Calabazas Creek OSP Resource Management Plan

Protecting an ecological and cultural gem

In 2004, Ag + Open Space purchased a 1,285-acre ranch just north of Glen Ellen in order to establish the Calabazas Creek Open Space Preserve. Today, the preserve is managed to protect the diverse habitats, ecosystems and cultural resources there, and to ultimately to provide low-intensity public outdoor recreation.

The preserve stretches from the Valley of the Moon to the ridgeline of the southern Mayacama Mountains along the Napa-Sonoma county line and contains the entire Calabazas Creek watershed. Over the years, Ag + Open Space has offered docent-led outings led by partners and staff and coordinated a dedicated group of volunteer patrollers and various partners to implement a range of management activities, including erosion control, invasive plant management, and the removal of illegal marijuana grows.

The California State Coastal Conservancy, with the support of the Bay Area Ridge Trail Council, awarded a grant to assist in the development of a Public Access Plan, Management Plan, and an Operations and Maintenance Manual for the Preserve. Ag + Open Space finalized the first product of this grant – the Calabazas Creek Open Space Preserve Resource Management Plan – in 2016. The objectives of this Resource Management Plan are to:

  • Provide a comprehensive assessment of existing natural and cultural resources;
  • Identify natural and cultural resources in need of management and protection;
  • Present strategies for managing, enhancing and protecting sensitive resources and general ecosystem functions; and
  • Provide preliminary planning for future development of public access infrastructure in a manner that minimizes detrimental impacts to sensitive resources.

Public Access & Recreation

With Board direction, Ag + Open Space has been authorized to transfer the preserve to Sonoma County Regional Parks to manage and maintain the property, and to begin to develop a public access plan. The preserve boasts an important segment of the Bay Area Ridge Trail that will connect the communities on the Sonoma Valley floor with the Ridge Trail along the ridgeline of the southern Mayacamas Mountains. Ultimately, this plan will provide the public with an opportunity to hike, bike, and ride a sustainable trail along ridgelines that afford spectacular views of the San Francisco Bay Area, Mayacamas mountains, and Napa and Sonoma valleys.

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