Providing high-level results-oriented consulting.

Hours of Operation: Mon - Fri 8:00am - 8:00pm


Paul V. Rososco, P.E.

Mr. Rosasco has over 40 years of experience in providing supervision, management, and technical review for geological, hydrogeological, and engineering projects largely associated with solid and hazardous waste management. He has designed and implemented geological, hydrogeological and geophysical investigations and environmental monitoring programs for sites ranging from 0.5 acres to over 300 square miles. Mr. Rosasco has extensive project management and technical experience in a wide variety of waste disposal and environmental contamination projects. He has provided design, site engineering, and construction management services and acted as owner’s representative for surface and subsurface remediation projects. He has also been involved in a variety of geotechnical, geologic hazard, and water supply evaluation projects.

Mr. Rosasco has provided expert testimony related to groundwater occurrence, flow and chemical transport, the nature, extent and sources of environmental contamination, the necessity and appropriateness of various remedial actions, consistency of response actions with the National Contingency Plan (NCP) and other environmental regulations, and allocation of response costs. He has also provided expert assistance related to construction claims and disputes. He has provided expert testimony on the role of environmental issues and site remediation related to property valuation and condemnation proceedings. He has testified at numerous regulatory hearings and public meetings on issues ranging from site selection and the design and operations of waste disposal facilities, environmental contamination and remediation, and water quality standards.


M.E., Engineering Geology, Colorado School of Mines, 1985

B.S., Geology, University of Oregon, 1976 

Professional Engineer - Colorado, Washington, Illinois

Former Chairman, Vice-Chairman, and Member - Jefferson County, Colorado Planning Commission, 1994 – 2004

Timothy C. Shangraw, P.E.

Mr. Shangraw Mr. Shangraw has over 40 years of technical and management experience relevant to hazardous waste site investigations and remediation, water and wastewater treatment, mine dewatering, stormwater planning, and environmental studies. His expertise is particularly strong in managing complex remediation programs from conceptual design through detailed design, construction, and operations.


For the past 35 years, Mr. Shangraw has managed remedial design, remedial action, and O&M of the Lowry Landfill Superfund Site near Denver, Colorado. This has been a $100M+ project involving groundwater cutoff walls, pump and treatment systems, capping, waste pit remediation, landfill gas collection and treatment, and extensive environmental monitoring. Unique challenges included development and application of emerging technologies to oxidize and biodegrade 1,4-dioxane and other organic compounds and to sequester inorganic compounds. Such technologies involved both in-situ and above-ground treatment methods. Case studies were published in technical journals and/or presented to national technology-transfer organizations.


Throughout his career, Mr. Shangraw has managed and technically directed regulatory closures for Superfund, RCRA, TOSCA, and radioactive mixed-waste sites for Fortune 500 companies throughout the United States, for DOD sites, and for US DOE sites. He has also assisted clients with estimating present and future environmental liabilities for current assets and pending acquisitions and divestitures.


M.S., Civil/Environmental Engineering, University of Colorado, 1979

B.S., Civil Engineering, University of Massachusetts, 1977

Professional Engineer - Colorado

Board of Directors, Willowbrook Water and Sanitation District, 2008 - current

Bill A. Plaehn, P.E.

Bill has over 28 years’ experience in providing solutions to clients through project management, owner representation, construction management, construction at risk and technical direction for a diverse range of projects.   His background includes residential, municipal and commercial infrastructure, utilities, security systems, industrial wastewater, landfill gas, in-situ treatment, groundwater extraction, transmission, and treatment, and technology demonstrations.  Experience also includes site characterization, bench- and pilot-scale treatability testing, design and installation of remediation systems, system startup, operation and maintenance (O&M) support, civil construction, project controls, and cost estimating.

Recently as the Program Manager, Bill supported a client’s efforts to maintain and upgrade existing facilities and expand facilities domestically and internationally.  Program involves all aspects of project delivery including planning, site selection, design, procurement and construction.  Program includes the management of over 100 projects ranging in costs from $10,000 to $8,500,000.   Responsible for day-to-day safety, cost, schedule management, contract management and technical direction of design consultants, specialty subconsultants, and general contractors.

Bill managed the construction of $110M worth of infrastructure improvements for the City and County of Denver.  Work included subsurface utility work with over 10,000 LF of storm sewer installation, trenchless rehabilitation techniques including cured-in-place-pipe and waterline relocations.  Surface improvements included road widening, curb and gutter work, traffic signal installation, and irrigation/landscaping. 

Bill supported efforts to respond to the BP Mississippi Canyon 252 incident (Gulf oil spill in 2010).  Efforts include the deployment and management of near shore skimming operations and the Vessels of Opportunity (VOO) program.  Manage the deployment of over 2,000 vessels and 5,000 crew members across three states at over 25 marinas. 

In his career, Bill has worked as Project Manager, Project Engineer, and/or Technical Director for a number of environmental remediation projects including Lowry Landfill Superfund Site (Denver, Colorado), Perth Amboy Refinery (Perth Amboy, New Jersey), Buckley Air Force Base (Aurora, Colorado) and multiple Air Force technology demonstration projects.  


M.S., Environmental Engineering, Michigan State University, 1996

B.S., Civil Engineering, Purdue University, 1992

Professional Engineer - Colorado