Alluvial corridors of ephemeral river systems provide viable opportunities for natural water storage in dry lands. Whilst alluvial corridors are widely recognized as water buffers, particularly for areas experiencing constant water scarcity, little research has been undertaken in Sub-Saharan Africa to explore their hydrological variability and water resource potential as alternative water sources for nearby communities. This study investigated the water flow behavior and storage potential of an ephemeral river system in the Mara Basin of Kenya for purposes of supporting water resources development and ecological sustainability. The water flow processes-including the recharge rates and water loss processes-from existing sand storage systems were established through monitoring of ground and surface water levels. Water samples along the alluvial corridor were collected and analyzed for major ions and isotopic signatures required to establish the water storage dynamics. The storage potential was estimated through Probing and Electrical Resistivity Tomography techniques, augmented with insitu measurements of hydraulic conductivities and channel bed porosities. The mean annual storage volume in the alluvium of the study reach was estimated at 1.1 Mm 3 , potentially capable of providing for the annual domestic and livestock water demands of the area. Transmission losses into the alluvium beneath the ephemeral channel-bed were noted to attenuate the flood peak discharges, depending on the level of saturation of the alluvial bed. However, water storage in the alluvium was subject to losses through evapotranspiration and seepage through fractured bedrocks. The study demonstrated the potential of alluvial corridors as water storage buffers providing alternative water sources to communities within the dry land regions with water scarcity, thereby to supporting ecosystem sustainability.

Information on the soil moisture content in the soil is important for planning both for farmers and agricultural water managers. The availability of this information is however limited owing to the expensive nature of in-situ soil moisture measurements and cloud conditions that limits satellite derivation of soil moisture and the availability of satellite derived soil moisture at coarse resolutions limiting their application at local scale. This study applies existing downscaling technique which makes use of vegetation indices and land surface temperature. The study compounds the technique with Harmonic Analysis of Time Series (HANTS) to provide continuous high-resolution soil moisture. The case study area is the state of Nebraska and the low-resolution soil moisture used is advanced Scatterometer (ASCAT). The use of HANTS successfully produced daily soil moisture estimates without degrading the accuracy of the soil moisture at 0.09m3/m3. The Precision however, was observed to be slightly degraded owing to seasonal variations and the different rooting depths within which the vegetation draws soil moisture from. Whereas the study has been conducted in Nebraska, the same can be replicated in regions with limited soil moisture measurements. The information is paramount for crop production forecasting, drought assessment and crop water management since it provides near real time information. This study shows that soil moisture downscaling can improve the resolution without degrading the accuracy. This accuracy was found to be within the threshold required for global climate observation systems (GCOS) which is set at 20% of the saturated water content.