Safe drinking water is critical to human health and development. In rural sub‐Saharan Africa, most improved water sources are boreholes with handpumps; studies suggest that up to one third of these handpumps are nonfunctional at any given time. This work presents findings from a secondary analysis of cross‐sectional data from 1509 water sources in 570 communities in the rural Greater Afram Plains (GAP) region of Ghana; one of the largest studies of its kind. 79.4% of enumerated water sources were functional when visited; in multivariable regressions, functionality depended on source age, management, tariff collection, the number of other sources in the community, and the district. A Bayesian network (BN) model developed using the same data set found strong dependencies of functionality on implementer, pump type, management, and the availability of tools, with synergistic effects from management determinants on functionality, increasing the likelihood of a source being functional from a baseline of 72% to more than 97% with optimal management and available tools. We suggest that functionality may be a dynamic equilibrium between regular breakdowns and repairs, with management a key determinant of repair rate. Management variables may interact synergistically in ways better captured by BN analysis than by logistic regressions. These qualitative findings may prove generalizable beyond the study area, and may offer new approaches to understanding and increasing handpump functionality and safe water access.
Quantifying the regulation of precipitation-associated vegetation dynamics on land surface water balance poses a particular challenge in current eco-hydrological studies because terrestrial ecological processes interact with hydrological processes, and both are subject to precipitation change. The objective of this study is to examine how precipitation change-associated vegetation dynamics may regulate catchment water balance in a semiarid to arid mountain ecosystem. To achieve this objective, R-RHESSys, which is short for rasterised regional hydro-ecological simulation system, a distributed hydro-ecological model, was applied to the Cleve Creek watershed in the eastern Nevada, USA. Simulation results from two scenarios based on altered precipitations were compared, respectively, to those from a baseline scenario based on observed precipitations. Our results suggest that R-RHESSys can accurately simulate catchment water balance and vegetation dynamics in the study area. In addition, we found that (i) precipitation-associated shifts in leaf canopy can help reduce flood potentials during wet years or sustain baseflow during dry years through changing evapotranspiration (ET); (ii) precipitation-associated decrease in leaf canopy and consequent decrease in ET do not always increase streamflow and vice versa. The regulation of precipitation-associated vegetation dynamics on streamflow is subject to initial soil water condition; (iii) vegetation-associated shifts in plant transpiration play an important role in regulating soil water content and streamflow generation in the semiarid and arid mountain watershed; and (iv) the regulation of precipitation-associated shift in leaf canopy on ET is more pronounced in the ridges of watershed than in valleys. In contrast, its regulation on subsurface flow generation is more remarkable in valleys than in the ridges of watershed.
Evaluating groundwater levels and recharge patterns is part of sustainably managing the water supply and predicting the possibility of water shortages, especially in light of climate change, extreme events (floods/droughts), increasing population and development. In the northern region of Ghana, groundwater is increasingly relied upon as a source of potable water for rural populations, but seasonal and inter-annual fluctuations of groundwater levels and recharge patterns are not always known. The fluctuation of groundwater levels on a seasonal basis shows that groundwater levels at all sites increase in response to seasonal precipitation. On an annual basis, all sites show an overall net decline of groundwater levels over the study period, which may be associated with below-average departures of precipitation during five of the seven study years. The variability of recharge patterns among five sites is attributed to the spatio-temporal variability of precipitation and hydrogeologic site uniqueness. The overarching potential benefit of this study is to facilitate OPEN ACCESS Climate 2015, 3 2 closing knowledge gaps and contribute to a foundation for a more robust evaluation of groundwater resources in the area, especially as more data become available.
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