Minutes - 2007 - City Council - 03/20/2007 - Regular
v
EAGLE CITY COUNCIL
Minutes
March 20, 2007
PRE-COUNCIL AGENDA: 6:30 p.m. - 7:30 p.m.
A. Report bv Mavor's Youth Advisory Members:
Mayor introduces the issue.
Ben Hayden, Mayor's Youth Advisory Committee: I went to the National Leagues of Cities
Conference in Washington DC with Theresa and the Mayor. Discusses meeting with Mike
Crapo and presentation of information on the March Against Meth. Discussion on the
workshops attended. General discussion. Video on the March Against Meth played.
Discussion on the March Against Meth.
B. Ada County Hil!hwav Districts Ril!ht-of-Wav Task Force will present the proposed
chanl!es to ACHD'S work in the ril!ht-of-wav policv. Presenter: Bryan Huey
Mayor introduces the issue.
Angela Coomish, Civil Engineer, Engineering with a Mission, I work with ACHD. About three
years ago I gave a presentation as curser to this report. I have gathered information from cities
and entities. We have come up with a proposed ordinance for contractor's who are working in
the right-of-way. We had a task force that worked on this ordinance. Provides an overview of
the Right-of-Way Policy ordinance proposed by ACHD. General discussion.
C. Carter Borden with Dill Water and Environment will present information rel!ardinl!
flood modelinl! proposals.
Mayor introduces the issue.
Carter Borden provides Council with an overview of how the Boise River is operating in the
region. Discussion on joint venture with the IDWR and the University of Idaho. Discussion on
Eagle Island State Park. Discussion on the modeling software and funding. General discussion.
Mayor calls a recess at 7:35 p.m.
REGULAR COUNCIL AGENDA: 7:30 p.m.
I. CALL TO ORDER: Mayor calls the meeting to order at 7:45 p.m.
2. ROLL CALL: BASTIAN, GUERBER, NORDSTROM, BANDY. All present. A quorum is
present.
3. PLEDGE OF ALLEGIANCE
4. PUBLIC COMMENT: Jason Gibson, 2217 W. Burn Street, I would like to talk on some
issues I have seen around the City of Eagle. I would like to start by quoting Milton Fredman,
reads a quote. Mr. Gibson did not want to comment on any specific issues.
Teri Bath, President of Chamber of Commerce, discusses the Feasibility Committee and the
Urban Renewal Board. We had two companies give us a bid on information and drawings for the
downtown core. The Committee voted to award the bid to Visual Genesis, Project III, in the
amount of $17,000.00. We would like to get Council's decision as soon as possible. We also
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some expenses for Urban Renewal that could be taken out of the Feasibility Budget. General
discussion.
Council concurs to place the bids on the next city council agenda.
5. CONSENT AGENDA:
· Consent Agenda items are considered to be routine and are acted on with one
motion. There will be no separate discussion on these items unless the Mayor, a
Councilmember, member of City Staff, or a citizen requests an item to be removed
from the Consent Agenda for discussion. Items removed from the Consent Agenda
will be placed on the Regular Agenda in a sequence determined by the City Council.
. Any item on the Consent Agenda which contains written Conditions of Approval
from the City of Eagle City Staff, Planning & Zoning Commission, or Design
Review Board shall be adopted as part of the City Council's Consent Agenda
approval motion unless specifically stated otherwise.
A. Liquor, Beer & Wine License: Retail Development of North America LLC
dba: Six One Six is requesting the above mentioned license to be utilized at 1065
E. Winding Creek Dr. Ste. 100. Note: This is a transfer of a/coho/license
ownership. (SKB)
B. Minutes of March 13,2007.
City Clerk: I would like to remove Item #3A from the Consent Agenda, this license can be
approved contingent upon payment of the fees.
Bastian moves to approve the Consent Agenda minus Item #A. Seconded by Guerber.
ALL AYES: MOTION CARRIES....................
General discussion on the fees for the transfer of licenses.
Bastian moves to approve the beer and wine license for Ronald W. Bath and Teresa A.
Bath conditioned upon receipt of fees for the license. Discussion. Bastian: AYE; Guerber:
AYE; Nordstrom: AYE; Bandy: AYE: ALL AYES: MOTION CARRIES....................
6. PUBLIC HEARINGS: None
Guerber moves to hear Item #7C next. Seconded by Nordstrom. ALL AYES: MOTION
CARRIES...............
7. UNFINISHED BUSINESS:
C. Presentation of the Eal!le Center for the Arts Feasibilitv Studv: Bill Stephan and Linda
Butler
Mayor introduces the issue.
Bill Stephan, Eagle Arts Commission, provides the Council an overview of the Arts Feasibility
Study. The one thing that we are really missing is a public arts venue for performing arts.
The citizens of eagle favor the creation of a public arts venue and favor public and private
funding. We have a potential site near the Camille Beckman facility. The study has created a
vision of what the facility can provide. General discussion.
Linda Butler: We need to know where we go from here. We need to move forward and we need
the Councils' input. We need to secure a site, a design needs to be done, the funding element
possibly looking at private/public funding including a bond election. We need to establish a task
force to take us forward. General discussion on forming a task force. Council concurs to have
the Arts Commission move forward to form a task force.
Bill Stephan: We also would like to request that the Council approve the plan. Council concurs
to add this item to the Agenda for next week.
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Further general discussion.
A. Discussion of Rib Shack: This item was continuedfrom the March 13, 2007 meeting. (SEB)
Mayor introduces the issue.
City Attorney Buxton: I thought we had an agreement with Mr. Charney on February 22, 2007
and Mr. Charney has proposed a counteroffer where Andrew would not be on the agreement.
General discussion.
Bastian moves to approve the Mutual Release and Settlement Agreement and remove all of the
red letter words. Seconded by Guerber. Discussion. TWO A YES: TWO NAYS: Mayor: NA Y:
MOTION FAILS.
Bandy moves to modify agreement to remove Section 2D only and leave all other text as
written. Seconded by Guerber. THREE AYES: ONE NAY: MOTION CARRIES.........
B. Discussion of AATronics Bid: This item was continuedfrom the March /3,2007 meeting.
(ME)
Mayor introduces the issue.
Mike Echeita: We continued this item from last weeks meeting because the Mayor was absent
from the meeting. The proposal for the sound in the lobby would be $2,216.97. The price to do
the whole system in the lobby and the conference rooms is $5,978.64. General discussion.
Nordstrom moves to extend sound into the lobby. Seconded by Bastian. Bastian: AYE;
Guerber: AYE; Nordstrom: AYE; Bandy: AYE: ALL AYES: MOTION
CARRIES...............
8. NEW BUSINESS:
Bastian moves to amend the Agenda to add as Item #8B. Valley Regional Transit letter.
Seconded by Bandy. ALL AYES: MOTION CARRIES...............
A. Blue Print for Good Growth APF - Discussion and Action: (NM)
Mayor introduces the issue.
Planner Baird Spencer: Provides Council an overview of the Blue Print for Good Growth. You
opted not to continue funding. Discussion on how development will pay for itself and the
development of an ordinance. The Blue Print for Good Growth is now proposing their
ordinance. I do not believe that we all need to be part of a single ordinance. Discussion on the
slide show from Blue Print for Good Growth. General discussion.
Nordstrom moves to have staff address The Blue Print for Good Growth with a thank you
and the fact that we are going to take on the responsibility of facilities planning on our
own. Seconded by Bastian. ALL AYES: MOTION CARRIES...............
Further discussion.
B. Valley Regional Transit - Support for Grant Funds for Federal Funds.
Mayor introduces the issue.
Bastian moves to approve the letter of support from the Mayor of the City of Eagle and
authorize her to sign to help Valley Regional Transit in their effort to request funding from
the Federal Highway Administration Transportation Board. Seconded by Nordstrom.
Discussion. ALL AYES: MOTION CARRIES...........
Mayor calls a recess at 9: 15 p.m.
Mayor reconvenes at 9:25 p.m.
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9. WORK SESSION:
10. EXECUTIVE SESSION:
A. Personnel Matters: I.C. S67-2345 (b)
B. Pending & Threatened litigation. I.C. S67-2345 (f)
Mayor introduces the issue.
Nordstrom moves to go into Executive Session for the discussion of Personnel Matters: I.C.
~67-2345 (b) and Pending & Threatened litigation. I.C. ~67-2345 (I). Seconded by Bastian.
Bastian: AYE; Guerber: AYE; Nordstrom: AYE; Bandy: AYE: ALL AYES: MOTION
CARRIES..............
Council goes into Executive Session at 9:25 p.m.
Council discusses personnel matters and pending and threatened litigation.
Council leaves Executive Session at 10:20 p.m.
II. REPORTS:
City Engineer Report: No report
City Clerk/Treasurer Report: Tracy, Sheri, and I will be at the Mountain West Clerk's Institute
Wednesday through Friday
Mayor and Council's Report:
Nordstrom: No report
Guerber: No report
Bandy: Reports on the Economic Development meeting last Thursday.
Bastian: The Legislature approve the $3M funding for the bridge at Eagle Island State Park
Mayor: Distributes information to the Council and discusses her calendar.
Discussion on the Merrill Park Bridge.
Discussion on the Boise River Action review.
Discussion on Mayor's March 2151 meeting. Mayor gives a report on her conversations with
Chuck Carlise in regards to the access to the byway. He also has 2,000 acres of property by
Hidden Springs and he wanted to know if the City had any interest in annexing his property into
the City. General discussion.
You will see a refund to Lori Campbell on her Merrill Park reservation for her wedding and an
offer to her for Guerber Park. Lori has a reservation for her wedding at Merrill Park at the same
time as the Healing Field. Sheri didn't know that we needed the shelter for the Healing Field.
She will need to change the time of her wedding. She is still reserving the Gazebo and the
she Iter.
We need to schedule a ribbon cutting ceremony for Guerber Park.
Dave Milan: they plan on being done and ready for a walk through at Guerber Park the end of
the month.
I have met with Dave, Nichole, Bill and Ted today on the transportation task force. General
discussion.
Dave Milan: Discussion on Hill Road alignment meeting. They are going to base their decision
on public comment. General discussion.
Mayor provides a report on the Healing Fields event. We have a binder on the organization of
the event. There are several committees that need to be formed. We have a youth working on
each of these areas but we need to get adult support. When I hired Theresa there was a gal that
was a Veteran's coordinator and I would like to talk to her about coordinating this event. I need
to hire a program coordinator which could cost $5,000.00. General discussion.
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Nordstrom moves to have the Mayor hire a project coordinator for the Healing Fields
project for no more than $5,000.00. Seconded by Bandy. ALL AYES: MOTION
<:ARRIE~..........
Mayor: Discussion on the Budget workshop she took at National League of City. It involves
getting the citizens involved in the budget project as to what they want and you base your budget
on these recommendations. This is called Budgeting for Outcomes. General discussion on
budgeting. Council would like to have a mid-year review.
City Clerk Bergmann: Mayor I need to get a roll call on Scott's motion for the project
coordinator for the Healing Fields. Bastian: AYE; Guerber: AYE; Nordstrom: AYE; Bandy:
AYE: ALL AYES: MOTION CARRIES..................
Zoning Administrator's Report: Discussion on the Development Agreement with Laguna Pointe
in regards to the club house and the office complex proposed. We have a request from an Art
Gallery to locate in this development. I think that this request should be brought to the Council.
General discussion.
Discussion on the Lighthouse Subdivision and the installation of dry lines and that they were not
going to be connecting to central water. United Water has sent over a letter stating that they do
not accept dry lines.
City Attorney Report: No report
Public Works Director Report:
12. ADJOURNMENT:
Guerber moves to adjourn. Seconded by Bastian. ALL AYE: MOTION
CARRIE~...
Hearing no further business, the Council meeting adjourned at II: 15 p.m.
Respectfully submitted:
Ji0-k.. L(6o~
- SHARON K. BERGMANN
CITY CLERK/TREASURER
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A TRANSCRIBABLE RECORD OF THIS MEETING IS AVAILABLE AT EAGLE
CITY HALL
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Mayor: Nancy C. Merrill
March 20, 2007
Kelli Fairless, Executive Director
Valley Regional Transit
830 N. Main Street, Suite 230
Meridian, Idaho 83642
Dear Ms. Fairless,
CITY OF EAGLE
P.O. Box 1520
Eagle, Idaho 83616
939-6813
Council: Stanley J. Bastian
Phil Bandy
Steve Guerber
Scott Nordstrom
The City of Eagle understands that Valley Regional Transit is seeking grant funds from
the Federal Highway Administration's "Transportation, Community, System
Preservation" (TCSP) program, to support a traffic analysis and to purchase capital
materials to implement a regional bus stop system that links eight cities with dedicated
transit stops that currently do not exist.
We believe this project is needed to move forward with alternative transportation options
within and outside of our local jurisdiction, and further supports the connectivity of
public transportation that would result throughout the region.
We appreciate Valley Regional Transit's efforts on providing high quality transportation
service to the community and support your application for federal funding.
We further commend Valley Regional Transit for moving forward with transportation
projects that meet local and regional transportation goals.
Sincerely,
1 /L:s/
•Fancy C. Merrill
Mayor
cc: Eagle City Council
(
MEMORANDUM
TO: Accounting/City Clerk's Department
RE: Reimbursement of Park Reservation Fees to Holly Campbell
DATE: March 9, 2007
•
Due to the Healing Fields flag event at Merrill Park on May 19, I spoke with
Lori Campbell regarding her daughter's reservation to use the picnic shelter that
afternoon for her wedding, and I offered her to relocate to the new Guerber Park
location instead. She, however, would like to keep her reservation at Merrill
Park. She understands the park will be full of people for the Healing Fields
event and parking may be a problem, so I have offered to reimburse Holly's park
fees due to any inconvenience it may cause on that day. In addition, I have
offered her another park reservation at no charge another time.
ce
Please provide reimbursement in the amount of o Holly ampbell and
allow for another one-time use at no charge. Thank you.
APPROVED -
AMOUNT PMD:
ACCOUNT#:
CHECK #:...r...��
DATF•
p-0
MUTUAL RELEASE AND SETTLEMENT AGREEMENT
THIS MUTUAL RELEASE AND SETTLEMENT AGREEMENT ("Agreement") is
entered into by and among the City of Eagle, Idaho, an Idaho municipal corporation ("City"),
and Eagle Rib Shack, LLC (—eotiircly "Rib Shack"), and is intended to
effect the extinguishment of obligations herein. The City and Rib Shack are collectively referred
to as the "Parties."
In mutual consideration of the covenants contained herein, the City and Rib Shack agree
as follows:
1. RELEASE
Disputes and differences have arisen between the City and Rib Shack with respect to the
tent erected over the outdoor patio on the Rib Shack's leased premises located at 360 East State
Street, Eagle, Idaho, 83616. Those disputes are reflected, at least in part by letters, emails and
the Appeal (#AA -01-07) to the Eagle City Council heard on February 20, 2007. By this
Agreement, the Parties, for themselves, their successors, heirs, assigns, servants, agents,
employees and representatives, together with any and all persons acting for, by or through them,
or any one of them, individually, collectively and severally release each other from all claims,
liabilities, demands, contracts, and/or agreements, costs, expenses, promises, damages,
representations, actions and causes of action, and judgments of every kind, in any manner
whatsoever resulting from or arising out of the above described tent erected on the Rib Shack
premises as set forth in this Agreement.
2. CONSIDERATION
A. Rib Shack agrees to remove the tent from 360 E. State Street, Eagle, Idaho on or
before Tuesday, April 24, 2007, and Rib Shack further agrees not to erect any tent in the future
without first obtaining a permit from the City of Eagle and permission for such permit
application(s) to be filed from the landowner of any property owner which such tent would be
erected.
B. Rib Shack agrees to waive any and all claims they may have or had with respect
to the tent, or the appeal taken to the City Council on February 20, 2007, designated #AA -01-07,
which appeal was denied by City Council on that same date. Rib Shack also waives any
requirement that the City draft a written decision denying Administrative Appeal #AA -01-07.
C. The City agrees to take no adverse action against Rib Shack prior to Tuesday,
April 24, 20007. If the tent is not removed on or before April 24, 2007, the City may take
whatever action, civil, criminal or both, to remove the tent, after said date.
MUTUAL RELEASE AND SETTLEMENT AGREEMENT - 1
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I. The City agrees to process applications submitted by Rib Shack for a permit(s) at
another location as required by Eagle City Code and other applicable laws and policies. in a
timely fashion.
3. NO ADMISSION OF LIABILITY OR CULPABILITY
It is understood and agreed that this settlement is a compromise of doubtful and disputed
claims. and that the consideration set forth herein is not to be construed as an admission of
liability or culpability on the part of the Parties hereby released and that each Party expressly
denies liability, and intends merely to avoid litigation and to buy its respective place.
4. DISPUTE RESOLUTION
If a dispute between the Parties arises out of or relates to this Agreement or breach
thereof, and if the dispute cannot be settled through negotiation, the Parties agree first to attempt
in good faith to settle the dispute by mediation before resorting to litigation. The Parties agree to
share equally in the mediator's fees and expenses.
5. JURISDICTION AND VENUE
This Agreement shall be construed in accordance with the laws of the state of Idaho in
effect at the time of the execution of this Agreement. Any action brought in connection with this
Agreement shall be brought in the Fourth Judicial District of the State of Idaho.
