Predictive Modeling and Design Solutions for Beneficial Use of … … · Overview of Presentation • Introductions • Examples and design considerations of beneficial use (BU)

Predictive Modeling and Design Solutions for Beneficial Use of Dredged Material


Presented by Tom Wang, P.E., and Kathy Ketteridge, Ph.D., P.E.January 28, 2016


Overview of Presentation

• Introductions

• Examples and design considerations of beneficial use (BU) opportunities

• Predictive modeling for BU

• Dredging, transport, and placement methods for BU

− Innovative construction materials and methods

• Case study discussion

• Questions


Integrated Approach is Key to Success

Design for Beneficial Use

(BU)

Constructability Concerns

Construction Equipment and

Methods

Predictive Modeling

Goals of BU Project


Beneficial Use Design Guidance

• USACE publications− EM 1110-2-5026 Dredged

Material Beneficial Uses

− DRP and DOER papers and case studies

• USEPA− EPA842-B-07-001 Beneficial

Use Planning Manual


Beneficial Use (BU) Opportunities


Beneficial Use Opportunities

Confined Disposal

Facility (CDF)–Shoreline

Development

Shoreline Remediation

Cap

Confined Aquatic

Disposal (CAD)


Beneficial Use Opportunities, continued

Habitat Restoration -

Mitigation

Beach Nourishment


Predictive Modeling for BU Projects


Physical Stability of Placed Sediment• Objective: Evaluate short- and

long-term physical stability of placed material due to hydrodynamic forcing

• Tools: ADCIRC, STWAVE, Delft-3d, SWAN, M2D and others

• Data needs

− Site conditions

− Design conditions

− BU sediment characteristics

Maximum Predicted Current Field Around BU Island (M2D Model)


Physical Stability of Placed SedimentHydrodynamic Forcing Conditions• Tidal currents

• Estuarine processes

• Wind-waves

• Vessel wakes

• Propeller wash

• Riverine currents

• Outfalls/stormwater

Simulation of Hurricane Katrina for Port of Gulfport (wind stress)


Keyport Lagoon, U.S. Navy

Tidal Currents (ADCIRC) and Excess Shear Stress


Hancock County Living Shorelines, Mississippi Sound

Wave Energy along Shoreline (SWAN)


Esquimalt Harbour, British Columbia, Canada

Prop Wash Evaluation

• CFD Code• Need to predict

specific velocity field behind the prop

• Evaluate scour potential based on predicted velocity field

• Example shows velocity field around constructed containment wall


Sustainability (SLR)

• Objective: Evaluate impacts to project over design life based on predictions of sea level rise

• Tools: Hydrodynamic models and GIS spatial modeling tools

• Data needs

− Site conditions− Design conditions− Habitat conditions and characteristics− Sea level rise estimates (typically

through 2100)

Transformation of Tidal Wetlands in DE


Geotechnical Modeling• Dredged

material bulking and settlement (short-term)

• Foundation consolidation (long-term)

• PSDDF Model

– Settlement during construction

– Long-term consolidation


Contaminant Mobility (Benthic)

• Mobility of contaminants through the placed sediments

• Groundwater pathways

• Reible Model (1998 EPA Cap Guidance document)

• AQFATE


Contaminant Mobility(Suspended)

• Objective: Assess water quality impacts resulting from dredging

− Turbidity− Dissolved contaminants

• Tools: ADDAMS DREDGE and STFATE modules; EPA Plumes

• Data needs − Site conditions− Sediment characteristics− Dredge characteristics and

operations− Disposal operations


Summary of Predictive Modeling for BU

+ Considered++ Important+++ Critical for Design

Beneficial Use Options Physical Stability

Sustain-ability

Contaminant Mobility (Benthic)

Contaminant Mobility (suspended)

