MACARTHUR PARK
CHARTER SCHOOL
Create. Innovate. Belong.
Our Board
The Founding Board of MacArthur Park Charter School guides the vision, mission, and long-term success of our school. With expertise in education, finance, community development, and nonprofit leadership, our board is committed to creating a high-quality STEAM-focused public school that serves all students and families in Sonoma Valley.
Sarah Robertson
Chairperson of the Board
A native Sonoman, Sarah attended Montessori School of Sonoma, Prestwood, Altimira, and Sonoma Valley High before earning her degree in Communications from the University of Arizona. She holds a Master of Arts in Education with a focus on Elementary Teacher Education and a Multiple Subject California Teaching Credential, as well as Montessori Primary (3–6) certification. Her deep roots in Sonoma have shaped her lifelong passion for education and community engagement.
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Sarah began her teaching career in 2005 with the Oakland Unified School District, where she developed a strong foundation in diverse, inclusive education. She then spent nearly a decade teaching in the Hillsborough City School District, where she honed her instructional skills and leadership in curriculum development.
In 2016, Sarah returned home to Sonoma to join The Montessori School of Sonoma, founded in 1972 by her mother, Cathy Vaughn. Continuing her family’s legacy, Sarah is dedicated to nurturing curiosity, independence, and a love of learning in every child.
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Beyond the classroom, Sarah remains actively involved in her community. She has served on the Prestwood School Site Council since 2021 and joined the Sonoma Valley Unified School District Advisory Committee in 2024, contributing her voice to local educational planning and improvement efforts.
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In her free time, Sarah loves exploring new places and cultures and finds joy in discovering the world through shared experiences with her family. Traveling together allows them to learn, grow, and make lasting memories wherever they go.
David Arntz
Treasurer
Born and raised in Sonoma, David Arntz is a proud husband to Pilar and father of two children, Augie (6) and Heidi (3). A lifelong member of the Sonoma Valley community, David attended Montessori School of Sonoma, Prestwood Elementary, Altimira Middle School, and Sonoma Valley High School before earning his degree from Chico State.
As a Public Works General Contractor specializing in school construction, David has dedicated his career to building and improving educational facilities that serve students and families across the region. His deep appreciation for public education and his personal connection to Sonoma Valley schools inspire his commitment to ensuring local families have access to high-quality educational opportunities.
David believes every child deserves a supportive and inspiring learning environment. He is passionate about giving our community another great option for educating the youth of the valley.
Ty Durekas
Secretary
Mr. Ty Durekas is a father of three daughters who deeply cares about education and the Sonoma community.
Mr. Durekas is an experienced executive in the early education space with over 25 years experience. Over his career he has been an entrepreneur, corporate executive and a consultant. He has consulted for companies domestically and internationally.
Mr. Durekas currently is the CEO of Happy Hall Schools, a premier Bay Area Early Childhood organization. Prior to this position he served as Chief Executive Officer at Sonnets Academy in Chicago, Illinois. Sonnets is a high quality urban child care brand focused on creating child care opportunities for families in urban settings.
Before this he was Chief Executive Officer of Edleun Group (EDU) now known as Bright Path, a publicly traded early childhood company on the Toronto Stock Exchange, from June 2011 to June 2012. Prior to this, he served as Chief Executive Officer at Knowledge Universe, one of the largest private early childhood education (ECE) provider in the US, from April 2007 to June 2011. Here, Mr. Durekas had overall responsibility for more than $100M and employer sponsored child care business with clients located throughout the United States. He also served on the Executive Council for Knowledge Universe which sets strategic direction for all related business lines.
He was the founder of Children's Creative Learning Centers (CCLC) in Sunnyvale California. He served as the Chief Executive Officer of Children's Creative Learning Centers from 1992 to 2007, a business he subsequently sold to Knowledge Universe. CCLC operated preschools for clients like Stanford University, Cisco, Google, Electronic Arts, Oracle and Yahoo. During his time at CCLC Mr. Durekas co-founded On Care Services, a SaaS platform for clients in the early childhood education industry that purchase software to manage their preschools. While developing the CCLC organization, he spent ten years in various technology companies primarily with Applied Materials and Sony Corporation developing innovative product development initiatives, managing domestic and international marketing organizations
Kimberley Donohue Tinacci
Board Member
Kimberley Donohue Tinacci is an attorney employed by the State of California. Kimberley earned her law degree from Vanderbilt Law School in 2004, and graduated from American University in 1999 with a B.A. in Law and Society.
Kimberley began her legal career as a commercial litigator in Virginia before moving to California in 2006, where she continued that practice with a focus on securities litigation. In 2012, Kimberley shifted her practice to public service, and began working for the state, where she currently practices criminal appellate law.
Kimberley has been a member of the Sonoma community since 2018, where she lives with her husband and children. Her past and present community involvement includes membership in the California Lawyers Association (2006-present, member, Racial Justice Committee), California Women Lawyers (2019-present, member, Amicus Committee), Napa County Women Lawyers (2019-present, past Treasurer), Lawyers Club of San Diego (2015-2018, co-chair of the Reproductive Justice Committee), and as a volunteer attorney coach for the San Diego County Bar Association’s High School Mock Trial Competition (2013-2017).
Kimberley is excited to support MacArthur Park Charter School’s mission to provide the Sonoma Valley community access to a high-quality STEAM curriculum with an emphasis on equity, inclusion, and community involvement that will help build a foundation for our community’s youth to develop a lifelong love of learning.