1、Assessing Indirect Effects and Cumulative Impacts under NEPA 1 AASHTO PRACTITIONERS HANDBOOK The Practitioners Handbooks are produced by the Center for Environmental Excellence by AASHTO. The Handbooks provide practical advice on a range of environmental issues that arise during the planning, develo
2、pment, and operation of transportation projects. The Handbooks are primarily intended for use by project managers and others who are responsible for coordinating compliance with a wide range of regulatory requirements. With their needs in mind, each Handbook includes: key issues to consider; a backg
3、round briefing; practical tips for achieving compliance; and a list of reference materials. In addition, key regulations, guidance materials, and sample documents for each Handbook are posted on the Centers web site at http:/environment.transportation.org. American Association of State Highway and T
4、ransportation Officials Center for Environmental Excellence by AASHTO 12 August 2016 ASSESSING INDIRECT EFFECTS AND CUMULATIVE IMPACTS UNDER NEPA This Handbook is intended to assist practitioners in assessing indirect effects and cumulative impacts in the evaluation of transportation proj- ects unde
5、r the National Environmental Policy Act (NEPA). Issues covered in this Handbook include: Understanding the definitions of direct effects, indirect effects, and cumulative impacts Gathering the information needed for the analysis Deciding the appropriate scope and level of detail Carrying out the ana
6、lysis Identifying mitigation opportunities Documenting the analysis Using the transportation planning process to support NEPA- level studies of indirect effects and cumulative impactsCopyright 2016, Center for Environmental Excellence by AASHTO (American Association of State Highway and Transportati
7、on Officials). All Rights Reserved. This book, or parts thereof, may not be reproduced in any form without written permission of the publisher. Printed in the United States of America. This material is based upon work supported by the Federal Highway Administration under Cooperative Agreement No. DT
8、FH61-07-H-00019. Any opinions, findings, and conclusions or recommendations expressed in this publication are those of the Author(s) and do not necessarily reflect the view of the Federal Highway Administration. 2016 by the Center for Environmental Excellence by AASHTO. All rights reserved. Duplicat
9、ion is a violation of applicable law.Assessing Indirect Effects and Cumulative Impacts under NEPA 1 The requirement to assess indirect and cumulative impacts of proposed Federal actions was established in the Council on Environmental Quality (CEQ) regulations implementing the National Environmental
10、Policy Act (NEPA). Indirect effects are caused by the project or plan, but are separated from direct effects by time and/or distance. Indirect effects include induced growth and related environmental impacts. Cumulative impacts are the aggregate result of the incremental direct and indirect effects
11、of a project or plan, the effects of past and present actions, and effects of reasonably foreseeable future actions by others on resources of concern. This Handbook focuses primarily on the assessment of indirect effects and cumulative impacts for individual transportation projects. This Handbook al
12、so briefly describes a range of approaches for using the statewide or metropolitan transportation planning process to address indirect effects and cumulative impacts for a region or corridor, including the possibility of adopting a planning-level analysis for use in the NEPA process for an individua
13、l project. A consistent theme throughout this Handbook is the importance of maintaining a clear distinction between an indirect effects analysis and a cumulative impacts analysis. For that reason, those analyses are addressed separately in the Practical Tips section of the Handbook. Background Brief
14、ing This section introduces the key terms and concepts used in the assessment of indirect effects and cumulative impacts in the NEPA process. It also briefly describes key guidance documents. For a more extensive listing of guidance documents and research reports relating to indirect and cumulative
15、impacts analyses, refer to the Reference Materials section of this Handbook. Key Terms and Concepts Direct Effects. The CEQ regulations state that direct effects are “caused by the action and occur at the same time and place” 1Direct effects are typically well understood and predictable. Direct effe
16、cts are action-focused effects. Examples of common direct effects for transportation projects include residential and business displacements, the fill of wetlands to construct a roadway, or the removal of a historic structure. Indirect Effects. Indirect effects are those effects that “. . . are caus
17、ed by the action and are later in time and farther removed in distance, but are still reasonably foreseeable.” Indirect effects “may include growth-inducing effects and other effects related to induced changes in the pattern of land use, population density, or growth rate, and related effects on air
