Colorado Parks and Wildlife is reiterating its desire to see regulators consider limiting oil and gas pads to one per square mile in critical big game habitat.

Gov. John Hickenlooper raised Parks and Wildlife's concern last year in a letter to the Bureau of Land Management about its December 2018 lease sale, and the agency ultimately deferred offering most of the acreage in the sale largely because of a number of wildlife and other issues raised by the governor. In a letter to the BLM on its upcoming March lease sale, which is proposed to include a number of northwest Colorado parcels, Parks and Wildlife Northwest Regional Manager JT Romatzke again noted the state's hope of seeing the BLM limit pads to one per square mile for parcels with the highest-priority big-game winter range habitats and migration corridors.

"Until an adequate mechanism is in place to provide these protections, CPW recommends deferral of these important habitats from this sale, and future lease sales," he wrote.

In Hickenlooper's July letter, he pointed to an order issued by Ryan Zinke, then the Interior Department secretary, to have Interior agencies work to protect and enhance big-game winter range and migration corridors.

Hickenlooper cited growing evidence that seasonal timing limits on oil and activities aren't adequate to protect crucial big-game corridors and winter habitat, and wrote that impacts to big game "are considered high or extreme when well-pad densities and associated roads exceed four pads/mile."

Dean Riggs, deputy manager for Parks and Wildlife Northwest Region, said that with big game, particularly deer, in starvation mode this time of year, "having places they can go where they can be basically left alone is the best-case scenario."

He noted that Parks and Wildlife only can recommend well-pad density limits, as it has no regulatory authority over land management agencies or oil and gas developers.

"Whether a land-use management agency takes those recommendations and does anything with them is totally up to them," he said.

Riggs said Parks and Wildlife also is in continuing discussions with Colorado Oil and Gas Conservation Commission staff when it comes to protections that might be considered for wildlife.

Said Kathleen Sgamma, president of the Western Energy Alliance, "Colorado is just starting to address density in critical big game habitat and migration corridors, so the state is asking BLM to do something it hasn't even figured out yet. That's putting the cart in front of the horse. Just tossing out a hard and fast standard without the required deliberation and stakeholder input is not the way to set good government policy.

"BLM should certainly consider Colorado's policy once it's gone through the deliberative process that addresses actual conditions on BLM lands, but until then, BLM should proceed forward with the leases."

Don Simpson, an adviser and former vice president for Ursa Resources, said that a rigid limit of a pad per square mile would affect energy development in Rio Blanco County, where it has begun drilling.

"We prefer some flexibility to locate pads, like the process currently in place," which involves working with Parks and Wildlife "on locations that are reasonable, sensible and limit impact to wildlife," Simpson said.

Eric Carlson, executive director of the West Slope Colorado Oil and Gas Association, said a pad per square mile would essentially mean one-mile setbacks between pads, twice the 2,500-foot drilling setback ballot proposal that Colorado voters defeated in November and would have applied to homes, waterways and other resources.

"That would be just untenable," Carlson said.

He said he's not aware of any studies addressing the issue, and he also has concerns about a hard and fast standard.

Riggs said the reality is that there will never be a strict limit of a pad per square mile to protect big game. He compared the situation to that for greater sage-grouse in the Piceance Basin, where a pad per square mile might be the goal but rolling terrain can help provide barriers that protect the bird and might allow for more development.

"We're always looking to try to work with industry, work with BLM … and determine what's the best plan of action, knowing that development's going to occur," he said.

He also noted that companies have come far over the last 15 years when it comes to deploying directional drilling. Whereas they once drilled one well per pad, they now often drill dozens from a single pad.

Several years ago, Encana drilled more than 50 wells from a single pad outside Parachute, enough to produce gas from a square mile.