The Role of Splash Dams in Northern Idaho

Marble Creek Splash Dam Project

Beyond the highways that wind through the valleys of northern Idaho, further than the reach of dirt roads that twist and turn along the steep mountainsides of the St. Joe River country, past even the foot paths that lead deep into the interior of the forest, flow the cool, clear waters of Marble Creek. Once the center of a fast paced, physical and dangerous industry, the stream has long since returned to its relatively peaceful existence.

If you were to have a birds-eye view of Marble Creek as it winds through narrow rock canyons, you would notice several sites where jumbled piles of weathered logs appear to have tumbled from the streambank into the waterway. A closer look from another angle or at low flow reveals a certain amount of order or arrangement to the logs. What is the significance of these structures, and why is there a renewed interest in them?

Marble Splash Dam


Figure 1. Looking upstream at a log structure during low flow on Marble Creek.

Remnants of Idaho’s History

The structures found here and elsewhere on Marble Creek are the remains of splash dams, crucial to the early logging industry in northern Idaho. Early settlers to Idaho were drawn by its beauty and the bounty offered from river valleys up through steep tree-covered mountains to the rocky peaks that rise above the tree line. Forests as far as the eye could see were used to shelter the waves of settlers coming to the region, providing timber with which to build their homes, barns, and fences. The wood filled the stoves on which they cooked their meals and heated their homes during the long, harsh winters, a luxury greatly appreciated by settlers who had recently crossed the tree-less plains of the mid-west.

A network of streams and rivers provided clean, constant water for drinking, crop irrigation and household washing and cleaning. An abundance of fish and game provided food for the settlers.
Along with mining, logging soon became the backbone of northern Idaho’s economy. By the late-1800s, logging companies from the eastern states had discovered the stands of huge white pines. Their challenge was in getting the trees to the mills, since the rugged terrain limited access by road or rail. A variety of systems were developed to make removal of the timber more efficient. Early logging in northern Idaho, as in much of the west, largely depended on rivers and streams. The development of log chutes and flumes greatly increased the efficiency of timber removal. Logs were skidded by horse or steam donkey (a steam-powered winch) to the log chutes (which relied primarily upon gravity) and flumes (which combined the use of gravity and water) to speed the logs on their way to the stream or river below.

Logs in Marble Creek were delivered into the St. Joe River, and eventually floated downstream to the mills. This method initially relied upon spring floods, when the water was high enough to move the logs. The drawback to that was that the logs were rocketed at high speed through the raging spring waters, slamming into the sides of narrow canyon walls and boulders in the stream bed. Many logs arrived downstream splintered or broken, sometimes too damaged to use.

A simple system of dams and gates was devised that made it possible to back up the flow of the stream into a pond and then float the logs downstream to the St. Joe River even during the summer and fall low water period.

A splash dam was a temporary wooden dam used to raise the water level in streams so that logs could be floated downstream to the sawmills. When the water was released, logs that had been dumped into the pond behind the dam, together with others collected along the watercourse below the dam, were quickly flushed downstream.
By impounding water and allowing it to be released on the log drive's schedule, these dams allowed many more logs to be brought to market than the natural flow of the creek allowed. Water releases from multiple splash dams on tributaries were also often combined to maximize the number of logs floated throughout a given watershed.

Most splash dams were temporary - when the pool was full of both water and timber, the dams were later dynamited, sending a torrent of water – and tons of logs – crashing downstream, where they joined those in the river and were floated to mills. Others, such as those on Marble Creek, were used for years to send logs to the river, and were abandoned after timber in the vicinity had been removed.

Once a site was chosen for the more complex splash dams the area was dug out so that thick timber could line the bottom of the dam. Logs were set parallel to the river and about thirty feet apart, then crossed with more logs sloped at an angle to relieve the pressure on the dam. Two high walls were built with a gate edged in rubber set solidly between them. A big wheel with a spool on the top controlled the gate; two men wound up the gear to open the gate. Gates remained closed until the water built up into pools behind the dam.

Logs were sent down the hills in wooden chutes or flumes that fed into the pools. Then the dams were opened in order, and the logs splashed into Marble Creek. A telephone connection told each pair of operators when to release the water and logs while big booms on the back side of the dam guided logs into the sluice gate. One by one the splash dams on Marble Creek were opened, pushing the logs into the St. Joe River. As the water and logs rushed through the gate, men worked behind the dam with peaveys (spiked poles with a hook-like device) to break up log jams.

Several dams were built on Marble Creek and its tributaries, and over the years were used to send hundreds of millions of board feet of timber downstream to the St. Joe River. By carefully timing the release of water from these dams, the level of Marble Creek was raised so logs could float down it without hanging up on rocks during low water months. Using splash dams allowed the timber to move under more control and ride higher in the water, avoiding much of the rock.

Splash dams were used in the North and Little North Forks of the Coeur d’ Alene River and tributaries to the St. Joe River; in addition to Marble Creek, those tributaries included Bussel, Eagle, Hobo, Homestead and Cornwall Creeks.

The Upper and Lower Dams

Now, almost a century later, most remnants of early logging have been washed away, worn down or overgrown by nature. However, some of those remnants are still having an impact. Of particular concern are two specific structures, located 35 miles from St. Maries, Idaho, and more than six miles from the nearest road. The structures (identified as the upper and lower splash dams) were built in 1915 and abandoned after 1931. Both are inhibiting fish passage for bull trout and other species that call Marble Creek and the St. Joe River home.