Geotechnical Considerations

Confined Disposal Facility/ Shoreline Development

+++ + +++ +++ +++

Confined Aquatic Disposal +++ ++ +++ +++ +++

Beach Nourishment +++ + +

Habitat Restoration/Mitigation +++ +++ ++ +++

Sediment Remediation Cap +++ +++ +++ +++


Dredging, Transport, and Placement• Key considerations in equipment and method selection

− Intended beneficial use of dredged materials at placement site

− Distance between dredge and placement sites

− Dredging vs. placement production rates

− Substrate suitability of dredged material for beneficial use

− Sediment contamination

− Placement site timeframe to achieve functionality

• Short-term dredge material bulking and settlement

• Long-term consolidation (sediment and foundation)

− Dewatering or treatment needs


Dredging, Transport, and Placement (cont.)• Key considerations in equipment and method selection

− Predictive modeling results

− Empirical laboratory or bench-scale testing results

− Environmental impacts

• Water quality impacts at dredge and placement sites

• Habitat impacts

• Ability to employ construction BMPs to mitigate impacts


Dredging, Transport, and Placement (cont.)

Beneficial Use Options Dredging Method (Mech, Hydr)

Transport Method (Barge, Pipeline)

Clean or Contam.Sediment

Active DewateringTypically Used

Treatment Typically Used

Confined Disposal Facility/ Shoreline Development

Both Both Both Yes Sometimes

Confined Aquatic Disposal Mechanical Barge Both No No

Beach Nourishment Hydraulic Pipeline Clean No No

Habitat Restoration/Mitigation Both Both Clean No No

Sediment Remediation Cap Mechanical Barge Clean No Sometimes


Dredging and Transport Technologies• Mechanical

– Barge transport– Unlimited transport distance– Low bulking (i.e., near in-situ)– Intermittent placement– Debris is relatively easy– Lower production rate

• Hydraulic– Pipeline transport– Restricted transport distance– High bulking (i.e., hydraulic slurry)– Continuous placement– Debris is challenging– Higher production rate


Mechanical Dredging Technologies

Derrick Dredge (aka Clamshell Dredge)


Hydraulic Dredging Technologies

Swinging Ladder Cutterhead Dredge


Hydraulic Dredging Technologies (cont.)

Trailing Suction Hopper Dredge


Dredged Material Transport and Screening

• Transport equipment depends on dredge type and staging/processing needs

− Barge transport

− Pipeline transport

− Staging area availability and size

• Staging/processing depends on final placement site

− Debris screening

− Dewatering

− Treatment

− Overland transport


Mechanical Dredge – Barge Transport


Hydraulic Dredge – Pipeline Transport


Screening Debris


Mechanical Placement

• Barge transport for dredged material

• Capable of placing wide variety of material

• Multiple placement methods: barge, rehandling, conveyor, tremie

• GPS enabled for documentation of area coverage

Barge placement

Telebelt placement

Thin layer placement with rehandling bucket


Hydraulic Placement

• Slurry transport via hydraulic pumps and pipeline

• Barges equipped with anchoring system and GPS

• Ideal for sand and finer material up to 1 inch in diameter

• Thin layer cover combines dredging and precision placement, restores marsh elevation

Hydraulic with diffuser screen

Hydraulic diffuser

Thin layer capping over marsh


Sediment Dewatering

• Passive dewatering– Stockpiles, barge dewatering– Wick drains– Surcharging– Effectiveness varies with material type– Less certainty

• Geotubes (hydraulic dredging)– Contained passive dewatering– Need space and time– Used for beach nourishment, temporary berms,

contaminated sediment dewatering

• Active dewatering– Filter or belt press (mechanical or hydraulic

dredging)– Hydrocyclone for size separation– More certainty


Empty Geotubes Prior to Filling


Full Geotubes Releasing Water


Excavating a Full Geotube


Active Dewatering Equipment


Hydrocyclone Size Separation


Slurried dredge material

Contaminated fines and water

Washed sand

Hydrocyclone Size Separation (cont.)


