Liberte Environmental Associates

LEA Projects


Mudline Cellar Design Response to Ice Keel and Ice Scour

Water Quality and Related Technical Assistance
For Oil and Gas NPDES Permitting and Exploration Plans
For North Slope Borough, Alaska

Evaluation of US Environmental Protection agency NPDES permit for discharges from oil and gas facilities including discharges from: drilling operations, cooling water intake and discharge, storage facilities, stormwater, pipelines, gravel pits, treated sewage discharges, maintenance requirements, and other types of discharges. These discharges include cooling water intake and thermal discharges, stormwater affected deck drainage, treated sewage discharges and drill cuttings disposal to marine sediments. Water quality evaluation of the Camden Bay Exploration Plan for the Beaufort Sea of the Arctic Ocean was conducted for discharge impacts on the marine aquatic environment and relative to BOEMRE/MMS EIS. Analysis of the Chukchi Sea Exploration Plan of the Arctic Ocean was conducted for discharge impacts on the marine aquatic environment and relative to BOEMRE/MMS EIS. These evaluations were based on water quality and treatment alternatives assessment, and comparison to biological criteria. Design based comparison at the 0.5 fps intake velocity criterion was performed for large flows 316(b). Alternatives comparison comprised: non-contact cooling water operations, thermal discharge minimization and mitigation, secondary sewage treatment, stormwater treatment; off-site disposal or deep well injection of drilling muds and cuttings.


Pudding River Downstream of Aurora STP

Aurora STP NPDES Assessment
Related to the Design, Operation and Monitoring
Of the Aurora, Oregon Sewage Treatment Plant

Review of documents and assessment related to the design, operation and monitoring of the Aurora, Oregon Sewage Treatment Plant. Review documents included: NPDES permit; design related plans and specifications including recent headworks unit design; discharge monitoring reports, irrigation using effluent reuse, biosolids monitoring reports; effluent reuse plan and additional information relating to the design and operation of the Aurora STP. The review provided a basis for assessing potential causes of facility underperformance and discharge violations. An STP site visit was performed during this project to investigate facility aeration treatment, reuse equipment and capacities.



Skipanon River

Expert Analysis of Surimi and Seafood Wastewater Discharge
Into the Skipanon and Columbia Rivers, Oregon
For National Environmental Law Center

Water quality analysis evaluating the effects of seafood and surimi wastewater discharges on the Skipanon and Columbia Rivers, Oregon. Field data collection was performed to support water quality technical analysis. Investigation included mixing zone analysis of historic seafood and surimi wastewater discharges into the Skipanon River, and new discharges to the Columbia River. Evaluations were performed for various discharge scenarios, monitoring and sampling requirements, potential treatment options, and alternative outfall pipeline alignments. Effluent and instream dissolved oxygen (DO), biochemical oxygen demand (BOD), ammonia, hydrogen sulfide, nutrients nitrogen and phosphorus, oil and grease, and total suspended solids (TSS) were evaluated in detail. Expert witness analysis and reporting was provided. A discussion of the suit is available at the NELC website at NELC Wins Landmark Ruling in Clean Water Act Enforcement Lawsuit. Also available is the Preliminary Injunction Order issued by the United States District Court for the District of Oregon.


Cook Inlet


Review of Draft NPDES General Permit
Cook Inlet, Alaska Oil and Gas Operators
For Cook Inletkeeper

Expert review of the draft National Pollutant Discharge Elimination System (NPDES) permit proposed by the U.S. Environmental Protection Agency (EPA) authorizing wastewater discharges from oil and gas exploration, development, and production facilities into Cook Inlet, Alaska. There are 18 existing facilities discharging into Cook Inlet with new facilities capable of being brought on line under the draft permit. Technical analysis of these discharges, which can contain toxic and bioaccumulating contaminants, was performed relative to the potential to adversely affect Cook Inlet water quality and sediments. A copy of this evaluation report can be obtained from LEA's website at Review of Draft NPDES General Permit For Cook Inlet, Alaska Oil and Gas Operators.





Puget Sound

Effect On Puget Sound Chinook Salmon
Of NPDES Authorized Toxic Discharges
For Public Employees for Environmental Responsibility

Coauthor of the report Effect On Puget Sound Chinook Salmon Of NPDES Authorized Toxic Discharges As Permitted by Washington Department of Ecology. LEA performed water quality technical analysis of NPDES permits issued by Ecology, and having potential toxic effects of salmon and other species in the Puget Sound. Facilities fact sheets were also evaluated. Washington Ecology ambient sampling databases, related to water quality and sediments, were analyzed in detail. A copy of this evaluation report can be viewed on the PEER website at Effect on Puget Sound Chinook Salmon of NPDES Authorized Toxic Discharges as Permitted by Washington Department of Ecology. A copy of this report is also available from LEA's website.








South Fork Spencer Creek

Potential of Metals and PAH Contamination From
Shooting Range in South Fork Spencer Creek
For Citizens for Responsibility

Expert witness and analysis for plaintiff evaluating the effects of potential toxic contamination from shooting range into South Fork Spencer Creek for case in Circuit Court of the State of Oregon for Lane County. Sediment sampling was conducted for metals including lead, arsenic, copper and polynuclear aromatic hydrocarbons (PAH). This information was evaluated for pollutant distribution and transport from the contaminated site and relative to upstream and downstream properties. Expert testimony was given at trial in 2004. Expert analysis and testimony was also provided in the subsequent equitable relief phase. Participation in the settlement conference was also provided.

