Current Officers

These are the people currently working at CEMS.

Suzanne Gabriele
Suzanne GabrielePresident

Secondary Position: Committee Chair – Fall Conference

Current Employer: Geosyntec Consultants, Inc., 44 Union Blvd, Suite 620, Lakewood, CO 80228, (303) 790-1340

Suzanne Gabriele’s consulting practice focuses on environmental, health, safety (EHS) management for a variety of industries including mining, oil & gas, food processing, electrical utilities, manufacturing, health services, and municipal governments.

Having worked as a strategic advisor to private and public sector clients at both the corporate and operational levels, Suzanne has extensive experience helping clients manage risks and recognizing opportunities to improve EHS performance. Examples of Suzanne’s experience include managing numerous policy and management system development, implementation, and improvement projects including systems conforming to and certified under International Organization for Standardization (ISO) standards. Suzanne has also managed numerous projects where the U.S. Environmental Protection Agency (EPA) compliance-focused environmental management system standard is required. Suzanne’s practice also includes advising on operational management plans, and performance and compliance monitoring and auditing programs.

In addition, Suzanne has extensive knowledge of regulatory programs and the ways in which their regulations apply in the built world. Ms. Gabriele works with clients to design programs to manage obligation under these laws and also voluntary commitments relative to environmental, social, and governance (ESG). She directs and manages compliance audit programs and supports clients in identifying root cause and corrective actions for noncompliance.

To advance the state of the practice, Suzanne is the chair of Geosyntec’s Environmental Management Action Group Steering Committee and a mentor to mid-career practitioners within Geosyntec.

Suzanne relocated to Denver in 1992 from the New York metropolitan area with her husband with the intent of returning there in 3 – 5 years, but around 20 years in, they decided to stay. They’re nearly done raising three self-reliant, intelligent young women and enjoy travel, food, music, backpacking, and backcountry skiing as a family.

Glen Vallance
Glen VallanceVice President and Membership Committee Co-Chair

Secondary Position: IT Support

Current Employer: Principal / Environmental Services Manager, CGRS Inc., 1301 Academy Court, Ft. Collins, CO, 80524, (970)493-7780

Glen Vallance is a Principal and Environmental Services Manager at CGRS’s corporate headquarters in Fort Collins, Colorado. Glen is a Recognized Environmental Professional (REP) with over 18 years of professional environmental experience, and he currently specializes in site assessment and remediation. In addition to managing multiple CGRS divisions, his experiences encompass a variety of tasks, including surface water quality studies, petroleum storage tank consulting, Phase I and II ESA, soil and groundwater assessment, aquifer characterization, and regulatory compliance. Glen is a graduate of Colorado State University’s Natural Resources Department with a bachelor’s degree in Watershed Science.

Maggie Mandell, P.E.
Maggie Mandell, P.E.Past President

Secondary Position: Spring/Movie Night Committee

Current Employer: Environmental Engineer, Environmental Works, Inc., 2770 Industrial Ln, Broomfield, CO, 80020, (301)943-2830

Maggie Mandell is a registered Professional Engineer (PE) with more than 15 years of experience in environmental engineering and consulting. She began her career with a 7 year stint as a consultant with Booz Allen Hamilton, conducting environmental compliance audits and providing environmental management support to mostly DoD clients. She then transitioned to Potomac-Hudson Engineering, a small business engineering firm, followed by Versar (formerly J.M. Waller), where she supported dozens of EPA Superfund Site projects and was also co-chair of the Versar Sustainability Program.  Maggie joined Environmental Works, Inc. (EWI) in October 2019 and has been supporting a variety of environmental compliance and remediation projects.  Maggie recently became a certified FAA Part 107 drone pilot and looks forward to expanding EWI’s environmental services to include this technology.

Maggie earned a BSE in Civil & Environmental Engineering from Duke University and a MS in Environmental Engineering from Northwestern University. Originally from Bethesda, MD, she and her husband moved to Denver in 2013; they spend their free time taking advantage of all that beautiful Colorado has to offer… hiking, biking, and skiing… with their daughter, son, and furbaby.

