Environment and Ecology Research Vol. 11(1), pp. 42 - 64
DOI: 10.13189/eer.2023.110104
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Multivariate Analysis of the Dynamics in Water Quality and Trophic Status of the Crocodile River and Hartbeespoort Dam

Malebo D Matlala ^*
Department of Environmental Sciences, College of Agriculture and Environmental Sciences, University of South Africa, South Africa

ABSTRACT

Economic expansion coupled with population growth and associated anthropogenic activities are a threat to water resources globally. This study assessed the dynamics in water quality and trophic status of one of South Africa's hyper-eutrophic reservoirs, the Hartbeespoort Dam. Spatio-temporal variability in water quality parameters was determined on historical data spanning a period of forty years (1980-2020), with the aim of determining decadal changes in the Water Quality Index (WQI), the Water Pollution Index (WPI), the Canadian Council of Ministers of the Environment-Water Quality Index (CCME-WQI) as well as the Nutrient Pollution Index (NPI) and TN:TP ratios in the Hartbeespoort Dam as well as the Crocodile River. The calculated indices provide a single aggregated standardized score of water quality. The efficiency of a bioremediation programme (2007-2012) implemented as a mitigation measure to combat eutrophication in the dam was assessed. The study also investigated the impact of rainfall on the variability of the concentration and level of selected physico-chemical parameters. The results of the study revealed that apart from turbidity, rainfall has no significant impact on the variability of other water quality parameters studied. Furthermore, the WQI, CCME-WQI, WPI, as well as the NPI classified the general water quality of the dam as extremely poor and highly polluted. Moreover, TN:TP showed an increase in TP over time, further exacerbating hypereutrophic conditions in the catchment. The study also showed that the bioremediation programme was effective in reducing external P loading, however, bioturbation resulted in the resuspension of historical internal P loads, thus maintaining high phosphate concentrations at the site downstream from the Hartbeespoort Dam.

KEYWORDS
Bioremediation, Bioturbation, Eutrophication, NPI, Resuspension, Water Quality, Water Pollution

Cite This Paper in IEEE or APA Citation Styles
(a). IEEE Format:
[1] Malebo D Matlala , "Multivariate Analysis of the Dynamics in Water Quality and Trophic Status of the Crocodile River and Hartbeespoort Dam," Environment and Ecology Research, Vol. 11, No. 1, pp. 42 - 64, 2023. DOI: 10.13189/eer.2023.110104.

(b). APA Format:
Malebo D Matlala (2023). Multivariate Analysis of the Dynamics in Water Quality and Trophic Status of the Crocodile River and Hartbeespoort Dam. Environment and Ecology Research, 11(1), 42 - 64. DOI: 10.13189/eer.2023.110104.