Estimating groundwater recharge on the southern slope of Mount Kilimanjaro, Tanzania

Lwimbo, Zuberi D.; Komakech, Hans C.; Muzuka, Alfred N. N.

doi:10.1007/s12665-019-8690-5

Cited by 9 publications

(6 citation statements)

References 39 publications

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“…During the dry season, no rainfall surplus was observed, and it obeyed this rule of thumb that, ([P − Ro] − PET ≤0), and there was no groundwater recharge in all the two basins regardless of the difference in climate and geology. Groundwater recharge occurred whenever rainfall minus runoff was larger than the PET, obeying the equation ([P − Ro] − PET >0), as discussed previously [17,30,45], and it usually happened during the rainy season. This is because, during the rainy season, the net rainfall is usually positive.…”

Section: Discussionmentioning

confidence: 67%

“…The consequences of land cover dynamics on catchment hydrology have equally been conducted in the Little Ruaha River catchment [16]. Some studies, albeit scanty, that aimed at assessing the impact of land cover changes on groundwater recharge in Tanzania have been carried out in the northern part of Tanzania recently [17,18]. Nonetheless, the paucity of studies on the implication of climate variability/change and land use/cover changes on natural groundwater recharge, considering the difference in geology and climate in responding to such perturbations, remains ostensibly clear.…”

Section: Background Informationmentioning

confidence: 99%

“…Potential evapotranspiration was calculated using the Penman-Monteith (PM) method and the Hargreaves-Samani (HS) method. The combination of the two methods was chosen to assess the significance of the claims on PET overestimation and underestimation [17,30]. Reportedly, the two temperature-based PET methods (i.e., PM and HS) are as reliable as physically based methods [43,44].…”

Section: Potential Evapotranspirationmentioning

confidence: 99%

“…Curve numbers for various land covers from the study areas as adopted from previous studies[17,30,41].…”

mentioning

confidence: 99%

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Natural Groundwater Recharge Response to Climate Variability and Land Cover Change Perturbations in Basins with Contrasting Climate and Geology in Tanzania

Mussa

Mjemah

Machunda

2021

Earth

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The response of aquifers with contrasting climate and geology to climate and land cover change perturbations through natural groundwater recharge remains inadequately understood. In Tanzania and elsewhere in the world, studies have been conducted to assess the impact of climate change and variability, and land use/cover changes on stream flow using different models, but similar studies on groundwater dynamics are inadequate. This study, therefore, examined the influence of land use/cover and climate dynamics on natural groundwater recharge in basins with contrasting climate and geology in Tanzania, applying the modified soil moisture balance method, coupled with the curve number (CN). The method hinges on the balance between the incoming water from precipitation and the outflow of water by evapotranspiration. The different parameters in the soil moisture balance method were computed using the Thornthwaite Water Balance software. The potential evapotranspiration (PET) was calculated using the daily maximum and minimum temperatures, utilizing two-temperature-based PET methods, Penman–Monteith (PM) and Hargreaves–Samani (HS). The rainfall data were obtained from the gauging stations under the Tanzania Meteorological Agency and some additional data were acquired from climate observatories management by water basins. The results show that there has been a quasi-stable CN in the Singida semi-arid, fractured crystalline basement aquifer (74.2 in 1997, 73.64 in 2005, and 73.87 in 2018). In the Kimbiji, humid, Neogene sedimentary aquifer, the CN has been steadily increasing (66.69 in 1997, 69.08 in 2008, and 71.42 in 2016), indicating the rapid land cover changes in the Kimbiji aquifer as compared to the Singida aquifer. For the Kimbiji humid aquifer, the PET calculated using the Penman–Monteith (PM) method for the 1996/1997, 2007/2008, and 2015/2016 hydrological years were 1156.5, 1079.5, and 1143.9 mm/year, respectively, while for the Hargreaves–Samani (HS) method, the PET was found to be 1046.1, 1138.3, and 1204.4 mm/year for the 1996/1997, 2007/2008, and 2015/2016 hydrological years, respectively. For the Singida semi-arid aquifer, the PM PET method resulted in 2083.3, 2053.6, and 1875.4 mm/year for the 1996/1997, 2004/2005, and 2017/2018 hydrological years, respectively. The HS method produced relatively lower PET values for the semi-arid area (1839.4, 1814.7, and 1710.2 mm/year) for the 1996/1997, 2004/2005, and 2017/2018 hydrological years, respectively. It was equally revealed that the recharge and aridity indices correspond with the PET calculated using two temperature-dependent methods. The decline of certain land covers (forests) and increase in others (built-up areas) have contributed to the increase in surface runoff in each study area, possibly resulting in the decreasing trend of groundwater recharge. An overestimation of the PET using the HS method in the Kimbiji humid aquifer was observed, which was relatively smaller than the overestimation of the PET using the PM method in the Singida semi-arid aquifer. Despite the difference in climate and geology, the response of the two aquifers to rainfall is similar. The combined influence of climate and land cover changes on natural groundwater recharge was observed to be prominent in the Kimbiji aquifer, while only climate variability appreciably influences natural groundwater recharge in the Singida semi-arid aquifer. El Nino and the Southern Oscillation as part of the climate variability phenomenon dwarfed the time lags between rainfall and recharge in the two basins, regardless of their difference in climate and geology.

