Spatial modelling of groundwater quality across a land use and land cover gradient in Limpopo Province, South Africa

Dube, Timothy; Shoko, Cletah; Sibanda, Mbulisi; Baloyi, Moses M.; Molekoa, Mmasabata Dolly; Nkuna, Dimakatso; Rafapa, Bentley; Rampheri, Berel M.

doi:10.1016/j.pce.2019.102820

Cited by 19 publications

(6 citation statements)

References 24 publications

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“…More than 1.5 billion people around the world are said to be reliant on groundwater for their basic needs [1]. Groundwater, with its potential to deliver water during drought years, remains the most stable and sustainable source of water, particularly where surface water supply is inadequate [2].…”

Section: Introductionmentioning

confidence: 99%

Groundwater Quality Assessment in Aba (Abia State) Using WQI and GIS Techniques

Kanu,

Ugwoha,

Udeh

et al. 2023

AJEE

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Groundwater is considered as the most important source of freshwater for human consumption and activities in the urban environment. The assessment of groundwater quality is critical to avoid the negative effects of polluted groundwater on human health, agriculture, and the economy. In this study, the quality of groundwater in Aba (Abia State), Nigeria was assessed. Thirty-two water samples were taken from sixteen boreholes during the rainy and dry seasons, and analysed for pH, Electrical Conductivity, Total Hardness, Turbidity, Temperature, BOD5, COD, Pb, Cd, Cr, NH3, TDS, SO4, NO3 and PO4. The Weighted Average Water Quality Index (WAWQI) approach was used to compute the Water Quality Index (WQI). Geostatistical analysis methods such as Ordinary Kriging, Empirical Bayesian Kriging (EBK), Inverse Distance Weighting (IDW) and Spline interpolation methods were compared in the spatial evaluation of variable concentrations using ArcGIS. In the dry season, 100% of the borehole locations had Water Quality Index values above 100 which is Unsuitable for drinking purpose. For the rainy season, 87.5% of the borehole locations had WQI values above 100 which is Unsuitable for drinking purpose, 6.25% had WQI which was of very poor quality and 6.25% had WQI values within the range of good water quality between 26 and 50. With a mean error of 0.372483, RMSE of 0.5515, and RMSSE of 1.030492 for the dry season and a mean error of 0.05625, RMSE of 10, and RMSSE of 0.986448 for the rainy season, the EBK interpolation approach was the best fit model for the WQI determination. WQI values for rainy season were generally lower than the WQI values of the dry season, attributable to surface water run-off during the rains.

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Section: Introductionmentioning

confidence: 99%

Groundwater Quality Assessment in Aba (Abia State) Using WQI and GIS Techniques

Kanu,

Ugwoha,

Udeh

et al. 2023

AJEE

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“…In 2012, it was estimated that 842 000 people died of diarrhea due to directly or indirectly consuming poor water quality, of which 43% of the mortality case reported were children. According to Dube, Shoko [13], 29.9% of global freshwater is reserved underground, being a critical source of water supply and a buffer against drought in rural communities, where surface water is limited especially in developing countries [14]. However, most of the rural communities in developing countries are now at threat and vulnerable from the effect of climate change which affects people's daily water availability and consumption.…”

Section: Introductionmentioning

confidence: 99%

An Assessment of Land Use and Land Cover Changes and Its Impact on the Surface Water Quality of the Crocodile River Catchment, South Africa