Treatment – Stabilization

• Adding lime/cement/other to

– Bind up water

– Reduce chemical leachability

– Increase strength

• Can be simpler than dewatering

• Typically used to address site stability or strength needs, or sediment contaminants


Confined Disposal Facilities


CDF Design Guidance

• U.S. Army Corps of Engineers publications

– EM 1110-2-5025 Dredging and Dredged Material Disposal

– EM 1110-2-5027 Confined Disposal of Dredged Material

– Dredging Research Program (DRP)

– Dredging Operations and Environmental Research (DOER)

– EM 1110-2-1902 Slope Stability

Source: http://www.publications.usace.army.mil/USACEPublications/EngineerManuals.aspx


CDF Design Considerations

• Containment design – Static and seismic stability

– Contaminant mobility

• Size and capacity– Short-term bulking and settlement


– Ponding area to meet water quality criteria

• Pumping distance– Water content

• Site final use– Habitat

– Shoreline development

– Recreation


Milwaukee Waterway NCDF and Habitat


Milwaukee Waterway NCDF and Habitat


Confined Aquatic Disposal


Confined Aquatic Sites

• USACE Publications– EM 1110-2-5025 Dredging and

Dredged Material Disposal

– EM 1110-2-5027 Confined Disposal of Dredged Material

– DRP and DOER Reports

• USEPA– Ocean Disposal Manual

– CAD designs


CAD Design Considerations

• Submerged or emergent• Containment design

– Static and seismic stability

– Erosion protection

– Contaminant mobility

• Size and capacity– Short-term bulking and settlement


• Sustainability

• Pumping distance– Water content

• Site final use– Typically habitat function

– Navigation and anchoring restrictions


48

Place Contaminated Sediment in CAD

Port Hueneme Beneficial Use

Place CAD Clean Sediment as Beach Nourishment

CAD


Port Hueneme CAD Cross-section

-85’ MLLW

-56’ MLLW

-46’ MLLWClean Cap

Contaminated Sediments

-43’ MLLW

Note:MLLW = mean lower low water


Port Hueneme, USACE, U.S. Navy

Port Hueneme – Barge Placement


Port Hueneme – Barge Placement

Port Hueneme, USACE, U.S. Navy


Beach Nourishmentand Habitat Restoration


Other Beneficial Uses

• Beach nourishment

• Agriculture and products– Topsoil– Aquaculture

• Berms– Stable and feeder

• Habitat restoration

• Land improvement

• Marsh and intertidal habitat


Parallel Geotextile Tubes in Perimeter Dikes


Deer Island Marsh Creation

• Design elements

– 7- to 8-foot-high dike

– Easterly wing dike

– Flash board riser weirs

– Offset to provide bayou

• Dredged material from Biloxi Lateral Channel

• Approximately 40 acres were filled with 365,000 cy of sediment


Enhancing Existing Marsh

Illustration of conceptual model for marsh recovery after thin-layer disposal


Case Study: GP Log Pond


GP Log Pond Remediation and Habitat Creation

• Cost-effective sediment remediation alternative

• Cap in place >130,000 cy industrial waste product

• Beneficial reuse of 43,000 cy of dredged material

• Restoration of 5.6 acres of intertidal and shallow subtidal habitat


GP Log Pond


Wave Modeling for Cap Stability

Whatcom Waterway

GP Log Pond


Habitat Creation Criteria


Key Design Considerations• Dredge material as habitat cap

– Swinomish Channel and Squalicum Harbor combined dredge materials

– Fine to medium sand + slightly sandy, clayey silt (MH)

• Coastal stability and sea level rise– Shoreline and cap armoring

• Long-term consolidation– Habitat elevations for eelgrass

• Contaminant mobility– Groundwater transport

– Contaminant isolation

• Mechanical methods– Limit water quality impacts

– Placement precision



Questions?

Predictive Modeling and Design Solutions for Beneficial Use of … … · Overview of Presentation • Introductions • Examples and design considerations of beneficial use (BU)

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