Lytle Creek Bank Protection and Habitat Preservation

San Bernardino County, CA

PACE studied the watershed and performed planning and design of stream bank protection facilities along Lytle Creek for a 3,500-home residential development located adjacent to the City of Rialto and the Lytle Creek alluvial fan floodplain. The revetment design covers 7.1 miles of stream bank to satisfy the need for flood protection. A sophisticated hydraulic and fluvial analysis was performed to accommodate the challenges of alluvial fan geometry, sensitive habitat, habitat restoration in the Sycamore Creek, in-stream existing gravel mines, large sediment delivery of cobbles and boulders, and sensitive endangered species.

The stream bank protection utilized a grouted rock revetment to address the dynamic nature of the floodplain and extreme hydraulic conditions. A detailed impacts assessment was performed on the floodplain to satisfy environmental resource agencies, which required complex two-dimensional hydraulic models and evaluation of the influence on native vegetation within the floodplain. In addition to the stream bank revetment, a gabion groin system protects an endangered species habitat preservation area.

Key Features:

• Complex fluvial model / scour analysis
• Alternative facility sizing
• Revetment feasibility study
• Environmental hydraulic impact assessment
• Sensitive species habitat protection
• Gabion groin stream bank stabilization
• Revetment PS&E
• Complex two-dimensional hydraulic modeling
• Geomorphic investigation
• Operation and maintenance manual
• CLOMR processing
• USACE 408 permit processing