The effects three solar plants on California grasslands


Monday, Sep. 07, 2009
Tribune special report: Valley of life
Though the Carrizo Plain may look like a desolate, inhospitable landscape, the remote grasslands are actually home to California’s largest concentration of endangered species, many of which live in underground burrows and are very rarely seen
By David Sneed | dsneed@thetribunenews.com

To the motorist passing on Highway 58, California Valley can look like a whole lot of nothing — brown flatlands nearly devoid of vegetation and inhabited by the occasional cow or raven.

If you’re lucky, you can catch sight of a pronghorn antelope or tule elk grazing in the distance.

But to the trained eye of a biologist like John Davis, the valley is full of signs of a vibrant wildlife community living in the state’s last remnant of grassland. Many of the animals live underground in this treeless environment, coming out only at night.
Click image to see caption

Biologists from URS Corp. — a Santa Barbara-based construction consulting firm — walk in lines while conducting a survey for blunt-nosed leopard lizards on SunPower’s Carrizo Plain site.

Of all the effects the three solar plants will have on the environment of the area, none are as significant as the wildlife impacts.

“Wildlife is the big issue,” said San Luis Obispo County Supervisor Jim Patterson, whose district includes the Carrizo Plain.

“The projects cover so much ground,” he added. “One of the major characteristics of the Carrizo is the multiple rare and endangered species found there.” The Carrizo Plain is the last remnant of grassland in the state.

The solar companies and the state Energy Commission are taking a coordinated look at wildlife issues. The effort has sparked controversy — the solar companies want some of the results of the study kept confidential because it may identify which lands they must purchase as mitigation and that could drive prices up.

Looking for lizards

Davis recently led a team of 24 biologists who were surveying a portion of the area that is proposed to be the site of SunPower’s California Valley Solar Ranch along the valley’s eastern edge.

SunPower hired Davis’ employer, URS Corp., a Santa Barbara-based construction consulting firm, to survey the more than three square miles on which the company will build the plant. One day recently, the URS team went looking for blunt-nosed leopard lizards, one of more than 70 rare and endangered animals that live in the area.

None were found — just as none of the lizards have been found on the other two proposed solar sites. But lots of other rare animals have been seen, including burrowing owls, San Joaquin kit foxes, coast horned lizards, the San Joaquin coachwhip snake and kangaroo rats.

Davis thinks the absence of the lizard is due to the fact that the valley is a marginal habitat for them. This site will be surveyed 12 times before biologists are satisfied that none live there.

“You can’t rule them out just because the habitat is marginal,” he said. “That’s why we do these presence/absence surveys.”

The biologists form a line, each person about 100 feet apart. They begin to walk. Occasionally, one stops to examine a hole in the ground or peer through binoculars at the landscape ahead.

The first thing that stands out is that the ground is full of holes. The holes range from large ones where kit foxes have made their dens or badgers have tunneled after ground squirrels to ones so small you could barely insert a pencil where pocket mice have made their dens.

But the most impressive are kangaroo rat dens — complexes, really. They feature numerous holes, both horizontal and vertical, leading to a network of tunnels. Areas of barren dirt mark where the rats have taken dust baths to eliminate parasites.

Some areas are covered with brown vegetative mats where the rats store red brome seeds, their burrs knitted together to prevent them from blowing away. The ground is also pockmarked with small pits where other grass seeds are stowed.

Davis stoops to measure the diameter of the holes. Biologists are uncertain exactly which species of kangaroo rat is making the holes — the endangered giant kangaroo rat or its more diminutive and more common cousin, the Heermann’s variety.

Before European Americans settled California, much of the Central Valley was covered with massive expanses of grass that hosted numerous herds of deer, antelope and elk.

Those grasslands were converted to farms and oil fields. Only the Carrizo Plain was spared because it lacked enough oil and water to be commercially viable.

This last fragile grassland remnant is so ecologically valuable that President Bill Clinton established the Carrizo Plain National Monument in the waning hours of his presidency in 2000 to protect it.

California Valley, comprising the plain’s northern end, was not included because it had been the most intensely farmed and is where the area’s few residents live.

Fox habitat

Of the myriad of rare species that survive in the Carrizo Plain, none is as important as the endangered San Joaquin kit fox. Populations of the little canine are scattered from the Carrizo northwest into Monterey County and Camp Roberts.

Ensuring that the three proposed solar plants do not block the fox’s migration routes, destroy den habitat or otherwise reduce its chances for survival will be the biggest challenge faced by the solar companies and state and federal wildlife managers.

“The kit fox is what we call an umbrella species,” said Dave Hacker, a state environmental scientist based in San Luis Obispo, who is monitoring wildlife issues associated with the solar farms. “If you can meet the conservation needs of the kit fox you can meet the needs of the other species in the area.”

Unfortunately, the proposed solar farms sit smack dab in the middle of the fox’s migration routes, as well as those of tule elk and pronghorn antelope. Because the fox is federally listed as endangered, its conservation needs far outweigh those of the elk and antelope.

Clearing a pathway

The two sprawling photovoltaic plants will have the biggest potential impact on the fox. Consequently, the companies say they have designed their projects to be as fox-friendly as possible.

Steps they plan on taking include raising the solar panels some 18 inches off the ground to allow the fox to move through the area and maintain a clear line of sight in order to avoid predators.

They plan to provide fencing around the plants that will allow the fox passage. Both photovoltaic plants have also scrapped plans to use concrete pedestals as foundations for their panel arrays in favor of sinking the foundation poles a short way into the ground.

Wildlife officials say this arrangement maximizes visibility for the fox. Not having to mix concrete also reduces water consumption.

Because the wildlife impacts are so important, the state Energy Commission has hired the consulting firm South Coast Wildlands to perform a wildlife corridor study that will look at the cumulative impacts of all three solar plants, said John Kessler, the commission’s Carrizo Plain project manager.

“The goal of this study is to provide and maintain an equivalent alternate corridor for wildlife as is utilized currently, considering the proposed project effects,” he said.

In spite of these efforts, the three solar plants will inevitably destroy or degrade wildlife habitat. The standard way to offset those impacts is to permanently conserve alternative habitat to replace it.

Ausra has options to purchase six square miles of nearby land to offset the environmental impact of its one-square-mile proposed solar thermal plant.

Similarly, SunPower is planning to use only about three square miles of the nearly seven square miles it has acquired, with the rest available for wildlife mitigation. First Solar has reduced the footprint of its project by 2,000 acres which would be available for wildlife mitigations.

The commission hopes to have the corridor study complete sometime this fall. The state Department of Fish and Game will then use the information to decide mitigation measures each plant must undertake.

“Wildlife cannot be worse off after these projects are built,” Hacker said. “That can be a challenge when you are looking at large-scale projects like these.”

Secret info?

The possibility that the solar companies will have to purchase additional land for wildlife mitigation has generated a controversy. The solar companies have requested that parts of the study be kept confidential.

They are afraid that if the study identifies certain properties for mitigation, the price of those properties could increase.

“This type of volatility could potentially have a negative impact on corridor mitigation activities, the interests of local landowners and the advancement of development of solar energy projects,” said Ausra spokeswoman Katherine Potter in a prepared statement.

California Valley residents are fighting the confidentiality effort as unnecessary. They say that property owners in the area are already well aware of the solar projects and would take them into consideration if they received any purchase offers.

Confidentiality would also limit public participation in the study, which has been valuable in increasing its accuracy, opponents say. A decision on the request is pending.

Reach David Sneed at 781-7930.

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