APPENDIX D MITIGATION FOR LOST HABITAT
TABLE OF CONTENTS
MITIGATION FOR LOST HABITAT D-1
D.1 MITIGATION STRATEGY D-1
D.2 HANFORD SITE MITIGATION STRATEGY D-2
D.3 MITIGATION PLANS FOR THE PREFERRED ALTERNATIVE D-2
APPENDIX D MITIGATION FOR LOST HABITAT
This appendix addresses the proposed mitigation strategy and its relationship to the site-wide mitigation program. Actions proposed as part of the alternatives would require clearing shrub-steppe habitat to construct new facilities. The part of that habitat dominated by mature sagebrush has been designated as a priority habitat by the State of Washington because of its importance to wildlife and because it is becoming relatively scarce in the state. Therefore, the loss of substantial acreage of this habitat type is an issue of concern for any alternative. Compensatory mitigation for unavoidable losses of this habitat, in the form of restored, enhanced, or newly established similar habitat, is planned. The following sections discuss mitigation strategy in general, mitigation strategy for the Hanford site, and mitigation plans for the preferred alternative.
D.1 MITIGATION STRATEGY
Such a mitigation requirement assumes that the restoration of sagebrush habitat or creation of favorable conditions for it on disturbed sites is feasible. Revegetation projects (including some on the Hanford Site) have successfully planted and established sagebrush. The possible approaches to mitigation range from seeding to planting nursery stock to transplanting mature shrubs. While each strategy has its advantages, each also has disadvantages. Seeding is the cheapest method for revegetating barren soil, but the length of time to achieve mature sagebrush is likely to be years, even decades. There are also many factors that can interfere with the success of a seeding effort, and some sites are less amenable to this approach than others. Planting nursery stock offers several advantages, including a higher likelihood of success, adaptability to a wide range of sites, and a slightly shorter time from planting to maturity than seeding. The costs are higher, and it may be necessary or desirable to establish a nursery nearby to optimize survival and use local genetic stock. Transplanting mature or near-mature plants from sites scheduled for construction would probably be the most expensive on a unit basis, and the techniques may be least proven; but the rewards could be substantial. Using this transplanting approach, it should be possible to establish habitat for wildlife species that require mature shrubs as a key component of the habitat. Transplanting would avoid the gap between the time of habitat loss and the time when replacement habitat is useable by a species of concern for which it is critical such as the loggerhead shrike.
D.2 HANFORD SITE MITIGATION STRATEGY
A Hanford site-wide mitigation strategy is being discussed by representatives of the DOE, their contractors, the WDFW, the USFWS, and other members of the Natural Resource Trustees Council. The development of the strategy is in a formative stage, with concepts and procedures for agreements being the initial focus. Under a site-wide mitigation strategy, there should be a substantial savings of time to all parties because the negotiations of mitigation details could be done once, rather than repeatedly for each separate project. The results should be more predictable and success more readily achievable, because each project would contribute an increment to a comprehensive study of the critical information needed to assure success rather than have to rely on a more limited study that would be economically feasible for one project. The site- wide strategy would also facilitate a broader landscape and ecosystem approach to mitigation than would be expected with separate project mitigation. Perhaps the most significant benefit would be to the habitat and the species that use it, because efforts would be focused on creating, enhancing, or revegetating habitat rather than on negotiations.
D.3 MITIGATION PLANS FOR THE PREFERRED ALTERNATIVE
Since a site-wide mitigation strategy has not yet been adopted and implemented, the mitigation for the clearing of mature sagebrush habitat for the RCSTS would necessarily be a stand-alone program. The concepts, developed more fully in the MAP, generally follow the mitigation approach described in the Draft EIS and apply the key elements of the draft site-wide mitigation strategy. The following are key components of the mitigation strategy: . Avoidance and minimization of impact through siting . Salvage and transplant . Restoration of temporarily disturbed habitat . Compensation for lost habitat. Each of these components are discussed in the following paragraphs. Measures to avoid and minimize impacts have been applied to the extent feasible. The anticipated loss of mature sagebrush has been reduced substantially since the Draft EIS was published. The construction corridor for the RCSTS would incorporate previously cleared roadways to reduce the width of the construction corridor from a nominal 30.5 m (100 ft) to 26 m (85 ft). Another means of minimizing the impact is that mature shrubs would be salvaged from the area to be cleared and planted in the enhancement area. Restoration of temporarily disturbed habitat could be an important feature of the mitigation program. It is anticipated that an average of 23 m (75 ft) of the RCSTS construction corridor could be restored, if there will be no need for further disturbance associated with the use of the RCSTS. However, if decommissioning of the RCSTS required removal of the pipes, the area would be disturbed again at the end of the useful life of the facility. About 8 ha (20 acres) of cleared sagebrush habitat could be restored in place and provide good potential habitat if the pipes can be left in place when decommissioned. In addition, about 0.6 ha (1.5 acres) of the corridor, now occupied by cheatgrass/rabbitbrush habitat, could be planted with sagebrush. The remainder must be kept clear of vegetation to prevent deep-rooted shrubs from drawing up contaminated material in the unlikely event a leak should occur. Since it is assumed that decommissioning of the RCSTS would require pipe removal, the method of restoration would be to add sagebrush seeds to a seed mixture of native grasses that would be sown on the disturbed areas. This combination will help prevent invasive plant species from excluding desirable native species. If tanks are built as part of the new storage alternative, some of the area disturbed for construction could also be similarly restored. Compensation for lost habitat values would be accomplished by enhancing the habitat value of an area west of the 200 West Area (see Figure 5-2) that has had no sagebrush component for many years due to past fires, but has the other components of a mature habitat (e.g., understory species). A baseline characterization of the proposed compensation area is included in the MAP. The compensation site area has also been surveyed for cultural resources to make sure the mitigation action would not affect cultural resources. Enhancement would be through restoration of the shrubs in a selected area of habitat. Compensation for lost habitat value (for up to 50 years) is to be done at a ratio of 3 ha (7.4 acres) of replacement for each 1 ha (2.5 acres) lost. Under the preferred alternative, 9 ha (23 acres) of mature sagebrush would be lost initially. As described in Section 5, at a ratio of 3:1, 28 ha (69 acres) would be replaced for this project. Of that, 9 ha (23 acres) would have mature sagebrush plants transplanted from the RCSTS corridor (salvaged prior to clearing of the corridor). These transplants would be placed at a density of 50 per ha (20 per acre) and will be supplemented with tubeling nursery stock at a density of 500 per ha (200 per acre). The remaining 18 ha (46 acres) would be planted with tubelings at a density of 750 per ha (300 per acre). If the new storage alternative is selected, the compensation would be done at the same ratio by expanding the proposed compensation area. To assure that the concerns of tribes and natural resource agencies are considered, the detailed mitigation plans for inclusion in the MAP are being prepared in consultation with interested members of the Natural Resource Trustees Council. Since potentially significant cultural resource sites have been identified in the 560 ha (1,300 acre), a specific plan for avoidance of these sites will be included in the MAP. Procedures to follow in the event of encountering other cultural resource sites will also be specified. Tribes and natural resource agencies will be given the opportunity to participate in mitigation activities to make sure that their concerns are adequately considered during implementation of the MAP.
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