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?