A generic database and spatial interface for the application of hydrological and water resource models
- Authors: Hughes, Denis A , Forsyth, D A
- Date: 2006
- Language: English
- Type: text , Article
- Identifier: vital:7080 , http://hdl.handle.net/10962/d1012333
- Description: The paper discusses a software package that has been designed to enhance the efficiency of applying a range of hydrological and water resource simulation models. The SPATSIM (SPatial and Time Series Information Modeling) system has been developed in Delphi using MapObjects and incorporates a spatial data interface for access to the different types of information commonly associated with water resource analyses. All of the information is stored within database tables (Paradox by default) with generic structures. The structure and components of the system are briefly described and some example applications provided. The discussion identifies some of the criticisms that have been leveled at the software, the approach of the developers to user support and some possible future developments. The conclusions suggest that the development can be considered successful in that it has substantially improved the efficiency of the Institute for Water Research to undertake one of its core functions of hydrological model development and application.
- Full Text:
- Date Issued: 2006
Application of satellite-derived rainfall estimates to extend water resource simulation modelling in South Africa
- Authors: Sawunyama, Tendai , Hughes, Denis A
- Date: 2008
- Language: English
- Type: text , Article
- Identifier: vital:7089 , http://hdl.handle.net/10962/d1012419
- Description: Spatially interpolated rainfall estimates from rain-gauges are widely used as input to hydrological models, but deriving accurate estimates at appropriate space and time scales remain a major problem. In South Africa there has been a gradual decrease in the number of active rain-gauges over time. Satellite-based estimates of spatial rainfall are becoming more readily available and offer a viable substitute. The paper presents the potential of using Climate Prediction Center African daily precipitation climatology (CPCAPC) satellite-based datasets (2001-2006) to drive a Pitman hydrological model which has been calibrated using gauge-based rainfall data (1920-1990). However, if two sources of rainfall data are to be used together, it is necessary to ensure that they are compatible in terms of their statistical properties. A non-linear frequency of exceedance transformation technique was used to correct the satellite data to be more consistent with historical spatial rainfall estimates. The technique generated simulation results for the 2001 to 2006 period that were greatly improved compared to the direct use of the untransformed satellite data. While there remain some further questions about the use of satellite-derived rainfall data in different parts of the country, they do seem to have the potential to contribute to extending water resource modelling into the future.
- Full Text:
- Date Issued: 2008
Automated estimation and analyses of meteorological drought characteristics from monthly rainfall data
- Authors: Smakhtin, V U , Hughes, Denis A
- Date: 2007
- Language: English
- Type: text , Article
- Identifier: vital:7078 , http://hdl.handle.net/10962/d1009746
- Description: The paper describes a new software package for automated estimation, display and analyses of various drought indices – continuous functions of precipitation that allow quantitative assessment of meteorological drought events to be made. The software at present allows up to five different drought indices to be estimated. They include the Decile Index (DI), the Effective Drought Index (EDI), the Standardized Precipitation Index (SPI) and deviations from the long-term mean and median value. Each index can be estimated from point and spatially averaged rainfall data and a number of options are provided for months' selection and the type of the analysis, including a running mean, single value or multiple annual values. The software also allows spell/run analysis to be performed and maps of a specific index to be constructed. The software forms part of the comprehensive computer package, developed earlier and designed to perform the multitude of water resources analyses and hydro-meteorological data processing. The 7-step procedure of setting up and running a typical drought assessment application is described in detail. The examples of applications are given primarily in the specific context of South Asia where the software has been used.
- Full Text:
- Date Issued: 2007
Comparison of satellite rainfall data with observations from gauging station networks
- Authors: Hughes, Denis A
- Date: 2006
- Language: English
- Type: text , Article
- Identifier: vital:7079 , http://hdl.handle.net/10962/d1009748
- Description: Networks of ground-based hydro-meteorological observations are frequently sparse in developing countries and the situation is not improving. Part of the reason is the lack of resources available in countries which have more pressing economic and social issues. However, these are also the very countries where improved estimates of water resource availability are required. While hydrological models have the potential to provide the necessary information, without adequately accurate climate (rainfall, evaporation, etc.) input information, it is extremely difficult to establish models and generate representative water resource availability information. This paper reports on a preliminary analysis of the potential for using satellite derived rainfall data through a comparison with available gauge data for four basins in the southern Africa region. It is clear that the satellite data cannot be used directly in conjunction with historical gauge data. Specifically, the satellite data do not reflect the strong influences on precipitation of topography in some of the basins. However, the prospects of applying relatively straightforward adjustments are promising and further assessments appear to be justified.
