- Why did the project start in Gary and move west?
- Why are the levees constructed higher than the flood walls?
- Who is in charge of the Little Calumet Flood Reduction Project?
- What is the function of the Hart Ditch Control Structure?
- What impact does Hart Ditch and Deep Run have on the flow of the Little Calumet River?
- Why do we leave roads (bridges) that are lower than the levee height?
- If the project was completed would it have prevented last September flooding?
- Why did Gary (including that Indiana University) flood during the September flooding?
- What is the history and status of the four houses west of Hohman Avenue?
- What is a betterment?
- Silt has been building at the Northcote and Colombia bridges causing a water jam. What is USACE doing to eliminate this problem?
- Why is Stage VIII (Southmoor Road Area) necessary?
- This is a twenty year project that should be revised to today's improvements. When were the economics and the hydraulic modeling updated?
- On the South side of the river between Jefferson and Jackson, what does the design of the levee ential? Can I see this information?
- Will the temporary levee material provided by the town of Munster be removed or left in place?
- Will the soil conditions under the levee in this area be consolidated or improved?
- Will the flow restrictor at Northcote overflow in a flood? If so what is the purpose of this structure?
- One would expect the flow of the river to be greater downstream, i.e., Gary than upstream i.e. Hammond and Munster, because of additional flow into the river. Why is the area under the bridges at Calumet, Northcote, Indianapolis, Kennedy and Burr so much greater than at Chase, Grant, Broadway and Georgia?
- Do the Towns and Cities along the river have the construction drawings and design information for their portion of the project? Will the ACE provide protection in hte event of flooding before the levee is complete?
- What plan is in place for March or the spring of this year, when the ice on the river starts piling up at the bridges and other restrictions, and we have snow melt, saturated ground, high rains and flood conditions?
- If none, why did we spend so much money on a project that does not meet its objectives?
- Does the NOAA level gauge at Munster base flow on actual flow measurements or by calculation based on depth?
- Based on the current height ("reveal") of the sheet piles, why does it appear that Stage 8 will have more flood protection than Stage 7?
- Of "all the earthen levees" designed by ACE, not counting piled and concrete levees, built to EM 1110-2-1913 since 2000, when the manual was revised, how many earthen levee failures have there been? How many piled and concrete levees have failed?
Question: Why did the project start in Gary and move west?
Answer: 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.
Question: Why are the levees constructed higher than the flood walls?
Answer: 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.
Question: Who is in charge of the Little Calumet Flood Reduction Project?
Answer: For every US Army Corps of Engineers (USACE) project there is a local government partner that signs a Project Cooperation Agreement (PCA) that sets the work and funding responsibilities for the federal government and the local government partner. USACE has a PCA agreement with the Little Calumet River Basin Development Commission (LCRBDC) signed in August, 1990. Per the PCA 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 land, easement and utility relocation 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 PCA also requires that the non-Federal sponsor operate and maintain the completed project.
Question: What is the function of the Hart Ditch Control Structure?
Answer: 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.
Question: What impact does Hart Ditch and Deep Run have on the flow of the Little Calumet River?
Answer: Hart Ditch is the primary source of floodwaters during flooding events in the is 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.
Question: Why do we leave roads (bridges) that are lower than the levee height?
Answer: 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.
Question: If the project was completed would it have prevented last September flooding?
Answer: 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.
Question: Why did Gary (including that Indiana University) flood during the September flooding?
Answer: 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 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.
Question: What is the history and status of the four houses west of Hohman Avenue?
Answer: Feature Design Memorandum 5 (FDM 5) recommended that the 4 four homes west of Hohman Avenue on River Drive should be purchased and the families relocated at project expense During the completion of FDM 5, concerns were raised by the Town of Munster about emergency access to the four residences during a 100-year or less frequent rainfall event based on the potential for inundation of River Drive, which has an approximate elevation of 595.4 (feet NGVD). Consequently, the recommendation was made, in concurrence with the local sponsor, to include a buyout of those four homes in the flood control project.
