San Gabriels to the Sea:  How Hahamongna Fits In

<iframe width="840" height="470" src="" frameborder="0" allowfullscreen></iframe><!-- [et_pb_line_break_holder] -->

On February 19, 2015, Altadena Heritage hosted a public forum designed to put Hahamongna Watershed Park — and Los Angeles County’s controversial sediment-removal plan for Devil’s Gate Reservoir — into a larger context: its significance within the Arroyo Seco River System. Because of Hahamongna’s location between the sediment-producing San Gabriel mountains and the lower Arroyo Seco and Los Angeles River, which flows to the Pacific, it plays a vital role in the continued well-being of our most important local river system.

Three dynamic speakers helped attendees understand the geology, hydrology, history, and important role of this rich regional resource, and how the project as planned will impact the greater environment of Altadena, Pasadena and La Cañada Flintridge.


Dr. Dave Douglass is a geologist who earned his PhD at Dartmouth College and currently serves as a professor and Dean of the School of Science and Mathematics at Pasadena City College. Dr. Douglass sketched out the geological big picture that is often poorly understood or completely omitted from public discussions of large public works undertakings such as the Devil’s Gate Reservoir Sediment-Removal and Management Project.

Josephine Axt, Chief of the U.S. Army Corps of Engineers’ Planning Division, L.A. District, reported on the Arroyo Seco Watershed Ecosystem Restoration Study, which the Corps is conducting in partnership with the L.A. County Department of Public Works, a cost-sharing sponsor. The study’s purpose is to evaluate opportunities for restoring ecosystem function along the 11-mile reach of the Arroyo Seco, which extends from the Angeles National Forest border to approximately .05 miles from its confluence with the Los Angeles River.

Tim Brick is Executive Director of the Arroyo Seco Foundation and former chair of the Metropolitan Water District Board of Directors; he represented Pasadena on MWD’s board for 30 years. Mr. Brick filled us in on his foundation’s efforts to mitigate the current plan so that beyond protecting public safety, it also takes into account modern best practices of integrated resource management and taps opportunities to restore our region’s natural hydrology. Such an approach would benefit multiple users, communities, and the environment in and around Hahamongna Watershed Park.

The presentations were followed by a Q&A from the public.