EXPANSION OF THE SMALL SCALE
PHYSICAL MODEL (SSPM) OF THE
LOWERMOST MISSISSIPPI RIVER DELTA
PRESENTATION OVERVIEW
• Current Small Scale Physical Model (SSPM)
– History
– Goals and Objectives
– General Features
– Results and Conclusions
• Expanded SSPM
– Project Team
– History
– Goals and Objectives
– Alternatives Analysis
– Engineering and Design
– Schedule
• Questions
CURRENT SSPM
History
– Designed by LDNR/BCG in 2002
– Constructed and Calibrated at SOGREAH (France) in 2003
– Shipped to Louisiana and reassembled at facility on LSU’s campus
– Initial Model Program performed in 2003/2004
– Final Report issued in December 2004
– Cost: ~$840,000 for Engineering, Model Construction, and Model
Facility.
CURRENT SSPM
Goals and Objectives
– Establish baseline feasibility study for sediment management
– Explore combinations of large and small diversions
– Study feasibility of delta returning to its natural state (by reducing
or eliminating dredging)
– Consider navigation needs
– Education, presentation and identification of alternatives for
further investigation
CONCEPTUAL PLAN FOR
DIVERSION CHANNELS
• 3 large (600K cfs) diversions
• 12 small (100K -200K cfs) diversions
• Slack-water Navigation Channel w/ two lock gates
• West Bay Sediment Diversion (50K cfs)
• Bohemia Spillway / Pointe a la Hache Relief Outlet (up to 250K cfs
natural overflow to the east)
CURRENT SSPM
• Horizontal scale
1:12,000
*
Pointe a la Hache, LA
• Vertical scale 1:500
• Approximate
prototype area = 3500
sq. mi. (55 miles X 63
miles)
• 76 river miles
represented on SSPM
*
Venice, LA
CURRENT SSPM
CURRENT SSPM
Conclusions/Results
– Currently virtually no land building/diversion benefits occur on
the West Bank of the Lower Delta;
– With no change in current sediment management practice,
dredging requirement will greatly increase (after 100 years of
relative sea level rise, ~70% of all transported sand will need to be
dredged);
– Large Diversion operating during high River flows showed
extensive land building on the West Bank of the Lower Delta;
– With Large Diversions operating during high River flows,
virtually no dredging occurred during the first 50 years (some
dredging occurred in the latter 50 years after significant RSL)
CURRENT SSPM
BASE CASE SCENARIO
After 100 years operation
CURRENT SPPM
LARGE DIVERSION #2
After 100 years operation
CURRENT SSPM
Conclusions/Results
– Additional domain space upriver and downriver could’ve
produced better results in certain situations;
– Scale/distortion prevented modeling of more realistic sized
diversions(minimum 100,000 cfs);
– Modeling facility/work environment issues;
– Modification to existing diversion scenarios, or addition of new
diversion scenarios, was not easily implemented.
EXPANDED SSPM
Planning Phase
Project Team
– CPRA
– Louisiana State University
• Dr. Clint Willson
– BCG-Dewberry JV Team:
• BCG - Ken Brown, Cecil Soileau, Ike Mayer, David Dodgen, Robert Tisdale,
Sultan Alam
• Dewberry -Skip Notte, Jerri Daniels
• Computational Hydraulics and Transport
• Mobile Boundary Hydraulics
• C & C Technologies
• Eustis Engineering Services
– Senior Advisory Panel
•
•
•
•
•
•
•
Dr. Chester Watson – University of Colorado
Dr. Daniel Gessler – Alden Research Laboratory
Dr. Alex McCorquodale – University of New Orleans
Dr. Forrest Holly – University of Iowa
Dr. Allison Mead – University of Texas
Dr. Allen Teeter – Computational Hydraulics and Transport
Sultan Alam – BCG-Dewberry JV
EXPANDED SSPM
Planning Phase
History
– LSU reported that the Current SSPM was reaching the end of its
useful life in June 2010
• Extensive leaking between panels;
• Rotting of plywood base;
• Warping/disfiguration of model panels.
– CPRA tasked BCG in December 2010 to assist in the
investigation of the SSPM’s future
– In February 2011 BCG reported that 11 of 24 SSPM panels
needed to be replaced
– CPRA initiated the Feasibility Study on Rehabilitation,
Modification, and Expansion of the SSPM
EXPANDED SSPM
Planning Phase
Goals and Objectives
– Forecast land building potential of major diversion;
– Qualitatively evaluate resulting impacts of doing nothing;
– Forecast future dredging required to maintain navigation;
– Accurately depict the impact of RSL on the Lower Delta.
