Addendum Palmdale Hybrid Power Project Biological Assessment

AMEC Earth & Environmental, Inc. (AMEC) is providing this Addendum to the Palmdale Hybrid Power Project Biological Assessment, Los Angeles County, California, March 2009 (BA) to clarify that construction and operation of the proposed Palmdale Hybrid Power Project (PHPP or Project) is not likely to adversely affect the federally threatened desert tortoise or federally endangered arroyo toad.

Desert Tortoise Pg. 19 – Replace the last sentence with the following: “Although there is suitable habitat on the north-south portion of transmission line segment 1 and the southeast portion of transmission line segment 2, with relatively uninterrupted habitat to the east, the lack of documented tortoise sightings closer than 12 miles away and the lack of observed sign on the Project surveys suggests that desert tortoise occurrence potential is low along these transmission line segments.”

Pg. 23 – Replace Section 5.2 paragraph 2 with the following: “It is highly unlikely that desert tortoises are present on the power plant site. Based on discussions with Dr. Alice Karl, a well-known desert tortoise expert, there is a low chance that desert tortoises are present along the north-south portion of transmission line segment 1 and the southeast portion of transmission line segment 2 (Karl 2008). Based on the survey results from two years of focused surveys, plus other data from hist oric and recent surveys and assessments, desert tortoise are presumed to be absent on the power plant site, reclaimed water pipeline, potable water pipeline, natural gas supply pipeline, and sanitary wastewater pipeline. The occurrence potential along the north-south portion of transmission line segment 1 and the southeast portion of transmission line segment 2 is considered to be low. Although the proposed

transmission line would result in the loss or disturbance of 26.84 acres of suitable habitat for the desert tortoise, this impact would be insignificant because: (1) desert tortoises are likely absent from this area; (2) based on the desert tortoise recovery plans (FWS 1994a, 2008) and critical habitat designation (FWS 1994b), FWS does not consider this area to be important to the recovery of the species; and (3) FWS has no plans to re-introduce desert tortoises in this portion of the desert. Also, in the unlikely event that a small number of desert tortoises remains in the area, the small amount of habitat loss and the dispersed nature of the loss would not impair the ability of these desert tortoises to find food and shelter. The Project therefore may affect, but is not likely to adversely affect, the desert tortoise.

Pg. 25 – Change Condition 7 to: “No tortoises will be handled during this Project. In the unlikely event that a tortoise is observed in a work area, it will be avoided and allowed to continue unimpeded. Work may halt in the immediate area of the tortoise, a temporary separation fence may be erected, or the tortoise may simply be monitored. The City will employ whatever measures are nec essary to ensure its safety.”

Pg. 25 – Remove last paragraph of Section 5.2 and insert the following text as Condition 10 regarding common raven measures:Although desert tortoises are absent from the power plant site and have low potential to occur along the transmission line route, desert tortoises occur within the area within the distance that common ravens can fly to obtain food and water. Project construction and operational activities could contribute to a regional increase in the common raven population, which could cause a regional increase in common raven predation on desert tortoise. The following avoidance measures w ill be implemented to reduce the Project’s likelihood of contributing to a regional increase in the common raven population. The goals of these avoidance measures are to: (i) educate Project staff about common raven and desert tortoise; (ii) reduce and preclude human-provided subsidies of food and water; and (iii) reduce common raven nest and communal roost sites (FWS 2008).

i. Training and Awareness Program The Project’s employee training and awar eness program for both the construction and operational phases of the Project will include education relative to common ravens. This program is intended to complement measures described in the FWS Common Raven Management Envir onmental Assessment (FWS 2008b).

During both the construction and operations phases of the Project, workers will participate in an environmental awareness training program that will provide information about the biology and status of the desert tortoise and the potential for juvenile predation by common ravens. Ensuring that the Project staff and contractors are properly trained and educated regarding common ravens and the potential for predation on tortoises is an important component of the long-term common raven minimization strategy for the Project. Day-to-day operational practices can greatly influence the potential for common ravens to obtain food, water, and other anthropogenic subsidies. Workers will be made aware of the importance of not leaving any food or water outside of the facilities for stray animals or pets. They will also be encouraged to not leave any potential sources of food (such as grain, fruit, etc.) in uncovered truck beds, flat-bed trailers or other accessible external locations

on their vehicles.

During the orientation session, Project staff and contractors will be provided instruction pertaining to proper trash disposal techniques and water minimization procedures, including minimizing standing water during construction. A brochure will be provided that summarizes specific positive actions that will be taken and those to avoid. Workers will also be provided with raven nest identification training and learn how to differentiate a raven nest from various raptor species. They will be encouraged to report roosting and nesting observation to a qualified Project biologist or the site environmental compliance officer (such observations will be augmented by those of biological monitors).

ii. Reduce/Preclude Human-Provided Subsidies of Food and Water To minimize the potential for food scavenging by common ravens, all outdoor trash cans at the Project facility will be raven-proof and equipped with self-closing lids or covers. An adequate number of these trash cans will be provided for employees and the general public at entrances and exits to the building and in parking lots. All large dumpsters at the facility will be equipped with tightly fitting lids.

