5.4 BIOLOGICAL AND ECOLOGICAL RESOURCES
This section describes the impacts of the TWRS EIS alternatives on biological and ecological resources. The impact assessment focused on the biological resources of the specific land areas where activities are proposed under the various EIS alternatives. All of the alternatives would have varying impacts on vegetation and wildlife habitat, especially shrub-steppe habitat. In all cases, the impacts would be less than 1 percent of the total remaining shrub-steppe habitat on the Central Plateau and a fraction of 1 percent of the Hanford Site's remaining shrub-steppe habitat. When considering only the area that would be designated for future waste management uses, the TWRS alternatives would impact up to 6 percent of the undisturbed shrub-steppe within the designated waste management area. For remediation activities impacts would range from 10 ha (25 ac) for the Long-Term Management alternative to 81 ha (200 ac) for the Phased Implementation alternative. Total alternative impacts (remediation and post-remediation closure actions) would add from 40 ha (100 ac) to 80 ha (200 ac) to the impacts from remediation. Most remediation impacts would occur in the 200 Areas, while post-remediation impacts would more heavily impact potential borrow sites, two of which are located outside the Central Plateau of the Hanford Site. All of the alternatives, expect No Action, Long-Term Management, and In Situ Fill and Cap, would result in noise and transportation impacts that would impact wildlife. None of the alternatives would adversely impact Hanford Site aquatic, wetland, or riparian habitats and none would impact Federal or State threatened or endangered species. Potential impacts to other species of concern would be limited to a relatively small portion of the overall habitat.
Following the end of the remedial phase of each alternative, exposure to waste under the No Action and Long-Term Management alternatives likely would be fatal for wildlife. Direct exposure to waste would pose a fatal risk under the In Situ Fill and Cap, In Situ Vitrification, and Ex Situ/In Situ Combination 1 and 2 alternatives; however, the likelihood of exposure would be minimal. Direct exposure under the remaining ex situ alternatives, though considered unlikely, would pose a risk to wildlife. No other exposure scenario (e.g., contaminated groundwater at seeps along the Columbia River) under any of the alternatives would pose a substantial risk to wildlife.
For this analysis, the key issues are 1) whether the land areas proposed for use currently are undisturbed or whether they have been disturbed by past activities; 2) the extent of potential impacts on sensitive shrub-steppe habitat, which is considered a priority habitat by Washington State; and 3) potential impacts on plant and animal species of concern (those listed or candidates for listing by the Federal government or Washington State as threatened, endangered, and sensitive). The section also describes impacts to three potential borrow sites that would be associated with the tank closure scenario included for the comparative analysis of the alternatives.
Activities for all tank waste alternatives except No Action would occur at locations that contain both undisturbed and disturbed land. For example, the tank farms and their immediate surrounding areas currently are heavily disturbed and thus have minimal native vegetative or wildlife habitat. The vitrification facility sites in the 200 East Area associated with the various ex situ alternatives and the Phased Implementation alternative contain currently disturbed land that is of minimal habitat value and undisturbed shrub-steppe that is considered valuable as vegetative and wildlife habitat. The amount and location of the land areas required by each alternative are described in Section 3.0 and Volume Two, Appendix B. The analysis of potential impacts on species of concern focused on plant and animal species found in the Hanford Site's shrub-steppe habitat.
Where TWRS alternatives' activities are proposed in areas that are partly disturbed and partly undisturbed habitat, the alternatives' vegetation and wildlife habitat impacts were calculated proportional to the current percentage of disturbed versus undisturbed land at the particular site. For example, if 30 ha (70 ac) were required at a site that currently is 50 percent disturbed, the habitat impact was calculated to be 15 ha (30 ac) (30 ha [70 ac] times 50 percent). No attempt was made to lay out or configure facilities to either maximize or minimize habitat impacts. Final design, configuration, and layout of facilities for alternatives selected for implementation would incorporate habitat impact avoidance and minimization as part of the development process. However, none of the alternatives are far enough along in the design process for this to have occurred.
5.4.1 Impacts to Vegetation
Virtually all proposed TWRS activities under all EIS alternatives would occur on the Hanford Site's Central Plateau within or between the 200 East and 200 West Areas. All TWRS sites are within shrub-steppe habitat. There are approximately 8,500 ha (21,000 ac) of shrub-steppe on the Central Plateau. This area is approximately 15 percent of the total remaining shrub-steppe habitat of the Hanford Site. All alternatives except No Action would have varying degrees of impact on vegetative habitat (Figure 5.4.1 and Table 5.4.1). In all cases, the affected shrub-steppe area would be less than 1 percent of the total remaining shrub-steppe on the Central Plateau and a small fraction of 1 percent of the Hanford Sites total shrub-steppe habitat.
Table 5.4.1 summarizes the potential shrub-steppe habitat impacts of the TWRS alternatives and identifies the plant species of concern that potentially would be affected. Table 5.4.1 provides a comparison of the potential impacts of each alternative based on where the impacts would occur (200 Areas or at potential borrow sites) and the impacts of the remedial phase of the project compared to impacts of the total alternative (remediation and the post-remediation closure scenario activities). The table also summarizes the total impacts of the alternatives and lists the species (vegetation and wildlife that potentially could be impacted by the alternatives).
Under all alternatives except No Action, approximately 13,000 m (33,000 ft) of replacement underground pipelines would be constructed at various locations in the 200 Areas. All pipelines would be placed in currently disturbed areas adjacent to the existing pipelines. Therefore, there would be no impact on shrub-steppe habitat.
