Lowell Creek Flood Diversion Project - Industry Day JUN 2025 VER1.pdf
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- Attached to
- LOWELL CREEK FLOOD DIVERSION AT SEWARD, ALASKA
- Solicitation number
- W911KB26RA003_ID
About this file
This file is an Industry Day Presentation for the Lowell Creek Flood Diversion project by the U.S. Army Corps of Engineers, Alaska District. The project involves constructing a new flood diversion system in Seward, Alaska, with key components including an inlet diversion dam, an 18-foot diameter tunnel with approximately 8,500 cubic feet per second flow capacity, an extended outlet flume, and select tree removal. The recommended plan (Alternative 4A) aims to minimize flood risks to critical infrastructure, including a hospital, senior living center, and local businesses by improving the existing flood diversion system originally constructed in 1940.
The contract (Solicitation Number W911KB26RA003) is an unrestricted, fully designed, firm fixed-price construction project with an estimated magnitude between $250-$500 million. The contract award is anticipated for the first quarter of FY27 and will be based on a tradeoff process evaluating factors such as past performance, technical approach, project execution, small business participation, and price. An Industry Day is scheduled for June 24, 2025, in Anchorage, Alaska, where potential contractors can learn about the project, provide feedback, and potentially engage in one-on-one consultations. Interested participants must submit their information by June 17, 2025, to Tammy Davis and Michelle Mandel.
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LOWELL CREEK FLOOD
DIVERSION
Industry Day 2 Presentation
Presenters:
Jathan Garrett, PM Coleman Chalup P.E., Lead Engineer
Anchorage, AK
24 JUN 2025
The U.S. Army Corps of Engineers, Alaska District, is conducting an Industry Day to improve Industry's understanding of USACE's Lowell Creek Flood Diversion project, specifically for construction of the inlet structure, 18 ft diameter tunnel and outlet flume located in Seward, Alaska, answer questions on the project and gain an understanding of how the contractor community can support this project.
Presentation Agenda (1330-1430) Welcome Introductions Project Overview
One-on-ones (1430-1530) Sign-up sheet
PURPOSE & AGENDA
CONTRACTING
• W911KB26RA003 LOWELL CREEK FLOOD DIVERSION – Unrestricted, Fully Designed, Firm Fixed-Price Construction Project
• Estimated Magnitude is $250 - $500 Million
• Award will be based on Tradeoff process described in FAR 15.101-1 to determine the proposal which represents the best value to the Government. All evaluation factors, other than price, when combined, are approximately equal to price.
• Evaluation Factors will include Past Performance, Technical Approach, Project Execution Concept/Schedule, Extent Of Participation Of Small Businesses, and Price.
• Small Business Subcontracting Plan – Required for LG Businesses - Upon request by the Contracting Officer for the apparently successful offeror
*Important: Any remarks, comments, or explanations provided during the Industry Day Conference should be verified within the future solicitation.
LOWELL CREEK DIRECTORS REPORT VIDEO
https://youtu.be/XoT5qxxVBr8?si=KmFuBXFl96-MYLlg
The existing Lowell Creek Flood Diversion System authorized by the Flood Control Act of 1936 (PL 74-738) with an authorized project purpose of flood risk management
The flood diversion system reroutes Lowell Creek through Bear Mountain and diverts flows to Resurrection Bay prior to those flows entering Seward. Completed by USACE in
Present structure has diversion dam, emergency spillway, and 10 ft tunnel that is around 2000 ft in length estimated to divert 2,800 cfs
Spillway is 800 ft upstream of critical infrastructure including hospital and senior living center
PROJECT BACKGROUND
System was designed to pass the largest event at that time of 2,800 cfs which is now considered to have greater than 2% annual chance of exceedance
Landslides are commonplace in the basin and can contribute to an outburst surge of 2.5 times larger than existing stream flow
Basin above diversion is in steep, rugged, mountainous terrain with near endless supply of sediment
Sediment is transported through the tunnel and accumulates at the outfall, which in high water events cuts off Lowell Point road access and city uses heavy equipment to flood fight/manage debris at bridge
Accumulation of debris can also damage critical infrastructure at outfall including City’s sewage treatment facility, Shellfish hatchery and Alaska SeaLife Center
PROJECT BACKGROUND CONTINUED
Identified feasible solution that provides safe, reliable, and efficient flood diversion of the waters from Lowell Creek during precipitation and surge events.
