Well I stayed up late and now there are 3 of us who made the trip...the eastern reporter, the family reunion group, and me (from my armchair listening to the gentle snoring of my gallant wife). Most enjoyed the walk up to La Gorce, the picture of the confluence with Bishop Canyon high and dry, the hike up Hidden Passage, and the frantic battle with the southerly downdraft (no rain mentioned) to secure the boat. Loved the oh-so-true-to-life commentary about so few clothing necessities needed for a week in paradise. All in all, well worth the wait, and who knows...you may be back in May to see another “facelift” with the lake at 3525, to discover the new wonders will be found then. Powell is the onion that you can just keep peeling, and it may actually be getting better as its secrets are exposed. Hear hear! to the most beautiful place on earth.
JFR on the lake Aug 6-12
- Thread starter JFRCalifornia
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JFRCalifornia
Keeper of San Juan Secrets
Thanks Dougie, I appreciate the nice feedback. Glad to take you along for the ride... And it would be good to be back next spring if the lake hits 3525 or so, but for now I'll settle for next week, when I actually will be back...Sunday through Wednesday...
Never thought of Lake Powell as an onion, but that probably means that if you sliced it up, it would be good on a burrito.
nzaugg
Keeper of San Juan Secrets
That was really nice! Your reports are always so lovely, I think you missed your calling as a travel book author. Regarding the gentleman from Denver with the ringtail encounter, I have had the same issue up north in Cedar canyon. Fortunately, I have never been one to allow the garbage to be kept in a spot where it could be rummaged through by the ringtail cats, though they did manage to get into the houseboat due to a door left open. They visited us 4 nights in a row, keeping me up for all of them. Not knowing what they were at the time, I was anxious about potential behaviors. The last night they were so kind to lick all the splatter off the grill though, which I didn't mind so much. Knowing what I know now, I think I would be less apprehensive about having them aboard, so long as there is no garbage for them to get into.
The frequent movement / reanchoring of the houseboat on your trip just exhausts me to think about though. I guess we don't have enough good hands for that much anchor work though and accessibility to cleats on our new houseboat is a real issue. I can't imagine moving the houseboat as frequently as you do, but then again, we drive for a long time the first day and don't explore the way you do. I would like to do more exploration, but I don't have as many takers in my crew.
The frequent movement / reanchoring of the houseboat on your trip just exhausts me to think about though. I guess we don't have enough good hands for that much anchor work though and accessibility to cleats on our new houseboat is a real issue. I can't imagine moving the houseboat as frequently as you do, but then again, we drive for a long time the first day and don't explore the way you do. I would like to do more exploration, but I don't have as many takers in my crew.
The pull of the Powell force on JFR is powerful. North launch again, or using the "resurrected" Wahweap ramp? (Stateline won't be done)
Looks mostly like good weather and some of that fall glassy water too!
Will look forward to another great trip report at 3547 (6 feet lower than last trip).
Here is the weather discussion from Flagstaff, SLC, and Grand Junction to triangulate on some wind potential for Monday/Tuesday. Looks innocuous at this point.
Flagstaff: For this weekend through early next week, the high pressure ridge
flattens over the southwestern U.S. while a more zonal flow
develops to our north. The position of this high will limit any
intrusions of monsoonal moisture, so dry and warm weather
will continue. Expect temperatures to run at least 5 to 7 degrees
above normal. There`s a slight possibility of a sharper trough moving
through the western states Mon/Tues which would result in
breezier conditions and slightly cooler temperatures, but we do not have
enough confidence yet to lean the forecast in that direction.
Salt Lake City: LONG TERM Ensemble guidance is in good
agreement in placing an elongated ridge over the area for calm and
seasonal temperatures Sunday. There are differences in how
an approaching trough will move east that will determine precip
and wind chances in the north for Monday. The south will stay dry.
Roughly 70% of the models do a quick brush-by and begin to expand the
high pressure ridge again by Monday night. That results in the trough not digging
southward, less synoptic lift, and largely dry conditions with less wind.
From Tuesday through Thursday there are differences in guidance, but
ones that won`t be a big factor in weather conditions. In any
case, tranquil conditions will prevail.
Grand Junction: Beyond Saturday, flow remains relatively zonal overhead as ridging
is suppressed to the south and a series of shortwaves traverse the
northern regions above I-70. This will maintain relatively dry conditions over
eastern Utah and western Colorado, with seasonably normal high/low
temperatures through the beginning of next week and light winds.
Looks mostly like good weather and some of that fall glassy water too!
Will look forward to another great trip report at 3547 (6 feet lower than last trip).
Here is the weather discussion from Flagstaff, SLC, and Grand Junction to triangulate on some wind potential for Monday/Tuesday. Looks innocuous at this point.
Flagstaff: For this weekend through early next week, the high pressure ridge
flattens over the southwestern U.S. while a more zonal flow
develops to our north. The position of this high will limit any
intrusions of monsoonal moisture, so dry and warm weather
will continue. Expect temperatures to run at least 5 to 7 degrees
above normal. There`s a slight possibility of a sharper trough moving
through the western states Mon/Tues which would result in
breezier conditions and slightly cooler temperatures, but we do not have
enough confidence yet to lean the forecast in that direction.
Salt Lake City: LONG TERM Ensemble guidance is in good
agreement in placing an elongated ridge over the area for calm and
seasonal temperatures Sunday. There are differences in how
an approaching trough will move east that will determine precip
and wind chances in the north for Monday. The south will stay dry.
