scholarly journals Water availability and demand in the humid and arid regions within development regions of South Africa

1989 ◽  
Vol 8 (1) ◽  
pp. 9-11
Author(s):  
A. B. De Villiers ◽  
L. A. Van Wyk ◽  
W. Viviers
Keyword(s):  
South Africa ◽  
Water Supply ◽  
Water Availability ◽  
Arid Regions ◽  
Supply And Demand ◽  
Individual Development ◽  
Annual Rainfall ◽  
Great Promise ◽  
Drainage Basins ◽  
Average Annual Rainfall

A method has been developed to distinguish between water supply and demand in individual development regions which contain distinct humid and arid to subarid areas. Development regions A and D have heterogeneous climatic distributions within their borders and are dealt with in this regard. These regions can be divided into arid and humid areas. A magisterial district was considered to be humid when the average annual rainfall is more than 400 mm over more than 50 percent of its total area. The water availability and demand for each of the districts (whether humid or arid) were calculated on a pro rata basis according to the area each district occupies within the various secondary drainage basins. The results obtained in this study show great promise to divide the regions into arid and humid areas for more accurate and detailed planning within the development regions.

scholarly journals Water availability and demand in the development regions of South Africa

1988 ◽  
Vol 7 (2) ◽  
pp. 87-90
Author(s):  
A. B. De Villiers ◽  
W. Viviers ◽  
L. A. Van Wyk
Keyword(s):  
South Africa ◽  
Water Supply ◽  
Water Availability ◽  
Supply And Demand ◽  
Water Supply And Demand ◽  
Made In

The availability of water data in the development regions is at present insufficient. This is due to the fact that water supply and demand is calculated for the physical drainage regions (watersheds), while the development regions do not correspond with the drainage regions. The necessary calculations can accordingly presently not be made. In this paper this problem is addressed.

Analysis on Water Resources Supply and Demand Balance of Rural Land Remediation Project in Baishan City, Jilin Province

2013 ◽  
Vol 295-298 ◽  
pp. 2132-2137
Author(s):  
Xiao Ling Xu ◽  
Xu Feng Liang ◽  
Xiu Juan Liang ◽  
Chang Lai Xiao
Keyword(s):  
Water Resources ◽  
Water Supply ◽  
Water Availability ◽  
Water Demand ◽  
Influence Factor ◽  
Supply And Demand ◽  
Rural Land ◽  
Project Area ◽  
Groundwater Availability ◽  
Relevant Calculation

Water resources are an important influence factor of land remediation. As support of food production, analysis of water resources supply and demand balance is an important part and technical support of the construction. According to some relevant calculation formulas on water resources assessment, after forecast of water demand and the calculation of water supply, in the project area of the demonstration construction of whole rural land remediation in Baishan City, the average water availability for many years is 8990.1 thousand m3 each year, in which surface water availability is 7210.6 thousand m3, groundwater availability is 1579.4 thousand m3. Water demand is 5552.4 thousand m3 in 2015, in which water demand for life 4165.2 thousand m3; water demand for agricultural irrigation is 1387.2 thousand m3. Water supply is more than water demand; the results show that there is a slight surplus of water resources in the region. The basic supply-demand balance can be achieved in conditions of the design of water supply project in the project area.

scholarly journals Rainfall and river flow trends for the Western Cape Province, South Africa

2019 ◽  
Vol 115 (9/10) ◽  
Author(s):  
Rakhee Lakhraj-Govender ◽  
Stefan W. Grab
Keyword(s):  
Climate Change ◽  
South Africa ◽  
River Flow ◽  
Supply And Demand ◽  
Temporal Distribution ◽  
Annual Rainfall ◽  
Western Cape ◽  
Western Cape Province ◽  
Winter Rainfall ◽  
Intergovernmental Panel

