Fargo-Moorhead Metropolitan Feasibility Study

Fargo-Moorhead

Metropolitan Feasibility

Study

Presentation

for

City Engineers

Association of

Minnesota

January 28, 2010

28 January 2010 2

Partners

Corps of Engineers

City of Fargo

City of Moorhead

Metropolitan Flood Management Committee

28 January 2010 3

Why We Are Here

Fargo-Moorhead area

has significant flood

risk

Provide an overview

of the process and

outcomes of the

Fargo-Moorhead

Feasibility Study.

Fargo-Moorhead Flood 2009

28 January 2010 4

Funding and Costs

Study costs are shared 50% federal, 50% non-federal

Congress provides federal funds to the Corps

Non-federal funding is provided by:

City of Fargo, ND

City of Moorhead, MN

Buffalo-Red River Watershed District, MN

Cass County, ND

Estimated study cost: $8,000,000

Construction costs are shared 65% fed, 35% non-fed

28 January 2010 5

Planning Process

1. Specify problems and opportunities.

2. Inventory and forecast conditions.

3. Formulate alternative plans.

4. Evaluate effects of alternative plans.

5. Compare alternative plans.

6. Select recommended plan.

28 January 2010 6

Study Goals

Develop a system to reduce regional flood risk

Determine the Federal role in implementation

Document findings in a Feasibility Report

Recommend a project to Congress

28 January 2010 7

Study Area

Fargo-Moorhead

metropolitan & surrounding

area

North: Harwood, ND &

Kragnes, MN

South: Oxbow, ND

East: Dilworth, MN

West: West Fargo, ND

28 January 2010 8

Risk

The 2009 flood was

approximately a 125 year flood

event.

Successful flood fights lead to a

false sense of security.

It would be very difficult to fight

floods larger than the 2009 flood.

Failure of emergency levees

would be catastrophic.

Building of 2nd St. Levee for 2009 Fargo-Moorhead Flood

28 January 2010 9Potential Depths of Inundation

28 January 2010 10Potential Depths of Inundation

28 January 2010 11

Loss of Life

Event

Anticipated

Event

98%

Evacuation

Unanticipated

Event

0%

Evacuation

1% Chance

(100 yr)4 200

0.2% Chance

(500yr)12 594

*Assume Total Metro Population 202,684

28 January 2010 12

Hydrologic record shows two periods: wet and dry

Annual Peak StagesU.S.G.S Station - 05054000

0

5

10

15

20

25

30

35

40

45

50

1882 1905 1910 1915 1920 1925 1930 1935 1940 1945 1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005

DATE

ST

AG

E, fe

et

FEMA 500-yr Event FEMA 100-yr Event FEMA 50-yr Event FEMA 10-yr Event

FEMA 100-yr Event

Wetter Climate?

28 January 2010 13

Wetter Climate?

Panel of experts met to discuss hydrology Confirmed increasing trend in flood flow and frequency

Cause of increasing trend is not known

Red River has wet & dry cycles

Currently in a wet cycle, but will eventually switch to dry cycle

Recommendations Use non-standard hydrologic method to estimate future flows

Assume that continued wet conditions are more likely than dry

Actions taken Corps developed modified flow/frequency curves

Will use modified curves for sensitivity analysis of selected plan

28 January 2010 14

Alternatives

No Action: Continue Emergency Measures

Nonstructural measures Buyouts, Relocations, and Elevate

Increase conveyance Diversion Channels

Flood barriers Levees/Floodwalls

Flood storage Large/Small

28 January 2010 15

Initial Screening Criteria

Effectiveness: Ability to provide acceptable level of flood risk management

Environmental Effects: Effects on natural and cultural resources

Social Effects: Effects on socio-economic resources

Acceptability: Controversy and potential effects on community

Implementability: Technical, social, legal or institutional issues

Cost: The first cost of the project and operations and maintenance.

Risk: The uncertainties surrounding the project

Separable Mitigation: Is separable mitigation required and what is the cost

Cost Effectiveness: Comparison of benefits and costs

28 January 2010 16

Preliminary Screening ResultsScreened Alternatives Ranked by Net Benefits

Alternative First Cost *

Avg Annual

Net Benefits *

Residual

Damages * B/C Ratio

MN Short Diversion 25K 962 11.0 14.3 1.22

MN Short Diversion 35K 1,092 9.4 9.3 1.17

Levee 1% chance (100-year) 902 7.7 20.9 1.17

MN Long Diversion 25K 1,055 5.6 15.0 1.10

MN Short Diversion 45K 1,264 2.5 7.4 1.04

MN Long Diversion 35K 1,260 0.3 9.8 1.00

ND East Diversion 35K 1,337 -3.1 9.2 0.95

ND West Diversion 35K 1,363 -4.4 9.2 0.94

Levee 2% chance (50-year) 840 -5.3 37.1 0.88

ND West Diversion 45K 1,439 -6.7 7.6 0.91

MN Long Diversion 45K 1,459 -8.3 8.2 0.89

* In millions of dollars

Note: Expected average annual damages without a project are $73.7 million.

