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Wetland and Aquatic Screening Studies

The screening of a proposed development site should ideally be conducted prior to the draft site layout being finalised. This is to ensure that all potential sensitive areas within the proposed site are identified to inform the overall site layout, and thus reduce the risk of impact and any potential delays that may otherwise be evident during the Environmental Authorisation (EA) and Water Use License Application (WULA) processes. At present, the newly required Department of Environment, Forestry and Fisheries (DEFF) environmental screening tool report, which must be generated for every proposed development, provides an initial desktop sensitivity rating of a proposed site, including the aquatic and wetland sensitivity of the systems that may be situated within the boundary. The desktop sensitivity will be displayed as low, medium or very high based on the SANBI environmental data input relevant to the proposed site. Every site, regardless of it being identified as low sensitivity at a desktop level, must undergo an initial site sensitivity verification by an Environmental Assessment Practitioner (EAP), or preferably a SACNASP registered specialist with expertise in the relevant field (i.e. wetland and aquatic ecology). The outcome of the initial site sensitivity verification must be recorded in the form of a report that must, in terms of wetland and aquatic resources; 1) Confirm or dispute the current on-site sensitivity of watercourses against the DEFF screening report results, 2) Contain a motivation and evidence (e.g. photographs) of either the verified or different watercourse sensitivity and 3) Be submitted with the relevant DEFF screening report in accordance with the EIA Regulations (DEA, 2017).

 

The abovementioned initial site sensitivity verification essentially constitutes as the wetland and aquatic screening. The screening process will involve ENVASS conducting a desktop study of the site from a freshwater resources perspective and a desktop delineation of all watercourse within the boundary. Thereafter, a once-off site visit will be undertaken by a suitably qualified, professionally registered SACNASP natural scientist to ground truth the watercourse delineated at a desktop level. The Department of Water Affairs and Forestry (DWAF) “A practical field procedure for identification and delineation of wetland and riparian areas” will be implemented on-site to delineate all watercourse within the proposed site. The data obtained during this process, as well as a Wetland and Aquatic Biodiversity Compliance Statement, will be presented within a formal Screening Report that will be submitted to the client for comment and subsequent finalisation if all is deemed to be in order. The screening report can be used to inform the site layout and design of a proposed development, and should be submitted to the relevant DEFF and/or DWS officials to guide the EIA and WULA processes.

Watercourse (wetland and rivers) Impact and Baseline Assessment

In instances where a proposed development is considered to be of a high or medium risk of impacting on a watercourse (wetlands and rivers), a full impact assessment may be required. Other situations where a full watercourse assessment may be required would be if a baseline study is requested for a proposed site. This will essentially form the initial results against which all future studies within the wetland and aquatic field can be compared to, to determine whether positive or negative changes have occurred to the relevant watercourses. When conducting watercourse impact assessments associated with the WULA and EA processes, a 500 Metre (m) and 100 m assessment radius around all wetlands and rivers, respectively, will be adopted during the study. This constitutes as the regulatory area associated with each at-risk wetland or river and will thus be used as the study area within the assessment (DWS; GN509, 2016).

 

The process of conducting a full watercourse impact assessment will involve the implementation of the following steps and associated methodologies and/or guidelines:

