DOCSLIB.ORG

Waterresearch Commission

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Waterresearch Commission WATERRESEARCH COMMISSION LONG TERM SALT BALANCE OF THE VAALHARTS IRRIGATION SCHEME C E Herold and A K Bailey REPORT TO THE WATERRESEARCH COMMISSION by STEWART SCOTT INCORPORATED (Consulting Engineers) P O Box 784506, Sandton, 2146 12/07/1996 WRC Report No.: 420/1/96 ISBN No.: 1 86845 0414 (i) EXECUTIVE SUMMARY BACKGROUND AND MOTIVATION Vaalharts is the largest irrigation scheme in the Republic of South Africa. The Vaal River is the source of the water supply to the scheme. Since the commissioning of Vaalharts in the mid-thirties, the salinity of the supply water has deteriorated substantially due to large scale urban, industrial and mining developments in the Middle Vaal. A study of the Harts River carried out by Stewart Sviridov and Oliver in 1987 on behalf of the Department of Water Affairs (DWA) concluded that between 1935 and 1984 less than 20 percent of the salt contained in the water supplied to Vaalharts was released via return flows to the Harts River. This represents an overall accumulation of approximately 3 million tons of salt. Implications for the Vaal and Orange River systems Salinisation of the Vaal River has already led to serious water quality problems in the lower Vaal. The return of all of the salt contained in the irrigation water supplied to Vaalharts would have put an additional 100 000 tons of salt into the Lower Vaal each year, with serious economic consequences for downstream users. If this proves to be only a temporary phenomenon (i.e. lagged system response) then continued salinisation of the Middle Vaal could jeopardise all irrigation schemes downstream of the Vaal-Harts confluence. In this regard, even the Orange River is threatened, seeing as its dilution factor will be reduced by the expected eventual removal of a further 2200 million cubic metres of fresh water via the Lesotho Highlands Water Project. Even if most of the unaccounted for salt has been permanently removed via percolation (through the calcrete layer that underlies the whole scheme) into deeper groundwater, it is likely that in future the salt removal rate will be reduced because of interception of drainage water by the recently installed sub-surface drains. Increased water allocations could also increase the leaching fraction, and hence the proportion of salt returned to the Harts River. Key questions The above considerations raise some important questions regarding the fate of the unaccounted for salt: Were the findings of the 1987 DWA study correct? (i.e. has most of the salt contained in the water supplied to Vaalharts been retained?) If so, what became of the salt? Has the salt been permanently removed from the surface drainage system, or has sub- surface storage merely delayed the response of the system to the sharp rise in the salinity of Vaal River water that commenced in the late seventies? Under what circumstances (if any) can the salt be expected to be returned to the surface drainage system? How will the recent provision of irrigation under-drains affect the proportion of salt removed? (ii) How will increased irrigation water allocations affect the salt removal? The implications of continued salt inputs to the Vaalharts irrigation scheme warranted a research study aimed at answering the key questions posed above. Expected benefits of study Answers to the key questions set out above were expected to provide the following benefits: Place water resource managers in a better position to anticipate the consequences of upstream developments and timeously implement appropriate water quality management strategies. Provide a better understanding of the overall salt balance of the Vaalharts irrigation scheme. This will serve to improve the calibration of the hydro-salinity models currently used by the Department of Water Affairs and Forestry (DWAF) in planning and managing the water resources of the Vaal River system. Determine if a more comprehensive multi-disciplinary research project to study the circulation and storage of salt in the Vaalharts irrigation scheme is warranted. Highlight the need for appropriate steps to be taken to collect the data required to monitor the long term response of the system and provide the information required for the second phase of the study. AIMS The stated aims of this study were as follows: • Quantify the long term historical macro-scale water and salt balance (in terms of both total dissolved salts (TDS) and its main ionic constituents) of the Vaalharts irrigation scheme to determine the extent of salt loss or accumulation. • Analyze available flow and water quality records to quantify the effect of the sub- surface drains (the installation of which commenced in the mid-seventies) on irrigation return flow volumes, TDS loads and TDS composition. • Study available agricultural, meteorological, hydrological, water quality, soils and geo- hydrological data to gain an understanding of the underlying hydro-salinity processes. • Where necessary, propose and initiate additional monitoring and field investigations to supplement the available