The latest news and information about the District and Preserves.

Oljon Trail Construction

Work is wrapping up at El Corte de Madera Creek Preserve on a new section of the Oljon Trail that will connect to Springboard Trail. This new 1.3-mile multi-use segment through mixed redwood and tanoak forest creates a new perimeter trail that reduces the need for preserve visitors to access Highway 35 during their visit. As part of this project, crews will permanently remove the portion of the Steam Donkey trail that connects to Highway 35.  Approximately 0.6 miles of steep and poorly drained trail will be removed, including two culvert crossings across intermittent streams, and the area restored to natural habitat. The new trail segment is anticipated to open later this summer.

The project is the the final element of the El Corte de Madera Creek Watershed Protection Plan, designed to reduce sediment delivery to the watershed, and enhance the trail experience for preserve visitors. 

As part of the project, Midpen staff:

  • Constructed 6,050 linear feet of new trail;
  • Converted 800 linear feet of road to trail;
  • Restored 500 linear feet of old tractor roads
  • Installed two new bridges



Wildflowers in bloom on Midpen preserves.


Discover how to connect with your open space in our May Newsletter!

Temporary Public Access Closures

Due to ongoing maintenance and monitoring activities around the radar tower, the following areas at Mount Umunhum are temporarily closed:

  • The area surrounding the base of the radar tower and pathways leading to the area
  • The hiking only section of the Mount Umunhum Trail between the East Summit and Trailhead Shelter Area

The Mount Umunhum parking lot, trailhead shelter, stairs to the summit, west loop trail, summit shelter and trail to the Bald Mountain staging area all remain open.

Temporary Closure Area

In November 2017, small flakes of paint containing low levels of lead were discovered near the Mount Umunhum radar tower. Out of an abundance of caution for the safety of the public, the area surrounding the base of the radar tower and pathways leading to the area are temporarily closed to public access.

More Information

  • Rain and wind events in November 2017 appear to have caused small flakes of paint to shed off the radar tower. These paint chips were tested and found to contain low levels of lead.
  • Lead was a common additive used in paint before the 1980s throughout the country, when the former Almaden Air Force Station was active.
  • The former air force station site, including the radar tower, underwent comprehensive abatement and remediation work prior to the construction of the public access improvements.  This work included the removal of peeling paint from the radar tower and the application of a sealant.  Prior to opening to the public the tower was also painted with an anti-graffiti coating on the first floor.  However, it appears that the remnant lead-containing paint that originally was adhered to the structure is now flaking off.  For this reason, Midpen is taking the precaution of closing the area surrounding the radar tower to ensure the safety of the public visiting the summit area.
  • A subsequent project to re-assess the radar tower and identify any additional repairs, to seal and retain the structure over the longer term, will take place over the next couple of years.  There may be closures during this future work as well.

Mountain Lion Activity

Midpen Biologists believe that one or more mountain lions may live within and around Rancho San Antonio Open Space Preserve. While these lions are usually most active between dusk and dawn, sightings at Rancho San Antonio have been reported year round at all hours of the day.  Find out more about Mountain Lions and how to stay safe while out on the trails.

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Photo Contest

The Midpeninsula Regional Open Space District invites photographers to enter its 10th Annual Digital Photography Competition, running now through May 31, 2019.

We are seeking compelling digital images of nature, capturing the diversity of our open spaces.

Learn more