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Difficulty II-III+
Length Miles
Flow Range 500 - 2000 CFS
Flow Rate as of: 1 hour ago ~ 30.8 [CFS] ℹ️
Reach Info Last Updated 06/01/2020 9:05 pm

River Description

This river is far more continuous rapids than is typical of the Midwest! Do not take lightly the II-III rating! Paddlers should be strong, confident, intermediate paddlers, with an experienced group, before attempting this run at moderate to high levels. At such levels, most paddlers will be left with the impression of this river being essentially one long rapid, quite different from the usual pool/drop runs of the Midwest!

From the recommended put-in, a brief flatwater paddle brings you to some light rapids. Shortly you'll encounter a very low footbridge which will be a limbo at low-to-moderate levels, and will require portage at moderate-to-high levels. Soon thereafter the river assumes the character it will hold for much of it's length: essentially one, non-stop rapid. Trees in the current are not uncommon though usually can be paddled around. Be alert! As of April 2001 there was one beaver dam that could be 'snuck' by a paddle through the trees on the left.

While the 2.3 mile section above Hwy.28/141 generally does not exceed class II, it is recommended for it's warm-up value. If you are not completely comfortable with the style of boating you encounter on the upper reach, it may be advisable to abbreviate your trip at the Hwy.28/141 bridge. The pace decidedly picks up a notch downstream.

The river slows down a bit either side of the Hwy.28/141 bridge but soon resumes it's downhill race through the forest. The river is still generally class II, but you start encountering borderline III water the further downstream you proceed. As of April 2001 there was one large tree completely blocking the river. There is a brief respite in a swampy stretch that will warn you that you are soon approaching the most challenging section of the run. The river makes a turn to the left, tripping through waves and holes before turning sharply to the right at a rocky bend, where the action accelerates. This right-hand-bend often holds wood, though we've always been able to remove it to run the drop cleanly.

This drop signals the beginning of the steepest mile of the river. There is a wonderful rollercoaster ride of waves with a few lurking holes. Be on your toes and stay in your boat, as a swim here could take on epic proportions. This is a mile long class III rapid at medium to high flows. When the pace slackens off and the forest opens up, you will come to another low footbridge that signals the confluence with the Sturgeon.

There is a 3.4 mile flatwater egress paddle from here to the Plains Rd bridge on the Sturgeon. (This has been reflected in the length stated on the run name, but is not included in the "Length" or gradient figures in the description.)

Given the continuity of the whitewater and the ever-present danger of strainers on this small stream, the subjective difficulty is somewhat higher than the objective. Please exercise caution and discretion when paddling this reach, especially at higher flows.

Boaters looking for an additional challenge may consider finishing this trip by continuing downstream of the listed take-out to run Tibbets Falls on the Sturgeon (assuming the 'short take-out' is accessible.

Click here for Part 1 of an article from the AW Journal, way back in 1981!

Click here for Part 2 of the article.

The article describes the following: Michigan's, Upper Presque IsleLower Presque IsleMiddle BlackLower BlackUpper Silver,  Lower SilverFalls, and Rock; and Wisconsin's Lower BrunsweilerMontreal Canyon, and West Branch Montreal.

Rapid Descriptions


Class - N/A Mile - 0.33
Rapid Thumbnail Missing

A property owner has a very low footbridge which will be a limbo at low-to-moderate levels, and will require portage at moderate-to-high levels.

Hwy.41 / USGS site / Alternate put-in/take-out

Class - N/A Mile - 2.33
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USGS lists a sampling site at Hwy.41 with drainage area at this point of 40.3 square miles.

We generally recommend using the upper put-in (as listed on this reach). It gives boaters (especially those who may be less familiar with the run) a chance to 'warm up' and see what the run is like. If you have any difficulty or concern running the upper part of the run (down to this location), you should seriously consider taking out here. The run from here down steps things up a notch or two.

Main (largest) drop

Class - III+ Mile - 4.44
Rapid Thumbnail Missing

As the river sweeps to the left, it approaches the most significant rapids/sequence. At low-to-moderate flows, this may be boat-scoutable. At higher flows, (and even moderate flows, particularly for less experienced paddlers, or those not well-familiar with this run) scouting is highly recommended. A tight bend partway down is prone to containing wood. Action is very continuous for a good ways downstream. Anyone having problems anywhere on this stretch will be in for a long chase if they end up out of their boat.

Confluence with Sturgeon River

Class - N/A Mile - 5.88
Rapid Thumbnail Missing

This is the end (mouth) of the Rock River, and the end of the gradient on this run. From here, you normally have three miles of pretty much dead flat paddle out to the usual take-out. Directly across the Sturgeon River from the mouth of the Rock River, there is a house. It may be possible to (and one time we were there, we did encounter the property owner, who volunteered that we could) take out at that property to skip the long paddle-out. However, finding the right back roads to get to that property is not easy, and (if I recall) there is a gate (well back from the property) which will be closed anytime the property owner is not present. Thus, I would not count on using that access to eliminate the flat water paddle.


Gage Descriptions

* The reference gauge is for the Sturgeon at Sidnaw. Flows on the Rock should be approximately 20-25% of that flow.

Min/Max are uncertain, and correlation is not assured.

Disclaimer: Be aware that indication of a 'runnable' level by the gauge does not necessarily mean that the river is runnable. In winter, gauge readings may be 'ice affected'. Sections of the river may be impassable due to ice. Use discretion for winter and early spring runs.
This is especially true for this run, as the end of the run involves a three mile paddle-out on a very low gradient section of the Sturgeon, which is likely to remain ice-choked well after other rivers have flushed free of ice!

A boater's gauge consisting of three (faded, black) lines painted on center bridge pier at Hwy.28/141 bridge, corresponds to minimum, moderate, and mongo! Since that gauge is fading, more recent sets of marks have been made on the East bridge support. Ignore the larger (and slightly older) set of marks here, and read the five newer alternating blue and orange lines.
"Low" will be water levels below the bottom blue mark. (The river can probably be floated down until the whole bridge support is dry, but will be boney and generally quite 'tame'.)
"Moderate" will be between the lowest blue mark and the next orange mark.
"High" is anything above that orange mark. (I can't imagine seeing it at any levels approaching the upper three marks!)

Directions Description

We have no additional detail on this route. Use the map below to calculate how to arrive to the main town from your zipcode.

No Accident Reports




Thomas O'Keefe




Matt Muir


Revision #Revision DateAuthorComment
1215155 06/01/20 Thomas O'Keefe updated description
1196740 11/23/09 Rob Fix/remove broken links.
1192391 05/16/06 n/a
1195972 09/09/09 Rob Add abstract.