Samuel¹,

Bett²,

Okpara³

et al. 2022

River Deltas Research - Recent Advances

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The degradation of surface water by anthropogenic activities is a global phenomenon. Surface water in the upper Crocodile River has been deteriorating over the past few decades by increased anthropogenic land use and land cover changes as areas of non-point sources of contamination. This study aimed to assess the spatial variation of physicochemical parameters and potentially toxic elements (PTEs) contamination in the Crocodile River influenced by land use and land cover change. 12 surface water samplings were collected every quarter from April 2017 to July 2018 and were analyzed by inductive coupled plasma spectrometry-mass spectrometry (ICP-MS). Landsat and Spot images for the period of 1999–2009 - 2018 were used for land use and land cover change detection for the upper Crocodile River catchment. Supervised approach with maximum likelihood classifier was used for the classification and generation of LULC maps for the selected periods. The results of the surface water concentrations of PTEs in the river are presented in order of abundance from Mn in October 2017 (0.34 mg/L), followed by Cu in July 2017 (0,21 mg/L), Fe in April 2017 (0,07 mg/L), Al in July 2017 (0.07 mg/L), while Zn in April 2017, October 2017 and April 2018 (0.05 mg/L). The concentrations of PTEs from water analysis reveal that Al, (0.04 mg/L), Mn (0.19 mg/L) and Fe (0.14 mg/L) exceeded the stipulated permissible threshold limit of DWAF (< 0.005 mg/L, 0.18 mg/L and 0.1 mg/L) respectively for aquatic environments. The values for Mn (0.19 mg/L) exceeded the permissible threshold limit of the US-EPA of 0.05 compromising the water quality trait expected to be good. Seasonal analysis of the PTEs concentrations in the river was significant (p > 0.05) between the wet season and the dry season. The spatial distribution of physicochemical parameters and PTEs were strongly correlated (p > 0.05) being influenced by different land use type along the river. Analysis of change detection suggests that; grassland, cropland and water bodies exhibited an increase of 26 612, 17 578 and 1 411 ha respectively, with land cover change of 23.42%, 15.05% and 1.18% respectively spanning from 1999 to 2018. Bare land and built-up declined from 1999 to 2018, with a net change of - 42 938 and − 2 663 ha respectively witnessing a land cover change of −36.81% and − 2.29% respectively from 1999 to 2018. In terms of the area under each land use and land cover change category observed within the chosen period, most significant annual change was observed in cropland (2.2%) between 1999 to 2009. Water bodies also increased by 0.1% between 1999 to 2009 and 2009 to 2018 respectively. Built-up and grassland witness an annual change rate in land use and land cover change category only between 2009 to 2018 of 0.1% and 2.7% respectively. This underscores a massive transformation driven by anthropogenic activities given rise to environmental issues in the Crocodile River catchment.

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“…In some countries, especially in arid and semi-arid areas, dependence on groundwater is very high. Groundwater with water supply capability during periods of drought is still the most reliable and stable source of water, especially in cases in which surface water supply is limited (Dube et al, 2020). Other bene ts of these vital resources include supporting a variety of socio-economic developments and maintaining a wide range of ecosystem functions and services (Mustapha et al, 2019;Shakerkhatibi et al, 2019).…”

Section: Introductionmentioning

confidence: 99%

“…In general, the groundwater system is controlled and affected by several complex interactions between different heterogeneous factors. The spatial and temporal variability approach can be effective in analyzing the current hydrochemical image of groundwater (Huang et al, 2018) In this regard, it is necessary to identify accurate and reliable methods to understand the spatial and temporal variability of groundwater quality Identifying potential toxins in groundwater is also essential to implement strategies to reduce the health risks associated with reducing groundwater quality, as well as identifying sources of water pollution (Dube et al, 2020). In recent years, with the increase in the number of physicochemical parameters of groundwater, a wide range of statistical methods are now used for proper analysis and interpretation of information.…”

Section: Introductionmentioning

confidence: 99%

Investigating spatial and temporal trend of groundwater quality in relation to water balance components (A case study of Chaharmahal va Bakhtiari Province, Iran)

Zamani‐Ahmadmahmoodi

Bayati

Abdollahi

et al. 2022

Preprint

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One of the problems of water resources in Iran is excessive drop in groundwater level, in which Chaharmahal va Bakhtiari province, located in this country, is no exception․ In this study, the trend of spatial and temporal changes in groundwater quality and water balance and the relationship between them in this province were investigated. The WetSpass-M distribution model was used due to the capability of distribution models in simulating watershed hydrological processes. The results showed good accuracy of the model in simulating runoff and basal flow of the study basin. The trend of water quality changes was investigated by calculating the IRWQI index and preparing its zoning maps. For this purpose, 132 samples of well water in different areas of the study were prepared in 2007 to 2017. Spatial distribution maps showed that the groundwater quality in the north and northeast of the region was lower than in other parts. Also, groundwater quality had declined over time. In rangeland, groundwater quality was better and nitrate level was lower than in agriculture and buildup land uses. Also, the relationship between nitrate and drought with water quality was seen due to the similar color pattern in their zoning maps in the region. The correlation between groundwater quality parameters and water balance components also showed a weak correlation on an annual scale and a strong correlation between some parameters in some wells on a monthly scale.

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Spatial modelling of groundwater quality across a land use and land cover gradient in Limpopo Province, South Africa

Cited by 19 publications

References 24 publications

Groundwater Quality Assessment in Aba (Abia State) Using WQI and GIS Techniques

Groundwater Quality Assessment in Aba (Abia State) Using WQI and GIS Techniques

An Assessment of Land Use and Land Cover Changes and Its Impact on the Surface Water Quality of the Crocodile River Catchment, South Africa

Investigating spatial and temporal trend of groundwater quality in relation to water balance components (A case study of Chaharmahal va Bakhtiari Province, Iran)

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