DR-4569-CA Final Public Notice

FINAL PUBLIC NOTICE: Alvarado-Niles Pipeline Seismic Improvement Project, Alameda County, California | HMGP 4569-282-13

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 Alameda County Water District, (sub-applicant) in Union City, Alameda County, California, to replace an existing 6-inch to 18-inch diameter steel and asbestos cement potable water main located beneath Alvarado-Niles Road with a new 14-inch, 16-inch, and 18-inch steel pipe along an approximately 1.7-mile similar alignment (proposed action). Pursuant to Executive Order 11988 (Floodplain Management), Executive Order 11990 (Protection of Wetlands), 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 overall purpose of the proposed action is to replace the asbestos cement pipeline segments that were identified as high priorities in the sub-applicant’s water infrastructure Seismic Vulnerability Assessment completed in 2008. The assessment determined that due to the soil composition, segments of the Alvarado-Niles Pipeline have a moderate to high risk of being damaged due to liquefaction during an earthquake. These pipeline segments are considered to have a "high" consequence of failure, as pipe failure could affect traffic on Alvarado-Niles Road, a major arterial thoroughfare, disrupt operations of key business, and potentially impact emergency access to and evacuation from residential and business areas. The new pipeline will improve water distribution reliability to an area susceptible to liquefaction and other earthquake hazards. In addition to the new main, appurtenances including fire hydrants and associated connections to fire hydrant laterals, air valves, and customer water service laterals will also be upgraded to flexible connections. Pipeline installation at the Dry Creek crossing, an open flood control channel near Western Avenue and Alvarado-Niles Road, would be accomplished via a seismically retrofitted aerial or raised crossing, such as supporting the pipeline on concrete piers drilled in the existing channel or installed on a pipe bridge that spans the drainage channel.

The project area is depicted on the FEMA Flood Insurance Rate Map (FIRM), Number 06001C0433G, effective 8/3/2009. The FIRM shows the proposed action lies within Zone AE, the base floodplain where base flood elevations are provided. The U.S. Fish and Wildlife Service National Wetlands Inventory Map shows the project is located within riverine wetlands.

Maps of the project area and its location within the floodplain and wetlands are available for public inspection. Parties interested in receiving a copy of either map should contact the FEMA Region IX Environmental Officer using contact information provided in this notice.

Three alternatives to the proposed action were considered: Alternative 1: No Action; Alternative 2: High-Density Polyethylene (HDPE) Pipe; and Alternative 3: Ductile Iron Pipe. Alternative 1 would result in no action being taken to mitigate seismic and flood hazards. This Alternative is not recommended because the risk of seismic and flood hazards, including damage to property and people, would remain. In addition, no action would increase the risk of failure due to potential vertical displacement since the existing pipeline material is asbestos cement with no flexible connections, and its design pre-dates current seismic standards, rendering the pipeline incapable of withstanding either a 475-year (Magnitude 6.67) or 975-year (Magnitude 7.1) seismic event.

The sub-applicant estimates that customers could lose water service for as long as 160 to 212 days, respectively, if no action is taken to harden the pipeline against these magnitude earthquakes. Fire flow services for firefighting would also be impacted, increasing the risk to property and public safety. Therefore, Alternative 1 is not feasible. Alternative 2 included the evaluation of high-density polyethylene (HDPE) as an alternate pipe material. This Alternative is not recommended because literature suggests that HDPE with bell and spigot gaskets, for example, allows permeation of lower-molecular weight organic solvents or petroleum products. In addition, the alignment of the pipeline resides within an area with historic groundwater contamination, and locations with underground storage tanks of petroleum products that could be potential future points of contamination. Therefore, Alternative 2 is not feasible. Alternative 3 included the evaluation of ductile iron pipe as an alternate pipe material. However, earthquake-resistant ductile iron pipe includes bell and spigot connections with joining gaskets. Similar to Alternative 2, research identified pipe materials, such as elastomers used in jointing gaskets and packing glands, may be subject to permeation by lower-molecular weight organic solvents or petroleum products. Therefore, Alternative 3 is not feasible. Other pipeline alignments were not considered since it would not be practicable to move a pipeline of this size to a different location to avoid the seismic and flood risks; therefore, it was necessary to determine the best pipeline material, valves, and connections able to mitigate against the loss of this essential pipeline. FEMA has determined that the proposed project is the only practicable alternative available; therefore, the proposed action must be taken at this location for the pipeline to serve its intended purpose.

The proposed action would have no significant adverse impact on the floodplain and would benefit the area by minimizing the impact of earthquakes and floods on human health, safety, or welfare, and results in an increase to the useful life of a structure or facility. The Alameda County Water District 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. All requests should be received no later than 15 days after publication of this notice. No action will be taken before this date.