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Last Updated: Friday, February 3, 2012 10:57 AM

CEQA Guidelines for Cumulative and Indirect Impacts

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CEQA GUIDELINES FOR CUMULATIVE AND INDIRECT IMPACTS

This paper is a brief primer for Caltrans planners who must analyze cumulative impacts and indirect impacts to fulfill CEQA requirements. In general, your analysis and documentation will comply with both the National Environmental Policy Act (NEPA) and the California Environmental Quality Act (CEQA) when you follow the Guidance for Preparers of Cumulative and Indirect Impact Assessments, but some subtle differences exist between the analyses performed under the two statutes. This issue paper presents a few things that you should keep in mind to ensure that CEQA requirements are met. This paper will:

  • Define the applicable terms used in CEQA, and
  • Summarize the CEQA Guidelines for impact analysis and disclosure.

For additional information about CEQA, follow the links provided at the end of this paper.

Contrary to NEPA, CEQA and the CEQA Guidelines use the terms "effects" and "impacts" interchangeably.

HOW CEQA DEFINES EFFECTS

Effects

Contrary to NEPA, CEQA and the CEQA Guidelines use the terms “effects” and “impacts” interchangeably. The CEQA Guidelines define three types of effects (or impacts):

  1. Direct or primary effects that are caused by a project and occur at the same time and place.
  2. Indirect or secondary effects that are reasonably foreseeable and caused by a project, but occur at a different time or place. The CEQA Guidelines state the following:

    An indirect physical change in the environment is a physical change…which is not immediately related to the project, but which is caused indirectly by the project. If a direct physical change in the environment in turn causes another change in the environment, then the other change is an indirect change in the environment (Section 15064 (d)(2)).

    …Indirect or secondary 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 and water and other natural systems, including ecosystems (Section 15358)(a)(2)).

    As stated in Section 15126.2(d) of the Guidelines, a growth-inducing impact could occur if:

    …the proposed project could foster economic or population growth, or the construction of additional housing, either directly or indirectly, in the surrounding environment. Included in this are projects that would remove obstacles to population growth (a major expansion of a waste water treatment plant might, for example, allow for more construction in the service areas). Increases in the population may tax existing community service facilities, requiring construction of new facilities that could cause significant environmental effects.

    A project may have some characteristic that may encourage and facilitate other activities that could significantly affect the environment, either individually or cumulatively. For example, the construction of a new sewage treatment plant may facilitate population growth in the service area due to the increase in sewage treatment capacity, which may lead to an increase in air pollution from man-made mobile and stationary sources. Section 15126.2(d) of the Guidelines concludes by cautioning the planner that “It must not be assumed that growth in any area is necessarily beneficial, detrimental, or of little significance to the environment.”

  3. Cumulative effects. Section 15355 of the CEQA Guidelines states: "Cumulative impacts" refers to two or more individual effects which, when considered together, are considerable or which compound or increase other environmental impacts.

    (a) The individual effects may be changes resulting from a single project or a number of separate projects.

    (b) The cumulative impact from several projects is the change in the environment which results from the incremental impact of the project when added to other closely related past, present, and reasonably foreseeable probable future projects. Cumulative impacts can result from individually minor but collectively significant projects taking place over a period of time.

    Important direction to the practical use of this definition is found in Section 15130 of the CEQA Guidelines:

    (a)(1) As defined in Section 15355, a cumulative impact consists of an impact which is created as a result of the combination of the project evaluated in the EIR together with other projects causing related impacts [emphasis added].

    (b)…The discussion of cumulative impacts shall…focus on the cumulative impact to which the identified other projects contribute rather than the attributes of other projects which do not contribute to the cumulative impact [emphasis added].

    For example, if another project contributes only to a cumulative impact upon natural resources, its impacts on public services need not be discussed as part of cumulative impact analysis.

    Taken together, these elements define what counts for the practitioner and help to focus the evaluation upon other actions that are closely related in terms of impact on the resource— not closely related project types.

Significant Effects

Projects can cause significant impacts by direct physical changes to the environment or by triggering reasonably foreseeable indirect physical changes. Physical changes caused by a project can contribute incrementally to cumulative effects that are significant, even if individual changes resulting from a project are limited. You must determine whether the cumulative impact is significant, as well as whether an individual effect is “cumulatively considerable.” This means “the incremental effects of an individual project are significant when viewed in connection with the effects of past projects, the effects of other current projects, and the effects of probable future projects” (Guidelines Section 15064(h)(1)).

When considering the relationship between the cumulative condition and the incremental effect of an individual project, keep in mind that “The mere existence of significant cumulative impacts caused by other projects alone shall not constitute substantial evidence that the proposed project’s incremental effects are cumulatively considerable” (Guidelines Section 15064(h)(4)).

See footnote: "The CEQA Guidelines define three types of effects (or impacts)."

