Water security assessment in ungauged regions using the water balance and water footprint concepts and satellite observations

Abstract

Water security assessments often rely on outputs from hydrological models that are applicable only in gauged regions where there are river discharge data to constrain the models. Therefore, there is an urgent need to explore new methods for assessing water security in ungauged regions. This study proposes the use of the water balance and water footprint concepts and satellite observations to assess water security in Anglophone Cameroon, which is an example of a typically ungauged region. Specifically, the study assesses demand-driven water scarcity in terms of blue and green water scarcities and population-driven water scarcity quantified using the Falkenmark index across all districts in Anglophone Cameroon. The study also performs a spatiotemporal trend analysis of precipitation and temperature in the study area using the Mann–Kendall test. Precipitation trend analysis returns varying strengths and magnitudes for different districts unlike temperature which demonstrates an upward trend in all districts. The water security assessment shows that blue water scarcity is substantially low across most districts, whereas population-driven water scarcity is observed in densely populated districts (<1,700 m3/capita/year). The results from this study suggest that the proposed method may be used to assess water security in ungauged regions irrespective of climate or population size. HIGHLIGHTS A methodology to identify water scarcity hotpots in ungauged regions was proposed.; The method was used to demonstrate that the population-driven blue water scarcity is high in urban areas.; The methodology also revealed areas that may be suitable for agricultural expansion to enhance food security.;

Keywords

• blue water scarcity
• evapotranspiration
• falkenmark index
• green water scarcity
• soil moisture storage