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Monday, January 30, 2017

Coastal Impacts Technology Program: Improving Site Restoration Practices for Oil and Gas Infrastructure Development

Pipeline Construction

Trenching exposes soil layers that become mingled in excavation stockpiles.

Photo Courtesy of Watershed Materials LLC

In a four-year, $4 million effort, The Coastal Impacts Technology Program (CITP), a research initiative of the HARC Environmentally Friendly Drilling Program (EFD) engaged a diverse group of stakeholders to implement a research program to benefit the Texas Coastal Zone. The program focused on addressing environmental aspects of oil and gas operations, including site restoration, air emissions, water resources, and workforce development. Research was funded by revenue sharing from offshore oil and gas operations through the Coastal Impact Assistance Program (CIAP), a multi-year research program authorized by the Energy Policy Act of 2005, administered in Texas by the Texas General Land Office.

The Coastal Impact Assistance Program is a splendid example of revenue sharing from offshore oil and gas activities applied to benefit the environment, economies, and communities of coastal areas.

CITP addressed a comprehensive suite of topics and areas of research need. These efforts yielded invaluable information, tools, and technologies to improve environmental performance and foster conservation, prosperity, and resilience in the coastal areas of Texas. This month’s featured project was carried out by researchers at The Caesar Kleberg Wildlife Research Institute at Texas A&M University – Kingsville under the direction of Dr. David B. Wester, Professor and Research Scientist. The project focused on ways to improve site restoration practices for oilfield projects such as well pad and pipeline construction by studying topsoil stockpiles created during construction activity.

At the outset of construction activity such as well pad preparation or pipeline trenching, topsoil is usually stripped and stockpiled for later use in restoration. During trench excavation, valuable topsoil is usually separated from subsoil material. Even so, the topsoil and subsoil can become mixed, disrupting soil structure. During the time that soil is stored in a stockpile, certain chemical and biological properties favorable to plant growth can become degraded and difficult to restore. Stockpiling also affects seedbanks in ways that can strongly influence the success of subsequent site restoration.

Much like bare soil, stockpiles can be exposed to elevated temperatures and dry conditions. Some of the microbes essential to healthy soil and vegetation may not survive the storage period. Seeds may be rendered inviable and important soil nutrients can be diluted. These changes are influenced by the age and depth of the stockpile. To better understand these dynamics, researchers collected soil samples from stockpiled topsoil at a number of sites over a period of time. The samples were analyzed to characterize the microorganisms and seedbank contained in the soil and how these changed over time.

Seedling emergence and vegetation establishment were studied at more than one hundred test plots along a recently constructed pipeline. The study also examined the fate of native plant seeds and how these are affected by stockpile conditions in an effort sustain seed viability. Information gathered in this research suggests ways in which site restoration can be enhanced by improved stockpiling practices, the use soil amendments, and other measures to mitigate loss of nutrients, improve seed viability, and maintain healthy microbial communities.

The findings of this study are contained in two reports that can be found at the links below::
Final Report: Restoration of Mixed Soils
Final Report: Effects of Age and Depth on Topsoil Properties and Seed Bank Characteristics