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General Services Agreement

DEA’s Experience and Qualifications

For more than 40 years, DEA has worked closely with clients to provide outstanding, award-winning project designs. Our environmental scientists are highly experienced in providing practical, innovative solutions to meet our clients environmental challenges. These services are augmented by a full complement of professional disciplines.

Environmental Specialties

Fish and Aquatic Biology

  • Fish and habitat surveys
  • Fluvial geomorphology
  • Stream channel form and function
  • Fish passage
  • Riparian restoration
  • Watershed and limiting factor analysis
  • Bioengineering
  • Monitoring

Wildlife Habitat/Biological Diversity

  • Threatened, endangered, and sensitive species surveys
  • Population viability analysis
  • Monitoring
  • Habitat mapping
  • Habitat restoration

Plant Ecology and Botany

  • Plant community analysis
  • Mapping and restoration plans
  • Integrated vegetation management
  • Sensitive, threatened, and endangered plant surveys and management strategies

Water Quality

  • Watershed analysis
  • Stormwater management
  • Wetlands creation
  • Wetlands treatment for water quality improvements

Environmental Documentation

  • Environmental assessments and impact statements
  • Biological Assessments

Landscape Design

  • Sustainable landscape design
  • Habitat restoration
  • Seed collection
  • Plant collection

Resource Economics

  • Habitat restoration value assessment
  • Economic assessment of environmental conditions
  • Return-on-Investment (ROI) analysis for ecosystem improvements

Our professionals are experienced helping federal agencies comply with environmental laws and regulations.

Laws and Regulations
  • Archaeological and Historic Preservation Act
  • Archaeological Resources Protection Act
  • Clean Air Act
  • Clean Water Act
  • Endangered Species Act
  • Executive Orders addressing wetlands, floodplains, farmland protection, and environmental justice
  • Fish and Wildlife Coordination Act
  • Migratory Bird Treaty Act
  • National Environmental Policy Act
  • National Historic Preservation Act
  • Native American Graves Protection and Repatriation Act
  • Pollution Prevention Act
  • Safe Drinking Water Act
  • State, regional, and local planning, zoning, and subdivision laws
  • U.S. Department of Transportation Act
  • U.S. Rivers and Harbors Act
DEA’s Federal Agency Clients
  • Bonneville Power Administration
  • Federal Aviation Administration
  • Federal Bureau of Prisons
  • Federal Highway Administration
  • General Services Administration
  • National Oceanic and Atmospheric Administration
  • National Park Service
  • U.S. Air Force
  • U.S. Army
  • U.S. Army Corps of Engineers
  • U.S. Bureau of Land Management
  • U.S. Bureau of Reclamation
  • U.S. Coast Guard
  • U.S. Department of Commerce
  • U.S. Department of Energy
  • U.S. Department of Housing
  • U.S. Department of Veterans Affairs
  • U.S. Environmental Protection Agency
  • U.S. Fish and Wildlife Service
  • U.S. Forest Service
  • U.S. Geological Survey
  • U.S. Marine Corps
  • U.S. Navy
  • U.S. Postal Service

Contracting with DEA

Steps for ordering services from DEA are outlined below. You may also review GSA’s Federal Supply Service Website at, which includes a section on ordering information.

Contracting Steps
  1. Develop a statement of work for one or more of the services provided by DEA under this contract. The statement should include, at a minimum, the work to be performed, the location of the work, the period of performance, a schedule of deliverables, applicable standards, and any special requirements needed to complete the work (such as security clearances, travel, special knowledge, specific equipment, models to be used for analysis, etc.).
  2. Develop a government cost estimate.
  3. Review available information from at least three contractors as allowed by Federal Acquisition Regulations (FAR 8.404), including price lists and qualifications information. This information is available through the GSA Advantage! online shopping service ( This review may be sufficient to meet the competition requirements for acquiring services (check with your local contracting staff). If further competition is desired, the scope can be forwarded to other consultants as described in step 4.
  4. Issue a request for cost quote to at least three of the consulting firms holding GSA Environmental Services contracts with the proper qualifications (a list of these firms can be reviewed at GSA eLibrary). This request should include the proposed scope (statement) of work, evaluation criteria, and an indication of whether you are seeking a firm-fixed price or labor hour level-of-effort cost quote for the services.
  5. Determine which contractor represents the best value. According to FAR, cost is to be considered, but you may also consider other relevant factors, such as special qualifications and past performance. Document your rationale for identifying the best value.
  6. Provide to your contracting office the material developed in the previous steps.
  7. Request final cost from “best value” firm. Your contracting office can then request the best value firm to submit a final firm-fixed price or labor hour level-of-effort cost quote for the requested services.
  8. Issue a task order. Following a negotiation of cost and services, if necessary, the contracting office can issue a task order directly with the contractor.

General Services Agreement

Key Contact

Craig Sheahan
Water Business Unit General Mgr.

Special Item Numbers

  • SIN 899-1: Environmental Planning Services
  • SIN 899-7: Geographic Information Systems

Contract Number: GS10F0216L

  • Geographic coverage: United States (including Alaska and Hawaii)
  • Maximum order:
    $1,000,000 (SIN 899-1)
    $1,000,000 (SIN 899-7)
  • Minimum order: $100
  • Prompt pay: Net 30 days
  • U.S. Government credit card accepted: Yes, not to exceed $10,000.00
  • Time of delivery: To be negotiated with contracting agency on each task order.
  • FOB: To be negotiated with contracting agency on each task order.
  • Business size: large

Ordering Address

David Evans and Associates, Inc.
Attn: Craig Sheahan
2100 S.W. River Parkway
Portland, OR 97201
Phone: 503-223-6663
Fax: 503-223-2701

Payment Address

David Evans and Associates, Inc.
Attn: Marcus McGarity
2100 S.W. River Parkway
Portland, OR 97201
Phone: 503-223-6663
Fax: 503-223-2701