6. REPRESENTATION OF COUNSEL
Both Eagle and Rib Shack acknowledge they each have been represented by legal
counsel in negotiating this Agreement and that neither party shall have been deemed to have
been the drafter of this Agreement.
7. ATTORNEYS' FEES
In the event a Party must take an action to enforce its rights under this Agreement, the
prevailing party in any resulting litigation shall be entitled to recover reasonable costs and
attorneys' fees incurred in connection herewith.
MUTUAL RELEASE AND SETTLEMENT AGREEMENT - 2
8. BINDING EFFECT
This Agreement shall be binding upon and inure for the benefit of the heirs, successors,
agents, employees and assigns of the Parties.
IN WITNESS WHEREOF, the undersigned have executed this Agreement as of the
date first written below.
Eagle Rib Shack, LLC City of Eagle Idaho
By:
Andrew Petrehn,
Lb I "' as President
of Eagle Rib Shack, LLC
Approved as to Form:
Dennis M. Charney
Attorney for Eagle Rib Shack, LLC
And Andrew Petrehn
1/
11
11
11
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By:
Nancy C. Merrill
Mayor
ATTEST:
Sharon K. Bergmann
City Clerk
Approved as to Form:
Susan E. Buxton
City Attorney
City of Eagle
MUTUAL RELEASE AND SETTLEMENT AGREEMENT - 3
STATE OF IDAHO
)ss.
County of Ada
On this day of , 2007 before me, Andrew Petrehan, i i
President of Eagle Rib Shack, LLC. known or identified to me, to be the person
whose name is subscribed to the within instrument, and acknowledged to me that he/she
executed the same.
SUBSCRIBED AND SWORN to before nye this day of , 2007
setwAt,-of-At
)ss.
Notary Public for Idaho
Residing at
Commission Expires
t p'-Sf . 2007`bt'f-. - -&rYru.e€1.i .tralaaa._41 i
r i . . 1 . ' . 1
nsiterrt-af-Eagle-Rib-S1t ,
to me, to be
the p5ei'StriViTae name is surged"CS"Clt [tiTIi1111 711711 i' kiY fig l o me t la die
ettTtrd ie same.
— SSTERIBBD =AN'D SWeRN-to-be#vre-me-this -rtap-of- ,2013T -
Notar is for Idaho
-F�sid.i.ng�t
MUTUAL RELEASE AND SETTLEMENT AGREEMENT - 4
STATE OF IDAHO )
)ss.
County of Ada )
On this day of , 2007 before me appeared Nancy C. Merrill, in her
capacity as Mayor for the City of Eagle, Idaho, known or identified to me, to be the person
whose name is subscribed to the within instrument, and acknowledged to me that she executed
the same.
SUBSCRIBED AND SWORN to before me this day of , 2007
Notary Public for Idaho
Residing at
Commission Expires
MUTUAL RELEASE AND SETTLEMENT AGREEMENT - 5
3/20/2007
Eagle
Chamber of Commerce
Eagle City Council
660 E Civic Lane
Eagle, ID 83616
Eagle City Council,
Cc 3--„2 0 -07
Jhe City with; more
ri y4t outiicle (Jour door.
Please find the following documents for the Downtown Feasibility Committee and Urban
Renewal.
The Chamber is requesting reimbursement for expenses on the following documents.
(See attached)
You will find in the packet two bids for the drawings, aerials and view corridors of the
downtown. The Feasibility Committee already voted to go with Visual Genesis. They
produced the more informational product.
The Feasibility Committee also would like to request a petty cash fund for copies and
mailers. We are getting ready to do a mailer which will go out to approximately 350
people.
On another note, the Eagle Chamber of Commerce would like to request more space in
the facility we are currently occupying if the museum should ever decide to move to
another location.
If you have any questions please feel free to contact:
Teri Bath Jason Pierce
67 E State Street PO Box 864
Eagle, ID 83616 Eagle, ID 83626
208-939-4222 208-938-5522
I want to sincerely thank the council for the opportunity to serve and be a part of this
exciting time in Eagle Idaho.
Sincerely,
L./4 -c/ '2-'2/
Teri Bath
Eagle Chamber of Commerce
P.O. Box 1300 • 67 E. State Street 208.939.4222 www.eaglechambercom
Eagle, Idaho 83616 fax 208 939 4234 eaglechamber@eaglechamber.com
//_
• "'
Eagle City Downtown
Flyover Proposal
LAND DEVELOPMENT MARKETING AND DESIGN
2-15-07
I would like to thank Terry Bath at the Eagle Chamber of Commerce, The Eagle
Economic Development Committee and the City of Eagle for the opportunity to bid on
the proposed City of Eagle Downtown Flyover Multi -Media Video. We have provided a
detail of the quote listing the services we are able to offer to complete the project as
specified. We are confident we will provide you with a superior quality finished product
to assist you in marketing the city of Eagle. We look forward in anticipation of working
with you on this project, as well as assisting in the growth of Eagle.
Sincerely,
Jard Barr
President,
The Terra Firm, Inc.
Ro `ert D- fayette
Vic Pre dent of Sales
The ' -rra Firm, Inc.
LAND DEVELOPMENT MARKETING AND DESIGN
Project: Eagle City Downtown Flyover Video Presentation
Project Scope: Create a video flyover of the downtown area covering the following areas geographically:
4 blocks in all directions from the downtown 4 Corners of Eagle and Old State Street. Below is the list of scope
details covering the entire feature by feature. We have provided an attached map overview of the actual
coverage of the video flyover, the path of the flyover and the areas that will be modeled and shown in the video.
(Please see the attached map overview of the flyover stream.)
Street Level Detail Scope: We will model out all buildings, sidewalks, light fixtures, trees, bushes, parks,
street signs, and provide pedestrians and vehicles if desired.
Building Level Detail Scope: We will model out all windows, doors, building fascia, and other detail of all
buildings in the modeled flyover area. We will also apply all exterior building textures to each building
creating the exterior look desired and based off of present and future building renderings.
Shadow Level Detail Scope: We will render out the entire project with all shadows at a 2:00 afternoon sun,
mid June. (We have chosen this because the trees will be fully developed with all leaves, flowers will be in
bloom. (Note: I f a different time of day or month is desired we can accommodate this as well.)
Music and Voice -Over: We will provide background music and voice-over as needed to point out new
proposed developments if desired.
Detail Level Scope: All buildings, trees, shrubs, streets, light fixtures, signs, etc. will be produced with a Semi -
realistic, High resolution texture and material level of detail.
*We will provide the video on a DVD format that will run on all DVD players, projectors, computers, etc.
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Project: Eagle City Downtown Flyover Video Presentation
Project Quote Pricing:
Entire Project will include the following Services needed
Street Level Detail Scope
Building Level Detail Scope
Shadow Level Detail Scope
Detail Level Scope
Music and Voice -Over
All Work will be provided on a final DVD as well as electronic files to be used at the
discretion of the City of Eagle.
Project Cost: $13,000.00
Cc 3--a -o7
Blueprint for Good Growth
Adequate Public Facilities
Implementation
CapacityDemand
C pital Plan
Unintended consequence slides
adapted from presentation by
Rich Unger, AICP
What is APF?
➢ A requirement that:
>specified public facilities and services
>in defined areas
➢are available
>at the adopted level of service (LOS)
standard
>at the time that the impacts of development
will be felt
>so that adopted levels of service are
maintained
1
Specified Public Facilities
➢ Transportation
➢ Water
9 Sewer
➢ Schools
➢ Stormwater Management
➢ Fire Protection
Transportation APF
Implementation Considerations
➢ Areas of applicability
➢ Public facilities included
➢ LOS standards
➢ Current & projected capacities
➢ Types of applicable development
➢ Timing of determination
➢ Effect of failure to meet LOS
➢ Allocating/monitoring capacity
2
3
LOS Stancar45
> Measured based on volume/capacity
> Jointly developed by local governments and
ACHD through TLIP
➢ LOS standards should
>Consider constrained facilities
Identify areas that allow more conge
tisi>Consider travel mode options
>Allow less congestion outside of urban
areas
4—Ordinance must
consider timing
of facility
completion
4
Applicable Development
> New subdivisions
> Non-residential site plans
➢ Multi -family site plans
> Exempt (de minimis) development must be
tracked
Measuring Demand
• Proposed — traffic from
proposed development
Approved — approved, but
unbuilt + demand from
exempt development +
projected background
traffic
Existing — existing internal
& external traffic
Approved
5
10 Effect of Failure to Meet LOS_
Timing of Determination,
Assignment & Mitigation
> Early determination provides more
predictability for all
> Early determination requires accurate
tracking of approved, but un -built demand
> Early assignment benefits private interests
> Early assignment of capacity complicates
monitoring and requires expirations
• Mitigation must be coordinated with demand
creation
➢Disapproval
> Disapproval
> Demand Reduction
> Demand Phasing
> Capacity Enhancement
6
Aiiocating/Monitoring Capacity
> ACHD/COMPASS/ITD coordinate to monitor
capacity
> Cities allocate capacity through development
approval process
➢ Central entity needed to consolidate
development tracking and capacity
allocations
1
Intended Consequences
> Capacity is coordinated with the generation of
new demands
> Capacity is coordinated with the ability to
maintain facilities
> Development is guided by capacity
> Congestion is managed
7
1
Unintended Consequence #1
CREATE INCOMPATIBLE/INEFFICIENT
CAPACITY
> Expand Facilities (real capacity)
> Reduce LOS standards (artificial capacity)
• Remedies
➢CIP coordination
➢Carefully crafted LOS standards
>Clear priorities for capital planning
Unintended Consequence #1
-V'AY TO LO'YYER -"C LEVEL
CF SERVICE ON THIS ,:ZO'?D, 3013"
Courtesy of Rich Unger, AICP
8
1
Unintended Consequence #2
DISCOURAGE INFILL AND REDEVELOPMENT
➢ Urban core roads already over capacity
➢ Limiting infill development will result in urban decline
➢ Widening roads can mean losing older, often historic,
buildings or neighborhoods
➢ Remedies
➢Adjust LOS standards (exception areas)
➢ Measure alternative capacity
➢ Limit capacity investment in rural areas
9
Unintended Consequence #
4/titailitigt
CAN ENCOURAGE SPRAWL
Roadway segments on the urban edge or in
rural areas are more likely to have an
acceptable LOS, which:
.Inceases travel distances
>Increases travel times
>Increases travel costs
>Increases congestion
>Increases demand for other facilities
10
increased Commute Distances &
Single Direction Commutes
11
Avoiding Sprawl Promotion
➢ Coordinate APF program
➢ Adjust LOS standards to tolerate less congestion
in rural areas
➢ Focus capacity investments to avoid sprawl
Unintended Consequence #4
INABILITY TO FUND ROAD MAINTENANCE
➢ APF requires ongoing funding for capacity
improvements and maintenance
➢ Maintenance shortfalls reduce capacity
➢ Mitigation and impact fees can only be used for
new capacity
➢ Remedies
➢Secure more funding
➢Ensure that growth pays for its share of
capital costs
➢Require mitigation projects to be included in
CIP
12
The Bottom Line
> Coordinated Transportation APF program can
help manage Tong -term congestion
➢ Uncoordinated Transportation APF program
will:
Discourage infill
>Promote sprawl
>Impair funding capacity
>Promote future blight in all areas
Specific Consequences of Failure
to Coordinate
➢ Ada County
➢ Increased service cost burdens
➢ Increased congestion between rural and urban
areas
➢ Limited alternatives to congestion
➢ Diminished funding capacity
➢ Boise
➢ Least impact — increased congestion
➢ Lost opportunities for needed facilities
13
Specific Consequences of Failure
to Coordinate
> Eagle
>Increased congestion
>Limited alternatives to congestion
>Lack of, or incompatible facilities
>Lost opportunities for needed facilities
➢ Garden City
>Lost opportunities for needed facilities
Specific Consequences of Failure
to Coordinate
> Kuna
>Increased service costs
>Increased congestion
>No alternatives to congestion
>Lack of facilities
>Lost opportunities for needed facilities
14
Specific Consequences of Failure
to Coordinate
➢ Meridian
➢ Increased congestion
➢ Lack of facilities
➢ Lost opportunities for needed facilities
➢ Star
➢ Very limited alternatives to congestion
➢ Diminished funding capacity
➢ Lack of facilities
➢ Lost opportunities for needed facilities
S*'
15
CG, -2o -o7
BOISE RIVER AFTER ACTION REVIEW
2006 HIGH WATER
VICINITY OF THE CITY OF EAGLE, IDAHO
Prepared for the
City of Eagle, Idaho
U.S. ARMY CORPS OF ENGINEERS
WALLA WALLA DISTRICT
MARCH 2007
BOISE RIVER AFTER ACTION REVIEW
2006 HIGH WATER
VICINITY OF THE CITY OF EAGLE, IDAHO
Description Page
EXECUTIVE SUMMARY 1
1. PURPOSE AND SCOPE 3
2. BOISE RIVER BASIN OVERVIEW 3
3. FLOOD CONTROL OPERATIONS GENERAL OVERVIEW 4
4. WHAT HAPPENED IN THE SPRING OF 2006 8
5. HOW THE 2006 FLOW SPLIT AROUND EAGLE ISLAND 13
6. ARE THE FEDERAL EMERGENCY MANAGEMENT
AGENCY MAPS CORRECT? 17
7. HIGH RISK/FLOOD SUSCEPTIBLE PROBLEM AREAS 18
8. IDEAS TO REDUCE RISKS 21
9. CONCLUSION 28
10. REFERENCES 29
TABLES
Table 1. Unregulated and Regulated Flows for Period of Record High
Runoff Events 6
Table 2. Unregulated and Regulated Flows for High Spring Snowmelt
Event Discharges 7
PHOTOGRAPHS
Photograph 1. Laguna Pointe Subdivision flooding 12
Photograph 2. View of irrigation push up diversion looking upstream from
head of Eagle Island. 14
Photograph 3. Looking downstream from end of irrigation push up diversion at
head of Eagle Island. 15
Photograph 4. South Channel Bridge on Eagle Road during spring 2006 peak
runoff 20
Photograph 5. North Channel Bridge on Eagle Road during spring 2006 peak
runoff 20
FIGURES
Figure 1. Comparison of Unregulated runoff and Regulated runoff at
Lucky Peak and New York Canal withdraws 10
Figure 2. Comparison of Unregulated runoff and Regulated runoff at
Lucky Peak and Glenwood Bridge. 10
Figure 3. Forecast Runoff Volume vs Actual Runoff Volume 11
Figure 4. Flows and flow split around Eagle Island during spring 2006 14
Figure 5. Historic flow splits around Eagle Island 1999 — 2006 16
i
Chart 1.
Chart 2.
Chart 3.
Chart 4.
Chart 5.
Chart 6.
Chart 7.
Chart 8.
Chart 9.
Chart 10.
Map 1.
Map 2.
Map 3.
APPENDIX
APPENDIX
APPENDIX
APPENDIX
APPENDIX
APPENDIX
CHARTS
Water Year 1983 Unregulated Inflow and Regulated Discharges
at Lucky Peak Dam
Water Year 1997 Unregulated Inflow and Regulated Discharges
at Lucky Peak Dam
Water Year 2006 Unregulated Inflow and Regulated Discharges
at Lucky Peak Dam
Water Year 1980 Unregulated Inflow and Regulated Discharges
at Lucky Peak Dam
Water Year 1993 Unregulated Inflow and Regulated Discharges
at Lucky Peak Dam
Water Year 1998 Unregulated Inflow and Regulated Discharges
at Lucky Peak Dam
Water Year 1992 Unregulated Inflow and Regulated Discharges
at Lucky Peak Dam
Water Year 2000 Unregulated Inflow and Regulated Discharges
at Lucky Peak Dam
Water Year 2001 Unregulated Inflow and Regulated Discharges
at Lucky Peak Dam
Water Year 2002 Unregulated Inflow and Regulated Discharges
at Lucky Peak Dam
MAPS
Basin Map
Downstream Eagle Island 1 percent chance floodplain
Upstream Eagle Island 1 percent chance floodplain
APPENDICES
A Official Correspondence
B Photographs of Laguna Pointe Subdivision Flooding
C Boise Project Office Response
D Permits
E Local Ordinances
F Williamson Ranch Eagle Island Proposed Floodway Revision
11
BOISE RIVER AFTER ACTION REVIEW
2006 HIGH WATER
VICIlVITY OF THE CITY OF EAGLE, IDAHO
EXECUTIVE SUMMARY
The U.S. Army Corps of Engineers conducted this After Action Review (AAR) at
the request of Eagle Mayor Nancy Merrill in a letter dated 18 July 2006. This letter,
along with subsequent communications led to this AAR that includes a summary of the
conditions and factors considered in the real-time decision making with the spring of
2006 Boise River Reservoirs operations, the flow split at the head of Eagle Island, a
review of the accuracy of the Federal Emergency Management Agency (FEMA) Maps,
identified flood susceptible problem areas (particularly bridges), and suggestions for the
community to consider for future flood risk reduction along the Boise River.