  • A desktop study will be undertaken, in which all the available data (e.g. government records, spatial datasets and previous studies) pertaining to the study area will be sourced and subsequently utilised to determine the theoretical importance and sensitivity of the freshwater ecosystems within the proposed site. The relevant datasets will be mapped using GIS software and presented in relation to the study area. At this stage, the watercourses within the study area will be delineated at a desktop level using available aerial imagery, contour and river line data, as well as national delineated wetland information (e.g. National Wetland Inventory 5 and National Freshwater Ecosystem Priority Area (NFEPA) data).
  • A field survey of the watercourses situated within the study area associated with the proposed development will then be undertaken. The primary objectives of the field survey will be to; 1) verify and accurately delineate the watercourses that were deemed to be at high or medium risk of being impacted on by the proposed development, 2) record the current land uses within the surrounding catchment areas and identify disturbances and areas of degradation in relation to the desktop reference, or natural state, 3) conduct an in-depth analysis of the Present Ecological State (PES) of the at-risk watercourses and determine the potential of, and level to which, the systems supply valuable Ecosystem Services (ESS) to the surrounding natural and anthropogenic environments. The wetland delineation will be conducted in accordance with the Department of Water Affairs and Forestry (DWAF) “A practical field procedure for identification and delineation of wetland and riparian areas” (DWAF, 2005-08).
  • Assessment of the current integrity of the at-risk watercourses and presentation of the PES score using the relevant legislated and best-practice methodologies and guidelines (e.g. WET-Health (MacFarlane et al., 2009) and Index of Habitat Integrity (IHI) (Kleynhans et al., 2008)).
  • Assessment of the Ecological Importance and Sensitivity (EIS) of the at-risk watercourses using the relevant legislated and best-practice methodologies and guidelines (e.g. WET-Ecoservices (Kotze et al., 2007) and River EIS (Rountree, 2013)).
  • Determine the Recommended Ecological State (REC), or Recommended Management Objective (RMO) of the at-risk watercourses using the calculated PES score and EIS ratings in correlation with the DWAF (2007) table.
  • Conduct a detailed impact assessment of the perceived direct, indirect and cumulative impacts that may be associated with the proposed development in accordance with Section 31(2)(i) of the National Environmental Management Act (Act no. 107 of 1998) (NEMA).
  • Formulation of necessary avoidance, mitigation and/or rehabilitation measures that should be implemented to reduce the impact of the proposed development on the receiving aquatic environment.
  • Present an impact statement and the specialist’s reasonable opinion as to whether or not the proposed development should continue within the preferred alternative, and what conditions may be required to ensure a ‘least impact’ scenario becoming a reality in the post-development phase.

Wetland Delineation and Classification

The National Water Act (Act no. 36 of 1998) defines a wetland as “land which is transitional between terrestrial and aquatic systems, where the water table is usually at, or near to the surface, or the land is periodically covered with shallow water and which land under normal circumstances supports, or would support, vegetation adapted to life in saturated soil”. In line with this definition, and the Department of Water and Sanitation General Notice (GN) 509 of 2016, the outer boundary of a wetland or pan is therefore the outer temporary zone (i.e. the boundary between the temporary wetness zone and terrestrial zone). This is delineated in-field through the implementation of the Department of Water Affairs and Forestry (DWAF) “A practical field procedure for identification and delineation of wetland and riparian areas” (DWAF, 2005-08). According to the South African Society, a wetland delineation includes; confirmation of the presence (and size) of a wetland and an approximate determination of the outermost boundary of a wetland. Additionally, a wetland delineated should result in; 1) a wetland boundary indicated on a map and where necessary verified in the field by means of a survey, 2) a map that clearly indicates data collection points (i.e. soil auger sites) and the boundaries of the delineated wetland using available terrain and aerial imagery information and 3) a report that explains how the boundary was determined.

 

Subsequent to undertaking and finalising the wetland delineation, the relevant wetland systems need to be classified into Hydrogeomorphic (HGM) Units. HGM units are wetlands, or portions of wetlands, that have very similar hydrological and geomorphological characteristics based on; 1) geomorphic setting, 2) water source and 3) hydrodynamics. This is achieved by implementing the legislated methodology by Ollis et al. (2013), titled ‘Classification system for wetland and other aquatic ecosystems in South Africa’. All of the above would be presented in a Wetland Delineation report that will be submitted to the client for comment and subsequent finalisation if all is deemed to be in order.

