Arroyo Seco News and Activities:  

Big Dreams for the Future of the Arroyo

What's the future of the Arroyo Seco? That's the question five Arroyolovers took on recently at the Pasadena Museum of Hisstory. And they had llots of ideas, visions and dreams that focused on protecting and enhancing the natural character of this great canyon. Sure, let's take out lots of cement and bring back the Steelhead too!

Check out the great coverage from Eddie Rivera in Pasadena Now.

Future? Let's Restore a Living River

Celebrating One Year Anniversary of No Fossil Fuels Mandate

photo credit: Brian Biery

"The march, organized by PASADENA 100, commemorated the unanimous passage of Pasadena City Council's Resolution 9977 exactly a year ago. The resolution declared a climate emergency and directed the publicly owned utility, Pasadena Water and Power, to plan for 100% carbon free electricity by 2030."

Read the whole story in Colorado Blvd

Send a Message to President Biden to Expand the San Gabriel Mountains National Monument

The Arroyo Seco, Tujunga Canyon and other parts of the Upper Los Angeles River Watershed Are Spectacular Gems of the Angeles National Forest and Belong in the National Monument

Take Action - Sign the Petition

This website is not affiliated with and has no connection to Arroyo Seco Foundation or Hahamongna Native Pleant Nursery. For that organization, please visit

New Report: Southern Steelhead Most Endangered on Pacific Coast

Rainbow Trout in the Arroyo

NOAA Fisheries Report  |   Southern Steelhead in Santa Barbara

Twelve eloquent women recently went to the Pasadena City Council to urge Pasadena Water and Power to end the use of fossil fuels for electric generation by 2030.

View the Urgent Appeal for Climate Action

Supreme Court Shrinks
the Clean Water Act

What's It Mean?

NPR  |   Washington Post

Native Plants Will Beautify Your Yard and Promote Biodiversity!

  • Bring California's unique beauty into your garden

  • Create habitat for butterflies, birds, and bees

  • Restore nature in the urban landscape

  • Support water conservation, garden without added fertilizers or pesticides, and even sequester carbon!

Ready to Ditch Your Lawn?

ThIs a Good Time to Start

Here's How to Do It

Step-by-Step Guide

Here is the Recap of the Los Angeles River and Arroyo Seco Fish Forum

View The Fish Forum

Streams Don't Belong in the Sewer


Sycamore Grove Park  |  North Branch

Sign the Petition

LA's Innovative Plan to Clean Up Streams:
Put Them in the Sewer

Poor Sycamore Grove Park! Once the park and its stream was the gem of Northeast Los Angeles. Now LA's going to put the "polluted" stream into the sewer to clean it up.

The Sad Story

Let the River Flow

Tim Brick Analyzes
What's Wrong with the Canyon Project

Pasadena Now

The Raymond Basin
Is Not a Bottomless Pit

It's been dropping for more than 100 years. How long can it last?

Learn More about the Groundwater Crisis

The Arroyo Seco Canyon Project

Will Degrade Hahamongna and Pump More Groundwater from a Depleted Basin

What You Need to Know

Falling groundwater, CEQA, trout, snakes, and hydrology . . . who could ask for anything more?

View the Show (2021)

Earth Day Special: Trout in the Arroyo Seco

Tim BrickSteve OlivasTom TomlinsonWendy Katagi 

Here's the Proof

Pasadena City Council Will Decide on Water Plan Soon | Take Action Now!Sign the Petition

The Cast

View the Premiere Presentation:

Have You Signed the Petition?

We believe the Arroyo Seco Canyon Project and Pasadena's 25-year Water Plan, the Water System and Resources Plan, will have detrimental impacts on the habitat, wildlife and water resources in Hahamongna and the Arroyo Seco.

We urge the City of Pasadena to protect the natural character of our region's greatest environmental treasure by:

  • using a living stream to capture storm flows and protect precious habitat;
  • ensuring an adequate environmental flow for fish and wildlife during the dry season; and
  • committing to a plan to stabilize and replenish the Raymond Groundwater Basin.

