Towards The Quantification Of The Historical And Future Water Resources Of The Limpopo River
- Kapangaziwiri, Evison, Kahinda, Jean-Marc M, Oosthuizen, Nadia, Mvandaba, Vuyelwa, Hobbs, Philip, Hughes, Denis A
- Authors: Kapangaziwiri, Evison , Kahinda, Jean-Marc M , Oosthuizen, Nadia , Mvandaba, Vuyelwa , Hobbs, Philip , Hughes, Denis A
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , report
- Identifier: http://hdl.handle.net/10962/438349 , vital:73453 , ISBN 978-0-6392-0303-4 , https://wrcwebsite.azurewebsites.net/wp-content/uploads/mdocs/2439_final.pdf
- Description: The complexity of current water resource management poses many challenges. Wa-ter managers must solve a range of interrelated dilemmas – such as balancing quan-tity and quality, mitigating the effects of flooding and drought, and maintaining bio-diversity, ecological functions, and services. Sustainable water resource manage-ment, planning, and development requires reliable quantification of the amount, distribution, and quality of water within river basins. With the demand for water resources rapidly growing across the globe, there is also an urgent need for accu-rate monitoring, forecasting and simulation of hydrologic variables – especially in major (often transboundary) river basins such as the Limpopo – not only for optimal water resources management but more compellingly, also for water security, food security, power generation, and economic development. However, the available data are frequently far from sufficient – in terms of availability, accuracy, and spa-tial/temporal resolution – for the understanding of both natural and anthropogenic processes (and their complex linkages) in a river basin. Such challenges also make it very difficult to use the data for the practical application of estimation of water resources availability.
- Full Text:
- Date Issued: 2021
- Authors: Kapangaziwiri, Evison , Kahinda, Jean-Marc M , Oosthuizen, Nadia , Mvandaba, Vuyelwa , Hobbs, Philip , Hughes, Denis A
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , report
- Identifier: http://hdl.handle.net/10962/438349 , vital:73453 , ISBN 978-0-6392-0303-4 , https://wrcwebsite.azurewebsites.net/wp-content/uploads/mdocs/2439_final.pdf
- Description: The complexity of current water resource management poses many challenges. Wa-ter managers must solve a range of interrelated dilemmas – such as balancing quan-tity and quality, mitigating the effects of flooding and drought, and maintaining bio-diversity, ecological functions, and services. Sustainable water resource manage-ment, planning, and development requires reliable quantification of the amount, distribution, and quality of water within river basins. With the demand for water resources rapidly growing across the globe, there is also an urgent need for accu-rate monitoring, forecasting and simulation of hydrologic variables – especially in major (often transboundary) river basins such as the Limpopo – not only for optimal water resources management but more compellingly, also for water security, food security, power generation, and economic development. However, the available data are frequently far from sufficient – in terms of availability, accuracy, and spa-tial/temporal resolution – for the understanding of both natural and anthropogenic processes (and their complex linkages) in a river basin. Such challenges also make it very difficult to use the data for the practical application of estimation of water resources availability.
- Full Text:
- Date Issued: 2021
Impacts of Climate Change in Determining the Ecological Reserve
- Tanner, Jane L, Griffin, Neil J, Slaughter, Andrew R, Mantel, Sukhmani K, Dabula, Pumza, Hughes, Denis A, Wolff, Margaret G
- Authors: Tanner, Jane L , Griffin, Neil J , Slaughter, Andrew R , Mantel, Sukhmani K , Dabula, Pumza , Hughes, Denis A , Wolff, Margaret G
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , report
- Identifier: http://hdl.handle.net/10962/438128 , vital:73437 , ISBN 978-0-6392-0124-5 , https://wrcwebsite.azurewebsites.net/wp-content/uploads/mdocs/2834 final.pdf
- Description: The intermediate and long-term impacts of climate change require evaluation of the adaptive capacity of the riverine ecosystems to pro-mote sustainability. The predicted climate change impacts are the moti-vation behind the current research which targets the knowledge gap of the impacts of climate change on the ecological Reserve (or Ecological Water Requirements [EWR]). In order for the Department of Water and Sanitation (DWS) to meet their mandate to protect aquatic ecosystems, given the constraints of climate change, it is necessary to take cogni-sance of the implications of climate change and to make the necessary adjustments and changes to the ecological Reserve determination methodology. These adjustments will help ensure that sufficient water, at the right time, distributed in the right flow pattern and of adequate quality is provided, so that key ecological processes are sustained, and that biotic communities maintain their health and integrity.
