Who is in charge of the Little Calumet Flood Reduction Project?

For every US Army Corps of Engineers (USACE) project there is a local government partner that signs a Local Cooperation Agreement (LCA) that sets the work and funding responsibilities for the Federal government and the local government partner. USACE has a LCA agreement with the Little Calumet River Basin Development Commission (LCRBDC) signed in August, 1990. Per the LCA, USACE is responsible for the planning, design and construction of this project. LCRBDC is responsible for providing the local share of the funds and securing the required lands, easements and utility relocations to construct the project. In addition, the local sponsor reviews design documents and provides input to the USACE planning and design process. The local sponsor can also request additional project features, known as betterments, which can be constructed at 100% local sponsor expense.

This project is funded by a 75% Federal (USACE) and 25% Non-Federal (LCRBDC) cost share.

The LCA also requires that the non-Federal sponsor operate and maintain the completed project.

What is the function of the Hart Ditch Control Structure?

The Hart Ditch Control Structure restricts flows in the Little Calumet River to the west of Hart Ditch. New project features will increase flows and river stages to the west of Hart Ditch. The Control Structure will retain the increased flows and stages within the set-back levees to the east, rather than pushing those increases to the west. Further, regulatory requirements limit the increase in river levels at the Illinois-Indiana stateline to 0.1 feet.

Why did the project start in Gary and move west?

The East Reach, which is located in City of Gary and the Town of Griffith, includes Phase 1, 2, 3 and 4. The West Reach, which is located in City of Hammond, Town of Highland and the Town of Munster, includes Phase 5, 6, 7 and 8.

If flood protection was not provided in Gary first, the new project features would have increased the damages throughout Gary.

Why are the levees constructed higher than the flood walls?

The levees are designed higher than the required flood elevation to account for settlement within the levees and in the foundation. Over time, the cohesive soils within and beneath the levee will consolidate. The overall estimated settlement is based on the subsurface profiles developed from borings collected in the area and consolidation tests performed on cohesive soils. Calculations for primary settlement and secondary settlement where organic materials were present were calculated along with post-construction settlement of the levee. The overbuild amount varied from location to location due to variable subsurface conditions along the length of the project.

If the project was completed, would it have prevented September 2008 flooding?

It is believed the project would have prevented the flooding of Munster. The September flood event has been estimated to be approximately a 200 year flood, with a 0.5% chance of occurrence in any one year. This project is designed to contain an event of similar to the one that occurred in September. All USACE constructed levees functioned within the design parameters and there were no failures or overflows of the project.

Why do we leave roads (bridges) that are lower than the levee height?

Road relocations are not part of the authorized project. State and local entities own these roads, operate, and maintain them. The project does include closure gates or sandbag closure structures, to provide acceptable flood protection at road closures and bridges. Closure options were evaluated for each road crossing, and the most feasible alternative was selected for each of the road crossing locations within the project area. All restrictions to flow, including bridges, are factored into the design of this project.

The local entity can raise the roads or bridges, at their expense, if it is their wish to eliminate the road closures. A number of bridge replacements/raises have taken place during the project construction, including bridges at Grant Street, Burr Street, and Hohman Avenue.

What impact does Hart Ditch and Deep River have on the flow of the Little Calumet River?

Hart Ditch is the primary source of floodwaters during flooding events in the project area. High flows on Hart Ditch raise river levels very quickly on the Little Calumet River during a flood event. Also, due to manmade features in the Little Calumet River Watershed (Hart Ditch, Cady Marsh Ditch and Burns Ditch), flows split to the east and to the west of Hart Ditch on the Little Calumet River, thus extending the impact of flows from Hart Ditch along a large portion of the river.

Under flood conditions, Deep River backflows into the Little Calumet River through the control culverts at the Penn Central RR bridge. This backflow causes an increase in river levels in the east, as well as restricting the flow from the east end of this project out Burns Ditch and then into Lake Michigan.

Why did Gary (including the Indiana University) flood during the September 2008 flooding?

While some flooding on the landside of the levee can be expected during large storm events due to interior drainage issues, the flooding in Gary during the September flood event was more severe than expected. The effectiveness of the flood protection system in Gary appeared to be compromised from two different issues. Road closure sections (where roadways cross the levee system below the top of the levee) were not closed according to the operations plan. In addition, floodwaters appeared to have entered sewer lines on both the landside and riverside of the levee system. The sewer network transmitted the floodwaters throughout the area behind the levee system.

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