EXPANDED SSPM
Planning Phase
Goals and Objectives (continued)
– Evaluate and demonstrate sediment management solutions that
help address navigation concerns;
– Optimize location and operation of proposed diversions;
– Identify the impacts of proposed diversions on navigation;
– Evaluate the impacts of proposed diversions on other diversions;
– Demonstrate methods of storing sediment in deep river section to
reduce dredging.
EXPANDED SSPM
Planning Phase
Alternatives Analysis
Assessed advantages/disadvantages, design criteria, and costs of three
alternatives:
1.
Rehabilitate existing SSPM and expand area modeled upriver and
downriver one panel in both directions.
2.
Modify existing SSPM by replacing test bed and extending model
upriver to above Bonnet Carre’ Spillway and downriver one panel.
3.
Construct a new SSPM with a larger scale to expand area modeled to
area bounded to the West by the Terrebonne Ridge, RM 150 upriver,
to the East by the North Shore of Lake Ponchartrain and to the south
500 ft. contour in the Gulf of Mexico.
4.28 m
(Model to
Wall)
ALTERNATIVE 1 – Scale and Domain Unchanged
North
7.41 m (Model Length)
8.46 m (Model Width)
(Model
to Wall)
(Partition to
Catwalk Rail)
5.41 m
10.26 m (Width b/t Catwalk Rails)
Entrance
14.68 m (Building Width)
22 m (Building Length)
3.12 m
2m
ALTERNATIVE 2 – Scale Unchanged, Domain Increased
10.91 m (Model Width)
22 m (Building Length)
12.21 m (Model Length)
North
2.89 m
12.23 m (Width b/t Catwalk Rails)
Entrance
14.68 m (Building Width)
ALTERNATIVE 3 – Scale and Domain Increased
EXISTING
MODEL EXTENTS
16.9 meters (model)
14.6 meters (model)
108.8 miles (prototype)
126.4 miles (prototype)
EXPANDED SSPM
Planning Phase
EXPANDED SSPM
Planning Phase
Alternatives Analysis
Scope and Schedule:
– Work Group Meeting #1: January 27, 2011
– Technical Meeting #1: February 7-9, 2011
– Technical Meeting #2: April 26-28, 2011
– Working Group Meeting #2: May 12, 2011
– Technical Meeting #3: June 26-29, 2011
– Working Group Meeting #3: August 3, 2011
EXPANDED SSPM
Planning Phase
Alternatives Analysis
Results:
– Alternative 1 ($1,343,200)
• Pros: Lowest cost; shortest implementation time
• Cons: Due to unchanged domain and scale/distortion, no new goals could be
accomplished
– Alternative 2 ($1,584,400)
• Pros: Low cost; Expanded domain could allow new modeling scenarios
• Cons: Due to unchanged scale/distortion, no diversion smaller than ~100,000
cfs could be modeled
– Alternative 3 ($4,198,200)
• Pros: Expanded domain and scale would allow diversion as small as ~25,000
cfs to be modeled; new goals could be accomplished.
• Cons: New facility; highest cost; longest implementation time
EXPANDED SSPM
Design Phase
Schedule
– CPRA Executive Division authorized engineering and design of
Alternative 3 in September 2011
– Design Scope and Schedule developed by CPRA and BCG in
October 2011.
– Notice to Proceed Issued on January 5, 2012
– Project Team Kick Off Meeting held on January 19, 2012
– Pre-Design Meeting held on February 1, 2012
– Engineering and Design to be completed by October 2012
EXPANDED SSPM
Design Phase
Alternative 3 – Facility
– World Class Modeling Facility
•
•
•
•
•
Space to construct/operate other smaller scaled physical models;
Fully staffed, fully operational hydraulic laboratory;
State of the art audio/visual and presentation capabilities;
In-house computational modeling facilities;
Visitor friendly features.
EXPANDED SSPM
Design Phase
Alternative 3 - Construction
– Computer Numerically Controlled (CNC) Router
•
•
•
•
Uses CAD input files to route surface of 4 ft. x 8 ft. high density foam panels;
Facilitates fast, high accuracy model bed construction;
Allows for interchangeable model panels;
Would be used to construct other models at the proposed facility.
EXPANDED SSPM
Design Phase
Alternative 3 - Operation
– Fully Automated Operation Systems
• Sediment injection
• Water elevation monitoring
• Overhead photography/videography
– Interchangeable Model Panels
• Overhead crane/hoist
– Model Domain Accessibility
– Remote Controlled Dredging
– Water System
• Rehandling
• Temperature control
QUESTIONS
Rudolph A. Simoneaux III, P.E.
Coastal Protection and Restoration Authority
Restoration Division
rudy.simoneaux@la.gov