The Limnology of Some South African Impoundments I. The Physico-Chemical Limnology of Hartbeespoort Dam

Scott, William E.; Seaman, Maitland; Connell, Allan D.; Kohlmeyer, S. I.; Toerien, D.F.

doi:10.1080/03779688.1977.9633135

Cited by 15 publications

(11 citation statements)

References 8 publications

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“…However, k estimates have been made for certain impoundments (Table 2). For these impoundments the minimum value recorded was for the Hartbeespoort Dam (0,36 m -1 - Scott et al, 1977) whilst the maximum …”

Section: Attenuation Coefficitntmentioning

confidence: 99%

Water Transparency Characteristics of South African Impoundments

Walmsley

Bruwer

1980

Journal of the Limnological Society of Southern Africa

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Some water transparency characteristics (Secchi disc transparency, mean diffuse light attenuation coefficient and turbidity) of a nu~ber of South African impoundments are compared. In general most impoundments may be considered to be highly turbid; for 92 impoundments considered in this paper the modal mean Secchi disc transparency was in the class 0 to 0,5 m. The geographical distribution of water transparency within South Africa shows good agreement with the geographical distribution of sediment production, indicating that suspended inorganic material is the dominant factor governing water transparency in most impoundments. There is evidence that eutrophication and mineralization are processes which lead to increased water transparency. High turbidity and its role in influencing the limnology and management of impoundments is discussed. More in-depth investigations are needed to evaluate the contributions by coloured substances, suspended silt and phytoplankton to light attenuation within individual impoundments.

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Section: Attenuation Coefficitntmentioning

confidence: 99%

Water Transparency Characteristics of South African Impoundments

Walmsley

Bruwer

1980

Journal of the Limnological Society of Southern Africa

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“…Detailed information on the limnology and phytoplankton dynamics of Hartbeespoort is available (e.g., [15][16][17]). It is one of the most productive reservoirs in the world, with so-called hyperscums of Microcystis Aeruginosa [18].…”

Section: Study Areas and Sampling Strategymentioning

confidence: 99%

Characterizing the Absorption Properties for Remote Sensing of Three Small Optically-Diverse South African Reservoirs

Matthews

Bernard

2013

Remote Sensing

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Characterizing the specific inherent optical properties (SIOPs) of water constituents is fundamental to remote sensing applications.Therefore, this paper presents the absorption properties of phytoplankton, gelbstoff and tripton for three small, optically-diverse South African inland waters. The three reservoirs, Hartbeespoort, Loskop and Theewaterskloof, are challenging for remote sensing, due to differences in phytoplankton assemblage and the considerable range of constituent concentrations. Relationships between the absorption properties and biogeophysical parameters, chlorophyll-a (chl-a), TChl (chl-a plus phaeopigments), seston, minerals and tripton, are established. The value determined for the mass-specific tripton absorption coefficient at 442 nm, a * tr (442), ranges from 0.024 to 0.263 m 2 ·g −1 . The value of the TChl-specific phytoplankton absorption coefficient (a * φ ) was strongly influenced by phytoplankton species, size, accessory pigmentation and biomass. a * φ (440) ranged from 0.056 to 0.018 m 2 ·mg −1 in oligotrophic to hypertrophic waters. The positive relationship between cell size and trophic state observed in open ocean waters was violated by significant small cyanobacterial populations. The phycocyanin-specific phytoplankton absorption at 620 nm, a * pc (620), was determined as 0.007 m 2 ·g −1 in a M. aeruginosa bloom. Chl-a was a better indicator of phytoplankton biomass than phycocyanin (PC) in surface scums, due to reduced accessory pigment production. Absorption budgets demonstrate that monospecific blooms of M. aeruginosa and C. hirundinella may be treated as "cultures", removing some complexities for remote sensing applications. These results contribute toward a better Remote Sens. 2013, 5 4371 understanding of IOPs and remote sensing applications in hypertrophic inland waters. However, the majority of the water is optically complex, requiring the usage of all the SIOPs derived here for remote sensing applications. The SIOPs may be used for developing remote sensing algorithms for the detection of biogeophysical parameters, including chl-a, suspended matter, tripton and gelbstoff, and in advanced remote sensing studies for phytoplankton type detection.

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“…Outstanding amongst the few reservoir papers is a comprehensive assessment on Hartbeespoort Damwhich concluded that conditions were rapidly worsening and that "sound and firm remedial action is necessary" (Scott et al, 1977). Roodeplaat Dam, the other 'ugly sister' of enriched South African reservoirs (see Figure 1), was classified as a "highly eutrophic waterbody" by Walmsley et al (1978).…”

Section: A History Of Lake Management Science In South Africamentioning

confidence: 99%

Living with eutrophication in South Africa: a review of realities and challenges

Harding¹

2015

Transactions of the Royal Society of South Africa

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The socio-economic well-being of South Africa is largely dependent on reservoir lakes. Contrastingly, the country lacks reservoir management skills and training, with a generation having passed since there was limited activity in this field. This review introduces two new, independent analyses which, using in-lake total phosphorus or satellite-measured chlorophyll-a, respectively, reveal that between 41% and 76% of total storage is eutrophic or hypertrophic. This is in stark contrast to a claimed 5% made by the responsible government agency (Department of Water and Sanitation). Data and information on the incidence and toxicity of cyanobacterial blooms are sparse, yet severe problems exist. There is a concentration of focus on water quantity, with absent parallel consideration of the additional limitations posed by poor water quality. The most seriously impacted reservoirs are located in the economic heartland of South Africa, which has an extant regional water quality crisis. The reasons behind the startling lack of attention to reservoir limnology, despite clear and long-standing warnings, are examined and placed in the perspective of an acknowledged and impending water crisis. It will take considerable time to up-skill South African limnologists to meet the needs highlighted by worsening reservoir water quality, and to offset the social and economic impacts that will transpire, if not timeously ameliorated. The responsible agency urgently needs to establish a reservoir-management programme that embraces remaining individual and institutional memory, integrates all available relevant knowledge and scientific findings, prioritises needs and acquires those skills and resources necessary to meet what is likely to become a crippling legacy of inaction.

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The Limnology of Some South African Impoundments I. The Physico-Chemical Limnology of Hartbeespoort Dam

Cited by 15 publications

References 8 publications

Water Transparency Characteristics of South African Impoundments

Water Transparency Characteristics of South African Impoundments

Characterizing the Absorption Properties for Remote Sensing of Three Small Optically-Diverse South African Reservoirs

Living with eutrophication in South Africa: a review of realities and challenges

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