IMPACT ANALYSIS AND DISCLOSURE

Analysis

In general, if you follow the approach provided by the Guidance for Preparers of Cumulative and Indirect Impact Assessments, your analysis will satisfy CEQA requirements. If you are conducting an analysis for a CEQA document, then you may choose to follow the methodology described in this section.

If you determine that the project will result in a significant indirect or cumulative impact, the CEQA analysis must also identify feasible mitigation measures for each significant environmental effect identified in the EIR. The CEQA Guidelines state that, “With some projects, the only feasible mitigation for cumulative impacts may involve the adoption of ordinances or regulations rather than the imposition of conditions on a project-by-project basis” (Guidelines Section 15130(c)). However, CEQA also specifies that, “If the lead agency determines that a mitigation measure cannot be legally imposed, the measure need not be proposed or analyzed. Instead, the EIR may simply reference that fact and briefly explain the reasons underlying the lead agency’s determination” (Guidelines Section 15126.4(a)(5)).

The CEQA Guidelines provide two methods for an adequate analysis of cumulative impacts:

  1. The list approach, or
  2. The projection approach.

In practice, you may decide on a hybrid approach that uses the list or projection method for different impacts or concerns, depending upon the type of effects, available data, or other conditions of your analysis.

See footnote: "The CEQA Guidelines provide two methods for an adequate analysis of cumulative impacts."

List Approach (Guidelines Section 15130(b)(1)(A))

The list approach identifies all of the past, present, and probable future projects contributing to the cumulative impact, including projects that are outside of the control of Caltrans. As described in the Defining Resource Study Areas issue paper, you should be prepared to have project lists that differ from subject to subject. (For example, water-type projects for effects related to fish may differ from traffic-type projects for effects related to traffic, air, and noise.)

Projection Approach (Guidelines Section 15130(b)(1)(B))

Instead of using the list approach, you may base the cumulative impact analysis on a summary of projections of future development and impacts contained in an adopted general planning or related planning document, or in a prior environmental document that has been certified. These documents must be available to the public and actually describe or evaluate the regional or areawide conditions contributing to the cumulative impact.

When using either the list or projection approach, Section 15130(b) of the CEQA Guidelines presents several rules for discussing cumulative impacts. According to the Guidelines, your analysis should provide the following:

  • “…define the geographic scope of the area affected by the cumulative effect and provide a reasonable explanation for the geographic limitation used” (Guidelines Section 15130(b)(3)).
  • “A summary of expected environmental effects to be produced by [related] projects with specific reference to additional information and where that information is available; and” (Guidelines Section 15130(b)(4)).
  • “A reasonable analysis of cumulative impacts of the relevant projects. An EIR shall examine reasonable and feasible options for mitigating or avoiding the project’s contribution to any significant cumulative effects (Guidelines Section 15130(b)(5)).

Disclosure

CEQA requires that significant impacts be specifically identified and disclosed. As stated in the Guidelines, “Direct and indirect significant effects of the project on the environment shall be clearly identified and described, giving due consideration to both the short-term and long-term effects” (Guidelines Section 15126.2(a)).

The CEQA Guidelines require a discussion of cumulative impacts of a project when a project’s incremental effect is cumulatively considerable. “Cumulatively considerable” means that the incremental effects of an individual project are considerable when viewed in connection with the effects of past, current and probable future projects. As stated in Section 15130(b):

The discussion of cumulative impacts shall reflect the severity of the impact and their likelihood of occurrence, but the discussion need not provide as great detail as is provided for the effects attributable to the project alone. The discussion should be guided by standards of practicality and reasonableness, and should focus on the cumulative impact to which the identified other projects contribute rather than the attributes of other projects which do not contribute to the cumulative impact.

“Cumulatively considerable” means that the incremental effects of an individual project are considerable when viewed in connection with the effects of past, current, and probable future projects.

MORE INFORMATION

For more extensive information about CEQA (Public Resources Code Sections 21000 through 21178) and the CEQA Guidelines (California Code of Regulations, Title 14, Chapter 3, Sections 15000 through 15387), refer to the following online documents:

FOOTNOTES

The CEQA Guidelines define three types of effects (or impacts):

  1. Direct or primary effects that are caused by a project and occur at the same time and place.
  2. Indirect or secondary effects that are reasonably foreseeable and caused by a project, but occur at a different time or place.
  3. Cumulative effects, which refer to two or more individual effects which, when considered together, are considerable or which compound or increase other environmental impacts.

The CEQA Guidelines provide two methods for an adequate analysis of cumulative impacts:

  1. The List Approach, which identifies all of the past, present and probable future projects contributing to the cumulative impact, including projects that are outside of the control of Caltrans.
  2. The Projection Approach, which relies upon the cumulative impact analysis on a summary of projections of future development and impacts contained in an adopted general planning or related planning document, or in a prior environmental document that has been certified. These documents must be available to the public and actually describe or evaluate the regional or areawide conditions contributing to the cumulative impact.

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