(Editor’s note: The Valley Journal continues its series of stories exploring the various impacts of potential natural gas development in the Thompson Creek area near Carbondale.)

CARBONDALE, Colorado – Natural gas drilling is not easy on wildlife.

Colorado Division of Wildlife officials have seen both indirect effects leading to population declines and direct mortality in wildlife, in areas of intensive natural gas drilling. John Broderick, DOW senior terrestrial biologist for the Northwest Region, said if and when intensive drilling comes to the Thompson Creek area where several gas leases have been sold, the impacts will be unmistakable.

The greatest direct mortality to wildlife related to natural gas drilling is in waterfowl, Broderick said. Ducks will land in reserve pits or production pits at drilling pads. Reserve pits are used during the drilling process, and contain drilling mud, water and substances used in hydraulic fracturing of underground rock to free trapped gas. Production pits contain produced water, the water that comes to the surface with gas. That water is likely to contain oily hydrocarbons and toxic substances such as benzene.

“We’ve had mortality associated with both those types of pits,” Broderick said.

Sometimes waterfowl are coated with oily substances. Sometimes these birds can be cleaned by hand and saved. Other times they just die.

“Usually, they die from respiratory failure,” Broderick said.

Elk calves and deer sometimes get into reserve pits or production pits, too, in their search for water, Broderick said.

Randy Hampton, public information officer for the Colorado Division of Wildlife in the Northwest Region, said it’s hard to establish the cause of death in wildlife.

“Unless we find an animal dead next to a reserve pit,” Hampton said, “it’s difficult to determine pathologies.”

But the cumulative indirect impacts of gas drilling have a bigger overall effect on wildlife populations, Broderick said.

“The insidious and long-term effects are right there,” he said.

Gas drilling and the construction of roads to serve gas wells bring a level of disturbance and habitat fragmentation to wildlife habitat that many animals simply can’t tolerate.

In mule deer and elk, disturbance of this type may cause only slight apparent stress in herds in the near term, but can bring significant population declines over time.

“With increased stress, we see decreased survivorship,” Broderick said.

“We talk about how to minimize stressors,” he said. “But if you can’t minimize you have to mitigate.” Sometimes it falls to the DOW to find and rehabilitate some land elsewhere to provide similar habitat, to try to bring populations back to previous levels.

Raptors subject to stress

Game animals aren’t the only ones subject to stress from disturbance. Raptors — hawks, owls and eagles — are especially vulnerable, Broderick said.

You don’t have to physically knock down a raptor nest to prevent a pair of birds from breeding, he said. Industrial activity too near the area where the pair is involved in courtship behavior may discourage mating. And stress can cause the adult birds to abandon eggs or even young. The loss of a breeding season reduces population over time.

Roads are a big factor in the decline of deer and elk populations. Roads reduce the size of areas of unbroken habitat, which is especially harmful in elk calving areas like the aspen groves in the Thompson Creek area, Broderick said.

Spruce fir forest, which occurs in large unbroken stands, especially on north slopes in the Thompson Creek area, is good thermal cover — it provides shelter from wind and cold for elk — and hiding cover, he said. Fragmentation of those areas reduces the number of elk they can shelter.

Roads and the gravel platforms that support gas wells also increase runoff — less water is absorbed by the soil, and with the runoff, silt and toxic chemicals are carried to streams. This can be especially true in areas with steeper terrain.

Roads and other construction that disturbs native vegetation also invite another problem.

“You get noxious weeds anywhere the vegetation is disturbed, and that takes away from forage,” Broderick said. “That’s one of those unknown factors that cumulatively has a significant impact.”

Moreover, roads invite use by recreational drivers, who also have negative effects, including the increase of roadkill, Broderick said.

“Increased access results in increased disturbance, and you get more poaching and other illegal activities,” he continued.

Scientific evidence scarce

The indirect effects of gas drilling, and the roads and disturbance it brings, are hard to quantify, wildlife officials concede. But Colorado is learning from studies being done in gas fields in the Pinedale Anticline area in Wyoming, relating to mule deer and sage grouse. (Sage grouse are not in the Thompson Creek area.)