Sign Here

Let the River Flow

Heal the Raymond Basin

Arroyo Currents Explores Pasadena's Devastating 25-year Water Plan

News — Pasadena's zoning officer approved the final EIR for the Arroyo Seco Canyon Projects without considering ASF's and public comments. ASF, Pasadena Audubon Society and several concerned residents have appealed the decision, so it will be considered by the Zoning Appeals Board before it goes to the Pasadena City Council.

The Council will also be reviewing PWP's ill-conceived 25-year Water Plan in March. Stay tuned.

What's Wrong with PWP's Water Plan

How to Fix It

Pasadena's Water Crisis

Pasadena Water & Power has a $450 million program for the water future, but they are ignoring their unsustainable draining of the Arroyo Seco and local groundwater as well as the ominous impacts of climate change.

You don't miss your water till the well runs dry.

Learn the startling facts and what you can do —

Pasadena's Crisis

Here is the 11/18/2020 Arroyo Currents episode

Water Crisis

Pasadena Council to Consider Devastating Plan to Drain Local Water Resources

Does Hahamongna Really Need More Spreading Basins?

Pasadena Water & Power (PWP) is pushing ahead with an embarassing Environmental Impact Report (EIR) for the long-delayed Arroyo Seco Canyon Project (ASCP). The Pasadena City Council will consider the plan and the EIR in April.

We support water conservation, but projects like this must be done in a way that protects environmental resources. The ASCP plan features several elements that will degrade Arroyo Seco habitat and natural resources and thwart efforts to restore the Arroyo stream and native fish in the Arroyo.

  • Dam and Diversion Facilities

  • Six New Spreading Basins in Hahamongna Watershed Park.

  • Increased Pumping from the Depleted Raymond Groundwater Basin.


Get Involved. If you want to find out more, please send up here for updates.

It's Now Viewable Here For Your Entertainment and Edification:


Disappointing Plan Leaves Invasive Trees in Habitat Restoration Program in Lower Arroyo

View the City Council Discussion

November 18, 2020 —The Lower Arroyo Habitat Restoration Program is a good program, but not a great program, after Pasadena city officials caved into the entreaties of a small but noisy group of local residents who insisted on preserving exotic, invasive trees from the Canary Islands and Australia in the city's only designated nature preserve.

There was a wonderful response to the petition ASF circulated. It's clear that support for real habitat restoration is smart and broad-based.

Read the Remarkable Comments of Supporters  What's Wrong with Canary Island Pines

More on the Council Decision

The Van de Kamp Habitat Restoration Program in the Lower Arroyo

Official description: "This project provides habitat restoration within the vicinity of the Van de Kamp Bridge. The project will enhance, conserve, and restore the native plant community through the removal of non-native plant species and the planting of native trees and understory."

Learn More Take a Walk in the Lower Arroyo

Victory! Supervisors Approve Big Dig Settlement

July 7, 2020 — Today the Los Angeles County Board of Supervisors approved the settlement agreement with the Arroyo Seco Foundation and Pasadena Audubon Society regarding the County Flood Control District's sediment removal program behind Devil's Gate Dam in Hahamongna Watershed Park.

Supervisors' Agenda      Supervisors' Agenda Report

No Big Dig Lawsuit Factsheet

Big Dig Settlement - What's In it?

On July 9th ASF and Pasadena Audubon hosted an informative presentation and discussion on what's in the settlement and its implications for the future of Hahamongna.

Settlement Highlights

John Muir Remembers

Have you seen Tim Brick's dramatic monologue of the famed naturalist, "John Muir Remembers?" It's worth a look.

Arroyo Trails Open Again

Stay Safe! Stay Healthy!

It's been a long dry year and then a very wet winter in the upper Arroyo watershed, so we are anxious to get up there to do some trout scouting as the forest opens again. If you're interested in helping restore native trout to the Arroyo Seco, let us know!

Berkshire Creek

The Berkshire Creek Restoration in Hahamongna Watershed Park has now been completed. This is an Urban Streams Restoraton Program.

