These units are producing aquifers in the Plateau uplands province, and potentially could provide useable quantities of water within the sub-basin. However, the eastern part of the sub-basin is covered with volcanics. Groundwater occurs in the various volcanic flows in cinder beds, weathered zones, and fracture zones. Water is produced from seeps, springs, and shallow, low-yield wells. The Black River sub-basin is almost entirely covered by volcanics.
Water is available from low-yield wells, springs, and seeps.
The few wells completed in these basalts are widely scattered and used for stock and domestic consumption.