Flood control operations began 26 January 2006 in response to a 129% of normal
snowpack on 1 January that lingered in the Boise River Basin through January. Initially,
flows were increased to 4,000 cfs at the Glenwood Bridge gage by 8 February. Following
a drier February flows were reduced to 3,000 cfs at the Glenwood Bridge from 8 March
until 6 April. The first part of April came with heavy precipitation and a higher runoff
volume forecast then space was available in upstream reservoirs. In response flows were
increased to 7,000 cfs at Glenwood Bridge gage by 21 April, and maintained at that peak
to 16 May when the runoff volume had passed. The New York Canal reached peak
withdraws on 5 May, significantly assisting in flood control by carrying 22% of the peak
releases from Lucky Peak Dam. Without the timely irrigation withdraws, peaks at
Glenwood Bridge would have been 10,500 cfs. At the event end, regulation was
successful; reducing the natural runoff peak from 22,000 cfs to a regulated 7,000 cfs.
This flood was not a rare event, but the 9th time flows have exceeded 6,500 cfs at
Glenwood Bridge since the completion of Lucky Peak dam. And this year it was only a
matter of a different temperature pattern, a late season storm, or a delay in irrigation
withdraws that stood in the way of significantly higher flows! It is not a matter of "if'
but "when" will a 1 percent chance flood occur on the Boise River.
The flow split around Eagle Island varied with the changing flows. The flow split
increased with Boise River main stem flows from 30% to 50% in the South Channel until
mid-May when the percentages of the flow carried in the South Channel shot up as high
as 80% on the receding limb of the 2006 event. The trend in the last 7 years has indicated
when flows increase above 2,000 cfs that less flow remains in the South Channel. But
when flows in 2006 exceeded 3,500 cfs the split moved to a 50% split at the 7,000 cfs
peak. A predictable flow split cannot be guaranteed in the present natural state of the
River.
The FEMA Maps were developed for less frequent high flow events than
experienced in the spring of 2006. A check to determine if the 2006 high flows
(approximately a 10 percent chance flood) could be contained within the 1 percent
1
chance floodplain resulted in very few small localized areas of error. Also shown on the
aerial map overplots is that nearly all the Eagle Island moderate risk areas, Zone X, have
been completely constructed upon in the Eagle Road area. The flow split that was
determined for the FEMA mapping was not what was observed in the spring of 2006.
The reasons for this include environmental and human induced changes. A designated
floodway area needs to be defined downstream Eagle Road and the designated floodway
area near the Lemp Ditch needs to be maintained. While FEMA maps are developed
with substantial attempts to make them as accurate as possible, they are only a snapshot
in time. The maps offer no assurance that areas flooded will not change as a result of
erosion, deposition, movement of bed materials, changes in split flow, development, or
pit/lake/pond capture. The FEMA maps also make simplifying assumptions that include
no debris, bridge blockages, scour, or sand bagging.
There are multiple high risk areas in the vicinity of Eagle Island. The highest risk
areas are those of pond/pit capture, and the Eagle Road and Linder Road Bridges. The
associated risk of the pond/pit capture can be seen by the flooding at Laguna Pointe
subdivision, and how the effect of entraining flow can cause a new path for the river.
The potential change in the traditional flow split at the head of Eagle Island puts the
Eagle Road and Linder Road Bridges at risk. The lower assumed flow split to the South
Channel puts the bridges along that channel at the greatest risk.
There are multiple local and valley wide ideas for near-term and long-term
solutions for flood prevention. Solutions can be either structural or non-structural.
While this report is not intended to point the reader to a desired solution, it does provide a
brief overview of many options available. Many of the ideas presented may be quickly
dismissed if they do not meet the goals and objectives of the Treasure Valley
communities. But the fact is that there are no real good near-term solutions or quick
fixes. Putting great expense into localized fixes is usually not good economics. This is
why the Lower Boise River Valley needs to come together and develop a common vision,
a vision of the future of the Boise River. This vision can then be coupled with a plan to
implement a lasting solution to flooding concerns.
2
1. Purpose and Scope
The spring of 2006 brought the highest water surfaces that the Boise River has
produced since the spring of 1998. The long dry period from 1998 to 2006 was
encompassed with record growth in the City of Eagle, some in high risk areas adjacent to
the Boise River. As a result, the highwater experienced 2006 has triggered community
interest in flooding along the Boise River.
Whenever flooding or highwater events involve the U.S. Army Corps of
Engineers (USACE) expending over $500,000 in Flood Control Coastal Emergency
funds, the USACE is required to prepare an After Action Report (AAR) in accordance
with Engineer Pamphlet EP 500-1-1. While this was not the case in the 2006 high flows
on the Lower Boise River, in response to a letter by Eagle Mayor Nancy Merrill on 18
July 2006, Appendix A, the Walla Walla District, U.S. Army Corps of Engineers
(USACE) has prepared this report. The following sections address concerns outlined in
the 18 July 2006 letter and subsequent communications with the staff of the City of
Eagle. Included is a surn wary of the conditions and factors considered in the real-time
decision making with the Boise River Reservoirs operations in the spring of 2006, the
flow split at the head of Eagle Island, a review of the accuracy of the Federal Emergency
Management Agency (FEMA) Maps, and identified flood susceptible problem areas
(particularly bridges).
This report also provides suggestions for the community to consider for future
flood risk reduction for the citizens who live and recreate along the Boise River and those
businesses who may be concerned about the economic impacts that come with floods.
The intent of this section is not to lead the City of Eagle to any particular conclusion for
flood risk reduction but rather to provide information and ideas to best assist in the
decision making process.
2. Boise River Basin Overview
The Boise River originates in the Sawtooth Mountains and flows in a westerly
direction eventually joining the Snake River along the border of Idaho and Oregon. The
long basin axis trends east -west and includes large portions of Ada, Canyon, and Elmore
Counties and a small portion of Boise and Camas Counties. From headwaters in the
Sawtooth Mountains to the mouth, the Boise River travels a distance of about 200 river
miles with a total drainage area of approximately 4,130 square miles. Topography and
runoff characteristics naturally divide the Boise River Basin into two separate and
distinctive watersheds — an upper and lower watershed, see Map 1.
The upper watershed consists of approximately 2,680 square miles of drainage
area upstream Lucky Peak Dam. It is composed of precipitous mountains and
characterized by deep V -Shaped valleys, steep slopes, and narrow sharp top ridges. The
upper watershed ranges in elevation from 3,000 to 10,600 feet above mean seal level
(msl), and the mean elevation is approximately 5,800 feet above msl. The average annual
precipitation ranges from 15 inches to over 52 inches at the higher elevations. The upper
watershed contains the head waters of all the significant tributaries. The principle
tributaries are Mores Creek, South Fork, North Fork and Middle Fork.
3
The lower watershed consists of approximately 1,450 square miles of drainage
area downstream of Lucky Peak Dam. This area is composed of river bottoms, terraces,
and low rolling to steep hills with few distinct mountains. The average annual
precipitation ranges from 8 inches near the mouth of the Boise River to as high as 22
inches at the highest elevations on the hillsides. Adjoining the Boise River is bottom
land, varying from 1 to 3 miles in width, constituting the normal floodplain. Adjacent to
this bottom land is a series of two terraces that grade upward to the east to a ridge that
cuts the basin north and south at the approximate location of Lucky Peak Dam. This
ridge, known as the Boise Front, forms the boundary between the upper and lower
watersheds. Streamflow within the lower watershed is quite limited. The main tributaries
are Indian Creek, Willow Creek, and Dry Creek. These streams, except Indian Creek, are
intermittent and normally flow only during the spring and early summer months.
In the lower watershed the Boise River flows in a steep channel formed of
material which can be easily eroded and transported by the river. There is a noticeable
change in the average stream slope at Eagle Island with the average slope upstream of
Eagle Island being about 13 feet per mile and downstream of Eagle Island about 8 feet
per mile. In most reaches downstream of Boise, the channel cross sections continuously
change shape in response to erosive forces of water as material is eroded or deposited by
the river. The banks, composed mainly of silts and sands and some gravel, erode easily
at high flow, sloughing into the channel. Depending upon the quantity of flow present
and the size of the material, the material is either transported completely out of the basin,
or may be at least temporarily deposited on bars, or on islands.
Lucky Peak Dam, located just upstream the City of Boise, is one of three federal
projects operated by the USACE and U.S. Bureau of Reclamation (USBR) upstream the
lower Boise River Valley. While originally built for different purposes, these three dams
presently are operated as a system in an integrated, coordinated manner for
congressionally authorized purposes, including flood control, irrigation, hydropower and
recreation. Irrigation flows, diverted into canals early in the year, often complement the
flood control operation by allowing higher flows to be released from Lucky Peak Dam.
The most significant of these diversions is the New York Canal.
3. Flood Control Operations General Overview
The USACE and USBR jointly operate the Boise River reservoir system (Lucky
Peak Dam, Arrowrock Dam, and Anderson Ranch Dam) under formal flood control
criteria and rule curves. These flood control criteria and flood control rule curves are
contained in the publication entitled; "Water Control Manual for the Boise River
Reservoirs," dated April 1985 (with revisions). Flood control, irrigation, Idaho
Department of Fish and Game's space to maintain minimum wintertime flows and non -
contracted space for industrial uses at Lucky Peak Reservoir are the primary uses for
Anderson Ranch, Arrowrock, and Lucky Peak storage spaces. Because these dams are
managed as a multipurpose system, it is not possible to optimize regulation for each of
the separate uses. Thus, the Water Control Manual was developed with compromises
between the various uses, and flood control use directly conflicts with all other system
uses to some degree. Optimum flood control protection would require that reservoirs be
4
maintained empty and available to control floodwaters. Optimum irrigation use would
require that the system be maintained as full as possible to provide carryover storage
water for the drought years. The key Boise River system use conflict is that of flood
control versus system refill. The flood control rule curves given in the Water Control
Manual define a balance of flood control risks and refill assurances.
The USACE and USBR jointly developed the flood control rule curves. The rule
curves were developed to translate runoff volume forecasts to required system flood
control space. The runoff volume forecast is the key input in the rule curves and is
typically developed by USACE, USBR and the National Weather Service on the 1St and
15th of each month, January — July, to adjust for flood control and irrigation refill
requirements. During critical periods, runoff volume forecasts and subsequent changes to
releases can be made more frequently.
The Water Control Manual contains the flood control plan that is used for (1)
Winter Requirements (1 November —1 March, (2) Spring Evacuation Requirements (1
January through 31 March) and (3) Refill Requirements (1 April through 31 July). The
primary goals of flood control operations from 1 November through the spring high water
is to prevent loss of life and limit property damage due to flooding of the Boise River. To
accomplish these goals, the USACE and USBR coordinate flood control operations to
maintain adequate flood control space within the three Boise River reservoirs and yet
refill the reservoir system without exceeding the regulation objective of 6,500 cubic feet
per second (cfs) as measured at the Glenwood bridge gage. Flows of 6,500 cfs at the
Glenwood Bridge gage do result in some flooding and is considered to be the acceptable
damage flow level by the regulating agencies. 6,500 cfs is considered to be bank full
capacity and 7,000 cfs is considered to be flood stage for the Boise River at the
Glenwood Bridge gage.
Boise River unregulated annual spring snowmelt-event discharges in excess of
20,000 cfs (5 year flood) have occurred on 16 occasions during the 112 years from 1895
through 2006 at the Lucky Peak Dam location. (Unregulated runoff is what the natural
runoff would be without dams or irrigation diversion.) The following tabulation, Table 1,
summarizes unregulated peak discharges in excess of 20,000 cfs for the Boise River at
Lucky Peak Dam and regulated discharges as measured at the Glenwood Bridge gage.
(Regulated runoff is what discharges are from Lucky Peak Dam, but does not include
irrigation withdraws. The Glenwood Bridge gage includes irrigation withdraws.)
5
Table 1
Unregulated and Regulated Flows for Period of Record High Runoff Events
Unregulated
Peak
COUNT Date
1 14 -JUN -1896
2 18 -APR -1897
3 18 -May -1927
4 10 -May -1928
5 18 -Apr -1943
6 28 -Apr -1952
7 25 -May -1956
8 22 -May -1958
9 23 -Apr -1965
10 14 -May -1971
11 17 -May -1975
12 30 -May -1983
13 15 -May -1984
14 16 -May -1996
15 16 -May -1997
16 20 -May -2006
Unregulated
BOISE RIVER
AT
LUCKY PEAK
DAM
Maximum
April -July
Mean Daily
Peak
Discharge
(CFS)
35,500
29,500
20,060
20,710
25,040
23,430
22,950
21,750
20,850
20,250
20,620
24,290
22,540
20,570
22,160
22,065
Regulated
BOISE RIVER
AT
GLENWOOD
BRIDGE
Maximum
mu
April - July
Mean Daily
Peak
Discharge
(CFS)
Unknown
Unknown
Unknown
Un]aiown
20,500
7,790
6,600
6,320
7,170
6,850
6,680
9,560
6,900
6,680
7,020
7,050
Regulated
Peak
Date
19 -Apr -1943
27 -Apr -1952
3 -Apr -1956
29 -May -1958
22 -May -1965
16 -May -1971
27 -May -1975
13 -Jun -1983
4 -Jun -1984
26 -May -1996
4 -Apr -1997
8 -May -2006
Unregulated
April -July
Runoff
Volume
aUX1
2,677
1,542
1,982
1,577
2,694
2,251
2,231
1,898
2,557
2,457
1,850
2,324
2,007
1,939
2,332
2,062
April -July
Runoff
Percent
OF
AVERAGE
186%
107%
138%
109%
187%
156%
155%
132%
177%
170%
128%
161%
139%
135%
162%
143%
April -July
Water Supply
Description
Large
Near Average
Large
Near Average
Large
Large
Large
Large
Large
Large
Large
Large
Large
Large
Large
Large
Since the completion of Lucky Peak Dam, spring snowmelt-event discharges in excess of
20,000 cfs have occurred on 10 occasions between 1955 and 2006, with the highest
regulated flows of 13,200 cfs from Lucky Peak Dam and 9,560 cfs at the Glenwood
Bridge gage, on 13 June 1983.
The following tabulation, Table 2, summarizes April through July runoff for
large, near average, and low runoff volume years. These years provide a breadth of
examples of the variety of runoff patterns observed on the Boise River.
6
Table 2
Unregulated and Regulated Flows for High Spring Snowmelt Event Discharges
Boise River Boise River
At Lucky Peak At Glenwood
Unregulated Regulated
Maximum Maximum
1 Apr — 31 Jul 1 Apr - 31 Jul 1 Apr — 31 Jul
1 Apr —31Ju1 Runoff Mean Daily Mean Daily
1 Apr — 31 Jul Runoff Percent Peak Peak
Runoff Volume Of Discharge Discharge
Description Year (KAF) Average (CFS) Date (CFS) Date
Large 1983 2324 164% 24,290 30 -May 9,560 13 -May
Large 1997 2332 165% 22,540 16 -May 7,020 4 -Apr
Large 2006 2062 143% 22,065 20 -May 7,050 8 -May
Near Average 1980 1510 107% 12,960 7 -May 5,620 22 -Jun
Near Average 1993 1536 109% 16,720 30 -May 6,560 23 -May
Near Average 1998 1566 111% 14,190 27 -May 8,350 31 -May
Low 1992 415 29% 4,149 9 -May 830 2 -Jun
Low 2000 1069 76% 8,870 25 -May 3,330 19 -Apr
Low 2001 481 34% 6,210 16 -May 950 20 -May
Low 2002 1096 78% 14,220 25 -May 1,340 7 -May
In large runoff years, such as 1983, 1997 and 2006, maintaining adequate flood
control space within the reservoirs and passing excess water through the system without
unduly jeopardizing system refill, are the primary objectives. Chart 1, Chart 2 and Chart
3 show unregulated inflow for the Boise River at Lucky Peak Dam and regulated flow for
the Boise River at Glenwood Bridge for large runoff years 1983, 1997, and 2006 having
unregulated peak discharges of 24,290 cfs, 22,540 cfs, and 22,065 cfs respectively. These
charts show how regulation can remove higher unregulated runoff peaks and store or pass
the volume of water with lower peaks at Glenwood Bridge.
Near average runoff years, such as 1980, 1993, and 1998, require a delicate
balance between flood control and refill regulation, with runoff timing and volume
forecasts as the key factors for the balances. Chart 4, Chart 5 and Chart 6 show
unregulated inflow for the Boise River at Lucky Peak Dam and regulated flow for the
Boise River at Glenwood Bridge for near average runoff years 1980,1993 and 1998,
respectively.
In low runoff years, such as 1992, 2000, 2001, and 2002, flood control regulation
is normally not necessary and water conservation and reservoir refill are the operation
objectives. Chart 7, Chart 8, Chart 9 and Chart 10 show unregulated inflow for the Boise
River at Lucky Peak Dam and regulated flow for the Boise River at Glenwood Bridge for
low runoff years 1992, 2000, 2001, and 2002, respectively.
7
Effective flood control operations since 1955 have created a situation where most
local officials, developers, business and homeowners have never seen a large flood on
the Lower Boise River. In fact, many in the current population did not reside in the
valley during the largest post -dam high water event which occurred in 1983, when the
river reached 9,560 cfs at the Glenwood Bridge. The public perception seems to be that
flows over 4,000 cfs constitute a high water event, and that the discharge in 2006 of
7,000 cfs was a major event. The operations of Lucky Peak, Arrowrock, and Anderson
Ranch dams have effectively created prolonged periods where high water is not seen in
the Lower Boise River Valley. This is a result of the fixed storage volume that these
dams have available to reduce the peak flow during more frequent runoff years. During
rarer years, such as those generating greater than a 10 percent chance flood, the finite
storage volume in the upstream reservoirs may not be adequate to maintain peak flows
below flood stage, 7,000 cfs, at Glenwood Bridge.
