- Title
- Ecological impacts of small dams on South African rivers Part 1: Drivers of change–water quantity and quality
- Creator
- Mantel, Sukhmani K, Hughes, Denis A, Muller, Nikite W J
- Subject
- To be catalogued
- Date
- 2010
- Type
- text
- Type
- report
- Identifier
- http://hdl.handle.net/10962/438099
- Identifier
- vital:73435
- Identifier
- ISBN 1816-7950
- Identifier
- https://wrcwebsite.azurewebsites.net/wp-content/uploads/mdocs/2398.pdf
- Description
- Impacts of large dams are well-known and quantifiable, while small dams have generally been perceived as benign, both socially and envi-ronmentally. The present study quantifies the cumulative impacts of small dams on the water quality (physico-chemistry and invertebrate biotic indices) and quantity (discharge) of downstream rivers in 2 South African regions. The information from 2 South African national data-bases was used for evaluating the cumulative impacts on water quality and quantity. Physico-chemistry and biological data were obtained from the River Health Programme, and discharge data at stream flow gauges was obtained from the Hydrological Information System. Multivariate analyses were conducted to establish broad patterns for cumulative impacts of small dams across the 2 regions–Western Cape (winter rain-fall, temperate, south-western coast) and Mpumalanga (summer rain-fall, tropical, eastern coast). Multivariate analyses found that the chang-es in macroinvertebrate indices and the stream’s physico-chemistry were more strongly correlated with the density of small dams in the catchment (as a measure of cumulative impact potential) relative to the storage capacity of large dams. T-tests on the data, not including sam-ples with upstream large dams, indicated that the high density of small dams significantly reduced low flows and increased certain physico-chemistry variables (particularly total dissolved salts) in both the re-gions, along with associated significant reductions in a macroinverte-brate index (SASS4 average score per taxon). Regional differences were apparent in the results for discharge reductions and the macroin-vertebrate index. The results suggest that the cumulative effect of a high number of small dams is impacting the quality and quantity of wa-ters in South African rivers and that these impacts need to be systemat-ically incorporated into the monitoring protocol of the environmental wa-ter requirements.
- Format
- 10 pages, pdf
- Publisher
- Water Research Commission
- Language
- English
- Relation
- Mantel, S.K., Hughes, D.A. and Muller, N.W., 2010. Ecological impacts of small dams on South African rivers Part 1: Drivers of change–water quantity and quality. Water Sa, 36(3), pp.351-360
- Rights
- Publisher
- Rights
- Use of this resource is governed by the terms and conditions of the Water Research Commission Terms and Conditions of Use Statement (https://www.gov.za/terms-and-conditions-use-0)
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Hughes, Denis Arthur (Prof)
Muller, Nikite Wilhelmine Josephine (Dr)
Mantel, Sukhmani Kaur (Dr)
RU Institute for Water Research, including the Unilever Centre for Environmental Water Quality (IWR)
SDG 06. Clean Water and Sanitation
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| Thumbnail | File | Description | Size | Format | |||
|---|---|---|---|---|---|---|---|
| View Details | SOURCE1 | Ecological impacts of small dams on South African rivers (3).pdf | 562 KB | Adobe Acrobat PDF | View Details |