18、 and water and other natural systems, including ecosystems.” 2Indirect effects are action-focused effects. Two types of indirect effects are commonly recognized: induced-growth effects and encroachment-alteration effects. 3 Induced-Growth Effects. Induced-growth effects are changes in the location,
19、magnitude, or pace of future development that result from changes in accessibility caused by the project. An example of an induced-growth effect is commercial development occurring around a new interchange and the environmental impacts associated with this development. 1 40 CFR 1508.8. 2 40 CFR 1508
20、.8. 3 NCHRP Report 466, “Desk Reference for Estimating the Indirect Effects of Proposed Transportation Projects” (2002), p. 55. Overview 2016 by the Center for Environmental Excellence by AASHTO. All rights reserved. Duplication is a violation of applicable law.2 Assessing Indirect Effects and Cumul
21、ative Impacts under NEPA Encroachment-Alteration Effects. Encroachment-alteration effects are physical, chemical, or biological changes in the environment that occur as a result of the project but are removed in time or distance from the direct effects. An example of an encroachment effect is a long
22、-term decline in the viability of a population of a particular species as a result of habitat fragmentation caused by the project. These types of effects are sometimes categorized as direct effects rather than indirect effects. The categorization is not important as long as the NEPA document demonst
23、rates that the encroachment-alteration effects have been considered. Cumulative Impacts. A cumulative impact is “the impact on the environment which results from the incremental impact of the action when added to other past, present, and reasonably foreseeable future actions regardless of what agenc
24、y (Federal or non-Federal) or person undertakes such other actions. Cumulative impacts can result from individually minor but collectively significant actions taking place over a period of time.” 4 Distinctions between Direct, Indirect, and Cumulative Impacts TYPE OF EFFECT DIRECT INDIRECT CUMULATIV
25、E Nature of Effect Typical/Inevitable/Predictable Reasonably Foreseeable/Probable Reasonably Foreseeable/ Probable Cause of Effect Project Projects Direct and Indirect Effects Projects Direct and Indirect Effects and Effects of Other Activities Timing of Effect Project Construction and Implementatio
26、n At Some Future Time other than Direct Effect In the Past, at Time of Project Construction, or in the Future Location of Effect At the Project Location Within Boundaries of Systems Affected by the Project Within Boundaries of Systems Affected by the Project Source: NCHRP Report 403, Guidance for Es
27、timating the Indirect Effects of Proposed Transportation Projects (1998). “But-For” Relationship. As a general rule, a project may be considered to cause an impact if the project is necessary for the impact to occur. This relationship is sometimes described as a “but-for” relationship: that is, the
28、development would not have occurred but for the transportation project. A but-for condition can exist as a matter of lawe.g., if an action cannot take place without a permit. A but-for condition can also exist as a matter of facte.g., if a developer would choose not to build a shopping mall unless a
29、 nearby road is expanded. Necessary vs. Sufficient. Even when a project is a necessary condition for an impact to occur, there may beand often areother conditions that also need to be present in order for the impact to occur. Thus, while the transportation project may be a necessary condition, it ma
30、y not be a sufficient condition for the impact to occur. Other conditions that may be necessary for a development project typically include but are not limited to: suitable, available land for development or redevelopment. economic conditions that support development, e.g., markets, acceptable rate
31、of return on investment in land purchase, design, construction, and other costs. zoning and other land use controls and policies suitable for the type of development suggested by market conditions. other infrastructure that supports development, e.g., water and sewer service. amenities, e.g., school
32、s, access to recreational opportunities. “Reasonably Foreseeable.” Indirect and cumulative impacts must be considered if they are reasonably foreseeable. Impacts that are merely possible, or that are considered “speculative,” are not reasonably foreseeable. In one of the leading court decisions on t
33、his topic, the U.S. Court of Appeals for the First Circuit explained the legal standard as follows: Only those effects that are “likely” (or “foreseeable” or “reasonably foreseeable”) need be discussed, and, as in other legal contexts, the terms “likely” and “foreseeable,” as applied to a type of en
