FEMA had identified changes along the Black River in Butler County, Missouri since the last modeling and floodplain mapping effort completed in the 1970s. This led them to believe that the current levee in Poplar Bluff was no longer adequate in the event of a flood. This concern instigated a new flood modeling effort which required a hydrographic survey. The project ran from Highway 60 just north of Poplar Bluff, Missouri, to the Arkansas state line.
The hydrographic survey requirements included surveying numerous river cross sections and the primary flow line via single beam echosounder as well as surveying over a dozen car and railroad bridges and numerous drainage structures. Completing the survey required coordination with local authorities such as the local railroad company. To meet FEMA’s requirements, Continental Mapping’s survey team utilized dual frequency GNSS/GPS receivers. RTK corrections were completed using the Missouri Department of Transportation’s Virtual Reference System (VRS). All coordinates were captured to within 5cm accuracy.
The Continental Mapping survey team performed the following:
• Set 6 temporary control points and performed a static GPS survey
• Surveyed 19 river cross sections (water’s edge)
• Surveyed 9 extended river cross sections (top of levee)
• Surveyed the flowline of the river using a single beam echosounder
• Surveyed 11 roadway bridges on the Black River
• Surveyed 3 Union Pacific Railroad bridges
• Surveyed 13 drainage structures along roads, highways and side channels
Butler County, MO Hydrographic Survey