Dual Echo Sounder Bathymetric Survey for Enhanced Management of Ruiru Reservoir, Kenya

Lake and reservoirs have significant global function as a source of fresh water and they sustain various activities such as agriculture, fisheries, and recreation.  They play a critical role in distributing spatially and temporally the meagre water resources in most watersheds.  However, the design lifespans of reservoirs are being threatened by volume loss despite their critical role in development.  Being able to regularly monitor this volume loss is an important aspect of reservoir sustainable management.  In this paper, we present a method that combines dual echo sounding and Geographic Information System (GIS) in bathymetric survey to determine the current volume of Ruiru reservoir in central Kenya.  In the reservoir, we showed that the current volume is 2,564,590 m 3 compared to the original volume of 2,980,000 m 3 , which implies that the reservoir has lost about 14% of its recorded volume.  Furthermore, the study established, the Depth- Surface Area - Volume relationships, important tools for reservoir management.