data. The Water Research Commission decided on a two phase approach. The research reported on in this document is for the first phase, the primary purpose of which is to obtain an improved assessment of the situation and definition of the problem. The second phase was envisaged to involve an in-depth multi-disciplinary study of the processes taking place in the Vaalharts irrigation scheme. Commencement of the second phase is dependant on the findings of the first phase. r:\vnalliari\rcpDrt\vaalhan.doc (iii) As the first phase is essentially a preliminary investigation, the methodology has been kept as simple as possible. As far as possible existing data was used, with little or no additional sampling, field experiments or new model development. The main tasks are outlined below. TASKS UNDERTAKEN IN TERMS OF CONTRACT • Literature survey A literature survey has been carried out to identify studies of a similar nature that have been carried out elsewhere. In particular, relevant reports on studies carried out on the Vaalharts irrigation scheme itself have been examined. • Macro-scale water and salt balance The macro-scale water and salt balance was based on river monitoring in the Vaal and Harts Rivers and did not involve detailed studies of individual plots or irrigation blocks. Available hydrologica!, water quality, meteorological, water use and other relevant data were collected and entered into a project data base. Early flow and water quality records have been examined and patched using hydro-salinity models to estimate the water and salt loads supplied to and returned by the Vaalharts irrigation scheme. Computer software already developed in-house by the Consultants was used to clieck and patch deficient flow and water quality records. Existing hydro-salinity models were used to simulate the long term salt balance of the Vaalharts irrigation scheme. • Effect of sub-surface drains Available data was analyzed in an attempt to detect the effect of the recent installation of extensive sub-surface drains on the global percentage return flow and salt export. Hydro-salinity modelling was used to eliminate the effect of long term hydrological fluctuations that tend to mask water quality trends. • Hypothesise processes The results of the salt balance analyses were examined, together with relevant papers and reports and available agricultural, meteorological, water quality, soils and geohydrological data to gain an insight into the dominant processes controlling the storage and release of salt at Vaalharts. The most likely explanations for the apparent retention of salt at Vaalharts have been hypothesised. Cost-effective means of testing these hypotheses have been sought. • Monitoring proposals Proposals have been made for additional monitoring and field experiments required to validate the main hypotheses put forward regarding the processes by which salts are being accumulated at Vaalharts. f:\vaalhan\repotl\violhart.doc (iv) CONCLUSIONS The following conclusions can be drawn from the results of the study: • Parallels with other irrigation schemes The history of civilisations, as well as better documented more recent cases, indicates that large irrigation schemes such as Vaalharts have the capacity to accumulate very large volumes of irrigation water in the groundwater. It can be deduced that the change in storage in the groundwater represents the potential to store large tonnages of salt. The history of the Indus Scheme in Pakistan (which was commissioned during the same decade as Vaalharts Irrigation Scheme), as well as that of Vaalharts itself, demonstrates that the raising of the groundwater table can take a number of decades. It follows that during this period both water and salt will be accumulated. This provides a plausible mechanism for the large accumulation of salt in Vaalharts estimated in a previous study. • Data deficiencies A surprisingly large amount of basic information regarding the historical development of the Vaalharts Irrigation Scheme (such as irrigated areas, volumes of water supplied, cropping patterns, etc.) appears to be unobtainable. This necessitated patching by means of interpolation and extrapolation. The flow records for Spitskop Dam (C3R002), Espagsdrift weir (C3H007) and Mt. Rupert weir (C3H013) were found to be inaccurate. An investigation was carried out by the DWAF in Bloemfontein and a number of problems were identified with regard to the streamflow gauging operation. A report was compiled by them and sent to the DWAF in Pretoria who revised certain discharge table (DT) and streamflow data. • Hydro-salinity modelling The hydro-salinity water quality model WQT has been calibrated successfully for both the Upper Harts (i.e the catchment upstream of Taung weir) and Middle Harts catchments (i.e the catchment downstream of Taung weir - C3H003 up to Mt. Rupert weir - C3HO13). The calibrated model was then used to simulate conditions up to the year 2030. Owing to the inaccuracies in the flow gauging at key hydrological stations as well as the data deficiencies mentioned above, it was to be expected that the modelled values would not fit the observed values that well.