In Wyoming, scientists have learned to this point, that while a density of one gas well per square mile has minimal effects on mule deer populations, 16 wells per square mile is over the threshold for that species, showing a detrimental effect on populations. Broderick said the exact threshold level is yet to be determined.

Hampton said without exact science, it’s often hard to influence decisions on drilling made by other public agencies such as the BLM.

“On a permit application, if we’re going to comment, we try to bring a reason for protections to the table,” he said.

“People often put the DOW in a very tough position,” he continued, “where they say the DOW should come in and stop this drilling. But we have to take a scientific approach.”

Fish populations can also be affected by natural gas drilling. All three branches of Thompson Creek — North, Middle and South — have populations of native Colorado River Cutthroat Trout, said Ken Neubecker, president of the state council of Trout Unlimited.

“The biggest danger to the fishery is the same thing that threatens terrestrial wildlife,” Neubecker said. The roads built to serve drilling pads, the same roads that fragment deer and elk habitat, also threaten trout streams.

“Any trout populations could be severely impacted by sediment in runoff from roads and drilling pads,” said Neubecker, a Carbondale resident.

Sediment fills in all the spaces between the individual gravel stones that line mountain streams. Those spaces are where the primary food of trout, aquatic insects, live. The sediment buries and smothers the insect larvae among the stones, Neubecker said.

A second threat from sediment is to the spawning process. Trout lay their eggs in redds, shallow basins hollowed out in the gravel. After the eggs are fertilized, the female sweeps the eggs into the spaces between the stones, where they will remain until they hatch. After hatching, the tiny young remain mixed with the gravel until they are old enough to feed.

If sediment coats the stream bottom during this time, the brood will be smothered, Neubecker said.

Spills also threaten fish

Another threat to trout populations posed by gas drilling is spills of industrial materials or toxic chemicals. Spills from tanker trucks and leakage from holding ponds happen frequently.

Materials often involved in accidental spills are fluids used in hydraulic fracturing operations (which can vary from benign to toxic), drilling muds, or produced water. Produced water, which comes out of a gas well during or after drilling, can often contain hydrocarbon chemicals or other toxic impurities, and is usually stored in ponds near the wellhead.

Drilling mud, used to lubricate the drill bit during drilling, sounds harmless, Neubecker said. But it often contains a mineral called bentonite, which tends to add a fine-grained coating to whatever it touches.

“You get a bunch of that in a stream and it would be like lining a pond with concrete,” Neubecker said.

A spill of some toxic hydrocarbon substance would be even worse, he said, especially at low water.

“It’ll sterilize a stream for a long distance,” Neubecker said. A small stream like one of the branches of Thompson Creek would take a lifetime to recover, he continued.

Some of the gas leases in the Thompson Creek area have stipulations attached to them, to protect wildlife or other resources. Certain leases, including those along Middle Thompson Creek, have stipulations that no roads or well pads can be constructed within 350 feet of streams.

Neubecker said 350 feet is a healthy distance, but these protections aren’t as good as they seem.

“The biggest problem with those stipulations,” he said, “is they’re waivable.” If a natural gas production company complains to the federal Bureau of Land Management, the agency that regulates drilling on federal lands, that a stipulation is too onerous, BLM officials can decide not to hold the company to the restriction.

“So, there goes your protection,” Neubecker said. “Unless it’s mandatory, it’s meaningless.” Stipulations can also be meaningless if the BLM doesn’t enforce them, which is sometimes the case, he said.

As an example, Neubecker cited a spill from a waste pit on the edge of the Roan Plateau that happened last winter, that went unreported for four months. The spill polluted Garden Gulch, a tributary of Parachute Creek. The volatile chemicals in the water had evaporated long before any testing was done.

“If they had tested it at the time of the spill, they would have gotten very different results,” Neubecker said.

Neubecker said neither he nor Trout Unlimited is opposed to drilling for natural gas. But he said the industry should be more closely controlled, and there are places where drilling is not appropriate.