John Fontana, CPG, CWD
John Fontana, CPG, CWDTreasurer

Current Employer:  Vista Geoscience LLC, 130 Capital Drive, Suite A, Golden, CO 80401, (303) 277-1694

John Fontana is a Certified Professional Geologist (CPG #11985), an NGWA Certified Well Driller (CWD #12270)), a licensed water well driller (NM, NE, UT, SD, OK, KS), and serves as President/CEO and owner of Vista GeoScience LLC, based in Golden, Colorado.  John oversees all business operations at Vista, including environmental drilling (Geoprobe®), injection remediation services, soil gas investigations, and High-Resolution Site Characterization (HRSC) and 3D data modeling services.  John pioneered and introduced many of these services in the Rocky Mountain region and has supervised many Triad type environmental site characterizations and remediation projects at major DOD, DOE, and commercial/industrial sites across the country.

John has served as co-chair on the CEMS Program Committee, and on the Board of Directors as a Director, President, Past President, and currently as Treasurer.  He also serves as a Board Member/Advisor on the Executive Committee for the Colorado Section of the American Institute of Professional Geologists (AIPG).  John is also a member of CGWA, CWWCA, NGWA, AAPG, AEG, RMAG, RMAEP, ITRC (IAP), SAME, and SWANA. He served on the EPA Scientific Advisory Board on the Impacts of Hydraulic Fracturing on Drinking Water, and has also provided expert testimony in the area of stray gas (methane) migration issues.  Most recently John served on the Interstate Regulatory Technical Council (ITRC) teams and assisting in writing two guidance documents;  Implementing Advanced Site Characterization Tools (2019, ASCT-1) and Optimizing Injection Strategies and In-Situ Remediation Performance (2020, OIS-ISRP-1 ).

John’s 40 years of experience includes: 35 years as a business owner/manager, well-site geologist, laboratory management, managing domestic and international geochemical exploration programs, environmental site investigations, geotechnical and environmental drilling technologies, in-situ remediation injection design and implementation, analysis of soil gas for trace natural gases or contaminants, forensic analysis including stable isotopes, environmental baseline studies, carbon sequestration monitoring, statistical data analysis, mapping and 3D data modeling to create conceptual site models from integrated data sets.

John earned his BS degree in Geology, Oceanography and Physics from Humboldt State University in 1981.  Originally from California, John and his wife moved to Colorado in 1981, and now live in the Ken-Caryl Valley area.  Empty nesters, they enjoy time with their daughter Christina and son David whenever possible.  John volunteered for several years as a Cub Master and Scout Master where he enjoyed backpacking, camping and canoeing in the Rocky Mountains while teaching leadership and outdoor skills to young men.  He enjoys skiing, boating, fishing, hiking, SCUBA diving, as well as the occasional Rockies game. 

You can link up with John at


President & CEO


130 Capital Drive, Suite A, Golden, Colorado 80401
Work Phone: 303-277-1694,

Karen Trantow Lim, P.G.
Karen Trantow Lim, P.G. Secretary

Current Employer: Program Manager, Environmental Compliance; CDH Consulting, LLC  303-501-3415


Karen Trantow Lim, P.G. is an environmental compliance program manager and senior geologist with 34 years of environmental consulting experience including due diligence audits, Phase I/II environmental site assessments, stormwater permits and plans, complex NPDES permitting, FRP/SPCC plans, SARA Title III Tier 2 and TRI reporting, hydrogeologic investigations, reclamation, pollution prevention and waste management, tank removals and remediation, comprehensive regulatory review and interpretation, and hazardous waste site investigations. Her clients operate nationwide, primarily in the oil&gas industry in Colorado, Louisiana, North Dakota, Texas, Utah, and Wyoming.  

Karen grew up in Santa Barbara, California and migrated out to Colorado after college and a semester abroad in Sweden.  She began her environmental consulting career in California, then worked for EnecoTech Inc here in Denver, primarily focused on underground storage tank assessments.  While her husband got his master’s degree in Pennsylvania, Karen worked for Versar and HLA in Philadelphia on army and air force facility assessments, large industrial client remediation and hydrogeologic assessments, due diligence projects and overall compliance efforts.  Returning to Denver, she had the opportunity to work for the oil&gas industry, focusing on environmental compliance for oilfield service companies, midstream and upstream oil&gas clients while at LT Environmental, Inc.  In 2021, Karen joined CDH Consulting to continue this pursuit.  She has a Bachelor of Science degree in Geology and is a registered Professional Geologist in Texas and Wyoming.  