After a delay due to health precautions, the area is now open to the public again. We hope you will soon come to observe Berkshire Creek and how the project has improved habitat, flood protection and public safety in the southwest corner of Hahamongna Watershed Park.

All About Berkshire Creek

Welcome to Hahamongna Watershed Parking Lot

What kind of neighbor would destroy such precious streamzone habitat?

What kind of a city would let them?

Read the Full Story

Mayoral Candidates Square Off on Pasadena Environmental Issues

The Arroyo, climate change, the urban forest and other key environmental concerns were the focus of discussion at the Pasadena Central Libarary on Pasadena on Tuesday, January 14, 2020. The theme of the event was "How Green Should Pasadena Be?" The discussion surfaced significant differences among the candidates.

The Arroyo Needs You Now . . .

Support the Campaign to Protect and Restore a Natural Arroyo!

Cleaning Up the Arroyo Stream

More than 120 students from Maranatha High School came to the Arroyo Seco in Pasadena during Thanksgiving Week in November as part of volunteer program. The two-day event was part of Maranatha's annual Thanksgiving community service program. An energetic crew of students and teachers removed invasive species from the stream just north of the mouth of the Arroyo Seco as it comes out of the San Gabriel Mountains.

Out with the Invasives!

Berkshire Creek Restoration Nears Completion

The construction contractor has been making steady progress on the Berkshire Creek restoration in Hahamongna Watershed Park since they began in September. Construction is now expected to be completed by the middle of January, 2020.

Construction Pictures

A cute little endangered least bells vireo came to Hahamongna recently to celebrate the 20th anniversary of this Arroyo Seco website. Let's all celebrate by renewing our efforts to protect and preserve wildlife.

Judge's Tentative Decision Prompts Big Dig Settlement Discussions

Superior Court Judge Jemse Chalfant delivered a wake-up call to County officials on Wednesday, June 19. The mesage came in a strongly worded tentative judgment in favor of the Arroyo Seco Foundation and Pasadena Audubon in their second lawsuit against the County Flood Control District's Big Dig sediment removal program behind Devil's Gate Dam in Hahamongna Watershed Park.

"We won the first lawsuit and achieved some of our goals," said ASF's Tim Brick. "But the County failed to listen to the community or to detail a suitable mitigation plan, so we went to court again. This time we expect the County to listen."

There has been progress in the settlement negotiations. The next hearing date has been set for April 30th.

Never Forget the Importance of Hahamongna

We have never opposed the County Flood Control District's sediment removal from Hahamongna Watershed Park. We have been urging the Flood District to do a slow, steady sediment management program for more than thirty years. The County's irresponsible delay of their mainentance responsibility has necessitated the Big Dig and compounded its negative impacts.

We only sought a safe, careful plan, but as the trucks begin to rolll and the grinders and excavator dig deep into the Arroyo Seco streamzone, it is now apparent that the Flood Control District has failed on that score too.

We urge those who love Hahamongna to not forget its importance and to redouble your efforts to help restore it for future generations.

For the past year more than 400 community scientists have documented how biodiverse this 300-acre jewel of the Arroyo Seco is by making as many observations of as many species as possible before the County erases our memory of its grandeur.

You can help! Visit Hahamongna Watershed Park and take your photos of life in the Watershed.

Learn More About:


Located 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.

Learn and help others see why it's important to help Save the Hahamongna Watershed, a key hub of the Arroyo Seco, by documenting all wildlife, plants, trees, and recreation including people, dogs and horses located within the park boundaries.

Native Plants —
Can Beautify Your Yard!

Plants for Sale    |    Directions

Steelhead Used to Love the Arroyo

The Arroyo Seco is the most important stream on the Los Angeles River system for steelhead and trout because of its strategic location and fresh, cold water. Prior to 1920 steelhead migrated each year between the mountain watershed and the Pacific Ocean. Can you help bring them back home?

