DR-4434-CA Public Notice 003
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FINAL PUBLIC NOTICE: Mel Canyon Debris and Sediment Catchment Basin, Los Angeles County, California | HMGP 4344-397-122
The U.S. Department of Homeland Security’s Federal Emergency Management Agency (FEMA) proposes to provide federal financial assistance under the Hazard Mitigation Grant Program to the City of Duarte in Los Angeles County, California, to mitigate impacts from sediment and debris that wash out from two canyons north of Mel Canyon Road by installing a catchment basin (proposed action). Pursuant to Executive Order 11988 (Floodplain Management) and FEMA’s implementing regulations at Title 44 of the Code of Federal Regulations Part 9, FEMA hereby provides interested parties with a notice of its final decision and an explanation of the alternatives that were considered.
The purpose of the proposed action is to reduce mudflow hazards along Mel Canyon Road, surrounding residential streets, and adjacent properties. The proposed action consists of 1) vegetation clearing and 2.46 acres of grading to form the catchment basin; 2) constructing a gabion vertical drop structure or basin at the southern end of the project area; 3) installing reinforced concrete pipes with catch basins, flexible ring nets, and gabion walls upslope of the drop structure; and (4) constructing gates and fencing to contain the area and prohibit public access, asphalt roadways to facilitate maintenance access, driveway aprons, and drainage features.
The project area is depicted on the FEMA Flood Insurance Rate Map (FIRM), Map Number 06037C1415F, effective September 26, 2008. The proposed action lies within Zone D, an area that has possible but undetermined flood hazards. The U.S. Fish and Wildlife Service National Wetlands Inventory map shows potential freshwater forested/shrub wetlands within the eastern portion of the project area. Based on a review of high-resolution aerial imagery and ground-level photos from the field review and site assessment in June 2021, the area does not support prolonged periods of inundation. The project area does not have defined riparian areas, wetland habitat, or persistent surface water features.
A map of the project area and its location within the floodplain is available for public inspection. Parties interested in receiving a copy of the map should contact the FEMA Region IX Environmental Officer using contact information provided in this notice.
Two alternatives to the proposed action were considered: Alternative 1, No Action; and Alternative 2: Concrete Structure. Under Alternative 1, no action would be undertaken. Therefore, Alternative 1 is not recommended because mudflows and associated damage would continue to occur. During an event, sediment and debris would spill out onto the adjacent residential streets and the roadways would become impassable. Alternative 2 included construction of a large concrete catchment basin. This Alternative is not recommended due to the high cost. FEMA has determined that the proposed project is the only practicable alternative available; therefore, the proposed action must be located in the floodplain. The proposed action would have no significant adverse impact on the floodplain and would benefit the area by reducing the risk of flooding and flood damage. Therefore, measures to minimize impacts on the floodplain are not necessary. The City of Duarte has declared that the proposed action conforms to local floodplain standards, and would be responsible for the management, construction, and maintenance of the proposed action.
Additional information about FEMA’s proposed action may be requested by writing the FEMA Region IX Environmental Officer at FEMA, 1111 Broadway, Suite 1200, Oakland, California 94607, or fema-rix-ehp-documents@fema.dhs.gov, or calling (510) 627-7027. All requests should be received no later than 15 days after publication of this notice. No action will be taken before this date.