Eugene J. Riordan

Professional Experience

Partner Emeritus, Vranesh and Raisch LLP, Boulder, Colorado
January 2023 to Present
Partner, Vranesh and Raisch LLP, Boulder, Colorado
January 1986 to 1922
Attorney, Vranesh and Raisch LLP, Boulder, Colorado
October, 1981 to December, 1985

Mr. Riordan's practice focuses on environmental issues with an emphasis on solid and hazardous waste, water quality, and wetlands matters. In particular, he has:

  • Represented RCRA and Superfund clients in various hazardous waste matters including the development and negotiation of consent agreements and the preparation of permit applications.
  • Advised sellers and purchasers of real property, as well as environmental consultants, on environmental auditing and liability issues.
  • Negotiated agreements with the Corps of Engineers and the Environmental Protection Agency for dredge and fill permits and compensatory wetland mitigation.
  • Represented industrial clients in various air matters including APEN reporting, the preparation of air emission permit applications, and the development and negotiation of consent agreements.
Project Engineer, Psomas and Associates, Civil Engineers and Land Surveyors, Los Angeles, California
July, 1973 to August, 1976

While at Psomas and Associates, Mr. Riordan attained broad engineering and management experience with an emphasis in: (a) design of public and private improvement projects; (b) preparation of grading and site development plans; and (c) estimation of construction and engineering costs. Mr. Riordan is a licensed Professional Engineer in the states of California and Colorado.


Juris Doctor, 1981
University of Colorado School of Law, Boulder, Colorado
Law Review
Doctor of Philosophy, 1978
Civil Engineering -- Water Resources Planning and Management Colorado State University, Fort Collins, Colorado
Master of Science, Civil Engineering, 1975
California State University, Los Angeles, California
Bachelor of Science, Civil Engineering, 1971
Loyola Marymount University, Los Angeles, California

Professional Affiliations

Colorado Bar Association, Real Estate Law Section and Environmental Law Section
Boulder County Bar Association
American Society of Civil Engineers

Bar Admission

Mr. Riordan is admitted to practice law in the State of Colorado, the U.S. District Court for the District of Colorado, the Tenth Circuit Court of Appeals and the U.S. Supreme Court.

Present Awards

Best Lawyers in America 2008 - Present AV Preeminentâ„¢ Rating

Selected Publications and Presentations

  • "Colorado Wetlands" CLE International Conference, Co-Chair and Moderator, May, 2007 and 2008.
  • Iatridis, A.P., Riordan, E.J., Curran, R.W.: "EPA Overfiling after Harmon Industries, Inc. v. Browner," Colorado Lawyer, November 1999, Vol. 28, No. 11, p. 95; reprinted in American Bar Association's Environmental Transactions, Audits, and Brownfields Committee Newsletter, Vol. 2, No. 2, December 1999; and in Compliance Publishers' Colorado Compliance, November 30, 1999, pp. 15-21.
  • "Key Issues in Wetlands Regulation in Colorado," National Business Institute Seminar, Co-Presenter, August 1995.
  • "Environmental Law Issues," University of Colorado's Fourteenth Annual Hazardous Materials Symposium, Guest Speaker, December 1993.
  • "Wetlands Regulation," University of Denver Environmental Policy and Management Program, Guest Lecturer, October 1992.
  • "Financial Assurance Mechanisms for Closure and Post-Closure of Solid Waste Disposal Facilities," Governmental Refuse Collection and Disposal Association Conference, February 1989.
  • "Closure -- A Checklist for Survival," Waste Management Conference, Focus on the West, June 1987.
  • "Environmental Law and Risk Management," Hazardous Materials: Emergency Environmental Response Conference, June 1987.
  • "Federal Protection of Instream Flow Uses," American Society of Civil Engineers Annual Convention, October 1984.
  • Vranesh, G. and E.J. Riordan. Water for Synfuels Development: Problems in Acquisition and Development, 16 Nat. Res. Law 439 (1983).


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