Groundwater recharge and potential exploitation in the Densu basin, Southwestern Ghana

Duah, Anthony A.; Akurugu, Bismark Awinbire; Darko, Philip K.; Manu, Evans; Mainoo, Patrick A.

doi:10.1016/j.jafrearsci.2021.104332

Cited by 6 publications

(7 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In the calculation, we utilized the average annual precipitation of 1500 mm as reported by Dickson et al [51]. In addition, the average chloride concentration in precipitation (1.13 mg/L) was taken from Duah et al [14], which was estimated using records from meteorological stations in the adjacent Densu Basin. The chloride concentration in groundwater was obtained from 56 samples collected by ourselves [28].…”

Section: Groundwater Recharge Estimation Using Cmb Methodsmentioning

confidence: 99%

“…The estimate of 10.7% mean recharge of the annual precipitation from the CMB is generally consistent with the mean basin recharge of 16% reported by the Water Resources Commission of Ghana, and our results are consistent with other studies carried out in different parts of Ghana. For example, Yidana et al [3] estimated an average recharge of 7.6% of annual precipitation using numerical groundwater flow models in south-east Ghana, while Afrifa et al [2], Obuobie et al [8], and Duah et al [14] reported similar figures in northern and southern Ghana, respectively.…”

Section: Groundwater Recharge Estimatesmentioning

confidence: 98%

“…[1] and Duah et al [14], respectively. Bivariate plots were used to construct surface water and groundwater regression lines using the δ 18 O vs. δ 2 H plot.…”

Section: Data Collection and Analysismentioning

confidence: 99%

“…However, some uncertainties are expected due to other potential sources of Cl − in groundwater that are not considered in the calculation. The main assumption for using the CMB is that the source of Cl − in groundwater is mainly from precipitation and that Cl − behaves conservatively, not being leached or absorbed from aquiferous sediments and not being affected by chemical reactions [2,8,14]. Other sources of Cl − , including deposition from marine aerosols and pollution from sewage, might contribute to the Cl − loads as these wells are public wells exposed to unregulated disposal of solid and liquid waste on-site.…”

Section: Groundwater Recharge Estimatesmentioning

confidence: 99%

“…In various geological terrains around the world, the CMB method has been employed to evaluate groundwater recharge [8,[14][15][16][17]. The CMB method was postulated by Eriksson and Khunakasem [15], who used it to estimate groundwater recharge in the saturated zone of a coastal plain in Israel.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Stable Isotopes and Water Level Monitoring Integrated to Characterize Groundwater Recharge in the Pra Basin, Ghana

Manu,

De Lucia,

Akiti

et al. 2023

Water

Self Cite

View full text Add to dashboard Cite

In the Pra Basin of Ghana, groundwater is increasingly becoming the alternative water supply due to the continual pollution of surface water resources through illegal mining and indiscriminate waste discharges into rivers. However, our understanding of hydrogeology and the dynamics of groundwater quality remains inadequate, posing challenges for sustainable water resource management. This study aims to characterize groundwater recharge by determining its origin and mechanism of recharge prior to entering the saturated zone and to provide spatial estimates of groundwater recharge using stable isotopes and water level measurements relevant to groundwater management in the basin. Ninety (90) water samples (surface water and groundwater) were collected to determine stable isotope ratios of oxygen (δ18O) and hydrogen (δ2H) and chloride concentration. In addition, ten boreholes were installed with automatic divers to collect time series data on groundwater levels for the 2022 water year. The Chloride Mass Balance (CMB) and the Water Table Fluctuation (WTF) methods were employed to estimate the total amount and spatial distribution of groundwater recharge for the basin. Analysis of the stable isotope data shows that the surface water samples in the Pra Basin have oxygen (δ18O) and hydrogen (δ2H) isotope ratios ranging from −2.8 to 2.2‰ vrs V-SMOW for δ18O and from −9.4 to 12.8‰ vrs V-SMOW for δ2H, with a mean of −0.9‰ vrs V-SMOW and 0.5‰ vrs V-SMOW, respectively. Measures in groundwater ranges from −3.0 to −1.5‰ vrs V-SMOW for δ18O and from −10.4 to −2.4‰ vrs V-SMOW for δ2H, with a mean of −2.3 and −7.0‰ vrs V-SMOW, respectively. The water in the Pra Basin originates from meteoric source. Groundwater has a relatively depleted isotopic signature compared to surface water due to the short residence time of infiltration within the extinction depth of evaporation in the vadose zone. Estimated evaporative losses in the catchment range from 51 to 77%, with a mean of 62% for surface water and from 55 to 61% with a mean of 57% for groundwater, respectively. Analysis of the stable isotope data and water level measurements suggests a potential hydraulic connection between surface water and groundwater. This hypothesis is supported by the fact that the isotopes of groundwater have comparatively lower values than surface water. Furthermore, the observation that the groundwater level remains constant in months with lower rainfall further supports this conclusion. The estimated annual groundwater recharge in the catchment ranges from 9 to 667 mm (average 165 mm) and accounts for 0.6% to 33.5% (average 10.7%) of mean annual precipitation. The total estimated mean recharge for the study catchment is 228 M m3, higher than the estimated total surface water use for the entire Pra Basin of 144 M m3 for 2010, indicating vast groundwater potential. Overall, our study provides a novel insight into the recharge mechanism and spatial quantification of groundwater recharge, which can be used to constrain groundwater flow and hydrogeochemical evolution models, which are crucial for effective groundwater management within the framework of the Pra Basin’s Integrated Water Resources Management Plan.

show abstract

Section: Groundwater Recharge Estimation Using Cmb Methodsmentioning

confidence: 99%

Section: Groundwater Recharge Estimatesmentioning

confidence: 98%

“…[1] and Duah et al [14], respectively. Bivariate plots were used to construct surface water and groundwater regression lines using the δ 18 O vs. δ 2 H plot.…”

Section: Data Collection and Analysismentioning

confidence: 99%

Section: Groundwater Recharge Estimatesmentioning

confidence: 99%