Erand Gardens Ext 70 (Protea Gardens Erf 765), Gauteng Province
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REPORT WETLAND HYDROPEDOLOGY IDENTIFICATION AND MANAGEMENT REPORT: ERAND GARDENS EXT 70 (PROTEA GARDENS ERF 765), GAUTENG PROVINCE 9 March, 2018 Compiled by: J.H. van der Waals (PhD Soil Science, Pr.Sci.Nat.) Registered with the South African Council for Natural Scientific Professions (Registration number: 400106/08) Member of: Soil Science Society of South Africa (SSSSA) Accredited member of: South African Soil Surveyors Organisation (SASSO) i Declaration I, Johan Hilgard van der Waals, declare that: • I act as the independent specialist in this application • I will perform the work relating to the application in an objective manner, even if this results in views and findings that are not favourable to the applicant • I declare that there are no circumstances that may compromise my objectivity in performing such work; • I have expertise in conducting the specialist report relevant to this application, including knowledge of the Act, regulations and any guidelines that have relevance to the proposed activity; • I will comply with the Act, regulations and all other applicable legislation; • I have no, and will not engage in, conflicting interests in the undertaking of the activity; • I undertake to disclose to the applicant and the competent authority all material information in my possession that reasonably has or may have the potential of influencing - any decision to be taken with respect to the application by the competent authority; and - the objectivity of any report, plan or document to be prepared by myself for submission to the competent authority; • all the particulars furnished by me in this form are true and correct; and • I realise that a false declaration is an offence in terms of Regulation 71 and is punishable in terms of Section 24F of the Act. J.H. VAN DER WAALS ii TABLE OF CONTENTS 1. INTRODUCTION ..................................................................................................................... 1 1.1 Terms of Reference .......................................................................................................... 1 1.2 Aim of this Report ............................................................................................................. 1 1.3 Disclaimer ......................................................................................................................... 1 1.4 Methodology ..................................................................................................................... 2 1.5 Relevant Reports .............................................................................................................. 2 2. SITE LOCALITY AND DESCRIPTION .................................................................................... 3 2.1 Survey Area Boundary ...................................................................................................... 3 2.2 Land Type Data ................................................................................................................ 3 2.3 Topography ...................................................................................................................... 3 3. PROBLEM STATEMENT ........................................................................................................ 3 4. STATUTORY CONTEXT ........................................................................................................ 8 4.1. Wetlands ........................................................................................................................... 8 4.1.1 Wetland Definition ......................................................................................................... 8 4.1.2 Disaggregation of the Wetland Definition ....................................................................... 8 4.2 Watercourse Definition ...................................................................................................... 9 4.3 The Wetland Delineation Guidelines ................................................................................. 9 4.4 The Resource Directed Measures for Protection of Water Resources ............................ 10 4.4.1 The Resource Directed Measures for Protection of Water Resources: Volume 4: Wetland Ecosystems. ............................................................................................................ 11 4.4.2 The Resource Directed Measures for Protection of Water Resources: Generic Section “A” for Specialist Manuals – Water Resource Protection Policy Implementation Process ................................................................................................................................ 11 4.4.3 The Resource Directed Measures for Protection of Water Resources: Appendix W1 (Ecoregional Typing for Wetland Ecosystems) ...................................................................... 12 4.4.4 The Resource Directed Measures for Protection of Water Resources: Appendix W4 IER (Floodplain Wetlands) Present Ecological Status (PES) Method .................................... 12 4.4.5 The Resource Directed Measures for Protection of Water Resources: Appendix W5 IER (Floodplain Wetlands) Determining the Ecological Importance and Sensitivity (EIS) and the Ecological Management Class (EMC) ............................................................................. 16 4.5 Water Use Licence Applications and Risk Assessment ................................................... 17 4.6 Lack of Clarity on Reference State and Man-Made Wetlands ......................................... 17 4.7 The City of Johannesburg (CoJ) Wetland Layer .............................................................. 18 4.8 Summary and Proposed Approach ................................................................................. 19 5. CHALLENGES REGARDING WETLAND DELINEATION AND POLLUTION RISK ASSESSMENTS ON THE HALFWAY HOUSE GRANITE DOME ................................................. 20 5.1 Wetland Drivers and Ecological Responses .................................................................... 20 5.2 Soil as a Tool for Landscape Context and Hydrological Driver Description ..................... 22 5.3 Pedogenesis ................................................................................................................... 23 5.4 Water Movement in the Soil Profile ................................................................................. 24 5.5 Water Movement in the Landscape ................................................................................. 27 iii 5.6 The Catena Concept ....................................................................................................... 30 5.7 The Halfway House Granite Dome Catena ..................................................................... 31 5.8 Convex Versus Concave Landscapes in the Halfway House Granite Catena ................. 32 5.9 Implications for Wetland Delineation and Application of the Guidelines .......................... 33 5.10 Implications for Wetland Conservation in Urban Environments.................................... 34 5.11 Implications for Water Movement in the Landscape (Conceptual) ............................... 37 5.12 Implications for Downstream Wetlands, Watercourses and Landscapes ..................... 38 5.13 Soil Erosion on the Halfway House Granite Dome....................................................... 39 5.14 Sustainable Urban Drainage Considerations ............................................................... 42 5.14.1 SuDS Philosophy and Options ................................................................................. 42 5.14.2 SuDS – Practical Considerations in the HHGD Area ................................................ 42 6. METHOD OF WETLAND INVESTIGATION AND IDENTIFICATION ..................................... 45 6.1 Wetland Context Determination ...................................................................................... 45 6.2. Aerial Photograph Interpretation ..................................................................................... 45 6.3 Terrain Unit Indicator ...................................................................................................... 45 6.4 Soil Form and Soil Wetness Indicators ........................................................................... 45 6.5 Vegetation Indicator ........................................................................................................ 45 6.6 Artificial Modifiers and Altered Hydrological Drivers ........................................................ 46 7. WETLAND INVESTIGATION RESULTS AND DISCUSSION ................................................ 46 7.1 Wetland Context ............................................................................................................. 46 7.2 Aerial Photograph Interpretation ..................................................................................... 46 7.2.1 Historical Aerial Photographs ................................................................................... 46 7.2.2 Google Earth Images ............................................................................................... 50 7.3 Terrain Unit Indicator ...................................................................................................... 54 7.4 Soil Form and Soil Wetness Indicators (Site Survey) ...................................................... 55 7.5 Artificial Modifiers and Altered Hydrological Drivers .......................................................