dupage river, illinois meeting dupage riv… · erin maloney, p.e. us army corps of engineers...

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BUILDING STRONG®and Taking Care of People!

“The views, opinions and findings contained in this report are those of the authors(s) and should not be construed as an official Department of the Army position, policy or decision, unless so designated by other official documentation.”

Flood Risk ManagementFeasibility Study

Public Meeting

16 August 2018

DUPAGE RIVER, ILLINOIS

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Opening Remarks

Colonel Aaron ReisingerU.S. Army Corps of EngineersCommander, Chicago District

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Welcome

Scott Killinger, P.E.Will County Chief Subdivision Engineer

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Presenter

Erin Maloney, P.E.US Army Corps of Engineers

Chicago District

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AGENDA

How the U.S. Army Corps got involved

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6 Next steps

How flood problem areas were identified and evaluated

What solutions were considered

What is being proposedWhat was studied

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Public comments

Questions (after presentation)

BUILDING STRONG®and Taking Care of People! 6

Study LocationWatershed Area: 378 mi2

West Branch DuPage River 128 mi2

East Branch DuPage River 81 mi2

Mainstem DuPage River 169 mi2

Main Waterways:West Branch DuPage River 32 miEast Branch DuPage River 24 miMainstem DuPage River 27 miLily Cache Creek 14 mi(tributary to mainstem)


Historic Flooding

West Branch at Winfield CreekApril 2013

DuPage Mainstem at I-55 and Black RdJuly 1996

DuPage Mainstem at River RoadSeptember 2008

1996 – Up to 17 inches of rainfall over 24 hrs. Extensive structure damages, flooding at major roadways including Interstate 55.

2008 – Up to 10 inches of rainfall over 51 hrs. FEMA Individual Assistance (IA) totals: $2,300,000 (DuPage), $1,100,000 (Will).

2010 – Up to 7 inches of rainfall over 24 hrs. Impacts primarily on East and West Branches. FEMA IA total: $5,100,000 (DuPage).

2013 – Up to 7 inches of rainfall in 24 hrs. Record stages at several watershed gages. FEMA IA totals: $14,800,000 (DuPage), $4,300,000 (Will).


Study Scope

Overbank Elevated Groundwater

Local Sewer Backup

Evaluate Major Sources of Flooding

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Why is the U.S. Army Corps of Engineers, Chicago District

involved?

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Authorized by Congress(Section 206, Flood Control Act of 1958)

“…surveys for flood control and allied purposes…Watersheds of the Illinois River, at and in the vicinity of Chicago, Illinois”

New Start funding received in 2015

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DuPage County Stormwater Management Committee

Will County Executive Office

Chicago District

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Non-Federal Sponsor

US Army Corps of Engineers

Project Partners


How flood problem areas were identified and evaluated

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Public & Agency ParticipationJuly 2015Feasibility study start

July 2018Public review and comment period starts

November 2015NEPA scoping meeting with public

September 2015Site visit with sponsors and municipalities

March 2017Analysis validation with sponsors and municipalities

November 2015Coordination meeting with Federal agencies


Identifying Problem Areas

34 Damage Areas identified

Grouped into 31 Damage Reaches based on proximity for plan formulation and economic evaluation

Site Visits Public InputReview

FEMA Flood Maps

Confirm with

Hydraulic Models


What was considered

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Structural• Levees / Floodwalls – protect overbank flood prone areas• Reservoirs – store floodwater• Diversions – route flows away from damage prone areas• Channel Modifications – alter bridges or widen channels• Groundwater Control Structures

Non-Structural• Raise/floodproof structures• Buyouts• Flood warning and preparedness

Measures Considered


Screening Steps – Storage Example

1. Review open spaces along waterways2. Check for site conflicts (environmental, infrastructure, planned land use)3. Perform hydraulic modeling to determine potential flood reduction by storage areas4. Estimate benefit of storage using economic models5. Estimate cost to construct storage area based on general site conditions and

required features6. Compare project benefits to project costs7. Retain storage areas which indicate a possibility of positive net benefits for further

evaluation

DuPage River, Illinois Flood Risk Management Feasibility Study 18


Identified Measures

FirstScreening

SecondScreening

Levees/ Floodwalls 40 31 4

New Storage or Modifications to Existing

Storage94 94 5

Bridge Modifications 51 33 1

Channel Improvements 1 1 0

Diversions 3 4 1

Dam Modifications 4 3 1

Below Grade Cut-Off Walls 2 2 1

Non-Structural Physical Measures

10 non-structural alternatives developed

Nature Based Features Consider for all recommended projects

Evaluation of Measures – Site Screening


Measures were evaluated and screened based on:• Technical Feasibility• Cost Effectiveness• Environmental Acceptability

Remaining measures were grouped into alternative plans

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Measures to Alternatives


Selecting Alternatives

Identify Problem

AreasEvaluate Solutions

Economically Justified

Tentatively Selected Plan

Maximize net benefits when selecting alternatives:• Improve life safety• Reduce economic damages


What is the tentatively selected plan?

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Tentatively Selected Plan1 Structural Alternative:

• Lisle Levee ElevationNon-Structural Alternatives:

Branch Structure Count

West Branch 12East Branch 16Mainstem 14

Total 42


Overview of Lisle Levee System

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East Branch DuPage River

Homes & Businesses

Anatomy of a Levee


Background: How Levees Fail


Existing Conditions: Lisle Levee


• Remove vegetation and encroachments on and within 15 feet of the levee

• Increase height of levee to provide additional protection

• Flatten side slopes

• Install erosion control features

Lisle Levee Plan Components


Nonstructural Recommendation

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Nonstructural Measures

Elevation Buyout or Relocation

(mandatory)

Dry FloodProofing

Wet FloodProofing


Selection Criteria


Example of Elevating a Home

Before

After


Nonstructural Alternative

Branch Structure Count

West Branch 12East Branch 16

Mainstem 14Total 42

Additional structures may be added on the tributaries upon final economic analysis


What to Expect as a Property Owner

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Input from notified individuals regarding measure selection incorporated

Late 2018 - Notice provided to eligible property owners

Final economic cost benefit analysis complete to confirm final recommended plan

From now through completion of this study (July 2019):


What to Expect as a Property Owner

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Initial meeting to discuss next steps and benefits

Notice given to affected property owners (and any tenants)

Process implemented with input from owners

If the project is authorized and funded by Congress:


Presenter

Imad SamaraUS Army Corps of Engineers

Chicago District

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Public Review Period Now – August 30, 2018

Feasibility Report Approval July 2019

Congressional Authorization *TBD

Congressional Appropriation *TBD

Design/Construction *TBD

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Next Steps


We want your feedback

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How to Find the Report

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https://www.lrc.usace.army.mil/Missions/Civil-Works-Projects/DuPage-River/

Or internet search for: “Army Corps DuPage River Watershed”


In-Person

E-mail: [email protected]

Mail: USACE, Chicago District231 S. LaSalle St, Ste. 1500Chicago, IL 60604ATTN: Planning Branch (DuPage River)

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or

Must be sent or postmarked by:September 22, 2018

How to Comment


Questions

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https://www.lrc.usace.army.mil/Missions/Civil-Works-Projects/DuPage-River/

dupage river, illinois meeting dupage riv… · erin maloney, p.e. us army corps of engineers...

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