Using Multiple Indices for the Water Resource Management of a Monomictic Man-Made Dam in Southern Africa

Abstract

This study employed different indices, namely the weighted arithmetic water quality index (WQI), Carlson Trophic State Index (TSI), van Ginkel TSI, and Trophic Level Index (TLI) to determine the water quality status of a man-made dam for the needs of sustainable water resource management in Southern Africa. The selection of indices for the study was based on the impacts of anthropogenic activities on the dam. The Roodeplaat Dam exhibited the spatial variation of physicochemical characteristics, indicative of influence by point-source pollution. Although the dam was classified as being eutro-hypertrophic, it was evident that water clarity was not a limiting factor but was P-limited, which was an indication of limiting conditions on primary production. Moreover, the WQI calculated for the dam with an average of 93.94 demonstrated very poor water quality that could be used for crop irrigation purposes only. As such, continued nutrient enrichment must be mitigated to sustain fitness for irrigation, at least. However, strategic goals should involve widening fitness for use. The selected indices were found to be effective for water resource management and could be applied to dams impacted by point-source pollution in Southern Africa. Thus, this study recommends the implementation of an integrated management approach, which needs to prioritize nutrient management to retain societal resource value.

Evaluation of River and Groundwater Quality in the Mzimvubu to Tsitsikamma Water Management Area (WMA7)

“…Sample bottles were turned slightly upward, and mouth was directed toward the water current. The bottles were filled to the top with as little air as possible and sealed tightly [13]. Further, every sample bottle contained particulars such as the name of the person who collected sample, date and time of collection, and description of place where samples were taken.…”

“…Further, samples were placed in cooler boxes filled with ice packs to maintain low temperatures, and sampling bailers were rinsed with de-ionised water. Both surface and groundwater samples were transported to the Resource Quality Information Services (RQIS) laboratory of the DWS, where they were stored under darkness at 4 • C until analysis [13].…”

“…In South Africa, Griffin et al [12] reported that the country is faced with a number of water quality challenges such as eutrophication, acid mine drainage (AMD) and anthropogenic salinisation. Eutrophication is a consequence of nutrient enrichment that leads to changes in ecology, such as algal bloom [12,13]. Further, eutrophication has the potential to impact ecological systems, human health, agriculture and recreation.…”

Estimation of Nutrient Load for Effective Water Resource Management in Dams: A case study of the Roodeplaat Dam, Southern Africa

“…The catchment area is 668 km 2 and the dam has a net capacity of 41.9 x 10 6 m 3 of which 50% is from the return ows from the Baviaanspoort and Zeekoegat Wastewater Treatment Works (WWTWs), a mean depth of 10.6 m, and a maximum depth of 43 m at the dam wall (Pieterse and Toerien 1978;van Ginkel and Silberbauer 2007). The water surface temperature of the dam from 2001-2021 averaged between 16 and 25 °C, which is an indication of a monomictic dam with stable thermal strati cation during the summer months (Mnyango et al 2022).…”

Research on the Sustainable Development of the Bistrita Ardeleana River in Order to Stop the Erosion of the Riverbanks and the Thalweg

“…71% of the Earth's surface is covered with water. The oceans (Atlantic, Arctic, Antarctic, Pacific, and Indian) represent 96.5% of Earth's water, 2.5% represents the total amount of fresh water, while the totality of the water in the hydrographic basins of the rivers represents 1% [1,2].…”