Load more

Recommended publications
  • Ganspan Draft Archaeological Impact Assessment Report
    CES: PROPOSED GANSPAN-PAN WETLAND RESERVE DEVELOPMENT ON ERF 357 OF VAALHARTS SETTLEMENT B IN THE PHOKWANE LOCAL MUNICIPALITY, FRANCES BAARD DISTRICT MUNICIPALITY, NORTHERN CAPE PROVINCE Archaeological Impact Assessment Prepared for: CES Prepared by: Exigo Sustainability ARCHAEOLOGICAL IMPACT ASSESSMENT (AIA) ON ERF 357 OF VAALHARTS SETTLEMENT B FOR THE PROPOSED GANSPAN-PAN WETLAND RESERVE DEVELOPMENT, FRANCES BAARD DISTRICT MUNICIPALITY, NORTHERN CAPE PROVINCE Conducted for: CES Compiled by: Nelius Kruger (BA, BA Hons. Archaeology Pret.) Reviewed by: Roberto Almanza (CES) DOCUMENT DISTRIBUTION LIST Name Institution Roberto Almanza CES DOCUMENT HISTORY Date Version Status 12 August 2019 1.0 Draft 26 August 2019 2.0 Final 3 CES: Ganspan-pan Wetland Reserve Development Archaeological Impact Assessment Report DECLARATION I, Nelius Le Roux Kruger, declare that – • I act as the independent specialist; • I am conducting any work and activity relating to the proposed Ganspan-Pan Wetland Reserve Development in an objective manner, even if this results in views and findings that are not favourable to the client; • I declare that there are no circumstances that may compromise my objectivity in performing such work; • I have the required expertise in conducting the specialist report and I will comply with legislation, including the relevant Heritage Legislation (National Heritage Resources Act no. 25 of 1999, Human Tissue Act 65 of 1983 as amended, Removal of Graves and Dead Bodies Ordinance no. 7 of 1925, Excavations Ordinance no. 12 of 1980), the
    [Show full text]
  • SIBU and the Crisis of Water Service Delivery in Sannieshof, North West Province
    SIBU and the crisis of water service delivery in Sannieshof, North West Province C GOUWS, I MOEKETSI, S MOTLOUNG, J TEMPELHOFF, G VAN GREUNING AND L VAN ZYL* Abstract In 2007 the residents of the town of Sannieshof in North West Province declared a dispute with the Tswaing Local Municipality on the grounds that the state of local service delivery left much to be desired. The ratepayers then formed the Sannieshof Inwoners Belastingbetalers Unie (SIBU) which literally took over the functions of local government of the town, functioning as a local government within a local government. This article provides a historical narrative of the conflict between SIBU and Tswaing Local Municipality, a dispute which was taken as far as the provincial High Court. Then follows an outline of conditions in Sannieshof and the townships of Agisanang and Phelindaba. Attention is given to the perceptions of local residents on the prevalent conditions, specifically in respect of water supply and sanitation service delivery. In the third section there are some theoretical perspectives on political culture, socialisation and happiness. A debate is provided on how these phenomena manifest under existing conditions in Sannieshof, and more particularly, in its adjacent townships of Agisanang and Phelindaba. Keywords: Sannieshof Inwoners Belastingbetalers Unie (SIBU), North West Province, service delivery, water supply, sanitation, Tswaing Local Municipality. Disciplines: History, Political Science, Tourism Studies and Public Management and Administration, Industrial Psychology and Wellness Studies. Introduction In November 2007, irate ratepayers of the towns Sannieshof, Ottosdal and Delareyville in South Africa’s North West Province, declared a dispute with Tswaing Local Municipality, the local authority responsible for their municipal services.1 Using the Municipal Finance (Management) Act, 56 of 2003,2 the Municipal Structures Act, 117 of 1998,3 and the Municipal Systems Act, 32 * Research Niche Area for the Cultural Dynamics of Water (CuDyWat).