- Full Text:
- Date Issued: 2020
- Authors: Tanner, Jane L , Griffin, Neil J , Slaughter, Andrew R , Mantel, Sukhmani K , Dabula, Pumza , Hughes, Denis A , Wolff, Margaret G
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , report
- Identifier: http://hdl.handle.net/10962/438128 , vital:73437 , ISBN 978-0-6392-0124-5 , https://wrcwebsite.azurewebsites.net/wp-content/uploads/mdocs/2834 final.pdf
- Description: The intermediate and long-term impacts of climate change require evaluation of the adaptive capacity of the riverine ecosystems to pro-mote sustainability. The predicted climate change impacts are the moti-vation behind the current research which targets the knowledge gap of the impacts of climate change on the ecological Reserve (or Ecological Water Requirements [EWR]). In order for the Department of Water and Sanitation (DWS) to meet their mandate to protect aquatic ecosystems, given the constraints of climate change, it is necessary to take cogni-sance of the implications of climate change and to make the necessary adjustments and changes to the ecological Reserve determination methodology. These adjustments will help ensure that sufficient water, at the right time, distributed in the right flow pattern and of adequate quality is provided, so that key ecological processes are sustained, and that biotic communities maintain their health and integrity.
- Full Text:
- Date Issued: 2020
Extending functionality and knowledge transfer of the Water Quality Systems Assessment Model
- Slaughter, Andrew R, Gwapedza, David, Mantel, Sukhmani K, Hughes, Denis A, Griffin, Neil J
- Authors: Slaughter, Andrew R , Gwapedza, David , Mantel, Sukhmani K , Hughes, Denis A , Griffin, Neil J
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , report
- Identifier: http://hdl.handle.net/10962/438115 , vital:73436 , ISBN 978-0-6392-0059-0 , https://wrcwebsite.azurewebsites.net/wp-content/uploads/mdocs/2448_final.pdf
- Description: This report has been generated by the Water Research Commission (WRC) funded project Developing Climate Change Adaptation Measures and Decision-Support System for Selected South African Water Boards (Project No. K5/2018).
- Full Text:
- Date Issued: 2018
- Authors: Slaughter, Andrew R , Gwapedza, David , Mantel, Sukhmani K , Hughes, Denis A , Griffin, Neil J
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , report
- Identifier: http://hdl.handle.net/10962/438115 , vital:73436 , ISBN 978-0-6392-0059-0 , https://wrcwebsite.azurewebsites.net/wp-content/uploads/mdocs/2448_final.pdf
- Description: This report has been generated by the Water Research Commission (WRC) funded project Developing Climate Change Adaptation Measures and Decision-Support System for Selected South African Water Boards (Project No. K5/2018).