The clock is ticking and it is not a matter of if a major flood (2 percent chance
flood to a 1 percent chance flood) will bit Boise, but rather a matter of when. In 1983 it
was only dry and cooler weather conditions in the midst of a May -June hot spell that
slowed the snowmelt runoff so that the Boise River reservoir system could regulate the
peak flow at the Glenwood Bridge to 9,560 cfs.
4. What Happened in the Spring of 2006
Snowpack, Runoff, and Operations
A higher than average snow pack accumulated in the Boise River Basin
throughout the fall of 2005. By 1 January the snowpack reached 129% of normal. This
above average snow pack lingered in the Boise River Basin through January due to
prolonged cooler temperatures. In response to the large volume of snow in the basin, the
USACE and the USBR began creating space in their reservoirs to "catch" the volume of
water that was still in the mountains.
In response to the higher than average runoff volume forecast (127% of normal),
increased reservoir releases began 26 January. Flows were increased 200 cubic feet per
second (cfs) per day until they reached a peak of 4,000 cfs on 8 February at Glenwood
Bridge. The 1 February snowpack and runoff volume forecast both reached 142% of
normal and supported sustained releases at 4,000 cfs. This flow release was well within
the normal year flood control release range, a range which extends to a regulation
objective of 6,500 cfs at Glenwood Bridge, see Figure 1.
Flows were held at 4,000 cfs at Glenwood Bridge until 8 March to create space
for the forecasted volume of water remaining in the Boise Basin. Considering drier
conditions (snowpack at 121% of normal) and adequate flood control space for the 1
March runoff volume forecast (133% of normal), releases were reduced to approximately
3,000 cfs at Glenwood Bridge from 8 March until 6 April.
The first part of April came with heavy precipitation and a higher runoff volume
forecast than space was available in the upstream reservoirs. Releases needed to be
ramped up to prepare for the peak runoff. The peak at the Glenwood Bridge gage was
just over 7,000 cfs. An attempt was made to limit flows at Glenwood Bridge to 7,000 cfs
(flood stage), and that peak was maintained from 21 April to 16 May when the runoff
8
volume had passed. The peak discharge from Lucky Peak dam was 10,500 cfs from 10
May to 17 May. Irrigation (New York Canal) began 29 March, allowing increased
releases from Lucky Peak without increasing flows at Glenwood Bridge. The New York
Canal slowly increased Boise River withdraws from an initial 500 cfs to a peak of 2,300
cfs on 5 May, significantly assisting in flood control by carrying 22% of the regulated
peak, see Figure 1.
A snow flight occurred 30 May 2006 that indicated less snow was over the basin
than was determined from the snow gaging stations. This resulted in change in the
volume forecast and a sharp correction (reduction) to the releases to assure refill for the
USBR. The correction turned out to be an overcorrection which then created a second
short duration peak of 6,500 cfs at Glenwood on 10 June, see Figure 1.
At the event end, regulation was successful; reducing the natural runoff peak from
22,000 cfs to a regulated 7,000 cfs, see Figure 2. It is important to note that irrigation
withdraws were responsible in reducing the peak at Glenwood Bridge from 10,500 cfs to
7,000 cfs. Presently, irrigation withdraws are not a part of the flood control plan and
cannot be relied on for future high flow peak reductions.
Figure 3 shows how the runoff volume forecasts compared with the actual runoff.
Generally speaking, runoff volume forecasts improve from January to March as the snow
pack builds.
Lessons Learned
During the spring of 2006, USACE employed the use of satellite imagery to
determine snow covered area. This worked well and should be continued in future
operations. Also, an additional snow flight earlier in the season would have helped better
guide runoff volume forecasts. This year also emphasized the need for a new Boise River
stream forecast model for Walla Walla District USACE.
9
Mean Dally Flow (cfs)
12,000
I I I I I t 1 1 I I I I I 1 t I I 1 I I 1 I I I
- + H - - I- + -t -i - I- 1- -1- -1 -1- I- + -1 -1 - 1- t 1- -I - 1- + H -1-
_ 1 J _, _ L L _1 _l _ 1_ L 1 J _1_ L 1 _1 _I _ I_ '•t_I _ I_ L 1 J _1-
10,000 ' 1 1 1 1 I 1 1 1 I 1 1 1 1 1 1 I Isz I 1 '• 1 1 1 1 I
_ + -1 -1- IH + -+ -I - I- 1- 4 H -I- 4 + -1 -I + H- -1" 4 ,f H -I -
- 1 J _I_ L L 1 _1 _ I_ L 1 J _I_ L 1 1 __11 I_ L 1 _I _te_ L'1+J _I_
I I 1 1 1 I 1 1 1 1 1 I r l 1 1 1• I I I I
0000
-i- -1 -1- I- - -+ H - I- 4- + -I -I- I- +--4'-I-J_ -I -I` I-'+ -I - I -
_ 1 J _I_ L L 1 _1_1_ L 1 J _I- L 1 r�l_1_ _ 1 •_' _I_L L J _1_
6.000, • •
1 1 1 1 1 I1• I++ 1 ,c
- + r
"' + —.1 —— 1 I— 4- -+ -I - i - 1- 4- - - 1 - 1- 4-1-} -1 - 1- - 4 -I - •- - 1 1 r+. -t N I -
_ 1 J_I _ 1_ L 1_1_1_ _ 1 J_ 1_ L S.1_1_1_ L 1 _I _ I-: L: '1 J
•
4,000 i 1 .3'^r•'+-r..•r-"` �' I 1 1 1 1 I 1 1 1 I ' 1 , 1 1 I
�crcr
4--I -1 - 1- y �-4 -I - I- 1- l .-,i...K + 4 -1 - I- 4- 4 -1 - I—'/ + '1 —1 —
_1J_I_I_kL1_I_i_L1 I_I 11_I_1_ 1 11 'I _I
2,000 _ 1 t t t ; -411
- -1 -I 4- 4 -I - I- 1-- + -1 - 1 - 4- 4- -I -I -,-I- 4- 4 -1 - I- 1- + -I - ...
a
. �L I_11_I_I_LTJ_I�_' ,_T 1_L1_1_1_L1:_I_
0
0 0
0 Oo Oa .NO O0D
00 0DO0
s62.
NNi Nd NT NAN g 2 Q R
o
r
N r N N N
N
1 -.
Lucky Peak Discharges
New York Canal Withdraws + Glenwood Bridge
4 -Jun -2006
18 -Jun -2006
Figure 1 - Comparison of 2006 Lucky Peak Discharges, flows at Glenwood Bridge and
New York Canal withdraws.
_ 1 J _ I _ I_ L 1 _I _1_ L 1 J _ I - L ' L 1 _I'� I _,.l 'L 2.1_ L, l 1 -I _
- t -1- 1- fi -r -I --1-- t- t -1 -I - t i' i' -1I - I- I I- _ 't -1-
25,000
1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
_ 1 J _I_ I_ L 1 _I _1_ L 1 J _1_ L L 1 _1 _1- L 1 J _i_ L L 1 _I _
-+1-I-I-t--t-1-1-r--1--rt--t--I-rti-1- t -1-
20,000 I 1 1 1 I 1 1 1 1 1 1 1 1 1 I I 1 19 1 1 1 1 1
--1--1-1-I- 4- 4 -I - I- I- 4- -I -1- I- 4 -4 -I -I-1- 4-1-1-I-4--+-I-
T1-1-1-r7-I-I-rT1-I-I-r-r 1-1± rT'-1'-I-r 7 --1
_ 1 J _l_ L L 1 _I _1_ L 1 J _I_ L L 1 _I,_JY L 1 J,_I_ 4 1 1 _1-
15.000 1 1 1 , 1 • 1 ,, 1
T1 -I -I- T7-I-I-ET7-I-I-1.rri7 1-1T7-1-
10,000 I I I 1 1 1 1 1 I 1 1 1 1 1.: 1 .11 L. L 1 .16'4,..1_01,_ +., 1 _I _
-+-1-1-1-4- 4-1-1-4+-1-1-I-4- 4:4•40LI-1--1---r- I--I'•t-1-1-
- T 7 -1- I- r 7 -1 -I- r T 1 -1- f T7,7,71 -741.-'17-i---.1. -I'a I -.r7 _I _
5,000 - 1 1 1 I 1 I 1 I 1 I 1 1 • T__. 1 1 1 I I 1 "!-.1 _ 1,^rY 1
7 t -1 -1 - I- tom-~:- - . `i--:, .=; -1 -1,r 1-. -f -1 - 1- 1- + -1 - I ; -1 -''11. 1.
1 1 1 I' I 7 -1 - 11- i"•+1..,• I,„.• 1 Y'':.'1 1 1 1 1 1 1 1 1 ••4 • 1 -1. 1
- .Lr=r -..4•'..51...„'k_ 4- T 4 - I - 1- _ 4 _1_1_ 1- 4_ J _1_ 4- 1 -4 -`i.-_•
0. _..•
.D ID .D W .D [D .D W 0 .D <D
O O 0 O O O O O 0 0 0
O O
0 0 0 O O 0 O 0 0
N N N N N N N N N N N
CC C d '- ' T T
- 7w u Q Q N 4r 11f N r N r N �' N
1
4 -Jun -2006 -
18 -Jun -2006
• Lucky Peak Unregulated Inflow, cfs • Lucky Peak Discharges, cfs • Boise River at Glenwood, cis
Figure 2 - Comparison of 2006 Unregulated runoff and Regulated runoff at Lucky Peak
and Glenwood Bridge.
10
3,000
2,500
2,000 --
o —
o _
o _
m 1,500 --
u. —
m
c)
1,000 --
500
0
1/1/2006 1/15/2006 2/1/2006 2/15/2006 3/1/2006 3/15/2006 4/1/2006 4/15/2006 5/1/2006 5/15/2006 6/1/2006
Forecast Date
IUSACE & USBR Forecast date -Jul KAF ❑Actuals for date -Jul Forecast Period KAF
Figure 3 — 2006 Forecast Runoff Volume vs Actual Runoff Volume
su,wea
2006
From 1 May to 13 May 2006 the USGS performed a prorated shift to the rating
curve at Glenwood Bridge. Conversation report dated 7 December 2006 with Jack Doyle
at the USGS indicated that the shift in the rating curve was due to channel movement and
scour at the new bridge that increased capacity. Releases at Lucky Peak Dam were
adjusted for the shift in the rating curve during May so that flows at Glenwood Bridge
were truly maintained near 7,000 cfs at the peak.
The spring 2006 peak flow of about 7,000 cfs was roughly equivalent to a 10
percent chance flood (10 year flood). Flows were maintained at this lower peak due to
aid from irrigation withdraws. Note that without the irrigation withdraws the peak would
have been 10,500 cfs, nearly a 2 percent chance flood (50 year flood).
What Happened in the Treasure Valley
When flows reached 4,000 cfs at Glenwood Bridge concerned citizens began
speaking out. Yards and outbuildings were getting wet, and some homeowners were
concerned for their homes. One developer even had his development inundate when
flows reached just over 6,000 cfs. These citizens were a relatively new group of persons
that were permitted to build in a known flood prone area. Many of these citizens knew of
the risks and past high water years, others were totally uninformed. The flood concern
for the Boise River area is generally summarized below in an excerpt from the 1985
USACE Water Control Manual (with revisions) for the Boise River Basin:
11
"Capacity of the Boise River channel through the lower watershed (Boise Valley)
varies between approximately 3,500 cfs and 10,000 cfs. At 3,500 cfs, a few small
areas are subjected to out -of -channel flow and are inundated. For flows up to
6,500 cfs at Glenwood Bridge, flooding is normally limited to pastureland, low-
lying farmland, gravel pits near the river, and a few buildings located directly at
the edge of the river. Flows in the 5,000 cfs to 6,500 cfs range do, however, result
in significant channel and bank erosion. Flood damages caused by flows within
the 5,000 cfs to 8,000 cfs range, represent an accumulation of bank and channel
erosion problems over a 50 mile river reach. Flooding and damages
dramatically increase as the flow levels increase above 10,000 cfs."
On 13 April 2006 at 2:30pm Laguna Pointe subdivision experienced flooding at flows of
2,800 cfs on the South Channel due to erosion of a riverbank. Nearby Branbury
Meadows Subdivision and others had great concern and residents began filling sand bags.
This flooding should be no surprise considering the above mentioned bank erosion that
frequently occurs along the Boise River. These areas were the former pastureland and
low-lying farmland mentioned in the Water Control Manual. Photographs were taken by
USACE personnel during the high water at the Laguna Pointe Subdivision as shown in
Photograph 1 and in Appendix B.
Thotograph 1 — Laguna Pointe Subdivision flooding 2006
See Appendix C - Boise Project Office response 14 April 2006 regarding the Laguna
Pointe breach and spring flooding. The flooding of the Laguna Pointe subdivision is an
example of infrastructure being flooded, while the presently undeveloped homes would
have all been built with first floor elevations above the flood waters.
12
Near the head of Eagle Island is the Lemp irrigation ditch. The diversion
structure at the head of that ditch is the point that flows begin to pass from the South to
the North Channels. When FEMA mapped the area they showed a bypass channel that
would carry 550 cfs at the 10 percent chance flood, and mapped a portion of the area
regulatory floodway. Modifications by irrigators have prevented the South Channel
flows from entering this bypass at flows seen in the spring of 2006, causing greater flows
to remain in the South Channel than otherwise might have.
Approximately 1 1/2 miles upstream Linder Road a riverbank overtopped along the
north bank of the South Channel. This overtopping allowed water to flow down a
diversion ditch near the South Channel and sheet flow to the north over farm land until it
was intercepted by another irrigation canal. The only thing that prevented this from
being a major catastrophe was that no homes were developed in this area. This was a
normal situation of the river accessing the floodplain.
5. How the 2006 Flow Split around Eagle Island
The flow split around Eagle Island varied with the changing flows. Figure 4
displays how the flow split behaved throughout the 2006 high water. The flow split
increased with Boise River main stem flows from 30% to 50% in the South Channel until
mid-May when the percentages of the flow carried in the South Channel shot up as high
as 80% on the receding limb of the 2006 event. The change in flow split may have been
caused from a combination of many factors including: development immediately
downstream, quarry development, shifting in the streambed gravels, movement of the
push up diversion that irrigators have typically placed at the head of the island (see
Photographs 2-3), and sediment and debris washing into the North Channel. Further
development that changes the topography in the 1 percent chance floodplain near the
head of Eagle Island will further change the flow split.
13
16,000
1 L 1 1 L' 1' L L J -i- I- 1 J -I -I- L L- J-
_ 4 J- 1- I- 4- 1 -1 --- L 1 J 1 ' I I I- 1- -'- -I -
14,000 I ;
V
-r 1 -1 - 1 - 1- L 1 -1 - 1- I- L 1 -1 -1- 1- 1- 1 -f -I -1 - t- - 1- p -1.
12,000 r Z --1-I- r T -f -1-1- r 1- 7 7 71 7 1- r T 7 71-I-1rir T 1
6
- a--4- -
I -1 -I -l4 !
- -1-1-1- -4-1-I-I-I---4_-1-I-I -1-6if4-1
10,000 - + -4 H - I - i- t- + -4 -1 - I - - 1- 1 -1 -1 - 1- 1- + -1 -I -14 H I
F = t -r -1 -1- 1- r t 1 -1 - 1- 1 t- i -I -1 - I- r t -t -r'r' I - I -j 1 -t
0 = i 1 -I= - 7 T 7 -I -I- C L - =1..1r..2. 1 717 C 1-1
8,000
-4- - ---I - I - 1 4- -1- `„-1.- I -.. 4-,4 ---I .:f 1 - I- t- = --1 -1 - i - - � 4 --I
LL - + -+ -I141- 1- + -I -I - I - I- -I- -r"� - I - 1 1-'- 'f' "I - I - I- +- + -1
6,000 y'f ,,. 1- _ �- -
1 1 717 1= L I 71 7.1= E L 1 //1.1111 E 1 L 7111:E 1.\. 2
4,000
7r"
A
4
- + -f - - I - : - - L + -I -I •1- 4- 4 H -1 - I- r 4 r -I
2,000 - t- t - - 1 7 1- - t 1 71 - 17 h t' r- -t - I 7 I- r t 7 -I - 1- 17/it'
' • :r• -1
L I. -I- L�-1-I-I-1-1--4-I-I-I-I-4-- -I-I-1-4- 4 -
co co co com co co co co co co
o o 0 0 o c0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0
N N N N N N N N N N N N
c c c a a n a >. i. C
U ▪ LL Q Q g
N c0 N cD O) � n 7
1
2
2
i
1
- - SOUTH CHANNEL FLOW
---- PERCENT SPLIT TO SOUTH CHANNEL
e
2
-----••GLENWOOD BRIDGE FLOW
Figure 4 — Flows and flow split around Eagle Island during spring 2006
18 -Jun -2006
90%
80%
70%
w
z
50%
0
40% Z
1-
Z
30%
C
w
a
20%
10%
0%
Photograph 2 — View of irrigation push up diversion looking upstream from head of
Eagle Island, 2002.
