Gauges and Navigation Lights

Gauges and Navigation Lights. Mississippi River Walk. Early Mississippi river pilots depended on their instincts and on weighted lines thrown overboard to judge the water's depth. Natural landmarks were the only guides for safely steering the channel. Night travel was impossible in low water. Gauges and navigation lights began appearing in the 1870's, after Congress took charge of river navigation. , The U.S. Army Corps of Engineers monitors and maintains several gauges along the Mississippi River. The innovative technology of modern towboats; such as, fathometers, radar, and GPS systems, make the gauges less essential today, but tradition-minded pilots have resisted their removal. The boards show current river level and an "R", "F", or "S" to indicate whether the level is rising, falling, or steady. The Memphis gauge board can be seen high on the bluff just north of Beale Street, southeast of Mud Island River Park. A second gauge on the Memphis side, under the bridges south of Mud Island River Park, automatically displays the river stage to passing tows. Zero on the Memphis gauge, indicating 15" average channel depth, is set at 183.91 feet Mean Sea Level. , The river's first navigation lights were coal oil lanterns, tended by private citizens who braved the elements to keep them burning. Each light had a name, such as Hanging Dog, Robinson Crusoe, and Quaker Oats. Today the U.S. Coast Guard maintains navigation lights and markers on the river. The battery powered lights are mounted on white platforms, and backed with large white "X"'s to insure daytime visibility. A sign on each platform shows its exact mileage position for pilot reference. The lights are moved to adjust to minor charges on the river, and charts are regularly updated to reflect these changes.