Climate Change Resiliency of Natural Gas Pipelines: Overview of Land Subsidence and Associated Issues in Central California

Natural gas pipeline systems may be impacted by several aspects of climate change, such as changes in the maximum and minimum temperature; higher thermal stress; heavy precipitation and flooding due to increased runoff; more frequent hurricanes; more frequent landsliding; and more frequent land subsidence. Land subsidence in California is attributed to two main sources, groundwater pumping and oil extraction. Of the two sources, groundwater pumping has been identified as the main cause and the annual rate of land subsidence can reach more than 1 foot per year. In Central California, due to the current drought, more groundwater is being extracted; therefore, land subsidence has become a major issue in Kern County and San Joaquin Valley. This paper discusses the long-term and short-term indirect impacts of climate change on land subsidence, and the direct impacts of land subsidence on existing natural gas pipelines. This study utilizes available data and evaluates the potential impact on natural gas pipelines in Central California using a finite element model and a simplified soil-pile interaction modeling technique. We explore the effects of not only vertical subsidence on a selected gas pipeline but also the effects of horizontal ground movement. This paper illustrates how drought, an element of climate change, which causes greater use of groundwater pumping, may be incorporated in the planning, design, construction, operation, and maintenance of pipelines by presenting a case study from Central California.