Classification of Significant Water Resources in the Upper Middle and Lower Vaal WMAs WR Ana lys is Report Classification of Significant Water Resources (River, Wetlands, Groundwater and Lakes) in the Upper, Middle and Lower Vaal Water Management Areas (WMA) 8,9,10 WATER RESOURCE ANALYSIS REPORT: Report number: RDM/WMA8,9,10/00/CON/CLA/0411 Inception Report May 2012 (FINAL) Copyright reserved No part of this publication may be reproduced in any manner without full acknowledgement of the source REFERENCE This report is to be referred to in bibliographies as: Department of Water Affairs, South Africa, September 2011. Classification of Significant Water Resources (River, Wetlands, Groundwater and Lakes) in the Upper, Middle and Lower Vaal Water Management Areas (WMA) 8, 9, 10: Water Resource Analysis Report Prepared by: WRP Consulting Engineers (Pty) Ltd in association with DMM Development Consultants CC, Rivers for Africa eFlows Consulting (Pty) Ltd, Conningarth Economists, Koekemoer Aquatic Services and Zitholele Consulting (Pty) Ltd. Report No. RDM/WMA8,9,10/00/CON/CLA/0411 Water Resource Analysis Report May 2012 i Classification of Significant Water Resources in the Upper Middle and Lower Vaal WMAs WR Ana lys is Report DOCUMENT INDEX Reports as part of this project (report status as in July 2011): Index number RDM Report number Report title Classification of Significant Water Resources (River, Wetlands, 1.1 RDM/WMA8,9,10/00/CON/CLA/0111 Groundwater and Lakes) in the Upper, Middle and Lower Vaal Water Management Areas (WMA) 8,9,10, Inception Report Classification of Significant Water Resources (River, Wetlands, 1.2 RDM/WMA8,9,10/00/CON/CLA/0211 Groundwater and Lakes) in the Upper, Middle and Lower Vaal Water Management Areas (WMA) 8,9,10, Status Quo Report Classification of Significant Water Resources (River, Wetlands, Groundwater and Lakes) in the Upper, Middle and Lower Vaal Water 1.3 RDM/WMA8,9,10/00/CON/CLA/0311 Management Areas (WMA) 8,9,10, Quantification of the Ecological Water Requirement Report Classification of Significant Water Resources (River, Wetlands, Groundwater and Lakes) in the Upper, Middle and Lower Vaal 1.4 RDM/WMA8,9,10/00/CON/CLA/0411 Water Management Areas (WMA) 8,9,10, Water Resource Analysis Report Bold indicates this report. Water Resource Analysis Report May 2012 ii Classification of Significant Water Resources in the Upper Middle and Lower Vaal WMAs WR Ana lys is Report Title: Water Resource Analysis Report Authors: HS Swart, CJ Seago, PG van Rooyen Study Name: Classification of Significant Water Resources (River, Wetlands, Groundwater and Lakes) in the Upper, Middle and Lower Vaal Water Management Areas (WMA) 8,9,10 DWA Report No: RDM/WMA8,9,10/00/CON/CLA/0411 Status of Report: FINAL First Issue: March 2012 Final Issue: May 2012 Consultants: WRP Consulting Engineers (Pty) Ltd in association with DMM Development Consultants CC, Rivers for Africa eFlows Consulting (Pty) Ltd, Conningarth Economists, Koekemoer Aquatic Services and Zitholele Consulting (Pty) Ltd. Approved for the Consultants by: ………………………………………………… PG van Rooyen Study Leader DEPARTMENT OF WATER AFFAIRS Directorate: Water Resource Classification Approved for DWA by: ………………………………………………… N Mohapi Chief Director: Water Ecosystem Water Resource Analysis Report May 2012 iii Classification of Significant Water Resources in the Upper Middle and Lower Vaal WMAs WR Ana lys is Report MANAGEMENT AND STEERING COMMITTEES Project Management Committee Shane Naidoo Department of Water Affairs Director: Water Resource Classification Tovhowani Nyamande Department of Water Affairs Project Manager Lawrence Mulangaphuma Department of Water Affairs Project Co-ordinator Project Team Pieter van Rooyen WRP Consulting Engineers (Study Leader) Susan Swart WRP Consulting Engineers Andre Joubert Zitholele Consulting Delana Louw Rivers for Africa eFlow William Mullins Conningarth Economists Riekie Cloete Conningarth Economists Darius Mnguni DMM Development Consultants Shael Koekemoer Koekemoer Aquatic Services Patsy Scherman Scherman Colloty & Associates Piet Kotze Clean Stream James MacKenzie MacKenzie Ecological and Development Services Rob Palmer Nepid Consultants Mark Rountree Fluvius Greg Hugggins Nomad Consulting Members of Project Steering Committee (Refer to Appendix T for list of members) Water Resource Analysis Report May 2012 iv Classification of Significant Water Resources in the Upper Middle and Lower Vaal WMAs WR Ana lys is Report Classification of Significant Water Resources (River, Wetlands, Groundwater and Lakes) in the Upper, Middle and Lower Vaal Water Management Areas (WMA) 8,9,10 Water Resource Analysis Report Executive Summary 1. BACKGROUND This study entitled “Classification of Significant Water Resources (River, Wetlands, Groundwater and Lakes) in the Upper, Middle and Lower Vaal Water Management Areas (WMA) 8,9,10” was commissioned by the Chief Directorate Resource Directed Measures (RDM) of the Department of Water Affairs (DWA) in October 2010. The ultimate purpose of the study is the implementation of the Water Resource Classification System (WRCS) in the above-mentioned three Vaal WMAs according to the 7 step process proposed by the WRCS (DWAF, 2007) as described in Figure D-1 of Appendix D. The main objective of this document is to describe the assumptions and database used for the water resource analyses undertaken for this study as part of Steps 5 and 6 of the WRCS (see Figure D-1) and to summarise the results presented to the Ecological and Socio-Economic Team for further evaluation. 