At Riley, we carefully and purposefully select each team member to provide a diverse and complementary skillset that ensures the success of our clients’ goals. Our team is comprised of professional civil engineers, professional environmental engineers, professional hydrologists, and experienced technical staff.

We believe in customized approaches to meet each client’s unique needs. Our background in academic research allows us to personalize the plans we create and software we use to achieve our clients’ goals. Meet our team below—we’re looking forward to getting to know you!

Principal


Education:
•  Doctor of Philosophy in Civil Engineering, University of Arizona, 2017 (Water Resources Emphasis)
•  Master of Science in Civil Engineering, University of Arizona, 2011 (Water Resources Emphasis)
•  Bachelor of Science in Civil Engineering, University of Arizona, 2008

Licensure:
•  Professional Engineer Arizona (No. 54056)
•  Professional Engineer New Mexico (No. 26226)

Years of Experience: 13

Background:
Dr. Chee is the Founder and Principal of Riley. His experience as a water resource engineer is expansive and ranges from being a designer, to a project engineer/manager, as well as managing the company. He has experience in hydrology & hydraulics, water distribution systems, grading and drainage. As the Principal of Riley, he is responsible for managing day-to-day operations of the company and ensuring projects are technically sound and completed on time and on budget.

Dr. Chee grew up on the Navajo Nation where he experienced firsthand the socioeconomic challenges caused by the lack of basic water infrastructure. This motivated Dr. Chee to pursue the field of civil engineering to improve living conditions and ensure that society has the necessary civil and water infrastructure to facilitate economic well-being. Civil engineering is his passion, and he has made it his life’s mission to serve and help improve the lives of others. In working towards this, in 2017, Dr. Chee became the first member of the Navajo Nation to earn a Doctor of Philosophy in Civil Engineering.

Staff Engineer


Education:
•  Doctor of Philosophy (ABD) in Civil Engineering, University of Arizona, 2022 (Water Resources Emphasis)
•  Master of Science in Civil Engineering, University of Arizona, 2015 (Water Resources Emphasis)
•  Bachelor of Architecture, University of Arizona, 2003

Years of Experience: 11

Background:
Mr. Chris Horstman worked as a design/build architect focused on energy efficient and low-income housing until returning to the University of Arizona Civil & Architectural Engineering Department where he worked as a graduate student and research engineer. It was during this time that he joined Riley Engineering, having a shared commitment for developing water resources in rural and underserved communities. Chris leverages his knowledge of ground/surface water hydrology, hydraulic infrastructure design, and site civil design to provide creative solutions to large scale water resources projects. His construction experience has led Chris to become an asset at Riley for performing complex site grading and drafting comprehensive drainage plans. His expertise lies in employing his computer programming and modeling skills to provide creative solutions to large scale water resources projects.

Originally from Flagstaff, AZ, Mr. Horstman’s commitment to education and his community led him to help establish a K-12 water engineering competition. He remains active in this outreach program at Riley Engineering, helping students across Arizona understand their water supply through a hands-on engineering activity. Mr. Horstman’s graduate work has focused on surface and groundwater interactions along the San Pedro River in southeastern Arizona and northern Sonora, Mexico. In his role, Chris maintains a focus on quality client/stakeholder interactions, developed through his experience collaborating with regulatory government agencies, NGOs, and a diverse array of clients.

Business Manager


Education:

Bachelor of Science in Business Administration, Vanguard University of Southern California, 2014

Years of Experience: 10

Background:
Mrs. Selah Tsosie is the Business Manager at Riley, with a decade of combined experience in business administration, communications, public relations, marketing, training, events, and project management. She grew up in southwest Tucson, AZ, followed by living in southern California for 8 years. Family brought her back to Tucson, and she is thrilled to make a difference in the world as part of the Riley Engineering team.

Selah’s husband is Navajo, from Tuba City, AZ, on the Navajo Nation. She likes to say she’s “Navajo by marriage” and share the ways she’s fallen in love with the beauty of the Navajo culture as well as seen the barriers that many Diné encounter when trying to acquire essentials like running water and related civil engineering needs. Joining Riley Engineering was a dream come true for Selah, as she loves using her business experience to support our engineers while they support our clients.