Mapping of effluent plume with mixing zone

Water Quality Technical Assistance - Outfall MZ Analysis & Design Assessment
For Oregon Department of
Environmental Quality

LEA provided environmental engineering assistance to the DEQ. Work included receiving water quality analysis, outfall design review and mixing zone analysis. NPDES requirements are based on EPA Quality Criteria for Water, EPA Technical Support Document for Water-based Toxics Control (TSD) and State Administrative Rules.

Potential discharge chlorine residual and temperature requirements were evaluated. The effect of potential temperature Total Maximum Daily Loads (TMDLs) in the Columbia River was also emphasized.


Water Quality Evaluation, Mixing Zone Field Studies and NPDES Permits Requirements
For Water Environment Services, Clackamas County, Oregon

LEA taking current velocity measurements mid-river LEA provided project management and environmental engineering for this extensive project to evaluate river discharge conditions through modeling analysis and direct field measurements. Water quality requirements evaluated included NPDES permitting and anti-degradation for all four (4) of the Water Environment Services Water Pollution Control Plants (WPCP).

Technical and scientific information was reviewed including Discharge Monitoring Reports (DMR) in determination of existing and potential future water quality needs and requirements. This analysis was performed for a range of WES discharge receiving waters including two on the Willamette River, one on the Sandy River and one on a small tributary of the Clackamas River.
Plan and profile drawing of outfall diffuser
Alternative discharge evaluation was performed relative to outfall design and cost. LEA also evaluated water quality requirements for temperature, ammonia, metals, chlorine and other water quality parameters with facility design implications including de-chlorination, aeration capacity and river diffusers. Data and information related to water quality impacts on threatened and endangered species was evaluated. This included identification and requirements of affected state and federal regulatory agencies to ensure that receiving waters will not be impaired. Potentially affected agencies were the US Army Corps of Engineers (COE), Oregon Division of State Lands (DSL), National Marine Fisheries Service (NMFS), Oregon Department Fish and Wildlife (ODFW), US Fish and Wildlife (USFW) and others.

Discharge temperature requirements resulting from potential Total Maximum Daily Loads (TMDLs) were evaluated for WES receiving waters. In particular, the potential effect of the USEPA Region 10 Draft Guidance for State and Tribal Temperature Water Quality Standards was emphasized.









Mixing Zone Evaluations and Diffuser Designs
For City of Portland, Bureau of Environmental Services

Diffuser port velocity comparison with salmon requirements


LEA was the project engineer responsible for evaluating the effect of wet and dry weather chlorine residual discharges to the Columbia River. This evaluation was based on various facilities flows up to 360 mgd as well as varying river flow conditions.



Through the years, LEA's Dave LaLiberte has been directly involved with BES and DEQ staff regarding NPDES permitting requirements. Dave's mixing zone analysis and engineering criteria provided the design of both of BES's large (84-inch) outfalls and diffusers. Particular emphasis was placed on allowable effluent chlorine residual, ammonia, metals and dissolved oxygen. Mixing zone modeling was performed for both wet and dry weather outfalls.

Diffuser port velocity comparison with salmon requirements

Data and information related to water quality impacts on threatened and endangered species was evaluated. Potentially affected agencies included US COE, Oregon DSL, NMFS, ODFW, USFW and others. Alternative discharge evaluation was performed relative to design and economic cost-benefit analysis. Dave has also evaluated water quality requirements for ammonia, DO, metals and chlorine with facility design implications for de-chlorination and aeration capacity.


Water Treatment Plant NPDES Permit Project and Predesign
For Canby Utility

Molalla River below the filter backwash water discharge location LEA provided project management and environmental engineering services to Canby Utility (CU) for obtaining a new NPDES permit for their Water Treatment Plant (WTP) discharges to the Molalla River. Facility design implications resulting from the permitting were also addressed.

LEA worked with Canby and DEQ staff in developing the initial permit based on DEQ standard templates for NPDES permits pursuant to OAR 340-41 and 340-45.

LEA was involved in every facet of the NPDES permitting process including; data analysis, permit application, discharge requirements review, river water quality evaluation, discharge limits, draft permit development and review, public comment and final permit. Particular attention was paid to anti-degradation review requirements pursuant to OAR 340-41-026.

Data and information related to water quality impacts on threatened and endangered species was evaluated. Potentially affected agencies included US COE, Oregon DSL, NMFS, ODFW, USFW and others.

Project predesign elements included river infiltration gallery improvements, filter backwash water sedimentation ponds, de-chlorination and outfall diffuser. Alternatives evaluation was performed relative to design and cost-benefit analysis.
River infiltration gallery predesign



Hoodland WPCP Outfall Diffuser Project
For Water Environment Services, Clackamas County, Oregon

Sandy River site plan for outfall diffuser LEA provided environmental engineering services for completion of the Hoodland WPCP Outfall Diffuser Project.

LEA's Dave LaLiberte was the Project Manager and Engineer for the Hoodland WWTP Outfall project that included effluent treatment alternatives, outfall diffuser design and construction in an ecologically sensitive Sandy River corridor.

Effluent diffusers pre-assembled and ready for river installation

Challenges of the project were environmental permitting, public involvement process, diffuser design for rugged river section, mixing zone modeling, basin water quality evaluation, NPDES permit limit recommendations and negotiations, and facility alternatives and costs comparison.













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