Post on 13-Jan-2016
Case Study: Case Study: Campmarina Campmarina
Sheboygan RiverSheboygan RiverSediment Removal ProjectSediment Removal Project
Project IntroductionProject Introduction
Sheboygan River, Sheboygan, Wisconsin
Parties Owner: Wisconsin Public ServiceWisconsin Public Service
Contractor: Envirocon, Inc.Envirocon, Inc.
Engineer: Natural Resources TechnologyNatural Resources Technology
Key Subcontractors: McMullen & Pitz, Gillen, & Green Globe EnvironmentalMcMullen & Pitz, Gillen, & Green Globe Environmental
Former MGP Site COC’s: TSCA & Non-TSCA PCB’s, NAPL, & PAH impacted sediments
Existing Waterloo Wall from earlier Superfund project
Site is a city park in a residential neighborhood
Scope of WorkScope of Work
Remove 20,113 BCY 20,113 BCY of impacted sediments by mechanical dredging
using a CAT 345 on sectional barges (flexifloats) TSCA PCB’s: 1,177 BCY1,177 BCY, “Surgically Removed”
Non TSCA PCB’s, PAH’s, & NAPL: 18,936 BCY18,936 BCY
Supplemental: 6,000 BCY, only 900 BCY 900 BCY (North Supplemental) removed
Stabilize sediments for off site disposal (TSCA to a hazardous waste
facility, Non-TSCA to a non-hazardous landfill)
Install buttress system for waterloo wall
Ancillary work items: Install and remove sheet pile coffer dam, restore
bank, remove Wakefield Wall, treat up to 2.6M gallons of water, control
sediment odor
Site Overview Site Overview Site Laydown
Stabilization Pad
H2O Treatment
Sheetpile Coffer
Buttress System
Dredge
Boat Island
Condos
Design Overview Design Overview
Key Topic AreasKey Topic AreasExisting Waterloo Barrier & CapExisting Waterloo Barrier & CapSetting: residential neighborhood & city parkWaterloo barrier and cap = LGP, mats & deflection monitoring
Project Coordination & SequencingProject Coordination & SequencingNo TSCA / Non TSCA cross contaminationButtress of waterloo barrier before sediment removal
Odor ControlOdor ControlNAPL, PCB, and PAH impacted sediments, NAPL being most odorous from coal tarAir monitoring (suma canisters), dust monitoring, and odor control measures
Water TreatmentWater TreatmentTSS (total suspended solids) removal key to prevent PCB exceedance Batch filtration proved effective
Guidance System IssuesGuidance System IssuesHypack Dredgepack used on the mechanical dredgesChange implementation on complex site models
Sequencing & LogisticsSequencing & Logistics
Key Challenges:Key Challenges: Installation of sheet pile coffer dam Removal of TSCA material separate from Non-TSCA material Stabilization of sediments Installation of buttress system / deflection monitoring / LGP on the cap & wall Removal of Wakefield Wall Work coordination with a separate but adjoining dredging project
Coffer Dam ConstructionCoffer Dam ConstructionSheet pile coffer dam was used to contain suspended solids, especially in areas with TSCA PCB contaminated sediments.
DetailsDetails 2 wings, North & South Between Boat Island & East Shore 35’ long Z pile Vibrated in place Installed by M&PButtress install and dredging simultaneous with coffer dam install
Buttress ConstructionButtress Construction Existing Waterloo wall was not tied into bedrock. There was concern that the existing
capped and remediated Superfund site (the park) could deflect when removing sediments against it, breaking the grouted joints and causing leaking into the river. Deflection monitoring and LGP measures implemented on the Waterloo wall and cap
Impacted sediments removed by jetting along the Waterloo wall to allow for the installation of the wales
Buttress System: 42” diameter steel pipe, 40’ long, double I-beam wales between Waterloo wall and 42” pipe
A wood wakefield wall was discovered along the buttress alignment. Much of the wall had to be sheared off.
Odor ControlOdor ControlGiven the Site location in a residential area and the odorous nature of the NAPL MGP coal tar residuals (much like moth ball odors), extensive control measures were taken.
Key Control Measures:Key Control Measures: Rusmar foaming of pile Ecosorb “Air Fresheners” Tarping of the pile
LKD was used to stabilize the sediments to pass the paint filter test. One consequence of LKD addition is that it heats the pile which promotes off-gassing. Approximately 2,000 BCY of sediments were stored and stabilized on the pile at any given time.
Water Treatment SystemWater Treatment System
Permit Requirements: PCB Total: 0.8 mg/L daily maximum PAH’s: 0.1 mg/L monthly average TSS: 10 mg/L daily maximum
Plant sized to handle 50 GPM and 2.6M gallons 50 GPM and 2.6M gallons over the project duration
Plant treated water from: stabilization pad, free liquids at the sediment offload, decontamination water
Key components: positive displacement pumps and piping, geotubes, weir tanks, bag filters, sand filters, and carbon filters
Water Treatment System PFDWater Treatment System PFD
Guidance System & Technology Guidance System & Technology SolutionsSolutions
Final grade models consisted of:TSCA PCB’s: 0.5’ x 0.5’ gridNAPL: flat bottom elevationsPAH’s: contoured grades
Modeling methods:Hypack does not import TIN surfaces from Autodesk Civil 3D. Models were created in Civil 3D. Then a 0.5’ x 0.5’ grid was lifted from the designed surface. This XYZ file was then used in Hypack/DredgepackCivil 3D does not quickly make the grid but several add-ins do.
Numerous design changes, meant numerous model changes
Existing grade updated using Hydrolite Single Beam Sonar, multiple times per week. Sonar used for both QA and QC bathymetric surveys.
Model ChangesTSCA by cut from OGTSCA cut to provided ptsNAPL: Visual depthsPAH’s: 3 added contoursDTM implications and horizon lines.
Guidance System & Technology Guidance System & Technology SolutionsSolutions
SPS 852 base station (GNSS enabled), 450 mhz radios (Trimmark 3), GNSS enabled RTK receivers, 880 Extreme rover and SPS 700 robotic total station, Hydrolite Sonar. Etrac sensors for the guidance system.
Complex models. NAPL was cleaned until visually removed (core samples). Depth revised throughout. Vertical edges, no laybacks. Tolerances were at grade to -0.5’ below grade.
“Surgical Removal” of TSCA areas
Software solutions: Autodesk Civil 3D, Terramodel, Logmein, and Hypack
Questions?Questions?