If you would like to get involved, send an email to

Native Trout in the Arroyo

Hahamongna Accountability Project Formed

Local residents and community organizations have formed a group of watchdogs to ensure that the County Flood Control District fully complies with all their responsibilities in implementation of their Big Dig project.

We need your help again to Save Hahamongna!

How You Can Help

Hahamongna Before -
Don't Forget

The River Returns

It's been so dry in the upper Arroyo Seco Watershed for so long that most people have forgotten the power of the river! The recent storms did a lot to change that! The stream gauge in the Arroyo jumped from 1 cubic foot (cfs) or 7.5 gallons per second to one thousand cfs briefly on January 17 and a week later climbed up to 300 cfs before resting for a bit at 100 cfs. That should really open up the stream up there between Oak Wilde and Switzer's Camp for the fish and aquatic species.

The Arroyo Is Under Attack

Click on the pictures for a bigger image

View the Devastation

County bulldozers have invaded Hahamongna Watershed Park this month to destroy the most valuable habitat in our region. The fifty acre destruction zone is the outline of the massive Big Pit they want to dig where they will destroy habitat each year.

2018 was the 25th anniversary of Hahamongna Watershed Park, so it's time to look back on the history of the park and the meaning of Hahamongna.

Come Visit Hahamongna ASAP!

Alternate Visions

The bulldozers and trucks are lined up ready to destroy the most precious habitat and wildlife corriror in the west San Gabriel Valley.

Trout Scouting in the Arroyo

Fisheries biologist Ken Jarrett from Stillwater Sciences took a crew of ASF volunteers up the canyon to assess conditions for native fish.

Brown Canyon Dam — Then and Now

Paul Ayers unearthed these pictures of Brown Canyon Dam three and a half miles up the Arroyo Seco Canyon from the mouth of the Arroyo near JPL.

Big Push to Include Arroyo in LA River Planning

"It's like an arm on a body," Tim Brick explains on KABC-TV.

Senator Portantino Moves to Include the Arroyo

Senator Anthony Portantino has introduced legislation to add representation for the Arroyo Seco in the Upper LA River and Tributaries Working Group.

Protecting Hahamongna: Big Dig Update

ASF and Pasadena Audubon are still working with Supervisor Barger and the County Department of Public Works to reduce the impacts of the Flood Control District's sediment removal program at Devil's Gate Dam. In November Supervisor Barger push through a motion to scale back the program in November. That was a big step, but there are still some unresolved problems with the Big Dig. We hope to have more news about the future of Hahamongna for you soon.

The battle to Save Hahamongna has been a long and bitterly fought one. Click on the link below to review the updates on the campaign against the Big Dig and witness citizen power in action.

Thank you for your support and congratulations!

Native Fish in the Arroyo — Can We Bring Them Back?

The answer, of course, is Yes! While there are numerous barriers and problems, the conditions in many parts of the Arroyo watershed are excellent for native fish including Rainbow Trout and Steelhead. ASF's meeting last July at the Pasadena Public Library generated a lot of interest and discussion about native fish.


One Arroyo

The Arroyo Advisory Group reported their progress to the Pasadena City Council on February 5th. The City Council approved $100,000 to establish a foundation that will raise funds for Arroyo Projects, such as a major trail improvement that will provide greater access and link together he various parts of the Arroyo in Pasadena.

Want to see a beautiful native plant garden? Check out the one this crew planted at Linda Vista Library, 281 Bryant St, Pasadena, CA 91103.

Arroyo River Parks
Restoring a Living River

Here's an innovative approach for the future that will restore the Arroyo Seco by integrating the river into the parks and the parks into the river.

Why Not a Complete San Gabriel Mountains National Monument?

Now that the Trump Administration review of National Monuments seems to be winding down, it's time to again raise an issue about our local 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 when the San Gabriel Mountains National Monument was announced. It's a shame because many of the most treasured and historic sites in the San Gabriel Mountains are contained in the territory that was not included.

Congresswoman Judy Chu has now proposed legislation that would expand the boundaries of the national monument to include all of the treasures of the Angeles National Forest.