2. STUDY AREA The core of the study area consists of the Upper, Middle and Lower Vaal River Water Management Areas (WMAs), however, due to the numerous inter-basin transfers that link this core area with other WMAs, the water resource assessments had to be undertaken in the context of the Integrated Vaal River System (IVRS) which also includes portions of the Komati, Usutu, Thukela, Senqu River (located in Lesotho) and Upper Orange (Riet-Modder River) catchments. The study area, therefore, comprises of the water resource and bulk supply systems of the entire Integrated Vaal River System as shown in Figure A-1 of Appendix A. A detailed description of the IVRS and its operation is provided in Section 2. It is important to note that the Riet-Modder catchment, which forms part of the Orange River WMA, is not included in the study area. Water Resource Analysis Report May 2012 v Classification of Significant Water Resources in the Upper Middle and Lower Vaal WMAs WR Ana lys is Report 3. DECISION SUPPORT SYSTEM FOR IVRS Due to the highly developed nature of the IVRS and the various inter-basin transfers that exist in the system, operating rules were developed that regulate when and how much water is transferred. The management and implementation of these operating rules (which include the dilution of the TDS concentration downstream of Vaal Barrage) are undertaken by the application of the Water Resource Planning Model (WRPM). The WRPM was subsequently used as the Decision Support System (DSS) for this study. The WRPM system schematics are included in Appendix C. A low confidence high resolution network configuration of the Water Resource Yield Model (WRYM) was used to undertake a cursory quantitative evaluation of the water availability (and consequential implications) at small catchment scale based on land use data from the Validation and Verification study that is currently being undertaken in the three Vaal River WMAs. 4. HYDROLOGICAL DATABASE The WRPM configuration of the IVRS includes the hydrological database resulting from the Vaal River System Analysis Update (VRSAU) Study (DWAF, 1999). The VRSAU hydrology covers the period October 1920 to September 1995 (i.e. a period of 75 years). It is important to note that the hydrological analyses of the VRSAU study were not necessarily undertaken at quaternary catchment level as the focus was on the most representative modelling of relevant sub-catchments. The methodology adopted for the disaggregation of lumped hydrology is described in Section 4.4. 5. WATER BODIES A large number of reservoirs form part of the Integrated Vaal River System. These water bodies include major impoundments such as Heyshope, Zaaihoek, Grootdraai, Woodstock, Sterkfontein, Katse, Mohale, Vaal and Bloemhof dams as well as a large number of smaller dams which are mainly used for local municipal water supply, rural water supply, irrigation, livestock and game farming. Impoundments are discussed in Section 5 and information on major dams is summarised in Table E-9 of Appendix E. 6. WATER REQUIREMENT AND RETURN FLOW PROJECTIONS The WRPM database includes growing water requirements up to the year 2030. Since the Integrated Vaal River System (IVRS) is analysed on an annual basis, the water requirement projections of the major bulk water suppliers (Rand Water, Midvaal Water Company and Sedibeng Water), the strategic water user Eskom, as well as large industries such as Sasol and Mittal Steel (previously known as Iscor), are also updated annually. The most recent water requirement projections of the above-mentioned users (revised as part of the 2011/2012 Annual Operating Analysis) were used for the WRPM scenario analyses undertaken for this study. Two levels of catchment development were considered: Present Day (2011) and a Future (2020) condition. The water requirements and return flows representative of these two development conditions are summarised in Table 6-6 of Section 6.7 and details thereof are provided in Appendix F. Water Resource Analysis Report May 2012 vi Classification of Significant Water Resources in the Upper Middle and Lower Vaal WMAs WR Ana lys is Report 7. INTEGRATED UNITS OF ANALYS IS AND BIOPHYSICAL NODES Considerations for the identification and selection of the Integrated Units of Analysis (IUAs) are described in the Status Quo Report (DWA, 2011b) compiled as part of this study. The identified IUAs for the three Vaal Water Management Areas are shown in Figures B-1, B-2 and B-3 of Appendix B and listed in Table 7-1. The key biophysical nodes are the Ecological Water Requirement (EWR) sites and the selection process of these sites is documented in the recent Reserve studies (DWAF, 2008e; DWAF 2009a and b).