Climate change has the potential to alter the spatio-temporal distribution of rainfall, subsequently affecting the supply and demand of water resources. In a water-stressed country such as South Africa, this effect has significant consequences. To this end, we investigated annual and winter rainfall and river flow trends for the Western Cape Province over two periods: 1987–2017 and 1960–2017. Annual rainfall for the most recent 30-year period shows decreasing trends, with the largest magnitude of decrease at the SA Astronomical Observatory rainfall station (-54.38 mm/decade). With the exception of the significant decreasing winter rainfall trend at Langewens (-34.88 mm/decade), the trends vary between stations for the period 1960–2017. For the period 1987–2017, statistically significant decreasing winter trends were found at four of the seven stations, and range from -6.8 mm/decade at Cape Columbine to -34.88 mm/decade at Langewens. Similarly, the magnitudes of decreasing winter river flow at Bree@Ceres and Berg@Franschoek are greater for the more recent 30-year period than for 1960–2017. Correlation coefficients for Vilij@Voeliv rainfall and four river flow stations Berg@Franschoek, Bree@Ceres, Wit River@Drosterkloof and Little Berg@Nieuwkloof) are stronger for shorter periods (i.e. 1987–2017 and 2007–2017) than that for the longer period, 1960–2017. The Intergovernmental Panel on Climate Change emphasises the importance of studies to assist with model prediction uncertainties. To this end, our study expands the understanding of regional hydrological responses to rainfall change in the water stressed region of the Western Cape Province.

MODELING WATER SUPPLY AND DEMAND FOR EFFECTIVE WATER MANAGEMENT ALLOCATION IN SELANGOR

2016 ◽  
Vol 78 (5-5) ◽  
Author(s):  
Nurul Nadiah Mohd Firdaus Hum ◽  
Suhaimi Abdul Talib
Keyword(s):  
Population Growth ◽  
Water Supply ◽  
Water Availability ◽  
Supply And Demand ◽  
The State ◽  
Economic Sectors ◽  
Weap Model ◽  
Water Savings ◽  
Water Supply And Demand ◽  
The Impact

Water in Selangor is getting scarce due to its rapid economic growth. A fast growing population and expanding urbanization in the state creates new demands for water availability. Thus, the present study analyses the effects of three different scenarios using Water Evaluation and Planning (WEAP) model to evaluate the plausible future water scenarios of water availability in Selangor. The first scenario is business as usual which is later referred to as reference in this study. Second, higher population growth and the third is the application of the demand side management onto the reference and higher population growth scenario. These scenarios were then used to calculate the impact on the supply – demand gap by the year 2050. Two catchments were used namely Selangor and Langat to illustrate the water supply and demand in the state of Selangor. The study then generates information for use in managing water allocations amongst economic sectors in Selangor as the explicit accounting in the description of the water supply and demand among the urban and industry water usage is advocated. Such detailed scenario simulation and the inclusion of previously unaccounted for factors like the higher population growth and water savings management can help to create awareness of potential future problems, inform water practices and suggest management alternatives. Results show that with proper water savings measures, water deficit within Selangor will be significantly reduced.  

scholarly journals Study of the management efficiency of the drinking water supply in arid areas: case of Bechar city (southwest of Algeria)

2019 ◽  
Vol 9 (8) ◽  
Author(s):  
Mohammed Amin Kendouci ◽  
Ali Bendida ◽  
Saliha Mebarki ◽  
Benali Kharroubi
Keyword(s):  
Drinking Water ◽  
Water Supply ◽  
Water Pressure ◽  
Treatment Plant ◽  
Drinking Water Treatment ◽  
Water Treatment Plant ◽  
Annual Rainfall ◽  
Management Efficiency ◽  
Average Annual Rainfall ◽  
The City

Abstract Bechar, a typical Saharan city with an arid climate, receives an average annual rainfall of around 72 mm. Two resources ensure the supply of drinking water to the city of Bechar; the first comes from a catchment field consisting of eight boreholes, and the second comes from the Djorf Torba dam located in the west at about 45 km where is located the drinking water treatment plant. Water scarcity and water supply disruption have caused residents of Bechar city connected to the water supply system to invest in relatively expensive storage and pumping facilities to meet their domestic needs. The survey was conducted on a sample of 20% of the population of Bechar city in a period of 4 months. Through the survey, we have reached that 74% of citizens of Bechar city are not satisfied with the quality and quantity of water and 59% of respondents are not satisfied with the water pressure and are therefore forced to use the pumps.