In the early development process of the Stage VIII Plans and Specifications, the Little Calumet River Basin Development Commission staff requested that we re-evaluate the USACE FDM 5 recommendation because of the large costs involved. USACE re-evaluation was documented in a letter dated February 8, 2002 to Dan Gardner, Executive Director of the LCRBDC and in which USACE left the final decision for the buy out to the Commission and the local community of Munster.
Question: What is a betterment?
Answer: The Non-Federal Sponsor (LCRBDC) may request the Government (USACE) to accomplish betterments. Such requests shall be in writing and shall describe the betterments requested to be accomplished. If the Government in its sole discretion elects to accomplish the requested betterments or any portion thereof, it shall so notify the Non-Federal Sponsor in writing setting forth any applicable terms and conditions, which must be consistent with Local Cooperation Agreement (LCA). The Non-Federal Sponsor shall be solely responsible for all costs due to the requested betterments including the costs of any additional lands, easements and rights-of-way required solely for the betterments, and shall pay all such costs.
The local sponsor (LCRBDC) can request deviations to the approved USACE Plans and bear 100% of the additional cost. Such requests can be finding alternative ways to expedite the construction which may result in increasing the construction cost. The additional cost would have to be borne by the LCRBDC. Example of betterment requests are the construction of the Burr Street Levee in place of the approved authorized plan to implement the none-structural measures, flood proofing individual structures instead of flood proofing an entire area.
Question: Silt has been building at the Northcote and Colombia bridges causing a water jam. What is USACE doing to eliminate this problem?
Answer: Bridges in general do have some impact on the river flow and stages. Sometimes the impacts will be negligible, whereas in other cases, the impacts will be significant. These impacts are dependent on many factors. The hydraulic impacts of the Northcote Avenue and Columbia Avenue bridges have always been taken into account in the design of the Corps of Engineers Little Calumet River Project.
The scope of Little Calumet River Project does not include bridge and channel modification work at the Northcote and Columbia Avenue bridges or other bridges. Any modifications to the channel beneath these bridges are the responsibility of the local governments that own the bridge.
The State of Indiana Department of Natural Resources - Division of Water performed a survey of observed high water marks after the August 2007 flood on the Little Calumet River. These high water marks included four taken in the vicinity of Northcote Avenue (no survey was taken at Columbia Avenue). These surveyed high water marks indicate very little stage difference (head loss) across the Northcote Avenue Bridge during the peak of that historic flood event. The result of the survey confirms our hydraulic model which indicates a similar difference in head loss across the bridge for the design event. Which indicates that the impact is negligible a sizable head loss would be an indicator of an obstructive bridge cross section.
If there is access of silting local government can remove excess silt (dredge) by obtaining the required permits from local state agencies and USACE, Detroit District (which has the regulatory function for North West Indiana). Removing silt will improve the flow of water under normal flows and smaller flood events.
Question: Why is Stage VIII (Southmoor Road Area) necessary?
Answer: The floodwall alignment in the Southmoor area was located closer to the river where ground elevations are lower, in order to minimize impact to existing landscaping and structures. The ground elevation at the base of the floodwall ranges from approximately 594 feet NGVD to approximately 598 feet NGVD. The floodwall averages a height of approximately 4 ft in the Southmoor area with a maximum height of approximately 7 feet near Hohman Avenue due to the lower ground elevation. The floodwall extends 24 feet below the crest in the Southmoor area. The length of sheet pile below grade was designed to insure the structural stability necessary to withstand the pressure of flood waters to the top of the wall.
Several members of the Chicago District’s Staff met with Dr. Roy Evans (Independent Engineer representing the Southmoor Area) on July 11, 2008 to answer questions and address his concerns. A set of the Stage VIII final plans and a copy of the Feature Design Memorandum 5, which was the basis for Stage VIII design were provided to Dr. Evans. Dr. Evans wrote a letter to the Little Calumet River Basin Development Commission in which he outlined his concerns. The Chicago District provided responses to the Commission to address Dr. Evans remaining concerns. The Chicago District staff believes that his significant concerns have been addressed, and does not believe that further evaluations are necessary.