14
Photograph 3 — Looking downstream from end of irrigation push up diversion at head of
Eagle Island, 2002.
Historical flow splits (Period of record: November 1999 — May 2006) for flows
between 1,100 cfs and 3,300 cfs at Glenwood Bridge have varied from 35% to 71% in the
South Channel at Eagle Road, and have changed with the time of year. The trend shows
that as flows increase above 2,000 cfs that less flow remains in the South Channel. But
as flows in 2006 exceeded 3,500 cfs the split moved to a 50% split at the 7,000 cfs peak.
The 2006 flow splits under 3,500 cfs are consistent with the 1999-2006 historical flow
splits with the exception of the June time frame when they exceeded 80% in the South
Channel as flows receded, see Figure 5.
15
Percent of Discharge In Boise River South Channel
100C
80 0
60 0
40 0
20 0
D0
0
Nov 1999 • Jan 2006
Feb 2006 • June 2006
Note: Percent of flows to the South channel increased with increasing flows until near
the peak of 2006.
As 2006 flows peaked and flows receeded, the flow division to the south channel
increased. The changes in the flow split can be contributed to a combination of natural
and human induced causes.
1,000 2,000 3,000 4,000 5,000
Discharge In Boise River (efs)
Figure 5 — Historic flow splits around Eagle Island 1999 — 2006
6,000
7,000 8,000
Schwarz
2006
The flow split at the head of Eagle Island is dynamic and ever changing. Most of
the change is due to irrigators controlling the low flow split, but the split also varies as
flows increase. The river gradient also changes near the head of Eagle Island depositing
material as the river slows. In July 2006 USACE received a letter from Mr. Scott
Campbell with Moffatt Thomas on behalf of Pioneer Irrigation District. They informed
USACE of the accumulation of a large gravel bar at the head end of Eagle Island and
stated that this gravel bar not only affects their diversion but could also increase over
bank flooding in the area during spring high flows. They asked for cooperation from
USACE and assistance in dealing with this issue. This accumulation of material is a
typical example of the material naturally deposited by high flows and moved by irrigators
that continually changes the low flow split for irrigation.
The peak flow for the 2006 spring runoff was 7,050 cfs, which is approximately
the same as the 10 percent chance (10 year) flood on the Boise River, 7,200 cfs, as
indicated in the effective FEMA Flood Insurance Study (FIS). The computer modeling
performed for the effective FIS indicated the 10 percent flood had a flow split of 31
percent in the South Channel at Eagle Road. A 50 percent flow split at roughly the same
peak was observed in 2006. This does not mean that the computer modeling and FEMA
hydraulic computations are incorrect. The flow split at the head of Eagle Island is ever
changing, and the associated risk on either the North or South Channel can be different
from the risk on the main stem Boise River. In the case of the 2006 runoff peak, the
South Channel had a peak flow of 3,500 cfs, which would be approximately a 2 percent
chance (50 year) flood at Eagle Road on the effective FIS.
16
The flow split also changes in the mid-section of the island where water can cross
over and rebalance on rarer high flow events (ie: 1 percent chance flood).
6. Are the Federal Emergency Management Agency (FEMA) Maps
Correct?
FEMA maps plot the 1 percent chance flood (Base Flood), Floodway, and 0.2
percent chance flood. Both the runoff events displayed on the FEMA map are for flood
flows more than double that seen in the spring 2006 runoff. The 2003 Flood Insurance
Study (FIS) for Ada County reports the 10 percent chance flood as 7,200 cfs, but does not
provide the floodplain boundaries for this return interval. The 2006 spring runoff
provided a limited opportunity to check the FEMA maps for accuracy against an actual
event.
The FEMA 1 -percent chance flood boundaries were overplot on the 2006 aerial
flood photographs. This is the best available check on the accuracy of the 2003 FEMA
Flood Insurance Rate Maps (FIRM's). The check was to verify that the 2006
approximate 10 percent chance flood did not exceed the boundaries of the 1 percent
chance floodplain on the FIRM, as one would expect. Maps 2-3 show this overplot.
Discovered were multiple areas where the pits have been enlarged or residential ponds
created that would extend the 1 percent chance flood boundaries. The north side of the
South Channel in the vicinity of cross sections Q and R had water outside the 1 percent
chance floodplain boundary.
The 2003 FIRM floodplain boundaries were compared with 2 foot contour data
created in 1998 by Towill, Inc. No discrepancies were found between the contour data
and the floodplain boundaries of the 1 percent chance floodplain, with the exception of
the areas with newly created ponds or enlarged quarries.
The floodway that was defined near the head of Eagle Island in the vicinity of the
Lemp Ditch, may not function as intended on the FEMA mapping due to irrigation
operations and modifications to the area and a quarry development. This floodway
transferred 550 cfs and 675 cfs for the 10 percent flood and 1 percent flood, respectively.
This was a questionable area to define a floodway due to the irrigation and quarry uses in
the area, and the constantly shifting flow split at the head of the island. This area either
needs to be maintained as a dedicated floodway or another area should be considered as a
dedicated floodway location to mitigate for the loss of floodway. Due to relatively little
topographic relief in the Eagle Island area another floodway location could be created in
another location near where it is presently mapped.
Downstream of Eagle Road there are areas where the predominant flow balance
crosses overland from the North Channel to the South Channel and back during the 1
percent chance flood. This area has no defined floodway. This presents a conflict as the
model was developed with a floodway exchange from the North Channel to the South
Channel and further downstream from the South Channel to the North, but provides no
dedicated floodway for these flows. The model or the mapping should be revised so that
either a mapped floodway is defined across the island, or the floodway flows in the model
reflect no exchange in this area. The 1 percent chance floodplain totally encompasses the
island in this area and an interchange floodway path may not be definable.
17
There is confusion by some who review the Ada County 2003 FIRM Maps. The
complaint is that there are significant errors in the present FIRM Maps. These apparent
errors can generally be explained by reviewing the events that led up to the 2003 FIRM
Maps. The FEMA study for Ada County (Boise River) was performed in the late 1990's
and a set of preliminary maps were generated in 1999. These maps were not immediately
adopted by Ada County and its communities. Due to the broader floodplain shown on
these maps, as compared to the previous maps, there was a rush to develop the areas that
would soon be changed to floodplain when the mapping was adopted. Significant
revisions were made to the FEMA mapping as a result of this development and the 2003
FIRM Maps subsequently had a change in the cross section numbering/lettering used. No
new cross-section cross-reference table was generated to tie the computer model with the
FIRM Maps. As reviewers first glance at the model, mapping and what they see and
know in the field, they see errors. But careful review of the model and mapping will
show that there was a change in the model and map numbering and lettering. When the
model numbering and map lettering are aligned most, if not all, of the perceived errors
will be clarified.
Most importantly, it should be noted that FEMA maps are made for assigning
flood insurance rates. While there are substantial attempts made to make these maps as
accurate as possible, they are only a snapshot in time. The maps offer no assurance that
areas flooded will not change as a result of erosion, deposition, movement of bed
materials, changes in split flow, development, or pit/lake/pond capture. The FEMA maps
also make simplifying assumptions that include no debris, bridge blockages, scour, or
sand bagging.
7. High Risk/Flood Susceptible Problem Areas
The Eagle Island area is the first reach of the Boise River below Lucky Peak Dam
with restricted channel capacity in a developed area. This makes Eagle Island the highest
risk area along the Boise River corridor. For this reason, this area is used as the point of
flood control regulation (Glenwood Bridge gage) for the Boise River reservoirs. Recent
development on Eagle Island has increasingly made Eagle Island the first Boise River
area to have flooding concerns as the river rises.
Adding to the lack of conveyance capacity that is available in the combined North
and South Channels is the potential of pit and lake capture. Current and former quarries
and beautiful neighborhood ponds are easy targets for the Boise River at high flows.
These target conveyance areas can capture and entrain flows if their surrounding
protective high ground were compromised. The quarries that have been developed along
the Boise River have push up berms surrounding them to prevent pit capture. These
berms have uncertain structural and erosion control design. The ability to have pit
capture of the Boise River puts many residential areas at high risk. Once entrained, a
third channel of the Boise River could be created, likely jumping from pond to pond until
it found its way back to either the North or South Channels. These high risk areas exist
along both the North and South Channels, and particularly on the island.
The highest risk areas for pit and pond capture are at the head of Eagle Island, and
along the south side of the South Channel just upstream the sewage treatment plant. The
18
berms that surround the ponds at the head of the island are not certified as adequate to
withstand high flows on the Boise River. This area receives the brunt of the rivers force,
as this is where the river bottom slope changes and the flow is divided between the North
and South Channels. Once flows are entrained in these ponds the downstream effects
would spell disaster as the flow jumps from pond to pond and move into the subdivisions.
If flows are captured by these ponds, the best situation that could occur would be for the
water to escape back to either the North or South Channel. It might be prudent short term
thinking to create a low point in the berms at the downstream end of the ponds so that
water would outlet in the desired flow direction. This solution does not address the
hydraulic complexities involved in pit capture but it would be a quick fix to reduce the
risk of creating greater flooding through pit capture. The Laguna Pointe Subdivision
flooding illustrates the potential of pit capture.
The bridges at Eagle Road are also high risk areas of limited flood flow capacity,
particularly those over the South Channel. The Eagle Road South Channel Bridge and
North Channel Bridge are shown in Photographs 4 and 5, respectively. The Eagle Road
Bridges pass the 1 percent chance flood assuming a FEMA defined 25%-75% flow split
in the South Channel and North Channel, respectively, without causing upstream
flooding. As the 2006 spring runoff demonstrated, the flow split can change. Since the
South Channel Bridge capacity is the smaller portion of the flow, it is potentially the
higher risk structure, although neither bridge has capacity to adequately take the entire 1
percent chance flood without causing upstream flooding. The Linder Road Bridges have
greater capacity than the Eagle Road bridges without causing out of bank flooding. Their
capacities are proportioned with a 1 percent chance flood FEMA defined 50%-50% flow
split. Despite the greater capacity of the Linder Road Bridges, neither of these could
individually convey the 1 percent chance flood without increasing upstream flooding.
All four of these limited capacity bridges could cause significant flooding of adjacent
areas if they were to become plugged by debris, or if flows exceed their capacity. As
seen at the Eagle Road South Channel Bridge, the 2 percent chance flood puts it near
capacity. Beyond the FEMA defined flows, the bridges ranked from least to greatest
additional available capacity are Eagle Bridge South Channel, Linder Bridge South
Channel, Eagle Bridge North Channel, and Linder Bridge North Channel.
19
?hotograph 4 — South Channel Bridge on Eagle Road during spring 2006 peak runoff
h� fr • i r'- *l xt 4 '4b t A,•�Y), a�- 1 '' v • ,/ fy •7tA py.
7'h94 F -: r'np,� +-e... f,
.k fix :ms's' �a�• :i -1:'434.7..?..,, ,,-.. ^,Y . 7d: 104s+i :-:.a.s ,as • } '' ` - i...
Photograph 5 — North Channel Bridge on Eagle Road during spring 2006 peak runoff.
High risk areas include homes and infrastructure that were built within the 1
percent chance floodplain. On the 2003 FIRM maps the 1 percent chance floodplain is
20
broken into two areas. The first is the defined Zone AE with base flood elevations, and
the second is the shaded Zone X with areas of less than 1 foot of depth or protected by
levees. Homes and infrastructure in these two areas have increasing risk as more areas
are developed within the floodplain. Those with the greatest risk are in the Zone AE.
These areas can be seen on 2003 FIRM Maps Numbered 16001C0134H, 16001 C0141 H,
16001C0142H, 16001C0153H, 16001C0154H, 16001 C0161 H, 16001C0162H,
16001 C0166H. The areas of high density are of great concern and are located on the
2003 FIRM throughout the Eagle Island Area, between cross sections D through E on the
main stem, M through 0, Y through AB, and A through E on the north side of the North
Channel, between cross sections A through C and G through P on the south side of the
South Channel, in the vicinity of Eagle Road on Eagle Island, and between cross sections
AN to AP on both sides of the river. These locations can also be seen on Maps 2-3 in this
report.
8. Ideas to Reduce Risks
All across the country communities have been wrestling with how to protect their
citizens, businesses and infrastructure from the destructive forces of flooding. Decades
ago local governments were eager to have their engineers find the quickest way to move
the flood water through their communities as quickly as possible or to build dams to
better control releases of flood water into downstream river corridors.
Many of these same local communities now realize that those and similar options
for reducing flood risk, while effective under certain design flows, also comes with high
costs for operation and maintenance, environmental mitigation, unintended adverse
impacts to natural river functions, as well as the equally unintended and extraordinarily
high cost in human suffering and property/economic losses when these structures exceed
their design lives or capability and fail.
The citizens and government of the City of Eagle are actively pursuing ideas and
solutions that would help reduce flood risks for future development, or at least maintain
but not worsen the present flood risk for existing structures. With that effort, they also
realize that there are a significant number of newly built structures that now exist in
harms way. Letters initiating this process are included in Appendix A.
There are solutions to these challenges; however, the process will require a
substantial investment of community time and possibly capital investments. The
Treasure Valley Partnership and the City of Eagle are actively engaged in defining new
flood ordinances that would allow for more sustainable solutions to reducing flood risks.
This is a very positive and proactive beginning.
The next step for the Treasure Valley communities situated along the Lower
Boise River is to develop their collective vision of what they want the Boise River to look
like in both near-term and into the future. If the vision is to preserve, protect and/or
enhance the functionality of the river corridor, then it becomes the community's
responsibility to develop that vision and establish a set of realistic goals and objectives
[alternatives] that would help local governments begin the process to make that vision a
reality. It is from that point that the community can then begin its relationship and
reliance on engineering/scientific analysis and economic feasibility.
21
The following are suggestions to reduce flooding risks in the Lower Boise River
Valley.
A. Preparing for Future High Water Events - Emergency Responders
There are a variety of things emergency responders can do to relieve risks.
Participating in regular table top exercises such as those hosted by Ada County, USBR
and USACE will keep responders up to date with procedures and coordination.
Developing evacuation plans for flood prone areas and alternate plans if the primary
routes fail is essential. Emergency Responders should maintain up to date contacts and
stay in contact with Local, State, and Federal governments when flows have a potential of
exceeding 7,000 cfs (flood stage). Regular checks should be made to assure that flood
response easements are maintained accessible.
B. Visual Inspections and Bank Monitoring
One very inexpensive way to stay on top of potential failure points along the river
would be enlisting local community volunteers to walk the river periodically to inspect
and record the condition of the banks, irrigation diversions, bridge abutments, and other
places where failure could occur. These types of inspections should be done at the "low
water" time of year because more of the bank structure would be exposed.
C. Sand bagging in the FEMA designated floodways
Sandbagging or filling in FEMA designated floodways to any level is not a
recommended option. Impeding the hydraulic functions of these designated floodways
can increase the potential of changing river course and overtopping downstream river
banks. Using this as a flood fighting tactic can and does produce catastrophic results.
The USACE strongly suggests that the local community contact their first responders for
proper advice and direction on where and when to place sandbags to protect their
structures, homes and businesses from rising flood waters.
D. Permits and Flood Repairs
During and following flood events it is very important to obtain permits. The purpose of
the permit process is to assure that the intent of the work is in the publics' best interest,
and will not create undue hardship on another citizen. Permits are a part of assuring No
Adverse Impact. An excerpt from a Walla Walla District USACE Public Affairs news
release is shown in Appendix D.
E. Structural and Non -Structural Flood Risk Reduction Alternatives.
There are wide variety alternatives that communities can consider to reduce flood
risk potential. These alternatives come in two categories; structural and non-structural.
Each category has its own associated set of benefits, costs and tradeoffs that a community
needs to consider in its decision-making process. At a minimum, benefits can be
22
generally characterized by: a dollar range of the community assets no longer at risk from
a specified probability of flooding; environmental values gained or lost; range of costs
associated with operation and maintenance of flood works; probability of replacement or
design upgrade costs for flood control works; water quality improvements or Losses;
recreational value gains or losses; as well as secondary sociological and economic values
gained or sacrificed. Various combinations of the following alternatives have been
implemented or are currently being evaluated in flood prone communities all across the
nation. For ease in reference these Non -Structural and Structural Alternatives have been
grouped by their near-term or long-term implementation, duration of lasting benefits, and
localized or valley wide application.
Non -Structural Alternatives.
Near -Term Solution with Limited Duration Benefits
a. Excavating additional channel capacity in the Lower Boise River: There has been
significant discussion by local citizens recalling the days when river bottoms were
widened and manipulated in an effort to gain additional flow carrying capacity to
the river. While this "clearing and snagging" practice can be traced back to the
early 1700's in this country, it has been done at great cost to otherwise healthy
river systems. These destabilizing alterations done decades ago now require a
significant pubic/private investment of time, money and other resources to
correct. Today's practice engineered river modifications involve sophisticated
modeling as well as other design techniques and considerations to insure that the
end product yields river system improvements that are healthier and more
sustainable over time.
