Updates to the WET-Health and WET-EcoServices suite of tools and how this will influence wetland assessments in South Africa

12th January 2023

Updates to the WET-Health and WET-EcoServices suite of tools and how this will influence wetland assessments in South Africa

(Showroom): The WET-Health and WET-EcoServices tools came into being out of a need to establish a baseline ecological condition and functional importance of wetlands prior to any potential impacts by proposed developments. According to Macfarlane et al (2007; 2020) ecological condition of Present Ecological State (PES) refers to:

‘The current state, compared to reference or best state, for the physical, chemical and biological characteristics of an ecosystem’.

In broad terms, functional importance refers to a wetland’s ability to provide ecosystem goods and services inclusive of the following (Macfarlane et al, 2008; 2020):

The WET-Health and WET-EcoServices tools were developed in 2007 as part of a comprehensive wetland management programme which was initiated by the Water Research Commission (WRC) in 2003 which focused on wetland rehabilitation, wetland health and integrity and sustainable of wetlands (Macfarlane et al, 2008). Both tools form part of the WET-Management series which provides a host of tools for the origins, assessment, management and rehabilitation of wetlands.

Key updates to the WET-Health and WET-EcoServices Tools WET-Health Version 2 (Macfarlane, Ollis and Kotze, 2020) WET-EcoServices Version 2 (Kotze, Macfarlane and Edwards, 2020)

Stronger emphasis on predetermined buffer, catchment and within wetland landcover classes. Inclusion of riparian areas as an assessment unit.

Provision of two desktop levels of assessment comprising of ‘Level 1A’ and ‘Level 1B’. The level 1A spreadsheet was designed for the assessment of several wetlands at a time.

 The supply and demand of the assessed services area assessed separately and the beneficiaries of the services are taken into consideration with particular emphasis on the level of dependency on the services being assessed.

A more focussed integration of differences in wetland type and an expansion of the method to cater for wetland types not previously included.

 Deletion of 15 indicators and the addition of new indicators.

An expansive revision of the geomorphology module to explicitly differentiate between impacts to geomorphic structure and geomorphic processes.

 Improvements to ease of use of the tool
The addition of the water quality module not previously part of the tool. Refinements to the algorithms used to determine the scores for each ecosystem service.
Revision of the excel spreadsheets with the addition of drop-down boxes for the selection of options and several additional automated calculations to make the spreadsheets more user friendly. Inclusion of more comprehensive guidance in terms of how the results of the ecosystem services assessment will support decision making.
Restructuring of the Level 2 spreadsheet to allow for more rapid data entry and to prevent duplication. An integrated score with supply weighted higher than demand.
Integration of new research and information to refine scoring guidelines. Using the size of the wetland/riparian area as a multiplier for determining functional hectare equivalents for offset calculations.
  The addition of a module to carry out offset calculations for water resource management.
  The addition of recommendations for scoring overall Ecological Importance and Sensitivity (EIS)
 

Confidence scores no longer included for individual indicators.

Implications for wetland assessments in South Africa