The need for evidence-research to inform policy decisions on land and water development activities in the Nile riparian countries motivated this study to determine levels and constituents of suspended sediment loading in one transboundary river and how they relate to the environmental flow requirements. Could catchment degradation be causing increased sedimentation of the water resources in the Mara River, an international river shared by Kenya and Tanzania, part of the larger Upper Nile River Basin replenishing the waters of Lake Victoria? The methodology shows on how baseline data were collected, total suspended sediment load and corresponding turbidity in the water samples determined, the concentrations of trace metals in dried sediments were identified and the results were discussed. It was concluded that the increased levels of sediment pollution in the upper reach could be attributed to poor anthropogenic practices and settlement in forest catchment that resulted in soil erosion, run-off from point sources, shopping centres, dump sites, sludge lagoons and high organic matter in the swamps upstream. Recommended for policy-makers, development and Transboundary water managers