This project reduces risk to:
life safety economic damages flood fighting activities reactionary debris management costs
Project justified by reduction in risk to life safety
FEASIBILITY STUDY
OVERTOPPING INUNDATION SCENARIO
SCOUR HOLE IN EXISTING TUNNEL
EXISTING PROJECT FEATURES
N
S
EW
CURRENT DIVERSION FOR REPAIRS
2003 Repair
2017/18 Repair
The Recommended Plan as stated in the Director’s Memo is Alternative 4A Construct New Flood Diversion System
RECOMMENDED PLAN
# Components of this alternative include:
1 Inlet diversion dam
2 18-ft-diameter tunnel flow capacity ~8,500 cfs
3 Extending the outfall 150 ft to take flow and debris over the Lowell Point Road
4 Protecting the tunnel inlet from landslide with a canopy
5 Non-structural components include select tree removal
Refurbishing the existing tunnel to provide backup for new diversion system and to accept diverted flow during inspection and maintenance
65% Plans and Specs Geotechnical Data Report with Geotechnical Baseline Report Questionnaire
PROVIDED DOCUMENTS
PROJECT OVERVIEW
AREA GEOLOGY
INLET AND OUTLET BORINGS
OUTLET
AREA
INLET
AREA
CURRENT DESIGN – INLET AND BYPASS
INLET
TRAINING
WALLS
STOPLOGS
INLET
FLUME
GENERATING
POWERHOUSE
BUILDING
(PROTECT DURING
CONSTRUCTION) PERMANENT
BYPASS
CULVERT
EMERGENCY
SPILLWAY
TUNNEL
PORTAL
GENERAL
LOCATION OF
POWER SOURCE
POTENTIAL GROUND
WATER ELEVATION
INLET
AREA
CURRENT DESIGN – INLET CHANNEL
STEEL RAIL LINER
INLET FLUME PROFILE
INLET ISOMETRIC
VIEW
GROUND IMPROVEMENT
Objective Connected to inlet flume Minimize rocking of flume during seismic loading due to differential settlement Liquefaction Seismic compression
Increase kinematic dissipation of ground motions
Counter hydrostatic pressure uplift
TUNNEL
CURRENT DESIGN - OUTLET
PLUNGE POOL AREA
SEALIFE CENTER
FRESH WATER
PUMP HOUSE
TUNNEL
PORTAL
ELEVATED FLUME
DRILLED PIER
(END BEARING)
RELOCATED LOWELL
POINT ROAD
GRAYWACKE
EMBEDMENT
SLATE
EMBEDMENT
SOLIS SWITZERLAND
SEDIMENT BYPASS OUTFALL
LOWELL OUTFALL RENDITION
(8,500 CFS DISCHARGE)
BAY
EXISTING FLOOD
SEDIMENT REMOVAL AREA
OVERHEAD POWER
SEWER LINE
COMMUNICATION LINE
WATER LINE
SEALIFE WATER LINE
BURIED DEBRIS/TRAIN CAR
(1964 EARTHQUAKE)
EXISTING TUNNEL OUTFALL SEDIMENT REMOVAL VIDEO
https://youtube.com/clip/Ugkxe0ofdbe7Cect1XAjBoQi0wX0HJ0ntZh1?si=URIoVXjawROKQ7xK https://youtube.com/clip/Ugkxe0ofdbe7Cect1XAjBoQi0wX0HJ0ntZh1?si=URIoVXjawROKQ7xK
POTENTIAL LAYDOWN/STAGING AREAS
Two areas identified as potential laydown/staging areas
Potential for utilizing Barge to assist with staging
~ 10 Miles from project site to laydown and staging area across the bay
~ 60,000 cu. yds of disposal materialNS
E W
IN-WATER
DISPOSAL AREA
PROJECT SITE
LAYDOWN AND
STAGING AREA
SNOW REMOVAL AREA
SITE ACCESS
INLET AREA GRAVEL ROAD
DOWNTOWN TO OUTLET AREA
OUTFALL AREA
OUTFALL AREA
Single access route into inlet valley Use of City roads to access potential laydown areas away from project site Lowell Point Road only route to community located south of Outfall area
QUESTIONS?
| Lowell creek flood diversion |
| Purpose & agenda |
| Contracting |
| Lowell Creek Directors Report Video |
| project Background |
| Project Background continued |
| Feasibility study |
| Existing project features |
| Current diversion for repairs |
| Recommended plan |
| Provided Documents |
| Project overview |
| Area Geology |
| Inlet and Outlet Borings |
| Current design – Inlet and bypass |
| Current Design – inlet channel |
| Ground Improvement |
| Tunnel |
| Current design - outlet |
| Slide Number 21 |
| Existing tunnel outfall Sediment Removal Video |
| Potential Laydown/staging areas |
| Site Access |
| Questions? |
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