Powerline Plan and Environ. Assessment Jan. 2013 - Flood Control ...

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Powerline Flood Retarding Structure Pinal County, AZ Draft Supplemental Watershed Plan and Environmental Assessment Fish and Wildlife: No fish present in the project area. Mesquite bosque located upstream of structure. Flooding: Homes, businesses, and infrastructure are at high risk of flood damages if no action is taken. Geology: An earth fissure has been discovered adjacent to the Powerline FRS; Land subsidence at Powerline FRS and the northern 1/3 of Vineyard Road FRS is expected to continue in the near future. Migratory Birds: The project area contains suitable habitat for the western burrowing owl (Athene cunicularia hypugaea) which is protected under the Migratory Bird Treaty Act.. Prime Farmland: Prime farmland downstream of structure is at high risk of flood damages if no action taken. Public Health and Safety: Public health and safety is at high risk in the event of a catastrophic failure of the dam if no action taken. Transportation: Major local roads are located downstream and area at high risk of flood damage if no action is taken. Threatened and Endangered Species: The U.S. Fish and Wildlife Service (USFWS) threatened, endangered, proposed, and candidate species list for Pinal and Maricopa Counties, as well as the Arizona Game and Fish Department (AGFD) Heritage Data Management System (HDMS), were reviewed. There are no known occurrences of any threatened or endangered species or critical habitat within the project area. Suitable habitat is present for the Tucson shovel-nosed snake (Chionactis occipitalis klauberi) and dispersal habitat is present for the Sonoran desert tortoise (Gopherus agassizii). These are candidate species for the USFWS and may become listed in the future and warrant additional assessment. Desert tortoise has the potential to occur within the project area. The project contains suitable habitat for the western burrowing owl (Athene cunicularia hypugaea) which is protected under the Migratory Bird Treaty Act. Vegetative Community: Mesquite Bosque located upstream of structure. Water Resources: The Central Arizona Project canal is located downstream of the structure and is at high risk of flood damages if no action is taken. Alternative Plans Considered: The project alternatives that were considered as part of this study include the following: • No Federal Action/Future Without Project: Powerline FRS remains in unsafe condition until Sponsor’s eventual Rehabilitation or Replacement of the dam; • Decommissioning by Replacing the Powerline FRS with a Channel to Vineyard Road FRS; • Decommissioning by Replacing the Powerline FRS with Basins and Channels; • Raise and Rehabilitate the Powerline FRS. USDA- NRCS Page 1-3 January 2013 Kimley-Horn and Associates, Inc.
Powerline Flood Retarding Structure Pinal County, AZ Draft Supplemental Watershed Plan and Environmental Assessment Estimated Project Costs: Item PL 83-566 Funds ($) Other Funds ($) 1/ Total ($) Construction Cost $14,826,200 $7,321,800 $22,148,000 Technical Assistance $600,000 $651,500 $1,251,500 Project Administration $50,000 $10,000 $60,000 Land Rights (Sponsors) $0 $0 $0 Required Permits (Sponsors) $0 $434,300 $434,300 Total $15,476,200 $8,630,300 $23,893,800 1/ The Sponsor’s annual operation and maintenance cost for the project is $212,700. Estimated Project Benefits: An estimated 27,100 current residents, associated homes, businesses, and infrastructure are protected from catastrophic dam failure and flooding. Additional residents and infrastructure will be protected in the future as development continues to occur in the downstream benefitted area. Category Average Annual Equivalent Benefits Beneficial Annual 1/ $0 Adverse Annual $1,006,700 Net Beneficial ($1,006,700) Benefit-Cost Ratio 0.0 to 1.0 1/ The proposed project will provide an estimated $14,779,300 in average annual equivalent damage reduction benefits. However, as the "no action" or future without project alternative also provides this same benefit stream, the project does not have a positive incremental benefit. The benefits of the project are tied to reducing the risk of catastrophic failure of the existing structures and thus reducing the risk to life and property, as described in the plan. Funding Schedule: Powerline FRS FY 2022 (Vineyard Road FRS FY 2018; Rittenhouse FRS FY 2024) Period of Analysis: 103 Years Project Life: 100 Years Environmental Effects and Impacts: 1. Cultural Resources – Sites in the area of potential effects that will not be subject to projectrelated impacts will be avoided by project implementation activities. Data recovery studies will be performed to mitigate impacts to all sites likely to suffer project-related impacts. Based on known sites in the vicinity, the majority of the cultural resources present would be either prehistoric sites without evidence of habitation (which might USDA- NRCS Page 1-4 January 2013 Kimley-Horn and Associates, Inc.
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Powerline Flood Retarding Structure
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Signal Butte Rd Meridian Rd Ironwoo
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POWERLINE FRS TYPICAL SECTION
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Ironwood Rd Gantzel Rd Mountain Vie
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Figure 22 Figure 21 - Conceptual Mu
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Exhibit A-2 - Emergency Spillway Di
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Price Price Price Dobson Alma Schoo
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