Analysis of Water Resources Supply and Demand Balance of Rural Land Remediation Project Area in Fuyu County, Jilin Province

2012 ◽  
Vol 212-213 ◽  
pp. 609-614
Author(s):  
Xiao Ling Xu ◽  
Xu Feng Liang ◽  
Xiu Juan Liang ◽  
Chang Lai Xiao
Keyword(s):  
Water Resources ◽  
Water Supply ◽  
Water Availability ◽  
Water Demand ◽  
Influence Factor ◽  
Supply And Demand ◽  
Rural Land ◽  
Project Area ◽  
Groundwater Availability ◽  
Relevant Calculation

Water resources are an important influence factor of land remediation. As support of food production, analysis of soil and water resources supply and demand balance is an important part and technical support of the construction. According to some relevant calculation formulas on water resources assessment, after forecast of water demand and the calculation of water supply, in the project area of the demonstration construction of whole rural land remediation in Fuyu County, the average water availability for many years is 70581.6 thousand m3 each year, including surface water availability 57003.3 thousand m3 and groundwater availability 13578.3 thousand m3. Water demand is 58806.2 thousand m3 in 2015; including water demand for life 5150.9 thousand m3 and water demand for agricultural irrigation 53655.3 thousand m3. Water supply is more than water demand; the basic supply-demand balance can be achieved in conditions of the design of water supply project.

scholarly journals Modelling the water energy nexus: should variability in water supply impact on decision making for future energy supply options?

2018 ◽  
Vol 376 ◽  
pp. 3-8 ◽  
Author(s):  
James D. S. Cullis ◽  
Nicholas J. Walker ◽  
Fadiel Ahjum ◽  
Diego Juan Rodriguez
Keyword(s):  
South Africa ◽  
Developing Countries ◽  
Water Supply ◽  
Water Availability ◽  
Energy Supply ◽  
Power Stations ◽  
Energy Technologies ◽  
Water Demands ◽  
Cost Curves ◽  
Water Energy Nexus

Abstract. Many countries, like South Africa, Australia, India, China and the United States, are highly dependent on coal fired power stations for energy generation. These power stations require significant amounts of water, particularly when fitted with technology to reduce pollution and climate change impacts. As water resources come under stress it is important that spatial variability in water availability is taken into consideration for future energy planning particularly with regards to motivating for a switch from coal fired power stations to renewable technologies. This is particularly true in developing countries where there is a need for increased power production and associated increasing water demands for energy. Typically future energy supply options are modelled using a least cost optimization model such as TIMES that considers water supply as an input cost, but is generally constant for all technologies. Different energy technologies are located in different regions of the country with different levels of water availability and associated infrastructure development and supply costs. In this study we develop marginal cost curves for future water supply options in different regions of a country where different energy technologies are planned for development. These water supply cost curves are then used in an expanded version of the South Africa TIMES model called SATIM-W that explicitly models the water-energy nexus by taking into account the regional nature of water supply availability associated with different energy supply technologies. The results show a significant difference in the optimal future energy mix and in particular an increase in renewables and a demand for dry-cooling technologies that would not have been the case if the regional variability of water availability had not been taken into account. Choices in energy policy, such as the introduction of a carbon tax, will also significantly impact on future water resources, placing additional water demands in some regions and making water available for other users in other regions with a declining future energy demand. This study presents a methodology for modelling the water-energy nexus that could be used to inform the sustainable development planning process in the water and energy sectors for both developed and developing countries.

scholarly journals Progressive water deficits during multi-year droughts in central-south Chile

2020 ◽  
Author(s):  
Camila Alvarez-Garreton ◽  
Juan Pablo Boisier ◽  
René Garreaud ◽  
Jan Seibert ◽  
Marc Vis
Keyword(s):  
Water Supply ◽  
Arid Regions ◽  
Snow Accumulation ◽  
Annual Rainfall ◽  
General Question ◽  
Runoff Generation ◽  
Water Deficits ◽  
Moderate Drought ◽  
Central South ◽  
Semi Arid

