Restoring a Critical Raw Water Supply Without Trenching Through Wetlands
Overview
A major U.S. refinery was losing water from a critical raw water supply line measuring 30 inches in diameter and approximately 2,000 feet long. The concrete pipeline ran beneath federally managed land and environmentally sensitive wetlands, making conventional excavation difficult to permit, environmentally disruptive, and financially unpredictable. Motivo cleaned, inspected, and rehabilitated the pipeline from the inside using flexible fiber reinforced pipe, or FFRP. The refinery restored its primary water supply without continuous trenching through the protected areas.
The Challenge
Raw water is essential to refinery operations because it supports cooling systems, heat exchangers, boilers, steam generation, and other processes throughout the facility. The refinery knew the pipeline was leaking because the volume of water entering the line did not match the volume reaching the plant. Water was also rising to the surface and forming ponds above portions of the buried pipe.
The location made conventional excavation and replacement especially challenging. The line descended a steep slope beneath federally managed land and then continued for approximately 1,700 feet through wetlands. Much of the pipeline also ran beneath property the refinery did not own. Excavation would have required environmental permitting, coordination with property owners, dewatering, trench shoring, and restoration of the disturbed land and wetlands. Wet and unstable soils would also have increased the risk of the excavation sloughing or collapsing, creating significant uncertainty around the project’s cost and schedule.
An aboveground replacement line was considered, but it would still have crossed wetlands and property controlled by others. The refinery therefore needed a solution that could use the existing buried pipeline rather than requiring a new route through the protected areas.
The leaking 30 inch line was the refinery’s primary water supply. While it was unavailable, the facility continued operating from a secondary 18 inch line. This allowed the plant to remain operational, but it also left the refinery dependent on a single remaining water source. If that line failed, the facility could lose the water required to support normal operations.
Why a Point Repair Was Not Enough
The concrete host pipe had deteriorated beyond one isolated defect. A localized repair might have stopped one visible leak, but repressurizing the pipeline could have caused another weakened section to fail. When similar deterioration exists throughout a pipeline, repairing one location can simply move the failure to the next vulnerable area. The refinery needed a solution that addressed the full pipeline rather than relying on a series of temporary repairs.
The Solution
Motivo first inspected the pipeline to identify major voids, missing pipe sections, or other defects that could interfere with the lining process. If the inspection had revealed a large section of missing pipe, Motivo could have installed a fiberglass point repair before installing the full length liner. In this case, the inspection showed that the host pipe did not require additional structural repairs before lining.
The pipeline was then cleaned by pigging. To establish the pulling system, Motivo used a pneumatic device to propel a lightweight rope through the pipe. That rope was used to pull a heavier winch cable into position, and the winch cable provided the force needed to install the liner through the approximately 2,000 foot pipeline.
Motivo installed a factory manufactured FFRP liner through the existing host pipe. Unlike cured in place pipe, FFRP arrives at the project site fully manufactured and does not require resin curing inside the pipeline. The liner was folded to reduce resistance during installation, pulled into position, inflated, and connected to the refinery’s piping system using engineered flange fittings.
The FFRP system included an inner layer selected for the material being conveyed, a polyester or Kevlar reinforcement layer designed for the required pressure, and a durable polyethylene exterior layer. Once the liner was in position, Motivo inflated it, secured it to the termination fittings, and connected the rehabilitated pipeline back into the refinery’s system.
Why FFRP Was the Right Approach
FFRP was well suited for the project because it could be installed over a long distance while accommodating the pipe’s existing geometry. Rigid sliplining was another possible trenchless method, but it would have required a long installation ramp and could not easily accommodate the pipeline’s steep descent and 45 degree bend. Because FFRP could be folded during installation, it reduced pulling resistance and could follow the existing pipe more effectively.
This approach allowed the refinery to rehabilitate the pipeline in place rather than creating a new buried or aboveground route through federally managed land and wetlands. It also avoided many of the permitting, property access, and environmental complications associated with conventional replacement.
The Result
Motivo restored the refinery’s primary raw water supply without continuous trenching through the protected areas. The active cleaning and rehabilitation work was completed in approximately one week, compared with an estimated month or more for conventional excavation and replacement. The facility remained operational using its secondary water supply while the primary line was rehabilitated.
The project minimized environmental disturbance and avoided the uncertainty associated with wet trenches, unstable soils, dewatering systems, extensive shoring, and restoration of the disturbed land. It also addressed the entire pipeline by creating a continuous pressure barrier through the existing host pipe rather than repairing one leak at a time.
Motivo completed the project for approximately $2 million. It is estimated that conventional excavation and replacement would have cost approximately $1 million more under favorable conditions. If wetland excavation, dewatering, shoring, soil instability, permitting, or other complications occurred, the difference could have reached approximately $10 million.
A Practical Alternative to Dig and Replace
Buried pressure pipelines frequently run beneath roads, railroads, operating units, waterways, wetlands, and property controlled by others. In these environments, the cost of replacement extends far beyond the new pipe. Excavation can introduce permitting requirements, dewatering, shoring, property access challenges, environmental restoration, soil remediation, and operational risks.
By cleaning, inspecting, and rehabilitating the pipeline from the inside, Motivo gave the refinery a faster and more predictable path to restoring a critical water supply. FFRP may be a strong option for other long pressure pipelines with few branches or connections, particularly when excavation would be costly, disruptive, or environmentally difficult.