BrightSource Energy, developer of the Ivanpah Solar Electric Generating System now under construction in the California desert, wants to change how it mitigates its project effects on the federally threatened desert tortoise. The company has filed a request last week to amend the project's permit with the California Energy Commission (CEC) allowing it to protect tortoise habitat elsewhere in the Mojave Desert rather than in the Ivanpah Valley, as the permit now requires.
The Ivanpah Solar Electric Generating System is being built on almost 4,000 acres of what was once prime desert tortoise habitat in the Ivanpah Valley, which straddles the California-Nevada line south of Las Vegas. Slated for completion in 2013, the 370-megawatt solar thermal project was briefly halted in 2011 when workers found hundreds more of the threatened reptile on the site than surveys had predicted.
As part of the required mitigation of the project's impacts on desert tortoise habitat, BrightSource agreed in 2010 to a number of land protection measures including either buying or acquiring conservation easements on att least 175 acres of desert wash habitat in the same watershed as the project. The company now says that the Ivanpah Valley doesn't have sufficient connected lands to make that feasible. BrightSource wants to be able to meet the project's mitigation requirements through the California Department of Fish and Game's Advance Mitigation Land Acquisition Grants (AMLAG) program, in which the agency acquires mitigation lands with funds paid into a state trust fund by project developers.
The portion of the Ivanpah Valley where Ivanpah SEGS is located is neither an Area of Critical Environmental Concern nor a designated or proposed Desert Wildlife Management Area, nor is it designated by the U.S. Fish and Wildlife Service as critical habitat for any species. With respect to cumulative impacts and related issues, the presence of 1-15, Nipton Road, the Primm Valley Golf Club, Primm itself, and the Union Pacific Railroad railway has not only permanently altered drainage patterns but, along with Ivanpah Playa itself, substantially fragmented desert tortoise habitat in Ivanpah Valley. These barriers also limit the value of the available private land parcels in the Ivanpah Valley due to their lack of potential to promote habitat connectivity.
The nearly 200,000-acre Ivanpah Valley actually offers a fair amount of potential connected tortoise habitat. It's true that some few thousand acres have been developed for Primm and its associated golf course, but those developments are clustered in a relatively small section in the central valley. Interstate 15 and the railroad line similarly disrupt connectivity between the east and west sides of the valley, but offer little obstruction to the north-south migration that will become especially crucial for tortoise survival as the globe warms.
Taking advantage of the AMLAG program would allow BrightSource to pay the state to protect land in other parts of the desert. BrightSource's petition to the Energy Commission identifies other areas in the Mojave that offer potential mitigation land opportunities:
Suitable lands have been identified within the Cady Mountain-Hidden Valley, Fremont-Kramer/Superior-Cronese, and Chuckwalla property groupings. These lands are located either within a proposed Desert Wildlife Management Area, or within a proposed Wilderness Area. Additionally, these lands are private parcels that currently fragment the proposed Desert Wildlife Management Area or Wilderness Area.
That's a laudable goal, though not one that does much to remedy any harms done to the Ivanpah Valley's tortoises, which U.S. Fish and Wildlife Service (FWS) studies indicate may have been genetically isolated for millennia from tortoises elsewhere in the California Desert. In February, in an assessment of the tortoise's status across its range, the FWS described the long-term geographic barriers that have caused Ivanpah Valley tortoises to evolve a unique genome:
Saline Valley and Death Valley extending south into Silurian Valley and Soda Dry Lake act as a barrier between this recovery unit and the Western Mojave Recovery Unit. Although gene flow likely occurred intermittently during favorable conditions across this western edge of the recovery unit, this area contains a portion of the Baker Sink, a low-elevation, extremely hot and arid strip that extends from Death Valley to Bristol Dry Lake. This area is generally inhospitable for desert tortoises.
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