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!


•  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

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

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.

Gwen Woods Riley Engineering PE 700x900 px

Water & Wastewater Engineer

•  Doctor of Philosophy in Environmental Engineering, University of Arizona, 2018
•  Master of Science in Environmental Engineering, University of Arizona, 2012
•  Bachelor of Science in Engineering, Colorado School of Mines, 2006
•  Bachelor of Science in Mathematics and Computer Science, Colorado School of Mines, 2006

•  Professional Engineer, Environmental AZ #73774

Dr. Woods has experience spanning many areas of water monitoring, plant design, and water resources planning, including physical, chemical, and biological testing of water; hydraulic modeling; cost estimation; sizing and layout of process equipment; scenario planning; and design optimization.

Throughout her career, Dr. Woods has served in numerous roles, including assistant site civil engineer for the Tucson Water Santa Cruz Water Production Facility, where she designed a reservoir overflow channel and oversaw development of site record drawings. She was also a project engineer for the Metro Water Herb Johnson Reservoir Expansion Conceptual Cost Estimate, where she produced planning-level cost estimates for an additional ground-level water storage reservoir to expand the capacity of the Herb Johnson Reservoir. She provided engineering support for various upgrades at the  Tucson Water TARP Water Treatment Plant, a 10.4 mgd facility using UV-peroxide AOP for the removal of 1,4-dioxane and TCE from groundwater. She rendered hydraulic modeling of the TARP well field in support of adding a new sediment removal system to clear gravel from the source water and also as part of the design for an additional remediation well. She helped design a new tank and booster pump station to convey treated water to the recycled water system and the Santa Cruz River.

In addition, Dr. Woods has teaching experience at the middle school, college, and adult education levels.

Site Civil Engineering

•  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

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.

Jaeho Shim

Drainage Engineering

• Doctor of Philosophy in Civil Engineering and Engineering Mechanics, University of Arizona, 2017
• Master of Science in Civil and Environmental Engineering, Yeungnam University, South Korea, 2010
• Bachelor of Science in Civil and Environmental Engineering, Yeungnam University, South Korea 2007

Dr. Shim specializes in drainage design, with a particular focus on the development of one- and two-dimensional hydrodynamic and sediment transport models. He has extensive experience in performing watershed-scale hydrologic and geomorphic assessments and is highly skilled in evaluating and implementing projects that require complex hydraulic and geomorphic solutions.

Throughout his career, he has dedicated himself to research in the field, focusing on gaining a mechanistic understanding of sediment transport and river morphology processes. Dr. Shim has worked with the U.S. Department of Defense on the watershed erosion and sediment assessment of Barry M. Goldwater Air Force Range West. He developed the surface monitoring system using a 3D camera for real-time surface erosion monitoring. He has conducted sediment transport analyses for Pima County Regional Flood Control District.

Dr. Shim has investigated the loss of watershed function as a result of channel down-cutting and erosion using GIS, for the Pima County Regional Flood Control District. He has also taught hydraulic structure design, fundamentals of fluid mechanics, and fluid mechanics laboratory at the university level. At Riley, Dr. Shim leads many of our drainage projects, and works closely with staff technicians on drainage designs.

Rosita Kelly Navajo Nation Riley Engineering

Engineering Staff

•  Master of Public Administration, Grand Canyon University, 2013 (Government and Policy Emphasis)
•  Bachelor of Science in Civil Engineering, Northern Arizona University (Environmental Emphasis), 2000

Licensure: 24-Hour OSHA HAZWOPER


Mrs. Kelly is based in Leupp, Arizona and is a key team member for Riley’s projects on or for the Navajo Nation. She coordinates field work on the Navajo Nation, reviews construction drawings and documentation, prepares technical memoranda and reports, translates Navajo-English documents and conversations, and uses her wide range of experience to advise on Navajo projects.

Mrs. Kelly has served communities throughout the United States, including extensive work on and near the Navajo Nation, in a variety of capacities. Most recently, as the Executive Director for the Navajo Election Administration, she supervised the Navajo Election Administration team members, conducted the 2022 primary and general elections, and partnered with the Navajo Nation Council, Legal Counsel, and Election Board.

Prior to that, Mrs. Kelly worked as Navajo Liaison for a large national engineering firm. She served as the Environmental Unit Leader for California Wildfires disaster recovery, Project Manager overseeing the evaluation and assessment of 64 mines, and community leader attending Chapter meetings and building relationships with Navajo government officials. Mrs. Kelly’s background also includes Human Resources executive leadership for Navajo Nation Judicial Branch and a variety of schools, as well as civil engineering staff for Navajo Nation Department of Water Resources.

Senior Drainage Engineer

Bachelor of Science in Physics, University of Arizona, 1968

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

Mr. Zeller was formerly 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.

woman smiling blue jacket brown hair black shirt

Business Manager


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

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 Black Mesa, 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 Designer


AAS in Architecture, Otero Junior College, 1972

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.

Civil Designer


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

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.

Brenda Cosentino smiling



•  AAS in Accounting, Pima Community College, 2021 (Bookkeeping Emphasis)

Mrs. Cosentino’s background is in administration and bookkeeping. She has employed these skills throughout her career at several local businesses including, medical, accounting and retail as well as non-profit leadership. She is happy to call Tucson her home for close to 30 years.