Utility Commission Hazard Mitigation Grant Public Notice

Hazard Mitigation Grants
Joint Federal, State, Local Public Notice

The Federal Emergency Management Agency (FEMA) and South Carolina Emergency Management Division (SCEMD) have received an application for Federal grant funding through the Hazard Mitigation Grant Program (HMGP). Funding for this grant was made available after the 4346 Presidential Declaration was made regarding Hurricane Irma of October 2017. Funding for the proposed project will be conditional upon compliance with all applicable federal, tribal, state, and local laws, regulations, floodplain standards, permit requirements, and conditions.

Under the National Environmental Policy Act (NEPA), federal actions must be reviewed and evaluated for feasible alternatives and for social, economic, historic, environmental, legal, and safety considerations. Under Executive Order (EO) 11988 and EO 11990 FEMA is required to consider alternatives to and to provide public notice of any proposed actions in or affecting floodplains and wetlands. EO 12898 also requires FEMA to provide the opportunity for public participation in the planning process and to consider potential impacts to minority or low-income populations.

Applicant

Town of Seabrook Island

Project Title

Seabrook Island Pump Station Emergency Generators

Project Description

The Charleston Regional Hazard Mitigation Plan (2016 Update and current 2016-2017 Draft) lists the retrofitting critical facilities or infrastructure to enhanced hazard resistance in accordance with the County of Charleston Facilities Master Plan Update “Building Utilization and Needs Survey” or other applicable plans as a top priority for Seabrook Island.

This project directly addresses this mitigation action by providing permanent auxiliary power to six (6) of the main Seabrook Island sewer pump stations (PS #3, PS #10, PS #11, PS #18, PS #20 and PS #22). Mobile emergency diesel generators were required in all of the most recent storm events to include Hurricanes Irma (2017) and Matthew (2016) where power has been lost due to wind and flooding.

Project Location

This project includes the addition of stand-by diesel emergency generators at the six (6) of the main pump stations for Seabrook Island. These stations serve the majority of the SIUC sewer service area and keeping these stations operational during major storm events is critical to public health and environmental protection. They are located across Seabrook Island and are shown on an attached overview map. The project to add generators to these six (6) pump stations will conform to all applicable federal, tribal, state and local laws, regulations and floodplain standards and permit requirements and conditions.

All of the stations are located within the AE flood zone and, therefore, a portion of the project must be located within the AE flood zone. Locating it to another site outside the AE flood zone would not meet the intended purpose of the project, which is to provide an emergency power source for six of the main SIUC pump stations. The design of the project will include an evaluation of the height of the generators, the generator pad and control panels to limit any possible flooding of the generators and panels themselves during future storm events. In addition, very limited land disturbance will be required and will be confined to a previously disturbed site; therefore, no impacts to the floodplain or any wetland areas are anticipated. Based on discussions with the Charleston County Floodplain Manager, the design of this project will conform to all applicable state and local floodplain protection standards. The Charleston County Floodplain Manager will review the final plans prior to construction and any required modifications will be made to ensure compliance with all applicable state and local floodplain protection standards. See attached location map.

Alternatives Considered

Alternatives to the stand-by diesel generators that were considered include: No action where no auxiliary power would be provided at these stations; and, the elimination of the pump stations and convey the wastewater using gravity sewer mains in lieu of force mains. SIUC would have to retrofit large portions of the wastewater collection system to install gravity sewer mains to convey the wastewater to one or two large regional pump stations or directly to the treatment plant. This alternative would include deep excavations and would likely require tunneling to cross wetlands and other water bodies. The one or two large regional pump stations would have to be upgraded to pump the larger volume of flow. Eliminating these pump stations would reduce, but not eliminate, the threat of power outages caused by hurricanes and other high wind weather events by decreasing the dependence on electric pumps in SIUC’s system. The No Action alternative was not considered to be feasible because it doesn’t meet the intent of the current Charleston Regional Hazard Mitigation Plan and would result in a high probability of sustained sewer system issues due to a power outage during storm events. The alternative to eliminate these six pump stations was not considered to be feasible due to cost (in excess of $3,000,000); environmental impacts; lack of suitable land; and, it would not eliminate the possibility of sewer system issues from power outages because some pumping would still be necessary.

Comment Period

Seabrook Island Utility Commission will be responsible for facilitating and monitoring the proposed project. Interested persons may direct any comments or questions to Tommy West, Manager at 843-768-0102 or twest@siuc.org. These are due within 15 days of this notice.