Hahamongna is that rare spot in the Arroyo Seco at the foot of the San Gabriel Mountains where the mountainous watershed meets the urban plain. Periodically floods roar into this basin. Bounded on the north by the mountains and Jet Propulsion Laboratory and on the south by Devil's Gate Dam, Hahamongna contains five unique habitat zones that only exist in alluvial canyons near the mountains. Most sites like this in Southern California have been destroyed.

Don't let Hahamongna go the way of other lost environmental treasures in Southern California.


Witness the Winter Storms in Hahamongna

Winter 2009

December 2010 Storms


The Meaning of Hahamongna

The original settlers of the region were sometimes called the Hahamongna Indians. The word means "Flowing Waters, Fruitful Valley" in the native Tongva language.


July, 2010 - Council Eliminates One Soccer Field, Proceeds on Second

Council Action

Save Hahamongna is a campaign of the Arroyo Seco Foundation and other local organizations and concerned residents who are working to protect and preserve the nature of Hahamongna. We invite you to join us.

The Significance of Sediment EIR

County Supervisors on March 1, 2011 instructed County Public Works to conduct a full environmental impact report on the sediment management program at Devil's Gate Dam and Hahamongna in the Arroyo Seco.

Sups Approve EIR

Emergency Measures Completed

County crews completed the emergency measures at Devil's Gate Dam in late 2011.

Emergency Measures


View the Walkabout Videos Here

Hahamongna Walkabout 2012

Sign Up for Updates


View EIR Comments


EIR Toolkit


JPL Parking Lot To Go

JPL Parking


A New Paradigm for Sediment Management



Hahamongna Updates



More than 200,000 Trucks



La Cañada Alert

La Cañada

Dangers of Diesel

Diesel


A Strategy to Save Hahamongna

Strategy

The Trucks Are Coming! 50,000 a Year!

County Releases Devastating Hahamongna Sediment Trucking Plan

LA County Flood Control District has released their final environmental impact report on the sediment removal program for Devil's Gate Dam in Hahamongna Watershed Park. 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.

Three Public Meetings

Flood Control Announces Hahamongna EIR Meetings

LA County Flood Control District has announced that they will release the final Environmental Impact Report for the Devil's Gate Sediment Management Program in Hahamongna Watershed Park on October 20. A series of three public meetings will allow the public to comment on the Flood Control District's plan before it goes to the County Board of Supervisors for their review and possible approval.

  • Saturday, November 1, 2014, 1:30 p.m. – 3:00 p.m., John Muir High School Auditorium, 1905 Lincoln Avenue, Pasadena, CA 91104

  • Monday, November 3, 2014, 6:30 p.m. – 8:00 p.m., Jackson Elementary School Auditorium, 593 West Woodbury Road, Altadena, CA 91001

  • Thursday, November 6, 2014, 6:30 p.m. – 8:00 p.m., Descanso Gardens Maple Room, 1418 Descanso Drive, La Cañada Flintridge, CA 91011

Preliminary indications are that the Flood Control District will select one of their previous alternatives, making only minor concessions to Pasadena and the 250 commenters who raised concerns about the $70-100 million sediment trucking program.

Pasadena Council Adopts Sediment Recommendations

On Monday, May 12, the Pasadena City Council unaminously adopted the recommendations of the Devil's Gate Sediment Working Group. This group was established by Pasadena to develop a more sustainable alternative to those presented in the LA County Flood Control District's Draft Environmental Impact Report on the Devil's Gate Sediment Removal and Management Project.

The Sediment Working Group's recommendations, if adopted, would substantially reduce the scope and negative impacts of the Flood Control District's program, while protecting the neighborhoods and rare environmental values of Hahamongna Watershed Park and the Arroyo Seco.

Recommendations of the Sediment Working Group

Council Agenda Report

Sediment Working Group Slides

SGV Tribune Endorses Pasadena Plan

The DEIR Comments Are All In

See What People Had to Say

The Trucks are Coming!!!

200,000 double-bed, diesel belching monsters, clogging streets, creating noise, dust, pollution, destroying precious habitat and severely impacting our neighborhoods

County Unveils $100 Million Plan to Destroy Region's Most Valuable Habitat

Find Out What You Can Do  Key Meetings Coming Up

The Sustainable Plan for Hahamongna

Dessi Says: "Save the Habitat of Hahamongna!"

My name is Dessi Sieburth and I am 11 years old. I have been with Pasadena Audubon Society for 3 years. I like to watch birds especially in the Hahamagna watershed, and I have seen over 60 species of birds in Hahamagna. I am here to speak against the sediment removal project of LA county. If we remove the sediment the bird's habitat will be destroyed. An endangered species, the Bells Vireo was seen and might be nesting in Hahamagna. I saw rare birds at Hahamanga such as Indigo Bunting, Lewis's Woodpecker, and Vesper Sparrow. If we destroy the habitat these birds will not come back. Please save the Habitat of Hahamagna!

(signed) Dessi Sieburth

County Releases Horrendous Plan for Hahamongna

Get the facts on the County plan on this website and on this factsheet: Fact Sheet

Here is the County's news release on the Devil's Gate Sediment Removal and Management Plan: Official Notice

Pasadena Officials Move Soccer Field to Muir

Pasadena officials have now eliminated plans for an additional soccer field at Hahamongna Watershed Park and to instead dramatically upgrade a rundown softball field at nearby Muir High Schoolin Northwest Pasadena. This is a win/win for everyone involved, expanding recreational opportunity while protecting Hahamongna, and another victory for Hahamongna activists and organizations to preserve our region's most valuable natural area.

Conceptual Design Released for Arroyo Seco Canyon Project

The Final Conceptual Design Report for the Arroyo Seco Canyon Project is now available for public review! Thanks to all those who participated in the workshops and sent in comments. ASF, the City of Pasadena, and Carollo Engineers worked hard to incorporate public input as much as possible. The result, we hope, is a project that will not only integrate water resources, habitat, and recreation but will also satisfy the needs and desires of the community.

Please feel free to direct any questions, comments, or concerns to Jonathan Frame (jonathan@arroyoseco.org) and Gary Takara (gtakara@cityofpasadena.net).

Click on the Image

Arroyo Moonrise (in Hahamongna Park) Original 18 x 24 oil painting © 2012 Karen Winters. KarenWinters.com

EIR In Preparation

LA County Flood Control District is now considering what alternatives there are for their massive sediment removal and management program at Hahamongna. County staff expects to release a draft of their environmental impact report next Fall. We will keep you informed of developments, so check back here regularly or sign up for updates.

Hahamongna Updates

Threats to Hahamongna

It's the most precious enviromental zone in our region, but it's under attack again.

A massive sediment and habitat removal program of the County of Los Angeles threatens to strip the basin of its rare riparian and alluvial scrub habitat

Sediment

There's going to be a lot of action this year. We urge you to become informed about the issues and to get active to save this environmental treasure.

This site will keep you up to date on the latest developments in the campaign to preserve the natural richness of the area.