Mount Umunhum Summit Project
(updated: 2/24/14)

Update | Goals/Objectives | Area Closures | Interim Action | Timeline | History | Video

The Mount Umunhum Summit project is an excellent reflection of Midpen's three-part mission statement: to preserve open space, to protect and restore the natural environment, and to provide opportunities for ecologically sensitive public enjoyment and education.

Bald Mountain Parking Lot

The new Bald Mountain Parking Area is now open to the public.
November, 2014

view of summit
The District purchased the property in 1986, preserving this spectacular area as open space. During the course of Midpen's restoration work on the mountain, Purple Martins (Progne subis)--birds long thought to be absent from the area--were discovered and the District began planning to protect the species by installing special nesting boxes designed to protect eggs and chicks. The final phase, to begin shortly, will create a destination that is accessible to and accommodates a broad range of user groups and introduces new visitors to open space.

A new 24-vehicle parking area near Bald Mountain is now open! The parking area currently provides parking for visitors seeking to hike to Bald Mountain. Later, the parking area will also serve users of the Mt. Umunhum Trail, which will become part of the Bay Area Ridge Trail. The Mt. Umunhum Trail  is expected to open for public use in spring 2017 as soon as possible following construction and once facilities at the summit have been completed.

Demolition is complete at Mount Umunhum.  All of the structures at the former Almaden Air Force Station on Mount Umunhum (except the radar tower) have been demolished, utilities and asphalt paving were removed, and 95% of the building materials were recycled.  As a part of the demolition work, slopes were re-contoured as much as possible to match the original ridges and swales that existed prior to construction of the Almaden Air Force Station. Erosion control measures were installed, and the site held up well during the latest rain events.

The installation of nesting boxes for rare purple martins by Midpen staff and volunteers was chronicled by - Preparing a Mountaintop to Welcome Back Birds and People.


Goals and Objectives
The primary goal of the Mount Umunhum Summit Project is to establish a visitor destination that balances public access, enjoyment, and education with environmental restoration. This aligns with two directives of the District's Mission: to protect and restore the natural environment, and to provide opportunities for ecologically sensitive public enjoyment and education. This goal will be achieved through the following:
  • Create a destination that is accessible to and accommodates a broad range of user groups and introduces new visitors to open space.
  • Remove or permanently cap physical hazards and restore the native landscape and habitat for wildlife as much as possible.
  • Provide minimal visitor amenities that complement and highlight the world-class views and open space experience.
  • Provide ample, rich, and diverse trail experiences for hikers, bicyclists, and equestrians.
  • Highlight the rich natural and cultural history of the site through self-discovery and focused interpretive and educational opportunities.

In the near term, providing public access to the summit of Mount Umunhum as soon as possible is a primary goal of this project. Once completed, visitors to the summit will find an ADA interpretive trail, information about the area’s rich natural and cultural history, and expansive views of the entire Bay Area, Monterey Bay, Santa Cruz, and the Sierra Nevada.

Draft Mount Umunhum Environmental Restoration and Public Access Plan

Closures in Sierra Azul Open Space Preserve

In order to protect public safety and guarantee security, some portions of Sierra Azul's Mount Umunhum area are closed until the site is fully remediated and secure public access can be established.

Please note that the Mount Umunhum and Mount Thayer areas, where remediation work is ongoing, are designated Hazardous Closed Areas. Anyone who trespasses into the area will be cited for a misdemeanor.

Areas that are adjacent to Mount Umunhum and Mount Thayer are declared Temporary Closed Areas. Trespassers will be cited for an infraction.

Please refer to the attached map for details.

Interim Action A for the Mount Umunhum Environmental Restoration and Public Access Project

The Board voted unanimously to keep the Mount Umunhum radar tower until October 2017 to allow time for supporters and proponents of retaining the radar tower to develop partnerships needed for long-term preservation; however, if no partnerships or additional funding are secured during this time frame, the Board may reconsider all the options based on future funding and staffing constraints. At the same time, the Board approved spending nearly $415,000 for near-term repairs to allow the public access to the exterior base for a period of five years following construction; these repairs are scheduled for completion in 2014.