Aquatic SASS5 Biomonitoring

Biomonitoring is defined as the act of observing and assessing the state and ongoing changes in ecosystems, components of biodiversity and landscape, including the types of natural habitats, populations and species (Bondaruk et al., 2015). The periodic implementation of biomonitoring using the South African Scoring System Version 5 (SASS5) methodology (Dickens & Graham, 2002), within low-to-medium flow rivers and NOT wetlands, impoundments or other lentic habitats, is considered the best rapid aquatic macroinvertebrate assessment within South Africa at present. The SASS5 methodology should not be implemented in isolation, and should be supplemented by at least the assessment of aquatic habitat integrity and availability within the relevant assessment reach via implementation of the Index of Habitat Integrity (IHI) (Kleynhans et al., 2013) and Integrated Habitat Assessment System (IHAS) (Ollis et al., 2006) tools, respectively. Additional tools such as the Fish Response Assessment Index (FRAI) (Kleynhans et al., 2007), Riparian Vegetation Response Assessment Index (VEGRAI) (Kleynhans et al., 2007) and Macroinvertebrate Response Assessment Index (MIRAI) (Thirion, 2007) should also be considered when conducting an in-depth aquatic biomonitoring study.

 

All of the above mentioned methodologies and tools are frequently implemented by the ENVASS in-house specialists during routine and once-off aquatic biomonitoring studies, either applicable to Water Use License (WUL) conditions, or the baseline Environmental Impact Assessment (EIA) process. The ENVASS aquatic specialists whom conduct said studies have been accredited to do so by the national Department of Water and Sanitation (DWS) and are professionally registered with SACNASP, and thus are considered to be compliant in terms of current environmental legislation.

Conceptual Rehabilitation Management and Monitoring Programme

Subsequent to a proposed development being constructed, or an activity such as a mine being established it may be evident that there will be considerable negative impact on the receiving aquatic environment that should be remediated. This is usually determined during the initial Environmental Impact Assessment (EIA) phase of a project when specialist studies and impact assessments are conducted. The outcomes of which, and subsequent to the implementation of the Department of Environmental Affairs (2013) mitigation hierarchy, may present that rehabilitation of impacts will be required. The mitigation hierarchy aims to first avoid negative impact, but if this is not possible the next tier is to minimise these impacts. Effective minimisation can eliminate some impacts and reduce others allowing for sustainability targets to be met. The next consideration is restoration, or rehabilitation and takes place where minimisation efforts have failed to reach the required remediation target. At this stage, the exact quantity of functional aquatic habitat (hectare equivalents) that may be lost as a result of a proposed development, or activity must be calculated. This will inform the level of rehabilitation that should be considered for the project. Based on the perceived loss of direct area (Hectares) and the calculated hectare equivalent (ha equiv.) loss of functional aquatic habitat, appropriate mitigation and rehabilitation measures must be formulated in an effort to remediate the impacts within a specific hydrogeomorphic (HGM) Unit (i.e. wetland) and improve the state of the systems back to a near-natural, or pre-development condition. HGM unit-specific rehabilitation goals, objectives and targets are formulated to guide the required rehabilitation of each at-risk system. To calculate the theoretical effect of the proposed rehabilitation measures on the integrity of the at-risk HGM unit,  the ENVASS specialist will determine the pre- and post-development Present Ecological State (PES) scores, otherwise referred to as the integrity, of the aquatic habitat using legislated and best-practice methodologies and tools. In terms of wetland rehabilitation, this would be the WET-Health tool (MacFarlane et al., 2009), which uses three modules, namely; hydrology, geomorphology and vegetation, to calculate the PES score of a specific HGM unit. The pre- and post-development PES scores are then converted into a ha equiv. score, which is essentially a representation of the integrity of an HGM unit expressed as an area, to compare the pre and post-development scenarios. If the difference between the pre- and post-development ha equiv. scores is positive, it indicates that the theoretic rehabilitation measures proposed have the potential to remediate the perceived impacts of the proposed development, or activity on the receiving aquatic environment, and thus ensure a ‘no net loss of biodiversity’ in the post-development scenario. However, if the difference is recorded to be negative there will be a residual impact on the receiving aquatic environment, and further steps within the DEA mitigation hierarchy must be applied.

 

The ENVASS inhouse specialists have conducted numerous conceptual rehabilitation and monitoring programmes for various proposed development and activities and would be well-suited to assist with any rehabilitation needs your organisation may require.

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