Flood Control District 10 does have an annual program or routine
maintenance to cut down and remove fallen trees and other snags within their
jurisdictional boundaries. While downed trees along the river bank do not
generally cause changes or exacerbate flood water surface levels, they can cause
catastrophic damages if they dislodge from the bank are allowed to block bridges,
irrigation diversions and other man-made structure in and around the river. River
modeling done by the University of Idaho several years ago demonstrated that if
the Glenwood Bridge had a 20% blockage caused by trees and other floating
debris, it would actually backup the base flood event (1% chance event of 16,600
cfs) and create flooding in areas designated by FEMA as the 0.2 percent chance
floodplain (500 -year). Downed trees are also a major safety concern for
recreational floaters and boaters in the river as well as the teams that engage in
river rescues.
Near -Term Solutions with Long -Term Benefits for Localized Areas
b. Preservation and conservation of the morphological floodplain: While not always
doable in urban areas because of development encroachments into the floodplains,
this alternative is the overall least cost of all structural and non-structural
alternatives where land is readily available and can provide efficient and effective
spread and distribution of flood waters. Additionally, this alternative yields the
greatest flood risk reduction benefits in the proximity of the application. Many
23
communities across the country use these floodplain open space "set asides" for
multiple purposes such as greenbelts, parks, sports complexes, golf courses,
wildlife refuges, etc.
c. Land swaps and zoning densification: Exchanging the development rights for
flood prone river bottom land for uplands is also a very inexpensive investment
alternative when compare to the costs associated with flood damage recovery.
Lands could be exchanges could be conducted through a land exchange "bank"
similar to the now common practice of wetlands banking".
d. Buyout of "at risk" property and restoration of those properties back to natural
flood plain functions: While a somewhat more expensive option, it does offer the
avoidance of repetitive failures. FEMA offers a buyout assistance program which
includes community financial assistance.
e. Acquiring emergency access easements: The City and County should consider
obtaining easements for emergency access (a good reason for a 100 foot floodway
set back ordinance) for emergency flood fight activities, and after event repairs.
Near -Term Solutions with Long -Term Benefits for Undeveloped Areas
f. More restrictive floodplain codes and ordinances: Consideration of this very cost
effective alternative is already underway by the Treasure Valley Partnership.
Appendix E lists the present ordinances of the Treasure Valley Communities. A
couple of suggestions for code and ordinances include: No Adverse Impact, A
green belt ordinance requiring a 100 foot setback for structures from the
regulatory floodway, and prohibiting future structural development in the 1
percent chance floodplain without a flood mitigation plan. Currently citizens must
build homes elevated above the 1 percent chance floodplain but this does not limit
the waters abilities to flood streets, yards, outbuildings, and infrastructure. These
losses are still possible and the responsibility of the property owners and the City
or County to repair.
g. Development of a comprehensive. multi -objective master plan for the Lower
Boise River and its tributaries: This plan could embrace the vision, goals and
objectives of the Treasure Valley Community and act as a "User's Manual" for all
who share in the resources that the Boise River and its watershed provide.
h. Cumulative impacts assessment database: The Treasure Valley should work to
develop a single database for monitoring and evaluating the cumulative impacts
of filling and building in the Boise River floodplain. This would also facilitate
the evaluation of the associated water surface rise as a result of development
activities. This effort needs to be Treasure Valley wide.
Near -Term Solution with Long -Term Benefits for Entire Valley
i. Modifying Reservoir Operations: Changing water control operations is a method
to prevent increasing flood risk. The Boise River's channel capacity becomes
restricted over several years of drought because gravel bars form within the
channel and brush grows in the channel and on the banks. For example, the 1993
April -July runoff was 109 percent of average and the unregulated inflow of
16,720 cfs at Lucky Peak Dam was regulated to 6,560 cfs at the Glenwood
Bridge. The 1993 flood event followed a series of low flow years from 1987-
24
1992, with regulated flows generally less than 1,200 cfs at Glenwood Bridge, and
flooded many areas where flows of 6,500 cfs had not caused flooding problems
before.
Channel capacity has declined with regulation of large flow events in
excess of 20,000 cfs that would have flushed out and reduced vegetation within
the channel. However, high releases near the 6,500 cfs bankfull capacity at
Glenwood Bridge appear to recover channel capacity. For example, from 1995 -
1996 the Boise Basin experienced high flows of 5,000 cfs to 7,000 cfs at
Glenwood Bridge, that evidently flushed out and reduced vegetation within the
Boise River's channel so that the 1997, 1998 and 1999 flood flows of 7,020 cfs,
8,350 cfs and 6,650 cfs, respectively, had less flood impacts than the 6,560 cfs
flow in 1993. However, localized flooding problems can still occur at flows
below the bank full capacity of 6,500 cfs at the Glenwood Bridge, when a tree
blocks a channel, a dike fails, or a dike is constructed or altered. Without a
comprehensive and continuing maintenance program, it is expected that gravel
bar, tree, and brush accumulation within the channel will continue. Annual
flushing of the channel with high releases near bank full capacity of 6,500 cfs at
the Glenwood Bridge may slow and somewhat reduce this type of accumulation
in the channel.
Structural Alternatives.
Near -Term Solutions with Limited Duration Benefits for Localized Areas.
a. Soft armoring bank protection: There are numerous ways to repair and stabilize
eroding river banks with the use of living and non -living vegetation and other
bioengineering materials. If properly designed, these types of solutions work well
under certain flow conditions. Where flow conditions can cause scour, a mix of
hard and soft solutions can be a more environmentally friendly alternative then
hard armoring.
b. Rip -rap barbs/J-Hooks: One of the most common treatments that local
communities and land owners use to deflect river flow away from eroding banks
is the installation of rip -rap barbs. These projections are typically constructed of
large stones worked or placed into the river with heavy construction equipment.
In general they work very well to retrain flow away from areas of river banks
susceptible to failure. However, they do require engineering forethought and
careful consideration for placement, how they are aligned and shaped, the size of
the rock, and the range of flows under which these structures are intended to
operate. Nearly all barb designs need to also consider the adverse impacts of
retrained flow on opposite downstream banks of the river.
Long -Term Solutions with Long -Term Benefits for Localized Areas
c. Bridge Replacements: The Eagle Road Bridge across the South Channel has
limited capacity as observed this year. The local government should consider
evaluating the actual capacity of this bridge as well as others along the Boise
River that appear to have similar problems. If these bridges are determined to
25
have limited capability to pass high water, the local government would have
valuable information to prioritize the replacement or upgrades necessary to reduce
the risk of backwater and debris plugging. Along with this, the local governments
might consider the installation of reinforced concrete crane pads on the upstream
side of the bridges to facilitate debris and blockage removal.
d. Near -river levees (earthen and stone rip -rap): These types of levee design can be
best exampled by those constructed in Lewiston Idaho along the Snake River or in
the mid -west along the Missouri and Mississippi Rivers. Typically constructed
with a hardened (stone rip -rap) toe extend some distance upward along a slope or
incline, this type of structure can provide excellent flood risk reduction but at a
sacrifice to the "quasi -natural" river functions that are currently valued and
enjoyed along the Lower Boise River. In some cases, such as St. George, UT, an
alternative utilized for the recovery from flood damage events prescribed that the
river banks be fully rip -rapped with erosion control matting and stone overlay.
Stone rip -rap solutions, while widely -requested by local communities to fight
floods and stabilize weak points along banks, generally offer little to no
environmental benefits. In fact, hard armor techniques are considered by many to
have little value for fisheries, wildlife, water quality, and aesthetic appeal.
Within this alternative, the community could undertake the professional
evaluation (or verify if certifiable) the existing levees along the Boise River. If
these levees are "federally" certifiable, then new levees could be extended
connecting to the existing levees, and provide protection for the areas adjacent to
the Boise River. If the existing levees are not certifiable, then they could be
removed and all new levees could be built. Also, if the existing levees are
certified then they could be recognized on the new FEMA maps.
Although this idea may appear a simple fix, it has a number of detractors.
The levees would significantly reduce the natural values currently enjoyed along
the river margin. Private properties are in many cases built so close to the river
that many residences would have to be acquired, demolished and removed to
make room for the levee construction. The operation and maintenance component
of federal certification would require that the levee be maintained by prohibiting
trees and other large vegetation to grow on the levees, destroying the canopy over
the existing channel. There would also be a need for access easements. In
addition, any levee development could serve to increase flooding for downstream
properties.
e. Concrete channels [vertical and trapezoidall: This option does require the least
amount of land to design and construct, however, it also comes with a substantial
budget requirement for operation and maintenance. While the environmental
impacts of this type of solution can be substantial there are other combinations
and variations of designs where levees can be constructed with small profile
concrete barriers imbedded in the top of a levee.
Long -Term Solutions with Long -Term Benefits for Undeveloped Areas
f. Set -back levees with terraced peak flow channels: Compared to the non-
structural conservation of the morphological floodplain alternative mentioned
above, the design of this type of flood control works typically requires less land
26
for construction. However, these types of levees do require more land than other
structural flood risk reduction alternatives. One of the notable benefits from this
type of design comes from allowing the river to meander "somewhat" naturally
between the levees. Many of the existing environmental benefits can also be
preserved and protected as well. This type of design also allows for off -channel
"terracing" of peak flood flows. The City of Boise along Parkcenter Blvd and the
Phoenix Arizona Metro area are two examples where this alternative has been
implemented successfully. This concept will be examined during the feasibility
study stage as part of the improvements contemplated for Eagle Island State Park.
Typically, set -back levees require the least amount of operation and maintenance
costs, but often a significant cost in real estate procurement.
Long -Term Solutions with Long -Term Benefits for more frequent high flow events
(ie: 10 -percent flood)
g. Flow Split Control: The flow split at the head of Eagle Island is constantly
changing If a constantly maintained flow split at the head of Eagle Island is
desired a structure could be constructed to provide that flow split. The structure
would come at a high cost and would require regular maintenance and potentially
some channel capacity alterations from the entrance of the North Channel for
several hundred feet downstream. This would not relieve the problems with water
flowing across the island further downstream during less frequent floods (ie: 2
percent chance flood). But a structural fix would provide a predictable flow split
around Eagle Island with equal benefit to those who live both along the North and
South Channels during periods of more frequent floods (ie: 10 percent chance
flood). Multiple structural flow split proposals were considered as a part of a
Section 1135 study begun by the Walla Walla District USACE in 2002. They
include inflatable dam diversion works and diverting water through ponds at the
head of Eagle Island. To avoid design conflicts, this study has been placed on
hold pending the outcome of the design and environmental analysis of the
proposed Three Cities bridge crossing in that same area.
Another local proposal for flow split control is the Williamson Ranch
Proposal (Appendix F). This proposal includes using the established designated
FEMA floodway that departs from the South Channel at the Lemp Ditch diversion
structure. This proposal provides protection for the residents along the South
Channel from approximately 1 mile downstream Eagle Road up to the Lemp
Ditch. More than 1 mile downstream Eagle Road areas are subject to overland
flow as the flows shift from the North Channel to the South Channel. The
drawback to this plan is the assumption that every year is like 2006, and that the
desire is to get more flow from the South Channel to the North Channel. The
Williamson Ranch Proposal addresses this, but offers no solution in the years that
flows in excess of the traditional flow split are shifted to the North Channel. The
solutions proposed in the preceding paragraph would benefit residents along both
channels.
Long -Term Solutions with Long -Term Benefits for the Lower Boise River Valley
27
h. Construction of an additional flood storage dam in the Boise River Basin: This
alternative could provide flood control benefits, water supply and recreation. But
another dam would have to pass difficult environmental reviews, and would
destroy land based and riverine recreation within the dam impoundment area.
This idea may be a very difficult solution to implement.
i. Utilization of New York Canal as a multi-obiective irritation canal / flood control
works: The communities along the Boise River, in conjunction with the USACE,
USBR and the support of the irrigators could enlarge and rejuvenate the New
York Canal, such that it could provide greater flood water carrying capacity. This
would mean improving the outlet works on Lake Lowell as well to bypass flood
waters that would exceed their maximum pool. This proposal could benefit both
irrigators who would get a significant rehabilitation to their canal and flood
control reduction to the lower Boise River residents who live along the river.
This alternative would require the development of cost-sharing and operational
agreements that would allow for joint usage of that facility.
9. Conclusion
The Lower Boise River valley is going through considerable changes, both in the
changing river morphology and development within the floodplain. It is up to the
citizens of the Treasure Valley communities to develop a vision and come to terms with
the need to balance flooding concerns, development, and environmental preservation. If a
reasonable long term plan is not developed the river will eventually determine one of its
own, including accessing the entire floodplain.
The high water spring runoff in 2006 is a regular occurrence that happened to
follow six consecutive years of drought. Flows have exceeded 7,000 cfs at Glenwood
Bridge six times since 1982. That is an average of 1 in 4 years! The 2006 spring runoff
was not a major flood event. When the 1 percent chance flood occurs the floodplain will
first be accessed in the low lying areas flooded in 2006, then work its way in other
random locations, and finally work to inundate nearly the entire island.
The flow split at the head of Eagle Island is ever changing. While in recent
history flows between 2,000 cfs and 3,300 cfs have produced a flow split in the range of
36% to 47% of the flow in the South Channel, this year had a 50%-50% flow split. This
resulted in a 2 percent chance flood on portion of the South Channel upstream the
vicinity of the Eagle Road Bridge, while the main stem of the Boise River had a 10
percent chance flood. This indicates that the frequency of the flooding event on the North
and South Channels is independent from that on the main stem of the Boise River. This
flow split discussion is limited to the more frequent flows as the nearly all of Eagle
island, with the exception of the elevated structures, will be under some degree of water
during a 1 percent chance flood event. During the spring of 2006 there were no homes
flooded, even on the portion of the South Channel that saw a 2 percent chance flood
event.
The FEMA Maps are for less frequent high flow events than experienced in the
spring of 2006. A check to determine if the 2006 high flows (approximately a 10 percent
chance flood) could be contained within the 1 percent chance floodplain resulted in very
28
few small localized areas of error. Also shown on the aerial map overplots is that nearly
all the Eagle Island moderate risk areas, Zone X, have been completely constructed upon
in the Eagle Road area. The flow split that was determined for the FEMA mapping was
not what was observed in the spring of 2006. A designated floodway area needs to be
defined downstream Eagle Road and the designated floodway area near the Lemp Ditch
needs to be maintained. FEMA maps are developed with substantial attempts to make
them as accurate as possible, but they are only a snapshot in time. The maps offer no
assurance that areas flooded will not change as a result of erosion, deposition, movement
of bed materials, changes in split flow, development, or pit/lake/pond capture. The
FEMA maps also make simplifying assumptions that include no debris, bridge blockages,
scour, or sand bagging.
This paper identified near-term and long term, localized and valley -wide flood
prevention suggestions. Many of the ideas presented may be quickly dismissed if they do
not meet the goals and objectives of the Treasure Valley communities. The fact is that
there are no real good near-term solutions or quick fixes. Putting great expense into
localized fixes is usually not good economics. This is why the Lower Boise River Valley
needs to come together and develop a common vision, a vision of the future of the Boise
River. This vision can then be coupled with a plan to implement a lasting solution to
flooding concerns.
The high waters seen in the spring of 2006 were a picture of the beginning of the
1 percent chance flood. It is not a matter of "if' but "when" will the 1 percent chance
flood occur. Following the minimum guidelines FEMA outlines for construction in the 1
percent chance floodplain will leave hundreds of homes as individual islands when Eagle
Island inundates during the 1 percent chance flood. Now is the time for the City of Eagle
and the entire Treasure Valley to take action before "The Big One" hits. Thank you for
the opportunity to prepare this report.
10. References
Corps of Engineers. 2001. Engineer Pamphlet (EP) 500-1-1. Civil Emergency
Management Program. September.
Corps of Engineers. 1985 (with revisions). Water Control Manual for the Boise River
Reservoirs. Walla Walla District. April.
Federal Emergency Management Agency. 2003. Flood Insurance Study, Ada County,
Idaho and Incorporated Areas. Community No. 16001CV000A. February.
Towill, Inc. 1998 Topographic Maps, Scale 1:700, Contour Interval 2 feet. December.