5.4.1.1 Tank Waste Alternatives
No Action Alternative (Tank Waste)
The No Action alternative would involve no additional construction and thus no additional land disturbance. Consequently, there would be no impacts to shrub-steppe habitat.
Long-Term Management Alternative
As shown in Table 5.4.1, the Long-Term Management alternative would impact approximately 10 ha (25 ac) of undisturbed area in the 200 East Area. The undisturbed area that would be affected is shrub-steppe habitat characterized by big sagebrush or gray rabbitbrush, both native plant species typical of the shrub-steppe community. This area would be used for constructing replacement DSTs for existing storage tanks that have reached the end of their design lives, as well as for power lines to provide electrical power to the new tank farms and for a new evaporator. Plant species potentially impacted include the crouching milkvetch, stalked-pod milkvetch, and scilla onion, all Washington State Class 3 monitor species, and Pipers daisy, a species that is listed as sensitive by Washington State.
Figure 5.4.1 Habitat Impacts of Tank Waste and Capsule Alternatives
This alternative also would impact approximately 14 ha (35 ac) of shrub-steppe habitat at the potential Pit 30 borrow site. No Federally listed plant species would be affected, but the stalked-pod milkvetch, a Washington State Class 3 monitor species, and Pipers daisy, a State sensitive species, have been observed there and would be affected (Duranceau 1995).
In Situ Fill and Cap Alternative
The In Situ Fill and Cap alternative would affect no undisturbed vegetative habitat in the 200 Areas. However, because remediation would involve filling all 177 tanks with gravel from the potential Pit 30 borrow site , 23 ha (57 ac) of vegetation would be disturbed at Pit 30 (located on the Central Plateau between the 200 East Area and the 200 West Area).
During closure activities, approximately 17 ha (42 ac) of shrub-steppe would be disturbed at the potential Vernita Quarry borrow site. The area that would be affected is undisturbed shrub-steppe habitat with varying degrees of shrub coverage, primarily big sagebrush, rigid sagebrush, and some spiny hopsage, as well as grasses such as Sandbergs bluegrass and bluebunch wheatgrass. No Federally-listed threatened or endangered species would be affected. Two plant species classified as Class 3 monitor species by Washington State were observed in 1993 biological surveys and would be affected. These are the stalked-pod milkvetch and crouching milkvetch (Duranceau 1995).
This alternative also would disturb approximately 12 ha (30 ac) of shrub-steppe at the potential McGee Ranch borrow site and 13 ha (32 ac) at the potential Pit 30 borrow site during closure activities. No Federally-listed threatened or endangered species would be affected at McGee Ranch, although the crouching milkvetch and the scilla onion, two Washington State Class 3 monitor species, were identified there in 1993 biological surveys and would be impacted (Landeen et al. 1994). No Federally-listed threatened or endangered plant species would be impacted at Pit 30, although the stalked-pod milkvetch, a Washington State Class 3 monitor species, and Pipers daisy, a State sensitive species, have been observed there (Duranceau 1995).
In Situ Vitrification Alternative
The In Situ Vitrification alternative would disturb 23 ha (57 ac) of undisturbed shrub-steppe habitat by constructing 115-kilovolt (kV) transmission lines to the tank farms in the 200 Areas where the in situ vitrification activities would occur (Figure 5.4.1). The acreage at and around the tank farms where the vitrification facilities would be developed currently is disturbed. An additional 18 ha (44 ac) would be disturbed at the potential Pit 30 borrow site during remediation activities.
During closure activities, the In Situ Vitrification alternative also would disturb approximately 42 ha (100 ac) of shrub-steppe at the three potential borrow sites (17 ha [42 ac] at Vernita Quarry, 12 ha [30 ac] at McGee Ranch, and 13 ha [32 ac] at Pit 30). Impacts would be similar to the In Situ Fill and Cap alternative.
Ex Situ Intermediate Separations Alternative
During tank waste remediation, this alternative would impact about 59 ha (150 ac) of shrub-steppe habitat in the 200 East Area and 33 ha ( 82 ac) at the potential Pit 30 borrow site. During closure activities, this alternative would impact an additional 77 ha (220 ac) of shrub-steppe at the three potential borrow sites ( 23 ha [62 ac] at Vernita Quarry, 13 ha [47 ac] at McGee Ranch, and 41 ha [110 ac] at Pit 30). The same impacts described for the Long-Term Management and In Situ Fill and Cap alternatives would be impacted under this alternative.
Ex Situ No Separations Alternative
This alternative would have similar vegetation impacts to the Ex Situ Intermediate Separations alternative. However, during remediation, the Ex Situ No Separations alternative would impact more shrub-steppe in the 200 Area (approximately 89 ha [ 220 ac]) than the Ex Situ Intermediate Separations alternative (approximately 33 ha [ 82 ac]) because of the need for interim storage of large quantities of vitrified waste before offsite shipment to the potential geologic repository. During closure, less borrow material, and therefore less habitat disturbance, would be required at the potential borrow sites for this alternative than for the Ex Situ Intermediate Separations alternative (Table 5.4.1).
Ex Situ Extensive Separations Alternative
During remediation, similar activities would take place at the same proposed waste processing site and for closure at the same potential borrow sites, as discussed for the other ex situ alternatives. The Ex Situ Extensive Separations alternative would disturb the same amount of shrub-steppe habitat as the Ex Situ Intermediate Separations alternative (Table 5.4.1).
