#2 OPSD Cumulative Impact Guidance

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5) Cumulative effects analysis on natural systems must use natural ecological boundaries and analysis of human communities must use the actual sociocultural boundaries to ensure including all effects. 6) Cumulative effects may result from the accumulation of similar effects or the synergistic interaction of different effects. 7) Cumulative effects may last for many years beyond the life of the action that caused the effects. 8) Each affected resource, ecosystem, and human community must be analyzed in terms of its capacity to accommodate additional effects, based on its own time and space parameters. As required by HAR § 11-200.1-10, a group of actions proposed by an agency or an applicant shall be treated as a single action when: 1) The component actions are phases or increments of a larger total program; 2) An individual action is a necessary precedent to a larger action; 3) An individual action represents a commitment to a larger action; or 4) The actions in question are essentially identical and a single EA or EIS will adequately address the impacts of each individual action and those of the group of actions as a whole. The Hawaii Environmental Policy Act Citizen's Guide (2014) recommends that when considering the significance of potential environmental effects, the proposing or approving agency should consider the sum of the effects on the quality of the environment. A proposed action must be described in its entirety, and shall not be broken up into component parts, which if each is taken separately, may have minimal impact on the environment. An action shall be determined to have a significant effect on the environment if it may be individually limited but cumulatively have substantial adverse effect upon the environment or involves a commitment for larger actions. For example, pools or septic tanks or other ancillary or accessory structures/uses to a residence structure should be included in a larger development as a single action. According to Stormwater impact Assessments: connecting primary, secondary and cumulative impacts to Hawaii's Environmental Review process, May 2013, the methodology of cumulative impact assessments should address the following issues: 1) Cumulative effects need to be analyzed in terms of the specific resource, ecosystem, or human community being affected. 2) Cumulative effects on natural systems must use natural ecological boundaries. 3) Cumulative effects are caused by the aggregate of past, present, and reasonably foreseeable future actions. 4) Each affected resource, ecosystem, and human community must be analyzed in terms of its capacity to accommodate additional effects, based on its own time and space parameters. 0