The Southmoor Area Residents requested a review of the Little Calumet River project from Hohman Avenue to Lyman Avenue in accordance with Section 2034 of the Water Resources Development Act of 2007. Section 2034 of the Water Resources Development Act of 2007 addresses the peer review requirements for Corps of Engineers Project Studies. The Little Calumet River Flood Control and Recreation Project was authorized in the Water Resources Development Act of 1986. The study phase of the project ended with project authorization, consequently, the new WRDA requirements do not apply to this project. The project is in the construction phase. During the construction phase, the Chicago District completed Feature Design Memoranda, which were reviewed and approved by the North Central Division of the Corps of Engineers. The Chicago District is currently completing plans and specifications for specific project reaches or elements, which are then constructed.
Question: This is a twenty year project that should be revised to today's improvements. When were the economics and the hydraulic modeling updated?
Answer: The Illinois State Water Survey reviewed the model and used our latest version of the model (2005) to remap the FEMA floodplain in Illinois. The new FEMA floodmaps based on the model became official in August 2008. The same model has been reviewed by Indiana DNR and was approved in 2007 as acceptable for the FEMA remapping in Indiana. An independent technical review was conducted on the model by an unsteady flow modeling expert at the Corps' Hydrologic Engineering Center in 2005 and it was approved. The model is currently being used by Burke Engineering of Indianapolis for the FEMA flood remap package they are submitting to FEMA for the remapping of the City of Hammond between Northcote Avenue and Cline Avenue.
An economic update of the entire project was performed in 1999 based on changes to the overall project. A district economist reviewed and updated benefit computations associated with the reduction in flood damages that would be provided by the project. The project was found to still meet Corps requirements (benefits greater than costs). The analysis considered the reduction in damages to residential and commercial structures, and the transportation infrastructure (roads and highway) from flooding, that could be attributed to the project. The economic update was reviewed and approved through the Division Office. As we are approaching completion of this project, the Chicago District does not believe another economic review of the project is necessary or appropriate.
The current design analysis, including the hydrologic and hydraulic modeling used to develop the design water levels, does include the recently constructed Thornton Transitional Reservoir in Illinois. As is evident from the September 2008 flood on the Little Calumet River, massive flooding still occurs even with the Thornton Reservoir (Deep Tunnel and Reservoir Project) in place. Although the Thornton Reservoir will be expanded in the future, the flood storage reserved for the Thorn Creek Diversion will not be increased and the future expansion will not provide additional flood damage reduction for the Little Calumet River. The additional expanded storage is reserved for the Deep Tunnel system.
Question: On the South side of the river between Jefferson and Jackson, what does the design of the levee entail? Can I see this information?
Answer: All levees for this project are designed in accordance with the requirements of engineering manual EM 1110-2-1913 Design and Construction of Levees dated 30 April 2000. An online copy of the manual can be obtained at the following link: click here.
Yes, you can view the LCR Stage 8 Design Analysis.
Question: Will the temporary levee material provided by the Town of Munster be removed or left in place?
Answer: The temporary levee material placed by the Town of Munster will be removed as necessary to construct the new levees and floodwalls in accordance with the requirements of the contract plans and specifications. The contract does allow the contractor to remove and reuse any existing materials that meet the contract requirements for new levee fill.
Question: Will the soil conditions under the levee in this area be consolidated or improved?
Answer: The contract requires the contractor to excavate an inspection trench that has a minimum depth of 6 feet along the entire alignment of the new levees. The purpose of the inspection trench is to remove and inspect existing soil conditions under the new levees. If any soil conditions are found to be unsatisfactory for the new levee foundations, they will be improved and/or replaced as determined necessary by Corps of Engineers personnel in the field.
Question: Will the flow restrictor at Northcote overflow in a flood? If so what is the purpose of this structure?
Answer: The Hart Ditch Control Structure does not overtop during the design flood event.
