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Lees Ferry BM 12

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I'm pretty sure that this




is GP0234 at the old Upper Lees Ferry site. It is not at the DS L/L and appears to be an outlined chiseled

square, instead of a triangle, around a tip of the native rock.



There is a somewhat cleared and smoothed cable pathway



running from a mound (DEADMAN) on river right down to a rock rip-rapped highwater landing



and lined up with an anchor point on river left. (Taken from kayak)








I would like to be able to say that I noticed all this on my first visit, but it was not until I went back the next

morning to use the 2oldfarts numbers and photos to find GP0233 that I happened to see this



just 41 feet from M 7. The NPS agrees that this is the old 'Upper Ferry' site



and the first clue should have been the interpretive sign on the way in.



If this one flies, the only one left in that immediate area is GP0236. It has some problems which I posted in a note.



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Nice job. What an interesting find. Pretty darn exciting.

We envy the added searching capability that you have with your kayak.

It's great that someone took the time to paint the “BM” on the rock so many years ago.


- I know you called it a square, but at least in the photos it looks like it has the possibility of being an eroded triangle.


- Any rough idea for when it might have been monumented? We performed a cursory search and found Southern California Edison Company momumentations from pre-1921 to 1973.


- The interpretive sign says there is a sunken steamboat – is that visible?


Wow – you are really racking up the Arizona finds.


Nice job.

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Thanks, TillaMurphs


The steamboat boiler and remnants of the hull are mostly submerged but visible along the shoreline.


I would think that BM 12 predates the 1921 M 7. I don't think that a somewhat fragile one would have been established that close to a permanent one. Of course, both are on a flash flood alluvial debris fan and could be taken out at any time.


Great coldwater fly fishery and free, no permit required, semi-primitive campsites in the 15 miles up to Glen Canyon Dam. kayakbird

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Is it possible you found BM 11 instead of BM 12?



Just a wild guess, but I suspect BM 11 and BM 12 were secondary marks to M 7 and set at the same time. Take a look at the 1921 USGS Annual Report:

"Arizona-Utah. — In cooperation with the Southern California Edison Co. the Geological Survey made special surveys and investigations in Arizona and Utah to ascertain the feasibility of storage and diversion of the waters of Colorado River. This was known as the Glen Canyon investigation. Surveys were carried from the mouth of Green River down Colorado River to Lees Ferry, Ariz., and in conjunction therewith surveys were carried from Bluff, Utah, down San Juan River to its mouth for the purpose of determining the capacity and extent of the reservoir, with a dam site located on Colorado River in the vicinity of Lees Ferry. In this work 485 square miles of topographic mapping (60 square miles in Arizona and 425 square miles in Utah) and 349 miles of river traverse were completed, for publication on the scale of 1: 31,680, with contour intervals of 5 and 20 feet. In connection with this investigation a dam-site survey covering 7 square miles was completed in the vicinity of Lees Ferry on the scale of 1:4.800. For the control of this project about 425 miles of precise levels were run by the United States Coast and Geodetic Survey between Green River, Utah, and Flagstaff, Ariz. About 130 miles of these levels, between Halls Crossing and Lees Ferry, follow Colorado River."

Nice scenery by the way. Looks a lot warmer than the 26 inches of snow that slammed us over the weekend.

~ Mitch ~

Edited by Difficult Run

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Looks fantastic. Hearing of the old ferry and steamboat really makes me want to go check that site out.


Like tillamurphs said, with 2+ feet of snow, nothing can be found out here. :/

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Difficult Run 'Is it possible you found BM 11 instead of BM 12?'


The second number on the rock is faint and could make it 11 (my paper with the description was with the camera I carry on the kayak so I didn't know that I was looking for a '12'). In that case the DATASHEET has a typo because this rock does fit the calls from my determination of the cable way.


Is there a description of BM 11?


M 7 and the rest of the 1921 string through here are Coast & Geodetic disks.


I like mysteries like this; but won't make it back there this spring for another look around. MEL

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It appears to us that you were on the wrong side of the river for it to be BM 12. When you look at at a map of the river, the river runs NE to SW putting the east side of the river on the opposite shoreline. Perhaps BM 11 is what you found and BM 12 is across the river at the deadman anchor on that side.


We will have to go and see what's what when we get some time off work. Can't check the other side since we don't have a watercraft.



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It appears to us that you were on the wrong side of the river for it to be BM 12. When you look at at a map of the river, the river runs NE to SW putting the east side of the river on the opposite shoreline. Perhaps BM 11 is what you found and BM 12 is across the river at the deadman anchor on that side.


We will have to go and see what's what when we get some time off work. Can't check the other side since we don't have a watercraft.




Here is a screen shot showing how the river runs and a red pushpin showing where M 7 / BM 12 are located.




Would a surveyor use the general term "east bank" or would he be more restrictive (the nearest 100 yards or so of the river) in its use. Generally speaking the 'east bank' is on the opposite side of the river from M 7 / BM 12. Restrictive speaking then the benchmarks are on the 'northeast bank' of the river.



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I have to agree with 2OF. Here's a closeup of the map showing an elevation of 3148 feet,

which differs from the given elevation by 1.6 feet. Historical image from http://www.TopoQuest.com



Coords are N36° 51.799 W111° 34.621 (DDMM.MMM)

Topozone has a better image than the one I posted, you just have to zoom in.


There's some interesting reading about Lee's Ferry on this website.

It's interesting to note that there were two ferries there, an upper and lower crossing, both occur where the river narrows.

This was because ferries used the increased current flow to propel them across the river using an angled rudder much like a sailboat uses the wind.

~ Mitch ~


(Edited to replace lost image)

Edited by Difficult Run

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A bit more information needed:


Is there a description somewhere for BM 11.


