Chapter 26 Cumulative Impacts The Council on Environmental Quality (CEQ) regulations for implementing the National Environmental Policy Act require the assessment of cumulative Words in bold impacts in the decision-making process for proposed federal projects. and acronyms are defined in Cumulative impacts are defined as the impact on the environment which Chapter 32, results from the incremental impact of the action when added to other past, Glossary and present, and reasonably foreseeable future actions regardless of what agency Acronyms. (federal or non-federal) or person undertakes such other actions (40 CFR 1508.7). As stated in the CEQ handbook, "Considering Cumulative Effects under the National Environmental Policy Act" (CEQ 1997), cumulative impacts should be analyzed in terms of the specific resource, ecosystem, and human community being affected and should focus on effects that are truly meaningful. This chapter provides an analysis of potential cumulative impacts related to the Proposed Action, the I-5 project. The analysis was accomplished using the following four steps: Step 1 - Identify Potentially Affected Resources Resources were identified that potentially could be cumulatively affected by the I-5 project when combined with other actions (see Section 26.1, Affected Resources and Resource Boundaries). Step 2 - Establish Boundaries Spatial (i.e., location) and temporal (i.e., time) boundaries were established for the consideration of other potentially cumulative actions (see Section 26.1, Affected Resources and Resource Boundaries). Step 3 - Identify Potentially Cumulative Actions Other past, present, and reasonably foreseeable future actions were identified that have contributed, or could contribute, to cumulative impacts on the resources identified in Step 1 (see Section 26.2, Cumulative Actions). These actions fall within the spatial and temporal boundaries established in Step 2. Step 4 - Analyze Cumulative Impacts For each resource, the actions identified in Step 3 were analyzed in combination with the impacts of the I-5 project. This analysis describes the overall cumulative impact related to each resource and the I-5 project’s contribution to this cumulative impact (see Section 26.3, Cumulative Impacts Analysis). 26.1 Affected Resources and Resource Boundaries To identify resources that could be cumulatively affected by the I-5 project and other actions (Step 1), BPA considered a large geographic area within the general vicinity of the project area and the likelihood that various other actions, with a wide range of potential effects on many I-5 Corridor Reinforcement Project Final EIS 26-1 Chapter 26 Cumulative Impacts resources, have taken or could take place within this area. Accordingly, BPA determined that all of the same resources described in the affected resource chapters in this EIS (see Chapters 5 through 22) should be considered in the cumulative analysis. BPA then established reasonable boundaries for the consideration of other past, present, and reasonably foreseeable future actions (Step 2). These boundaries are in terms of where the other actions are located (e.g., spatial boundaries), and when in time these actions took place or will take place (e.g., temporal boundaries). Accordingly, for each resource, the spatial boundary is the area where other past, present, and reasonably future actions have, are, or could take place and create cumulative impacts on the affected resource when combined with the impacts of the I-5 project. Appropriate spatial boundaries can vary for each resource; the boundaries identified for this analysis are described by resource (see Section 26.3, Cumulative Impacts Analysis). The temporal boundary describes how far into the past, and forward into the future, other actions should be considered in the cumulative impact analysis. For the purposes of this analysis, past and present actions that have shaped the landscape since about the first European settlement in the general vicinity (i.e., since about the early to mid 1800s) are considered, to the extent that they have had lasting effects contributing to cumulative impacts. The reasonably foreseeable nature of potential future actions helps define the forward-look temporal boundary. While BPA acknowledges that the proposed project could exist for 50 or more years and could contribute to cumulative impacts during that timeframe, it would be speculative to consider actions beyond what is reasonably foreseeable (see Section 26.2.2, Reasonably Foreseeable Future Actions). Given this limitation, the forward-looking temporal boundary has been established generally at about 10 years following the expected completion of construction of the proposed project, which is a reasonable timeframe by which the reasonably foreseeable future actions identified in Section 26.2.2 likely would be implemented. 26.2 Cumulative Actions After establishing appropriate spatial and temporal boundaries, BPA identified other past, present, and reasonably foreseeable future actions potentially contributing to cumulative effects along with the I-5 project (Step 3). To identify these other actions, BPA used information gathered in the course of developing the analysis of direct impacts related to the I-5 project, reviewed web posted project lists, and consulted various federal, tribal, state, local jurisdictions, and project sponsors. The following discussion provides more information on how potentially cumulative past, present, and reasonably foreseeable future actions were identified; and describes the cumulative actions that have been identified for the cumulative analysis in this EIS. 26.2.1 Past and Present Actions Past actions relevant to the cumulative analysis in this EIS are those that have previously taken place and are largely complete, but that have lasting effects on one or more resources that also would be affected by the I-5 project. For these past actions, CEQ has issued a guidance memo entitled "Guidance on Consideration of Past Actions in Cumulative Effects Analysis." This guidance states that consideration of past actions is only necessary in so far as it informs agency decision-making. Typically the only types of past actions considered are those that continue to have present effects on the affected resources. In addition, the guidance states that "[a]gencies 26-2 I-5 Corridor Reinforcement Project Final EIS Chapter 26 Cumulative Impacts are not required to list or analyze the effects of individual past actions unless such information is necessary to describe the cumulative effect of all past actions." Accordingly, agencies are allowed to aggregate the effects of past actions without "delving into the historical details of individual past actions." In this EIS, impacts from past actions are largely captured in the sections of each resource chapter that discuss the affected environment (see Chapters 5 through 22). Present actions are those that are currently occurring and also result in impacts to the same resources as would be affected by the I-5 project. Present actions generally include on-going land management and use activities (such as farming), and ongoing or recently completed residential, commercial, and industrial development. Similar to past actions, relevant present actions have largely been captured in Chapters 5 through 22 of this EIS. The following summarizes some of the more significant past and present actions in the general vicinity of the proposed project that have created cumulative impacts relevant to this analysis: Agricultural use—Beginning with European settlement in the early to mid 1800s, thousands of acres of land were converted from native prairie and floodplain to agriculture and pasture. These uses tend to be located in the flatter, lower elevation areas near the cities of Camas, Vancouver, and the Columbia River crossing. The conversion of undeveloped land to cropland largely stopped in the mid 1900s as most available and agriculturally suitable lands had already been converted. In recent years, as suburban development has expanded, agricultural land has been subdivided for residential development, reducing the amount of agricultural use. Timber clearing—European settlers also cleared native forest from thousands of acres for agricultural and other uses. Much of the tree clearing for agriculture took place on the flatter, lower elevation areas suitable for agriculture. In addition, as communities throughout the Lower Columbia River region were being developed in the late 1800s and early 1900s, nearby foothills and other wooded areas often were partially or fully cleared so trees could be used for houses, barns, fences, and other structures in and near these communities. Some cleared areas were allowed over time to revegetate and have become forested once again, while other areas were subsequently developed for other uses and remain occupied by these uses. Timber harvest—Over the years, large areas of native forest have been converted into timber stands managed for timber harvests. Timber harvest in the Lower Columbia River region began in the 1860s (NMFS and USFWS 2006); however, at that time, the general practice was to clear cut an area rather than actively manage it for ongoing production, as is more the standard practice today. Today, most lands managed for timber harvest in the general vicinity are in Cowlitz County. Additional timber lands are in the eastern part of Clark County. The large tracts of forest under timber harvest management in these counties exist in various age classes across