Transportation projects can affect a wide spectrum of environmental components. Early identification of impacts to the environment allows for avoidance, minimization, or timely mitigation of those impacts. Environmental impacts must be balanced with the public's need for safe and reliable transportation systems.
South Carolina air quality continues to comply with all National Ambient Air Quality Standards (NAAQS). The only exception to this is the portion of York County located closest to Charlotte, North Carolina, which has been designated "nonattainment." Within our State's nonattainment area, transportation projects should comply with plans for improving air quality.
Transportation projects can have major social and economic effects, and agencies are required to assess these kinds of effects as part of the NEPA process. The consistency of a transportation project with the goals and objectives of local comprehensive plans must be given consideration.
- Community Impact Assessment (CIA) is a process to evaluate the effects of a transportation project on a community and its quality of life. A CIA should include all items of importance to people. Public involvement is a key tool for CIAs.
- Public Information Meetings and Public Hearings are also one of the most effective means used by SCDOT to obtain feedback from affected communities.
Critical Areas and Coastal Zones
Cooperative efforts between the OCRM and SCDOT for project proposals, long-range planning, and policy development, are the best means to implement sound coastal management projects.
- Coastal waters are navigable waters of the U.S. that are subject to the ebb and flow of the tide.
- The State's Coastal Zone resources include coastal waters, tidelands, beach/dune systems, and beach. Coastal Zones are found in the State's eight coastal counties (Beaufort, Berkeley, Charleston, Colleton, Dorchester, Georgetown, Horry, and Jasper). Coastal Zone resources provide a dynamic yet fragile ecosystem designated as "Critical Area" under the law.
- The Critical Area plays a vital role in the marine food web, creates habitat and food sources for wildlife, and prevents erosion and storm damage from adjacent highland areas by absorbing wave energy and surge waters during storm events. All projects that will alter a Critical Area require a Critical Area permit from OCRM.
Essential Fish Habitat
Fish require a healthy environment to survive and reproduce. Essential Fish Habitat (EFH) includes all types of aquatic habitat that is tidally influenced (for example, wetlands, coral reefs, seagrasses, and streams) where fish spawn, breed, feed, or grow to maturity. Impacts from coastal and marine development threaten to alter, damage, or destroy these habitats. SCDOT works to avoid, minimize, or mitigate for these impacts through consultation with the NOAA NMFS.
- The Magnuson-Stevens Fishery and Conservation Act, Public Law 94-265, conserves and manages EFH through the preparation and implementation of Fishery Management Plans (FMPs).
- Projects having the potential to impact EFH must identify the habitat and potential effects.
Effective transportation decision making requires understanding the needs of different demographics.
- Executive Order 12898, Federal Actions to Address Environmental Justice in Minority Populations and Low-Income Populations, requires agencies to identify and address disproportionately high and adverse human health or environmental effects their projects may have on minority and low-income populations. For a project to impact an Environmental Justice (EJ) population, FHWA must determine that mitigation measures or alternatives that would reduce the disproportionately high and adverse effects are not practicable.
- Maps and reports of demographic, health, and environmental data are available from the USEPA's EJSCREEN online mapping tool.
A farmland assessment is conducted to ensure compliance with the Farmland Protection Policy Act (FPPA, 7 USC §4201 et seq.) and FHWA's Guidelines for Implementing the Final Rule of the Farmland Protection Policy Act for Highway Projects. The FPPA is intended to reduce and minimize impacts that federal projects may have on farmland and protect farmland from irreversible conversion to nonagricultural uses.
- A Farmland Impact Conversion Rating for Corridor Type Projects, Form NRCS-CPA-106, should be completed for alternatives to evaluate adverse effects to prime farmland.
- Maps and listings of farmland classification are available from the NRCS Web Soil Survey. After creating your Area of Interest (AOI), Farmland Classification is available on the Soil Data Explorer tab under the Land Classifications drop-down.
The majority of hazardous materials sites encountered for transportation projects are gas stations. Given their proximity to our state's roads, it is not uncommon to encounter storage tanks, monitoring wells, or contaminated soil. It is the policy of the SCDOT to avoid the acquisition of underground storage tanks (USTs) and other hazardous materials, if possible. If avoidance is not a viable alternative, tanks and other hazardous materials will be tested and removed and/or treated in accordance with the requirements of the USEPA and SCDHEC.
