Project Images Monarch-Chesterfield Levee flood-wall design Project Summary The Monarch-Chesterfield Levee was constructed to protect the city of Chesterfield, Mo., (near St. Louis) and adjacent communities from flooding caused by the Missouri River and one of its tributaries. The Great Flood of 1993 inundated the Midwest. More than 1,000 levees failed, 70,000 buildings suffered damage, and 50 people died. Damages totaled at least $12 billion. On July 30, 1993, at 10:17 p.m. the surging Missouri River ruptured the 100-year Monarch-Chesterfield Levee. Flood waters spilled through a 100-foot section of the levee, filling the entire Chesterfield Valley with more than 8 feet of murky flood water and debris. In 1994, work began to raise the levee’s flood protection by increasing the height of the levee 3 to 6 feet, widening it, and adding seepage berms, gates and flood walls. Although several dozen businesses abandoned the area for higher ground after the devastating flood, others chose to remain. The city of Chesterfield created a tax-increment financing district to rebuild the levee and revitalize the area. As a result, Chesterfield Valley has become one of the region’s hottest retail markets, and its success has spurred other cities to develop their flood plains. The Great Rivers Greenway District’s system of parks, open spaces and trails will reconnect people in the region with the little-known features and resources that exist along the Missouri River corridor. The Monarch-Chesterfield Levee Trail is important to the city’s parks, recreation and trails system. In addition, the Monarch-Chesterfield Levee District sponsored a 130-acre wetland mitigation project which created wetland sites in Chesterfield, along the Missouri River. The project took two years to complete and has been monitored for several years to assess the success of the wetlands. Hanson is currently providing engineering services for the next phase of this project which is the design and construction of a flood wall. Hanson is participating in the design, preparation of plans and specifications, and material quantities and construction cost estimate for a pile-supported reinforced-concrete T-type flood wall, appurtenances and all civil site improvements. The north end of the flood wall will tie into an existing railroad closure structure. The south end of the flood wall will tie into Long Road which will be improved by St. Louis County as part of a major intersection and highway realignment, bridge replacement, and creek improvements project. The planned flood wall is part of the Monarch-Chesterfield Levee District flood-protection system of Chesterfield Valley from the Missouri River and a tributary, Bonhomme Creek. This work is being performed as a consultant to small business Maurer-Stutz under the District’s AE Indefinite Delivery Indefinite Quantity Contract. Hanson also provided surveying to aid in the design and acceptance of this levee. Hanson surveyors provided horizontal and vertical project control, aerial mapping control, quality assurance test surveys, topographic surveys, profiles and cross sections and volume computations.