Proposed Antelope Creek Flood Control Project
This is a multi-objective water efficiency and regional flood control improvement project proposed within the Dry Creek Watershed area of the American River Basin. The project will meet multiple planning objectives by improving water supply, water quality, flood protection, ecosystem restoration and an existing public recreation corridor. The project is being proposed through a collaboration of two local agencies, the Placer County Water Agency (PCWA) and the Placer County Flood Control and Water Conservation District (District).
This multi-objective effort includes a regional flood control project on Antelope Creek just downstream of the Highway 65 crossing located within the Dry Creek Watershed. Through the design and construction of several on-channel weirs along an existing open space protected reach of the creek, the project will provide flood control and flood damage reduction benefits to repeatedly damaged areas of downtown Roseville. The project would reduce peak flood flows over a wide range of flood events, enhance existing riparian corridor ecosystems, and improve water quality through groundwater recharge and natural treatment of temporarily stored flood waters within the floodplain. Both ecosystem restoration and public recreational opportunities will be enhanced wherever possible within the floodplain of Antelope Creek, which currently includes a multi-purpose public trail system. In-stream improvements will include bank re-contouring to ensure overbank flows, specific habitat enhancements for fisheries, removal of invasive plant species and replanting with natives. An interpretive trail sign system is also proposed to help educate the public on the project as they utilize the existing multi-purpose trail system.
The goal of PCWA’s water efficiency component of this project is to eliminate or reduce the amount of sediment that may enter a natural water way from the Antelope and Caperton canals, or, from the area between the canal and natural waterway, by installing energy dissipaters and/or other feature to capture sediment at the canal release points and increasing the height of the canal walls in those locations where there is a potential of overtopping the canal walls. Gunite, a cement and sand mixture that is “shot in place” with compressed air, will be used to create the desired feature at the canal outlets and to increase the height of the canal walls. To achieve the greatest amount of effectiveness and reduce potential sediment transport in the canal, both sides and the floor of the canal will be gunited in the identified reaches of the Antelope and Caperton Canals. Both the Antelope and Caperton Canal lining components were identified within PCWA’s 2004 PCWA Canal and Reservoir Feasibility Study Report and PCWA’s grant funded East Loomis Basin Canal Efficiency Study.
The current status for both project components (flood control and water efficiency) is that engineering feasibility study documents have been completed and both are ready to move directly into the permitting and design phases. Two grant applications have been submitted for consideration to the State Department of Water Resources under their Integrated Regional Water Management (IRWM) Proposition 84 and 1E grant programs.
- Slight increase to the footprint of the existing, FEMA recognized 100-year floodplain limits
- Detention of flood flows from the 2-year event on up to a 100-year event
- Re-vegetation plan with native species
- Removal of invasive and non-native plant species
- Stream channel restoration components
- Recreational trail, trailhead parking and interpretive signing components
- Minimized long term operations and maintenance activities
- More efficient water delivery canals
- Reduced sediment loads into the creek system