- Full Text:
- Date Issued: 2018
Implementing uncertainty analysis in water resources assessment and planning
- Hughes, Denis A, Mohobane, T, Mallory, S
- Authors: Hughes, Denis A , Mohobane, T , Mallory, S
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , report
- Identifier: http://hdl.handle.net/10962/438281 , vital:73448 , ISBN 978-1-4312-0629-2 , https://wrcwebsite.azurewebsites.net/wp-content/uploads/mdocs/2056-1-14.pdf
- Description: The main objective of the project was to contribute to the incorporation of uncer-tainty assessments in practical water resource decision-making in South Africa. There are three main components to this objective. The first is the quantification of realistic levels of uncertainty that are as low as possible given the available infor-mation (reducing uncertainty). The second is the availability of tools to implement uncertainty analysis across the broad spectrum of data analysis and modelling plat-forms that form part of practical water resources assessment (including hydrologi-cal and water resources yield models). The third relates to the issue of using uncer-tain information in the process of making decisions about the design, development or operation of water resources systems. The latter includes social, political and economic uncertainties as well as the hydrological uncertainties that are directly addressed in this report. None of these are independent and all are associated with the fundamental issue that all of the role players should understand the key con-cepts of uncertainty and that virtually all of the information we use to make deci-sions is uncertain. One of the major challenges in this project as well as the previous WRC-supported project on uncertainty methods, was the lack of understanding of some of the key issues, or a lack of appreciation of the importance of uncertainty in all water resources decision-making.
- Full Text:
- Date Issued: 2015
- Authors: Hughes, Denis A , Mohobane, T , Mallory, S
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , report
- Identifier: http://hdl.handle.net/10962/438281 , vital:73448 , ISBN 978-1-4312-0629-2 , https://wrcwebsite.azurewebsites.net/wp-content/uploads/mdocs/2056-1-14.pdf
- Description: The main objective of the project was to contribute to the incorporation of uncer-tainty assessments in practical water resource decision-making in South Africa. There are three main components to this objective. The first is the quantification of realistic levels of uncertainty that are as low as possible given the available infor-mation (reducing uncertainty). The second is the availability of tools to implement uncertainty analysis across the broad spectrum of data analysis and modelling plat-forms that form part of practical water resources assessment (including hydrologi-cal and water resources yield models). The third relates to the issue of using uncer-tain information in the process of making decisions about the design, development or operation of water resources systems. The latter includes social, political and economic uncertainties as well as the hydrological uncertainties that are directly addressed in this report. None of these are independent and all are associated with the fundamental issue that all of the role players should understand the key con-cepts of uncertainty and that virtually all of the information we use to make deci-sions is uncertain. One of the major challenges in this project as well as the previous WRC-supported project on uncertainty methods, was the lack of understanding of some of the key issues, or a lack of appreciation of the importance of uncertainty in all water resources decision-making.
- Full Text:
- Date Issued: 2015
Understanding and modelling surface water-groundwater interactions
- Tanner, Jane L, Hughes, Denis A
- Authors: Tanner, Jane L , Hughes, Denis A
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , report
- Identifier: http://hdl.handle.net/10962/438220 , vital:73444 , ISBN 978-1-4312-0630-8 , https://wrcwebsite.azurewebsites.net/wp-content/uploads/mdocs/2056%20-2-14.pdf
- Description: The main objective of the total project was to contribute to the incorpo-ration of uncertainty assessments in practical water resource decision making in South Africa. The companion report addresses more general issues of uncertainty and hydrological modelling, while this report con-centrates on the uncertainties in both understanding and modelling the interactions between surface water and groundwater. Since groundwa-ter routines were added into the widely used Pitman model in the early 2000s by both Prof Hughes and Mr Karim Sami, the approaches have come under a great deal of criticism mainly from the geohydrological community of specialists within South Africa. Arguably, a great deal of this criticism is based on misunderstandings of the intention of adding groundwater routines into an existing surface water model. It was stated quite clearly at the time that this approach was not seen as a replace-ment for existing detailed numerical approaches to groundwater model-ling. The intention was to create a scientific and practical tool that could be used to simulate the complete hydrological cycle at the catchment scale so that integrated water resources decision making could be better supported.
