Phillips 66 Pipeline, LLC (P66, Requester) in Cowley County, Kansas, is proposing to replace a segment on its existing pipelines under the Arkansas River and adjacent Arkansas City Levee and within US Army Corps of Engineers (USACE)-administered fee lands at the Kaw Lake Project (Figure 1), which is under the Jurisdiction of the USACE. The 10-inch diameter pipelines that carry petroleum products were installed circa 1920s and 1950s.