Staff who have joined HEC:

Christopher Grethen - Chris joined HEC in August 2024 as a Student Trainee and was converted to his permanent role as an IT Specialist upon graduation from UC Davis in September 2025 with a degree in Computer Science. Chris is involved in multiple IT, infrastructure, and software development efforts across the Center, and has led the creation of multiple new in-house tools that have helped streamline many routine tasks for HEC staff. He is also helping to modernize the HEC classroom and software development infrastructure, including both hardware and software assets.

Itzel Lira -  Itzel joined the HEC EXE team as a Management Analyst in September 2024. She served on a deployment from April 2025 to March 2026, returning to HEC in April 2026. Prior to her current role, Itzel worked as a Budget Analyst for the State Army Aviation Office (SAAO) for 1.5 years. She holds a Bachelor of Science in Human Development from UC Davis, and completed the ROTC program as a Finance Officer, where over the years she has had the opportunity to develop her knowledge in finance and budgeting. Within HEC, Itzel is responsible for contract organization and payments, time and attendance, awards, GPC purchases, and other tasks as required to support the team’s operations.

Jacob Marinas - Jacob joined HEC's Hydraulics Division in August 2024 as a Student Trainee and converted to his permanent role as a Computer Scientist in September 2025, completing his Computer Science degree at UC Davis. Jacob works on HEC-RAS 2025 software, working together with computer scientists and engineers at the Center to bring quality of life features, improve stability, and enhance modeling workflows. His work on editors for geometry, shapefiles, and post-processor instructions have enhanced HEC-RAS 2025 advanced meshing capabilities in delivering high quality hydraulic models faster. 

Siva Malladi - Siva joined HEC in a Financial Management Analyst position in May 2026. Before HEC, he worked at Mobile District as a Budget Analyst for Air Force, Military Programs and Project Management. Prior to that he was at Lower Monumental Dam in Walla Walla District where he was a Budget Analyst.  Siva has currently a total of four years experience with the U.S. Army Corps of Engineers (USACE).  He has a BS in Policy Analysis and Management from Cornell University, an MA in Banking and Finance from the University of Alabama, and an MBA in Sustainable Business from Maharishi International University (formerly Maharishi University of Management).

Melissa Mika, PE - Melissa was selected for the Hydrology & Statistics Division Chief position in July 2026. Prior to joining HEC in July 2023, Melissa started her career with USACE at the Sacramento District in July 2018. Melissa has a BS in Civil Engineering from Iowa State University and an MS in Civil Engineering from Virginia Tech. She oversees 10 staff with deep expertise in advanced hydrologic and statistical methods for rainfall-runoff simulation, flood frequency analysis, forecasting, and reservoir operations applications.  

Richard Nugent, PhD - Richard was selected for the Water Resource Systems Division Chief position in July 2025. He has been part of the HEC team since September 2020, and before that he worked at the New York District for one year, with a total of 7 years of USACE experience. Richard has a BS in Economics from The University of Illinois at Chicago and an MS and PhD in Economics from the City University of New York. He oversees 11 staff with a diverse set of expertise, including flood risk management, consequence analysis, ecosystems modeling, reservoir analysis and computer science.

Jet Peralta - Jet graduated from UC Davis in 2024 and joined the team as a full-time employee on August 2024. He works as a Computer Scientist on HEC-RAS 2025 and contributes features that help engineers get their work done faster and get the information they need. His contributions since joining include velocity particle tracing, charting API, UML diagrams, rendering API, gridded precipitation imports, and the GPU solver implementation.  

Jack Schonherr - Jack was converted from student trainee to a permanent role as Computer Scientist in September, 2025. Jack's primary focus is supporting the HEC-FDA team, and Jack contributes to the HEC-RAS and NSI teams. In his first year as a permanent computer scientist, Jack has delivered several enhancements and other development for HEC software, including user experience enhancements and life loss risk assessment capability in the upcoming release of HEC-FDA Version 2.1, vector symbology in the recent release of HEC-RAS 2025, and major progress toward the geospatial risk visualization research and development effort through which HEC-FDA will achieve full geospatial processing and visualization capability, leveraging HEC-RAS 2025 as a platform. 

Staff members who have retired:

Beth Faber, PhD, PE - Beth Faber joined the Hydrologic Engineering Center in 2000 and contributed significantly to many teams in risk analysis, hydrologic statistics, and reservoir operations over her career. In celebration of her impactful career, Beth was awarded with the Civilian Service Commendation Medal, signed by Major General Jason E. Kelly, Deputy Commanding General for Civil and Emergency Operations. Below is the citation on Beth's award. 

For 25 years of outstanding service at the HEC. Her achievements in advancing engineering methodology significantly strengthened the Nation’s knowledge and skill in water resources risk-informed decision-making. Specific advances include modern federal flood‑frequency standards, methodologies for Monte Carlo simulation, and early Forecast Informed Reservoir Operations at Folsom Dam. Dr. Faber also trained countless USACE staff with outstanding ability to break down complex concepts into relatable terms, elevating USACE expertise across several mission areas. Dr. Faber’s record of achievements, dedication to duty, and selfless service reflect great credit upon her, the USACE, and the US Army.

Chris Nygaard, PE – Chris joined HEC’s Hydraulics Division in February 2024 as a remote worker, transferring into HEC from Portland District.  He had 23 years of federal civilian service as a river engineering specialist in the Pacific Northwest prior to joining HEC.  Chris’s work experience spans a wide range of river related topics including FEMA NFIP development, sediment transport and fluvial geomorphology, flood risk assessment and planning, navigation, and ecosystem restoration.  Chris has a BS in Civil Engineering from Portland State University.  He is a registered professional engineer in the state of Oregon.

Mike Perryman - Mike retired from HEC in December of 2019 and quickly returned as a rehired annuitant through February 2026. With over 40 years of Federal Service, Mike is well known, valued, and respected across the USACE Water Management community. His calm and thoughtful input during discussions was one of the many qualities his team appreciated. Mike was pivotal in the development of many Corps Water Management System (CWMS) software tools, and many, many data acquisition, transformation, and visualization scripts used by USACE District staff have his fingerprints.