- Full Text:
- Date Issued: 2015
- Authors: Tanner, Jane L , Hughes, Denis A
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , report
- Identifier: http://hdl.handle.net/10962/438220 , vital:73444 , ISBN 978-1-4312-0630-8 , https://wrcwebsite.azurewebsites.net/wp-content/uploads/mdocs/2056%20-2-14.pdf
- Description: The main objective of the total project was to contribute to the incorpo-ration of uncertainty assessments in practical water resource decision making in South Africa. The companion report addresses more general issues of uncertainty and hydrological modelling, while this report con-centrates on the uncertainties in both understanding and modelling the interactions between surface water and groundwater. Since groundwa-ter routines were added into the widely used Pitman model in the early 2000s by both Prof Hughes and Mr Karim Sami, the approaches have come under a great deal of criticism mainly from the geohydrological community of specialists within South Africa. Arguably, a great deal of this criticism is based on misunderstandings of the intention of adding groundwater routines into an existing surface water model. It was stated quite clearly at the time that this approach was not seen as a replace-ment for existing detailed numerical approaches to groundwater model-ling. The intention was to create a scientific and practical tool that could be used to simulate the complete hydrological cycle at the catchment scale so that integrated water resources decision making could be better supported.
- Full Text:
- Date Issued: 2015
Informing the Responses of Water Service Delivery Institutions to Climate and Development Changes: A Case Study in the Amatole Region, Eastern Cape
- Hughes, Denis A, Mantel, Sukhmani K, Slaughter, Andrew R
- Authors: Hughes, Denis A , Mantel, Sukhmani K , Slaughter, Andrew R
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , report
- Identifier: http://hdl.handle.net/10962/438140 , vital:73438 , ISBN 978-1-4312-0520-2 , https://wrcwebsite.azurewebsites.net/wp-content/uploads/mdocs/2018-1-14.pdf
- Description: This report has been generated by the Water Research Commission (WRC) funded project Developing Climate Change Adaptation Measures and Decision-Support System for Selected South African Water Boards (Project No. K5/2018).
- Full Text:
- Date Issued: 2014
- Authors: Hughes, Denis A , Mantel, Sukhmani K , Slaughter, Andrew R
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , report
- Identifier: http://hdl.handle.net/10962/438140 , vital:73438 , ISBN 978-1-4312-0520-2 , https://wrcwebsite.azurewebsites.net/wp-content/uploads/mdocs/2018-1-14.pdf
- Description: This report has been generated by the Water Research Commission (WRC) funded project Developing Climate Change Adaptation Measures and Decision-Support System for Selected South African Water Boards (Project No. K5/2018).
- Full Text:
- Date Issued: 2014
ECOMAG Model: an evaluation for use in South Africa
- Mokoena, M P, Kapangaziwiri, E, Kahinda, J M, Hughes, Denis A
- Authors: Mokoena, M P , Kapangaziwiri, E , Kahinda, J M , Hughes, Denis A
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , report
- Identifier: http://hdl.handle.net/10962/438268 , vital:73447 , ISBN 978-1-4312-0408-3 , https://wrcwebsite.azurewebsites.net/wp-content/uploads/mdocs/TT%20555-13.pdf
- Description: The complexity of current approaches to water resource management poses many challenges. Water managers need to solve a range of interrelated water dilemmas, such as balancing water quantity and quality, flooding, drought, maintaining biodi-versity and ecological functions and the supply of water services to people. It is a sad fact in southern Africa that water availability is highly variable both spatially and temporally with low runoff coefficients of less than 9% conversion of mean annual precipitation (MAP) to mean annual runoff (MAR) known to be prevalent across large parts of the region (FAO, 2003). With predictions of water scarcity conditions, caused by rapid population growth, expanding urbanisation, increased economic development and climate change, (Rosegrant and Perez, 1997), water looks set to become a limiting resource in Southern Africa. The dynamics of demand and supply will have a large impact on the future socio-economic development of the region (Basson et al., 1997).
