12As discussed in Section 5.4.2 of the Draft Solar PEIS, areas available for application for

13solar energy development may overlap with BLM wild horse or burro HMAs. The management

14of these animals is not compatible with areas of solar development. Wild horses and burros

15would be displaced from the areas of solar energy development and, depending on the conditions

16of the HMA, it might be necessary to reduce the appropriate management level (AML; the

17maximum number of animals sustainable on a yearlong basis) to match forage availability on the

18remaining portions of the HMA. A reduction of AML could necessitate the gathering, care, and

19holding of animals in excess of the revised AML.

20

21Information provided in the Draft Solar PEIS remains valid; there are no updates for this

22section.

23

24

25 5.4.3 Wildland Fire

26

27Electrical substations associated with solar energy facilities present a potential fire hazard

28due to the modification of the voltage and current phase of the generated electrical power. In

29addition, any solar facility can indirectly create increased fire risk because of the operation

30of internal combustion vehicles and equipment in dry desert environments or if invasive

31species are allowed to become established within the facility’s footprint from improper

32vegetation management.

45Recreational use would be excluded from all areas developed for solar energy facilities,

46including areas currently designated for OHV use. There may also be adverse impacts on

1 recreational use of lands located nearby, including lands not administered by the BLM. Indirect 2 effects on recreational use would occur primarily on lands near the solar facilities and would

3result from the change in the overall character of undeveloped BLM-administered lands to an

4industrialized, developed area that would displace people who are seeking more rural or

28The impacts on recreation described in the Draft Solar PEIS omitted any discussion of

29recreational impacts that might be associated with the acquisition of mitigation lands acquired to

30offset losses to other resources caused by solar energy development. An example of this would

31be lands acquired for the mitigation of wildlife losses. Management of mitigation lands will be

32determined on a case-by-case basis, but mitigation lands likely would be managed primarily for

33the benefit of the resource for which they are acquired (e.g., endangered species habitat), and

34recreation and other uses likely would be considered secondary uses. The actual level of this

35secondary use would be dependent on the specific situation. Any losses of recreation or other

36uses (e.g., grazing) on mitigation lands would be considered in the environmental analysis of the

37project for which mitigation is required.

38

39

40 5.6 MILITARY AND CIVILIAN AVIATION

41

42Development of utility-scale solar facilities has the potential to affect both military and

43civilian aircraft operations, radar use, and airport operations. Numerous civilian airfields,

44military training routes (MTRs), and special use airspace (SUA) areas are located within the

45six-state study area. The military airspace in the study area is intensively used and is important

46to maintaining overall training and readiness for all branches of the military. Intrusion of solar

1 energy facilities into low-level airspace in military training areas and near military and civilian 2 airports can pose safety issues.

3

4 Information provided in the Draft Solar PEIS remains valid, with the following updates: 5

6• The discussion of potentially “displacing” sensitive species onto military

30As discussed in Section 5.7.1 of the Draft Solar PEIS, impacts on soil resources

31encompass a range of effects that would be expected to occur mainly as a result of ground-

32disturbing activities, especially during the construction phase of a solar energy project, regardless

33of the type of facility under development. Impacts include soil compaction, soil horizon mixing,

34soil erosion and deposition by wind, soil erosion by water and surface runoff, sedimentation, and

35soil contamination. These impacts could in turn affect other resources, such as air, water,

36vegetation, and wildlife.

4• Section 5.7.4 (Potentially Applicable Mitigation Measures) should include a

14Utility-scale solar energy development would be incompatible with most mineral

15development activities and would preclude these activities once solar energy facilities are

16constructed. An exception to this could occur if oil and gas or geothermal resources could be

17accessed under a solar energy facility utilizing offset drilling technologies. Existing valid mining

18claims, oil and gas leases, or other types of mineral leases would preclude or affect solar energy

19development.

34Impacts on surface water and groundwater resources from utility-scale solar energy

35development are primarily the result of stressors that include water use and surface disturbances,

36which can both impair water quality and limit water quantity. The information in Section 5.9 of

37the Draft Solar PEIS describes potential impacts from these stressors that could occur during the

38site characterization, construction, operation, and decommissioning phases, for the four utility-

39scale solar energy technologies evaluated.

40

41The information in Section 5.9 of the Draft Solar PEIS remains valid. The following

42paragraphs provide a summary and some additional information regarding the major potential

43impacts on water resources from solar energy development. It should be noted that Native

44American tribes may have concerns about the impacts on water discussed in the Solar PEIS, as

45brought to the attention of the BLM through recent ethnographic studies (SWCA and University

1 of Arizona 2011). Features of tribal importance identified during the studies included playas, 2 Pleistocene lakes and wetlands, rivers, washes, and springs.

3

4Water Management. Water use is one of the major issues with solar energy development,

5because all projects will require varying amounts of consumptive water use, and the regions

6 being considered are all in semiarid to arid desert valleys where water resources are limited. The 7 processes involved in obtaining water rights for solar energy development vary at the state and

8local levels, and most of the regions being considered for solar energy development are already

9fully allocated with respect to water rights. The transfer of water rights for solar energy

10development may result in land use changes, which would affect basin hydrology. For example,

11in the San Luis Valley in Colorado, the potential transfer of irrigation water rights for solar

12energy development would most likely result in a reduction of agricultural lands, along with a

13potential reduction in localized groundwater recharge that would have occurred below the

14agricultural field. In many regions in the six-state study area, groundwater basins are adjudicated

15such that there are restrictions in what water can be used for, along with restrictions on the

16magnitude, timing, and location of water withdrawals. All state and local water right and water

17management considerations must be examined at the project-specific scale; however, it is very

18likely that solar energy projects that seek low water use requirements through technology choices

19and water conservation measures will have a higher probability of successfully securing water

20rights.

