A pipeline construction project looks much like a moving assembly line. A large project typically is broken into manageable lengths called “spreads,” and utilizes highly specialized and qualified workgroups. Each spread is composed of various crews, each with its own responsibilities. As one crew completes its work, the next crew moves into position to complete its piece of the construction process.
These tasks include:
- Pre-construction survey
Before construction begins, crews survey environmental features along proposed pipeline segments. Utility lines and agricultural drainages are located and marked to prevent accidental damage during pipeline construction. Next, the pipeline’s centerline and the exterior right of way boundaries are staked.
- Clearing and grading
The pipeline right of way is cleared of vegetation. Temporary erosion control measures are installed prior to any earth-moving activities.
Topsoil is removed from the work area and stockpiled separately in agricultural areas. Crews use backhoes or trenching machines to excavate a pipeline trench. The soil that is excavated during ditching operations is temporarily stockpiled on the non-working side of the trench.
- Pipe stringing
Individual joints of pipe are strung along the right of way adjacent to the excavated ditch and arranged so they are accessible to construction personnel. A mechanical pipe-bending machine bends individual joints of pipe to the desired angle at locations where there are significant changes in the natural ground contours or where the pipeline route changes direction.
- Welding and coating pipe
After the stringing and bending are complete, the pipe sections are aligned, welded together, and placed on temporary supports along the edge of the trench. All welds are then visually and radio graphically inspected. Line pipe, normally mill-coated or yard-coated prior to stringing, requires a coating at the welded joints. Prior to the final inspection, the entire pipeline coating is electronically inspected to locate and repair any coating faults or voids.
- Lowering pipe in and backfilling
The pipe assembly is lowered into the trench by side-boom tractors. The trench is backfilled using a backfilling or bladed equipment; no foreign materials are permitted in the trench.
After backfilling, the pipeline is hydrostatically tested following federal regulations. Test water is obtained and disposed of in accordance with applicable federal, state and local regulations.
Our policy is to clean up and restore the work area as soon as possible. After the pipeline is backfilled and tested, disturbed areas are restored as close as possible to their original contours. Restoration measures are maintained until the area is restored, as closely as possible, to its original condition.
Special Land Considerations
The Hilabee project is being designed to minimize the impact to residential areas, as well as agricultural lands. Land disturbed during the construction period will be returned to as close to original condition as possible. Agricultural lands will be properly restored using approved, modern mitigation techniques designed to ensure full productive reuse of the agricultural lands.
Crossing Agricultural Land
Farmers and other landowners are encouraged to be active participants throughout all phases of the Hilabee project, beginning with the initial land surveys and continuing until crop yields are restored.
All mitigation techniques used throughout the project will be completed by, and at the expense of, Williams. It will be the day-to-day job of the project’s assigned inspectors to monitor and supervise construction and restoration activity for compliance with approved agricultural right-of-way standards relative to the region, as well as all relevant FERC standards.
One of the first opportunities for collaboration occurs during the initial surveying and line staking activities. Landowners are invited to accompany the surveyor during the initial review of the land. As the people most familiar with the property, farmland owners and operators are in the best position to share useful information with the construction engineers, surveyors and land representatives during project planning. Examples of the information that will assist Williams in protecting your land include: drainage patterns, intensive tile drain systems, grassed waterways or diversion terraces, location of water lines to buildings, developed springs or livestock watering facilities, depth to high water table, soil type, topsoil thickness, the rock or boulder content of the deeper subsoil, and depth to the bedrock. Some of this information can be found in the farm conservation plan, in the County Soil Survey or from the local technician at the County Soil and Water Conservation District. During the survey phase and again, early in the construction phase, reference stakes are commonly used to mark the land. Wooden stakes are required because metal survey spikes can be dangerous to livestock and damage farm equipment.
A right-of-way agreement allows for the use of a portion of your land for locating our pipeline. Landowners are offered financial compensation in exchange for granting a permanent easement to Williams. A contract for a right-of-way is a standard easement agreement, but can be tailored if necessary to meet a landowner’s unique concerns.
It is important for all landowners, but especially owners and operators of agricultural lands, to know that FERC will require compliance with a comprehensive mitigation plan for all land uses, particularly agricultural lands, and will enforce compliance with that plan as part of its ongoing inspection of the construction and restoration activities.
The first essential part of right-of-way “clearing” in farmland areas involves removing the topsoil from the right-of-way. If the topsoil is not fully removed prior to construction, it may be permanently damaged by the pipeline work, due to rutting, compaction, and the inversion and mixing of the soil layers. To avoid this, the topsoil is stripped and stored safely. It must be segregated and stockpiled away from the pipeline trench, the excavated spoil, the pipe assembly area and the traffic zone. The full thickness of the topsoil zone is typically twelve inches.
Protecting Drainage & Irrigation
Prior to construction, company representatives will work with you to locate existing drain tiles and irrigation systems. The company will also work with you and local soil conservation authorities to determine the location of future drain tiles that may be installed. The information we learn will be used to develop specific procedures for constructing in drain tile areas. These procedures will also address how the company plans to maintain irrigation systems during construction and, in the event that drain tiles or irrigation systems are damaged, how the company intends to facilitate repairs. Williams will retain qualified drain tile specialists to conduct any necessary repairs in a prompt and careful manner.
In areas where drain tiles exist or are planned, the company will ensure that the depth of cover over the pipeline is sufficient to avoid interference with drain tile systems. Williams will check all drain tile systems within the area of disturbance to check for potential damage. If any tiles are damaged, they will be repaired to their original or better condition by a qualified drain tile specialist.
Decompaction & Rock Removal
Because the topsoil is removed and stockpiled for protection, the exposed subsoil serves as the surface of the construction roadway for the duration of the project. This traffic can heavily compact the subsoil. Williams’ environmental inspector will test the subsoil to measure compaction. Severely compacted areas will be plowed with a paraplow. In areas where the topsoil has been segregated, the subsoil will be plowed before replacing the segregated topsoil.
Crews will remove excess rock from at least the top 12 inches of soil in all agricultural areas. Once construction is complete, the size, density and distribution of rock within the pipeline work area will be restored to the same consistency as areas not affected by construction.
Coordinating with Appropriate Agencies
Williams will coordinate with appropriate local, state and federal agencies any construction and restoration measures specifically involving affected farmlands. This will include working with local soil conservation authorities or land management agencies to address erosion control and revegetation. The company will also work with appropriate agencies to create specific procedures to prevent the introduction or spread of noxious weeds or soil pests resulting from pipeline construction.
As soon as backfill operations are complete, crews will commence cleanup and restoration activities, including completion of final grading and topsoil replacement. The construction right of way will be graded to restore pre-construction contours. The environmental inspector will oversee that the restoration of contours and topsoil are returned to their original condition. Williams will conduct follow-up inspections of all disturbed areas after the first and second growing seasons to ensure the success of revegetations. Revegetation in agricultural areas shall be considered successful if crop yields are similar to adjacent undisturbed portions of the same field.