Mark Shotwell
Mark ShotwellExecutive Director
Mark Shotwell comes with over 25 years of experience working in housing, social services and health care services for homeless individuals. A certified addictions treatment counselor (CATC), Mark most recently served as Senior Program Specialist for the County of Alameda’s Behavioral Health Care Services Housing Services Office and Care Connect, as well as Alameda County’s Director of Health Care for the Homeless Program.
Simon Tiles
Simon TilesDirector of Operations & Community Development
Simón Tiles joined the Ritter Center in 2009. Originally from Venezuela, Simón has significant experience working with underserved communities, including day laborers in Marin as well as Latino students and their families at both Berkeley and San Rafael High Schools. He first joined the Ritter Center team as a project coordinator to help create an employment resource for day laborers and part-time workers. He then served as a case manager for 3 years before transitioning to his current role. Simón lives in Berkeley with his wife and 2 kids.
Colin McDonnell
Colin McDonnellCase Management Director
Colin McDonnell has been working at the agency since 2009. After moving to the Bay Area in 2008, he became involved with a non-profit that was doing outreach to help support social services for homeless populations in San Francisco. This sparked an interest in advocacy work with disenfranchised and vulnerable populations. Colin currently lives in Oakland with his wife, who practices family medicine at clinics in the East Bay. He enjoys exploring the abundance of open spaces in the Bay Area and working in his garden when he can find the time to do so.
Tess Barbach
Tess BarbachChief Medical Officer
Tess Barbach joined Ritter Center in August of 2017. She is a Bay Area native and a certified family nurse practitioner with a nursing background in women’s health, substance use and medication assisted treatment, and primary care for medically underserved and incarcerated patients. Tess loves working in the framework of the Ritter Center’s interprofessional community of client service providers and believes that health encompasses much more than just physical well-being. When Tess isn’t working she enjoys doing pottery, cooking, and hanging out at the beach with her fiancé and their dog.