Wednesday, November 24, 2010

NGS Participates in Cooperative Effort with USGS and Harris-Galveston Subsidence District

On November 18, the Harris-Galveston Subsidence District in Friendswood, TX, began collecting data at a new Continuously Operating Reference Station (CORS) located at the Clear Lake Borehole Extensometer near the Johnson Space Center. Borehole extensometers are deeply anchored benchmarks. The Clear Lake Extensometer is the deepest in the Houston region at 3,072 feet. It’s also the most stable benchmark in the area. The new CORS will improve the subsidence-monitoring capabilities in the area and provide for improved surface modeling and accurate height determination in an area where conventional benchmarks can quickly be rendered invalid by subsidence due to surface dynamics. The project is a cooperative effort involving the National Geodetic Survey (NGS), Harris-Galveston Subsidence District, and the U.S. Geological Survey. Once sufficient data is collected and analyzed, it will be submitted to NGS for consideration as a National CORS. For more information, contact Cliff Middleton.