34、vironmental impact, are properly interpreted as meaning that the impact is sufficiently likely to occur that a person of ordinary prudence would take it into account in reaching a decision. 5 4 40 CFR 1508.7. 5 Sierra Club v. Marsh, 976 F.2d 763, 767 (1st Cir. 1992). 2016 by the Center for Environme
35、ntal Excellence by AASHTO. All rights reserved. Duplication is a violation of applicable law.Assessing Indirect Effects and Cumulative Impacts under NEPA 3 The CEQ provides a similar interpretation, requiring agencies to consider the “uncertain, but probable” indirect effects of their actions: The E
36、IS must identify all the indirect effects that are known, and make a good faith effort to explain the effects that are not known but are “reasonably foreseeable.” If there is total uncertainty about the identity of future land owners or the nature of future land uses, then of course, the agency is n
37、ot required to engage in speculation or contemplation about their future plans. But, in the ordinary course of business, people do make judgments based upon reasonably foreseeable occurrences. It will often be possible to consider the likely purchasers and the development trends in that area or simi
38、lar areas in recent years; or the likelihood that the land will be used for an energy project, shopping center, subdivision, farm, or factory. The agency has the responsibility to make an informed judgment, and to estimate future impacts on that basis, especially if trends are ascertainable or poten
39、tial purchasers have made themselves known. The agency cannot ignore these uncertain, but probable, effects of its decisions. 6 Other Terminology Issues. Just as it is important to understand when similar terms have different meanings, it also is important to understand when different terms have the
40、 same meaning. There is no substantive distinction in the CEQ regulations between “effect” and “impact,” nor is there a substantive distinction between “indirect” and “secondary.” To avoid confusion, it is good practice to use these terms consistently within a NEPA document. Effects vs. Impacts. The
41、 CEQ regulations use the terms “indirect effects” (40 CFR 1508.8) and “cumulative impacts” (1508.7). To be consistent with usage in the CEQ regulations, this Handbook also uses the terms “indirect effects” and “cumulative impacts.” This terminology is a matter of convention, and does not reflect a s
42、ubstantive distinction between the meaning of “effects” and “impacts,” which are described as synonymous in the CEQ regulations. 7The CEQ itself has not been consistent in its use of these terms: while the regulations refer to cumulative impacts, several CEQ guidance documents refer to “cumulative e
43、ffects,” including the CEQs handbook on this topic. In practice, it is acceptable to refer to effects or impacts, as long as the terms are used consistently. Indirect vs. Secondary. The term “secondary effects” is sometimes used as a substitute for “indirect effects.” While use of this term does not
44、 affect the legal adequacy of the analysis, the CEQ regulations refer only to “indirect effects” and do not use the term “secondary effects.” For consistency with the CEQ regulations, this Handbook exclusively uses the term “indirect effects.” Key Reference Documents There are many guidance document
45、s and reference materials that provide advice for practitioners on how to conduct indirect effects and cumulative impacts analyses. See the Reference Materials section of this Handbook for additional information on these guidance documents. CEQ. In 1997, the CEQ issued the Handbook, Considering Cumu
46、lative Effects under the National Environmental Policy Act. This Handbook is non-binding and is not considered a guidance document, but has been widely followed. There is no comparable CEQ handbook or guidance document for indirect effects. In 2005, the CEQ issued a memorandum on consideration of “p
47、ast actions” in cumulative impacts analyses. FHWA. In 2003, FHWA issued an interim guidance document, Questions and Answers Regarding the Consideration of Indirect and Cumulative Impacts in the NEPA Process. This interim guidance has never been finalized. It remains FHWAs most current and comprehens
48、ive guidance on indirect effects and cumulative impacts. State DOTs. Several state DOTs have developed their own guidance documents for conducting indirect effects and/ or cumulative impacts assessments, including California, Maryland, Montana, North Carolina, Ohio, Oregon, Pennsylvania, Texas, Wash
49、ington, and Wisconsin. See the Reference Materials section of this Handbook for references to state DOT guidance documents. NCHRP Reports. Several reports on indirect effects and cumulative impacts have been produced by the National Cooperative Highway Research Program (NCHRP), including NCHRP Report 403, Guidance for Estimating the Indirect Effects of Proposed Transportation Projects (1998). This report presents an eight-step process for 6 CEQ, “Forty Most Asked Questions Concerning CEQs National Environmental Policy Act Regu