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Section: Discussionmentioning

confidence: 67%

Section: Background Informationmentioning

confidence: 99%

Section: Potential Evapotranspirationmentioning

confidence: 99%

“…Curve numbers for various land covers from the study areas as adopted from previous studies[17,30,41].…”

mentioning

confidence: 99%

See 2 more Smart Citations

Natural Groundwater Recharge Response to Climate Variability and Land Cover Change Perturbations in Basins with Contrasting Climate and Geology in Tanzania

Mussa

Mjemah

Machunda

2021

Earth

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“…These hotspots can contribute significantly to overall recharge, with 30% of annual GWR occurring in just 10% of the hillslope area. These hotspot locations are mostly determined by the dynamic factors that drive the recharge pattern spatially, such as the size of rainstorms in relation to the water storage capacity of the soil [77,78].…”

Section: Slope Gradientmentioning

confidence: 99%

Mapping of Groundwater Recharge Zones in Hard Rock Aquifer through Analytic Hierarchy Process in Geospatial Platform

Subramani,

Kamaraj,

Saravana Kumar

et al. 2024

Water

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Extensive use of groundwater is a result of the growing population; in relation to this, studies have focused on groundwater conservation measures. This study identified groundwater artificial recharge zones (GWARZs) in the upper Manimuktha sub-basin through the application of remote sensing and GIS. A spatial analysis using the analytical hierarchical process (AHP) and weighted overlay analysis (WOA) was employed by integrating several spatial thematic layers such as geology, geomorphology, aquifer thickness, lineament density (LD), drainage density (DD), soil, slope, rainfall, and land use/land cover (LULC) in order to classify the GWARZs. The geomorphology along with lithology, higher aquifer thickness, low lineament densities, higher drainage densities, and gentle slope regions, were identified as suitable areas for artificial recharge zones. The study area was divided up into five classifications based on the integration analysis: excellent (41.1 km2), good (150.6 km2), moderate (123.9 km2), bad (125.5 km2), and very poor (57.7 km2). Excellent and good GWARZs were identified in the eastern and central regions of the study area. The final outcomes of this research were evaluated with seasonal electrical conductivity (EC) variations. The majority of samples with minor seasonal EC variations were observed in the excellent and good GWARZ categories. The results showed that the spatial analysis tool is useful for GWARZ delineation and sustainably managing groundwater resources.

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Recharge, élévation retardée du niveau des eaux souterraines et rendement spécifique au sein de l’aquifère karstique du Trias de la montagne Kopa, dans les Carpates occidentales, Slovaquie

Malík

Coplák²,

Švasta

et al. 2020

Hydrogeol J

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Estimating groundwater recharge on the southern slope of Mount Kilimanjaro, Tanzania

Cited by 9 publications

References 39 publications

Natural Groundwater Recharge Response to Climate Variability and Land Cover Change Perturbations in Basins with Contrasting Climate and Geology in Tanzania

Natural Groundwater Recharge Response to Climate Variability and Land Cover Change Perturbations in Basins with Contrasting Climate and Geology in Tanzania

Mapping of Groundwater Recharge Zones in Hard Rock Aquifer through Analytic Hierarchy Process in Geospatial Platform

Recharge, élévation retardée du niveau des eaux souterraines et rendement spécifique au sein de l’aquifère karstique du Trias de la montagne Kopa, dans les Carpates occidentales, Slovaquie

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