Estimating Groundwater Availability and Variability in Kilombero Valley, Tanzania
Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
Freshwater resources are subject to increasing pressure from a local to global scale. For many parts of the world groundwater is central to increasing water and food security. This is especially the case in regions such as the Kilombero Valley, Tanzania with highly variable or seasonal climates resulting in irregular access to surface water. With the background of scarce and deficient data on groundwater resources and the essential need of such information for wise management, this study aims at estimating the groundwater availability and variability in the Kilombero River Basin, Tanzania. A data set of drill logs provided information on soil types and related values of specific yield; depth of water tables; and depth to bedrock. These data enabled estimations of drainable water and (together with aquifer area) also quantification of the total groundwater volume. The latter was estimated to range between 48 km3 and 357 km3. The values are reasonable as an order of magnitude compared to previous quantifications and the annual water cycle in the valley. The spatial variability in drainable water was less than expected likely due to a high concentration of data points around the floodplain such that they have a similar physical setting. That mainly the valley bottom was covered by the data set indicates that findings reported here might be more appropriate for this specific area instead of the entire catchment. The methods applied give more uncertain results in high elevation areas with less aquifer depths, which could also be part of the explanation for the low spatial variability. However, a low variability indicates a homogenous access to groundwater on a regional level that should be positive in terms of mitigating competition over water. Due to uncertainties with the groundwater estimations, these results should not be overly interpreted but preferably used to indicate potential pathways forward for improvements of quantification approaches. Despite the wide uncertainty ranges the groundwater volumes that are easily accessible in the Kilombero Valley are not unlimited. In order to avoid inappropriate use of the groundwater resources, aquifer data must be considered in land-water management. Otherwise, conflicts are likely to increase due to competition over land and water resources.
Place, publisher, year, edition, pages
2014. , 31 p.
IdentifiersURN: urn:nbn:se:su:diva-103144OAI: oai:DiVA.org:su-103144DiVA: diva2:715840