Our Team

The people driving every success

Professional Credentials & Expertise

Our employees are highly trained and experienced professionals who are recognized leaders in their technical disciplines.

Our team includes licensed Professional Engineers (P.E.) and Professional Land Surveyors (PLS) registered in Colorado. These licenses require rigorous education, professional experience, and successful completion of state examinations. All engineering plans, specifications, reports, surveying plats, legal descriptions, and boundary work are prepared under the responsible charge of a Colorado-registered P.E. or PLS.

Our professionals also hold advanced certifications, including Certified Floodplain Manager (CFM), Professional Hydrologist (PH), Professional Traffic Operations Engineer (PTOE), LEED Accredited Professional (LEED AP), and Envision Sustainability Professional (ENV SP), along with advanced technical degrees, training, and specialized coursework.

DBC Ownership – From Left to Right: Cameron Knapp, PE, LEED AP (Lafayette) | Kate Varnum, PE (Colorado Springs) | Tim McConnell, PE (Colorado Springs) | Garrett Lingreen, PE (Lafayette) | Matt Selders, PLS (Lafayette)

Meet Our Leadership Team

The strength of Drexel Barrell is our people. Our multidisciplinary team combines technical expertise, practical experience, and a commitment to delivering exceptional results for every project.

Tim McConnell, PE

President, Colorado Springs

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Kim Cooper, CPA

CFO, Lafayette

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Cameron Knapp, PE

LEED AP, Lafayette

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Kate Varnum, PE

Principal, Colorado Springs

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Garrett Lingreen, PE

Principal, Lafayette

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Matt Selders, PLS

Principal, Lafayette

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Michelle Iblings, PE, CFM

Sr. Water Resources Engineer

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John Day, PLS

Survey Department Manager

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Gary Gremboweic, PE

Project Manager

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Mark Butler, DE

Principal Engineer

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Built on Experience. Driven by People.

For more than 77 years, Drexel Barrell has combined technical expertise, trusted relationships, and a commitment to quality project delivery. Learn more about the people and history behind our success.

Who We are →
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Tim McConnell, PE

President | Principal, Colorado Springs

Tim McConnell, PE, is the President of Drexel, Barrell & Co. (DBC) and has over 32 years’ experience. Tim is a highly-experienced engineer with an emphasis in site infrastructure design, roadway engineering and project management. He has extensive experience designing, managing, and securing approvals for a variety of private and public sector projects.

Kim Cooper, CPA

CFO, Lafayette

Kim Cooper is the CFO of Drexel, Barrell & Co. She comes with 36 years experience in Accounting where as 6 of those years are with Drexel, Bartell & Co. Kim has her Bachelors degree in Accounting and her Masters degree in Finance and Accounting. She fell in love with Accounting when she was in High School while taking an elective course in Accounting. She has worked in many different industries and has learned something from each one and taken it to her next opportunity. Kim enjoys camping, working and watching her grandkids play sports, goof off or just spend time with them and her family.

Cameron Knapp, PE

LEED AP, Lafayette

Cameron Knapp, PE, is a Principal at DBC with over 25 years’ experience in transportation, site infrastructure design, and drainage engineering. His experience includes site development, trails, street and highway plan and profiles, signing and striping, utility design, grading, drainage and erosion control engineering, storm water management plans, and storm water discharge permits.

Kate Varnum, PE

Principle, Colorado Springs

Kate Varnum, P.E. is a Principal at DBC with more than 22 years of experience delivering private and municipal infrastructure projects. Kate specializes in land development and site infrastructure design, with expertise in site development, utility design, grading, drainage and erosion control and stormwater management planning.

Garrett Lingreen, PE

Principle, Lafayette

Garrett Lingreen, PE, is a Principal at DBC and has over 23 years of experience specializing in roadway and utility design, Subsurface Utility Engineering (SUE), stormwater detention, drainage and grading, irrigation ditch projects, and contributing extensively to municipal projects as part of DBC’s engineering team.

Matt Selders, PLS

Principle, Lafayette

Matt Selders, PLS, is a Principal at DBC with over 44 years of vast surveying experience in Colorado. He prepares many different types of surveys including boundary, ALTA/NSPS land title, topographic, architectural, improvement survey plats, section breakdowns, mining claim, right-of-way acquisition, annexation, condominium mapping, and subdivision platting, legal descriptions, certifications, and subdivision dedications. Matt also oversees construction staking, utility locates, and as-built services for projects designed by DBC and others.

Michelle Iblings, PE, CFM

Sr. Water Resources Engineer

Michelle Iblings, PE, CFM, is our Sr. Water Resources Engineer with over 22 years of experience and leads our Water Resources Engineering department, specializing in floodplain modeling, management, mapping, permitting, and flood damage analysis. She has extensive experience in hydrology, hydraulics, erosion control, storm water management planning, and other types of drainage analysis and design, including stream restoration.

John Day, PLS

Survey Department Manager

John Day, PLS has over 47 extensive years of surveying experience in Colorado, New Mexico, Arizona, and New York, and has managed countless construction surveys, ALTA surveys, Right-of-Way research, analysis and determination on a wide variety of projects. He has also written countless legal descriptions for easements and Right-of Way. John currently manages multiple office and field staff out of our Colorado Springs office.

Gary Gremboweic, PE

Project Manager

Gary Gremboweic, PE, is a Project Manager at DBC with over 15 years of experience encompassing federally and non-federally funded roadways, multimodal, pedestrian access, pedestrian & drainage underpasses, and utility and storm drainage design projects, with a specialization in public utility infrastructure, Subsurface Utility Engineering (SUE), trails, roadway widening, mill & overlay, roadway rehabilitation, corridor master planning, and intersection improvements.

Mark Butler, DE

Principal Engineer

Mark Butler, DE, has over 40 years of engineering experience with an emphasis in infrastructure design and drainage engineering. He has designed numerous infrastructure projects that included all wet and dry utilities. These range from education, residential, government, and commercial to smaller utility replacement and improvement projects.