Abstract
As the United States begins large-scale deployment of offshore wind energy facilities, an important challenge for developers and regulators is the assessment of potential seascape, landscape, and visual impacts on important coastal scenic, historic, and recreational resources; Native American tribal properties and treasured seascapes; commercial interests dependent on tourism; and the private property of coastal residents. This document describes the methodology for seascape, landscape, and visual impact assessment (SLVIA) that the U.S. Department of the Interior (DOI) Bureau of Ocean Energy Management (BOEM) uses to identify the potential impacts of offshore wind energy developments in Federal waters on the Outer Continental Shelf (OCS) of the United States. This methodology document describes what is considered in the SLVIAs submitted by offshore wind project developers to BOEM and how decisions about expected impacts of offshore wind developments are made. This SLVIA methodology applies to any offshore wind energy development proposed for the OCS and considered by BOEM, as directed by the Energy Policy Act of 2005 and in compliance with the Outer Continental Shelf Lands Act and the National Environmental Policy Act of 1969 (NEPA). The SLVIA has two parts: seascape and landscape impact assessment (SLIA) and visual impact assessment (VIA). SLIA analyzes and evaluates impacts on both the physical elements and features that make up a landscape or seascape and the aesthetic, perceptual, and experiential aspects of the landscape or seascape that make it distinctive. These impacts affect the “feel,” “character,” or “sense of place” of an area of landscape or seascape, rather than the composition of a view from a particular place. In SLIA, the impact receptors (the entities that are potentially affected by the proposed project) are the seascape/landscape itself and its components, both its physical features and its distinctive character. Visual impact assessment (VIA) analyzes and evaluates the impacts on people of adding the proposed development to views from selected viewpoints. VIA evaluates the change to the composition of the view itself and assesses how the people who are likely to be at that viewpoint may be affected by the change to the view. Enjoyment of a particular view is dependent on the viewer, and in VIA, the impact receptors are people. The inclusion of both SLIA and VIA in the BOEM SLVIA methodology is consistent with NEPA’s objective of providing Americans with aesthetically and culturally pleasing surroundings and its requirement to consider all potentially significant impacts of development. The BOEM SLVIA methodology is modeled on the methodology in use in the United Kingdom. It considers SLIA and VIA as two closely related but separate impact assessments: Both use similar impact assessment processes, and the majority of potential impacts for both the SLIA and the VIA are associated with the visibility of the offshore and onshore wind project components. However, the SLIA impact receptors and types of potential impacts differ from those in the VIA, leading to different conclusions about the ultimate effects of the project on seascape/landscape (assessed in SLIA) and on people (assessed in VIA). The SLVIA process includes six major phases: 1. The proponent provides the construction and operation plan (COP) that describes the project in detail, any alternatives under consideration, and the project design envelope (PDE), if the PDE approach is being used. Best management practices (BMPs) for mitigating the seascape, landscape, and visual impacts of the project that are incorporated into the project design and included in the COP are assumed to be implemented for purposes of the SLVIA. 2. The geographic scopes of the SLIA and the VIA—that is, the areas within which impacts will be assessed—are identified. vii 3. Descriptions of impact receptors and existing conditions for use in the SLIA and the VIA are prepared: a. For the SLIA, this step includes describing the seascape/landscape character and the contributing elements of the potentially affected seascape/landscape character areas (SCAs/LCAs). b. For the VIA, this step includes describing the important views, the potentially affected viewers, the viewpoints where the viewers are located, and the existing conditions at and around the viewpoints. c. Applicable laws, ordinances, and regulations (LORs) are also reviewed for applicability to the SLIA and VIA. 4. The potential impacts of all phases of the proposed project and alternatives, including the PDE (if applicable), are identified and described, and the impact levels determined. Potential seascape and landscape impacts are identified separately from visual impacts. The assessment of visual impacts is based, in part, on the use of visual simulations of the proposed project and alternatives, and simulations may also be used for assessment of seascape and landscape impacts. After the nature and extent of the impacts have been identified, the levels of the potential impacts are determined. This requires combining judgments about the sensitivity of the seascape/landscape and visual impact receptors and the magnitude of the impacts, and then combining the sensitivity and magnitude judgments to determine the overall level of the impacts. Although the evaluation of impact level is ultimately a professional judgment, as are the evaluations of the individual criteria, the method by which the evaluation is made is systematic, based on accepted criteria, and clearly documented. 5. Assessment of impacts from reasonably foreseeable planned actions for both seascape/landscape and visual resources are conducted. After the nature and extent of these impacts have been identified, the impact levels are evaluated. 6. Additional recommended mitigation measures beyond those included in the COP may be identified. These could include mitigation required by BOEM as a condition for approval of the project or other mitigation actions agreed to by the developer.