concept EIA-rapport - Staatsolie

SRK Consulting: Project No: 439414 Staatsolie Pipeline EIA – Draft EIA Report Page 20
3.4.1 Route alternatives
The alignment of the pipeline has been refined and adjusted by Staatsolie at several junctures
in the design process based on environmental conditions and extensive talks with landowners.
Initially, two general alternative alignments were investigated for the pipelines:
• A terrestrial alignment, which relied mainly on trenching; and
• An alignment along and underneath the Suriname River (described in Section 3.3.2),
which relies mainly on HDD and only makes use of trenching where required to establish
connections.
During the course of the technical prefeasibility investigation, it became apparent that the
terrestrial alignment is not viable, since negotiations with landowners to secure servitudes and
rights of way were not successful and prospects of reaching agreement in the future are
considered extremely unlikely. The terrestrial alignment thus no longer represents a
feasible alternative, and has not been assessed in the impact assessment.
Apart from impacting fewer properties, the river alignment has a number of other advantages
over the land alignment:
• The alignment is straighter, which makes it easier to clean the pipeline by pigging and
requires fewer pigging stations (likely only one);
• HDD has fewer impacts on land and water bodies than trenching, as it only requires
construction activities at the entry / exit points;
• The pipeline is less at risk of third-party interference as it lies deeper;
• Due to its greater depth, the pipeline only requires occasional monitoring of pipeline
stresses (with a focus on the tie-ins) and soil cover (with a focus on the shallower
sections);
• Due to its depth, the pipeline does not sterilize land located above the pipeline; and
• Maintenance of the pipeline corridor is essentially restricted to the entry / exit points, and
does not require marking and maintenance of an exclusion zone along the entire corridor.
Generally, the detailed alignment of the pipeline and its entry / exit points has been chosen
and amended to have minimal impact on adjacent land use and structures (also see Section
3.3.3.2 in this regard).
3.4.2 Construction method alternatives
A number of construction methods were considered for the pipeline. Some of these are
specific to the pipeline alignment, i.e. the previously considered terrestrial alignment relied
more heavily on trenching, while the alignment underneath the Suriname River has to
predominantly make use of HDD and cannot be achieved with trenching alone.
Construction methods that are and have been considered include:
• Open trenching on land: This method involves the digging of a trench to the desired
depth at which the pipeline will lie. The pipe is laid into the trench, which is then backfilled
with the excavated soil. Problems associated with this construction method include the
presence of construction crews and disturbance of land along the entire pipeline route,
higher maintenance effort of the pipeline corridor as well as the pipeline’s shallow depth
and hence vulnerability to interference from third parties.
Trenching was considered as the main construction method for the terrestrial alignment.
Since that alignment has been screened out, trenching is restricted to short sections
REUT/DALC 439414_StaatsoliePipelineEIA_Draft EIA Report_Final
June 2012