Environmental Assessment. Dredged Material Thalweg Placement Site Mississippi River Miles 561.0 - 561.4 Island 241, Pool 12.

摘要

Island 241, located approximately midway between Lock and Dam 12 and Galena, Illinois, has recently become a significant shoaling area. As a result, dredging has been needed to keep that portion of the channel open for navigation. Since 1984, this area between River Miles (RM's) 561.7 and 562.3 has required two dredging events (1984 and 1990). Over that time, sedimentation in this area has necessitated that removal of over 150,000 cubic yards (cu yd) of dredged material, with each dredging event averaging approximately 76,000 cu yd. The location that is currently in need of dredging is approximate RM's 561.8-562.2 (plate EA-1).