WETLAND ASSESSMENT WESTERN MARGIN GAP WEST PROJECT, BOTHAVILLE, FREE STATE PROVINCE February 2018 Report prepared by: ENVIRONMENT RESEARCH CONSULTING ERC forms part of Benah Con cc cc registration no: 2005/044901/23 Postal address: PO Box 20640, Noordbrug, 2522 E-mail: [email protected] Mobile: 082 789 4669 Fax: 086 621 4843 Report Reference: SH2018-04 Report author: A.R. Götze ( Pr.Sci.Nat. ) Wetland Assessment: Western Margin Gap West TABLE OF CONTENTS 1 EXECUTIVE SUMMARY .......................................................................... 5 2 DECLARATION OF INDEPENDENCE AND SUMMARY OF EXPERTISE OF SPECIALIST INVESTIGATOR ................................................................. 11 2.1 Declaration of independence ............................................................ 11 2.2 Summary of expertise ....................................................................... 12 3 INTRODUCTION .................................................................................... 13 3.1 Scope of work ................................................................................... 14 3.2 Assumptions and Limitations ............................................................ 14 3.3 Methodology ..................................................................................... 15 3.4 Legislative and policy frameworks and definitions ............................ 16 4 RECEIVING ENVIRONMENT ................................................................. 20 4.1 General Description .......................................................................... 20 4.1.1 Highveld Alluvial Vegetation (AZa5) ........................................... 21 4.2 Surface hydrology ............................................................................. 22 4.3 Wetland vegetation ........................................................................... 25 4.4 Wetland soils .................................................................................... 28 4.4.1 Soil forms ................................................................................... 28 4.4.2 Soil wetness indicators ............................................................... 32 5 WETLAND DELINEATION ..................................................................... 34 6 PRESENT ECOLOGICAL STATUS (PES) ............................................. 38 6.1 PES methodology ............................................................................. 38 6.2 PES of wetlands in the study area .................................................... 40 7 ECOLOGICAL IMPORTANCE AND SENSITIVITY (EIS) ....................... 40 7.1 EIS methodology .............................................................................. 40 7.2 EIS of wetlands in the study area ..................................................... 43 8 WETLAND ECOSYSTEM SERVICES (ES) ............................................ 43 8.1 ES methodology ............................................................................... 43 8.2 ES of wetlands in the study area ...................................................... 44 9 CONSERVATION STATUS OF LOCAL ECOSYSTEMS........................ 45 10 HABITAT SENSITIVITY ....................................................................... 48 11 WETLAND REHABILITATION AND MANAGEMENT .......................... 53 11.1 Rehabilitation Principles ................................................................ 53 11.2 Rehabilitation Management ........................................................... 54 11.3 Rehabilitation Recommendations .................................................. 55 12 IMPACT ASSESSMENT ...................................................................... 56 12.1 Impact rating and mitigation........................................................... 56 12.2 Assessment of the no-go alternative ............................................. 58 12.3 Monitoring requirements ................................................................ 58 13 FINAL COMMENTS AND RECOMMENDATIONS .............................. 59 14 REFERENCES..................................................................................... 60 14.1 Literature sighted in this report ...................................................... 60 14.2 Other Literature and Field Guides Consulted ................................ 61 2 ERC: A.R. Götze – February 2018 – SH201804 Wetland Assessment: Western Margin Gap West LIST OF FIGURES Figure 1: Google earth image indicating the regional setting of the study area. ................................................................................................................ 13 Figure 2: Google earth image indicating the local setting of the study area. .. 14 Figure 3: Distribution of vegetation types in and around the study area according to Mucina and Rutherford (2006). ........................................... 20 Figure 4: Water Management Areas of Central and Northern South Africa. 22 Figure 5: Quaternary Catchment Areas of the study area (red polygon) and surroundings. .......................................................................................... 22 Figure 6: Image depicting the rivers, wetlands and other drainage lines recorded in the study area (red polygon). ............................................... 24 Figure 7: A section of the riparian zone on the banks of the Vals River. ....... 26 Figure 8: A section of riparian zone of the Vaal River. .................................. 26 Figure 9: A section of the unnamed drainage line and vegetation associated with the unchanneled valley bottom wetland along its course through the study area. .............................................................................................. 27 Figure 10: A seepage wetland in the study area. .......................................... 27 Figure 11: A dry man-made dam that is situated in a natural fold in the landscape of the northern part of the study area. ................................... 28 Figure 12: Katspruit soil form photographed in the permanent zone of a wetland. .................................................................................................. 29 Figure 13: Kroonstad soil form in a seasonal wetland zone. ......................... 30 Figure 14: Sepane soil form in the temporal zone of a drainage line. ........... 30 Figure 15: A Rensburg soil form in an eroded temporary zone. .................... 31 Figure 16: A Tukulu soil form in floodplain area. ........................................... 31 Figure 17: A Pinedene soil form in a temporary zone of a seepage wetland. 32 Figure 18: Low chroma grey matrix and sesquioxide mottles in the subsoil of a Sepane soil form. ................................................................................. 33 Figure 19: Low chroma grey matrix and sesquioxide mottles in the G-horizon of a Katspruit soil form. ........................................................................... 33 Figure 20: Delineated riparian zones and wetlands in the study area with 32 m buffer zones. ....................................................................................... 37 Figure 21: CBA and ESA image for the study area (red polygon) according to the 2015 Free State Biodiversity Plan. .................................................... 47 Figure 22: Wetland and riparian zone sensitivity in the study area. ............... 50 Figure 23: An Eskom power line situated in a temporary zone of an unchanneled drainage line wetland in the south of the study area. ........ 51 Figure 24: An inspection manhole for a water pipe line situated in the same drainage line as the power line in Figure 23. .......................................... 51 Figure 25: Total transformation of the riparian zone of the northern bank of a section of the Vaal River in the study area.............................................. 52 LIST OF TABLES Table 1: Soils and plant species associated with different wetness zones of un-channelled and seepage wetlands and riparian floodplain wetlands in the study area. ........................................................................................ 34 3 ERC: A.R. Götze – February 2018 – SH201804 Wetland Assessment: Western Margin Gap West Table 2: Soils and plant species associated with different wetness zones of man-made dams. .................................................................................... 35 Table 3: Soils and plant species associated with riparian zones in the study area. ....................................................................................................... 35 Table 4: Habitat integrity assessment criteria for palustrine wetlands (DWAF, 1999). ..................................................................................................... 38 Table 5: Scoring guidelines and relative confidence scores for the habitat integrity assessment for palustrine wetlands (DWAF, 1999)................... 39 Table 6: Category's assigned to the scores achieved in the wetland habitat assessment (Kleynhans, 1999; DWAF, 1999). ....................................... 40 Table 7: Broad PES values and categories of the wetland and riparian habitats in the study area. ....................................................................... 40 Table 8: Score sheet for determining EIS. ..................................................... 41 Table 9: Scoring guidelines and relative confidence scores for the habitat integrity assessment for palustrine wetlands (DWAF, 1999)................... 41 Table 10: Ecological