High Water Note:
At 38 SLG the U.S. Coast Guard will consider closing the St. Louis harbor to navigation.
Major Flood Stage: 40
Moderate Flood Stage: 35
Flood Stage: 30
Action Stage: 28
Water Levels and Dikes
In the St. Louis area you can use the following scale to gauge water flowing over dikes, although some dikes vary in height. Also some have been “notched” in recent years as result there will be a middle notch that you can paddle through at much lower levels of water, some places down to 0 St. Louis Gauge.
Using the St. Louis Gauge:
10-12 SLG water flowing through notches only
13 SLG - rocks still exposed on all dikes
14-15 SLG dikes starting to go under, some flow through breaks & low spots
16 SLG dikes completely under, but little flow
18-20 SLG good flow and lots of boils & turbulence
22 SLG strong flow, some turbulence, no dikes exposed anywhere
25 SLG river bank full
>30 SLG Flood Stage
Warning: above 30 SLG paddlers are advised to stay off the river. Limited access. Most landings and approach roads will be underwater. Most islands will be gone. No easy camping. All sandbars will be covered. Fast waters with many hazards. All islands and landings will be surrounded by flooded forests full of snags, strainers, sawyers and all other dangerous conditions associated with floodwater moving through trees. Docks, wharves, dikes and any other man-made objects will create strong whirlpools, violent boils, and fast eddies. Towboats will create large waves. The Rivergator will not describe the river and its islands at any levels above flood stage.
Flood Stage effects in St. Louis
Just to give some perspective on how various water levels effect different places along the river in the greater St. Louis area, here are some descriptions of levees and floodgates from the NWS.
At 18.5 Riverfront parking east of Leonor K. Sullivan Boulevard begins flooding (which means reduced parking places below the arch. Paddlers can make landing until flood stage. 30 Floodwall at Lacledes Landing is closed. At 31.7 Leonor K. Sullivan Bouelvard begins flooding at this level in front of the Arch. At 31.9 The entrance to the parking garage just north of Eads bridge begins flooding. At 32 the flood panels at Carr Street and Poplar Street are installed. 33 the Floodgates at the Rutger Street railroad and at Miller Street are closed. At 34 the Floodgates at Convent Street railroad and Rutger Street are closed. At 35 Moderate flooding begins. The floodgates at Gratiot Road railroad and Choteau Street are closed. When the river hits 37 SLG three more floodgates are closed at this level: the Missouri Illinois Sand Company gate in south St. Louis, the City of St. Louis railroad gate, and a double gate at East Grand in north St. Louis. At 37.5 Highway 61/67 south of Pevely begin flooding at the Joachim Creek bridge. At 38 The U.S. Coast Guard will consider closing the St. Louis harbor to navigation above this level. Four more floodgates are closed at Prairie Avenue, Madison Avenue, Mullanphy Street, and the railroad bed near Lesparance Street. At 38.5 Nellie Avenue, south of Lemay Ferry Road along River des Peres, begins flooding. At 39 the city of Kimmswick, MO begins flooding. Two more St. Louis floodgates are closed at North Market Street (north St. Louis) and at Barton Street on the south side. 39.1 Windsor Harbor Road bridge southeast of Kimmswick begins flooding, isolating residents south of the bridge. Major Flood Stage begins at 40 SLG. At this level the Choteau Island Levee, protecting 2400 acres, is overtopped. Lemay Park just south of Lemay Ferry Road will begin flooding. The St. Louis Metropolitan Sewer District will shut down the Watkins Creek pump station in the 11000 block of Riverview Drive in Spanish Lake. At 41 St. Louis City installs a double floodgate at Branch Street in north St. Louis. At 42 Riverview Blvd becomes flooded. A panel floodgate is installed at Riverview Blvd. At 43 At this level, 5 floodgates are installed: 3 floodgates at the Corps of Engineers Service Base, another at Zepp Street, and another at the railroad near Guthrie Street. At 44.1 the Chouteau Island Pump Station begins to flood. Power to the Chouteau Island Pump Station disconnected. The Harrisonville and Columbia Levees are overtopped. At 47 The panel floodgate is installed at the CB&Q railroad. Businesses along North Commercial Street in Laclede's Landing in downtown St. Louis begin flooding. At 47.7 The Columbia Bottom levee is breached which protects 14,000 acres. At 48 The Harrisonville and Prairie DuPont levees which protect 37,360 acres is breached. At 49 Hartford Public Water supply is threatened. The last of the St. Louis City floodgates is installed at the Missouri-Pacific railroad (panel gate). At 54
The Metro East St Louis and Fish Lake levees which protect 71,000 acres are overtopped. Also at this height the St. Louis flood wall is overtopped.
The Great Flood of 1993
The Mississippi River crested in St Louis at 49.58 feet during the The Great Flood of 1993 (August 1st). All of the towns downstream have their own highwater marks and many stories and dramas from the 1993 Flood. Mark River remembers returning to St. Louis that watershed year:
“In between football tryouts in 1993, I had the opportunity to fly back to St.Louis and observe the infamous flood. Growing up between the confluence of two great rivers and downtown St. Louis, I was anxious to see what the Mississippi River looked like when it reclaimed its natural floodplain. I wasn't disappointed: the river reached to the bluffs. Riverview Drive was closed and only locals in that area were aloud to access the neighborhood by john boats and canoes. Looking from the bluff on which Missouri Portland Cement rests, you could see the vast natural floodplain. Mosenthein Island was underwater with just the tops of the largest trees exposed with its back channel not distinguishable. The Chain of Rocks low water dam was unrecognizable. The confluence of the Missouri and Mississippi Rivers was a wild ocean-like area with displaced farms and equipment scattered throughout. The field in which I grew up practicing football was underwater. The golf course which graced the land below the 270 bridge was wiped out. Deer and other mammals were pushed into the neighborhoods, flooding the streets at night. Accidents skyrocketed along the roadways. Local fisherman took advantage of the incredible flood. The fish went on a spawning frenzy, moving up the streams and creeks making themselves accessible to anglers. People were catching lunkers out of their backyard creeks. Hand fisherman were crawling through the shallow streams pulling catfish out of logs and other obstructions. Waterfowl filled the shallows feasting on newborn fry.
“As the water receded, new gravel beds were exposed and sandbars reappeared in unusual areas. Small depressions within the landscape were full of fish. Locals in gallowses and waders pulled huge buffalo and grass carps out of these depressions. Many farmers relocated after the flood. Selling their properties and looking for land in higher elevations. Years afterward when the floodplain dried out, the land close to the confluence was purchased and made into a state park. The surrounding lands were left alone to return to its natural state. The golf course was never restored. A lot was learned from this historical natural event and was a lesson in how important the floodplain is to our natural environment.” (Mark River)