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 of 2009 in Hahamongna

Winter 2009 Storms

More Storms in December 2010

December 2010 Storms

Is this anyplace to put soccer fields?


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, Orders Staff to Proceed 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.



Devil's Gate 
 EIR Toolkit  


A New Paradigm for Sediment Management



Hahamongna Updates



The Trucks Are Coming




La Cañada Alert

La Cañada

Dangers of Diesel

Diesel


A Strategy to Save Hahamongna

Strategy



Second Annual Hahamongna Walkabout Rocks

As we promised, the Second Annual Hahamongna Walkabout on Saturday, March 31 was fun, educational and inspirational! Walkabouters who braved the torrential drizzle were treated to some pretty awesome presentations. But Jason Carman of PCC captured the highlights on video, so everyone can share in the magic of the Walkabout.

View the Walkabout Videos here:
Walkabout 2012

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

Emergency Measures Completed

County crews have now completed the emergency measures at Devil's Gate Dam. A mound of sediment and sand was moved from near the dam to the former Johnson Field on the west side of the Hahamongna basin. Some improvements were added to the dam and spillway to improve flood response.

These are the temporary measures approved by the County Supervisors in the Spring of 2011, while the Flood Control District prepares a more substantial sediment removal and management program.


The Significance of an EIR for Hahamongna

The Los Angeles County Supervisors on Tuesday, March 1, 2011 approved a motion instructing the County Department of 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.

This victory is the first step in ensuring that Hahamongna and its nature as well as the local neighborhoods are protected. A very important step in the right direction! We are sure that everyone, including the County, will come out winners from a better program that includes the evaluation of impacts and alternatives and fully involves the cities and stakeholders.

Congratulations to all involved.

Sups Approve EIR

Threats to Hahamongna

It's the most precious enviromental zone in our region, but it's under attack again. There's no question about it: 2011 will be a year of decision for Hahamongna.

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

Pasadena is forging ahead with an ill-conceived plan to add a parking lot and a soccer field to the center of the basin.

Soccer

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.