Archaeological investigations have occurred at both dams. The upper dam is a “rollover” or free flow dam of rock-filled structure, approximately 60 feet across (bank to bank), 12 feet high, and 35 feet thick. Logs 12 to 14-inches in diameter and about 12 feet long were split and nailed down as decking. There are no spillways or lift gates associated with this structure; water flowed over the top of the dam, creating a pool in back of the dam that was used as a landing and storage area for logs.

About half a mile downstream, the lower dam is similar to the upper dam, but also had two spillways, a lift gate, and two buffer dams. The spillways were formed by three rock-filled buttresses running through the dam, which was about 70 feet thick and 150 feet wide at the time it was constructed.

Both dams have been substantially damaged by natural elements, with many of the features (decking, footings, etc.) eroded, out of place, or missing.


Marble Splash Dam

Figure 2. The Lower Splash Dam, looking upstream from the right bank.


Marble Splash Dam

 Figure 3. The Lower Splash Dam, looking downstream.


Marble Splash Dam

Figure 4. The Upper Splash Dam, looking upstream from the left bank.


Marble Splash Dam

Figure 5. The Upper Splash Dam, looking downstream.


An Obstacle to Fish Passage

Upstream fish passage past four splash dams on Marble Creek was assessed in 2007 by Idaho Fish and Game. They found that two of the four dams (the upper and lower dams discussed here) were likely fish passage barriers while the other two were not.

The lower dam has deteriorated and considerable water flow occurs around and through the east side of the splash dam, but there is a drop of about 9 feet, which biologists considered to be probably more than bull trout can handle. The upper dam has not deteriorated as much as the lower dam, and is largely intact, completely blocking all upstream fish passage.
The Forest Service estimates the two splash dams will remain barriers to fish passage for decades.

A Proposed Solution

The U.S. Forest Service’s St. Joe Ranger District is partnering with the U.S. Fish and Wildlife Service, Idaho Department of Environmental Quality, Idaho Department of Fish and Game, and Avista Corporation to complete the proposed Marble Creek Splash Dam Passage Project.

The purpose of the Marble Creek Splash Dams Project focuses on improving passage for native westslope cutthroat trout and bull trout to allow them to re-colonize the high quality tributary habitat in upper Marble Creek that is blocked by the two splash dams.

Upstream passage on Marble Creek has been identified as critical to the re-colonization of bull trout in the upper reaches and tributaries where high-quality bull trout habitat exists. Bull trout are listed as threatened under the Endangered Species Act, and the Marble Creek drainage has recently been designated as critical habitat for bull trout.

These barriers prevent movement of bull trout and westslope cutthroat trout into several streams, most notably Delaney Creek, Freezeout Creek, Duplex Creek, and upper Marble Creek. This project is expected to help address recovery goals for bull trout in the Coeur d’Alene Lake basin.

Additionally, Lower Marble Creek is listed by the state of Idaho as temperature impaired by not meeting the Idaho water temperature criteria to protect cold water aquatic life. This project is expected to help address temperature conditions in Marble Creek by narrowing the stream channel at the project sites.

Constructed of log and rock, explosives are an ideal means of breaching the dams. Explosives would create a controlled and directional blast of just enough energy to breach about one-third (15 to 25 feet) of the width of each dam, leaving the remaining portion of each dam intact. The breach would occur along the most accessible side where the channel is the deepest and would provide the best possible fish passage.


Marble Creek Splash Dam Vicinity Map

Figure 6. Marble Creek Splash Dam Project vicinity map.


Preserving History 

The project design also recognizes the historical importance of the two splash dams. Both are eligible to the National Register of Historic Places; in addition, the upper dam is recognized as a Heritage Priority Asset that is managed by the Forest Service as a significant cultural resource.

Before undertaking any activities to modify the splash dams, ground-based LIDAR technology was used to preserve the structures in digital format so that they can be studied in detail. LIDAR operates by using a pulsed laser beam which is scanned from side to side over the survey area, measuring between 20,000 to 100,000 points per second to build an accurate, high resolution model of the ground. LIDAR can provide archaeologists with the ability to create high-resolution digital elevation models of archaeological sites (such as splash dams) that can reveal features that are otherwise hidden by vegetation, or in this case, water.

LIDAR Photos


For More Information

The Forest Service has completed an environmental analysis of the proposal to improve fish passage in Marble Creek. To learn more about the Marble Creek Splash Dams Project, please visit the webpage for the Idaho Panhandle National Forests:



  • Crowell, Sandra A. and David O. Asleson. Up the Swiftwater: A pictorial history of the colorful upper St. Joe River country. Museum of North Idaho. 1980, 1995.
  • DuPont, Joe, Jacob Hughes and Ned Horner, February 2011. Marble Creek Bull Trout Passage Assessment. In: 2007 Panhandle Region Fisheries Management Report; Rivers and Streams Investigations. pp. 154-160.
  • Russell, Bert. 1964. Calked Boots. Lacon Publishers, Harrison, Idaho.
  • Scott, Orland A. 1967. Pioneer Days on the Shadowy St. Joe. Caxton Printers, Caldwell, Idaho.
  • Sims, Cort. 1998. Flumes and Fluming in Northern Idaho. Idaho Panhandle National Forests, Coeur d’Alene, Idaho.
  • Sims, Cort. 1983. The Log Chutes of North Idaho. Idaho Panhandle National Forests, Coeur d’Alene, Idaho.

Many other wonderful books have been written about the history of logging in the St. Joe River country and throughout northern Idaho. Visit your local library to learn more.