road infrastructure and residents' living conditions.

The Directorate for Water Resources Management and Planning (DGPRE), funded by the Consolidated Investment Budget, commissioned EAU-GEF to conduct a study to document the phenomenon and understand its mechanisms.

02Challenges

Beyond visible damage, the challenge was to distinguish the causes of the phenomenon — natural recharge, rapid urbanisation, lack of outflow — to avoid inadequate responses.

The heritage and religious sensitivity of the site required a rigorous, documented and defensible approach with local and religious authorities.

03Mission objectives

• Characterise the behaviour of the shallow aquifer and its interactions with the urban environment
• Map sectors exposed to water table rise
• Identify the main aggravating factors
• Formulate ranked management and drainage recommendations

04Services delivered by EAU-GEF

• Collection, archiving and critical analysis of existing hydrogeological data
• Field campaign: inventory of water points and piezometric measurements
• Geophysical investigations to clarify aquifer geometry
• GIS processing and production of vulnerability maps
• Drafting of a diagnostic report and recommendations

05Approach & methodology

The approach combined desk study, field observations and geophysical imaging, cross-referenced within a geographic information system.

This integrated approach links point measurements to an overall understanding of aquifer behaviour at the agglomeration scale.

06Results & added value

The study provided clear insight into aquifer behaviour and operational mapping of sensitive sectors, forming a decision-support basis for authorities.

It strengthens the capacity of local stakeholders to plan appropriate drainage measures and demonstrates EAU-GEF's expertise in water table issues in urban environments.