Water Balance and Level Change of Lake Babati, Tanzania: Sensitivity to Hydroclimatic Forcings

Abstract

Abstract:We develop and present a novel integrated water balance model that accounts for lake water-groundwater interactions, and apply it to the semi-closed freshwater Lake Babati system, Northern Tanzania, East Africa. The model was calibrated and used to evaluate the lake level sensitivity to changes in key hydro-climatic variables such as temperature, precipitation, humidity and cloudiness. The lake response to the Coupled Model Intercomparison Project, Phase 5 (CMIP5) output on possible future climate outcomes was evaluated, an essential basis in understanding future water security and flooding risk in the region. Results show high lake level sensitivity to cloudiness. Increased focus on cloud fraction measurement and interpretation could likely improve projections of lake levels and surface water availability. Modelled divergent results on the future (21st century) development of Lake Babati can be explained by the precipitation output variability of CMIP5 models being comparable to the precipitation change needed to drive the water balance model from lake dry-out to overflow; this condition is likely shared with many other East African lake systems. The developed methodology could be useful in investigations on change-driving processes in complex climate-drainage basin-lake systems, which are needed to support sustainable water resource planning in data scarce tropical Africa.

Water demand and effects of climate change in the middle Kafue River basin

“…However, according to Cook and Bakker (2012), protection from the risk associated with flood and drought is generally considered a key determinant of water security from an agricultural perspective. However, only the study on Lake Babati, conducted by Mbanguka et al (2016), was found to address the water and climate models together.…”

A Decade of Data‐Driven Water Budgets: Synthesis and Bibliometric Review

“…Most of the studies we reviewed focused on a water budget from a past research site, perhaps mentioning at the importance of climate change (e.g., Hughes et al., 2022), but did not incorporate bias‐corrected regional climate projections into the data‐driven water budgets. One study that was screened by our search criteria evaluated the sensitivity of the Lake Babati system in East Africa to changes in key hydro‐climatic variables using the Coupled Model Intercomparison Project, Phase 5 (CMIP5) output to understand future risks in water security and flooding (Mbanguka et al., 2016). Dynamic water budget accounting should integrate bias‐corrected regional climate projects to account for the fundamental processes of climate impact on water balance conditions.…”

Using the water balance approach to understand pool dynamics along non-perennial rivers in the semi-arid areas of South Africa

“…Where A(t) is the surface area of the pool obtained using the relationship between surface area and water storage. Evaporation from the pool (E(t)) was estimated similarly to P(t) with evaporation rates derived using the Penman (1948) method, based on weather station data, as it is a commonly-used method for estimating open water evaporation (Mbanguka et al, 2016;Yihdego and Webb, 2018).…”

“…The water balance approach has been widely used to represent and predict changes in water storage of water bodies (Ali et al, 2015). This approach is based on the law of conservation and has been used to understand water fluxes that influence water body dynamics and simulate the water availability in hydrological systems, such as lakes and wetlands (Gronewold et al, 2020;Mbanguka et al, 2016). The water balance, like other methods, requires data or estimates of each of the hydrological components (evaporation, precipitation, surface water in-and outflows and groundwater in-and outflows).…”