Sakhalin Branch, Far Eastern Geological InstituteFar Eastern Department, Russian Academy of Sciences

Technogenic landslide, mudflow and erosion processes on the onshore oil

and gas pipeline route for “Sakhalin II” in the Makarov Region.

June 2, 2007.

N.A. Kazakov, Deputy Director, Federation Council, Far Eastern Geological Institute, Far Eastern Department,

Russian Academy of SciencesMaster of Geo-mineralogical Sciences;

U. V. Geniorovskii, Researcher in the Laboratory of Mudflow and Avalanche Processes, Federation Council,

Far Eastern Geological Institute, Far Eastern Department, Russian Academy of Sciences.

Pul’ka River. Mudflow processes on the route.

The access road and oil and gas pipeline route have been built in the dry wash

The access road and oil and gas pipeline route have been built through an alluvial cone of mud-and-gravel debris to a width of 10 meters.

Pul’ka River. The road embankment is a potential mudflow massif.

The bridge span does not take into account the passage of seasonal floods, or, for that matter, the occurrence of mudflows.

The culvert, set in the dry wash under the roadway, does not take into account the passage of seasonal floods, or, for that matter, the occurrence of mudflows.

Pul’ka River. Pipes are stored in the mudflow alluvial cone in a zone of greatest flood danger.

Mozhaika River. Man-made potential mudflow massifs, created during construction of the access road: the embankment overlays the dry wash. The culvert did not take into account the passage of seasonal floods, or, for that matter, the occurrence of mud flows.

Petrovskii Stream. Man-made potential mudflow massifs, created during construction of the access road and pipeline: the embankments overlay the dry wash. The culvert did not take into account the passage of seasonal floods, or, for that matter, the occurrence of mudflows.

Man-made potential mudslide and landslide massifs, formed while backfilling the oil pipeline. Man-made mudflows threaten the Yuzhno-Sakhalinsk–Okha automobile and rail routes.

Petrovskii Stream. Man-made landslide and potential mudflow massifs, created during construction of the pipeline. Erosion of the slopes.

Stream in the Right Krinka river basin (to the north of Petrovskii Stream). Man-made landslide and potential mudflow massifs, created during construction of the pipeline. Erosion of the slopes. Man-made mudflows threaten the Yuzhno-Sakhalinsk–Okha automobile and rail routes.

The culvert did not take into account the passage of seasonal floods, or, for that matter, the occurrence of mudflows.

Stream in the Right Krinka river basin (to the north of Petrovskii Stream). Man-made landslide and potential mudflow massifs, created during construction of the pipeline. Erosion of the slopes. Man-made mudflows threaten the Yuzhno-Sakhalinsk–Okha automobile and rail routes. The culvert did not take into account the passage of seasonal floods, or, for that matter, the occurrence of mudflows.

Stream in the Right Krinka river basin (to the south of Right Krinka River). Man-made landslide and potential mudflow massifs, created during construction of the pipeline. Erosion of the slopes. Man-made mudflows threaten the Yuzhno-Sakhalinsk–Okha automobile and rail routes. The culvert did not take into account the passage of seasonal floods, or, for that matter, the occurrence of mudflows.

Active erosion of backfill soil above the oil pipeline accompanied by the formation of mudflow. The pipeline is revealed. Anti-erosion construction does not provide protection of the trench from erosion.

Stream in the Right Krinka river basin (to the south of Right Krinka River). Man-made mudflows threaten the Yuzhno-Sakhalinsk–Okha automobile and rail routes. The culvert did not take into account the passage of seasonal floods, or, for that matter, the occurrence of mudflows.

The man-made mudflow (muddy stream) flowed downward along the stream more than 50 meters (the density of the mud deposits is up to 2 meters, width up to 5 meters).

The man-made landslide-flow, which was formed from backfill soil above the oil pipeline, flowed from the route into the streambed and transformed into a mudflow.

Waste construction soil at the surface of a landslide massif to the south of Right Krinka River. Man-made landslide massifs. The wooden fence is not capable of averting the development of landslide processes.

Right Krinka River. Man-made potential mudflow massifs, created during construction of the pipelines. Man-made landslide massifs. Man-made mudflows threaten the Yuzhno-Sakhalinsk–Okha automobile and rail routes. The culvert did not take into account the passage of seasonal floods, or, for that matter, the occurrence of mudflows.

CONCLUSIONS

1. Anti-erosion measures do not ensure the protection of waterways from soil runoff from the pipeline route, which has been contaminated by the work of heavy equipment during pipe laying.

2. As a result of the active development of erosion and landslide processes on mountain slope sections of river and stream valleys, active wash-out of backfill soil above the sections of the oil pipelines that have already been buried, and runoff of soil contaminated by the work of heavy equipment into waterways, are taking place.

2. Culverts under the oil pipeline route and access roads did not take into account the passage of seasonal floods which appear even with precipitation of average intensity, or, for that matter, the occurrence of mudflows. Accordingly, the culverts will ensure neither the safety of the pipelines nor of the access roads.

3. In the mountain slope sections of the river valleys and streams of all waterways in the Krinka, Mozhaika, and Pul’ka river basins, and the Petrovskii Stream, man-made potential flood massifs were created during construction of the pipelines, the activation of which will lead to the destruction of the route itself.

4. On all waterways in the Krinka, Mozhaika, and Pul’ka river basins, and Petrovskii Stream, man-made potential flood massifs were created during construction of the pipelines. During the periods of mudflow formation, this will lead to a sharp increase in the volume and range of mudflow discharge, and also an increase in the frequency of river-bed silt formation

5. On all waterways of the Krinka, Mozhaika, and Pul’ka river basins, and Petrovskii Stream, active erosion, landslide and mudflow processes have begun, caused by construction work on the oil and gas pipelines. In a number of sections these processes have led to the uncovering of the already buried pipeline.

6. In the river basin of Right Krinka (the river’s right tributary), a man-made landslide flow, which was formed from the backfill soil above the oil pipeline, left the pipeline route, flowed into the stream bed, and transformed it into a mudflow. The man-made mudflow (muddy stream), with a volume of more than 1000 meters3, flowed downward along the stream away from the route more than 50 meters. The density of the mud deposits in the stream bed is up to 2 meters, with a width up to 5 meters.

7. The technical designs adopted by the Company regarding the intersections of mud- and landslide-prone sections have led to the creation of conditions for the formation of man-made mudflows on the Mozhaika and Krinka rivers, and Petrovskii Stream. Based on their parameters, these mudflows present a threat to the Yuzhno-Sakhalinsk–Okha automobile and rail routes between the city of Makarov and the village of Tumanovo.