Ex Situ/In Situ Combination 1 Alternative
During remediation, this alternative would impact about 56 ha (140 ac) of shrub-steppe habitat in the 200 East Area and 32 ha ( 79 ac) at Pit 30. For closure activities, a total of 58 ha ( 140 ac) of additional shrub-steppe habitat would be impacted at the three potential borrow sites ; (21 ha [52 ac] at Vernita Quarry, 12 ha [30 ac] at McGee Ranch, and 25 ha [ 62 ac] at Pit 30).
Ex Situ/In Situ Combination 2 Alternative
This alternative would impact 40 ha (100 ac) of shrub-steppe habitat in the 200 Areas during remediation as well as 30 ha (75 ac) at Pit 30. For closure activities, an additional 48 ha (120 ac) of shrub-steppe would be affected at the three potential borrow sites; 19 ha (47 ac) at Vernita Quarry, 11 ha (27 ac) at McGee Ranch, and 18 ha (44 ac) at Pit 30.
Phased Implementation Alternative
Phase 1
Phase 1 of the Phased Implementation alternative would disturb about 21 ha ( 52 ac) of shrub-steppe vegetation in the easternmost section of the 200 East Area. Approximately 1 ha (2 ac) of shrub-steppe would also be disturbed at the potential Pit 30 borrow site to support remediation activities. The same kind of plant species identified for the other alternatives would be impacted by this alternative.
Total Alternative
The Phased Implementation alternative, when fully implemented, would result in a total disturbance that would include the impacts identified for Phase 1, as well as impacts associated with implementing Phase 2 construction, retrieval, operations, and post remediation for the entire alternative. The total impacts would include 99 ha ( 240 ac) of shrub-steppe habitat in the 200 Areas and 37 ha (49 ac) in the potential Pit 30 borrow site associated with remediation activities. An additional 81 ha (200 ac) of shrub-steppe habitat would be disturbed at the three potential borrow sites resulting from closure activities. The same kind of plant species impacted under the other alternatives would be impacted by this alternative.
5.4.1.2 Capsule Alternatives
The No Action alternative essentially would have no vegetation impacts because no new land disturbance would occur. All other cesium and strontium capsule alternatives would have minor impacts on vegetation. The Onsite Disposal alternative would involve constructing a disposal facility on the Central Plateau just west of the 200 East Area, which would impact approximately 1.5 ha (3.7 ac) of shrub-steppe. The Overpack and Ship and the Vitrify with Tank Waste alternatives would involve additional minor facility development within areas that would be disturbed by the vitrification complex proposed in the 200 East Area for the Ex Situ Intermediate Separations alternative. Thus, no additional vegetation disturbance would be associated with these capsule alternatives.
5.4.2 Wildlife
Under all tank waste alternatives except No Action, some loss of individual members of wildlife species would occur. However, when considering the total Hanford Site population of the affected species, the number of individual members lost is not expected to be large enough to have substantial impact on any species as a whole. As described previously, activities in currently undisturbed areas would affect wildlife habitat, while activities in currently disturbed areas would not affect wildlife habitat. The impact analysis focused on impacts in undisturbed wildlife habitat areas.
The EIS alternatives would impact wildlife by directly disturbing habitat areas at proposed facility sites. Rodent and rabbit populations of the disturbed areas would be destroyed or displaced. This would impact raptor species (birds of prey such as harriers, kestrels, hawks, and owls) and mammals (such as coyotes, badgers, mule deer) of the Central Plateau and vicinity. Predator food supplies would decrease, which would in turn increase competition and decrease predator species productivity. Eventually, this would result in a local reduction in the predator population of the Central Plateau as individual species members died or were displaced. Common bird species (e.g., larks and finches) would be displaced and ground nesting birds such as the killdeer and mourning dove could be affected by the destruction of nests. Impacts would affect only individual members of the species; they would not be of a scale to affect the Sitewide populations of either the predator species or nonpredator species.
In addition to direct impacts from habitat loss, the increased levels of human activity and associated noise for all tank waste alternatives (except No Action) would displace wildlife species, particularly raptors and predatory mammals. The noise impacts would occur primarily from using heavy equipment during facilities construction and at borrow sites, although the general disturbance caused by increased human presence would continue throughout facility operations. Predators would likely move out of the immediate area, which would further contribute to competition for food and living space in adjacent areas. Construction noise levels would approach background levels at distances greater than 600 m (2,000 ft), and the zone of indirect impact would vary by species. However, the overall zone of impact for some species could extend to a radius of up to 800 m (2,700 ft) from the construction site (Section 5.9).
Increased vehicular traffic associated with the various alternatives also could lead to occasional collisions between vehicles and wildlife. This could lead to a slight increase in mortality of various wildlife species, including large mammals such as mule deer. The levels of increased mortality would be directly proportional to the employment levels and associated traffic volumes for each alternative (Section 5.10).