28 January 2010 17

Final Screening Alternatives

Diversion Channels with Tie Back Levees Minnesota

North Dakota

28 January 2010 18

Detailed Analysis

Working on Detailed Analysis

MN Diversions with Tie Back Levee

4 separate plans (4 capacities: 20,000,

25,000, 30,000, and 35,000cfs)

ND Diversion with Tie Back Levee

1 plan (2 capacities: 30,000 and

35,000cfs)

28 January 2010 19

Preliminary ResultsEffects of Diversions

STAGE at the FARGO GAGE

2% Chance 1% Chance 0.2% Chance

(50-year) (100-year) (500-year)

Existing Condition 37.8 39.5 43.9

25k Diversion 29.1 30.4 39.2

35k Diversion 28.8 29.2 35.9

45k Diversion 27.1 27.2 30.4

Stage Impacts

27 Fargo Elm Street closed

30 Fargo 2nd Street Dike installed

31 Moorhead 1st Ave. North closed

32 First homes in Moorhead threatened

35 First homes in Fargo threatened

40.8 2009 Flood Record Stage

28 January 2010 20

Preliminary ResultsEffects of Diversions

15.0

20.0

25.0

30.0

35.0

40.0

45.0

50.0

2% Chance (50-year) 1% Chance (100-year) 0.2% Chance (500-year)

Sta

ge

in

Fe

et

Existing Condition 25k Diversion 35k Diversion 45k Diversion

28 January 2010 21

Recreation

Eligible Recreational Facilities Trails – Hiking, Snowmobile, Cross Country Skiing, etc.

Footbridges

Fishing Facilities

Picnic Shelters, Overlooks, Restrooms

Camping facilities, picnic tables, grills, etc.

Multiple Use Courts

Interpretative Signs and Information

28 January 2010 22

Path Forward

Uncertainties: Natural Resource impacts (fish passage – greater for ND diversion

alignments)

Additional project benefits

Impacts to upstream/downstream landowners

Upcoming Tasks Develop additional benefit information

Develop costs for any negative impacts

Narrow down capacity alternatives

Choose 1 alignment

28 January 2010 23

Local Decisions

What level of risk is tolerable?

36 feet for a 500-year event.

What locally preferred options need to be retained?

MN 35K, ND 30 & 35K

Identify sponsors for construction and ongoing O&M

Define non-federal cost sharing arrangements

Non-federal share of the NED plan will be 35-50% of costs

All costs in excess of the NED plan are 100% non-federal

Develop local consensus

28 January 2010 24

F-M METRO STUDY TIMELINE

Feb 2010: Identify unofficial tentatively selected plan

Feb 2010: Public Meeting

Mar 2010: Independent External Peer Review

Apr 2010: Corps headquarters approval to release draft

May 2010: Formal Public Review of Feasibility

Report

Sep 2010: Finalize feasibility report

Dec 2010: Transmit recommendation to Congress

Jan 2011: Begin Plans and Specifications

Apr 2012: Begin Construction

28 January 2010 25

Red River Basin Wide Feasibility

28 January 2010 26

Red River Basin Wide Feasibility

Sponsors MN Red River Watershed

Management Board

ND Red River Joint Water Resource District

Cost Share 50/50

All local share as WIK

Acceptable WIK Coordinated in advance

Provides information beneficial to the Basin

Project Overview

28 January 2010 27

Red River Basin Wide Feasibility

Phase I – LiDAR Collection – complete

Processing – ongoing

Development of web viewer

Used in 2009 flood

Phase II - Modeling HEC-RAS for entire Red River

HEC-HMS for watersheds

Mike-11

Phase III - Decision Support System Development of tools for local use

Modification of RRBDIN (IWI)

Needs Local Direction

Final Report Basin Goals and Objectives (RRBC)

Existing and future conditions

Information on tools developed in study

Project Overview

28 January 2010 28

Red River Basin Wide Feasibility

H&H Modeling

Mike 11 - RRBC

HEC-RAS – Corps

Extending Cross sections

Working with NWS on forecasting

HEC-HMS - Corps

Decision Support System

GIS analysis of LiDAR

Identify storage opportunities

Identify restoration opportunities

Public Outreach and Collaboration (RRBC/IWI)

Flood Forecast Tool

Drought Forecast Tool

Long Term Maintenance, Support, and Upgrades

Future/Ongoing Work

28 January 2010 29

Red River Basin Wide Feasibility

Develop Tools and Information Addressing the Needs of the individual Stakeholders

Cities

Counties

States

Watershed Districts

No Federal Implementation

Sponsors Role Continue to identify needs in the basin

Provide financial and political support

Continue participation in the study

Encourage Public participation in the future.

Direct future planning efforts

Purpose of Corps Involvement

28 January 2010 30

Questions?

Information on back of handout

Please sign our sheet to get future mailings.

Website: http://www.internationalwaterinstitute.org/feasibility

Email:

Craig Evans – [email protected]

Aaron Snyder – [email protected]

Mail:

USACE, St. Paul District

190 5th St. E.

Suite 401

St. Paul, MN 55104