The refinement of protective salinity guidelines for South African freshwater resources
- Authors: Slaughter, Andrew Robert
- Date: 2005
- Subjects: Water salinization -- South Africa Salinization -- Control -- South Africa Salinity -- South Africa Freshwater ecology -- South Africa Water resources development -- South Africa Caridina Caridina -- Effect of pollution
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:6031 , http://hdl.handle.net/10962/d1006170
- Description: South Africa is an arid country and its growing population is putting freshwater resources under increasing pressure. Natural salinization of freshwater systems is being exacerbated by anthropogenic influences. The National Water Act (No. 36 of 1998) stipulates the need for an ecological Reserve, that quantity and quality of freshwater needed to protect freshwater ecosystems while allowing sustainable use of freshwater resources. Water guidelines do exist in the form of the South African Water Quality Guidelines (DWAF, 1996) and more recently, Jooste and Rossouw (2002) compiled benchmark values for water quality variables marking the boundaries between ecological health classes in the 4-category classification system. Predominantly international toxicity data were used to compile the guidelines and the benchmark values. In addition, there is a paucity of chronic toxicity data nationally and internationally. This thesis showed that it is statistically possible to derive protective chronic endpoints for salinity from acute toxicity data through extrapolation. The Acute to Chronic Ratio (ACR), Two-Step Linear Regression (LRA) and Multi-Factor Probit Analysis (MPA) extrapolation methods were investigated to derive chronic toxicity data from acute toxicity data. The authors of LRA and MPA recommend associating a time independent LCx value in the range of LC₀¸₀₁ to LC₁₀ with a Predicted No Effect Concentration (PNOEC). In addition to published methods, this thesis studied the possibility of equating a time independent LC₅₀ value and subjected to a safety factor of 5 (LRA LC₅₀/5), to the PNOEC. Extrapolated chronic toxicity data where the toxicants are NaCl and Na₂SO₄ were derived for indigenous South African macroinvertebrates. NaCl and Na₂SO₄ are salts associated with salinisation in South Africa. In addition, a chronic salinity toxicity test protocol for an indigenous South African aquatic macroinvertebrate was designed and chronic toxicity test were performed using NaCl and Na₂SO₄ as toxicants. The experimental chronic toxicity data produced were used to validate results from the acute to chronic extrapolation methods. Extrapolated chronic toxicity data were inputted into Species Sensitivity Distribution curves, and concentrations that were predicted to protect 95 % of species (PC95) were compared to the sub-lethality benchmarks proposed by Jooste and Rossouw (2002) for NaCl and Na₂SO₄. This study concluded that the LRA LC₅₀/5 extrapolation method is the most protective and accurate and proposed that LRA replace the ACR method in future guideline development for inorganic salts.
- Full Text:
- Authors: Slaughter, Andrew Robert
- Date: 2005
- Subjects: Water salinization -- South Africa Salinization -- Control -- South Africa Salinity -- South Africa Freshwater ecology -- South Africa Water resources development -- South Africa Caridina Caridina -- Effect of pollution
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:6031 , http://hdl.handle.net/10962/d1006170
- Description: South Africa is an arid country and its growing population is putting freshwater resources under increasing pressure. Natural salinization of freshwater systems is being exacerbated by anthropogenic influences. The National Water Act (No. 36 of 1998) stipulates the need for an ecological Reserve, that quantity and quality of freshwater needed to protect freshwater ecosystems while allowing sustainable use of freshwater resources. Water guidelines do exist in the form of the South African Water Quality Guidelines (DWAF, 1996) and more recently, Jooste and Rossouw (2002) compiled benchmark values for water quality variables marking the boundaries between ecological health classes in the 4-category classification system. Predominantly international toxicity data were used to compile the guidelines and the benchmark values. In addition, there is a paucity of chronic toxicity data nationally and internationally. This thesis showed that it is statistically possible to derive protective chronic endpoints for salinity from acute toxicity data through extrapolation. The Acute to Chronic Ratio (ACR), Two-Step Linear Regression (LRA) and Multi-Factor Probit Analysis (MPA) extrapolation methods were investigated to derive chronic toxicity data from acute toxicity data. The authors of LRA and MPA recommend associating a time independent LCx value in the range of LC₀¸₀₁ to LC₁₀ with a Predicted No Effect Concentration (PNOEC). In addition to published methods, this thesis studied the possibility of equating a time independent LC₅₀ value and subjected to a safety factor of 5 (LRA LC₅₀/5), to the PNOEC. Extrapolated chronic toxicity data where the toxicants are NaCl and Na₂SO₄ were derived for indigenous South African macroinvertebrates. NaCl and Na₂SO₄ are salts associated with salinisation in South Africa. In addition, a chronic salinity toxicity test protocol for an indigenous South African aquatic macroinvertebrate was designed and chronic toxicity test were performed using NaCl and Na₂SO₄ as toxicants. The experimental chronic toxicity data produced were used to validate results from the acute to chronic extrapolation methods. Extrapolated chronic toxicity data were inputted into Species Sensitivity Distribution curves, and concentrations that were predicted to protect 95 % of species (PC95) were compared to the sub-lethality benchmarks proposed by Jooste and Rossouw (2002) for NaCl and Na₂SO₄. This study concluded that the LRA LC₅₀/5 extrapolation method is the most protective and accurate and proposed that LRA replace the ACR method in future guideline development for inorganic salts.