The nesting period is a critical time period for most bird species. Disturbances, including noise, could result in nest abandonment and declines in productivity. Nesting disturbances of raptors such as the ferruginous hawk, swainsons hawk, red-tailed hawk, and prairie falcon could occur at distances greater than 800 m (2,700 ft). For example, the Pacific Northwest National Laboratory recommends confining human activity to the nonnesting season or avoiding alteration or disturbance within 1.0 km (0.6 mi) of red-tailed hawk nests, 1.6 km (1.0 mi) of ferruginous hawk nests, and 1.5 km (0.9 mi) of swainsons hawk nests (PNL 1994e). The only likely potential raptor nesting site in the 200 Areas would be on power transmission facilities. Construction of new power lines for the alternatives could provide additional raptor nesting sites. Passerine (songbird) species such as the sage sparrow also could be adversely affected by disturbance during the breeding season. Avoiding activities such as Site clearing during breeding or avoiding disturbance near songbird nesting areas would reduce these impacts.
Under all tank waste alternatives except No Action, there would be approximately 13,000 m (33,000 ft) of replacement underground pipelines placed in currently disturbed portions of the 200 Areas. As these pipelines would be placed in currently disturbed areas adjacent to the existing pipelines, no wildlife impacts would be expected.
Impacts associated with the closure phase of the alternatives would 1) include habitat loss at the potential McGee Ranch borrow site, which would be used under all tank waste alternatives except No Action and Long-Term Management; and 2) adversely affect an important wildlife corridor between the Hanford Site and the Yakima Training Center, which are the two largest remaining shrub-steppe habitat areas in Washington State. Disturbing this corridor would contribute to fragmenting the region's shrub-steppe habitat. The corridor potentially is of importance to medium-to-large mammals, such as coyote, deer, and elk, and to other species using relatively undisturbed shrub-steppe. The corridor is generally important from the standpoint of species proliferation and maintaining genetic diversity. The corridor also has the potential for serving as a conduit for the reintroduction to the Hanford Site of sage grouse, a State and Federal candidate species. Sage grouse were displaced from the Site by a major wildfire in 1984. The nearest population of sage grouse is at the Yakima Training Center, and the McGee Ranch provides the most direct, relatively undisturbed corridor between the Site and the Yakima Training Center.
Table 5.4.1 summarizes the shrub-steppe habitat impacts of the TWRS alternatives and identifies wildlife species of concern that potentially may be affected.
5.4.2.1 Tank Waste Alternatives
No Action Alternative (Tank Waste)
The No Action alternative would involve no additional land disturbance and thus would have no impacts on wildlife resources.
Long-Term Management Alternative
The Long-Term Management alternative would disturb approximately 10 ha (25 ac) of shrub-steppe wildlife habitat in the 200 East Area from retanking the DSTs. An additional 14 ha (35 ac) of shrub-steppe habitat would be affected at the potential Pit 30 borrow site. Potentially affected species would include the horned lark, western meadowlark, common raven, red-tailed hawk, ferruginous hawk, violet green swallow, great basin pocket mouse, and northern pocket gopher. Impacts, which would be limited to individual members of species, would be small when considering the Hanford Site as a whole.
Two species of concern are found at the potential Pit 30 borrow site in addition to the species identified in the 200 East Area. These are the loggerhead shrike (Federal and State candidate species) and the sage sparrow (State candidate species). Both species nest and raise their young in shrub-steppe, and the habitat disturbance would adversely impact both the shrike and sparrow.
In Situ Fill and Cap Alternative
During remediation, the In Situ Fill and Cap alternative would affect only currently disturbed lands in the 200 Areas (Table 5.4.1). These areas at and near the tank farms are of little wildlife habitat value. During remediation, there would be 23 ha (57 ac) impacted at the potential Pit 30 borrow site.
During closure, activities at the potential Vernita Quarry borrow site would affect wildlife by disturbing about 17 ha (42 ac) of shrub-steppe habitat. Potentially affected species and impacts would be those identified for the Long-Term Management alternative, as well as mule deer, coyote, and badger, which all are found in the vicinity. A pair of red-tailed hawks was observed nesting on the basalt cliff face at Vernita Quarry during a 1994 biological survey. Such nesting activity would be disrupted if the hawks were present during the post-remediation Hanford Barrier construction phase of the project (Duranceau 1995).
Similar bird and mammal species would be affected at the potential McGee Ranch borrow site where 12 ha (30 ac) of shrub-steppe wildlife habitat would be disturbed. Individual species members would be lost or replaced, but only small impacts would occur on the species as a whole. However, the McGee Ranch area is an important corridor between the Hanford Site and the Yakima Training Center. Two species of concern found at McGee Ranch would be affected: the loggerhead shrike (Federal and State candidate species) and the sage sparrow (State candidate species). Moreover, the reintroduction to the Hanford Site of the sage grouse, a Federal and State candidate species, could be adversely affected.
During closure activities, wildlife impacts would be similar at the potential Pit 30 borrow site to those at the potential McGee Ranch and Vernita Quarry borrow sites. This is because essentially the same bird and mammal species are found in the shrub-steppe at Pit 30, although Pit 30 does not have the same importance as a wildlife corridor as McGee Ranch. However, the same adverse impacts on the sage sparrow and loggerhead shrike (Federal and State candidate species) would occur at Pit 30 as at McGee Ranch. Approximately 13 ha (32 ac) of additional shrub-steppe wildlife habitat would be impacted at Pit 30 during closure activities.
