Santa Anita Debris Basin received a significant amount of material from the December 2021 storms. Crews have removed over 50,000 cubic yards (CY) – for context, that’s basically removing a football field, 25 feet deep. The recent March storm brought in additional material and flooded the project site. Hauling operations is expected to take an additional 2 months to remove approximately 40-60,000 CY currently in the basin. With the unseasonably warm weather over the last week and forecasted to continue again next week, an additional street sweeper will be brought in to address dust. They stated that it is imperative to have the basin restored to its full capacity for the 2022-23 storm season to provide the necessary flood and debris protection for the residents of Arcadia, Monrovia, and other downstream cities. Concerning the Santa Anita Wash, the concrete overlay constructed over 35 years ago delaminated at several locations and temporarily reduced channel capacity during the December 2021 storms. The Wash is over 5 miles long. To reconstruct the overlay and mitigate potential for uncontrolled flows during future storm events, the County will remove the remaining overlay and reconstruct. To remove the overlay, heavy equipment in the channel will separate the slabs then haul (via the channel invert) to the middle sediment placement site for processing. A rock crusher will process the slabs into crushed rock for possible reuse in other construction projects. The removal project is expected to last 2 months. The majority of the work will be contained on site to minimize the impact to residents. Crushing the material will greatly reduce the amount of truck hauling on the roads as more material can be taken per truck load. It will also allow for the recycling of the material, which is better for the environment (the bad news is that crushing rocks can be noisy and dusty work – we will work with them on mitigating these issues). Once this work is done, County engineering staff will investigate the invert and complete the reconstruction design plans.

Residents may be directed to Mr. Ryan Romo, County Civil Engineer, to address concerns or questions they have related to the above. He is reachable by calling (626) 445-7630 or by emailing