Coastal Subsidence Conference Attracts Diverse Forum
by Arthur E. Berman, photos by Matt Kolodney
More than 120 people attended the “Coastal Subsidence, Sea Level and the Future of the Gulf Coast” conference November 3–5 to hear differing views on the risks of subsidence for coastal areas of Texas and Louisiana including Houston.
The Houston Geological Society and the Engineering, Science and Technology Council of Houston (ECH) joined together to organize and present the meeting at the Northwest Conference Center in Cypress, Texas. The goal of the conference was to provide a forum where differing parties could present their positions and potentially come to consensus on what action would be appropriate for Texas.
Keynote Speaker Dave Zilkoski of the NGS
The HGS and ECH organized the meeting to increase public and governmental awareness of the complex issues involved in subsidence and to provide a forum for discussion of all aspects of the subsidence issue. The hope was to open lines of communication so that policy makers, their technical advisors and the public might have a better understanding of coastal subsidence, how to quantify and predict it, as well as plan infrastructure around its effects.
These were perhaps idealistic expectations considering the fundamental differences dividing the various parties in the subsidence debate for the Gulf Coast. While everyone involved in the debate over subsidence agrees that there are many aspects and factors that contribute to subsidence, there clearly are also camps that favor a single cause as being the most significant.
Keynote Speaker Virginia Burkett, USGS
The Harris Galveston Subsidence District (HGSD) represents the strongest voice favoring ground water withdrawal as the chief cause of subsidence in the Houston area. Changes in ground water pumping directed by the HGSD have resulted in impressive reduction or elimination of subsidence in low-lying areas of Houston. There are, however, portions of the metropolitan area that are undergoing significant subsidence that is not easily explained or fully understood.
The other pole in the subsidence debate is represented by Dr. Roy Dokka, professor at Louisiana State University and co-author of the 2004 Technical Report NOS/NGS 50, “Rates of Vertical Displacement at Benchmarks in the Lower Mississippi Valley and the Northern Gulf Coast.” Dokka’s report concludes that rates of subsidence in southern Louisiana are significantly greater than previous estimates and that modern subsidence includes a tectonic component. HGS members may recall that Dr. Dokka addressed an HGS General Luncheon Meeting held jointly with the Society of Petroleum Engineers (SPE) in November 2004 on “Anatomy of a Silent Disaster: Ongoing Subsidence and Inundation of the Northern Margin of the Gulf of Mexico Basin.”
The diverse array of participants at the Coastal Subsidence Conference included state and local government and regulatory officials from Texas and Louisiana, representatives from various federal agencies such as the National Oceanographic and Atmospheric Administration’s (NOAA) National Geodetic Survey (NGS) and National Hurricane Center, and the United States Geological Survey (USGS). The conference was also attended by university researchers and faculty from the University of Texas, Texas A&M University, Rice University, University of Houston, Tulane University and Louisiana State University (LSU), along with representatives from a variety of geological, environmental, petroleum and engineering companies.
The first day of the three-day conference was devoted to understanding coastal subsidence, the methods used to measure subsidence and techniques used to evaluate the contribution of ground water withdrawal, oil and gas production, engineering projects and geological factors to the overall subsidence budget. The second day addressed the economic and cultural effects of subsidence and the results of mitigation efforts, options and consequences. A field trip on the third day visited sites of active faulting and subsidence within the Houston area.
Conference leadership team (left to right): Front: Glenn Carlson (ECH) and Cheryl Desforges (HGS). Rear: Dave Rensink (HGS) and Art Schroeder (ECH)
HGS President Dave Rensink began the conference Wednesday morning and gave a keynote address that afternoon titled “An Introduction to the Origin of the Gulf of Mexico and Its Role in Subsidence.” Other keynote addresses included Dave Zilkoski of the NGS on “The Importance of an Accurate Subsidence Network for the Establishment of Vertical Control and Subsidence Rates,” and Virginia Burkett of the USGS on “Subsidence and Future Relative Sea Level Rise in the Gulf Coast.”
Guest speakers included Sam Webb, Deputy Commissioner for Coastal Resources Program, Texas General Land Office, who discussed “Coastal Subsidence: Finding Common Ground”; John Anderson of Rice University, whose topic was “Long-Term Subsidence Along the West Louisiana and East Texas Coast”; and Ron Neighbors, HGSD, who spoke on “The Politics and Public Policy Issues of Subsidence.”
HGS President Dave Rensink described the purpose of the conference. “The idea is to expose participants to as many of the cause and effect relationships of subsidence as we possibly can. We want to make sure that everyone who is involved in the decision-making process is considering as many aspects of the problem as there really are and not focusing on only one or two aspects of the problem.”
Roy Dokka added to Rensink’s comments. “I think society needs to understand what that risk is. It needs to be honest with people who live there saying, here’s the potential. There is no guarantee in life. We can’t guarantee anything. What we can do is to see what may happen. Public officials that have responsibility for these things need to understand them and then express them to the community so that the people who live there also understand. Geological insights are too important to be left just to geologists.”
It is safe to say that most attendees were aware that subsidence is a problem for coastal regions of the Gulf of Mexico. Probably not all were equally aware of the complexity of the issue. Most participants agreed that the conference was successful in raising awareness that coastal subsidence cannot be easily explained in terms of one cause or factor.
Meeting organizers w