In Situ Vitrification Alternative
During remediation activities, this alternative would disturb approximately 23 ha (57 ac) of shrub-steppe habitat by constructing power lines to the tank farms in the 200 Areas and 21 ha (52 ac) of shrub-steppe habitat at the potential Pit 30 borrow site (Table 5.4.1). During closure, an additional 42 ha (100 ac) of shrub-steppe habitat would be disturbed at all three potential borrow sites (Table 5.4.1). Wildlife impacts at the potential borrow sites would be the same as described for the In Situ Fill and Cap alternative.
Ex Situ Intermediate Separations Alternative
During remediation, this alternative would disturb 57 ha (150 ac) of shrub-steppe wildlife habitat in the 200 East Area and 33 ha (59 ac) of shrub-steppe habitat in the potential Pit 30 borrow site. For closure activities, an additional 77 ha (220 ac) would be disturbed at the three potential borrow sites. Impacts would be the same as described for the In Situ Fill and Cap alternative.
Ex Situ No Separations Alternative
This alternative would involve wildlife impacts similar to the Ex Situ Intermediate Separations alternative. There would be more shrub-steppe wildlife habitat (96 ha [240 ac]) disturbed than for the Ex Situ Intermediate Separations alternative in the 200 Areas and at Pit 30 during remediation, with 89 ha (220 ac) of the disturbance occurring at Pit 30 (Table 5.4.1). There would be less disturbance at potential borrow sites during closure for this alternative than for the Ex Situ Intermediate Separations alternative because there would be no LAW vaults (64 ha [160 ac]).
Ex Situ Extensive Separations Alternative
This alternative would have impacts similar to the Ex Situ Intermediate Separations alternative because the same activities would occur at the same sites. The wildlife habitat acreage impacted would be less than for the Ex Situ Intermediate Separations alternative (Table 5.4.1).
Ex Situ/In Situ Combination 1 Alternative
During remediation activities, this alternative would disturb approximately 56 ha (140 ac) of shrub-steppe wildlife habitat in the 200 East Area and 32 ha (77 ac) of shrub-steppe habitat at the potential Pit 30 borrow site. An additional 58 ha (160 ac) of shrub-steppe habitat would be disturbed at the three potential borrow sites (21 ha [52 ac] at Vernita Quarry, 12 ha [ 30 ac] at McGee Ranch, and 25 ha [64 ac] at Pit 30) to support closure of the tank farms and LAW vaults. Impacts would be similar to those described for the Ex Situ Intermediate Separations alternative.
Ex Situ/In Situ Combination 2 Alternative
During remediation, this alternative would disturb 40 ha (99 ac) of shrub-steppe habitat in the 200 East Area and 30 ha (74 ac) at the potential Pit 30 borrow site. During closure, an additional 48 ha (120 ac) would be disturbed at the three potential borrow sites; 19 ha (47 ac) at Vernita Quarry, 11 ha (27 ac) at McGee Ranch, and 18 ha (44 ac) at Pit 30. Impacts would be similar to those described for the Ex Situ Intermediate Separations alternative.
Phased Implementation Alternative
Phase 1
Phase 1 of the Phased Implementation alternative would disturb approximately 21 ha (49 ac) of shrub-steppe wildlife habitat, all but 1 ha (2.5 ac) of which would be in the 200 East Area. Impacts similar to those described for the Ex Situ Intermediate Separations alternative would be expected.
Total Alternative
The Phased Implementation alternative, when fully implemented, would result in a total disturbance that would include the disturbances identified for Phase 1, as well as disturbances associated with implementing Phase 2. The total disturbances would include 79 ha (150 ac) of shrub-steppe habitat in the 200 Areas and 37 ha (91 ac) at the potential Pit 30 borrow site would be associated with remediation activities. An additional 81 ha ( 200 ac) at the three potential borrow sites would be associated with closure activities. Impacts to wildlife similar to those described for the Ex Situ Intermediate Separations alternative would be expected.
5.4.2.2 Capsule Alternatives
Wildlife impacts from all capsule alternatives would be negligible. The No Action (Capsules) alternative would disturb no additional wildlife habitat. The Onsite Disposal alternative would involve an area currently partly disturbed, and only 1.5 ha (3.5 ac) of wildlife habitat would be affected. Both of the other capsule alternatives would involve developing small facilities within the proposed complex for vitrifying tank waste. Thus, no additional wildlife habitat areas would be disturbed, and no incremental impacts would occur.
5.4.3 Aquatic, Wetlands, and Riparian Habitats
The aquatic habitats on the Hanford Site include the Columbia River, two small spring-fed streams on the Fitzner Eberhardt Arid Lands Ecology Reserve, and artificial ponds and ditches located in or near the 200 Areas. The primary wetlands on the Hanford Site are the riparian areas along the Columbia River. There also are human-made wetlands near the 200 East Area. None of the aquatic habitats, riparian areas, or wetlands would be directly or indirectly adversely affected by any EIS alternative.
5.4.4 Species of Concern and Critical Habitats
Impacts of all EIS alternatives on plant and animal species of concern were directly related to the amount of disturbance of shrub-steppe habitat associated with each alternative (Table 5.4.1). Species of concern are defined as those species 1) listed as threatened or endangered by the Federal government or Washington State; 2) identified as candidates for listing by the Federal government; or 3) identified as candidate, monitor, or sensitive species by Washington State. Critical habitats are habitat types that are of high value to wildlife, declining in abundance, or both.