My DeLorme map program shows an estimated bearing of 251 from River Right to River Left for the ferry cable. I think that the surveyors would have rounded that to 'from east to west. Just upstream the thalweg is bearing 003 True.


I didn't whack a waypoint from the kayak, but I believe that I was looking close to due west when I took the picture of the ringbolt. No place for a cable way west of the ringbolt rock that would give you an 8 foot north measurement to the BM ?? Also didn't look like any place for a deadman on that step hillside.


A short level run in from LEES FERRY would verify elevations at M 7 and BM ??.


An aside - in the Pearce Ferry area there really are runs with three Bench Marks in a linear mile!



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We made it to Lee's Ferry today and it appears as though we have some bad news for you on BM12.


Here are a couple of shots showing the BM marking on the rock.


The long view highlighted by the arrow.



The close up shot.


Then we did a close inspection of the chiseled triangle. Here are 2 shots with some cornstarch to help show the mark. 1 shot with the GPSr (to make it easier for the next person to find it) and 1 without. When I was adding the cornstarch i had started following a crack, but noticed before completely filling it in. Hope the pictures are good enough to recognize the chiseled triangle.






Here is the shot of me standing at the required distance and direction from the BM 12?. I see no indication of this having been a dead-man. Also, it is directly in front of what was a building at one time, so I doubt that it would have been used as a dead-man, off to the side maybe, but probably not directly in front of it.




Here is a shot of the dead-man across the river. Note the red arrow point to the anchor point and the yellow arrow points to a rock with a chain draped over it. This rock appears to be in the correct position for BM12. It is approximately 7 feet north of the anchor point and about 30 west of the face (where the anchor point is) of the dead-man.



Close-up of rock and chain.



Without a watercraft we could not verify this is BM 12 but it does fit the description of the east bank and the distances from the dead-man and anchor point.


While we were there we did a check on GAGE RM1 and noticed This large boulder in the river and thought that it might be worth checking that area for the benchmark. It is at the right distance from the ferry and very distinctive so it strikes me as this would be something the surveyor would use as a tie for the benchmark.




Hope you enjoyed the scenery. We believe that BM 12 is on the opposite bank.



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Thanks for leading us to our first chiseled triangle, whether it is BM 11 or BM 12, it is our first!



These pictures are just for incentive to get you good folks here to enjoy the area. All were taken at Lee's Ferry area.


One of the boilers.



Name of the boiler company.



Sunken steamboat.



Rock formation, talk about a nose on that person. :laughing:



Another spire.



One more shot.


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Ohhhh, a nice balmy 55 degrees at our elevation. The pictures were of a Little bit higher elevations. 700-800 foot higher.


Then we went home the long way, up through the Kaibab National Forest at about 8000 foot elevation. Lots of snow there yet! :laughing:



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Great pictures of the Lees Ferry area! I'll try to slow down and get some posted for Pearce Ferry - the downstream end of the Grand Canyon - in a few days.


I did notice that large rock on river left when I paddled upstream, and climbed out of the kayak onto the smaller rocks - no RM.


Back to BM ?? I believe that the chain over the rock above the ringbolt on river left is well above the elevation of M 7.

GP0233* NAVD 88 - 960.279 (meters) 3150.52 (feet) POSTED

GP0234* NAVD 88 - 959.02 (+/-2cm) 3146.4 (feet) VERTCON

--------------------------------------------------4.12 lower


Still would like to see a description of BM 11. MEL

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Too much time searching the ozone the last few days, but I think that I finally found the definitive map

showing the numerous locations of the LEES FERRY RIVER GAGE since 1922.






BM 12 ???


Now to go find all the brass and the real Chiseled Triangle. MEL


THIS AFTERNOON AT LEES FERRY: Found USGS Gaging disk at the Lower Cableway and a Chiseled X at the Upper Cableway.






Stay tuned. kayakbird

Edited by kayakbird

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East bank, north bank...


If they were smart they would have used left and right, which never varies and can't be mis-interpreted...


Unless they get confused by 'Red Right Return'!!


I have high hopes that John and I will find GAGE RM 1 on river left on top of




these rocks that I spotted returning from two nights of kayak camping near P 7 1921.


But the question begs: if this is RM 1 and the non-published GP0235 was RM 2 (AKA N 7 1921), was/is there a recoverable DATASHEET for the GAGING STATION itself and RM 2?



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Scabbing GP0236 DESIGNATION - GAGE RM 1 onto here (partly because of the great 2OF'S photo spread above, but mostly because this entire complex ties together.


My logged note for GP0236:


Spent several more hours in this area on 6-7 Nov 2013 and this is how I see it: another 'clerical error' has this listed as a disk, but in truth the only 'disk' is the one on the river left anchor point for the upper cableway that was used 1922-28.


The call(585 FEET DOWNSTREAM FROM THE GAGING CABLE,) from that cableway take you right to the drill hole in the rock next to the grooves and bolts that obviously held a water measuring staff on the river left bank (black rectangle in below 'LEGEND' photo), and this is also the correct distance (60 FEET DOWNSTREAM FROM A LARGE ROCK IN THE RIVER,) from the only rock that fits the description. This location just happens to be - 0.2 MILE UPSTREAM ALONG COLORADO RIVER FROM THE OLD FERRY CROSSING AT LEES FERRY .


See screen shot photos from: Computation and Analysis of the Instantaneous-Discharge Record for the Colorado River at Lees Ferry, Arizona—May 8, 1921, through September 30, 2000 U.S. Geological Survey Professional Paper 1677 By David J. Topping, John C. Schmidt, and L.E. Vier


I did not get up to P 7 GP0238 this trip; but it appears that the DS is still one minute of Longitude in error.



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