Team isn’t just a word around here. It’s a commitment.

WSE’s people share strong values that include providing exceptional service to our clients as well as supporting our communities, employees, and their families. We always strive to do what’s right.

Meet the WSE team:


Jeff Johnson, M.S., P.E.

Jeff, co-founder of WSE, is an expert in the fields of hydraulics, sediment transport, and geomorphology, especially as they relate to public safety and natural resource protection.

Larry Karpack, M.S., P.E.

Larry, co-founder of WSE, is a problem solver who loves using his expertise in surface water hydrology and hydraulics to help clients address complex water management issues.

Bob Elliot, M.S., P.E.

With more than 30 years of practical experience modeling and investigating the many streams and floodplains within the greater Pacific Northwest, Bob specializes in and leads WSE's numerical hydraulic modeling program.

Chris Frei, M.S., P.E.

Chris is a senior hydraulic engineer with over 10 years of professional and academic experience working on complex hydraulic and water resource projects throughout the Pacific Northwest.

Dan Scott, PhD, L.G.

Dan is a fluvial geomorphologist who studies how wood, sediment, and water interact to shape river corridors.

Marissa Rohlfing, M.S., P.E.

Marissa has worked on hydraulic and hydrologic studies throughout the Pacific Northwest and beyond since 2015.

Colin Butler, P.E.

Colin joined WSE as a hydraulic engineer in September 2016 after completing his Bachelor's degree in Civil & Environmental Engineering with a focus in hydrology and hydrodynamics at the University of Washington.

Kaleb Madsen, M.S., P.E.

Kaleb joined WSE in the fall of 2017. He has a Master's in civil engineering from Washington State University.

Tim Tschetter, M.S., L.G., E.I.T.

Tim joined WSE in 2016. He is in the process of completing a Master's degree in Civil Engineering at the University of Alaska-Fairbanks with a focus on sediment transport and river mechanics.

Chris Meder, M.S., P.E.

Chris first joined WSE as an intern and returned in early 2020 as a junior hydraulic engineer after completing a Masters of Science in civil engineering focusing on hydrology and hydrodynamics at the University of Washington.

Sierra Smith, M.S., E.I.T.

Sierra joined WSE as a junior hydraulic engineer in the fall of 2023 and is excited to apply her knowledge and skills to hydraulic and sediment related challenges in the Pacific Northwest and beyond.

Ingrid Phillips, E.I.T

Ingrid joined WSE in the fall of 2023 as a junior hydraulic engineer. Ingrid completed her Bachelor’s degree in civil engineering with a focus on hydrology and hydraulics at the University of Washington.