A preliminary study has shown that the use of a high-strength composite fiber cloth material may greatly reduce fabrication and deployment costs of a subsea offshore pipeline. Above-water pipelines are often not feasible due to safety, cost, and environmental problems, and present, fixed-wall, submerged pipelines are often very expensive.
This technology can safely transport large quantities of fresh water, oil, and natural gas underwater for long distances.
The solution is to have a submerged, compliant-walled tube that when filled, is lighter than the surrounding medium. Some examples include compliant tubes for transporting fresh water under the ocean, for transporting crude oil underneath salt or fresh water, and for transporting high-pressure natural gas from offshore to onshore.
In each case, the fluid transported is lighter than its surrounding fluid, and thus the flexible tube will tend to float. The tube should be ballasted to the ocean floor so as to limit the motion of the tube in the horizontal and vertical directions. The tube should be placed below 100-m depth to minimize biofouling and turbulence from surface storms. The tube may also have periodic pumps to maintain flow without over-pressurizing, or it can have a single pump at the beginning. The tube may have periodic valves that allow sections of the tube to be repaired or maintained. Some examples of tube materials that may be particularly suited for these applications are non-porous composite tubes made of high-performance fibers such as Kevlar, Spectra, PBO, Aramid, carbon fibers, or high-strength glass.
Above-ground pipes for transporting water, oil, and natural gas have typically been fabricated from fiber-reinforced plastic or from more costly high-strength steel. Also, previous suggested subsea pipeline designs have only included heavy fixed-wall pipes that can be very expensive initially, and can be difficult and expensive to deploy for long distances. A much less expensive Kevlar pipeline can be coiled up on a ship’s deck and deployed in the water as the ship moves. Support ships can be used to drop sand into conduits below the uninflated tube, so that the tube remains in place when more buoyant fresh water later fills the tubes.
This work was done by Jack A. Jones and Yi Chao of Caltech for NASA’s Jet Propulsion Laboratory. NPO-47455
This Brief includes a Technical Support Package (TSP).
Improved, Low-Stress Economical Submerged Pipeline
(reference NPO-47455) is currently available for download from the TSP library.
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Overview
The document presents a preliminary technical feasibility study on submerged aqueducts, specifically focusing on the potential for transporting water from the Columbia River in Oregon to California. Authored by engineers and scientists from NASA's Jet Propulsion Laboratory, the study explores innovative methods for creating low-stress, economical submerged pipelines that could address water scarcity issues in California.
Key highlights include the consideration of various water sources, such as unused Columbia River water, which Oregon has contemplated selling to California to alleviate budget deficits. The study also discusses the feasibility of delivering water from Northern California to Southern California, as well as from Northern Florida to drought-affected Central Florida. The proposed aqueducts would utilize advanced materials, including Kevlar, to construct pipelines that can withstand the challenges of underwater environments.
The document outlines the technical aspects of the project, including the design of two 1,200-km pipelines capable of delivering 3 million acre-feet of water per year to San Francisco Bay. The estimated cost for each pipeline is under $1.5 billion, making it a potentially viable solution for water distribution. NASA has already conducted successful tests on a Kevlar tube, demonstrating its practicality for such applications.
Further studies are recommended to refine the project, focusing on materials optimization, tube fabrication, installation costs, and environmental considerations. The document emphasizes the importance of conducting detailed stress analyses, oceanographic studies, and legal assessments to ensure the project's feasibility and sustainability.
Overall, the study presents a promising approach to addressing water shortages through innovative engineering solutions. It highlights the potential for collaboration between governmental and scientific entities to develop infrastructure that can effectively transport water across challenging terrains. The document serves as a call to action for further research and investment in submerged aqueduct technologies, aiming to provide a reliable water supply for regions facing drought and water scarcity.
