Claim 5000465 - Remediation of Damage to Marine Resources (US$6,172,274)

     The Kingdom of Saudi Arabia was awarded US$6,172,274 for damages to the marine environment caused by sunken oil, which impacted biotic communities in sub-tidal habitats.

     As at the time the Programme mandate was declared fulfilled in the case of Saudi Arabia, this project was substantially complete.

     Under the plan, an area in Balbol was designated for remediation as elevated contamination of ‘sunken oil” up to 61,000 milligrammes was recorded and was having adverse impacts on ecological communities that live in the sediments. The original remediation approach was to involve targeted dredging of contaminated sediments, landfilling of the dredged sediments and post remediation activities to evaluate ecological risks and remediation effectiveness. However, following a resurvey of the site, it was found that the area with the highest contamination was in fact located on an intertidal sand flat/bar complex that sits atop the southern end of an intertidal rock platform at the mouth of Dawhat Balbol and was exposed during low tides. The site was therefore a candidate for land based, rather than marine based activities and could be treated in similar manner to the other coastal award contracts.

     Remediation involved the removal of Asphalt Pavement (AP) from the unconsolidated sediments atop the rock platform and the remediation of the sediments below the AP. Removing the AP eliminated a chronic source of oiling from this area and removed the physical barrier formed by the hard surface cap. After removal by the excavator, a sweep of the area was done manually to remove pieces too small to target mechanically.  Nearly 35,000 m² of the tidal flat was tilled to mix and release residual oil in the sediments, increase oxygenation in the sediment, and break up any thin consolidated oil layers.

     Once excavated, the spoil material was transported to a temporary staging area in a supratidal location adjacent to the work site. The temporary staging area was lined with landfill liner to prevent any possible leaching of the contaminants to the underlying sediment. Chemical analysis indicated that, though the waste contained oil, it was not considered hazardous waste and alternative use of the material was warranted provided it remained out of the intertidal area and was used in a way that would not allow leaching.  The waste was eventually transported approximately 20 km south to be used as road base in the construction of the access roads to Manifa. The material was mixed and laid down and was finally capped with road surface materials.

     Following the remediation, the sand flat was rapidly re-colonized by burrowing and grazing fauna. Species that were not able to colonize the AP returned to the site in a matter of months.