Senior Engineer


Education:
Bachelor of Science in Physics, University of Arizona, 1968

Licensure:
•  Professional Engineer Arizona (No. 12481)
•  Professional Hydrologist – American Institute of Hydrology (No. 698)

Years of Experience:
49

Background:
Mr. Zeller was formally a Principal Water Resources Engineer with the surface water group of a nationally known engineering firm and served in that capacity for more than 30 years.  Mr. Zeller has been responsible for the administration of numerous water-resources projects in Tucson, Pima County, and the southern Arizona region.  His principal fields of expertise are arid and semi-arid hydrology, hydraulics, erosion and sedimentation, urban drainage and flood control, floodplain management, stormwater management (which includes water-quality aspects of stormwater runoff), flood hazard studies, and water resources development.

In his 49 years of professional experience, Mr. Zeller has served as Project Principal and/or Project Manager for well over one-thousand projects relating to hydrologic, hydraulic, and erosion and sedimentation problems within areas in and around Tucson, Pima County, and southern Arizona. Principal projects have included a river mechanics study for the Santa Cruz River in Tucson, project management of the Flood Control/Floodplain Management element of the Rillito Corridor Study, one of four principal elements of a $1.7 million dollar master plan study for a 110-square mile area in northern Tucson, development of a detention/retention design manual for use by both Pima County and the City of Tucson; development of a Floodplain and Drainage Standards Manual for the City of Tucson; development of scour procedures for pipeline crossings of watercourses for the Pima County Regional Wastewater and Reclamation Department; preparation of several river-management plans for major watercourses in Pima County and the City of Tucson; development of basin-management plans for the City of Tucson and Pima County; and the preparation of a master surface water plan for the City of Sierra Vista.  Mr. Zeller also authored the Pima County Hydrology Manual (currently referred to as “PC-HYDRO”) while employed as the Floodplain Manager of the Pima County Regional Flood Control District.

Staff Engineer


Education:

Bachelor of Science in Civil Engineering, University of Arizona, 2022

Years of Experience: 4

Background:
Jerod previously served as the business manager at Riley, bringing with him several years of administrative and business management experience. He also assists on design aspects for various water infrastructure projects while pursuing his Bachelor of Science degree in civil engineering from the University of Arizona with an emphasis in water resources engineering. In addition to water resources engineering, Jerod has a strong passion for infrastructure planning, where he aspires to help address civil infrastructure deficiencies in our state and on tribal lands, particularly the Navajo Nation. Jerod has the passion for water resources engineering and is excited to continue his education and gain more experience in the field.

Senior Designer


Education:

AAS in Architecture, Otero Junior College, 1972

Years of Experience: 28

Background:
Mr. Edmunds has a wealth of professional design and drafting experience for civil engineering projects ranging from land development and public works to mining.  He has worked on many projects throughout the southwestern United States. He is proficient in designing with AutoCAD Civil 3D. His experience includes preparation of: plats; grading and drainage plans; levee/berm design; channel design; paving plans; sewer and storm-drain plans; water plans; survey right-of-way plans; legal descriptions; roadway plans; waste-rock grading plans; heap-leach-pad grading plans, and reclamation contouring design drawings.

Staff Technician


Education:

•  Master of Science in Civil Engineering (Water Resources), 2023 (expected)
•  Bachelor of Science in Civil Engineering, Arizona State University, 2021

Years of Experience: 2

Background:
Christian started with Riley as an intern, and has been involved with design aspects on a variety of water infrastructure projects. Christian is passionate about helping improve the quality of living for people by improving civil infrastructure and promoting economic development. He believes that improvements to water infrastructure are essential for reducing poverty and sustaining economic growth. Christian eventually wants to help his people on the Navajo Nation by improving infrastructure after completing his master’s degree in civil engineering at the University of Arizona.