Staff
The broadly-trained and accomplished staff at Balance has completed many projects together drawing on their intentionally diverse backgrounds and interests.

We pride ourselves at Balance in having a company culture that fosters a collegial work place and a commitment to our community. Some staff are active with non-profit groups or pursue their own research as a service to their communities. A number of these projects are multi-year or long-term efforts. - more info
Technical Staff
Barry Hecht, M.S., P.G., CEG, CHg, Senior Principal more info - email
Shawn Chartrand, M.S., P.G., CEG, Principal, Hydrologist/Geomorphologist more info - email
Edward Ballman, P.E., Principal, Civil Engineer/Hydrologist more info - email
David Shaw, M.L.A., P.G., Principal, Hydrologist/Geologist more info - email
Jonathan Owens, M.S.Eng., Principal, Hydrologist/Engineer more info - email
Mark Woyshner, M.S.Eng., Principal, Hydrogeologist/Hydrologist more info - email
Kealie Pretzlav, Ph.D., Senior Geomorphologist/Hydrologist more info
Dr. Pretzlav is a geomorphologist and hydrologist, with expertise in quantitative sediment transport, channel evolution/morphology, and flood hydrology. Her environmental and quantitative background is combined with data science experience to investigate restoration, flood control, groundwater, water quality, and climate change questions, often leveraging large datasets. Other experience includes sediment transport monitoring, bedload tracer studies, and flood flow monitoring. Dr. Pretzlav leads many of the large-scale climate change scenarios related to California's water supplies, which are linked to ecosystems and habitats, as well as groundwater and surface water availability.
• Ph.D., Geology; University of Texas at Austin
• B.A., Applied Mathematics; University of California, Berkeley
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Zan Rubin, Ph.D., Senior Geomorphologist/Hydrologist more info
Dr. Rubin uses his training in geomorphology, hydrology, and environmental design to investigate water quality, riparian and wetland restoration, and channel morphology. He addresses questions involving stream corridors, surface/ground water interaction and their effects on habitat, especially in alluvial corridors, mountain meadows, and near seasonal wetlands. Develops watershed assessment protocols and conducts watershed-scale planning. Quantifies the historical range of variability in ecosystem processes as a context for contemporary changes and to identify restoration goals. Dr. Rubin participates in most of Balance's sediment-transport and bed-conditions investigations for fish habitat in the San Francisquito basin and other watersheds in San Mateo, Santa Cruz, and Santa Clara Counties, as well as elsewhere in the Coast Ranges and central Sierra.
• Ph.D., Environmental Planning, University of California, Berkeley, 2015
• M.S., Geosciences, Fluvial Geomorphology, Colorado State University, Fort Collins, 2010
• B.A., Geology and Religious Studies, Bowdoin College, Brunswick, 2002
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Colleen Haraden, B.S., Geoscientist-GIS Analyst/Marketing Manager more info
Ms. Haraden is Balance's Marketing Manager, she brings to this position over 25 years experience in the geosciences, with a focus on GIS and data management for the water resources, environmental and public works fields. Her expertise varies from project management of technically rich projects such as, development of web applications and web portals for public outreach and program management, GIS for analysis and presentation ready graphics, data management of large groundwater monitoring programs. Ms. Haraden supports our clients with grant applications and strategies, she has prepared grant applications, managed grants (Prop 50 and 84), and managed grant funded projects. Colleen thrives on portraying complex concepts and communicating these ideas to the interested community members, developing outreach materials and helping to conduct public meetings.
• B.S. Geologic Sciences, San Diego State University
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Scott Brown, M.S., Geomorphologist/Hydrologist more info - email
Brian Hastings, M.S., P.G., Geomorphologist/Hydrologist more info
Brian Hastings has a diverse background in watershed, hydrogeologic and fluvial processes and water resource issues. Mr. Hastings is experienced in aerial photograph interpretation, geomorphic mapping, channel history investigations, stream gaging and sediment transport analysis. He combines these experiences for applications in stream and wetland restoration design and construction. Mr. Hastings has managed stream restoration projects with a focus on critical habitat for salmonids along the Central California Coast and Klamath Basin, Oregon. He has been a Balance Hydrologics team member for over 7 years.
