Sediment Resources - http://www.arroyoseco.org/sedimentresources.htm

Here you will find tools to give your information and background to help you understand the issues related to sediment management and flood protection at Devil's Gate Dam in Hahamongna Watershed Park.


Devil's Gate Dam

Arroyo Seco Flood Timeline  History  Reservoir Map  Dam Elements

Devil's Gate Sediment History

Sediment Management

Sediment Analysis - 1980   US Forest Service 'It All Flows Downhill'

Philip Williams Sediment Study - 2000 Regional Board Denial - 2011 USGS Post-fire Assessment

New Paradigm (slides)   New Paradigm (video)  Sustainable Sediment Management for Hahamongna

CA Alluvial Fan Task Force  CA Coastal Sediment Workgroup   LA County Coastal Draft Sediment Plan

Why Hahamongna Is So Special

Pasadena's Hahamongna Master Plan Save Hahamongna

Habitat Wildlife News Wetland Plant Species found at Hahamongna

The Birds of Hahamongna

Ecosystem Assessments of Hahamongna Watershed Park

Habitat Assessment of Hahamongna 2012 Arroyo Seco Watershed Assessment - 2011

USACE Arroyo Seco Watershed Ecosystem Restoration Feasibility Study

County Environmental and Planning Documents

Draft Environmental Impact Report (October, 2013)

DEIR Alternatives

LA County Sediment Management Strategic Plan

EIR Notice of Preparation - Sept. 28, 2011 EIR Initial Study Project Description

Original Presentation – November 2010 Biological Survey Short Term Solution

Interim Measures Public Scoping Comments - November 2011

Public Comments on the County's Draft EIR

ASF Comments Audubon Society City of Pasadena

Friends of Hahamongna Sierra Club Other Comments

Pasadena's Position

Recommentations of Sediment Working Group  Sediment Working Group Slides

Final Environmental Impact Report - October 2014

Final EIR October 2014

No Big Lawsuit

No Big Dig Fact Sheet  Lawsuit Announced Video   What's Wrong with the Big Dig

Judge Chalfant's Decision - March 2017

Judgment Writ

Final EIR Revisions - July 24, 2017

Revisions Current Status Factsheet Contact Supervisors

Deadline for Comments on EIR Revisions — September 7, 2017

If you have any questions, please contact us at info@arroyoseco.org