Helton & Williamsen, P.C. is an engineering-consulting firm formed in 1993 specializing in water resource issues for agricultural, municipal, and industrial water users, state and federal agencies, and water conservancy and water conservation districts, primarily in Colorado. Particularly, Helton & Williamsen works with water rights issues involving the appropriation and adjudication of water rights, changes in water rights, plans for augmentation, water exchanges, reservoir operations, quantification of historical use, consumptive use, and return flows, surface water-ground water interactions, water rights appraisals, and expert testimony in surface water and ground water matters. Helton & Williamsen has worked in all the major river basins in Colorado and has long-term and on-going relationships with numerous clients throughout Colorado.
Staff
PRincipal
Thomas A. Williamsen, P.E.
One of the founders of the firm, Tom has over 40 years of professional engineering experience, including 7 years with the U.S. Bureau of Reclamation and the balance as a consulting engineer. He is familiar with the operation of the Bureau's projects in Colorado, Wyoming, Nebraska, and Kansas. In consulting, he has worked with clients for the development of water projects for municipal, agricultural, industrial, and recreational uses in all the major river basins in Colorado. Mr. Williamsen has engineered and assisted with the adjudication of several plans for augmentation in Colorado. He has advised clients about pending water right changes, offered expert opinions, and assisted counsel with negotiations for stipulated settlements. He has testified as an expert witness in Colorado district and water courts and other formal settings, and before the Special Master appointed by the U.S. Supreme Court in Kansas v. Colorado.
Education
University of Nebraska - B. S. Agricultural Engineering, 1973
University of Colorado Denver - Graduate studies in Civil Engineering
Societies
American Society of Agricultural Engineers
American Society of Agronomy
U.S. Committee on Irrigation and Drainage
Registration
Registered Professional Engineer in Colorado
PRINCIPAL
Daniel J. Gillham, P.E.
Dan joined Helton & Williamsen, P.C. in the spring of 2004 upon completing his master’s degree in Civil Engineering from Colorado State University. Mr. Gillham’s master’s degree involved research concerning the saline high water tables in the Lower Arkansas Valley. Mr. Gillham grew up on a cattle ranch and wheat farm in northeastern Colorado and has drawn upon this experience to assist him in interviewing ranchers and farmers to gather information on the historical use of irrigation water. Mr. Gillham performs and oversees water rights investigations and historical consumptive use analyses. He also performs water availability studies for new diversion and exchange water rights, assists in developing and operating plans for augmentation, and advises clients in their water use operations. He has also testified as an expert witness in Colorado water court and other formal settings.
Education
Colorado State University – B.S. Civil Engineering, 2001
Colorado State University – M.S. Civil Engineering, 2004
Societies
American Society of Civil Engineers. Member
Chi Epsilon, Member
Registration
Registered Professional Engineer in Colorado
Water Resources engineer
Tyler G. Hancock, E.I.T.
Tyler joined Helton & Williamsen, P.C. in 2021, after receiving his B.S. in environmental engineering from Rensselaer Polytechnic Institute in Troy, NY. He grew up in Eagle, Colorado and is familiar with the communities in the Eagle River, Gore Creek, and Colorado River basins. His work consists of investigating historical stream flows, diversions and use of water rights, calculating consumptive use and return flows from historical use of water rights, advising clients on management of their water resources, and maintaining accounting forms for river flows and for several clients’ water use.
Education
Rensselaer Polytechnic Institute – B.S. Environmental Engineering, 2021
Certifications
Certified Engineer in Training, Colorado
Water Resources engineer
Michael S. Simonson, E.I.T.
Mike joined Helton & Williamsen, P.C. in January 2024. He earned bachelor's and master’s degrees from the University of Colorado at Denver in Civil Engineering, emphasis in hydraulics and hydrology. His prior experience includes working as an intern with the Mile High Flood District in Denver, Colorado. He provides engineering support at Helton & Williamsen, P.C. including obtaining historical flow, diversion, and crop records; GIS mapping; preparing and running historical consumptive use models; and constructing and operating water rights accounting forms on behalf of various clients.
Certifications
Certified Engineer in Training, Colorado
Education
University of Colorado Denver – B.S. Civil Engineering, 2018
University of Colorado Denver – M.S. Civil Engineering, Hydraulics and Hydrology, 2023