2.9. Pilot project: Cleanup of tiksi bay seafloor from sunken logs and wrecks. Phase 2

 

The Project Goal was to protect the biosphere in the marine and coastal zone of Tiksi Bay and the Gulf of Bulunkan from man-induced pollution. This Pilot Project was aimed at completing the cleanup of the seafloor from sunken timber and wrecks of five ships in water area of Tiksi Bay as a follow up of the works carried out in 2008-2009.

The Project was implemented by Open Joint Stock Company “Tiksi Sea Port”.

The Project Duration                        01 December 2009 – 30 November 2010

The Project Activities

Stage 1
The seafloor was dredged to lift the sunken logs, load them onto a seaborne barge, and transport the logs, wire and cable wire to the onshore offloading point, where the dredged items were offloaded, with the logs graded, and stacked.

Stage 2
Works were carried out to lift and transport three sunken ships without violating the integrity of their hulls. The ships were floated by cleaning their decks from accumulated soil and garbage (i.e. wire, cables, etc.). Diving operations were also carried out to cut out technological openings for the holds to be dried. Water pumps were installed and water pumped out. As the ships were floated they were towed to the cutting and demolishing site.

Stage 3
Two ships, submerged near the shore, were pulled on shore with a pull winch, with their hulls cut in a step by step way. A ship was pulled out of water onto the shore, with the garbage removed. Holds were then dried up. Part of the ship was then cut out onshore to be then separated into smaller portions and transported onshore for disposal.

Stage 4
Carrying out of the “Baseline Study of Physico-Chemical Contamination of the Seafloor Sediments and Seawater in Tiksi Bay”

The Project Outcomes

In Tiksi Bay, remediation activities resulted in environmental improvement of over 100 km2 of water area and about 1 billion m3 of water mass. This will lead to health improvement of over 15,000 inhabitants of northern settlements including 5,000 representatives of small-in-numbers indigenous peoples of the North, whose main diet includes northern fish species, since fish products will be of better quality and there will be more fish for local people.

From June 15 to July 16, 2010, the seafloor of the Gulf of Bulunkan was dredged with a grappler installed on the floating crane to lift the sunken logs, load them onto a seaborne barge, and transport the logs to the onshore offloading point. The barges were towed by the VOLNA RBT harbor pusher tug. On the shore, the logs in an amount of 990 m3 were unloaded, graded and stacked. The dredging yielded positive indicators of water quality after the cleanup works.

Fig.24
Figure 24. Sunk Timber Raised from Bulunkan Sea Floor

In August 01-31, 2010, works were carried out to lift and transport three sunken ships without violating the integrity of their hulls.

Fig.25
Figure 25. Transportation of Ship Lifted on Surface

The ships were floated by cleaning their decks from accumulated soil and garbage. Diving operations were also carried out to cut out technological openings for the holds to be dried. As the ships were floated they were towed to the cutting and demolishing site.

Fig.26
Figure 26. Cutting and Utilization of Ship Lifted from Sea Floor

In September 02-30, 2010, two ships, submerged near the shore, were pulled on shore with a pull winch, with their hulls cut in a step by step way. A ship was pulled out of water onto the shore, with the garbage removed. Holds were then dried up. Part of the ship was then cut out onshore to be then separated into smaller portions for disposal.

At stage 4, the Project entered into a contract with FGU "The State Nature Reserve Ust’ - Lensky" for the works titled “Baseline Study of Physico-Chemical Contamination of the Seafloor Sediments and Seawater in Tiksi Bay”. From the “Baseline Study of Physico-Chemical Contamination of the Seafloor Sediments and Seawater in Tiksi Bay” Report one may conclude that the cleanup operations (removal of sunken logs and ships) had positive effects on the environmental status of the water area.

The following conclusions were drawn as a result of the Pilot Project implementation:

  1. Intensive decaying of the sunken logs leads to dangerous and toxic chemical contamination of water. Sunken larch trees are a source of long-term accumulation of nutrients and organic matter in water. A five-year contact with water does not ensure total of leaching of biogenic matter from wood.
Fig.27
Figure 27. Layout of Hydrochemical Stations in Tiksi Bay
  1. Chemical contamination of water has a negative impact on wintering, feeding and spawning of the most valuable commercial species of the Arctic fish. This requires not only the continuation of cleanup operations, but their intensification
  1. Providing local (indigenous) people with firewood from the logs so lifted will help conserve forests since there will be no need for felling forests
  1. Sunken wrecks pose environmental threats and could be dangerous for the local population. The works with the wrecks were carried out in accordance with the Contract and basic technologies of ship lifting and transportation without violating the integrity of the ships. The ships were dragged onshore and cut out in a staged way by separating parts of their hulls.
  1. From the environmental point of view, the wreck floating and lifting techniques were the right choice since they were not associated with sediment detachment and subsequent generation of vast areas of contaminated suspended matter. Suspended matter could increase concentrations of both suspended matter and pollutants accumulated in the sediments, in particular, petroleum products. This was not the case in the implementation of this contract, since the wrecks moved at a speed of smooth bottom deformation causing no breakup in the surrounding sediment mass.
  1. Future cleanup operations will definitely lead to significant improvements in the environmental status of the Tiksi Bay and the Gulf of Bulunkan basin

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