Arroyo Seco Watershed Assessment
2. Hahamongna Watershed Park
Arroyo Seco Channel Improvements
| Purpose: | To restore a stable channel planform, open water features, sediment and debris capture zones and aquifer recharge facilities within the riparian corridor of the Hahamongna Watershed Park (HWP). |
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| Location: | The Arroyo Seco channel flowing through the Hahamongna Watershed park between the Jet Propulsion Laboratory bridge and Devil’s Gate Dam. |
The Arroyo Seco channel flows through the Hahamongna Watershed Park (HWP) between the Jet Propulsion Laboratory (JPL) bridge and Devil's Gate Dam The HW) provides multiple benefits that include water supply augmentation; flood water, sediment and debris capture and storage; passive and active recreation and native ecosystem habitats. Unfortunately, the park has experienced degradation of habitats and infrastructure due to repeated impacts from sediment- and debris-laden floodwaters. The intent of this project is to reestablish a stable channel planform, open water feature, sediment and debris capture zones and aquifer recharge facilities within the riparian corridor of the HWP, in accordance with the HWP master plan.
Key Project Objectives:
- Reduce degradation of the channel due to sediment- and debris-laden floodwaters.
- Improve water quality due to groundwater/surface water interactions
- Restore endangered riverine and upland ecosystem communities.
- Reestablish wildlife migration corridors
- HWP Master Plan (2003)
- – Water and natural resource education and utilization
- – Preservation of native plants and habitat
- – Native American culture
- – Passive and active recreation
Key Project Components
- Develop seasonal pool behind Devil’s Gate Dam to support native habitat, increase storage, and allow for sediment accumulation
- Create braided stream channel upstream of flood management/water conservation pool
- Create sediment and debris capture zones which mimic alluvial fan processes
- Enhance passive (e.g., wildlife viewing) and active (e.g., disc golf) recreation alternativesRestore native vegetation (e.g., alluvial sage scrub) in various locations