Arroyo Seco Planning Documents

Below you will find information on different studies and plans related to the Arroyo Seco Watershed. For a historic overview of planning in the Arroyo Seco Watershed, see the Arroyo Planning Timeline.

The Los Angeles River Ecosystem Restoration Feasibility Study

This page contains the official documents of the Los Angeles River restoration program sponsored by the City of Los Angeles and the US Army Corps of Engineers and adopted by the LA City Council on June 29, 2016. A major element of the plan is a large habitat restoration program at the Arroyo Seco Confluence with the LA River.

Cornfields Arroyo Seco Specific Plan

This is the first river-friendly specific plan adopted by the City of Los Angeles. It was adopted by the Los Angeles City Council on July 2, 2014.

Southwest Hahamongna Preliminary Habitat (2012)

This habitat assessment of the critical southwest portion of Hahamongna Watershed Park was conducted by ASF staff and volunteers in 2012.

South Pasadena's Arroyo Seco Pedestrian and Bicycle Trail (In Development)

South Pasadena is currently moving forward on the extension of the Arroyo Seco bike trail, from the South Pasadena Nature Park to Stoney Drive. This design also presents a plan to link the new trail with the existing one in the Arroyo Seco channel.

Arroyo Seco Watershed Ecosystem Restoration Study Cover Arroyo Seco Watershed Ecosystem Restoration Study (2011)

This study was conducted by the US Army Corps of Engineers in coordination with the Los Angeles County Department of Public Works to evaluate opportunities for restoring ecosystem function along the Arroyo Seco River from the Angeles National Forest border to approximately 0.5 miles from its confluence with the Los Angeles River.

ASWA Cover Arroyo Seco Watershed Assessment (2011)

The Arroyo Seco Watershed Assessment has now been finalized. The plan, prepared by CDM for the Arroyo Seco Foundation, reviews key restoration projects in the watershed and identifies five major projects which constitute an Arroyo Seco Greenway.

Arroyo Seco Watershed
Management and Restoration Plan (2006)

This plan was put together by the Northeast Trees and evaluates potential for water quality improvements and watershed management techniques. The plan provides preliminary details for a variety of restoration projects.

USGS Confluence Park Study (2005)

This report identifies the most important geologic, hydrologic, and biologic issues related to the development of an urban park at the confluence of the Los Angeles River and Arroyo Seco and presents a set of proposed work tasks to address these issues.

Arroyo Seco Water Resources Issues (2004)

This report on water resources in the Arroyo Seco Watershed was a partnership between the Arroyo Seco Foundation and North East Trees as part of the CALFED Arroyo Seco Watershed Management Plan & Education Program.

Hahamongna Watershed Park Master Plan (2003)

The Hahamongna Watershed Park Master Plan illustrates a vision for the 300-acres of open space that extends from Devil's Gate Dam north and into the Arroyo Seco Canyon, on the northwestern edge of the city. The Hahamongna Watershed Park Master Plan was adopted to establish a visionary framework for recreation, water resources, flood management, habitat restoration and cultural resources in this area.

Pasadena Arroyo Seco Master EIR (2003)

This is Pasadena's long-awaited Arroyo Seco Master Plan with detailed concepts for the Lower Arroyo, Central Arroyo and Hahamongna along with special sections on the Rose Bowl and Arroyo Seco guidelines.

Arroyo Seco Watershed Reconnaissance Study (2002)

This study by the US Army Corps of Engineers established a federal interest in the Arroyo Seco Watershed.