Category: Stormwater

Landfill and Stormwater Upgrades

Steel Mill Expansion – Portland, OR

An existing steel mill was looking toEVRAZ landfill expand operations by constructing a large pipe rolling mill on their property. In order to make the planned new pipe rolling mill work efficiently, rail service to the mill needed to be rerouted into the location of two existing inert material landfills. At the same time, the mill was involved with the agency to undergo a voluntary source control process to limit their input into the Portland Harbor Superfund Site. CRETE principals provided engineering, environmental, geotechnical and permitting services to modify the two solid waste landfills and managed design and construction of end of pipe stormwater treatment as a source control measure on the site.

Landfill relocation was complicated by the requirement that the project be designed and permitted with the State agency, and bid and constructed within a year to accommodate the aggressive schedule for getting the proposed new pipe rolling mill online to meet order demands. Landfill reconstruction was completed within the tight time frame required and within the allotted budget for the work.

Stormwater system upgrades were implemented to be consistent with source control for the ultimate environmental cleanup of the site. The program’s design and implementation was an interactive process with Oregon Department of Environmental Quality (DEQ) and it was executed while maintaining and accommodating key mill operations. The end-of-pipe stormwater treatment system includes wet well collection areas near former outfall discharge points, chemical treatment, pump stations to transport treatment water to a settling basin, and discharge back to existing outfall after solids settle in the basin. The remaining two stormwater basins were addressed with stormwater BMPs and infiltration.

Work Performed

  • Regulatory negotiations – DEQEVRAZ Storm Pipe
  • Geotechnical analysis and reporting
  • Permitting – solid waste, wetlands, grading, construction stormwater
  • Site cleanup and development coordination
  • Construction plans and specifications
  • Construction oversight
  • Stormwater system design

Value Added

  • Negotiated off-site wetland mitigation to provide an adequate development footprint
  • Completed permitting on a very tight time schedule by amending mill permits
  • Performed geotechnical analyses of the rail bed and landfill on the same tight schedule
  • Completed all work on schedule to allow mill expansion
  • Designed stormwater system to criteria more stringent than local codes to address potential contribution to the Superfund site
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Lake Washington Brownfield

Former Wood-Treating Plant – Renton, WA

CRETE principals led the investigation and project_sports-fields-aerialcleanup of this brownfield redevelopment project at a former wood-treating site on Lake Washington. CRETE principals completed the RI/FS, Cleanup Action Plan, Consent Decree, Engineering Design Report, and design plans and specification for cleanup of the property. Remediation on the property consisted of:

  • In situ soil mixing of source area soil and NAPLs with cement and bentonite
  • Sediment removal from a cove and restoration of a forested wetland
  • Soil capping that was fully integrated with site redevelopment
  • Relocation of a salmon-bearing stream
  • Development of site-wide stormwater management program

In situ soil mixing was implemented because geotechnical constraints at the site made excavation impractical. A cement-bentonite additive was designed to reduce the hydraulic conductivity of the impacted soil, thus restricting contaminant transport to the lake. The additive was also formulated such that the soil-additive mixture exhibited strength similar to that of the native soil. Matching native soil strength allowed flexibility in the use of foundation piles for future site redevelopment. The mixed soil was reused on-site to reduce cleanup costs.

Extensive areas of peat and other organic debris generated methane at the site. Methane mitigation systems were designed and installed in the headquarters building, indoor practice facility, and maintenance building.

CRETE principals managed the sediment remediation and wetland restoration of the cove. A one-acre emergent marsh on Lake Washington was restored to provided resident turtle habitat.

The Engineering Design Report provided adequate flexibility in schedule and cap design scenarios for the final redevelopment design to be regularly adjusted while complying with Washington State Department of Ecology requirements. The capping options included asphalt parking areas, pile-supported structures, football fields constructed of natural and artificial turf, and support areas for maintenance, emergency response, and public viewing.

CRETE principals worked with other design team members to develop a stormwater management system consistent with the 2005 King County Surface Water Design Manual. The design efficiently utilized the limited land space by infiltrating rain water through 18 inches of sand in the football field subgrade, thus satisfying the enhanced treatment requirement for discharge to the lake without using land space for a separate enhanced treatment facility. An integrated pest management plan outlines best management practices for the selection and application of turf amendments to minimize the off-site transport of pesticides and fertilizers. The design also included the use of grassy swales around the parking lot sand filters to satisfy the pretreatment requirement. The stormwater outfalls were also designed to avoid the need for USACE permitting. CRETE principals also provided construction oversight including construction stormwater collection and treatment with carbon dioxide and chitosan prior to discharge to the sanitary sewer.