Interim Action A: Near-term repair and
securing of structure while considering external partnerships

Please refer to the sidebar to the right for a complete listing of previous public meetings and their associated reports, documents, drawings, and cost analyses.

*Indicates Public Input Opportunity

Oct, 17 2017 Deadline for proponents of the tower to establish and develop partnerships, funding, and other resources to allow for implementation of Option 3, Retain and Seal (per Interim Action A).
Nov 2014 Bald Mountain Parking Area open to the public.
Feb 2014 Demolition of structures (except the radar tower) complete at the former Almaden Air Force Station.
Feb 2013
$1 million grant received from the California Coastal Conservancy. The grant will support project implementation and fund a majority of the construction costs for the Bald Mountain Parking Area, Mount Umunhum Trail, and visitor amenities at the summit.
Oct17 2012*
Public Hearing - the Board of Directors selected Interim Action A: Near-term repair and securing of structure while considering external partnerships.
Sep 2012*

Public Hearing - the Board of Directors reviewed public input received regarding the Mount Umunhum Project and approved a portion of the project

Jul 2012*
Community open house and board workshop - information presented on design opportunities and constraints, maintenance, and costs for all three radar tower design options.
Jun 2012*
Public Hearing - the Board of Directors certified the FEIR and approved demolition of all structures except the radar tower.
May 2012*
Release of Final Environmental Impact Report (FEIR) for public review.
Jan 2012*
Public Hearing - to provide comment on the environmental analysis.
Dec 2011*
Environmental Documents released for Public and Board of Directors Review.
Jul 2011*
The Army Corps of Engineers contractor completes hazardous materials remediation work.
Dec 2010*
Public Hearing - to Consider Recommendation for Public Access and CEQA Scoping Meeting.
Nov 2010*
Public Open House presents Recommended Vision for Public Access.
Sep 2010*
First Public Workshop to Present Project Themes.
May - Jul 2010*
Background Project Research and Stakeholder Meetings.


On July 20, 2011, KQED QUEST aired a television piece entitled Mount Umunhum: Return to the Summit.

In September 2010, Midpen created this visualization of how Mount Umunhum would look after hazardous materials were removed and demolition was complete, and a vision of the world class views that one day would be available for all to enjoy. In All of this work was completed in February 2014!


The former Almaden Air Force Station at Mount Umunhum, located near Los Gatos,
was acquired by the District and added to the Sierra Azul Open Space Preserve
in 1986. This high peak, with views as far as Monterey Bay, is special to the
military personnel and their families who were stationed there. Mount Umunhum is
also important to the Ohlone people as part of their creation belief. Current Santa
Clara Valley residents know Mount Umunhum as the intriguing location of the huge,
cement radar tower visible for miles. Federal funding allowed the District to clean up the site to allow restoration and public access to this spectacular local landmark.

For questions or comments regarding the Mount Umunhum Summit Project, please contact Meredith Manning, Acting Planning Manager, at 650-691-1200.

To receive project updates via email, please subscribe here.


  Additional Information

Press Release
April 24, 2014

Press Release
February 20, 2013

Press Release
October 19, 2012

Press Release
October 15, 2012

Board Meeting Agenda + Report
October 2012

Press Release
October 10, 2012

Press Release
September 20, 2012

Board Meeting Agenda + Report
September 2012

Press Release
September 17, 2012

Press Release
July 20, 2012

Letter of Support from Congressman Honda
July 18, 2012

July 18 Meeting Flyer
Board Meeting Agenda + Report
July 2012

Press Release
July 16, 2012

Board Meeting Agenda + Report
June 2012

Final Environmental Impact Report
May 2012

Draft Environmental Impact Report || Appendices (separate)
December 2011

Notice of Preparation
December 2010

Site Overview
Concept Plan
December 2010

Board Report
December 2010

Vision for Public Access: Oblique View
November 2010

District Preserves & Surrounding Lands
Sierra Azul OSP
Nearby Natural Resources
Viewshed: Mount Umunhum and Mount Thayer
September 2010

Sierra Azul Open Space Preserve

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