- Full Text:
- Date Issued: 2006
Deployment, Maintenance And Further Development Of Spatsim-HDSF Volume
- 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
- 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
Ecological impacts of small dams on South African rivers Part 1: Drivers of change–water quantity and quality
- 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
- Authors: Mantel, Sukhmani K , Muller, Nikite W J , Hughes, Denis A
- Date: 2010
- Language: English
- Type: text , Article
- Identifier: vital:7095 , http://hdl.handle.net/10962/d1012437
- Description: This paper investigates the cumulative impacts of small dams on invertebrate communities in 2 regions of South Africa – the Western Cape and Mpumalanga. Previous research found reduced discharge, increased total dissolved salts, and a decrease in average score per taxon (ASPT; collected using SASS4 methods) at sites with high density of small dams in their catchment. These changes in ASPT are investigated 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 catchment in foothill-gravel streams (in both Western Cape and Mpumalanga) and in foothill-cobble streams (in Western Cape only). Opportunistic 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 seasons) and detailed (at species level) collection of data to verify the results of cumulative effects of small dams. This can further the development of a framework for small-dam construction and management that will limit their impact on river catchments.
- Full Text:
- Date Issued: 2010
Ecological impacts of small dams on South African rivers Part 2: Biotic response–abundance and composition of macroinvertebrate communities
- 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
ECOMAG Model: an evaluation for use in South Africa
- 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
Estimating rainfall and water balance over the Okavango River Basin for hydrological applications
- Authors: Wilk, J , Kniveton, D , Andersson, L , Layberry, R , Todd, M C , Hughes, Denis A
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:7084 , http://hdl.handle.net/10962/d1012343 , http://dx.doi.org/10.1016/j.jhydrol.2006.04.049
- Description: A historical database for use in rainfall-runoff modeling of the Okavango River Basin in Southwest Africa is presented. The work has relevance for similar data-sparse regions. The parameters of main concern are rainfall and catchment water balance, which are key variables for subsequent studies of the hydrological impacts of development and climate change. Rainfall estimates are based on a combination of in situ gauges and satellite sources. Rain gauge measurements are most extensive from 1955 to 1972, after which they are drastically reduced due to the Angolan civil war. The sensitivity of the rainfall fields to spatial interpolation techniques and the density of gauges were evaluated. Satellite based rainfall estimates for the basin are developed for the period from 1991 onwards, based on the Tropical Rainfall Measuring Mission (TRMM) and Special Sensor Microwave Imager (SSM/I) datasets. The consistency between the gauges and satellite estimates was considered. A methodology was developed to allow calibration of the rainfall-runoff hydrological model against rain gauge data from 1960 to 1972, with the prerequisite that the model should be driven by satellite derived rainfall products from 1990 onwards. With the rain gauge data, addition of a single rainfall station (Longa) in regions where stations earlier were lacking was more important than the chosen interpolation method. Comparison of satellite and gauge rainfall outside the basin indicated that the satellite overestimates rainfall by 20%. A non-linear correction was derived by fitting the rainfall frequency characteristics to those of the historical rainfall data. This satellite rainfall dataset was found satisfactory when using the Pitman rainfall-runoff model (Hughes, D., Andersson, L., Wilk, J., Savenije, H.H.G., this issue. Regional calibration of the Pitman model for the Okavango River. Journal of Hydrology). Intensive monitoring in the region is recommended to increase accuracy of the comprehensive satellite rainfall estimate calibration procedure.