29
DIS IN 1000 CUBIC FEET PER SECOND
1
DATE 11/21/2003 TIME 16:17:55
US ARMY ENGINEER DISTRICT, WALLA WALLA
ENGINEERING DIVISION, HYDROLOGY BRANCH
HYDROLOGIC DATA (DISCHARGE IN 1000 CUBIC FEET PER SECOND)
30 30
20
15
10
5
,: /..3:,,7
20
15
10
5
0
OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP
BOISE RIVER AT LUCKY PEAK DAM. IO - UNREGULATED INFLOW
1983
F' BOISE RIVER AT GLENW00D BRIDGE - TOTAL DAILY DISCHARGE 1983
OISCHARI{ IN 1000 CUBIC FEE1 PER SECOM)
1
N
20
15
10
5
DATE 11/21/2003 TIME 16: 18: 37
US ARMY ENGINEER DISTRICT, WALLA WALLA
ENGINEERING DIVISION, HYDROLOGY BRANCH
HYDROLOGIC DATA (DISCHARGE IN 1000 CUBIC FEET PER SECOND)
OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP
BOISE RIVER AT LUCKY PEAK DAM. ID - UNREGULATED INFLOW
BOISE RIVER AT GLENWOOD BRIDGE - TOTAL DAILY DISCHARGE
1997
1997
US ARMY ENGINEER Di STRICT, WALLA WALLA
ENOINEERING DMSION, HYDROLOGY BRANCH
HYCIROLOO1C DATA (DISCHARGE Its 1000 CUBIC FEET PER SECOND)
OCT NOV DEC JAN FEB MAR
•
•
-APR MAY JUN JUL Pkt I1 SEP
&CASE F*vEF. AT LUCKY PEA$ DAM, ICG - Ut EGL�R iECI INFLe P U►7h -4
BC43E FIVER AT (LEN.v►".),XI BFI'( - TOTAL DALY DiSCHAR� E 2006
10
I -i
DATE 11/21/2003 TIME 16:19:32
US ARMY ENGINEER DISTRICT. WALLA WALLA
ENGINEERING DIVISION. HYDROLOGY BRANCH
HYDROLOGIC OAIA (DISCHARGE IN 1000 CUBIC FEET PER SECOND)
30 -
130
25; - 125
-t
OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP
BOISE RIVER AT LUCKY PEA,: DAH. 10 - uNPEGuLAIED INFLOW
BOISE RIVER AT GLEhx000 BRIDGE - TOTAL DAILY DISCHARGE
1980
1980
20
15
10
C! AM 1ti 1C O DE: 1{E' SEP 1CK
30
25
I
20 --
15
10
DATE 11/21/2003 TIME 16:20:49
US ARMY ENGINEER DISTRICT, WALLA WALLA
ENGINEERING DIVISION. HYDROLOGY BRANCH
HYDROLOGIC DATA (DISCHARGE IN 1000 CUBIC FEET PER SECOND)
--
t-
OCT NOV DEC JAN FEB MAR APR MAY JUN JUL
BOISE RIVER AT LUCKY PEAK DAM. ID - UNREGULATED INLDw
BOISE RIVER AT GLENwOOD BRIDGE - TOTAL DAILY DISCHARGE
1993
1993
AUG SEP
30
25
20
15
10
5
DATE 11/21/2003 TIME 16: 21: 16
US ARMY ENGINEER DISTRICT, WALLA WALLA
ENGINEERING DIVISION, HYDROLOGY BRANCH
HYDROLOGIC DATA (DISCHARGE IN 1000 CUBIC FEET PER SECOND)
30 : 30
25 - --•
25
z;-1 20 20
ref
10
5 -
OCT NOV DEC JAN FED MAR APR MAY JUN
BOISE RIVER AT LLCK'r PEAK DAM. ID - (RuPEWLATED INFLOW
BOISE RIVER Ai G:F.NADOO (BRIDGE - TOTAL DAILY DISCHARGE
i 10
0
JUL AUG SEP
1998 --±-
1998
DATE 11/21/2003 TIME 16:22:57
US ARMY ENGINEER DISTRICT, WALLA WALLA
ENGINEERING DIVISION, HYDROLOGY BRANCH
HYDROLOGIC DATA (DISCHARGE IN 1000 CUBIC FEE1 PER SECOND)
30 ---- - 30
25 ----
25
20
15
10
5 5
0 -- - --- t 0
OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP
BOISE RIVER AT LUCKY PEAK OAH, 10 - UNREGULATED INFLOW
80ISE RIVER AT GLENW000 BRIDGE - TOTAL DAILY DISCHARGE
1992
1992
IN 1000 CUBIC FEET PEA ICH
DATE 11/21/2003 TIME 16:23:48
US ARMY ENGINEER DISTRICT, WALLA WALLA
ENGINEERING DIVISION, HYDROLOGY BRANCH
HYDROLOGIC DATA (DISCHARGE IN 1000 CUBIC FEET PER SECOND)
30 30
25 25
20 20
15 15
10 10
5
1 �
1
r � 1
OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP
BOISE RIVER AT LUCKY PEAK DAM, ID - UNREGULATED INFLOW 2000
co BOISE RIVER AT GLENW00D BRIDGE - TOTAL DAILY DISCHARGE 2000
5
0
DISC S IN 1000 OE FEE1 PER ICH
m
DATE 11/21/2003 TIME 16:24:09
US ARMY ENGINEER DISTRICT, WALLA WALLA
ENGINEERING DIVISION, HYDROLOGY BRANCH
HYDROLOGIC OATA (DISCHARGE IN 1000 CUBIC FEET PER SECOND)
30 30
25 25
20 20
15 15
10
5
0
OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP
BOISE RIVER AT LUCKY PEAK DAM, ID - UNREGULATED INFLOW
BOISE RIVER AT GLENWOOD BRIDGE - TOTAL DAILY DISCHARGE
2001
2001
10
5
0
30
25 1
:n 20
15
10
9.
0
DATE 11/21/2003 TIME 16:24:57
US ARMY ENGINEER DISTRICT, WALLA WALLA
ENGINEERING DIVISION. HYDROLOGY BRANCH
HYDROLOGIC DATA (DISCHARGE IN 1000 CUBIC FEET PER SECOND)
30
-1 25
20
-1 15
OCT NOV DEC JAN FEB MAR APR
MAY
BOISE RIvER AI LUCKY PEAK DAM, 10 - U MEGuLAIED INFLOK
BOISE RIVER AI GLENWOOD BRIDGE - IOTAL DAILY DISCHARGE
JUN
JUL
AUG
SEP
2002
2002
N:,FK 6
FoR' BOISE a%
EAGLE
801SE, RIYER•BAS14
:BELOW LUCKY 1PEAK DAM:
SNAKE
RIVE'
NOTES:
ARROWROCK
DAM
-BOISE• RIVER ,BASIN
ABOVE LUCKY PEAKDAM
BO)SE-
DLUCKY PEAK
AM
1. BASE MAP IS U.S.G.S. GEOREFERENCED 1:250.000 OUADRANGLES
"BOISE. ID.. 1955 (REVISED 1976)". "HAILEY. ID.. 1955
(REVISED 1970)" AND "CHALLIS. ID.. 1989".
2. THE BASIN AREAS WERE DIGITIZED FROM THE "BOISE RIVER BASIN
FEATURES MAP". CONTAINED IN THE U.S.A.C.E. PUBLICATION "LOWER
BOISE RIVER AND TRIBUTARIES. RECONNAISSANCE STUDY. 1995".
APPENDIX B. PLATE 1.
50000 _ 50000
SCALE IN FEET
}S. FK BOISE RIVER
ANDERSO
ANCH D
i 0
tf
t GJ
NOTES:
1. CROSS SECTION LOCATIONS AND THE 1% ANNUAL CHANCE FLOODPLAIN DELINEATION
IS DIGITIZED FROM THE F.E.M.A. FIRM MAPS 16001C0134 H. 16001C0130 H. 16001C0135H.
16001C0140 H. 16001C0141 H. 16001C0142 H. 16001C0130 H AND 16001C0140 H. ALL DATED
FEBRUARY 19. 2003.
2. ZONE X AREAS ON THIS MAP ARE AREAS OF 17. ANNUAL CHANCE FLOOD WITH AVERAGE
DEPTHS OF LESS THAN ONE FOOT OR WITH DRAINAGE AREAS LESS THAN ONE SQUARE
MILE: ANO AREAS PROTECTED BY LEVEES FROM THE 1% ANNUAL CHANCE FLOOD.
3. AERIAL PHOTOGRAPHY FLOWN 11 MAY 2006 AT A HIGH FLOW RATE. THE PHOTOS WERE
UNCONTROLLED AND APPROXIMATE ON THE MAP. THE PHOTOS WERE SCANNED AND
DIGITIZED TO A DIGITAL ORTHO PHOTO THAT WAS PROJECTED TO THE STATE PLANE DATUM.
4. THE 17. ANNUAL CHANCE FLOODPLAIN IS 16.600 C.F.S.
ra.141
i 114
j efr4� s
1
L
r'\
a
1
CH)
LEGEND
FIRM 1% CHANCE EXCEEDENCE FLOODPLAIN
'--e FIRM CROSS SECTION LOCATION
(P) )
2000 9
2000
SCALE IN FEET
3R a.r
r • d.
•
ASS -
y
a
0
0
w
z
J
MATCH LINE MAP 2
US N,'m Corp.
.w or4 Ow.
tv
CITY OF
¶#J EAGLE
if 6:44% r. 2;..
NOTES:
1. CROSS SECTION LOCATIONS AND THE 17 ANNUAL CHANCE FLOODPLAIN
DELINEATION IS DIGITIZED FROM THE F.E.M.A. FIRM MAPS 16001C0130 H.
16001C0134 H. 16001C0135 H. 16001C0140 H. 16001C0141 H AND
16001C0142 H. ALL DATED FEBRUARY 19. 2003.
2. ZONE X AREAS ON THIS MAP ARE AREAS OF 17. ANNUAL CHANCE FLOOD
WITH AVERAGE DEPTHS OF LESS THAN ONE FOOT OR WITH DRAINAGE AREAS
LESS THAN ONE SQUARE MILE; AND AREAS PROTECTED BY LEVEES FROM THE
1% ANNUAL CHANCE FL000.
3. AERIAL PHOTOGRAPHY FLOWN 11 MAY 2006 AT A HIGH FLOW RATE. THE
PHOTOS WERE UNCONTROLLED AND APPROXIMATE ON THE MAP. THE PHOTOS
WERE SCANNED AND DIGITIZED TO A DIGITAL ORTHO PHOTO THAT WAS
PROJECTED TO THE STATE PLANE DATUM.
4. THE 17. ANNUAL CHANCE FLOODPLAIN IS 16.600 C.F.S.
cl r:
i:.
•
.
'fila+;_ . ��•..
LEGEND
FIRM 17. CHANCE EXCEEDENCE FLOODPLAIN
f1j FIRM CROSS SECTION LOCATION
2000 9 2000
SCALE IN FEET
APPENDIX A
Official Correspondence
July 18, 2006
Lieutenant Colonel Anthony J. Hofmann
Commander, Walla Walla District
U.S. Army Corps of Engineers
201 North Third Avenue
Walla Walla, Washington 99362-1876
Dear Lieutenant Colonel Hofmann,
Thank you so much for the Corps efforts on behalf of the City of Eagle regarding the
high water events that occurred this spring. I appreciate the Corps expertise and
willingness to advise us and to simply be there when we needed you. As we all know,
there is some discrepancy between the maps and what is actually happening on the Boise
River.
I believe we do need to take precautionary steps this year before the next high water
season to mitigate some of the issues that arose this year regarding bank breaching. The
Corps have a good history of past events and are also able to look at the broader picture
when it comes to what needs to happen, as well as, what can be done to mitigate future
problems.
I am especially concerned about the capacity of the bridges and their ability to really
allow flood waters to flow under the bridges at Eagle and Linder roads. As you know,
the high water in both of the channels of the Boise River has created a great deal of
concern for many of our citizens. I am hopeful that you might help us come to some
solutions before the next water year.
I would greatly appreciate if we could look to you for further counsel and advise as we
try to help correct the problems that have occurred along the Boise River this past year.
Sincerely,
Nancy C. Merrill
Mayor
cc: Eagle City Council
1
Members
Matt Beebe
Canyon Corny
Commiss.oner
Davo Dieter
Mayor. Borsa
Tom Dao
Mayor. Nampa
Tammy do Weerd
Mayor, Medd.an
John Evans
Mayor, Garden Coy
Frank McKeever
Mayor, t.Uddieton
Nancy Morrill
Mayor, Eagle
Nato Mitciwll
Maya, Slat
Garret HancoIas
Maya, Ca►iwea
Dean obray
Mayor, Kuna
Margie Watson
Mayor, Parma
Rick Yzaguirrs
Ada County
Conn ssroner
PO Box 1124 Meridian, ID 83680-1124
208-761-6395 Fax 208-846-9394
WWW.trrasurevaIlev artners ore
September 29, 2006
Chairman Jerry Rigby
Idaho Water Resources Board
553 E. Ott' South
Rexburg, ldaho S3440
Dear Chairman Jerry Rigby
'Phis past spring Treasure Valley citizens witnessed the !tighcit flows along
the Boise River in a decade. While this )Tat'}: event was not urlumial. It is
obvious to the frcasure Valley leadership that communities have a cntica! need
for better floodplain planning and management.
We, the members of the Treasure Valley Partnership, know that the Boise
River represents the very essence tor human life. providing water for farmlands
and other industry, drinking v.:der for our citizens. floodpluins, diverse
recreational opportunities, and important ecological systems.
We also recognize that flooding along the Boise !rives bar been and will
continue to he a major pan of the natural pi rrccss. Developing a plan for the
Boise River is crucial so that we ean strike a sustainable balance between flood
damage -reduction measures and other equally important uses of the natural and
water resources provided by the Boise River.
After this year's high water events, we sec a greater need to protect and
enhance our local tloodplains. We also need to reduce future flood impacts to
our local economy, protect the long-term health, safety and welfare ofour
citizens, and protect the health of our environment.
We have solicited help and expertise from all sectors of the Federal, State and
County governments as well as Boise River Flood Control Districts 410 and 11.
We arc undertaking a major Treasure Valley wide floodplain ordinance
review/revision process in an effort to make our collective ordinances seamlessly
compatible.
On a broader front, State Representatives Jana Kemp and Rill F)cal have
joined us in this effort, funning a task force that has identified additional regional
and state-wide floodplain planning, preparedness challenges and oppornmities to
be examined.
2
Idaho Water Resources Board
September 29, 2006
Page 2
The U.S. Army Corps of Engineers Walla Walla District, the Idaho
Department of Water Resources, and the Idaho Bureau of Homeland Security
have provided invaluable help and advice this year both during the high water
events and after. We understand that the Corps was given special Congressional
Authority in the Water Resource Development Act of 1999 (WRDA 99), Section
414, to partner with our State and local governments to identify alternatives and
study ways to reduce the impacts of flood events, while also examining water
quality issues, recreational opportunities, and other watershed improvements.
Further, we understand that the Energy and Water Development Act, 2007 as
reported in the U.S. Senate proposes to appropriate $.130,000 of fcdcral funding
to support this effort.
WRDA 2006 is currently before Congress and has proposed language that
could give the State of Idaho significant credit for study work already performed
by the Idaho I)cpartment of Water Resources as well as other non-fcdcral
agencies. If WRDA passes with this credit language, it would give the Treasure
Valley a significant opportunity to plan a better and healthier iiuure liar bower
Boise River.
We vrrould ask that you direct your Water Resource Board staff to meet with
the Treasure Valley Partnership to discuss the likelihood and potential of the
Idaho Department of Water Resources sponsoring such a study in collaboration
with the members of the Treasure Valley Partnership, Flood Control Districts 10
and 11, and the Corps of Engineers.
Sincerely,
lei 7./ /ry-,f•s elf -d-4(
Nancy C. 'Merrill
I114yor of Eagle
President of Treasure Valley Partnership
cc: Eagle City Council
Treasure Valley Partnership
3
Members
Matt Beebe
Canyon County
Con-nissioner
Dave Bleier
Mayor, tiNse
Tom Date
tAayor, Nampa
Tammy de Wooed
Mayor. iicrduen
John Evans
Mayor. Garden City
Frank McKeever
Mayor, kkddleton
Nancy Morrill
Mayor. Eagle
Nate Mitchell
Kayor, Stu
Garret Nancotas
Mayor, Celd ve l
Dean Obray
Mayor, Kona
Margie Watson
Mayor. Parma
Rick Yzaguirro
Ada Co.rrty
Co•iriss.oner
PO Box 1124 Meridian, ID 83680-1124
208-761-6395 Fax 208-846-9394
www. treasurevalleypartners ory
October 4, 2006
Congressman Butch Otter
1711 Longworth
Washington, DC 20510
Dear Congressman ngresstnan Otter,
This past spring we saw the highest flows along the Boise Rivet since the late
1990's flow through our Treasure Valley, We, the rncmfxrs of the •1 rcisure
Valley Partnership (a consortium of Mayors) know that the Boise River
represents the very essence for human Life providing water for fannhutds and
other industry, drinking water for our citizens, foodplains, di arse recreation
opportunities, and important ecological systems.
Our citizens and goverrunent officials also recogni�.ed that flooding along the
Boise River has been and will continue to be a major part of the natural process
that we must plan for. Developing a plan is crucial so that we can strike a
sustainable balance between flood risk reduction measures and other equally
important uses of the natural and water resources that the Boise River provides.
The scusible and sustainable development of water resources is a tr.rp priority in
our Treasure Valley. A key partner in this effort is the ITS. Artily Corps of
Engineers. We rely on the Corps for the traditional flood risk reduction work
they do by operating Lucky Peak Dam and Reservoir. I lowever, we also see
them as a tremendous resource for pluming and engineering assistance. The new
direction of the Corps, to be more customer focused, is heartening to those of us
who have worked side•hy-side with the Corps as they provided invaluable help
and advice both during this year's high water events and after,
I understand that the Corps was given special Congressional Authority in the
Water Resource Development Act of 1999 (WRDA 99), Section 414, to partner
with our State and local governments to identify altemativcs and study ways to
reduce the impacts of flood events while also examining ecosystem and riparian
restoration, water quality improvements, and recreational opportunities. Further
we understand that the Energy and Water Development Act 2007, as reported in
the U.S. Senate, proposes to appropriate $330,000 of federal funding to support
this effort.
4
Congressman Butch Otter
October 4, 2006
Page 2
WRDA 2006 is currently before Congress and has proposed language that could
give the State of Idaho significant credit for study work already performed by the
Idaho Department of Water Resources as well as other non-federal agencies. If
WRDA passes with the credit language, it would give the Treasure Valley a
significant opportunity to plan a better and healthier future for Lower Boise
River and all the uses this resource provides.