    [Show full text]
  • Palaeontological Impact Assessment May Be Significantly Enhanced Through Field Assessment by a Professional Palaeontologist
    PALAEONTOLOGICAL HERITAGE ASSESSMENT: COMBINED DESKTOP & FIELD- BASED STUDY Proposed Meerkat Solar Power Plant on Portion 3 (Portion of Portion 2) of the Farm Vyflings Pan 598 near Vryburg, Naledi Local Municipality, North-West Province John E. Almond PhD (Cantab.) Natura Viva cc, PO Box 12410 Mill Street, Cape Town 8010, RSA [email protected] February 2016 EXECUTIVE SUMMARY The company Meerkat Solar Power Plant (RF) (Pty) Ltd is proposing to develop up to 115 MW photovoltaic solar facility, known as the Meerkat Solar Power Plant, on Portion 3 (Portion of Portion 2) of the Farm Vyflings Pan 598, IN Registration Division, Province of the North-West. The Meerkat Solar Power Plant study area is entirely underlain by late Archaean (c. 2.6 billion year-old) sedimentary rocks of the Schmidtsdrif Subgroup (Ghaap Group, Transvaal Supergroup). These mainly comprise shallow marine siliciclastic sediments and possible lavas of the Vryburg Formation plus carbonate sediments of the Boomplaas Formation. Field assessment suggests that stromatolite-bearing carbonate rocks are not present at surface within the Vryburg and Bomplaas Formation outcrop areas in the study area. The overlying superficial sediments (e.g. sandy soils, calcretised pan deposits) are of low palaeontological sensitivity. It is concluded that, with or without mitigation, the overall impact of the proposed Meerkat Solar Power Plant on Farm Vyflings Pan 598 is of NEGATIVE LOW SIGNIFICANCE in palaeontological heritage terms. Should significant fossil remains - such as well-preserved stromatolites - be exposed during construction, the responsible Environmental Control Officer should safeguard these, preferably in situ. The South African Heritage Resources Authority (SAHRA) should be alerted as soon as possible (Contact details: Mrs Colette Scheermeyer, P.O.
    [Show full text]
  • Review of Existing Infrastructure in the Orange River Catchment
    Study Name: Orange River Integrated Water Resources Management Plan Report Title: Review of Existing Infrastructure in the Orange River Catchment Submitted By: WRP Consulting Engineers, Jeffares and Green, Sechaba Consulting, WCE Pty Ltd, Water Surveys Botswana (Pty) Ltd Authors: A Jeleni, H Mare Date of Issue: November 2007 Distribution: Botswana: DWA: 2 copies (Katai, Setloboko) Lesotho: Commissioner of Water: 2 copies (Ramosoeu, Nthathakane) Namibia: MAWRD: 2 copies (Amakali) South Africa: DWAF: 2 copies (Pyke, van Niekerk) GTZ: 2 copies (Vogel, Mpho) Reports: Review of Existing Infrastructure in the Orange River Catchment Review of Surface Hydrology in the Orange River Catchment Flood Management Evaluation of the Orange River Review of Groundwater Resources in the Orange River Catchment Environmental Considerations Pertaining to the Orange River Summary of Water Requirements from the Orange River Water Quality in the Orange River Demographic and Economic Activity in the four Orange Basin States Current Analytical Methods and Technical Capacity of the four Orange Basin States Institutional Structures in the four Orange Basin States Legislation and Legal Issues Surrounding the Orange River Catchment Summary Report TABLE OF CONTENTS 1 INTRODUCTION ..................................................................................................................... 6 1.1 General ......................................................................................................................... 6 1.2 Objective of the study ................................................................................................
