UPLAND/INLAND SPILL RESPONSE: USE OF UNDERFLOW DAMS

Abstract

ABSTRACT On December 20, 1999 at approximately 1045 hours, crude oil was discovered in the Leaf River near Collins, Mississippi. The investigation determined the discharge was approximately 8,000 barrels originating from a source in the vicinity of State Highway 28 and Summerland Road, Jones County, Mississippi. The point of the release was located inland and in an upland type environment approximately 8 miles from the discovery location (Highway 84 bridge) near Collins, Mississippi. After the line was shut-in and control of the source was certain, it was determined there were three distinct types of work areas remaining for the cleanup operations: an upland marsh type environment, an ephemeral flow creek bed, and a limited access river environment. Strategic objectives for the response included prevention of any further migration of oil down the Leaf River; and prevent any additional oil from migrating or being flushed (during the next rain event) out of the upland marsh area down the unnamed creek and entering the Leaf River. The focus of this paper is on the measures pursued by operations and the Unified Command that were designed to prevent any further oiling of the Leaf River in the event oil was flushed out of the upper marshy area as a result of the cleanup operations or from a rain event. Operations installed a series of underflow dams at the confluence of the unnamed creek and the Leaf River as well as between the unnamed creek and the upland marsh area. These two stopgaps provided the necessary containment for the anticipated rain events forecast to occur early in the new year. The series of dams were successful in controlling the total fluid flow, containing flushed oil, and preventing additional oiling of the Leaf River during the first rain and throughout the remainder of the response.