Suction dredge mining has been in the news lately, with a federal judge in Idaho recently levying a record $150,000 fine against an out-of-state miner who refused to follow rules that protect the South Fork Clearwater River and the sensitive, threatened, and endangered fish that live there.

In response to that story, we’ve received a number of questions asking what dredge mining is, if it’s legal in Idaho, and why ICL cares about it.

First, What Is Suction Dredge Mining?

Suction dredge mining is a form of recreational gold mining that utilizes a high-powered floating vacuum. The miner dives to the bottom of the stream and uses a hose to suck up gravel and sediment. The dredged material (sediment, gravels, rock, and water) is then discharged through a sluice box on the back of the floating dredge, capturing the gold and spewing sediment and gravel back into the water. Dredge miners chew their way through the bed of the stream, using their dredge, along with crowbars, picks, hammers, and chisels to break up the bedrock in search of small flecks of gold – harming our water in the process. 

Suction dredge mining can wreak havoc on fish habitat and water quality in many ways.

  • Sediment discharged by the dredges can smother fish eggs.
  • Gravel deposited behind the dredges can create unstable spawning beds, which can be attractive to fish yet fail to provide the stable substrate that eggs need to survive.
  • Holes created by the dredging can persist and change river hydrology, leading to downstream erosion and creating dangerous wading conditions for boaters and anglers.
  • Mercury can be released into the water column, threatening public health, aquatic species, and downstream users.
  • Fisheries biologists, hydrologists, and others agree that suction dredge mining can be harmful to fish and threatens water quality. That’s why restrictions, limitations or statewide bans have been put in place in Idaho, Oregon, California, and other western states.
  • Dredges can harm streambanks and streamside vegetation as the equipment is hauled in and out of the water, or used to dredge beneath streambanks. Spilled fuel, oil, and other hazardous materials can also pollute the stream and riverbanks.
A suction dredge miner’s unpermitted operations on the Middle Fork Boise River.

Is Suction Dredge Mining Legal in Idaho?

Suction dredge mining is legal in Idaho, but because of its potential to harm streams and water quality, a patchwork of rules has been developed to control this activity, and not all rivers and streams are open to it. First, miners must limit their dredges to a 5” nozzle and 15 horsepower dredge. They also must receive permission from the Idaho Department of Water Resources (IDWR), Idaho Department of Environmental Quality (IDEQ), and in some cases the Idaho Department of Lands (IDL) and the U.S. Army Corps of Engineers (ACOE). If the stream is located on public land managed by the Bureau of Land Management (BLM) or Forest Service (FS), additional analyses and approvals are needed.

Not all the rules are consistent – some streams are listed as open by one agency, but closed by another. In order to legally dredge mine, all applicable permits and authorizations must be obtained.

An Agency by Agency Breakdown of the Rules

The Idaho Department of Water Resources issues Stream Channel Alteration permits to miners via a simplified process referred to as a “Letter Permit” at a cost of $10 (Idaho resident) or $30 (non-Idaho resident). The permit is contingent on also having a Clean Water Act permit from IDEQ, and agreeing to all other terms and conditions. Miners are supposed to note the location of their dredging, and are limited to rivers and streams where dredging is “open” during specific times of the year.

The Idaho Department of Environmental Quality issues free permits to suction dredge miners pursuant to the Idaho Pollution Discharge Elimination System (IPDES) under the terms of a Clean Water Act General Permit. The Idaho Suction Dredge General Permit, originally developed by the Environmental Protection Agency, requires permits be issued before dredge mining. The General Permit also restricts mining in federally designated areas (such as National Wildlife Refuges, Wilderness Areas, and Monuments), Tribal Reservations, National Wild & Scenic Rivers, Withdrawn Rivers, State Protected Rivers, in habitat for threatened or endangered species (including most of the Salmon and Clearwater Basins), or streams that are impaired by mercury, suspended solids, or sediment.

