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PURPOSE & AGENDA "'"
U.S.ARMY
Provide update to City of Seward on progress of Pre-Construction, Engineering & Design phase
of Lowell Creek Flood Diversion project.
• Team Organization
• USACE Change Control Board (CCB) Update
• Project Design Maturity
• Current Design of Inlet, Tunnel and Outfall Features
• Design & Construction Schedule
• Q&A
3
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USACE ENTERPRISE ESIGN APPROACH
U.S.ARMY
Specialized Team hand selected across the count for theirs ecialties
country p
Engineering Lead,
C-- Contracting, Cost Eng
Alaska District (POA) and Project Management
Project Delivery Team
I N
Inlet& Outfall Design
ARMY CORPS OF ENGINEERS
USACE I
Team also engaging experts
Omaha District(NWO) i
EnterprisenvolvedinMudMtnand
Pfaffens run tunnels
Dam Safety Production p
Team y
Center
USBR Hydraulics Lab
RM
.R45K.MANAGEMENT CENTER
7Anjalyzte I Assess i Manage 1 Reduce
W L t s
Tunneling Design
Risk Management
Center(RMC)
4
CHANGE CONTROL BOARD (CC ) UP ATE CI®R
U.S.ARMY
• USACE policy requires a certified cost estimate every 2 years
• Feasibility level cost estimate April 2021
• 35% Design Milestone March 2023
Value Engineering Study April 2023
• Design Progression
• Pencils down September 2023
• Cost Schedule Risk Analysis Meeting October 2023
• New certified Cost December 2023 — triggered CCB
CCB meetings
• 11 Dec
• 19 Dec
• 12 Jan
• 24 Jan — Revised CSRA file, updated contingency
• Rescheduled to 21 Feb HQ USACE Brief
r•d
5
ESIGN MATURITY
CI®R
U.S.ARMY
Design Agreement June 2022; Design Charette Oct 2022
Project is currently at 45% design maturity, and project performance
PED Completed
• Phase I Geotech Investigation
• Site Surveys
• Topography—Aerial LiDAR
• 35% Design Milestone (April 2023)
• Bathymetry
•• , Milestone
Photo rammetr &Adit Mapping 65I Deign
Seismic March
PSHA
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*Physical
Modeling
I Modeling
PED Underway/Upcoming eGeotechnical Design September
2025
• Phase II Geotech Investigation OHydraulic Phase 11
• Hydraulic Analyses & Modeling Modeling
• Physical Modeling 100% February
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Seismic ModelingVE study Design 2025
• Industry Days (First in Spring 2024)
• 65% Design Milestone (March 2025) Contract Award
Acquisition November
35%
Construction 2026
;.
2032
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6
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U.S.ARMY CURRENT ESIGN INLET YPASS ]
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Curve designed to reduce � 0 � a a
waves and turbulences at 9
inlet�f tunnel YVNLS AND FO[inHG,
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Overflow weir section
Left training wall and
bypass structure
Existing Tunnel Entrance .:; .
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CURRENT ESIGN INLET CHANNEL
CI®R
U.S.ARMY
INLET FLUME SECTION NOTES:.
1. DIMENSIONS SHOWN ARE TYPICAL FOR EACH SIDE UNLESS OTHERWISE SHOWN.
2. ARMCF.:REBAR,ANCHORS AND ANY OTHER EMBEDDED METALS NOT SHOWN_REFER TO
OTHER SHEETS FOR THESE DETAILS_
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L {A
250 ----------------------------------r------------------T------------------7-------------------r-------------- 25D
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240 --------- - ' ----------------- ------------------T------------------7-------------------F-------------- 240 'tiw
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TOP OF WALL E4 227_44 ¢�� ✓
2, n i w a
II Iuj
?C ---------------i----------- ------i --------------- -------------- �I -------------- �-------------- 230 IL f•.
I I PIACE SOIL AT 221.8 FT.
I I r I
I I I I
II OIL TO E LPLACE II ITI�3:3QIL�71D_E_-
w
221.} t. e.INLET TUMM1EL PLAN iTA Ora-STA 6+93
22L -- -------------- ---- f 2 2 D 4 I
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IL E7(CAVATION
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ab
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1flo 110 ---- _�
-m —40 -2 C 0 2D 40 60
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STA 1+00 TYPICAL INLET SECTION SOIL FOUNDED LOOKING DOWNSTREAM
GRADING-TUNNEL-INLET AREA
Existing ground y5 -
Approach channel excavation a
lop of approach channel wall - „r
End of f
curved
.. sectiorw
Sta 10+25 n s I•. -
_ C
Invert of opproach 489X
channel,grade varies grade
Upstream portal invert®EI,177,Stc,9L11
,
PROFILE
En P�rid
mo
End of curved section)0 Sta 10+26 n -
r• 1 V,
SHOW ROCK CUT GRADING IN THE PLAN VfEW
-DETAIL ROCK SLOPE SUPPORT PLAN a 1ao° 200 F`
y"
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CURRENT ESIGN = OUTLET
U.S.ARMY
-------------------i------r------ I ----
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I I I I I I I I I I
GENERAL PLAN: ---- --i--- ------1 I I I
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-- ----L -
- I I I I I I I I
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PORTAL ROCK
1=X AVATI4N TEMPORARY _---7------r----- -------r— — ----r---- —i------r-- ----r —
BRIDGE I I ! I I I
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CUTLET FLUMEf -----J------L-----1----- ------L----- ——----L—————— —I------L--- I
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FINAL RC}Af} r }1• ��
ALICMMEI+ET ! 9TaT (FEE(
TEMPORARY
SEASIDE
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FLOW:8500 CFS DISCHARGE
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TERRACING CONCEPT
U.S.ARMY
• Terracing
will allow
Existin-g Ground
any debris 103
to flow Appro ach channel exaava icon �
away from T p :D �apprco:�h channel wall }
tunnel inlet E curvedof
section
similar to _ Sto 1 + 6
canopy
Invert of approach
channel, grade varies rage ,
�rrr, r+�al inert El. 177. #a, 9+35
12 - 15ft P,'.7
• ' F c f
slope
b chIL
- -
_ Canopy
option was = -
screened
through VE =�
process ------ .�.r
ue to cos
■ g
log ho,
save n s
�f P.
Figure 49-Entrance Portal Canopy Oblique View-
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LAYTADOWN/SGING AREAS CCRR
U.S.ARMY
Two areas identified as
potential laydown/staging
areas
Potential for utilizing
111110_ Barge to assist with
1110
staging
Disposal area —Alaska
Railroad new terminal
area
10 Miles from project
site to laydown and
staging area
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