    [Show full text]
  • Frances Baard District Municipality: Proposed Upgrading of an Anglo Boer War Blockhouse on a Portion of Warrenton Erf 1, Warrenton, Northern Cape Province
    FRANCES BAARD DISTRICT MUNICIPALITY: PROPOSED UPGRADING OF AN ANGLO BOER WAR BLOCKHOUSE ON A PORTION OF WARRENTON ERF 1, WARRENTON, NORTHERN CAPE PROVINCE Archaeological Impact Assessment Prepared for: Frances Baard District Municipality Prepared by: Exigo Sustainability -i- Firefly Investments 224: Platinum Solar Park Project Archaeological Impact Assessment Report HERITAGE IMPACT ASSESSMENT ON A PORTION OF WARRENTON ERF 1 FOR THE PROPOSED UPGRADING OF AN ANGLO BOER WAR BLOCKHOUSE, WARRENTON, NORTHERN CAPE PROVINCE Conducted on behalf of: Frances Baard District Municipality Exigo Sustainability Compiled by: Nelius Kruger (BA, BA Hons. Archaeology Pret.) Reviewed by: Joh-ne Jansen (Frances Baard District Municipality) Document History Document Version 1 (Draft) – 25 March 2016 -i- Firefly Investments 224: Platinum Solar Park Project Archaeological Impact Assessment Report Although Exigo Sustainability exercises due care and diligence in rendering services and preparing documents, Exigo Sustainability accepts no liability, and the client, by receiving this document, indemnifies Exigo Sustainability and its directors, managers, agents and employees against all actions, claims, demands, losses, liabilities, costs, damages and expenses arising from or in connection with services rendered, directly or indirectly by Exigo Sustainability and by the use of the information contained in this document. This document contains confidential and proprietary information equally shared between Exigo Sustainability. and Frances Baard District Municipality, and is protected by copyright in favour of these companies and may not be reproduced, or used without the written consent of these companies, which has been obtained beforehand. This document is prepared exclusively for Frances Baard District Municipality and is subject to all confidentiality, copyright and trade secrets, rules, intellectual property law and practices of South Africa.
    [Show full text]
  • Presentation Update Harts River 2017.Pdf
    2017 NOTE Present Project: Prospecting Rights still held or applied for. Historic Project: This refers to the areas and work completed on the entire Project from day one. Introduction The historic target area covered a large area held under six (6) different Prospecting Rights which were applied for sequentially as more information on the deposit became available (Historic Project). The obtaining of such a large area was necessary as there are often large variations in the nature and potential of these alluvial deposits. Some drilling was done on most of these Prospecting Right areas (areas consist of one to several farms with different land owners) and the areas of higher potential were kept (Documented under the heading Present Project). It is necessary to include the results of the work done on the Historic Project, which includes the three (3) Rights held at present, as the work done outside the Present Project speaks to the potential of the Present Project and because the major portion of the test mining was done on the farm Zamenkomst (outside Present Project). On Zamenkomst only a small portion of the good gravel was preserved and mined out (Prospecting Right terminated). At the time, when this test mining was carried out, no other Prospecting Rights were available and the contractors moved else ware. It is important to note that all Test Mining was carried out with no cost to the “Company” (Contractors sold the Diamonds for their account and only the data and results of the Test Mining was retained by the “Company”). The only costs carried by the “Company” was Drilling and Salaries.
