The U.S. Army Corps of Engineers’ dredge Murden arrived in Martin County Aug. 1 to dredge a problematic shoal creating a safety concern within the Crossroads reach of the Intracoastal Waterway (IWW). The Corps requests recreationists slow down and use caution in this construction area. The Crossroads reach is where three federal channels come together -- the IWW, the Okeechobee Waterway and the St. Lucie Inlet.