The Idaho Department of Lands (IDL) is responsible for permitting authority within state-defined Navigable Waters. On these specific waters, the state must provide public notice and show how they are protecting water quality, wildlife, navigation, fishing, and other values. The Idaho State Board of Land Commissioners, composed of the Governor, Secretary of State, Attorney General, Controller and Superintendent of Schools, also has the authority to withdraw rivers or streams from mining. Between 1981-1992, the Land Board withdrew 12 different rivers from mining, in addition to the five Wild and Scenic Rivers withdrawn by the Idaho Legislature in 1970. Further, IDL also has authority to issue 10-year Mineral Leases and 2-year Exploration Location permits for mining, and has issued several over the last few years. 

Finally, the Army Corps of Engineers is required to protect 10 separate Idaho lakes and rivers determined to be “navigable” under the definitions of the Rivers and Harbors Act of 1899. Under this law, federal permits are required for any activity below, within, or over a navigable water, including suction dredge mining.

Suction dredge mine. USDA Forest Service photo.

Special Rules for Special Places

In addition to the general rules and permits required by the agencies above, additional studies have been completed to allow for dredging in sensitive areas, including some habitat for threatened and endangered fisheries. Based on these site-specific analyses, limited dredging may be authorized in several streams in the Clearwater River Basin including the South Fork Clearwater River and in French, Orogrande, Lolo, and Moose Creeks. Before any permits are issued by IDWR, IDEQ, BLM, and/or FS in these areas, though, a fisheries biologist and mineral specialist must approve the site. Due to their popularity for dredging, other special rules are in place for Grimes, Elk, and Moores Creeks in the Idaho City area, and on McCoy Creek in southeastern Idaho near Palisades Reservoir.

So What’s the Problem?

Although these rules and regulations may appear to protect these sensitive rivers and streams, that’s not the case. There is a lack of consistent monitoring by the agencies that are supposed to be protecting these public resources. ICL has consistently seen miners dredging in areas that were closed, failing to obtain appropriate permits, or refusing to follow the terms and conditions of their permits. Some miners have dredged right along state highways, and right outside of Forest Service Ranger Stations with apparent impunity. 

Some agencies offer inconsistent guidance as well. For instance, the Salmon River is listed as “open” by the IDWR, but is “closed” under the DEQ rules, in order to protect critical habitat for threatened and endangered Chinook and sockeye salmon, steelhead, and bull trout. The same goes for the Middle and South Forks of the Boise River, which are listed as “open” by IDWR but “closed” by DEQ to protect critical habitat for bull trout. This leads to confusion among both dredge miners and other stakeholders. The bottom line is, if you’re a dredge miner, you need to know the rules – otherwise you could be facing stiff fines.

Another problem we’ve identified is that dredge fees paid to IDWR fail to cover the cost of administering the program. According to an analysis from 2018, the program takes in about $12,000 per year, and the cost of administering the South Fork Clearwater River permits alone costs ~$40,000/year. 

Proper monitoring and enforcement is key to ensure that dredge mining isn’t having unacceptable impacts on water quality. Agencies need to work together to ensure that permits are aligned, and fees should be updated to cover the cost of administration, monitoring, and enforcement. 

Dredge spoils and a deep hole are evident from unpermitted dredge mining in the South Fork Clearwater River.

What is ICL Doing About it?

For more than 40 years, ICL has recognized the threat recreational dredge mining poses to our streams. In our early years, we put pressure on IDWR and the Land Board to require permits, and to protect the Salmon, Upper Priest, Henry’s Fork, and other iconic rivers from harmful dredge mining. In the early 2000s, we advocated for EPA permitting to ensure compliance with the Clean Water Act. And when dredge miners refused to follow the rules, we held them accountable, resulting in the largest-ever Clean Water Act fine levied against an individual in Idaho history.

We’ll continue to monitor the permitting system and advocate for stronger protections with state and federal agencies. We’ve sent warnings to unpermitted miners, we continue to monitor streams and rivers across the state, and are prepared to hold other dredge miners accountable if they refuse to follow the rules.

Anglers, outfitters, boaters, irrigators, and others who use Idaho’s waters all work within rules and regulations to keep our rivers clean and healthy. Suction dredge miners should too.

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