This page summarizes what we now know about mitigation of sand harvesting impacts to the adjacent coral reef. On 10th April observation onboard the dredger Willem van Oranje was done, to see the operations in person, and identify what practices, if any, could be effective to reduce the threat to coral reefs. See the tab below for information on these three key questions:
1) What are the primary threats from sand harvesting?
2) How do the sediment plumes impact reefs?
3) How can the threats and impacts be reduced?
Given the mitigation actions applied since 4 April, the risk of damage to Kwale coral reefs is reasonably low.
SCUBA surveys to date have shown LOW impact to the reefs in terms of coral mortality, and observations summarized above indicate the risk to coral reefs can be reduced even further.
The dredging vessel has been implementing the shuttle overflow and green valve since it re-started operations on 4 April. Some modifications to the procedure (e.g. the 1.5 km mitigation line for discharge in part 3 above) and additional measures such as identified under mitigation action 3 may reduce even further the risks from sand harvesting.
Many of the fears expressed by stakeholders, in particular the claim “sand harvesting is killing Diani coral reefs” are not true. Stakeholders are afraid of this, as we were when there was no clear information. But having observed the reef we know that it is not true. The risk of future damage, which is still a concern, is now fully addressed by the mitigation actions above, and the new monitoring plan which is ready to implement.
Active monitoring will ensure that critical thresholds are not exceeded for:
- a) the amount of sediment in the water reaching the reef (monitored daily);
- b) the amount of sediment settling on the reef (monitored weekly); and
- c) the health of hard and soft corals (monitored weekly).
IN SUMMARY- The way the sand harvesting was being done before 27 March was demonstrably showing build-up of impact, and it was stopped BEFORE impacts became serious. The current mitigation and monitoring actions SHOULD have been developed from the original EIA and in the EMMP. But the main mitigation actions are already being implemented, and the monitoring actions are implementation-ready. Together we are confident they WILL be able to prevent significant damage as wanted by all stakeholders.