No Federal- or State-listed species would be impacted by any EIS alternative. The following Federal candidate species or Washington State candidate, monitor, or sensitive species either were observed in TWRS EIS biological surveys or are known to exist in shrub-steppe habitat, and thus should be considered potentially impacted:
- Plant species - Crouching milkvetch, stalked-pod milkvetch, scilla onion, and Pipers daisy;
- Bird species - Loggerhead shrike, sage sparrow, ferruginous hawk, swainsons hawk, sage thrasher, long-billed curlew, prairie falcon, golden eagle, and burrowing owl;
- Mammal species - Pygmy rabbit; and
- Reptile species - Northern sagebrush lizard, striped whipsnake, and desert night snake.
Washington State considers shrub-steppe a priority habitat because of its value to many wildlife species and because it is a diminishing resource that is relatively scarce in the state. It is DOE policy at the Hanford Site to mitigate losses of mature sagebrush in shrub-steppe habitat areas. Section 5.20 contains additional details on mitigation of impacts to shrub-steppe habitat.
The western sage grouse, a Federal and State-listed threatened species, was found on the Site until the local population was displaced by a major wildfire in 1984. The bald eagle, also listed as threatened by the Federal government and Washington State, winters along the Hanford Reach. The bald eagle forages on fish and wildlife along the river. Eagles are not known to use the Central Plateau of the Site, which is 10 km (6 mi) or more from the river. Although the bald eagle potentially could consume fish from areas of the river that received groundwater contaminated under TWRS EIS alternatives, contaminant exposures to the bald eagle would be expected to be below levels of concern (Section 5.4.6). Thus, no direct or indirect impacts would be expected under any TWRS EIS alternative.
5.4.5 Biodiversity
The destruction or degradation of the shrub-steppe habitat on the Hanford Site would impact the area's unique biodiversity. None of the EIS alternatives would affect more than a fraction of 1 percent of the Hanford Site's total shrub-steppe area. However, impacts on the McGee Ranch area, a potential borrow site under all tank waste alternatives except No Action and Long-Term Management, would impact a wildlife corridor that is important for species migration, proliferation, and genetic diversity. Historic evidence at the Hanford Site indicates that disturbing shrub-steppe habitat leads to the incursion of exotic species that replace or compete with the native species. These new species tend to simplify the ecosystem, thereby reducing diversity and changing the ecological character of the Hanford Site. The impacts of EIS alternatives would be directly related to the amount of shrub-steppe they would disturb. Table 5.4.1 lists the differences in impacts among alternatives.
There are a variety of other ecosystems on the Hanford Site such as wetlands, riparian areas, and bluffs. These support unique plant and animal communities and contribute to the Hanford Site's biodiversity. None of the EIS alternatives would adversely affect any of the other Hanford Site ecosystems.
5.4.6 Radiological and Chemical Impacts to Biological and Ecological Resources
This section describes risk to plant and animal species from possible exposures to radionuclides and hazardous chemicals under the various EIS alternatives. Radiation doses and chemical hazards were assessed for a generic plant, several mammals (great basin pocket mouse, coyote, and mule deer), and two bird species (red-tailed hawk and loggerhead shrike). The methodology for this assessment is described in Volume Three, Appendix D. Calculation methods used were for the analysis similar to those described in the Hanford Baseline Risk Assessment Methodology (DOE 1995c). The equations were modified to follow the unit risk factor approach used for the human health assessment (Section 5.11).
5.4.6.1 Tank Waste Alternatives
No Action Alternative (Tank Waste) and Long-Term Management Alternative
Direct contact with stored waste is unlikely as long as institutional controls are present, but would be possible after the 100-year institutional control period. If direct contact with the waste occurred under the No Action and Long-Term Management alternatives, that exposure would be estimated to lead to potential radiation doses ranging from 16 to several million radiation absorbed doses (rad)/day, which most likely would be lethal to wildlife in a short time. The chemical hazards of direct exposure would range as high as several hundreds of times higher than the 1.0 hazard index that is the benchmark for potential adverse ecological impacts (e.g., a hazard index greater than 1.0 indicates adverse effects in ecological receptors of concern). The mechanism by which direct contact could occur many years in the future (after institutional control has been lost) would involve the eventual collapse of the top of an underground tank. This would allow species to fall into the exposed tank and suffer trauma from the fall as well as radioactive and chemical exposures. Birds would be the most likely animal to be impacted.
Exposure to routine air emissions under this alternative is estimated to result in radiation exposures of less than 1.0E-06 rad/day. Routine air emissions would occur only during the period of institutional control. This exposure level is far below background levels and would be expected to have no detectable effects on exposed species.
Exposure to contaminated groundwater reaching the Columbia River would result in low radiological exposure levels. Radiation doses would not approach the International Atomic Energy Agency 0.1-rad/day benchmark for terrestrial organisms or the National Council on Radiation Protection and Measurement 1.0-rad/day benchmark for aquatic organisms (IAEA 1992 and NCRP 1991).
The No Action and Long-Term Management alternatives are the most conservative of the alternatives evaluated and represent the greatest potential impact to groundwater and the Columbia River. This is because no remediation would be performed, and all the waste would remain in the tanks and be available for migration to groundwater following tank failure.