"The Hart Ditch Control Structure consists of a constriction to regulate flow to the west. The structure will limit westerly flow such that the flows and stages at the state line will not increase more than allowed under Illinois floodplain regulation." (Quote is from the COE Phase II General Design Memorandum)
The intended purpose of the Hart Ditch Control Structure is not as much for flood reduction as it was for regulatory mitigation at the state line, however, it does provide approximately three inches of stage reduction at the state line during the design flood.
Question: One would expect flow of the river to be greater downstream, i.e. Gary than upstream, i.e. Hammond or Munster, because of additional flow into the river. Why is the area under the bridges at Calumet, Northcote, Indianapolis, Kennedy and Burr so much greater than at Chase, Grant, Broadway and Georgia?
Answer: This logic is correct when applied to net volume of flow passing Broadway as compared to net volume of flow passing Kennedy, however, the peak flow at Kennedy is much greater than the peak flow at Broadway. The reason for this is the vast amount of overbank storage that is available between the wide setback levees that run through Gary.
In Gary, the design floodplain between the north levee and the south levee can be almost three quarters of a mile wide compared to only a couple hundred feet in the west. In Gary during a flood, the flow spreads out into the wide low lying floodplain and is not confined to the channel as it is to the west. As the flow from the channel escapes into these large areas of overbank storage, the flow in the channel is reduced.
Question: Do the Towns and Cities along the river have the construction drawings and design information for their portion of the project? Will ACE provide protection in the event of flooding before the levee is complete?
Answer: The Towns and Cities have been provided with the project design documents and construction drawings. The contractor is required to maintain the existing level of protection throughout construction prior to the completion of the new levees and floodwalls.
Question: What plain is in place for March or the spring of this year, when the ice on the river starts piling up at the bridges and other restrictions, and we have snow melt, saturated ground, high rains and flood conditions?
Answer: A Flood Warning Plan was developed by the Corps of Engineers, and provided to the Little Calumet River Basin Development Commission at the completion of the levee construction east of Cline Avenue. The Flood Warning Plan has also been provided to the communities along the river to implement as part of the Levee Operations and Maintenance Manuals that describes the routine and flood response requirements for the project. The Flood Warning Plan provides advanced flood warning based on precipitation and stage information. The flood warning plan was reviewed using observed data from recent flood events and found to provide advanced flood warning for all the flood events reviewed. All the factors listed above were included in at least one or more of the flood events.
Question: If none, why did we spend so much money on a project that does not meet its objective?
Answer: See answer to the previous question.
Question: Does the NOAA level gauge at Munster base flow on actual flow measurements or by calculation based on depth?
Answer: For the USGS Little Calumet River at Munster gage, the USGS uses both stage and flow measurements to determine flow at this gage. For stage forecast flows, the National Weather Service (NOAA site) uses a precipitation model to forecast flows at the gage site. For more information, please contact the USGS or the National Weather Service.
Question: Based on the current height ("reveal") of the sheet piles, why does it appear that Stage 8 will have more flood protection than Stage 7?
Answer: Based on a visual inspection, it is reasonably to assume that Stage 8 has or will have more flood protection than Stage 7. However, this is not the case. The contractors on Stages 8 and 7 had the option to build a Pre-Cast Sheet Pile Floodwall or a Cast-in-Place Concrete Floodwall. On Stage 8, the contractor decided to use the Precast option where the current top of the sheet pile will be the final elevation of the floodwall with precast concrete panels attached to the landside face of the sheet pile. On Stage 7, the contractor decided to use the Cast-in-Place option where the current top of the sheet pile will NOT be the actual top of the floodwall. Several feet of reinforced concrete will still be added above the top of the sheet pile to reach the final elevation of floodwall. During construction of Stages 7 and 8, the existing level of flood protection provided by the existing berms is being maintained by the contractors.
Question: Of "all the earthen levees" designed by ACE, not counting piled and concrete levees, built to EM 1110-2-1913 since 2000, when the manual was revised, how many earthen levee failures have there been? How many piled and concrete levees have failed?
Answer: We have inquired across the Corps of Engineers and to date, there have not been any reports of failures of levees or floodwalls designed in accordance with our current design criteria (EM 1110-2-1913, dated Apr 2000).