• California Professional Geologist #8373
• M.S. Watershed Science, Colorado State University, Fort Collins, 2002
• B.S. Geology, Skidmore College, 1995
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Eric Riedner, P.E., Civil Engineer/Hydrologist more info - email
Denis Ruttenberg, P.E., M.S., B.S., Engineer/Hydrologist more info - email
Eric Donaldson, P.G., M.S., Geomorphologist/Hydrologist more info
Mr. Donaldson specializes in hillslope and fluvial geomorphology, and solves hydrologic problems of water-based ecosystems. He has 10 years of experience in collecting and analyzing topographic, hydrologic, and geomorphic data, for fluvial, estuarine, and coastal restoration projects using advanced surveying and remote-sensing instrumentation applied to GIS platforms. He measures flows of all types, sediment transport under storm conditions, instruments and interprets surface/groundwater interactions. Most of his work is for restoration planning and design, and to assess the success of constructed restoration projects. Other projects are related to flood protection or water rights. As a project manager, Mr. Donaldson strives to communicate complex and nuanced geomorphic and engineering concept in clear, meaningful terms so clients and community members can proceed with making decisions.
• California Professional Geologist #9209
• M.S. Geosciences, San Francisco State University, San Francisco, California, 2011
• B.A. Geology, Whitman College, Walla Walla, Washington, 2003
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Benjamin Roberts, P.E., Ph.D., Hydraulic Engineer more info - email
Peter Kulchawik, P.E.,M.S., Civil Engineer/Hydrologist more info
• Registered Civil Engineer in CA
• M.S. Civil Engineering, Colorado State University, Fort Collins, CO
• B.S. Civil Engineering, The Ohio State University, Columbus, OH
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Anna Nazarov, P.E., CFM, Civil Engineer/Hydrologist more info
Anna Nazarov is a licensed engineer specializing in one- and two-dimensional modeling of riverine systems, interior drainage systems, dam break inundation analyses, channel and wetland restoration design, floodplain analysis, channel hydraulics, watershed hydrology, and all associated fieldwork and data collection.
• Registered Civil Engineer in CA
• Certified Floodplain Manager
• B.S. Civil & Environmental Engineering, UCLA, 2007
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Teresa Garrison, P.E., M.S., Civil Engineer/Hydrologist more info
Teresa Garrison is a professional civil engineer with a focus on environmental engineering. Teresa specializes in water resources and water quality treatment with natural systems. Her previous projects in the water resources field include onsite water treatment systems (waste, grey, and drinking water), hydrologic and hydraulic modeling of surface runoff, natural treatment systems, stormwater pollution prevention and erosion control plans. Teresa's restoration projects including stream stabilization for architectural remains and habitat enhancement for the California Red Legged Frog. Civil site development and infrastructure skills include site development of roads, parking lots, and utility infrastructure, complete with AutoCAD plans and specifications. Teresa's work experience along with her continued education has given her a scientific background to understand water quality and natural treatment systems. She has a passion to learn new things, and apply her experience and expertise to provide innovative solutions to engineering design problems.
• California Registered Civil Engineer (No. 84034)
• M.S. Environmental Resources Engineering, Humboldt State University, Arcata, CA, 2011
• B.S. Civil and Environmental Engineering, Humboldt State University, Arcata, CA, 2009
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Anne Senter, M.Sc., Geomorphologist/Hydrologist more info
Ms. Senter specializes in watershed hydrology, fluvial geomorphology, and the geomorphic implications of large wood at all spatial and temporal scales. She assesses sediment sources in the field, models sediment and salt transport using conventional and custom software, simulates flood and baseflow hydrology, and designs stream and wetland restorations. Anne’s experience includes using advanced 2D hydrodynamic simulations in ArcGIS to develop site-specific solutions to evaluate project effects or to design restoration and channel-stability elements. She reviews modeling, both through field calibration -- often using high-water marks or customized remote sensing -- and through sensitivity analyses. Much of her modeling quantifies the stability of logjams and engineered log structures, as well as the fate-and-transport of large wood in channels.