- Full Text:
- Date Issued: 2013
- Authors: Mokoena, M P , Kapangaziwiri, E , Kahinda, J M , Hughes, Denis A
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , report
- Identifier: http://hdl.handle.net/10962/438268 , vital:73447 , ISBN 978-1-4312-0408-3 , https://wrcwebsite.azurewebsites.net/wp-content/uploads/mdocs/TT%20555-13.pdf
- Description: The complexity of current approaches to water resource management poses many challenges. Water managers need to solve a range of interrelated water dilemmas, such as balancing water quantity and quality, flooding, drought, maintaining biodi-versity and ecological functions and the supply of water services to people. It is a sad fact in southern Africa that water availability is highly variable both spatially and temporally with low runoff coefficients of less than 9% conversion of mean annual precipitation (MAP) to mean annual runoff (MAR) known to be prevalent across large parts of the region (FAO, 2003). With predictions of water scarcity conditions, caused by rapid population growth, expanding urbanisation, increased economic development and climate change, (Rosegrant and Perez, 1997), water looks set to become a limiting resource in Southern Africa. The dynamics of demand and supply will have a large impact on the future socio-economic development of the region (Basson et al., 1997).
- Full Text:
- Date Issued: 2013
Deployment, Maintenance And Further Development Of Spatsim-HDSF Volume
- Clark, D J, Hughes, Denis A, Smithers, J C, Thornton-Dibb, S L C, Forsyth, David A
- Authors: Clark, D J , Hughes, Denis A , Smithers, J C , Thornton-Dibb, S L C , Forsyth, David A
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , report
- Identifier: http://hdl.handle.net/10962/438323 , vital:73451 , ISBN 978-1-4312-0295-9 , https://wrcwebsite.azurewebsites.net/wp-content/uploads/mdocs/1870-1-121.pdf
- Description: The National Water Act (NWA, 1998) of South Africa (Act 36 of 1998) aims to ensure that South Africa’s water resources are managed and used in an equitable and sus-tainable manner for the benefit of all. The National Water Act (NWA) requires a dif-ferent approach to managing the nation’s water resources and the concept of inte-grated water resources management (IWRM) is central to this approach (Pollard and Du Toit, 2008). IWRM requires water managers to consider hydrological, ecological, economic, political, social and institutional aspects of water resources. To imple-ment IWRM, water managers require integrated modelling tools to provide infor-mation that can assist in making managements decisions. There are two aspects of integrated modelling that have received increasing attention in recent years: (i) the coupling of models representing different water resource domains, and (ii) the de-velopment of integrated modelling frameworks or decision support systems. These integrated modelling frameworks typically include a common data repository, common data editing tools, common spatial and temporal data visualisation and analysis tools, and a collection of framework compatible models that make use of these common tools.
- Full Text:
- Date Issued: 2012
- Authors: Clark, D J , Hughes, Denis A , Smithers, J C , Thornton-Dibb, S L C , Forsyth, David A
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , report
- Identifier: http://hdl.handle.net/10962/438323 , vital:73451 , ISBN 978-1-4312-0295-9 , https://wrcwebsite.azurewebsites.net/wp-content/uploads/mdocs/1870-1-121.pdf
- Description: The National Water Act (NWA, 1998) of South Africa (Act 36 of 1998) aims to ensure that South Africa’s water resources are managed and used in an equitable and sus-tainable manner for the benefit of all. The National Water Act (NWA) requires a dif-ferent approach to managing the nation’s water resources and the concept of inte-grated water resources management (IWRM) is central to this approach (Pollard and Du Toit, 2008). IWRM requires water managers to consider hydrological, ecological, economic, political, social and institutional aspects of water resources. To imple-ment IWRM, water managers require integrated modelling tools to provide infor-mation that can assist in making managements decisions. There are two aspects of integrated modelling that have received increasing attention in recent years: (i) the coupling of models representing different water resource domains, and (ii) the de-velopment of integrated modelling frameworks or decision support systems. These integrated modelling frameworks typically include a common data repository, common data editing tools, common spatial and temporal data visualisation and analysis tools, and a collection of framework compatible models that make use of these common tools.