Under these alternatives, maximum chemical concentrations calculated to reach the Columbia River 300, 500, 2,500, 5,000, or 10,000 years in the future would result in maximum hazard indices well below the hazard index criterion of 1.0 for the indicator species (coyote, mule deer, red-tailed hawk, and loggerhead shrike). The ecological hazards were based on a conservative scenario involving consumption of groundwater contaminants at the point where groundwater reaches the surface on the Columbia River bank (e.g., springs or seeps) and assume no dilution of the groundwater contaminants by the river before access by the receptors. This scenario conservatively assumes that a terrestrial receptor would obtain all its water from a spring where maximum contaminant concentrations are calculated to occur. Further, this receptor is assumed to spend its entire lifetime drinking water from this single, maximum exposure location and nowhere else. In reality, all indicator species used to evaluate potential groundwater consumption are highly mobile and have relatively large home ranges, such that they would drink water at numerous locations both onsite and offsite. Based on the conservative nature of the exposure scenarios, the estimated hazards for the representative species indicate that no adverse effects would be expected for any terrestrial or aquatic receptor consuming groundwater in the future.
In Situ Fill and Cap Alternative
Under the In Situ Fill and Cap alternative, all of the tank waste would remain in place. As long as institutional controls were present, it is unlikely that ecological receptors would have direct contact with the tank waste. Following the loss of institutional controls, if direct contact with the waste occurred, that exposure would lead to potential radiation doses that most likely would be lethal to ecological receptors. Doses would be similar to those calculated for the No Action and Long-Term Management alternatives. The chemical hazards of direct exposure would range as high as several hundred times above the 1.0 benchmark for potential adverse ecological impacts.
For the In Situ Fill and Cap alternative, closure would entail placing a multi-layered Hanford Barrier over each tank farm. This 4.5-m (15-ft)-thick barrier would be designed to inhibit intrusion by burrowing animals. Consequently, direct contact with tank waste would be unlikely following closure.
Potential radiation doses as a result of radiological releases to air from routine operations would be below the 0.1-rad/day benchmark. Radiation doses from contaminated groundwater also would be below the 0.1-rad/day and 1.0-rad/day benchmarks for terrestrial and aquatic organisms, respectively. The maximum chemical concentrations calculated to reach the Columbia River under the No Action alternative represent the highest potential concentrations of groundwater contaminants for any of the alternatives. As described previously for the No Action alternative, maximum calculated contaminant concentrations in groundwater would result in hazard indices well below the hazard index criterion of 1.0 for all indicator species (coyote, mule deer, red-tailed hawk, and loggerhead shrike). Because chemical concentrations that would reach the Columbia River would be approximately 10 times lower under the In Situ Fill and Cap alternative than under the No Action alternative, potential chemical exposures would not pose a threat to terrestrial or aquatic receptors under the In Situ Fill and Cap alternative.
In Situ Vitrification Alternative
Under the In Situ Vitrification alternative, direct contact with the stabilized waste-containing material would result in radiation doses that most likely would produce lethal effects in ecological receptors. Following closure and construction of a Hanford Barrier over each tank farm, direct contact with the stabilized waste would be unlikely because this barrier is intended to prevent penetration by burrowing animals.
Estimated radiation doses resulting from routine air emissions would not exceed the 0.1-rad/day benchmark of concern (IAEA 1992). Exposure to contaminated groundwater reaching the Columbia River would be well below the 0.1-rad/day and 1.0-rad/day benchmarks for terrestrial and aquatic species, respectively. As described previously, maximum chemical concentrations calculated to reach the Columbia River under the No Action alternative would represent the highest potential concentrations of groundwater contaminants for any of the alternatives. Because the maximum hazard indices under the No Action alternative would be below the hazard index benchmark value of 1.0, chemical concentrations that would reach the Columbia River under the In Situ Vitrification alternative would not pose a threat to terrestrial or aquatic receptors.
Ex Situ Intermediate Separations Alternative
Under the Ex Situ Intermediate Separations alternative, 1 percent of the tank waste would remain as residual contamination. Direct contact with this residual tank waste would result in radiation doses that would pose a threat to ecological receptors, including potential lethal effects. Following closure and construction of a Hanford Barrier, direct contact with the 1 percent residual waste would be unlikely because this barrier is intended to prevent penetration of burrowing animals.
The maximum estimated radiation exposure from air releases during routine operations would exceed the 0.1-rad/day benchmark of concern under conservative assumptions. Exposures would range from 1.0 rad/day for the mule deer to 48 rad/day for the pocket mouse, primarily due to releases of carbon-14, cesium-137, and strontium-90. However, this estimate assumes year-long exposure at the location of maximum radionuclide concentrations. At other locations, radionuclide concentrations would be lower, and thus exposures would be lower. Species exposure to harmful levels of airborne radiation from routine releases would be unlikely unless an animal spent its entire life at the point of maximum exposure.
As described previously, maximum contaminant concentrations calculated to reach the Columbia River under the No Action alternative would represent the highest potential concentrations of groundwater contaminants of any of the alternatives. Because the maximum hazard indices and radiation doses under the No Action alternative were below their respective benchmark values (e.g., a hazard index of 1.0, 0.1 rad/day for terrestrial species, and 1.0 rad/day for aquatic species), groundwater contaminant concentrations that would reach the Columbia River under the Ex Situ Intermediate Separations alternative would not pose a threat to terrestrial or aquatic receptors.
Ex Situ No Separations Alternative
Radiological and chemical hazards to animal species for this alternative would be similar to those described for the Ex Situ Intermediate Separations alternative. However, direct contact radiological risk would be lower than for the Ex Situ Intermediate Separations alternative because there would be no long-term onsite storage of LAW. Maximum estimated radiation doses resulting from routine releases would be expected to exceed the 0.1-rad/day benchmark for terrestrial receptors. Given the conservative nature of this exposure scenario (i.e., year-long exposure at the point of maximum radionuclide concentration), it is unlikely that ecological receptors would be exposed to harmful levels of airborne radiation from routine releases under the Ex Situ No Separations alternative.