• PhD. Cand., Watershed Hydrology specializing in Fluvial Geomorphology, UC Davis, expected 2012
• M.Sc., Watershed Hydrology specializing in Fluvial Geomorphology, UC Davis, 2008
• B.Sc., Environmental Studies, Earth System Science, San Francisco State University, 2005
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Gustavo Porras, B.S., Hydrologist/Geological Engineer more info - email
Krysia Skorko, M.S., Geomorphologist/Hydrologist more info
Krysia Skorko specializes in fluvial geomorphology, with 5 years of experience in hydrologic, hydraulic and geomorphic monitoring and data analysis. She has extensive field experience collecting flow and topographic data in rivers and streams, and experience analyzing these data quantitatively. She has applied these skills to land use management problems, such as assessing the affects of logging on salmon habitat and watershed health, predicting channel change in wetland environments, and investigating the geomorphic affects of invasive riparian vegetation. Most recently, she supervised groups of Americorps volunteers who are constructing erosion control and restoration structures in Sierra National Forest meadows.
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Jason Parke, B.S., Hydrologist/Geologist more info - email
Dana Jepsen, M.F.A., Hydrologic Technician more info
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Chelsea Neill, M.S., Geomorphologist/Hydrologist more info
Ms. Neill assists in the collection of streamflow and water quality data, including during storm events. She analyzes hydrologic, water quality, and suspended sediment data and prepares technical reports. Ms. Neill also conducts auto-level surveys and creates hydrologic models for stream restoration projects.
• M.S. Watershed Science, Applied Marine and Watershed Science Program, California State University Monterey Bay, 2015
• B.S. Geosciences, Denison University, 2009
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Montana Marshall, M.S., Engineer/Hydrologist more info
Montana Marshall specializes in quantitative field assessment and simulation of hydrologic conditions in streams, wetland, and tidal systems. She participates in a range of analyses directed primarily at habitat protection and enhancement, and in maintaining conformance with flood- and other hazard-protection regulations. She directs or assists in a variety of projects directed at maintaining or increasing infiltration and recharge in stream, dune, and floodplain systems.
• Engineer-In-Training, California
• M.S. Civil and Environmental Engineering, Environmental Fluid Mechanics and Hydrology, Stanford University, 2016
• B.S. Civil and Environmental Engineering, Water Resources and Hydrology, UCLA, 2014
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Benjamin Trustman, M.S., Assistant Hydrologist more info
Mr. Trustman specializes in mountain and watershed hydrology. He collects and analyzes streamflow and hydrologic data, including water quality and suspended sediment samples. He is experienced in remote sensor application and data logger programming, as well as analysis of hydrologic systems using both field monitoring and numeric modeling approaches. Mr. Trustman has conducted a variety of field investigations related to storm water quality and assists in planning and monitoring the success of ecological restoration projects.
• M.S. Hydrology, University of Nevada, Reno, 2015
• B.S. Ecohydrology, University of Nevada, Reno, 2013
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Lydia Yiu, B.S., Engineer/Hydrologist more info
• B.S., Civil and Environmental Engineering, University of California, Berkeley, 2015
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Carla Grandy, Ph.D., Hydrologist/Coastal Geomorphic Specialist more info
Interactions of humans and climate on coastal and fluvial systems including aspects of water quality, transport of contaminants and sediment, effects of land-use on sediment production, site-specific impacts of climate change and comparing permitted versus as-built design of coastal and estuarine structures. She leads Balance's quantification using GIS of historical geomorphic change based on archival data and remote sensing. Dr. Grandy also maintains a research interest in evolution of environmental policy and criteria for evaluating environmental justice. An associate professor of geology and oceanography at Skyline College (Redwood City), she has worked with Balance on a part-time basis since 2007.
• Ph.D., Earth Science, University of California, Santa Cruz, 2007
• M.S., Marine Resource Management, Oregon State University, Corvallis, 2000
• B.S., Environmental Earth Resources/Geography Minor, Texas Christian University, Ft. Worth, 1998
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Support Staff
Leslie Mack, Vice President of Operations more info
Leslie Mack has applied her background in Communications and Public Relations to effectively administer Balances broad business management needs while concurrently administering the firms benefits and personnel management strategies.
• B.A. Communications, Sonoma State University, 1997
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Rachel Boitano, Accounts Manager more info
Rachel Boitano has over 20 years experience in the bookkeeping field. At Balance she assists project managers with project coordination which includes contract and insurance administration, budget tracking and fiscal support.
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Magon Liu, Administrative Associate I more info
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