- Full Text:
- Date Issued: 2012
Deployment, Maintenance And Further Development Of Spatsim-HDSF: Volume 2
- Hughes, Denis A, Forsyth, David A, Stassen, J J M, van Niekerk, E
- Authors: Hughes, Denis A , Forsyth, David A , Stassen, J J M , van Niekerk, E
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , report
- Identifier: http://hdl.handle.net/10962/438255 , vital:73446 , ISBN 978-1-4312-0296-6 , https://wrcwebsite.azurewebsites.net/wp-content/uploads/mdocs/1870%20-2-121.pdf
- Description: The purpose of the National Database is to create a central repository of Reserve or EWR determination results that can be accessed by DWA as well as their service providers to ensure that information is not lost and that the maximum benefit is gained from previous experience for future determinations. This document summa-rises the information content of the database, as well as providing guidelines for entering new data and using existing data. Reference to both Reserve and EWR de-terminations is used as some of the data that are included pre-date the official con-cept of the ecological ‘Reserve’ and were referred to as IFRs at that time. It is ac-cepted, however, that the term ‘IFR’ has been largely superseded by the use of the term EWR or ecological water requirements.
- Full Text:
- Date Issued: 2012
- Authors: Hughes, Denis A , Forsyth, David A , Stassen, J J M , van Niekerk, E
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , report
- Identifier: http://hdl.handle.net/10962/438255 , vital:73446 , ISBN 978-1-4312-0296-6 , https://wrcwebsite.azurewebsites.net/wp-content/uploads/mdocs/1870%20-2-121.pdf
- Description: The purpose of the National Database is to create a central repository of Reserve or EWR determination results that can be accessed by DWA as well as their service providers to ensure that information is not lost and that the maximum benefit is gained from previous experience for future determinations. This document summa-rises the information content of the database, as well as providing guidelines for entering new data and using existing data. Reference to both Reserve and EWR de-terminations is used as some of the data that are included pre-date the official con-cept of the ecological ‘Reserve’ and were referred to as IFRs at that time. It is ac-cepted, however, that the term ‘IFR’ has been largely superseded by the use of the term EWR or ecological water requirements.
- Full Text:
- Date Issued: 2012
Incorporating uncertainty in water resources simulation and assessment tools in South Africa
- Hughes, Denis A, Kapangaziwiri, E, Mallory, S J, Wagener, T, Smithers, J
- Authors: Hughes, Denis A , Kapangaziwiri, E , Mallory, S J , Wagener, T , Smithers, J
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , report
- Identifier: http://hdl.handle.net/10962/438239 , vital:73445 , ISBN 978-1-4312-0128-0 , https://wrcwebsite.azurewebsites.net/wp-content/uploads/mdocs/18381.pdf
- Description: The main objective of the project was to contribute to the incorporation of uncer-tainty assessments in water resource decision making in South Africa, thereby quan-tifying the risks associated with specific decisions about planned future water re-source developments. This objective was supported by several specific aims: 1. De-velop an understanding of uncertainty and associated risks in water resource man-agement on the basis of literature and known practices, nationally and internation-ally. 2. Identify and characterise the main sources of uncertainty (focusing on cur-rent South African practice and typical situations of data availability). 3. Develop techniques and guidelines for quantifying the uncertainty associated with different models. This will include uncertainty in all relevant areas (hydrological, climate, economic, social, etc.). 4. Determine the effects of uncertainty on water resource management and identify what level of uncertainty is acceptable. 5. Develop guide-lines for the communication of uncertainty and the impacts to various stakeholder groups involved within water resource planning and management. This aim will need to address the issue of the links between uncertainty and risk. 6. Develop guidelines for incorporating uncertainty and the associated risk into water resource decision making processes. 7. Identify those areas of uncertainty that can be realistically re-duced and which will have the greatest impact on reducing the risks involved with water resource decision making.
