Saraya, Senegal

Background

Saraya, located in eastern Senegal near the borders with Mali and Guinea, lies within an area of intense gold exploration and mining activity. The region hosts both large-scale industrial operations and numerous artisanal mining sites, which have expanded rapidly in recent years. While the sector supports local livelihoods, it also places growing pressure on surface and groundwater resources through increased water abstraction, sedimentation, and contamination. The area's crystalline basement geology and limited perennial surface water make groundwater the primary source for drinking, domestic use, and small-scale processing. Understanding its distribution, quality, and vulnerability has become central to sustainable resource management.

ERT survey setup — Figure 1: Electrical resistivity tomography (ERT) survey being deployed in Badiuola, Senegal.

Figure 2: Market garden in a perennial river channel, showing local water-digging sites used for irrigation during the dry season.

Figure 3: Hammering ERT electrodes into the soil during field setup.

TEM survey setup — Figure 4: TEM survey instrument being moved between measurement sites during data acquisition.

ERT survey at school — Figure 5: Conducting an ERT survey at the local primary school.

Well — Figure 6: Local private well where users collect water using a bucket.

Water level sensors — Figure 7: Modifying water level sensors prior to installation in the well.

Sensor — Figure 8: Installing a post to mount the sensor transmitter for LoRa data transmission.

Soil sampling — Figure 9: Mounting the sensor transmitter on the pole.

Community workshop — Figure 10: Water samples collected for analysis of major ions and trace metals.

Field overview — Figure 11: Sharing project results with national water authorities (DGPRE).

Field activities

The Saraya fieldwork was carried out during the late dry season. Access required coordination with local authorities, community representatives, to ensure safe operations. Field teams installed long-term groundwater monitoring equipment and collected complementary datasets including manual water levels, and field EC/pH readings. These observations were supported by targeted TEM and ERT data designed to delineate weathered zones and assess viable groundwater resources.

Groundwater monitoring stations were established in community wells to track seasonal variations in water levels and conductivity. Laboratory analyses of selected samples assessed key parameters including major ions and trace metals. The data were compiled into an integrated geodatabase to support both local water authorities and ongoing environmental compliance programs.

Outcomes and relevance

The Saraya campaign provided a clearer picture of how mining activities intersect with local hydrogeological systems in eastern Senegal. By combining resistivity mapping with continuous water-level and quality monitoring, the work helped identify vulnerable zones and potential pathways for contaminant migration. The findings contribute to a growing regional dataset supporting responsible mining practices and groundwater protection. Beyond technical outcomes, the monitoring program established a foundation for long-term collaboration between research institutions and governmental authorities.