Depollution of Hann Bay — sanitation

01Context

Hann Bay is the subject of a large-scale depollution and sanitation programme.

The implementation of the facilities required mastery of the geological and hydrogeological context.

02Issues

Reconciling development and preservation required rigorous evaluation of impacts on environments and resources.

Regulatory compliance and social acceptability of the project were central to the approach.

03Mission objectives

• Determine the hydrogeological influence of tides
• Assess hydrological consequences on earthworks
• Quantify aquifer drawdown rates
• Formulate recommendations for the facilities

04Services provided by EAU-GEF

• Geological and hydrogeological study of the coastal zone
• Analysis of tidal influence
• Quantification of aquifer drawdown
• Recommendations for facility implementation

05Approach & methodology

The methodology articulated field investigations, analyses and structured risk evaluation, up to the management plan.

Each conclusion was supported by measured data to ensure the robustness of the diagnosis.

06Results & added value

The study provided the contracting authority with a diagnosis and operational recommendations to manage impacts.

It reinforces EAU-GEF's role on sensitive environmental issues.