    [Show full text]
  • Potential Toxic Algal Incident in the Orange River Northern Cape 2000
    Potentially Toxic Algal Incident in the Orange River, Northern Cape, 2000 by C.E. van Ginkel & B. Conradie IWQS & NC Region • I bEPARTMENT OF WATER AFFAIRS AND FORESTRY I 0 -,_. TITLE: POTENTIALLY TOXIC ALGAL INCIDENT IN THE ORANGE RIVER, NORTHERN CAPE, 2000. REPORT NUMBER: N/D801/12/DEQ/0800 PROJECT: Eutrophication Project STATUS OF REPORT: Final DATE: July 2001 This report should be cited as: Van Ginkel, C.E. and B. Conradie (2001). Potential toxic algal incident in the Orange River, Northern Cape, 2000. Draft Report No. N/D801/12/DEQ/0800. Institute for Water Quality Studies, Department of Water Affairs and Forestry. Pretoria. ACKNOWLEDGEMENTS 1. All the external stakeholders who assisted in collecting, storing and transporting samples. These include (not in any order of priority): • Mr Jaco Goussard (JCG Water Treatment) • Mr Gert Meiring (Upington Municipality) • Mr Gawie Moon (Council for Geo Science) • Personnel at the Pelladrift and Namakwa Water Boards • Personnel of the Trans Hex Limited mining company at Reuning and Baken • Personnel of the Alexkor Limited mining company (at the mine and on the farms) • Personnel of Global Diamond Resources at Grasdrift • Personnel of the Richtersveld National Park • Mrs Bettie Nieuwouldt, Richtersveld Farmers' Union • Springbok Lodge and Restaurant perspnnel • Northern Cape Nature Conservation Services • Wilna Barkhuizen at the Vioolsdrift Irrigation Board 2. Personnel of the Department of Water Affairs and Forestry (DWAF) who contributed beyond their normal duties to make the task possible, including: • Personnel from the Institute for Water Quality Studies (IWQS): DWAF who visited Upington promptly to supply preservatives and sampling equipment to the office and assisted the Upington office in numerous logistical arrangements as well as providing expertise as member of the National Toxic Algal Forum (Mrs Carin van Ginkel), laboratory personnel (Eisabe Truter, Chris Carelson, Doris le Roux) and the technical team {Annelise Gerber) who assisted with data collection, analysis and reporting.
    [Show full text]
  • 27 the Alluvial Diamond Deposits of The
    TR ClI- 27 THE ALLUVIAL DIAMOND DEPOSITS OF THE LOWER VAAL RIVER BETWEEN BARKLY WEST AND THE VAAL-HARTS CONFLUENCE IN THE NORTHERN CAPE PROVINCE, SOUTH AFRICA By FABRICE GILBERT MATHEYS B.Sc. (Hons) Thesis snbmitted in partial fnlfllment of the requirements for the degree of MASTER OF SCIENCE Department of Geology . Rhodes University Grahamstown DECEMBER 1990 ABSTRACT The alluvial diamond deposits along the Vaal River, between Barkly West and the Vaal-Harts confluence, have been worked for more than one century by thousands of private diggers. The diamonds are recovered from two sedimentary units of Cenozoic age, the Older Gravels and the Younger Gravels. These rest on a basement of Ventersdorp Supergroup andesites and Karoo Sequence sediments, which have been intruded by Cretaceous kimberlites. The gravels are, in turn, overlain by the Riverton Formation and the Hutton Sand. On a large scale, tectonic setting, geomorphology and palaeoclimate have played a major role in the formation of diamondiferous placers in the araa under investigation. A study of the sedimentology of the Younger Gravels was carried out with the aim of acquiring an understanding of tha processes responsible for the economic concentration of high quality diamonds. An investigation of facies assemblages, clast composition, clast size, external geometry, particle morphology and palaeocurrent directions led to the conclusion that the Younger Gravels were deposited in a proximal braided stream environment during high discharge. A small-scale experiment was carried out to test the efficiency of different sedimentological trap sites in concentrating kimberlite indicator minerals. The results show that the concentration of indicator minerals is dependent o~the size fraction choosen, bed roughness and gravel calibre.
