The project received environmental approvals on 11-May-20 on the basis of an Environmental Impact Assessment completed on 19-Apr-20 and additional information submitted on 06-May-20. As a result of design changes an EIA Addendum is currently under preparation. This EIA Addendum will evaluate the impact of dredging and reclamation of an additional 4.5 million m³ of sand, which necessitates the expansion of the primary borrow areas by 4.5 km². It will also evaluate the impact of two different Alternative Borrow Areas than were identified in the original EIA.

In addition, a Supplementary Environmental and Social Impact Assessment has been prepared to support project financing.

At the time of preparing the Supplementary ESIA, the expected extra sand volume required for the design changes to the project was 4 million cubic meters. Based on newly available information the correct additional sand volume figure is 4.5 million cubic meters. The EIA Addendum contains the adjusted sand volume figure. The change in required sand volume has not affected the assessment of impacts related to the design change.

As part of E(S)IA development, turbidity plume modelling was undertaken by Deltares, Netherlands, to understand the scale and magnitude of impact from dredging and land reclamation on the water turbidity levels. The focus of the turbidity modelling was also to determine an Area of Influence (AoI) by understanding spatial extent of the impact. 

The turbidity plume dispersion model was set up using a hydrodynamic model developed by Deltares. The model simulates the local hydrodynamic climate (i.e. currents driven by tide and wind), which determines the dispersion of turbidity. 

Based on the work method for the Project, a set of scenarios was determined. Scenarios differed in the size of TSHD used (“Large” and “Jumbo”), the monsoon season simulated (Northeast and Southwest) and the location of dredging within the borrow areas (yellow markers in below image).

Then, each scenario was modelled for a 15-day period (including a spring and neap tide cycle as per common practice), thereby predicting the concentration and spatial extent of each generated turbidity plume. Plume generation is alternating between a dredging location and the reclamation area (green-marked location), in line with the process of dredging and pumping ashore the sandy material. As a worst-case scenario, the lagoon was modelled to be nearly filled already, with the location of pumping ashore closest to the exit of the lagoon.

Below GIF shows the surface plume simulations with a “Large” size TSHD, during the Northeast monsoon period, dredging from the location directly north of Gulhifalhu within the Primary Borrow Area, as an example.

Thereafter, a composite ‘envelope’ image is generated for each scenario, by combining all the plumes simulated during the 15-day period. These images are therefore not a snapshot/aerial view of a single point in time, but a combination of all simulated turbidity over 15 days. The red line shows the area within which, during a 15-day period, the chance of TSS levels exceeding 10 mg/l, is more than 2%. This can therefore also be interpreted as the area within which TSS levels are expected to exceed 10 mg/l for more than 2% of the time. Consequently, outside this area exceedance is predicted less than 2 % of the time.  Below image is the composite image of the same scenario as above GIF: “Large” size TSHD, during the Northeast monsoon period, dredging from the location directly north of Gulhifalhu within the Primary Borrow Area.