Flooding

One of Semo Port's advantages is the fact that its facilities are new, modern, and designed to operate even during times of high floods. As a standard, they are designed for a 500-year flood (elevation 354.9), or three feet over 100-year level. The floods of 1993 and 1995 did not reach the 100-year level: the highest water elevation was 351.33 in 1995, versus the 100-year flood elevation of 351.8 feet above sea level.

Highways.  The highways serving Semo Port are completely above 500-year flood elevation. This includes Interstate 55, Route AB, and Route K through Scott City. Route AB was opened to traffic in October 1997, and over a mile of it is built on a fill (20 feet tall) for flood protection.

Railroads.  The Semo Port Railroad (SE) is above the 500-year flood in the Port's harbor industrial area and southward to the Union Pacific Railroad connection at Capedeau Junction MO (east of Scott City MO). Service is available with UP at any recorded flood stage.

The Burlington Northern Santa Fe Railway (BNSF) and the SE's line northward to the BNSF at Cape Girardeau MO both close at a 40 gauge. When such a closure occurs, it typically is only for a few days. If necessary, BNSF traffic to/from Semo Port can be rerouted via UP.

Utilities.  Utilities in the Semo Port area are designed to accommodate a 500-year flood. This applies to electric power lines and substation, natural gas line, water lines, sanitary sewer system, and telecommunications.

Terminals.  Semo Port's modern terminal facilities are designed to minimize or alleviate the effects of flooding. During the floods of 1993 and 1995, barges were worked on an emergency basis even though the river was temporarily closed to navigation. Most of the barge facilities at the Port can operate at the highest flood stages (Consolidated Grain, Midwest AgriChemico, First Missouri Terminals). Additional locations around the harbor are suitable for emergency use when needed.

The general cargo dock (Girardeau Stevedores and Contractors, GSC) has an elevation of 345 and closes at a Cape gauge of 44. It was designed to be open at any time the river is open to navigation. Typically it is closed less than one percent of the time. For the unusual times it is closed by extreme flooding, work is diverted to other locations around the harbor. The Old Dock has an elevation of 330 and closes at about 28 gauge.

Reference
River Levels During Flood and Drought Conditions

At Semo Port, the floods of 1993 and 1995 were below the 100-year flood elevation. All new facilities (streets, railroad tracks, building sites) are built above the 500-year elevation. The reference elevations and historical river levels are:

High Level: elev 354.9 500-year flood elevation

elev 351.8 100-year flood elevation

elev 351.33 level on 5-24-95 (Cape gauge 46.7, with Ohio River over flood)

elev 351.15 level on 8-07-93 (Cape gauge 48.2, with Ohio River low)

Low Level elev 307.39 Corps of Engineers Low Water Reference Plane

elev 306.07 level on 12-27-89

elev 305.00 harbor design low water level for 9' draft

elev 296.00 harbor design bottom
  

 

Reference
River Gauge & Elevation

This table converts from Cape Gauge to Semo Port Elevation (Corps of Engineers).

Cape Girardeau, MO
River Stage
Approximate Elevation
NGVD Mile 48.0
0 302.6
10 311.9
20 321.9
30 331.9
40 341.6
50 351.0