    [Show full text]
  • THE IMPACTS of SMALL SCALE ARTISANAL DIAMOND MINING on the ENVIRONMENT By
    THE IMPACTS OF SMALL SCALE ARTISANAL DIAMOND MINING ON THE ENVIRONMENT by MELANIE NAIDOO-VERMAAK MINI DISSERTATION Submitted in partial fulfillment of the requirements for the degree MAGISTER SCIENTIAE ENGINEERING in ENVIRONMENTAL MANAGEMENT in the FACULTY OF SCIENCE at the UNIVERSITY OF JOHANNESBURG Supervisor: Dr JM Meeuwis October 2006 i ABSTRACT This mini-dissertation establishes the extent to which small scale artisanal diamond mining impacts on the environment. There has, in the past, been research undertaken specifically on the water related impacts of small scale artisanal diamond mining. This study however, looks at the environment holistically, and gauges the total degradation to the receiving environment. Small scale artisanal diamond mining is considered to be a major contributor to the local economy and improved quality of life for the communities participating in this mining and is being actively supported through the National minerals and mining policies. It is for this reason that it was deemed imperative to understand the nature of the mining and the associated environmental impacts so that the outcome of this report could be used to inform decision makers when considering the licencing and management of artisanal diamond mining operations. In order to achieve the aim of the study, a literature review needed to be conducted focusing on the nature of small scale diamond mining operations, its influence on the social and economic spheres and the known environmental damage induced by such mining activities. However, in order to internalize the impacts, the literature review also drew a comparison with large scale artisanal diamond mining. The problems identified at the four sample sites were evaluated through the OWL Risk Assessment method to gauge the high risks and major impacts.
    [Show full text]
  • 1 Jbs21 (Ewr 17: Lloyds Weir (Harts River) – Osaeh 29.1)
    1 JBS21 (EWR 17: LLOYDS WEIR (HARTS RIVER) – OSAEH 29.1) The information is summarised from DWA (2009c,d; 2010c). The Harts River system is in the C3 drainage region of South Africa and its source is near the town of Lichtenburg in the North West Province, although the larger part of the catchment is situated in the Northern Cape Province. The Harts River flows in a south- westerly direction via Barberspan, the Taung and Spitskop dams, after which it flows into the Vaal River near Delportshoop. 1.1 SITE DESCRIPTION EWR 17 falls within MRU Harts C which includes Wentzel Dam which is delineated as a unit. The dam supports the domestic water use in Wentzel and the yield of the dam is fully utilised. The EWR site is in close proximity to OSAEH 29.1. This site was not assessed during the October 2010 field trip and the results of the EWR assessment are summarised below. EWR 17 is situated downstream of Spitskop Dam in the Harts River. The banks are composed of bedrock, and the channel is incised. Paired low benches occur but terraces are absent. Some paths in the upper and lower riparian zones has caused erosion. Fish habitat is well represented at site but flow modification by Spitskop Dam a short distance upstream of site is expected to result in unnatural habitat fluctuation. The weir directly upstream of site may result in unnaturally high abundance of species during migrations. Macroinvertebrate habitat is good with limited aquatic vegetation and mud habitats. Location EWR 17 Lloyds weir Altitude 1114 m Longitude 24.30305 Latitude -28.37694 Southern/Central Kalahari/Ghaap plateau EcoRegion Quaternary catchment C33C 29.02; 30.01 Water Management Area Lower Vaal Geomorphological zone Lower Foothills EWR 17, Lloyds weir.