Evaluating existing and future land use for transportation projects helps preserve or enhance valued resources and facilitates sustainable communities. Land use plans and policies are normally reflected in an area's comprehensive development plan.
- Alternatives are evaluated for consistency with a comprehensive development plan adopted for the project area and any other plans used in the development of the transportation plan.
- Secondary social, economic, and environmental impacts of any substantial, foreseeable, induced development are considered for each alternative, as well as planned and unplanned growth.
The Migratory Bird Treaty Act, 16 USC §703 et seq.,forbids the wasteful take of birds and their use in commercial trade. It prohibits pursuing, hunting, taking, capturing, or killing any migratory bird, or any part, feather, nest, or egg thereof, without a permit from the USFWS (50 CFR §10 et seq.) The Act protects 836 bird species and has no provision for incidental take, including unknowing or unintentional take. The greatest potential for incidental take to occur is during bridge replacements.
- Existing bridges should be examined for the presence of nests prior to replacement.
- If nests are found during breeding season, a moratorium will be put in place to delay demolition of the existing bridge until the young have left the nest.
- In cases where construction begins before nesting season, netting can be used around the bridge to prevent birds from nesting on the bridge when breeding season starts.
Noise impacts are assessed for all federal projects. The SCDOT Traffic Noise Abatement Policy addresses the impact of highway traffic noise on residential neighborhoods and in other noise-sensitive areas, such as churches, schools, hospitals, and certain public recreational areas. This policy is based on FHWA regulations, 23 CFR §772. Abatement measures for noise level reduction are considered for:
- Highways built at a new location
- Existing highway redesign involving a significant change to its horizontal or vertical alignment
- Increased number of through traffic lanes on an existing highway
Federally funded projects that involve the use of land from a publicly owned recreation facility require evaluation under Section 4(f) of the U.S. Department of Transportation Act (49 §USC 303) to determine if the land meets defining criteria. The Section 4(f) process was revised by Section 6009 of the Safe, Accountable, Flexible, Efficient Transportation Equity Act: A Legacy for Users (SAFETEA-LU; Public Law 109-59) and a Final Rule issued by FHWA (23 CFR §774). FHWA is responsible for making the Section 4(f) decision for highway projects.
- Section 4(f) properties include publicly owned parks, recreation lands, wildlife or waterfowl refuges, and historic properties.
- For a use of a Section 4(f) property to occur, FHWA must determine that there is no feasible and prudent alternative that avoids the Section 4(f) property and that the project includes all possible planning to minimize harm to the property. A use substantially impairs the activities, features, or attributes of a 4(f) property.
- A de minimis impact determination does not require analysis of feasible and prudent avoidance alternatives. For publicly owned public parks, recreation areas, and wildlife and waterfowl refuges, a de minimis impact is one that will not adversely affect the activities, features, or attributes of the 4(f) property. For historic properties, a de minimis impact means FHWA determined that either no historic property is affected by the project or that the project will have "no adverse effect" on the historic property.
Streams and Wetlands
Streams are natural or channelized drainage features resulting from stormflow, baseflow, or a combination of the two. Wetlands are areas that are saturated or inundated at least 5 percent of the growing season by surface or ground water at a frequency and duration sufficient to support, and under normal circumstances do support, a prevalence of vegetation typically adapted for life in saturated soil conditions.
- Streams and wetlands present within a proposed project area should be delineated based on criteria from the USACE Wetland Delineation Manual (1987) and corresponding Regional Supplement.
- A Jurisdictional Determination (JD) must be made by the USACE to define the limits of Federal jurisdiction. Jurisdictional features are protected under Section 404 of the Clean Water Act (CWA) and are regulated by both the USACE and USEPA.
- Executive Order 11990, Protection of Wetlands, requires agencies to avoid to the extent possible adverse impacts to and modification of wetlands when there is a practicable alternative.
Threatened and Endangered Species
Protection of threatened and endangered species conserves the genetic diversity of our ecosystems.
- Endangered species are protected by the Endangered Species Act, 16 USC §1531 et seq., and regulated jointly by the USFWS and NOAA NMFS, 50 CFR §402.
- Habitat necessary for a species' survival, called "critical habitat," is also protected under the law.
- Mitigation measures for threatened or endangered species can include (but are not limited to) altering the project to avoid impacts, translocating the species, altering the timing of construction to a certain season, or other measures developed in consultation with the USFWS.