21

22One of the main water conservation practices that can be used to reduce water demand

23is through the use of degraded water sources that include reclaimed municipal wastewater,

24produced water from oil and gas operations, and brackish groundwater. For example, the CEC

25discourages the use of freshwater sources for power plant cooling purposes for desert renewable

26energy projects. The CEC recognizes that in many regions in the desert southwest, groundwater

27quality can be brackish and not suitable for potable uses, and that these non-potable water

28sources should be considered first for operational water needs at solar energy facilities. Similar

29water conservation strategies have been developed in Arizona where the Arizona Department of

30Water Resources (ADWR) requires that the maximum amount of reclaimed wastewater be used

31for power plant cooling purposes (ADWR 2012). The potential use of degraded water sources,

32along with other water conservation practices, needs to be considered on a project-specific basis,

33because it is often the case that the needed infrastructure (e.g., pipelines to transport reclaimed

34wastewater) or technologies for water conservation are not in place. Several programs under the

35Bureau of Reclamation’s WaterSMART program should be considered by solar energy

36developers, along with state agencies and regulators, which include grants pertaining to the

37development of technologies, infrastructure, and conservation practices that include water and

38energy efficiency, advanced water treatment, and water reclamation and reuse (BOR 2012).

39

40Update for Section 5.9.1.2.2, Streams: Perennial, Intermittent, and Ephemeral. Surface

41disturbances associated with the solar facility footprint and related infrastructure have the

42potential to disturb natural hydrologic processes relevant to surface waters and groundwater. In

43desert valley regions, surface hydrologic features included intermittent and ephemeral stream

44channels, wetlands, alluvial fans, springs and seeps, playas, and dry lakebeds, which all have

45functional value to both surface water and groundwater resources. Grading of the surface and

46vegetation removal for solar facilities disturbs these water features and can affect groundwater

1 recharge processes, disrupt flows in ephemeral stream channels, and alter drainage patterns with 2 potential adverse impacts resulting from either an increase (e.g., erosion) or a decrease (e.g., loss

3of water delivery) in runoff. Ephemeral and intermittent streams represent more than 81% of all

4streams in the six-state study area, and their hydrologic and ecological significance has been

5 documented in several studies (e.g., Levick et al. 2008). Siting of solar energy facilities needs to 6 consider these important ecological and hydrologic functions of water features in desert valleys;

7however, it is not feasible to avoid all water features because of their ubiquitous nature in desert

8regions. Consideration of water features that require avoidance or mitigation needs to be

9 conducted on a project-specific basis and include stakeholder involvement, along with regulators 10 at the federal, state, and local levels.

11

12Federal laws such as the CWA will require a permitting process for any jurisdictional

13water bodies affected by a solar development. The determination of jurisdictional waters is made

14on a case-by-case basis by the USACE and EPA. Draft guidance regarding the identification of

15jurisdictional waters was proposed by the USACE and EPA in April 2011; the final version of

16the guidance has not yet been released. The draft guidance document suggests that the number of

17water bodies that would be jurisdictional would increase, but that jurisdictional determinations

18would still be handled on a case-by-case basis (EPA 2012). States can also have laws and

19management programs that aim to protect surface water features. The CDFG manages the Lake

20and Streambed Alteration Program, which is a permitting program like the CWA but specifically

21includes all water features, including intermittent and ephemeral water bodies (CDFG 2012). The

22Utah Division of Water Rights (Utah DWR) manages a stream alteration permitting program

23where a natural stream is defined primarily by patterned ecosystems, notably by vegetation

24patterns (Utah DWR 2004) that would typically include ephemeral water features.

25

26The protection of water resources from overuse and from surface disturbances requires

27the involvement of solar developers, land managers, and regulators at the federal, state, and local

28levels. Protection from water overuse is primarily dealt with in the securing of water rights,

29which varies at the state and local levels. It is often desirable to limit groundwater extractions in

30a basin to the sustainable yield, which has various definitions but is generally considered the

31withdrawal amount that does not produce any undesirable results. With such a generic definition,

32a variety of rules-of-thumb have been developed to quantify the sustainable yield of groundwater

33basins, such as limiting withdrawals to some fraction of the natural recharge. However,

34balancing the complex processes of groundwater recharge and capture (increased recharge and

35decreased discharge induced by pumping), the long temporal scales needed to achieve dynamic

36equilibrium conditions within a groundwater basin, and the potential for groundwater

37withdrawals to include water from surface water bodies (an undesirable result) makes

38quantifying a sustainable yield very challenging (Bredehoeft and Durbin 2009; Zhou 2009).

39Ultimately, the best way to prevent groundwater overdraft is through the iterative process of

40groundwater monitoring and numerical modeling to help guide adaptive management strategies.

41This is not an easy process to implement given that water right allocations, transfers, and

42adjudications often involve several management agencies and judicial systems. As stated

43previously, laws for protecting surface water features, primarily intermittent and ephemeral

44water bodies, are not fully established or implemented in a fashion that is suitable for considering

45potentially large surface disturbances in desert valleys. Land managers and stakeholders need to

46use all available information regarding the ecological and hydrologic functions of surface water