Hahamonga Monitoring

In November 2018, bulldozers from the Los Angeles County Department of Public Works began destroying riparian habitat in Hahamongna Watershed Park. To date, they have transformed nearly all of the 71 acres on the floor of the basin to bare dirt. Excavation of sediment will commence on April 15 and last through December 31, and this pattern will repeat for four years, the projected time required to remove 1.7 million cubic yards of sediment.

During and after this time, mitigation efforts will add native plants to areas surrounding the floor of the basin. But those activities will be dwarfed by the ongoing clearance of a 51-acre “maintenance yard” in the center of the basin, which will be scraped to bare dirt each fall.

These are tragic times for Hahamongna. But our reaction must be two-fold. First, we must act as watchdogs on the County’s activities. Already, they have bulldozed mature oak trees in the vicinity of the East Altadena drain – trees that were supposed to be protected under the project plan. The County has many other restrictions on their activities in Hahamongna, and those of us who spend time there must be aware of those restrictions and must report any violations. Read Part 1: General Terms of County Permits and Part 2: Specific Violations to watch for.

Second we must prepare for the time, five years ahead, when the major sediment clearing is complete. Riparian habitat grew in the basin before, and it will grow again, unless the County is successful in their plan to scrape bare 51 acres each fall. That will be the next battle, and Pasadena Audubon will need your help and support as we fight that battle.

For now, mourn for what we have lost, and prepare yourself to continue to fight.


Hahamonga before                         Hahamonga after

(photos from Carol Momsen)