As described previously, maximum contaminant concentrations calculated to reach the Columbia River under the No Action alternative would represent the highest potential concentrations of groundwater contaminants of any of the alternatives. Because the maximum hazard indices and radiation doses under the No Action alternative would be below their respective benchmark values (a hazard index of 1.0, 0.1 rad/day for terrestrial species, and 1.0 rad/day for aquatic species), groundwater contaminant concentrations that would reach the Columbia River under the Ex Situ No Separations alternative would not pose a threat to terrestrial or aquatic receptors.
Ex Situ Extensive Separations Alternative
Radiological and chemical risk to animal species would be similar to those described for the Ex Situ Intermediate Separations alternative. Exposure mechanisms would be similar to the Ex Situ Intermediate Separations alternative but there would be less risk from LAW vaults because the concentration of radionuclides would be less in the LAW disposed of onsite. Maximum estimated radiation doses resulting from routine releases would be expected to exceed the 0.1-rad/day benchmark for terrestrial receptors. Given the conservative nature of this exposure scenario (i.e., year-long exposure at the point of maximum radionuclide concentration), it is unlikely that ecological receptors would be exposed to harmful levels of airborne radiation from routine releases under the Ex Situ Extensive Separations alternative.
As described previously, maximum contaminant concentrations calculated to reach the Columbia River under the No Action alternative would represent the highest potential concentrations of groundwater contaminants for any of the alternatives. Because the maximum hazard indices and radiation doses under the No Action alternative would be below their respective benchmark values (a hazard index of 1.0, 0.1 rad/day for terrestrial species, and 1.0 rad/day for aquatic species), groundwater contaminant concentrations that would reach the Columbia River under the Ex Situ Extensive Separations alternative would not pose a threat to terrestrial or aquatic receptors.
Ex Situ/In Situ Combination 1 and 2 Alternatives
These alternative s would be combination s of the In Situ Fill and Cap alternative for those tanks left in place and the Ex Situ Intermediate Separations alternative for the tank waste retrieved. The radiological and chemical constituents and concentrations released during operations would be similar to the In Situ Fill and Cap and the Ex Situ Intermediate Separations alternatives.
Under the conservative maximum exposure scenario, the maximum estimated radiation doses from air releases during routine operations would not exceed the 0.1-rad/day benchmark for terrestrial receptors.
As described previously, maximum contaminant concentrations calculated to reach the Columbia River under the No Action alternative would represent the highest potential concentrations of groundwater contaminants of any of the alternatives. Because the maximum hazard indices and radiation doses under the No Action alternative would be below their respective benchmark values (a hazard index of 1.0, 0.1 rad/day for terrestrial species, and 1.0 rad/day for aquatic species), groundwater contaminant concentrations that would reach the Columbia River under the Ex Situ/In Situ Combination 1 and 2 alternative s are not expected to pose a threat to terrestrial or aquatic receptors.
Phased Implementation Alternative
Phase 1
Phase 1 of the Phased Implementation alternative would include constructing one LAW processing plant and one combined LAW and HLW facility to process a portion of the tank waste. The chemical and radiological constituents and concentrations released during operations of this alternative would be similar to the Ex Situ Intermediate Separations alternative, and the associated impacts would be similar to operations. This phase of the alternative would not include disposal, so no post-remediation impacts would occur.
Total Alternative
The Phased Implementation alternative would result in chemical and radiological releases during operation, as described previously for Phase 1, and during operations associated with implementing Phase 2. The total chemical and radiological releases during operations and post remediation would be similar to those of the Ex Situ Intermediate Separations alternative.
5.4.6.2 Capsules Alternatives
Radiological and chemical risk to animal species would be small for all capsule alternatives. Neither the No Action alternative nor the Onsite Disposal alternative would involve waste treatment activities, and thus no radiological or chemical hazards would occur. Furthermore, no airborne releases would be expected from routine operations. Groundwater risk would be small because of the radioactive decay of the cesium and strontium capsule contents. By the time any releases could reach groundwater, only stable progeny isotopes (i.e., barium-137 and zirconium-90) would remain. The concentrations of these progeny in the groundwater would result in doses below the levels that would cause toxic effects in animal species.
It is conceivable that burrowing animals could be affected under the Onsite Disposal alternative after institutional controls were lost in the future. For example, pocket mice and burrowing owls could be stressed as a result of the heat generated from the capsules. Direct contact with the capsule contents also could occur following failure of the capsules. However, some radioactive decay of the cesium and strontium capsules likely would have occurred by the time of possible direct contact. Potential heat stress or direct contact impacts would affect a small number of individual species members and would have no impact on the total species population of the Site as a whole.
The Overpack and Ship alternative would involve no waste treatment and no long-term onsite storage of the capsules. No chemical or radiological risk to species would be expected.
The Vitrify with Tank Waste alternative would involve low risk to species. Capsule contents would be processed together with the tank waste in the same manner and at the same facility as described for the Ex Situ Intermediate Separations alternative. The vitrified capsule contents would be shipped offsite for disposal as HLW, and thus there would be no long-term onsite capsule waste storage.
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