It is anticipated that the greatest potential for providing unintended common raven water subsidies resulting from Project implementation may occur during the construction phase of the Project because water may be used for a variety ofpurposes such as compaction, dust abatement, hydrostatic testing, and other relatively short-term purposes. To the extent practicable, activities that may produce standing or ponded water will be minimized or avoided during construction. Temporary surface drainage improvements such as land grading or field ditches will be used to conduct water away from areas with standing water. Discharge areas for construction activities such as hydrotesting will be selected with adequate drainage.

Water truck fill locations will also be se lected in areas that drain well. If necessary, gravel will be laid down, or other tempor ary engineering solutions (such as a leach field) will be installed to ensure that water truck filling operations do not provide a

source of water for common ravens.

Construction staff will be instructed to minimize the use of water during the construction phase of the Project. During the operational phase of the Project, the environmental awareness training program described above will help ensure thatworkers minimize sources of surface water available to common ravens during dayto-day operations. Staff will also be encouraged to immediately report and repair leaking faucets and/or waterlines.

The Project design does not include any evaporation ponds, landscaping, or other readily available sources of surface wa ter that might serve as a common raven subsidy. In addition, the site grading plans and design of the facilities will minimize the potential for post-construction stormwater to pond on the site. Infiltration basins will be designed to remain dry between rainfall events, detain storm water no longer than 48 hours after rainfall events, and incorporate other engineering design features in accordance with Federal Aviation Administration guidance.

iii. Reduce/Preclude Common Raven Nest and Communal Roost Sites To the extent practicable, the power plant si te structures will be designed and built to incorporate elements that reduce the potential for use as common raven nest and roost sites ( e.g. , communication towers, billboards, and shade structures). Following construction, if a feature proves to be an especially attractive nesting or roosting location, it will be modified or equipped with non-harmful deterrent or repellent devices. Common deterrents include spikes, repellent coils, post and wire (control wire), netting, and electric shock systems. Should a raven nest be built on a power plant structure, it will be removed during the non-nesting season in consultation with CDFG and FWS. If an active raven nest is found on the power plant site or transmission line that has a dead desert tortoise in or beneath it, the Ventura U.S. Fish and Wildlife Office will be contacted immediately.

Arroyo toads – Replace Section 5.1 of the BA with the following.

Designated critical habitat for arroyo toads is located 2-3 miles south (upstream) of where transmission line segment 2 crosses Little Rock Creek. If arroyo toads are present in this critical habitat area, arroyo toads, larvae, and egg masses could potentially move downstream during years of favorable rainfall when water is present. However, the most recent recorded sighting was in 2001 (CDFG 2009), approximately three miles upstream from the Project’s proposed crossing of Little Rock Creek. To reach the transmission line crossing location, an arroyo toad individual, larva, or egg mass would need to navigate across Little Rock Reservoir and Little Rock Dam, which is highly unlikely.Focused breeding season surveys were conducted in 2009 in the Little Rock Creek area (where transmission line segment 2 crosses Little Rock Creek), and no arroyo toad adults, juveniles, eggs, or larvae were detected. Based on the intermittent flow at this location (drying out by early summer; dry throughout some years), marginal habitat (lack of suitable stream and burrowing substrate), and the absence of arroyo toads during 2009 focused surveys, it is highly unlikely arroyo toads utilize this section of Little Rock Creek and the Project therefore will have no effect on the arroyo toad. No additional avoidance and minimization measures (beyond what the Projec t is already proposing to avoid and minimize impacts to the Little Rock Creek Significant Ecological Area) are necessary.

References

Pg. 27 – Add the following reference:

United States Fish and Wildlife Service (FWS). 1994a. Desert tortoise (Mojave population) Recovery Plan. U.S. Fish and Wildlife Service, Portland, Oregon. 73 pp plus appendices.

---. 1994b. Final rule: determination of critical habitat for the Mojave population of the

desert tortoise. FR 59 (26):5820-5866.

---. 2008a. Draft revised recovery plan for the Mojave population of the desert tortoise ( Gopherus agassizii ). U.S. Fish and Wildlife Service, California and Nevada Region, Sacramento, California. 209 pp.

---. 2008b. Final Environmental Assessment to Implement a Desert Tortoise Recovery Plan Task: Reduce Common Raven Predation on the Desert Tortoise. Ventura,

California.