Groundwater Assessment, Bentiu POC

Case studies

Groundwater Assessment, Bentiu POC

South Sudan March 2016

The International Organisation for Migration (IOM) commissioned Groundwater Relief to assess the groundwater infrastructure at the Bentiu POC, hosting over 120,000 people at the time of the assessment.

IOM has been very pleased with the work done by Groundwater Relief. The groundwater investigation was sound and comprehensive, with results clearly presented and understandable for technical and non-technical audiences, which allowed IOM to advocate for the improved provision of safe drinking water for the internally displaced populations residing at the Protection of Civilians (PoC) camp in Bentiu. Antonio Torres, WASH Coordinator, IOM, South Sudan Antonio Torres, WASH Coordinator, IOM, South Sudan

Groundwater Relief’s assessed the capacity and efficiency of each of the boreholes at the camp through carrying out pumping tests on the existing boreholes and borehole camera surveys to investigate borehole condition. Recommendations were made to improve the utilisation of the existing groundwater supply infrastructure (primarily by installing higher capacity pumps and lowering pump intake depth) improving output from the existing boreholes by an additional 50%, dramatically increasing water output for the camp population.

The work resulted in a robust hydrogeological conceptual model of the site area being developed. Two distinct aquifer units were observed, ‘upper’ and ‘lower’, each with differing hydraulic properties and water chemistry, separated by a laterally extensive (semi) confining clay layer. Geological logs were built into a 3D geological model, which was used to investigate this two aquifer system. This advanced hydrogeological understanding will allow long term impacts of groundwater extraction to be understood better, and inform the drilling of future boreholes.

In addition a groundwater monitoring programme was established for the site using automatic and manual instrumentation. Local and international site staff were trained in basic hydrogeological data collection, to ensure the long term success of the monitoring. This monitoring programme will provide highly valuable information about the long-term aquifer water levels and allow IOM to make technically sound decisions regarding future groundwater supply at the camp.