Natalie Sierra, P.E. – Project Manager
Natalie joins RMC with 11 years of experience as an engineer and project manager for the San Francisco Public Utilities Commission, as well as serving as a regulator and consulting engineer. Her technical area of expertise is biosolids management including resource recovery, biodiesel conversion, food waste digestion, biogas reuse, biosolids to energy projects, solar drying, and composting. In addition, Natalie has conducted process assessments of wastewater treatment technologies, sewer system master planning, regulatory management, and wastewater treatment plant capacity assessments. She has a master’s degree in environmental sciences and engineering from the University of North Carolina, Chapel Hill, and a bachelor’s degree in agricultural and biological engineering from Cornell University.

Nancy Sanchez – Administrative Assistant
Nancy has joined RMC’s San Francisco office as an administrative assistant. She recently graduated from San Francisco State University with a degree in accounting, and was previously an intern with RMC’s accounting department in Walnut Creek.

Susan Harris – Administrative Assistant
Susan has joined RMC’s San Jose office as an administrative assistant. She worked with RMC previously while serving as a project coordinator for the Santa Clara Valley Water District on the Coyote Watershed projects.

Catherine Tyrrell, LEED AP – Senior Project Manager
Catherine brings more than 32 years of experience to RMC’s Santa Monica office, specializing in stormwater management, watershed management, and water quality regulations. She is also a LEED Accredited Professional, with expertise in Low Impact Development and green infrastructure strategies. She was the Assistant Executive Director of the Los Angeles Regional Water Quality Control Board, and she has also served as the founding Executive Director of the Santa Monica Bay Restoration Project (now known as the Commission) and worked extensively with the City of Los Angeles Clean Rivers Through Effective Stakeholder-led TMDLs (CREST). With her depth of experience in both the public and private sectors, Catherine brings a keen understanding of the challenges and potential solutions to today’s stormwater and watershed management needs.

Christine Keltner – Accounting Manager
Christine Keltner has joined RMC’s Walnut Creek office managing the day-to-day supervision of the corporate accounting staff. She is a Certified Public Accountant (CPA) with experience auditing financial statements of many medium-size firms. Prior to public accounting, Christine worked for Wells Fargo in a supervisory position.

Melek Totah – Chief Financial Officer
Melek Totah is responsible for RMC’s mid to long term strategic planning and financial analysis, identification and implementation of operational improvements, budgeting and forecasting, and stock and acquisition analysis. Based in San Francisco, she has worked in finance for many large companies over the past 20 years, including the Coca-Cola Company, the Gillette Company, Microsoft Corporation and Gap, Inc. Most recently, Melek worked as CFO for WestCoast Children's Clinic in Oakland where she managed the organization’s funding sources, project assignments, budget/schedule compliance and overall financial performance. Melek received an MBA from the Thunderbird School of Global Management.