Karen enjoys hiking and skiing in the Rocky Mountains along with any time spent with their son, who just graduated from CU Denver.  This past fall, she completed an 8-day bike and barge trip through Belgium and the Netherlands. And she’s a diehard Bronco fan! 

Board Members and Liaisons

Our board members and liaisons

Melissa Armstrong, P.E.
Melissa Armstrong, P.E.Board Member and Fall Conference Chairperson

Current Employer: Consultant, Integral Consulting, Inc., 4704 Harlan Street, Suite 690, Denver, CO 80212, (303)596-8093

Ms. Melissa Armstrong specializes in groundwater remediation, fate and transport of contaminants, and management of environmental remediation sites. She has worked on a wide range of challenging environmental remediation sites and litigation cases.

Ms. Armstrong has more than 15 years of environmental experience, including conceptual site model development, remedial design and planning, and management of a variety of large site investigations for various contaminants of concern including per- and polyfluoroalkyl substances (PFAS). Her project management experience includes organizing and writing reports, project planning, cost estimating, preparing proposals, invoicing, and managing staff. In addition, Ms. Armstrong has extensive experience as a supporting technical expert in a variety of litigation cases, including construction defect cases and environmental contaminant fate and transport cases.

Rachel Blomberg
Rachel BlombergBoard Member and Scholarship Committee Co-Chair

Current Employer: United States Army Corps of Engineers, Special Projects Branch, EPA/IIS Program, (720)418-9317

Rachel Blomberg is a registered professional engineer (P.E.) and serves as a Program Manager for the EPA/IIS Program, Special Projects Branch, of the United States Army Corps of Engineers.  She served as a hydrologist and project manager for the Colorado Department of Public Health and Environment (CDPHE) in the Hazardous Materials and Waste Management Division Remediation Program, and worked for the USGS in their Colorado Water Science Center before joining the State. Rachel’s primary duties range from asbestos mitigation to contaminated groundwater cleanup on active military bases and formerly used defense sites, but she primarily focuses on emerging contaminants through her PFAS response efforts at Colorado’s Air Force Bases and through her involvement in drafting new site specific groundwater standards.

Rachel earned a BS from Cornell University and a MS from Colorado School of Mines. Originally from Northern California, she has lived in NY, AK, ME, Denmark and finally Colorado. She spends much of her free time renovating her century old home in Denver. When she is not doing that, she is most likely hiking or cross country skiing with her American Bulldog, fishing, cooking a new recipe, or enjoying a local show or game night.

Tom Fox
Tom FoxBoard Member and Colorado Division of Oil and Public Safety - Liaison

Current Employer: Colorado Division of Oil and Public Safety,  633 17th Street, Suite 500, Denver, CO, 80202, (720)346-1885

Tom is an Environmental Protection Specialist with the Petroleum Program for the Colorado Division of Oil and Public Safety (OPS). He earned a BS in Earth Sciences from Millersville State College (PA) and an MS in Geology from Michigan State University. After four years as a petroleum exploration geologist with Atlantic Richfield (ARCO) in Denver, Tom transitioned to environmental consulting. His dominant focus has been petroleum assessment and remediation, varying from corner gas stations to refineries and (often remote) pipeline pumping stations. Miscellaneous work, no less interesting, has included landfills, Phase I ESAs, SPCC Plan preparation, and CVOC sites. Traveling to most of the states, and experiencing a variety of weather and regulatory climates, was a particularly fun and educational side benefit.

Tom joined OPS in 2007. His work at OPS has involved updating cost guidelines for reimbursement; supporting the introduction of electronic, standard format reports; and investigation into the efficacy of activated carbon injection in Colorado. By 2015, Tom began working with the Interstate Technology and Regulatory Council (ITRC) updating the LNAPL document released in 2018; Tom has participated in all of the webinars on this topic to date and also traveled to China in 2019 to present the ITRC classroom training. Most recently, Tom has assisted with OPS’ Recognized Environmental Professional (REP) program.

Peter Jaacks
Peter JaacksBoard Member

Current Employer: Burns Figa & Will, P.C., 6400 S. Fiddlers Green Circle, Suite 1000, Greenwood Village, CO, 80111, (303)796-2626

Peter graduated from the University of Colorado Law School in 2021. During law school, Peter participated in the Acequia Assistance Program, aiding agricultural communities in the San Luis Valley with water rights issues, and worked as a Notes and Comments editor on the Colorado Natural Resources, Energy, & Environmental Law Review.

