GHA’s Leadership brings together the right education, the right experience, and proven, consistently high performance as a leader.

It takes something special to be a GHA leader. That something is found in abundance throughout our leadership. With a collective belief that guiding clients’ projects to their best conclusions is a privilege, they help drive the entire GHA team towards consistently delivering at the high level our clients have come to trust.

Arthur Penn, PE, is not only a four-time champion of GHA's highly competitive chili cook-off, but also the President and COO of GHA. With more than 20 years of dedicated service to GHA, Arthur's leadership and expertise have been instrumental in driving GHA's growth and success. Arthur brings his passion for finding the perfect blend to his role at GHA. His ability to combine industry knowledge, strategic vision, and management skills ensures GHA's continued excellence and positions the company as a frontrunner in the industry.

Arthur Penn, P.E.


Dave Marquardt leads GHA's Construction and Survey department with confidence and innovation, bringing with him 25 years of hands-on experience. Dave is not only an accomplished professional but also an avid Rolling Stones fan. Having attended over 20 concerts in six different states, he has immersed himself in the energy and music of the legendary band. This passion for the Rolling Stones is reflected in Dave's work at GHA, where he combines his appreciation for artistry and precision to deliver exceptional results on every project.

David Marquardt


Donald E. Dixon, P.E., Principal, has dedicated more than two decades to GHA. His entry into engineering was influenced by his father, a Utility Contractor in South Carolina, who introduced him to the intricacies of construction blueprints. This early exposure, combined with a desire for the "air-conditioned office" his father spoke of shaped Don’s professional journey. At GHA, his deep-rooted understanding shapes his methodical approach, ensuring each project is executed with precision and innovation.

Donald Dixon, P.E.


Donald Matthews, P.E., CFM, began his remarkable journey with GHA as a student intern in 1986, advancing to a full-time position in 1988, and now serves as Vice President and Principal. Don's expertise in site design and water resources management has helped GHA establish itself as an industry leader. In his free time, Don can often be found playing rat hockey with his buddies. The focus and dedication he demonstrates in the game are paralleled in his work at GHA, leading to innovative solutions that enhance our communities.

Donald Matthews, P.E., CFM


Greg Newton, GISP, brings more than 11 years of expertise to his role as the Director of Geospatial Services at GHA. Alongside his professional achievements, Greg has a hidden talent—he spent 3 years traveling the country as Ringo in a Beatles tribute production. His passion for geospatial services and his unique creative background blend seamlessly in his work. Greg’s extensive knowledge and experience in the field allow him to provide innovative solutions and valuable insights to our clients.

Gregory Newton, GISP


Jonathan Past, P.L.S., acquired his professional licensure in Land Surveying in July 1999. Serving as GHA's Senior Surveyor and Land Survey Services Manager, his attention to detail and wealth of experience have significantly elevated the company's land survey services. Outside the office, Jonathan has a lifelong involvement with Native American culture as a member of the Ho-Chunk Bear Clan and Heylushka society. This relationship to the land and its history adds an extra layer of significance to his work at GHA.

Jonathan Past, PLS


Leo Morand, P.E., Director of Municipal Services, began his journey at GHA as an intern before moving to a full-time position in 2002. His passion for motorsports, specifically NASCAR, mirrors the dynamic and fast-paced environment he manages at GHA. Just as a racecar driver navigates the twists and turns of a track, Leo guides the Municipal Services Division with finesse, ensuring that every project is handled with the highest integrity and attention to detail.

Leo Morand, P.E.


Lucas Deferville, Assistant Director of Construction & Survey Services at GHA, has been a valued team member since 2000. Starting as an intern in high school, Lucas has dedicated more than 18 years to GHA, becoming a full-time employee in 2005. Outside of work, Lucas is passionate about lawn care and gardening, meticulously tracking his lawn and plant care with an Excel spreadsheet. This attention to detail reflects the precision and care Lucas brings to his work at GHA.

Lucas Deferville


Mei Zhu, P.E., CFM, LEED AP, Director of Water Resources, has been an integral part of GHA for more than two decades. With master's degrees from both China and Louisiana State University, she's a respected leader in water resource engineering. Active in her local school district's Chinese community, Mei organizes annual events celebrating her heritage. Her personal travels, spanning 38 states and 30 national parks, parallel her professional journey: exploring new terrains and pioneering solutions for GHA.

Mei Zhu, P.E., CFM, LEED AP


As the Director of Facilities and Utilities Management, Michael Grinnell brings more than two decades of management experience in the public works sector to GHA. A skilled woodworker, Michael's dedication to this craft reflects the same commitment and precision he brings to his role at GHA. When he's not devising innovative solutions or immersed in a woodworking project, he's often found fishing with his grandkids, cherishing the simple joys of life.

Michael Grinnell


Michael Warner, P.E., CFM, joined GHA in January 2021, bringing with him 36 years of experience, including Executive Director of the Lake County Stormwater Management Commission. Outside of work, Michael's passion for skiing is a reflection of his approach to new challenges at GHA. Having skied at 47 resorts worldwide, he attacks the moguls with the same fearless enthusiasm he brings to his professional pursuits, demonstrating GHA's commitment to exceed industry standards.

Michael Warner, P.E., CFM


Todd Gordon, P.E., began his journey with GHA as a Municipal Engineer in January 2000 and has since risen to his current role as CEO. An avid basketball player with a lifelong love for the game, Todd's drive on the court mirrors his professional trajectory from Municipal Engineer to CEO. This passion has shaped his competitive nature and strategic thinking, leading GHA to continued success and recognition in the industry.

Todd Gordon, P.E.


Valerie Pawlak, CPA, has been a dedicated member of the GHA team for 13 years, contributing her expertise as the Director of Finance. Valerie is an avid adventurer with a passion for camping and backpacking. She has already conquered 280 of the 567 miles of the Colorado Trail, a testament to her love for exploration and the great outdoors. Valerie's commitment to precision and attention to detail shine through in her work, ensuring smooth financial operations and efficient administration at GHA.

Valerie Pawlak, CPA


Walter E. Graft, P.E., Principal, began his journey with GHA in 1989. Over the span of 34 years, Walter has played a pivotal role in shaping the engineering solutions at GHA, pushing the boundaries of innovation. Having set foot in 26 different countries, he aims to double that number in the next decade, a testament to his boundless curiosity and drive, qualities he mirrors in his professional contributions to GHA.

Walter Graft, P.E.