Congress has an excellent opportunity with WRDA and the FY07 Appropriations
Bill to support innovative solutions that support the Corps cif Engineers efforts to
improve and expand their needed services to local governments. On behalf of
the citizens of the City of Eagle and the Treasure Valley Partnership, I encourage
you to look favorably on this important legislation.
Sincerely,
Npncy C. Merrill
I.
Mayor of Eagle
President of Treasure Valley Partnership
cc: U.S. Senator Larry Craig
U.S. Senator Mike Crapo
Congressman Mike Simpson
Karl Dreher, Director, Idaho Department of Water Resources
Lt. Col. Anthony 3. Hofmann, Commander, Walla Walla District, USAGE
State Representative Jana Kemp
State Representative WW Deal
Bill Clayson, Chairman, flood Control District 10
R. Jarrell Glenn, Chairman, Flood Control District 11
Treasure Va11cy Partnership
Eagle City Council
5
Members
Matt Beebe
Canyon County
Commissioner
Dave Bietor
Mayor, Bose
Tom Dal*
Mayor, Nampa
Tammy de Woerd
Mayor, Meridian
John Evans
Mayor, Gsrden City
Frank McKeever
Mayor, M dloton
Nancy Merrill
Mayor, Eagle
Nate Mitchell
Mayor, Star
Garret Nancolas
Mayor. Caldwell
Dean ()bray
Mayor, Kuria
Margie Watson
Maya, Parma
Rick Yaguirre
Ada County
Commeclaner
PO Box 1124 Meridian. ID 83680-1124
208-761-6395 Fax 208-846-9394
wu tvS,-r-asurcvellevp rtrrera art,
October 4, 2006
Lieutenant Colonel Anthony J. 1-ioiimutn
Commander, Walla Walla District
U.S. Army Corps of Engineers
201 North Third Avenue
Walla Walla, Washington 99362-1876
76
Dear Lieutenant Colonel Hofmann,
As follow-up to our earlier meeting in August, I wanted to give you a quick
update of our tloodplain planning actions and activities presently ongoing in the
Treasure Valley.
As 1 have expressed to you and your stall. we rely on the Corps for the traditional
flood risk reduction you do by operating Lucky Peak Darn and Reservoir. We
also see your organization as a tremendous planning and engineering resource.
Jite Treasure Valley Partnership a consortium of \11:1•ors has solicited help and
expertise from all sectors of the Federal, State and County gmernmcnts as well
as Floud Control District 10. We are undertaking n Inikint'i•reasure Valley wide
floodplain ordinance reviewr'revision process in an effort to make our collective
ordinances seamlessly compatible.
On a broader front, State Representatives .lana Kemp and Bill Deal have joined
us in this effort and have firmed an additional task force that has identified
additional regional and state-wide floodplain planning and preparedness
challenges and opportunities to he examined. We deeply appreciate the timely
advice, counsel and technical input on both of these efforts provided by
Brayton Willis of your Boise Office. 1 also understand that you are developing
an after action report as a result of this year's high water event. We look forward
to seeing the results of that effort.
6
Lieutenant Colonel Anthony J. Hofmann
October 4, 2006
Page 2
The communities and local homeowners associations have expressed much
interest in having a "levee" workshop here in the Boise area. I have discussed
that thought with Mr. Willis and he suggested that a one day event partnering
with the Idaho Department of Water Resources, University 01 Idaho, City and
County officials, Flood Control Districts 10 and 11, and the Walla Walla District
would certainly be worth considering and planning for in the near future. With
the vast number of existing "levees" and berms that are considered unsatisfactory
along the entire reach of the Lower Boise River, it would be invaluable to the
local community to better understand what we can do to develop sustainable
solutions for flood risk reduction on our hanks.
Thank you very much for all that you and your staff do for our community and
our county. 1 look forward to your next visit to our arca
. Sincerely,
/
Na'tcy C. errill '
Mayor of Eagle
President of Treasure Valley Partnership
cc: Eagle City Council
Treasure Valley Partnership
7
on
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0
0
b
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o0
Wa
0.4
on
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N
APPENDIX C
Boise Project Office Response
USACE Ef,;ise Project Otf.L Sl1rh '1 -1/14!)/JC ,
L'CIsi-(_):Tt"c tt;c ' _.-
ERSC ct Eacle Ild t-:l7A1 inif:1 jL::t (:
i i J I
,•;'.:c�..'c.�:_:
Discharge. cubic feet per second
`.lost recent.ahle . 930 ,..,;•14•2Z15 i 1 29
•
1 3666
2888
1
USCG 13206903 00ISE RIVER ODUTN CI1RWIEL 6T EAGLE I0
Ir,' e•:e::.1I
Apr 07 Apr 00 Apr 09 Apr 10 Apr 11 Apr 12 Apr 13 Apr 14
EXPLANATION
DISCIIARGE
NEOIAN OAILY STREONELOU BASED ON G YEARS Or RECORD
Scc.,tt Jan Hoff. "[hey (vnT1r11iG :I ; se
the south s,de of the oliennal 111€4 u"6'gen tif: ok:ktC1 'lit
T^ c sub-dlvis cn '' Lirrti-I"!'1
grading and devei'.pment at !n ] tlitn
WiroJxoYi tnai.III I .248.+ 84. 5$9
Arloteir Co Mens
Zo, Ai.n44.<1 r l /164,41
4:\ it. AA.
pyro.s aN
rte.: "' 1
•
About an hours after the initial breach. Laguna' Lake cvcrtopped and flood flews micr:_ited to a
five-foot drain passing under Eagle Road [route 55. a major N -S highway), Debris blocked the
drain and began to back up at the highway Developer's construction crows mobilized a backhoe
to clear the debris from the drain before overtopping the road
1
rhino f!. .. .
reported
The developer i.nnso
lave The lake :s 26-28 fFi t
charnel flo'.v ',%as captured n
at the top end of the lake
The breach was reported to be int S.hra
Upstream and on the oppc'•otrt sii'}M
recently placed sand tag.,
Regulatory office advised the Y,7
drain 'l, y'J _!,dar.`_yq
f!tU tri` :d,'hl Slf aril osn': of t.ae
l.�00 tt;ia .:Cfll-05 i.)t
5 _. wr,C ,. g k... .vzyrc5 ;L6 r v r
I tJev ral nays 3(30, BoISe
:t;,
At 140) today. Regulatory feport " t c.' to cfb ha:a now drvsrtcd into the pond
The developer '1A/Iii attempt to doe ti, : ry roar future'.
While :he locals handled the situation :ve, . !' .,! :ty is very, very lucky Had this preach
occurred late in evening/early morning, the I : c;f Eagle Highway and the subsequent
flooding of the downstream subdivision coo'. astrr,p uc cctnseguences
2
APPENDIX D
Permits
Post -flooding repairs may require permits
News Release 06-30 Date: May 02, 2006
Public Affairs Office, Walla Walla District Headquarters, U.S. Army Corps of Engineers, 201 N. Third Ave, Walla Walla,
WA 99362-1876
Phone (509) 527-7020 FAX (509) 527-7824
WALLA WALLA, Wash. — Heavy rainfall during April led to increased flows and some
minor flooding along several rivers in southern Idaho. People who want to do in -water work for
flood protection or to repair damage following flooding should first check with state and federal
officials to see if they need a permit for the work they want to do, advise regulatory officials from
the U.S. Army Corps of Engineers.
The Walla Walla District of the U.S. Army Corps of Engineers administers the
Regulatory Program in the State of Idaho under Section 404 of the Clean Water Act and Section
10 of the Rivers and Harbors Act of 1899. Under these laws, a permit is required for most
construction activities in waterways and wetlands. These include lakes and ponds, as well as
intermittent and perennial rivers, streams, and creeks.
"During flood emergencies, we do all we can to streamline permit coordination with
other federal, state and local agencies, and the public," noted Brad Daly, Walla Walla District's
Regulatory Division chief. "Some limited repair and maintenance activities do not require a
permit."
The District's Regulatory Division has eight project managers located in field offices in
Coeur d'Alene, Boise and Idaho Falls, as well as the District headquarters in Walla Walla.
The following, bulleted information describes permit requirements for common flood
protection and repair work in Idaho. Regulatory staff members are also available to answer
questions on specific projects not mentioned below. In some cases, a regulatory specialist may be
available to meet on-site to inspect problems and discuss permit requirements.
• A Corps permit is required for placing dredged (excavated) or fill material below the ordinary
high water mark of a waterway or in wetlands. A Corps permit is also required for bulldozing
gravel or other material below the ordinary high water mark or in wetlands.
• The Corps does not need to be contacted for work conducted above the ordinary high water
mark and outside of wetland areas. A Corps permit is not required to place sandbags in uplands
around a house or other structure that is threatened by floodwater, or to construct dikes or levees
above the ordinary high water mark and outside of wetland areas.
• Permits are not required when front-end loaders, or similar bucket -type equipment, are used for
emergency removal of gravel, fallen trees and other minor debris that may cause bank erosion or
flooding. In general, debris should not be disposed in the waterway, high flow channels or
wetlands. Removal activities conducted with a bulldozer or removal of large gravel and debris
piles, however, require a permit and should be coordinated with Corps regulatory staff. Wholesale
channel clearing, cleaning and relocation most likely require an individual permit application and
is discouraged. In addition, high flow channels and wetlands, which can carry or store
floodwaters, should not be blocked off. All material removed must be disposed of in an upland
location and not disposed in waterways or wetlands.
• Certain types of work are exempt from permit requirements unless located in navigable waters.
Among these are repair of existing dikes, dams, levees, riprapped banks, breakwaters, causeways,
bridge abutments and roadways damaged by recent flooding, if there is no change from the
original design.
1
• In addition to the exempt activities listed above, there are several nationwide permits that
authorize minor activities in waterways. Nationwide Permit -13 authorizes bank protection
projects such as placing rock riprap along a riverbank or shoreline. To qualify for this nationwide
permit, the rock must be placed at the point of erosion. Nationwide Permit -3 authorizes the
excavation of gravel and debris in the immediate vicinity (not further than 200 feet) of bridges,
culverts or other structures to restore the waterway to the approximate dimensions that existed
when the structure was built. The excavated material must be disposed of in a location where it
cannot reenter the waterway.
Proposed projects are not authorized in areas where federally listed, endangered or
threatened species live until consultation is completed with the U.S. Fish and Wildlife Service or
the National Marine Fisheries Service. In emergency situations however, this may be expedited
by using emergency consultation procedures. In addition, there may be regional and water quality
certification conditions that may apply. Because of this, it is recommended people contact Corps
and state regulatory officials for permit requirements relating to their specific situation.
"Often, questions may be answered over the telephone with little or no paperwork," said
Daly. "We make every effort to expedite required permits."
A free information packet that explains permit requirements, and an application form is
available on the District's Web site, www.nww.usace.army.mil/html/ofces/op/rf/rfhome.htm.
For more information or to request this packet, contact the Corps regulatory office nearest you:
Idaho Department of Water Resources (IDWR) may also require a permit for work below
the ordinary high water mark of perennial streams and rivers. The Corps and IDWR cooperate to
expedite permit applications for all flood work.
2
APPENDIX E
Local ordinances
6/20/2006 Flooding Ordinances
Analysis of Components
Ma Canyon Garden
Components County County Boise Caldwell Eagle City Kuna Meridian Middleton Nampa Star
Purpose (same) X 2 X 1 X 1 X 1 X 1 X 1 X 1 X 1 X 1
Methods of Reducing Loss (same) X 3 X 2 X 2 X 2 X 2 X 2 X 2 X 2 X 2
Flood Hazard Areas
Flood Ins Study for Caldwell, Sept. 30, 1988 X 5
Flood Ins Study for Ada, Sept 22, 1999 X 7
Flood Ins Study for Ada, Feb. 19, 2002 X 6
Flood Ins Study for Ada, Feb. 19, 2003 X 8 X 5 X 5
Flood Ins Study for Middleton, Dec. 3, 1993 X 5
Flood Ins Study for Kuna, October, 2003 X 6
Penalties for Non Compliance $ & time $ & time $ & time $ & time $ & time $ & time
Disclaimer of Liability X 3 X 2 X 8 X 6 X 15 X 7 X 6 X 18 X 6 X 20
Administrative Process Requirements
Requirements for Permit X 3 X 6 X 5 X 6 X 5 X 6 X 7
Designation of Administrator X 1 X 2 X 8 X 6 X 11 X 8 X 7 X 6 X 6 X 6 X 8/16
Alteration of Watercourses X 7 X 2 X 9 X 8 X 7 X 14 X 7 X 16
Appeals X25 X8 X6 X6 X 12 X8 X7 X8 X8
Flood Hazard Standards pg. 13 - 19 pg. 10 - 13 pg. 6 -11 pg. 9 - 13 pg. 8 - 12 pg. 8 - 12 pg. 7 - 13 pg. 10 - 13 pg. 9 - 15
Anchoring X X X X X X X X X X X
AH Zone Drainage X
Materials and Methods X X X X X X X X X X X
Utilities X X X X X X X X X X X
Residential Construction
Lowest floor above base flood X X X X
Lowest floor 1' above base flood X X X
Lowest floor 2' above base flood X X X X
Enclosed areas below lowest floor
min 2 openings 1 inch per foot X X X X X X X X X X X
bottom of openings 1 foot above grade X X X X X X X X X X X
openings equipped with screens X X X X X X X X X X X
lowest floor area elevated > 12 inches X
1
Ma Canyon Garden
Components County County Boise Caldwell Eagle City Kuna Meridian Middleton Nampa Star
Nonresidential Construction
Lowest floor above base flood X X X X X X
Lowest floor l' above base flood X X X
Lowest floor 2' above base flood X X
walls impermeable below flood level X X X X X X X X X X X
components resist hydrostatic/hydrodyna X X X X X X X X X X X
Manufactured Homes X X X 17 X X X X X X X X
Recreational Vehicles X X 19 X X
Fill Requirements X 10 X 12 X 14
Variance Procedures X 25 X 8 X 8 X 8 X 12 X 12 X 7 X 15 X 8 X 17
Undesignated Regluatory Floodway X 13
Flood Way Provisions
Encroachments X 7 X 13 X 9 X 13 X 15 X 14 X 10 X 13 X 12
Minimum setback of 50' from floodway line X 9 X 10 X 12
Compensating excavation of floodway X 10 X 13
Shallow Flooding Area Standards
New Construction X X 14 X 15
Drainage paths around structures X 14 X 16
Recreational Vehicles X 14 X 16
Critical Facilities X 20 X 14 X 16
#'s next to X indicates the page this can be found on.
2
HEAD OF EAGLE ISLAND
PROPOSED FLOODWAY MODIFICATION
During the spring runoff in 2006, the South Channel of the Boise River experienced
higher flows than were generally anticipated. One apparent cause of the higher flows
was the inability for excess flows in the South Channel to access the regulatory
floodway connecting to the North Channel. The purpose of this write-up is to propose a
potential solution to the problem.
Problem Statement
When the Boise River had highwater discharges in 2006, property owners on Eagle
Island along the South Channel experienced near -100 -year flows. At the same time,
the North Channel ran at significantly lower levels. Apparently, an unmanaged flow
distribution at the head of the Island is a significant contributor to the problem faced by
residents along the South Channel.
Properties along the South Channel that were threatened by higher than anticipated
water during the 2006 runoff season included River's End, Island Woods, Laguna Point,
and the Cottonwoods.
Below the head of Eagle Island, a regulatory floodway is designated to allow excess
flow in the South Channel to convey to the North Channel. Where this floodway leaves
the South Channel, the diversion structure for the Lemp Ditch serving the Williamson
Ranch on Eagle Island is also in the same location. The conflict between the two uses
essentially guarantees that the linking floodway will only be activated once the river
rises to the level that a breach occurs in the river bank near the diversion structure.
Proposed Solution
Allowing the flows in the South Channel to utilize the linking floodway prior to a major
breach will minimize damages to the Lemp Ditch diversion, to downstream properties
adjacent to the South Channel, and possibly to residents on Eagle Island above Eagle
Road.
The most significant impediment to allowing the South Channel flows to access the
linking floodway is the existence of the banks along the Lemp Ditch. If the Lemp Ditch
were piped for a short run (200 - 400 feet) and the banks removed above the pipe, high
water from the South Channel could be routed overland, through the Idaho Concrete
ponds (the designated linking floodway) and into the North Channel. This routing would
relieve pressure on the downstream residents along the South Channel. At the same
time, sufficient conveyance capacity exists in the North Channel to provide a safe
conveyance of the anticipated additional flows.
In order to make such a river management option possible, permission to pipe the ditch
will need to be obtained from the Williamson family. Once permission is obtained, a
detailed hydraulic study will need to be accomplished to identify design parameters for a
successful project.
Head of E i 0e llsland
FIoodwa s
�`"���' •
IDAHO
COIRETE
600 300
0
600
1.200 Feet
111
■■ (,)1.1 ,11 1111
Head of Eagle Island
Floodways
A.
RELOCATE FLOODWAY TO HERE & AWAY FROM DIVERSION
qf
PIPE LEMP DITCH TO ALLOW FLOODWAY CONNECT SOUTH AND NORTH CHANNELS
200
100
200
'"... +..
400 Feet
•_ —