2.1 Overview of the Proposed Project - Keystone XL pipeline - US ...

Draft Supplemental Environmental Impact StatementKeystone XL ProjectPipeline Construction SequenceFigure 2.1.7-2 shows a typical pipeline construction sequence. The design and construction ofthe pipeline would incorporate each of these steps. Additionally, the proposed Project wouldinclude additional construction for access roads, construction work camps, and temporaryworkspace facilities. All aspects of proposed Project construction are addressed in the remainingsections of this section.Standard pipeline construction is composed of specific activities, including survey and staking ofthe ROW, clearing and grading, pipe stringing, bending, trenching, welding, lowering in,backfilling, hydrostatic testing, and cleanup. In addition to standard pipeline constructionmethods, special construction techniques would be used where warranted by site-specificconditions. These special techniques would be used when constructing across rugged terrain,sensitive areas, waterbodies, wetlands, paved roads, highways, and railroads (see Section 2.1.8,Special Pipeline Construction Procedures).Construction would be planned to continue into the early winter months for as long as possiblewithout the use of special winter construction techniques. However, as stated in the CMRP(Appendix G), if the proposed Project is authorized and winter construction is necessary to meetconstruction deadlines, Keystone would consult with the relevant federal, state, and localregulatory agencies to determine what changes may be necessary in permits issued, whatadditional permits may be required, and to identify the procedures that would have to beincorporated into construction to avoid or minimize environmental impacts. Winter constructionplans would be finalized based on those consultations and permit requirements. Normalconstruction activities would be conducted during daylight hours, with the following exceptions:• Completion of critical tie-ins on the ROW may occur after daylight hours. Completionrequires tie-in welds, non-destructive testing, and sufficient backfill to stabilize the ditch.• HDD operations may be conducted after daylight hours, if determined by the contractor to benecessary to complete a certain location. In some cases, that work may be requiredcontinuously until the work is completed; this may last 24 continuous hours or longer. Suchoperations may include drilling and pull-back operation, depending upon the site and weatherconditions, permit requirements, schedule, crew availability, and other factors. Prior toconstruction, the presence of residences in proximity to the proposed HDD activities wouldbe determined. HDD activities would be conducted consistent with any applicable local noiseordinances.• Hydrostatic testing operations may be conducted after daylight hours if determined by thecontractor to be necessary to complete a certain location. In some cases, that work may berequired continuously until the work is completed; this activity may take place for 24continuous hours or longer.• While not anticipated in typical operations, certain work may be required after the end ofdaylight hours due to weather conditions, for safety, or for other proposed Projectrequirements.Project Description 2.1-40 March 2013