Prior to law school, Peter worked in both the natural resources and outdoor industries, consulting with mining companies in Nevada and running a fly-fishing guide service in southwest Alaska.

Peter is from Denver, Colorado and spends his free time fly-fishing, backcountry skiing, and hunting.

Evan Singleton
Evan SingletonBoard Member

Current Employer: Spencer Fane LLP, 1700 Lincoln Street, Suite 2000, Denver, CO 80203, (720)760-2211

Evan is an attorney with Spencer Fane LLP.  Prior to that he was an attorney with Gablehouse Granberg, LLC. He assists clients on a wide range of environmental matters, including NEPA, clean air, clean water, and hazardous and solid waste.

Evan earned his law degree from the Sandra Day O’Connor College of Law at Arizona State University, where he was on the university’s Energy Policy Innovation Council (EPIC), a joint program between the law school and other grad programs focusing on law, engineering/science, sustainability, and public policy in the energy sector. Evan  also competed in the Inter-American Sustainable Development Moot Court Competition in Bogotá, Colombia in 2013 and presented on international environmental law at the UN Framework Convention on Climate Change conference in Bonn, Germany in the same year.

Michael Whelan
Michael WhelanBoard Member and Program Committee Chairperson

Secondary Position: Committee Member – Fall Conference

Current Employer: Principal Engineer, Anchor QEA, LLC, 12596 West Bayaud Ave., Suite 450, Lakewood, Colorado 80228, Direct (303) 952-4850, Mobile (760) 845-2983

As a leader for Anchor QEA’s work in the Rocky Mountain region and with numerous West Coast project involvements, Mr. Whelan has 23 years of experience specializing in dredging and civil earthwork design for lakes and shorelines, restoration of stream habitat, development of waterfront facilities, and upland and offshore environmental remediation. His career originated with a bachelor degree from Colorado School of Mines, supplemented by graduate studies in environmental and geotechnical engineering at Georgia Tech and MIT, respectively. Today, after multi-year stints in Seattle and San Diego, he has a strong understanding of regulatory, environmental, and permitting-related issues, frequently applied to multi-party mediation and legal deposition settings. He currently lives in Evergreen with his wife and has two sons, one at Mines and one finishing high school.

Mark Collar, P.G.
Mark Collar, P.G.CDHPE Liaison

Current Employer: CDPHE,4300 Cherry Creek Drive South, Denver, CO 80246, (303)692-3379

Mark Collar is a registered Professional Geologist in the states of California and Wyoming and a California Certified Hydrogeologist serving as a project manager at Colorado Department of Public Health and Environment (CDPHE), Hazardous Materials and Waste Management Division Remediation Program. At CDPHE, Mark provides regulatory oversight at RCRA-permitted Department of Defense and other federal facilities impacted by a wide range of contaminants. Prior to working for CDPHE, Mark was a project manager for an environmental consulting firm focused on site assessment, characterization, remediation, and various types of regulatory compliance work for industrial and commercial facilities across the nation.

Mark earned a master’s degree in hydrology from the Colorado School of Mines, and a bachelor’s degree in geology from the University of California Santa Barbara, California. Outside of work, Mark enjoys bicycling brewery tours with his wife and dog, climbing, whitewater rafting, motorcycle riding, skiing, and home improvement projects.


Administrative Assistant

Juliana Reid
Juliana ReidCEMS Administrative Assistant

Secondary Position: Website Administrator
Current Employer: Administrative Assistant, CO Environmental Management Society (CEMS), PO Box 2426, Evergreen, CO 80437-2426

Born in England to Italian and American parents, Juliana immigrated to the U.S. in 1972. She was raised in New Jersey and received a Bachelor of Science degree in Computer Science (with a minor in Philosophy) from Lehigh University in Bethlehem, Pennsylvania. After moving to Colorado in 1992, she and her husband Dave raised two children while enjoying all that the Centennial state has to offer. She enjoys skiing, movies, reading, author lectures, and travel. She is also enjoying being an empty nester.

Juliana has been happily employed by CEMS since September 2009.