COSCA: Preserving the Beauty of the Conejo Valley

A beautiful ring of green hillsides surrounds the valley in which we live. Although the valley floor is now covered with houses and businesses, at one time it was more like a savannah, characterized by grass, grazing livestock, and oak trees, with stream channels traversing it—particularly, the main Arroyo Conejo and its north and south branches. 

While the appearance of our area has changed significantly over the years, many acres of undeveloped hillsides and open space remain intact.  For that, we can thank the foresight of local citizens, large property owners, and community agencies. Today, a remarkable 40% of our city is dedicated to open space.

The Conejo Recreation and Park District was established in 1962, followed shortly by the incorporation of the City of Thousand Oaks in 1964. At the beginning of the City’s development process in the mid-1960s, our governing agencies envisioned a continuous “ring” of open space surrounding developed areas. The term “open space” was intended to mean any area “designated to preserve natural resources and open space character.”

In 1977, the City and the Park District created the Conejo Open Space Conservation Agency (COSCA) through a joint powers agreement to acquire more public land and manage it wisely. There are currently over 15,000 acres of public open space in the Conejo Valley. With most of the City now built out, COSCA is transitioning to emphasize open space management, resource protection, and public outreach.

COSCA is governed by a board of two City Council members, two Park District board members, and one member of the public. COSCA also receives assistance from local citizens and organizations: Residents assist with trail patrol and maintenance; and equestrian, bicycle, and hiking enthusiasts participate in an open space advisory committee.  Scouts and service-minded groups help with improvement projects, and the Conejo Open Space Foundation raises awareness and funding for special projects.

COSCA staff utilizes social media to inform the public about trail use and its possible dangers. With more residents turning to outdoor exercise and recreation, rangers have seen an increase in hiker and pet rescues as well as an increase in trash accumulation, graffiti, and dog waste. The guiding principle to follow is to “leave no trace behind.” 

Whether it be trailside or adjacent to private property, COSCA rangers and contracted vendors work tirelessly to help keep our community and open space resources safe. Extreme heat and wildfires throughout the state have awakened concern for wildfire safety and vegetation management on open space lands. Rangers work with the Ventura County Fire Department to ensure hazard abatement and fuel reduction are completed in a timely manner.

Recently, the COSCA Board approved expending funds from the Woolsey Fire Settlement for outreach programs, including fire safety. As COSCA transitions to a more active land-stewardship phase, the agency will focus on care and restoration of open space resources to fulfill the Agency’s mission statement: To acquire, conserve, and manage open space within and surrounding the Conejo Valley for future generations, sustainably balancing public use with ecosystem protection.

The City covers 56 square miles, 40% of which is dedicated open space. With this vast expanse of land permanently secured, it is up to us to protect our open space’s inherent resources and natural beauty to keep it intact for future generations. 

Doug Nickles is a Director/Board Member for the Conejo Recreation and Park District and the Conejo Open Space Conservation Agency. The views expressed are his and do not necessarily reflect those of the District, Agency, or the respective Boards. He can be contacted via email at

Photo Courtesy of L. R. Ames and Carol Venus

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