Pecos River Basin

Oil spill in cotton field near Carlsbad
On behalf of the New Mexico Interstate Stream Commission (Commission), ERO conducted Phase I Environmental Site Assessments on 73 properties totaling more than 13,000 acres in the Pecos River basin. The Commission was considering acquisition of land and water rights in the basin to comply with water delivery requirements set forth in a Compact with Texas.  ERO reviewed available records, made site visits, and interviewed property owners and local government officials to assess the condition of the properties and identify recognized environmental conditions.

Stapleton International Airport Redevelopment

New housing and old traffic control tower in Stapleton

ERO assisted several nationally recognized homebuilders with development activities at Denver’s former Stapleton International Airport; the largest urban infill project in the United States. As part of due diligence efforts, ERO performed numerous Phase I Environmental Site Assessments (ESAs) and Phase II Site Investigations. The Phase I ESAs were conducted according to ASTM E-1527, and included review of historical data and voluminous environmental records to assess historical airport operations and remediation efforts that might affect proposed residential development plans.

San Luis Valley

Sangre de Cristo Mountains and elk

ERO has conducted several dozen Phase I Environmental Site Assessments (ESAs) in the San Luis Valley in southwest Colorado on lands totaling nearly 20,000 acres.  The ESAs served to establish conservation easements to protect farmland from development and for several proposed solar power installations.

Prairie Waters Project

Used oil storage on a farm property

The Prairie Waters Project is a City of Aurora, Colorado, water supply project that includes a 34-mile pipeline, pumping stations, a new water purification plant, and a water campus.  ERO assisted the city and the engineering team by completing numerous Phase I and Phase II site investigations on agricultural properties and proposed rights-of-way for either acquisition or easement.  The site investigations were conducted on flexible schedules to accommodate varying property access and real estate transactions, and were completed in a timely manner so as not to delay the design progress. All investigations were completed to comply with ASTM Phase I and Phase II standards and guidelines.

Solvent Contaminated Ground Water Remediation

Backfilling source-area excavation pit

ERO managed the investigation and cleanup of a site with elevated concentrations of trichloroethane and dichloroethene (TCA and DCE).  The project included characterization of contaminated soil and ground water, delineation of contaminant plumes, and implementation of remedial measures.  Using ground water flow and capture zone models, ERO designed and installed a pump and treat system that removes volatile organic compounds with an air stripper and has effectively reduced TCA and DCE concentrations in downgradient wells to below Colorado Basic Ground Water Standards.

Chromium Remediation, Power Engineering Company

Chromium  plating tank

ERO characterized and is remediating chromium contamination in ground water and soil beneath and adjacent to an industrial plating facility.  Our environmental scientists have employed several innovative techniques, such as direct-push technology coupled with field analyses for hexavalent chromium to cost effectively delineate a chromium plume in the ground water; slant hole drilling to characterize the soil beneath the facility in areas that would otherwise be inaccessible; and creating a “geochemical barrier” to prevent off-site migration of dissolved hexavalent chromium.  ERO also used a technique for in situ treatment of highly contaminated soils in the source area, and is now implementing a long-term management plan for the site, with the goal of ending active remediation.

Former 14th Avenue Shell Station

Soil vapor extraction system installation

ERO conducted site characterization activities to determine the extent of soil and ground water petroleum hydrocarbon contamination at a leaking underground storage tank site in Durango, Colorado.  We designed and implemented a Corrective Action Plan consisting of a soil vapor extraction/air sparge remediation system, and are currently monitoring the remediation system to maximize removal of petroleum hydrocarbons from subsurface soils.  By continuing the long-term ground water monitoring program, we can gauge the effectiveness of remedial efforts by comparing contaminant trends based on reliable historical site data to provide a greater degree of certainty as to the remediation and ultimate closure of the site.

Vista Ridge Development

Golf course at former shooting range

From 850 acres of land with numerous environmental issues to hosting the 2004 Parade of Homes, this development in Erie, Colorado, has had a dramatic transformation.  ERO provided Vista Ridge Development Corp. and related entities with a wide range of environmental services over a five-year period, including:

  • Completion of Phase I Environmental Site Assessments on numerous parcels
  • Completion of a Voluntary Cleanup Plan and a subsequent Request for a No Action Determination for an 80-acre shooting range that had been in operation since the 1960s
  • Construction management services during the cleanup of the shooting range, using an innovative approach to render the lead-contaminated soils nonhazardous for disposal as solid waste
  • Natural resource assessments of all parcels

Denver Public Schools Bus Maintenance Underground Storage Tanks

Underground storage tank removal
ERO assisted Denver Public Schools with the closure of six underground storage tanks containing diesel, gasoline, motor oil, antifreeze, transmission fluid, and windshield washer fluid at a closed bus maintenance facility.

Underground Storage Tank Removals

Former Adams County bus facility underground storage tank removal

ERO has assisted the City of Thornton, Colorado, with the closure of numerous underground storage tank (UST) sites during the past 15 years.  The sites have included USTs for fleet fueling, emergency generators, and vehicle maintenance facilities.