Arroyo Seco Foundation

The Acorns Are Dropping!

All across our region, the acorns have begun to drop. Short stubby Engelmann acorns or the more elongated acorns from the dense Coast Live Oak (quercus agrifolia).

We will be collecting acorns during autumn to propagate at the Hahamongna Nursery. If you would like to get involved, please contact

Learn More about the Stately Engelmann Oak

No Big Dig! Lawsuit Update

December 8, 2015 has now been set as the tentative date for the court hearing on the lawsuit regarding LA County Flood Control District's program to excavate 2.4 million cubic yards of sediment from behind Devil's Gate Dam in Hahamongna Watershed Park and to truck it to distant landfills. LA Superior Court Judge Luis Lavin will consider the lawsuit, filed by the Arroyo Seco Foundation and Pasadena Audubon Society last December to challenge the enormous impacts of the County's program on Hahamongna and the surrounding neighborhoods including west Pasadena.


Haha Lawsuit: What's It All About?

Here's the news briefing explaining the Hahamongna sediment lawsuit filed by the Arroyo Seco Foundation and the Pasadena Audubon Society against the Los Angeles County Flood Control District sediment mining and trucking operation from behind Devil's Gate Dam in Hahamongna Watershed Park. ASF's Tim Brick, Laura Garrett, Conservation Chair of PAS and attorney Mitchell Tsai are featured in the video explaining their concerns and the issues that will be contested in the No Big Dig lawsuit.

The Trucks Are Coming! 50,000 a Year!

County Releases Devastating Hahamongna Sediment Trucking Plan

LA County Flood Control District's sediment removal program for Devil's Gate Dam in Hahamongna Watershed Park is deeply flawed. It's an old-style mining and trucking operation with devastating impacts on the nature and character of Hahamongna Watershed Park and on the surrounding communities.

Arroyo Seco Canyon Project

The Canyon Project is an innovative program to improve water resources and environmental conditions in the Arroyo co-sponsored by the Arroyo Seco Foundation and Pasadena Water & Power Department.


Arroyo Seco Excised from San Gabriel Mountains National Monument

By a mysterious process that no one will explain, the Arroyo Seco and the southwest corner of the Angeles National Forest were eliminated at the last minute from the newly announced San Gabriel Mountains National Monument.


Introducing Stewards of Public Land

Pasadena Council Says Archers Only!

We were disappointed by the Pasadena City Council vote to cede a large portion of the Lower Arroyo Park to Pasadena Roving Archers and other archers in a vote early in the morning of February 3, 2015. After a five hour public hearing and discussion, the council split 5-3.

The archers loudly proclaimed that the new agreement is not for "exclusive use" because anyone can still walk near the archery range, but in the future all other users will be warned by signs and barriers not to stray into the large archery range because in the judgment of the City Council it is too unsafe to allow the public to enjoy the area. All non-archers will be restricted to the dry, barren path lined by a chain link fence near the flood channel. No one, however, goes to the Lower Arroyo to walk near the flood channel.

As a conservation organization, ASF's vision is for a restored Arroyo Seco River flowing through a nature preservation area. Archers can fit into that vision, if proper safety restrictions are applied and if the public, at least at some times, has access to one of the most beautiful spots in the urban Arroyo Seco.

ASF urges you to visit the Steward's website for more details.

Help Protect Arroyo Woodlands!

It's a little beetle that could have a devastating impact in the Arroyo Seco and in local communities. The polyphagous shot hole borer (PSHB) burrows into numerous tree species and spreads a poisonous fungus.

The Arroyo Seco Foundation is looking for dedicated volunteers to survey trees for PSHB infestation in Pasadena's Arroyo Seco parks. With your help, we can determine the extent of its local presence and stop it before it spreads to the rest of our woodlands.

Contact Scott Cher at (323) 405-7326 or to sign up!

Learn more about the polyphagous shot hole borer here.


Exceptional Drought Highlights Need for Water Conservation

Western U.S. Drought Map With "exceptional drought" declared in part of the state, the first ever zero allocation of water from the State Water Project, and numerous fires, we want to remind Southern Califorians that there are many ways that all of us can do our share to conserve water. It may be as small as fixing a leak or as large as installing a drought-tolerant garden.

Here's Something Real You Can Do About the Drought - Click Here: