Adequate river depths

Planning itinerary for trip home. What terms to google to find adequate river depths for specific rivers. The USGS gives that information, but that is meaningless unless one knows what the depth has to be for the section of the river one wants to paddle. In particular: Au Sable MI, south branch Chase Bridge to McMaster Bridge, main branch from Grayling to Wakely & McMaster Bridge; Mohican and forks OH at Loudonville, Sheyenne ND at Fort Ransom. Are there river maps available which give USGS gauge stations and acceptable depth levels for navigability downstream of those gauges? Failed to do that on trip north and found 2 dry rivers.

The gauges can be problematic
I have found that most USGS gauges are located in areas that allow for easy access to service the gauge and often do not reflect depth reliably. Areas where rivers widen out often drop to non-passable levels even if a gauge indicates acceptible depth in a back up or narrowed area of the river.

If I have plans to go to areas that I have never been to I have had good luck locating local paddle shops on google maps, or “get together” groups on facebook and asking them for river (or lake) information.

call a livery
there are a few in the Roscommon area, more in Grayling on the main Au Sable. they’ll have the best info on current river conditions and can shuttle you.

The Au Sable is spring-fed and generally canoeable throughout the summer. looking at this gauge on the South Branch,

the level has been consistently over 4 ft since Spring. it averages 2-4 feet most places, there are a couple shallow spots but you should be OK. you can paddle from further upstream, but putting in at Chase Bridge avoids the populated section.

Make phone calls

– Last Updated: Sep-02-12 2:24 PM EST –

All of Michigan's 83 counties were declared primary disaster areas
caused by drought and extreme heat.
-From The Detroit News - August 30, 2012

USGS gauges are basically useless to outsiders.
For those that live in the area they can "translate"
the reading much more accurately into reality.

Fishing Guides -
Old AuSable Fly Shop and Gates AuSable Lodge
(989) 348-3330 and (989) 348-8462

The USGS gauges have Median info
The best way is through experience but you can get an idea by studying the Medians.

I work by analogy. Besides info I get
from postings by other paddlers all around the country, I’ve paddled myself in about 41 of the lower 48 states.

So, if I have to guess the depth and negotiability of a “new” river, I try to compare it to rivers of similar size (cfs, watershed area) in the same area, or in similar geological areas. I especially note whether there are outfitters on the “new” river, and benefit from their knowledge. However, outfitters (for financial reasons) often consider their river to have “enough” water when I would not want to bother with it.

As an example, this August we went to Lake Superior Provincial Park in Ontario. I knew that some rivers, like the Sand River and the Agawa, are OK in wetter periods, but I knew from nearby US gauges that the eastern Lake Superior rivers were low. Then I noticed that Superior Adventures runs regular trips on the Michipicoten River, and old portage route for the Hudsons Bay Company. The river is dam controlled. I guessed that, even in a low water month, the river would have enough water for paddling. And I was right.

On the other hand, I researched the Indian River in the Michigan UP, said (in a guidebook) to have enough water even in summer. When we got there, a ranger lady told us that because of unusually low water, any who tried paddling were having to walk and drag long sections.

Remember—most paddlers are hopelessly optimistic about water levels. Structure your planning and research accordingly.

Gauge readings and depth
The first rule is to stop using the terms “gauge” or “gauge reading” in the same sentence as “depth”, because those words are not related to each other in any way. The gauge reading is ONLY related to the manner in which the first gauge at that particular location was constructed, when some guy nailed a big wooden “yard stick” to a bridge piling or abutment. That person positioned the “yard stick” at such an elevation that the bottom end would (hopefully) never be left high and dry, but the “zero” reading on the “yard stick” was not, and is not, the same as the bottom of the river. It’s below the surface by some arbitrary amount. Useful information includes changes in gauge readings over time, differences in the present gauge reading from long-term averages or from the readings at other known times, and correlation between specific gauge readings and rate of flow expected to occur when the water is at that elevation. The numbers themselves are meaningless without additional info.

With that out of the way, the other advice posted already will make more sense.

A.W. Flow Page
American Whitewater,On their website they have a River Data/Flow Page.

It has data on A LOT of Rivers in all states…C.F.S. and or feet,min. float dept/flow,put-in take-out,pics and data.

IFN U beez paddln in the southeast look at ,

As Guideboat Guy…
noted, the gauge readings of level in feet are not related to the depth at all. FORGET about getting any useful info from a given level in feet reading, period. Learn to use the OTHER piece of info on most gauges, the flow in cubic feet per second, and the table that shows the median flow for that date as well as the present flow.

If you happen to know that NORMALLY the stream in that section is floatable at this time of year, then by looking at the present flow and the median flow, you can estimate how close to normal the river is right now. The median is usually pretty close to what would be considered the normal flow.

You can also look back at some of the historical flows. For instance, if you’ve floated the river before and happen to know the date of the last time you floated it, you can find what the flow was on that date, and relate it to the present flow. Also, if you have not floated that stream, but have floated another stream in the same geographic region and know the date that you floated it, you can look IT up and see what the flow in cfs was that day, and relate IT to the present flow on the stream in question.

Most streams in a specific geographic region have about the same character. For instance, I know that most Ozark streams have about the same characteristics. After watching gauges for a long time and relating the flow in cfs to the experience I had floating those streams, I know that, in the Ozarks, just about any stream flowing more than 100 cfs will be fairly easily floatable, 75 cfs and you’ll be scraping bottom in some riffles, 50 cfs and you’ll be scraping bottom a lot, and anything under about 40 cfs and you’ll be walking the riffles a whole lot. I just finished a “paddle-drag” float on a small stream under the present drought conditions here in the Ozarks. I checked the gauge and it said the stream was flowing all of 15 cfs! So I knew it was going to be a paddle-drag trip and planned accordingly. I ended up floating less than 10% of the riffles in a 25 mile stretch of stream (over three days) cleanly, and should have walked at least 50% of them, but instead just used the paddle as a pole to push myself through many of them.

Gauge locations

– Last Updated: Sep-02-12 11:55 PM EST –

Gauges are typically located at bridges, and it has nothing to do with easy access, though that is an accidental advantage for those who work on them. They are located at bridges so that the cross-sectional area of the stream can be accurately defined for any given water elevation. Accurately knowing the cross-sectional area of the stream is necessary so that once typical current speeds associated with various water levels are known, flow rate can be calculated easily. Imagine trying to calculate flow rate at some typical location when the river is flooded. How would you measure the current speed and cross-sectional area back in the trees or out in a corn field behind the river bank? Conditions would be just too variable to measure well. How would you know cross-sectional area at normal river levels at ANY time following a flood which had scoured one or both banks, deposited sand bars, etc. It would be a LONG, tedious process establishing the new dimensions of the river at the gauge site in that case. However, at a bridge, the "banks" are usually pretty constant over time, and any changes in channel topography are easy to measure. Incidentally, taking current-speed readings at multiple depths and locations is usually pretty easy at a bridge site too, which is nice, but not the primary reason the gauge is placed there.

River flow
River flow in CFS (cubic feet per second)is the way we check conditions in our local rivers. All of our rivers are dam controlled so flows can change dramatically.

Locals who know the river know what paddling conditions the different flow rates offer.

Learning to interpret CFS
Two outfitters gave me two different assessments of the same stretch of a river. One said that the river was fine, they had just sent a group out and there was no problem; the other said that we would be scraping our kayaks in some areas and may have to pull the boats in certain parts. The CFS seems to be the best way to get at, at least a basis for evaluating what the outfitters say. Is there a good source that would explain how how cfs relates to navigability – one without equations?