    [Show full text]
  • Diversity and Characteristics of Yeasts in Water Sources of the North West Province
    Diversity and characteristics of yeasts in water sources of the North West Province By Deidré Alima Bregené Van Wyk (B.Sc Honours) Submitted in partial fulfilment of the requirements for the degree Master of Science in Environmental Science, in the School of Biological Science, Faculty of Natural Science, North-West University: Potchefstroom Campus Supervisor: Prof. C.C. Bezuidenhout Co-supervisor: Mr. O.H.J. Rhode Date Submitted: November 2012 ABSTRACT Yeasts form an important part of many ecosystems and significantly contribute to biodiversity. However, yeast biodiversity in the North West Province remains largely unexplored. The aim of this study was to determine the diversity and characteristics of yeasts from water sources in the North West Province, South Africa. Samples were collected over a two year period and included three rivers, a spruit and an inland lake. Temperature, pH, and electrical conductivity (EC) were measured on site using a multi- 2- probe. Nitrate (NO3-N), nitrite (NO2-N) and phosphate (PO4 ) levels were determined in the laboratory using Hatch kits and equipment. The pH ranged from 7.2 to 9.2. Elevated EC levels (36-70 mS) were detected especially at the Harts River and Barberspan (38-165 mS) sites. Physico-chemical parameter levels were higher during the cold dry sampling period compared to the warm rainy sampling period. Levels and diversity of yeasts were determined using the membrane filtration method. The highest level of yeasts was detected in the Mooi River and Schoonspruit during 2010 and 2011 sampling periods. Pigmented and non-pigmented yeasts were enumerated from all samples. Over the two year period the highest number of pigmented yeasts was detected in the Schoonspruit samples.
    [Show full text]
  • Frances Baard District Municipality: Proposed Nkandla Extension 2 Township Establishment, Erf 258 Nkandla, Hartswater, Northern Cape Province
    FRANCES BAARD DISTRICT MUNICIPALITY: PROPOSED NKANDLA EXTENSION 2 TOWNSHIP ESTABLISHMENT, ERF 258 NKANDLA, HARTSWATER, NORTHERN CAPE PROVINCE Archaeological Impact Assessment Prepared for: Frances Baard District Municipality Prepared by: Exigo Sustainability -i- Firefly Investments 224: Platinum Solar Park Project Archaeological Impact Assessment Report ARCHAEOLOGICAL IMPACT ASSESSMENT (AIA) OF AREAS DEMARACTED FOR THE PROPOSED NKANDLA EXTENSION 2 TOWNSHIP ESTABLISHMENT ON A PORTION OF ERF 258 NKANDLA, FRANCES BAARD DISTRICT MUNICIPALITY, NORTHERN CAPE PROVINCE Conducted on behalf of: Frances Baard District Municipality Exigo Sustainability Compiled by: Nelius Kruger (BA, BA Hons. Archaeology Pret.) Reviewed by: Freddy Netshivhodza (Frances Baard District Municipality) Document History Document Version 1 (Draft) – 25 March 2016 Document Version 2 (Final) – 31 March 2016 -i- Firefly Investments 224: Platinum Solar Park Project Archaeological Impact Assessment Report Although Exigo Sustainability exercises due care and diligence in rendering services and preparing documents, Exigo Sustainability accepts no liability, and the client, by receiving this document, indemnifies Exigo Sustainability and its directors, managers, agents and employees against all actions, claims, demands, losses, liabilities, costs, damages and expenses arising from or in connection with services rendered, directly or indirectly by Exigo Sustainability and by the use of the information contained in this document. This document contains confidential and proprietary information equally shared between Exigo Sustainability. and Frances Baard District Municipality, and is protected by copyright in favour of these companies and may not be reproduced, or used without the written consent of these companies, which has been obtained beforehand. This document is prepared exclusively for Frances Baard District Municipality and is subject to all confidentiality, copyright and trade secrets, rules, intellectual property law and practices of South Africa.
    [Show full text]