Installation, Operation, and Performance of the Gunderboom® Marine Life Exclusion System at Cooling Water Intakes

Electric utilities and other industries that withdraw water for cooling purposes are under increasing pressure from state and federal regulatory agencies to reduce losses of fish due to entrainment and impingement.  New draft regulations from USEPA scheduled to be published in March 2011 may require reductions in losses of 80% or more.  The Gunderboom Marine Life Exclusion System™ (MLES™), a full-water-depth filter barrier that effectively limits aquatic biota from entering cooling water intake structures may provide such reductions. The technology was developed during a six year (1995-2001) research and development program conducted at the Lovett Generating Station, having a once-through flow of 465 MGD and located on the lower Hudson River.  Seasonal deployments, scheduled to coincide with the presence of fish eggs and larvae, were used to develop and improve the technology. Resulting design changes increased the flow- through capacity of the fabric, and incorporated an automated Air-Burst™ cleaning system, and improved anchor system that allowed operation of the MLES™ under extreme flow and weather conditions.  Ichthyoplankton monitoring was conducted during the program to measure the system’s effectiveness at reducing entrainment. Paired samples were collected at protected (i.e. within the MLES™) and unprotected intakes during 1995, 1998, 2000 and 2004 through 2007. Results from the ichthyoplankton monitoring program indicate that the Gunderboom MLES™ was greater than 80% effective at reducing entrainment.  Results of the monitoring studies are discussed along with some specialized studies to measure the potential for impingement of organisms on the filter fabric.  These studies have potential implications for other technologies as well, such as fine slot wedgewire and travelling screens.  Effectiveness of the filter fabric technology is compared to other technologies and a current installation of the MLES™ on the Taunton River in MA, in its fourth year of operation, is described.