- Full Text:
- Date Issued: 2011
- Authors: Hughes, Denis A , Kapangaziwiri, E , Mallory, S J , Wagener, T , Smithers, J
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , report
- Identifier: http://hdl.handle.net/10962/438239 , vital:73445 , ISBN 978-1-4312-0128-0 , https://wrcwebsite.azurewebsites.net/wp-content/uploads/mdocs/18381.pdf
- Description: The main objective of the project was to contribute to the incorporation of uncer-tainty assessments in water resource decision making in South Africa, thereby quan-tifying the risks associated with specific decisions about planned future water re-source developments. This objective was supported by several specific aims: 1. De-velop an understanding of uncertainty and associated risks in water resource man-agement on the basis of literature and known practices, nationally and internation-ally. 2. Identify and characterise the main sources of uncertainty (focusing on cur-rent South African practice and typical situations of data availability). 3. Develop techniques and guidelines for quantifying the uncertainty associated with different models. This will include uncertainty in all relevant areas (hydrological, climate, economic, social, etc.). 4. Determine the effects of uncertainty on water resource management and identify what level of uncertainty is acceptable. 5. Develop guide-lines for the communication of uncertainty and the impacts to various stakeholder groups involved within water resource planning and management. This aim will need to address the issue of the links between uncertainty and risk. 6. Develop guidelines for incorporating uncertainty and the associated risk into water resource decision making processes. 7. Identify those areas of uncertainty that can be realistically re-duced and which will have the greatest impact on reducing the risks involved with water resource decision making.
- Full Text:
- Date Issued: 2011
Ecological impacts of small dams on South African rivers Part 1: Drivers of change–water quantity and quality
- Mantel, Sukhmani K, Hughes, Denis A, Muller, Nikite W J
- Authors: Mantel, Sukhmani K , Hughes, Denis A , Muller, Nikite W J
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , report
- Identifier: http://hdl.handle.net/10962/438099 , vital:73435 , ISBN 1816-7950 , 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.
- Full Text:
- Date Issued: 2010
- Authors: Mantel, Sukhmani K , Hughes, Denis A , Muller, Nikite W J
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , report
- Identifier: http://hdl.handle.net/10962/438099 , vital:73435 , ISBN 1816-7950 , 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.
- Full Text:
- Date Issued: 2010
Ecological impacts of small dams on South African rivers Part 2: Biotic response–abundance and composition of macroinvertebrate communities
- Mantel, Sukhmani K, Muller, Nikite W J, Hughes, Denis A
- Authors: Mantel, Sukhmani K , Muller, Nikite W J , Hughes, Denis A
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , report
- Identifier: http://hdl.handle.net/10962/438087 , vital:73434 , ISBN 1816-7950 , https://wrcwebsite.azurewebsites.net/wp-content/uploads/mdocs/2354.pdf
- Description: This paper investigates the cumulative impacts of small dams on inver-tebrate communities in 2 regions of South Africa–the Western Cape and Mpumalanga. Previous research found reduced discharge, in-creased total dissolved salts, and a decrease in average score per tax-on (ASPT; collected using SASS4 methods) at sites with high density of small dams in their catchment. These changes in ASPT are investigat-ed using the invertebrate abundance data available in the River Health Programme. Multivariate analyses found differences in invertebrate communities in rivers with high densities of small dams in their catch-ment in foothill-gravel streams (in both Western Cape and Mpuma-langa) and in foothill-cobble streams (in Western Cape only). Opportun-istic taxa that are tolerant of pollution, and capable of exploiting various habitats, and those that prefer slower currents increased in numbers, while other taxa that are sensitive to pollution and disturbance declined in numbers. Some regional differences were noted possibly reflecting climatic differences between the regions. Since the results of this study are correlative, it highlights the need for a systematic (by sites and sea-sons) and detailed (at species level) collection of data to verify the re-sults of cumulative effects of small dams. This can further the devel-opment of a framework for small-dam construction and management that will limit their impact on river catchments.