- Full Text:
- Date Issued: 2006
Extending functionality and knowledge transfer of the Water Quality Systems Assessment Model
- 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
First steps in the development of a water temperature model framework for refining the ecological Reserve in South African rivers
- Authors: Rivers-Moore, Nick A , Hughes, Denis A , Mantel, Sukhmani K , Hill, Trevor R
- Date: 2008-10-05
- Language: English
- Type: text , Article
- Identifier: vital:7092 , http://hdl.handle.net/10962/d1012425
- Description: Ecological Reserve determination for rivers in South Africa presently does not include a water temperature component, in spite of its importance in determining species distribution patterns. To achieve this requires an understanding of how lotic thermographs from South African rivers differ from northern hemisphere rivers, to avoid mismanaging rivers based on incorrect regional assumptions. Hourly water temperatures from 20 sites in four river systems, representing a range of latitudes, altitudes and stream orders, were assessed using a range of metrics. These data were analysed using principal component analyses and multiple linear regressions to understand what variables a water temperature model for use in ecoregions within South Africa should include. While temperature data are generally lacking in low- and higher-order South African rivers, data suggest that South African rivers are warmer than northern hemisphere rivers. Water temperatures could be grouped into cool, warm and intermediate types. Based on temperature time series analyses, this paper argues that a suitable water-temperature model for use in ecological Reserve determinations should be dynamic, include flow and air temperature variables, and be adaptive through a heat exchange coefficient term. The inclusion of water temperature in the determination and management of river ecological Reserves would allow for more holistic application of the National Water Act's ecological management provisions. Water temperature guidelines added to the ecological Reserve could be integrated into heuristic aquatic monitoring programmes within priority areas identified in regional conservation plans.
- Full Text:
- Date Issued: 2008-10-05
Impact of climate change and development scenarios on flow patterns in the Okavango River
- Authors: Andersson, L , Wilk, J , Todd, M C , Hughes, Denis A , Earle, A , Kniveton, D , Layberry, R , Savenije, H H G
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:7086 , http://hdl.handle.net/10962/d1012346
- Description: This paper lays the foundation for the use of scenario modelling as a tool for integrated water resource management in the Okavango River basin. The Pitman hydrological model is used to assess the impact of various development and climate change scenarios on downstream river flow. The simulated impact on modelled river discharge of increased water use for domestic use, livestock, and informal irrigation (proportional to expected population increase) is very limited. Implementation of all likely potential formal irrigation schemes mentioned in available reports is expected to decrease the annual flow by 2% and the minimum monthly flow by 5%. The maximum possible impact of irrigation on annual average flow is estimated as 8%, with a reduction of minimum monthly flow by 17%. Deforestation of all areas within a 1 km buffer around the rivers is estimated to increase the flow by 6%. However, construction of all potential hydropower reservoirs in the basin may change the monthly mean flow distribution dramatically, although under the assumed operational rules, the impact of the dams is only substantial during wet years. The simulated impacts of climate change are considerable larger that those of the development scenarios (with exception of the high development scenario of hydropower schemes) although the results are sensitive to the choice of GCM and the IPCC SRES greenhouse gas (GHG) emission scenarios. The annual mean water flow predictions for the period 2020–2050 averaged over scenarios from all the four GCMs used in this study are close to the present situation for both the A2 and B2 GHG scenarios. For the 2050–2080 and 2070–2099 periods the all-GCM mean shows a flow decrease of 20% (14%) and 26% (17%), respectively, for the A2 (B2) GHG scenarios. However, the uncertainty in the magnitude of simulated future changes remains high. The simulated effect of climate change on minimum monthly flow is proportionally higher than the impact on the annual mean flow.
- Full Text:
- Date Issued: 2006
Impacts of Climate Change in Determining the Ecological Reserve
- 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
Implementing uncertainty analysis in water resources assessment and planning
- 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
Incorporating uncertainty in water resources simulation and assessment tools in South Africa
- 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
Informing the Responses of Water Service Delivery Institutions to Climate and Development Changes: A Case Study in the Amatole Region, Eastern Cape
- 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
Issues in contemporary geographical hydrology
- Authors: Hughes, Denis A
- Date: 2002
- Language: English
- Type: text , Article
- Identifier: vital:7083 , http://hdl.handle.net/10962/d1012340
- Description: Finding solutions to the many water resource utilisation problems that face South Africa has been the driving force behind a large part of the hydrological research that has been undertaken in the country. Any review of the methodology and past or present issues of hydrology in South Africa would find it difficult to distinguish between those that are part of engineering hydrology, and those that are part of geographical hydrology. Both have a great deal to contribute to solving the water resource management problems of South Africa and these contributions should be made in a co-operative framework. As will be demonstrated in the paper, the changing face of South Africa and the requirements of managing water in a transformed, democratic society have made the need for co-operation across various disciplines even more essential.
- Full Text: false
- Date Issued: 2002
Links between water temperatures, ecological responses and flow rates: a framework for establishing water temperature guidelines for the ecological reserve
- 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