1(Quinn et al. 2006; Swaddle and Page 2007; Leonard and Horn 2008; Parris and

2Schneider 2008; Schaub et al. 2008; Slabbekoorn and Ripmeester 2008;

3Francis et al. 2009; Barber et al. 2010; Chan et al. 2010: Halfwerk et al. 2011;

4Lackey et al. 2011). Some wildlife species shift their vocalization to reduce

5masking effects (Barber et al. 2010). For birds, this can include singing earlier in

14Utility-scale solar energy facilities that would be constructed and operated have the

15potential to affect aquatic biota and habitats. Section 5.10.3.1 of the Draft Solar PEIS provided

16an overview of the potential impacts on aquatic ecosystems that could occur from site

17characterization, construction, operation, and decommissioning of a solar energy project. Impacts

18on aquatic biota and habitats from solar energy projects could occur in a number of ways,

19including (1) habitat loss, alteration, or fragmentation; (2) disturbance and displacement of

20aquatic organisms; (3) mortality; and (4) increase in human access. Aquatic biota and habitats

21may also be affected by human activities not directly associated with a solar energy project or its

22workforce, but associated with the potentially increased access by the public to areas that had

23previously received little use.

24

25The impact descriptions provided in the Draft Solar PEIS remain valid; however, the

26following updates for the construction and operations development phases have been added in

27response to comments received on the Draft Solar PEIS.

28

29

305.10.3.1.1 Construction. The impact descriptions provided in the Draft Solar PEIS

31remain valid, with the following update.

385.10.3.1.2 Operations. During the operations and maintenance phase of a utility-scale

39solar energy facility, aquatic habitats and aquatic biota may be affected by water withdrawn from

40aquatic habitats for cooling purposes, continued erosion and sedimentation due to altered land

41surfaces, exposure to contaminants, and continued increases in public access. The impact

42descriptions provided in the Draft Solar PEIS remain valid; however, a discussion of the

43potential impacts of polarized light and an expanded discussion of the impacts of water

44withdrawal on aquatic biota are being added, as follows.

45

1Recently, concern has been expressed about the impacts of polarized light on aquatic

2insects. Water bodies have the ability to polarize light. Consequently, light that has been

3 polarized by reflecting off smooth dark surfaces, such as solar panels, can act as an “ecological 4 trap” in which aquatic insects mistake solar panels for open water and lay eggs on the surface of 5 the panel (Horváth et al. 2009). In fact, insects can be more attracted to the highly polarized light

6reflected off solar panels than they are to natural water bodies (Horváth et al. 2010). Although

7high numbers of insects may be killed in this way, the significance of the resulting waste of

8 reproductive effort on insect populations is unknown, as is the potential for adverse impacts on 9 higher trophic levels that depend on these insects as food sources.

10

11If the solar energy technology used by a particular project requires water for producing

12steam for driving turbines or for cooling the produced steam during operation, there is a potential

13for water depletion impacts on aquatic habitats within the vicinity. Changes in the flow patterns

14of streams and the depletion of surface water resulting from surface or groundwater withdrawal

15could affect the quality of aquatic habitats and the survival of populations of aquatic organisms

16within affected bodies of water. For example, prolonged or frequent drying can reduce species

17diversity (McCluney and Sabo 2011; Datry 2011) and ultimately alter or eliminate species

18through physiological stress or habitat loss (Stanley et al. 1994; Sponsellor et al. 2010). In the

19case of aquatic invertebrates, the most sensitive species (i.e., Hydrosychidae) would be replaced

20by more tolerant species such as Chironomidae and Oligochaetae (Stanley et al. 1994;

21Sponseller et al. 2010). A reduction in water depths can also increase the susceptibility of some

22fish species to predation from avian and terrestrial predators. In intermittent habitats, water

23withdrawal could reduce the frequency and duration of wet periods, which could ultimately

24increase fragmentation of stream networks as streams become pools connected by dry reaches. In

25addition to a spatial and temporal reduction in available aquatic habitat, the water quality of the

26remaining habitat could decrease as temperature and solute concentrations increase and dissolved

27oxygen levels decrease. With regard to water quality, aquatic organisms have specific

28physiological tolerances within which survival is possible. Under natural conditions, many

29aquatic species in arid aquatic habitats may be at their physiological limit and an increase in

30stressful water quality conditions could significantly alter species composition

31(Stanley et al. 1994; Lake 2003; Archer and Predick 2008). In addition to stress or mortality at

32the level of the individual, water withdrawals could reduce genetic diversity as populations were

33eliminated by habitat loss or were reproductively isolated by habit fragmentation (Larned 2010;

34McCluney and Sabo 2011). Extinction of local populations under natural conditions can take

35longer than 5 years to recover (Lake 2003).

36

37Water depletions are of particular concern if protected species would be affected because

38the potential for negative population-level effects for rare organisms would be greater than for

39common and widespread organisms. Thus, water withdrawal concerns are particularly relevant in

40aquifers supporting endangered species. Many endangered aquatic biota exist in relatively few

41populations or are naturally endemic to a particular spring. For example, the Devils Hole pupfish

42(Cyprinodon diabolis) is endemic to Devils Hole, a spring-fed pool in Death Valley NP.

43Populations of the Devils Hole pupfish underwent significant declines beginning in the 1960s in

44response to water withdrawals for irrigation (Riggs and Deacon 2002).

45

46