- Full Text:
- Date Issued: 2010
- Authors: Mantel, Sukhmani K , Muller, Nikite W J , Hughes, Denis A
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , report
- Identifier: http://hdl.handle.net/10962/438087 , vital:73434 , ISBN 1816-7950 , https://wrcwebsite.azurewebsites.net/wp-content/uploads/mdocs/2354.pdf
- Description: This paper investigates the cumulative impacts of small dams on inver-tebrate communities in 2 regions of South Africa–the Western Cape and Mpumalanga. Previous research found reduced discharge, in-creased total dissolved salts, and a decrease in average score per tax-on (ASPT; collected using SASS4 methods) at sites with high density of small dams in their catchment. These changes in ASPT are investigat-ed using the invertebrate abundance data available in the River Health Programme. Multivariate analyses found differences in invertebrate communities in rivers with high densities of small dams in their catch-ment in foothill-gravel streams (in both Western Cape and Mpuma-langa) and in foothill-cobble streams (in Western Cape only). Opportun-istic taxa that are tolerant of pollution, and capable of exploiting various habitats, and those that prefer slower currents increased in numbers, while other taxa that are sensitive to pollution and disturbance declined in numbers. Some regional differences were noted possibly reflecting climatic differences between the regions. Since the results of this study are correlative, it highlights the need for a systematic (by sites and sea-sons) and detailed (at species level) collection of data to verify the re-sults of cumulative effects of small dams. This can further the devel-opment of a framework for small-dam construction and management that will limit their impact on river catchments.
- Full Text:
- Date Issued: 2010
Links between water temperatures, ecological responses and flow rates: a framework for establishing water temperature guidelines for the ecological reserve
- Rivers-Moore, Nick A, Hughes, Denis A, Mantel, Sukhmani K
- Authors: Rivers-Moore, Nick A , Hughes, Denis A , Mantel, Sukhmani K
- Date: 2008
- Subjects: To be catalogued
- Language: English
- Type: text , report
- Identifier: http://hdl.handle.net/10962/438295 , vital:73449 , ISBN 978-1-77005-738-8 , https://wrcwebsite.azurewebsites.net/wp-content/uploads/mdocs/KV214-CONSERVATION.pdf
- Description: Global ecosystems face unprecedented crises in habitat fragmentation, destruction and ultimately extinction (Groves, 2003), and of all the vary-ing ecological systems rivers are the most neglected and endangered (Groves, 2003; Driver, et al., 2005; Roux et al., 2005). The greatest threat to these systems is the loss or degradation of natural habitat and processes (Driver et al., 2005), and water temperatures, after flow vol-umes, are a primary abiotic driver of species patterns within river sys-tems. Stuckenberg (1969) highlighted the links between temperature, topography and faunal assemblages, while Rivers-Moore et al.(2004) highlights the major impacts of water temperatures on organisms, and illustrate how water temperatures are one of the primary environmental drivers structuring fish communities in the Sabie River, arguably the most icthyologically species-rich river in South Africa.
- Full Text:
- Date Issued: 2008
- Authors: Rivers-Moore, Nick A , Hughes, Denis A , Mantel, Sukhmani K
- Date: 2008
- Subjects: To be catalogued
- Language: English
- Type: text , report
- Identifier: http://hdl.handle.net/10962/438295 , vital:73449 , ISBN 978-1-77005-738-8 , https://wrcwebsite.azurewebsites.net/wp-content/uploads/mdocs/KV214-CONSERVATION.pdf
- Description: Global ecosystems face unprecedented crises in habitat fragmentation, destruction and ultimately extinction (Groves, 2003), and of all the vary-ing ecological systems rivers are the most neglected and endangered (Groves, 2003; Driver, et al., 2005; Roux et al., 2005). The greatest threat to these systems is the loss or degradation of natural habitat and processes (Driver et al., 2005), and water temperatures, after flow vol-umes, are a primary abiotic driver of species patterns within river sys-tems. Stuckenberg (1969) highlighted the links between temperature, topography and faunal assemblages, while Rivers-Moore et al.(2004) highlights the major impacts of water temperatures on organisms, and illustrate how water temperatures are one of the primary environmental drivers structuring fish communities in the Sabie River, arguably the most icthyologically species-rich river in South Africa.
- Full Text:
- Date Issued: 2008
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