- Full Text:
Using aspects of game theory for enhanced stakeholder participation perspectives in integrated water resource management: a Kat River Valley case study
- Authors: Mbatha, Cyril
- Date: 2005
- Subjects: Water resources development -- Case studies , Water-supply -- South Africa -- Kat River Valley -- Management , Economic development -- Case studies , Water-supply -- Government policy -- South Africa , Economic development -- South Africa -- Kat River Valley , Game theory
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:971 , http://hdl.handle.net/10962/d1002705 , Water resources development -- Case studies , Water-supply -- South Africa -- Kat River Valley -- Management , Economic development -- Case studies , Water-supply -- Government policy -- South Africa , Economic development -- South Africa -- Kat River Valley , Game theory
- Description: South Africa is a water poor region and yet, like in many other developing countries, water resources are a valuable production input in socially important industries such as agriculture and mining (Nieuwoudt et al., 2004:162-182). With a mean annual rainfall and runoff of 502mm and 42mm (420m³ per hectare per annum) respectively, Briers and Powell (1993:1) speculate that water shortages will limit South Africa’s economic development in the twenty-first century. In response to the challenges of water resource scarcity and socio-economic inequalities, in 1997 the South African Department of Water Affairs and Forestry (DWAF), following international trends, formulated a National Water Policy (NWP) based on Integrated Water Resource Management (IWRM) principles (Palmer et al., 2003). The main objectives of the NWP (1997) are to protect national water resources from degradation, provide economically disadvantaged communities with access to water resources and promote economic development, through the devolution of water management responsibilities to locally established water institutions (NWP, 1997). The pursuit of these objectives requires a thorough investigation of biophysical, sociopolitical and economic characteristics of the demarcated water areas. For such an investigation to provide accurate and locally relevant results, broad stakeholder participation is of paramount importance. The thesis discusses economic measures required in pursuing enhanced stakeholder participation levels at local levels. A socio-economic survey investigation describing major participation trends against reported property rights and Willingness to Pay values was conducted in the Kat River Valley, Eastern Cape province. From the investigation, observed participation trends driven by economic interests were identified and used in recommendations proposed for the policy implementation process. Using game theoretic arguments as guidelines in soliciting cooperative behaviour in the use and consumption of common resources (Ostrom, 1990), the thesis proposes the introduction of water related public works projects as employment creating vehicles for individuals and communities targeted for economic empowerment and participation in the water policy. However, for sustainable stakeholder participation levels, it is argued that the employment positions created through the projects need to be designed in a manner that would encourage an evolution of long-term relationships between stakeholders and the water management institutions.
- Full Text:
- Authors: Mbatha, Cyril
- Date: 2005
- Subjects: Water resources development -- Case studies , Water-supply -- South Africa -- Kat River Valley -- Management , Economic development -- Case studies , Water-supply -- Government policy -- South Africa , Economic development -- South Africa -- Kat River Valley , Game theory
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:971 , http://hdl.handle.net/10962/d1002705 , Water resources development -- Case studies , Water-supply -- South Africa -- Kat River Valley -- Management , Economic development -- Case studies , Water-supply -- Government policy -- South Africa , Economic development -- South Africa -- Kat River Valley , Game theory
- Description: South Africa is a water poor region and yet, like in many other developing countries, water resources are a valuable production input in socially important industries such as agriculture and mining (Nieuwoudt et al., 2004:162-182). With a mean annual rainfall and runoff of 502mm and 42mm (420m³ per hectare per annum) respectively, Briers and Powell (1993:1) speculate that water shortages will limit South Africa’s economic development in the twenty-first century. In response to the challenges of water resource scarcity and socio-economic inequalities, in 1997 the South African Department of Water Affairs and Forestry (DWAF), following international trends, formulated a National Water Policy (NWP) based on Integrated Water Resource Management (IWRM) principles (Palmer et al., 2003). The main objectives of the NWP (1997) are to protect national water resources from degradation, provide economically disadvantaged communities with access to water resources and promote economic development, through the devolution of water management responsibilities to locally established water institutions (NWP, 1997). The pursuit of these objectives requires a thorough investigation of biophysical, sociopolitical and economic characteristics of the demarcated water areas. For such an investigation to provide accurate and locally relevant results, broad stakeholder participation is of paramount importance. The thesis discusses economic measures required in pursuing enhanced stakeholder participation levels at local levels. A socio-economic survey investigation describing major participation trends against reported property rights and Willingness to Pay values was conducted in the Kat River Valley, Eastern Cape province. From the investigation, observed participation trends driven by economic interests were identified and used in recommendations proposed for the policy implementation process. Using game theoretic arguments as guidelines in soliciting cooperative behaviour in the use and consumption of common resources (Ostrom, 1990), the thesis proposes the introduction of water related public works projects as employment creating vehicles for individuals and communities targeted for economic empowerment and participation in the water policy. However, for sustainable stakeholder participation levels, it is argued that the employment positions created through the projects need to be designed in a manner that would encourage an evolution of long-term relationships between stakeholders and the water management institutions.
- Full Text:
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