The U.S. Army Corps of Engineers has just released the final environmental assessment (EA) for continued maintenance of the Columbia River federal navigation channel.
The maintenance includes placement of dredged material on the eastern shoreline of Rice Island and re-handling material at an in-water site near Howard Island.
USACE will place material on the eastern end of Rice Island located near river mile 22, to rebuild and protect the existing upland placement site.
Placement of dredge material in this area may increase available forage area for streaked horned larks, which were listed as threatened under the Endangered Species Act in 2013.
In-water re-handling of dredged material will take place near Howard Island, located between river miles 68 and 69, because shoaling is consistently forming too far away from the island for a dredge to directly pump that material to the existing upland placement site.
Adding a sump will maximize efficiency of material placement at the existing Howard Island upland placement site.