BOISE - As a recreational suction dredge miner, Michael Emerson has encountered numerous obstacles in his small-time bid to hit big-time pay dirt: Angry property owners trying to boot him off an impromptu claim in the Owyhee Mountains, a 4 1/2 day stranding deep in the forest near Grangeville, even near-drowning last summer in the Salmon River.

Now, the 51-year-old Kuna resident has a new foe: The Boise-based Idaho Conservation League, which wants the Environmental Protection Agency to enforce long-neglected federal pollution laws that would, if they were followed, shut down recreational river mining in Idaho, at least for this summer.

"Oh, yeah. They (environmentalists) shut it down in California," Emerson says, adding that opponents have been "screaming up and down" in Oregon, too.

The Idaho Conservation League is asking the EPA to enforce provisions of the Clean Water Act that require hundreds of recreational suction dredge miners like Emerson to get pollution permits before they can stir up rivers with their floating, motorized vacuum cleaners with 5-inch hoses.

Not one permit has ever been issued for recreational mining. The EPA says it just doesn't have the resources, even if somebody actually applied.

That means everybody who lugs a suction dredge to Idaho's gold country rivers this summer will be breaking the law.

The fear, ICL activist Bradley Smith says, is that neither Idaho nor the federal government has any idea of the cumulative impacts of hundreds of small mining outfits on rivers from the Canadian border to Utah. The rivers are home to sensitive species like bull trout and spawning salmon and steelhead, as well as any of the gold that might be left since first luring prospector in the 1860s.

Last year, more than 400 people applied for the $10 state permit to use a recreational suction dredge on open Idaho rivers. The state permit, however, doesn't cover the federal Clean Water Act permit - that miners must get from the EPA.

With the price of gold near $1,500, Smith says interest will only rise - as could the impacts. Suction dredges create artificial gravel bars that make for attractive spawning areas for fish, but may be more susceptible to be washed out by high water rushing from the mountains the next spring, he said.

"Given the number of operations that are occurring, the price of gold, the impacts to water quality and native fisheries that are happening as a result, until there's a federal program in place to regulate that activity, it would be appropriate to step up the enforcement," Smith said.

Dave Tomten, an EPA geologist in Boise, said his agency is working on streamlined rules meant to reduce the administrative burden, but that the general permit won't be ready until at least next year.

After the Idaho Conservation League raised the issue, Tomten's agency sent warning letters to groups including the Idaho Gold Prospectors Association, telling them they set up their dredges on the Payette, the Clearwater and the Boise rivers at their own financial peril. Miners face fines of up to $37,500 if they're caught operating without a permit in such a way that hurts water quality.

Still, Tomten concedes the scenario of federal environmental agents swooping in on river dredges near historic mining towns like Idaho City, Rocky Bar or Placerville remains unlikely.

"It's been a low priority," Tomten said. "If we saw somebody that was tearing up a streambed, egregiously doing things harmful to the environment, we would intervene. But we don't see a lot of environmental harm happening."

Just the suggestion of intervention, however, has recreational miners jumpy.

They see what happened in California, where a court-ordered moratorium has been in place since 2009.

And in Oregon, litigation prompted environmental regulators to reissue their suction dredge mining permit last year, but dredging was never banned. New lawsuits by groups including the Hells Canyon Preservation Council are pending.

"Some of this is relatively benign, but if it's a fish-bearing stream, it's not benign, period," said Greg Dyson, Hells Canyon Preservation Council director.

Recreational miners in Idaho say they enjoy the outdoors and their activity's historic panache as much as diving into frigid mountain streams in thick wet suits to suction up the gravel in hopes that golden flakes will settle out over their sluice box riffles.

It's hard work, mostly for little pay.

"They struck nothing - absolutely nothing," said Christine Ballard, a Caldwell resident who bought a dredge with her husband in 2010 and mined near Rocky Bar in the Boise National Forest.

Environmental groups should focus on big mining operations, not mom-and-pop outfits more interested in recreation than riches, said Gary Scott, Idaho Gold Prospectors Association president.

Idaho already has adequate regulations, he said. For instance, Idaho's Wild & Scenic River system, the Frank Church River of No Return Wilderness Area and other rivers are already closed to mining. Scott also contends recreational miners actually can improve habitat, by loosening gravel for spawning.

"I retired and I wanted something to do," Scott said. "It's good to see a little color in the pan. I equate it to my going to Las Vegas or Jackpot or Reno. In each shovel full, there's a little anticipation."

The Idaho Conservation League sent out a press release warning miners to sit out the coming season - or face the possibility of a fine, however remote.

"It's not like anybody is going to be surprised about this," Smith said. "They've had fair warning."