Abstract. A decade-long (2010–2019) period with precipitation deficits in central-south Chile (30–41º S), the so-called megadrought (MD), has led to larger than expected hydrological response and water deficits, indicating an intensification in drought propagation. We used the CAMELS-CL dataset and simulations from the HBV hydrological model to explore the causes of such intensification. Across 124 basins with varying snow/rainfall regimes, we compared annual rainfall-runoff (R-R) relationships and runoff generation mechanisms before and during the MD, and identified those catchments where drought propagation was intensified. We show that catchments’ hydrological memory -mediated by groundwater flows- is a key control of drought propagation intensity, and that baseflow contribution to runoff is positively correlated with snow accumulation preceding the year affected by a drought. Hence, under persistent drought conditions, snow-dominated catchments progressively generate less water, compared with their historical behaviour, notably affecting the semi-arid regions in central Chile. Finally, we addressed a general question: what is worse, an extreme single year drought or a persistent moderate drought? In semi-arid regions, where water provision strongly depends on both the current and previous precipitation seasons, the worst scenario would be an extreme meteorological drought following consecutive years of precipitation below average. In temperate regions of southern Chile, where catchments have more pluvial regimes, hydrologic memory is still an important factor, but water supply is more strongly dependant on the meteorological conditions of the current year, and therefore an extreme drought would have a higher impact on water supply than a persistent but moderate drought.

scholarly journals POTENTIAL CONSTRAINT OF RAINFALL AVAILABILITY ON THE ESTABLISHMENT AND EXPANSION OF AGROFORESTRY IN THE MOPANI DISTRICT, LIMPOPO PROVINCE IN SOUTH AFRICA

AGROFOR ◽  
2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Phokele MAPONYA ◽  
Casper MADAKADZE ◽  
Nokwazi MBILI ◽  
Zakheleni DUBE ◽  
Thabo NKUNA ◽  
...  
Keyword(s):  
South Africa ◽  
Sampling Technique ◽  
Limpopo Province ◽  
Annual Rainfall ◽  
Agricultural Crops ◽  
Sweet Potatoes ◽  
Annual Average ◽  
Woody Perennial ◽  
Average Annual Rainfall ◽  
Average Rainfall

Agroforestry is a land use system that includes the use of woody perennial and agricultural crops and animals in combination to achieve beneficial ecological and economical interactions for food, fiber and livestock production. South Africa is considered a semi – arid country vulnerable to water stress, particularly drought. Limpopo Province average annual rainfall is 600mm and the threshold for rainfall agriculture is averaged at 250mm annually. In terms of forestry, rainfall needs to be higher than 750mm per annum to sustain commercial forestry. The objective of the study was to determine the potential constraint of rainwater on the establishment and expansion of agroforestry in Mopani district, Limpopo Province. A purposive sampling technique was used to select 62 agrosilviculture community growers and were spread on the 20ha SAFCOL forestland and each grower was allocated a row of 3226m2 (1ha = 10000m2; 20ha * 10000 = 200000m2/62) for production. Quantitative and qualitative designs were used. The results were based on the month the data collection started: September 2019 rainfall results indicated that there was generally good rainfall (25 - 50mm) in the agroforestry sites as compared to the agricultural open field areas. October 2019 rainfall situation improved with an increase in rainfall (51 - 100mm). During November and December 2019, increasing rainfall was experienced at 100 - 200mm and 175 - 250mm, respectively. The last three rainfall status (33rd, median and 66th percentiles) indicated the estimates of rainfall in the future years. It estimated annual rainfalls at 601 and +1000mm; +1000mm and +1000mm across 33rd, 50th and 66th percentiles, respectively. This rainfall situation is well above the Limpopo Province annual average rainfall, agriculture and forestry thresholds. Currently, the eucalyptus trees were integrated with other crops including maize, sweet potatoes, groundnuts and bambara nuts. It is thus recommended that the establishment and expansion of agroforestry be carried out in the identified suitable areas.

Sign in / Sign up

Export Citation Format

Share Document