The final phase of the cleanup action (environmental capping and institutional controls) was completed in 2008 in conjunction with redevelopment activities.

Work Performed

  • Property transaction due diligence
  • Regulatory negotiations – MTCA
  • Upland and sediment RI/FS
  • Permitting – in-water cleanup, wetlands, stream relocation, construction stormwater, Metro discharge
  • Sediment cleanupSeahawksSoilMixingOverview
  • Wetland restoration
  • Shoreline site cleanup and development coordination
  • Methane mitigation systems
  • Construction plans and specifications
  • Construction stormwater treatment
  • Construction oversight
  • Stormwater system design

Value Added

  • Negotiated that RCRA F-waste listings did not apply to soil and groundwater
  • Used physical criteria to minimize the volume of K001 listed waste
  • Negotiated a flexible cleanup schedule to allow coordination with development
  • Created a menu of environmental cap designs to allow multiple site development scenarios
  • Developed the CAP to allow grading and reuse of contaminated soil on site
  • Designed in situ soil mixing of source soil and NAPLs to contain source material due to geotechnical constraints
  • Designed the in situ soil mix to provide a final mix strength similar to that of soil to maximize flexibility in the use of foundation piles for various redevelopment scenarios
  • Integrated enhanced stormwater treatment features, including sand filters and pretreatment, within the environmental caps to maximize the development footprint
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CERCLA Removal Action

Lower Duwamish Waterway – Seattle, WA

T117 Historical AerialTerminal 117 is the site of a former asphalt roofing materials manufacturing facility that operated from 1937 to 1993. PCB, petroleum, dioxin/furan, and PAH impacts in soil and sediment triggered EPA to designate the site an Early Action Area of the Lower Duwamish Waterway (LDW) Superfund site. CRETE successfully worked with the Port of Seattle and City of Seattle during several phases of the project, including: 1) design and oversight of a 2006 time-critical removal action in the Upland Area; 2) preparation of an Engineering Evaluation/Cost Analysis; 3) design of a non-time-critical removal action (NTCRA) in the Upland and Sediment Areas; and, 4) NTCRA bidding and construction support.

Key elements of the NTCRA included:

  • Pre-design and pre-confirmation soil, sediment, and geotechnical sampling
  • Removal of 46,000 cubic yards of soil and sediment in an Environmental Justice neighborhood
  • Special approval by permitting agency to conduct in-water and riverbank work outside of the standard in-water work window established for protection of salmonids
  • Deconstruction and diversion for re-use of existing site building materials
  • Utilized adjacent commercial facilities for construction haul roads and storage to minimize impacts on the residential community
  • Integrated the design with planned right-of-way cleanup activities by the City of Seattle
  • Performed a Cultural Resource Assessment with reporting to the Tribes and the State Historical Preservation Office
  • Prepared the technical bid documents for public bid, including the Port of Seattleā€™s first use of responsibility criteria

Upland construction was completed in the summer of 2014. The majority of the in-water work was completed in the winter of 2014 and the remainder was completed during the 2014/15 in-water work window.

Work Performed

  • Regulatory negotiations – CERCLA/MTCAT117 Completed Bank
  • Permitting – TSCA risk-based disposal approval, EPA off-site rule, ESA Section 7 biological assessment, cultural resource assessment
  • Sediment and upland cleanup design and bid documents
  • Construction oversight
  • Upland and sediment EE/CA
  • Insurance cost recovery
  • Groundwater-surface water fate and transport
  • Dioxin forensics

Value Added

  • Implemented project within an Environmental JusticeĀ residential area with intensive stakeholder involvement
  • Designed the cleanup to integrate with adjacent cleanups, utility improvements, and future site development of a habitat mitigation site
  • Obtained a non-potability determination for site groundwater
  • Negotiated cleanup levels incorporating groundwater-surface water attenuation due to tidal influence
  • Participated in a dioxin forensics work group that concluded that the site was likely not a significant contributor of dioxins to the neighborhood
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