Exxaro Grootegeluk Wetland Relocation.

The video summarising this project can be viewed here:

https://www.youtube.com/watch?v=hxadmmh-gWQ&t=58s

Summary

Exxaro’s Grootegeluk opencast coal mine in Limpopo Province, South Africa, proposed an expansion in mining operations that would destroy non-perennial pans. To mitigate the damage, Exxaro engaged with GroundTruth on a novel pilot project that attempted to relocate non-perennial wetland pans outside the mining operational area. Six non-perennial pans were created, using material (i.e., natural wetland soils and plants) from two large ‘donor pans’.

In this novel pilot, three different scenarios, each comprising two pans, were created:

• Scenario 1. This scenario involved recreation of wetland habitat under ‘less desirable’ conditions – conditions with little vegetation cover resembling a post-mining. In this scenario, artificial liners were incorporated into the design to ensure water was retained.
• Scenario 2. This scenario involved recreation of wetland habitat underlain by shallow calcrete. This system was created through excavating the material to the bedrock layer.
• Scenario 3. This scenario involved recreation of wetland habitat using only the materials and substrate obtained from the donor pans.

GroundTruth led the placement, design, and construction of the wetlands under each scenario, resulting in six new, relocated non-perennial wetland systems. The next step was designing a monitoring and evaluation protocol, in accordance with the principles outlined in WET-RehabEvaluate, to follow for assessing the efficacy and longevity of the wetlands to determine which of the scenarios functioned best.

As part of the monitoring protocols, GroundTruth conducts in-field surveys and collects samples to assess the invertebrate community, surface water quality (i.e., pH, temperature, electrical conductivity, clarity, and turbidity), and the general ecological conditions onsite.

Two rainfall seasons since the new pans were created, monitoring indicates that the wetlands are functioning as they should. They are holding water, wetland vegetation is now dominant, aquatic invertebrates are resident, and other wetland-associated fauna are using the pans.

Monitoring at the pans is ongoing, which will facilitate adaptive management of the systems.