Roughly 70% of the models do a quick brush-by and begin to expand the
high pressure ridge again by Monday night. That results in the trough not digging
southward, less synoptic lift, and largely dry conditions with less wind.
From Tuesday through Thursday there are differences in guidance, but
ones that won`t be a big factor in weather conditions. In any
case, tranquil conditions will prevail.
Grand Junction: Beyond Saturday, flow remains relatively zonal overhead as ridging
is suppressed to the south and a series of shortwaves traverse the
northern regions above I-70. This will maintain relatively dry conditions over
eastern Utah and western Colorado, with seasonably normal high/low
temperatures through the beginning of next week and light winds.
jayfromtexas
Well-Known Member
John,
Haha, yea the old "Sewage Lagoon". Would bet no one who has actually been there would mistake it for that. Last time I had the pleasure of boating Powell was in 2014. Was lovely as ever. Unfortunately family and other such travails have prevented me from making it back there recently but I do hope to go sometime in the near future.
Haha, yea the old "Sewage Lagoon". Would bet no one who has actually been there would mistake it for that. Last time I had the pleasure of boating Powell was in 2014. Was lovely as ever. Unfortunately family and other such travails have prevented me from making it back there recently but I do hope to go sometime in the near future.
JFRCalifornia
Keeper of San Juan Secrets
Thanks nzaugg! And I appreciate your insights on the ringtails...interesting! I've only seen them out there on the rocks, not in the boat.
As for whether I missed my calling as a travel writer, well that's a nice thought, but I don't see it that way. I'm already doing that, only just not getting paid for it. And as is always the case, when there's no money or editors involved, there's no pressure... much more fun that way...
JFRCalifornia
Keeper of San Juan Secrets
Thanks for the weather report! Yeah, it's looking good ahead... As for another trip report, well, it'll be shorter, that's for sure. Less lake volume + fewer days = fewer words
Probably.
jayfromtexas
Well-Known Member
As I read that laundry list of the GCI enviromeddler impact study, one thing stood out in my mind. What of all that darn silt? Say, if for by longest of odds the dam got removed, so then the silt would all flow down to Lake Mead and clog it up. Then what? Now the west is even worse off with only one reservoir and a whole bunch of mud flats clogging it.
JFRCalifornia
Keeper of San Juan Secrets
True enough, although I’d say that we’ve already seen that condition from 1935-63, when there was Lake Mead but no Lake Powell, and all sediment ended up in Mead… Makes me curious to know how sedimentation played out in Lake Mead in those pre-Powell days…
jayfromtexas
Well-Known Member
1969. Wow. I think I was an infant back then. That is a bit of a time ago. Presently, from Sentinel hub, it appears that the Colorado has created a "delta" channel in Mead clear down almost to South Cove boat ramp, it would be interesting to see just how far the delta would extend if all of Powell's sediment was washed downstream. Perhaps our resident expert Drewsxmi could shed some light on the issue.
No references yet, but I recall reading about problems with dust storms from the dried-out sediment deposited in the upper reaches of Lake Mead that got exposed during various droughts. From 1952 to 1958 was nowhere near full, and again from 1962 until about 1980. They built the penstocks at the Hoover dam to draw water from deep down so that the reservoir would not fill up with sediment. A quick Wikipedia read (far from authoritative) says that Lake Mead lost 10% of its storage capacity before the completion of Glen Canyon Dam. So 10% in 30 years > 300 years to completely full of sediment at Lake Mead (without Glen Canyon Dam).
There was a sedimentation survey done in 1986 at Lake Powell that measured 868,231 acre-feet of sedimentation in Lake Powell above the original contours, which comes out to 37,749 af/yr. At that rate by 2021 there should be about 2,189,452 acre-feet of sediment in Lake Powell currently. If that all flowed down to Lake Mead, it would make a noticeable difference in the 25,877,000 af capacity. The 37,749 af/yr rate would fill Lake Powell completely in 644 years.
The 1986 Lake Powell Survey (sedimentation rates) https://www.usbr.gov/tsc/techreferences/reservoir/1986 Lake Powell Survey.pdf has a chart showing the slope of the sediment delta on page 30. In 1986 the slope extended from about Dark Canyon (mile 163, about 3,680 elevation) to mile 140 and about 3,430 elevation. That's a drop of about 250 feet in 23 miles, or about 10 feet per mile as an easy approximation. If we figure the elevation of minimum power pool at 3,490, that's 210 feet below full pool, so the final sediment delta at full pool with power generation draining the silt from the face of the dam would be 21 miles from the dam, which I think is between Warm Creek and Gunsight Bays. That still leaves about 100 miles of main channel from where the sediment delta is now.
There are also effects of the topography and where the sediment load is coming from. White Canyon is blocked at the mouth by sediment from the main flow of the Colorado, and the larger bays (Bullfrog, Halls, Rock Creek, Last Chance, Warm Creek, Wahweap) would probably not fill with sediment, but would stay full with water. Also, the San Juan Arm is filling faster than the main Colorado channel, so there would be a sediment dam at the confluence of the San Juan Arm before the Colorado silt delta got there.
Also consider that sedimentation rates, precipitation, and land use are not constant. As we saw with the monsoons in the last few weeks, 50 years of sediment got washed out of Cathedral in the Desert in less than one month. Sediment loads from burn scars (Glenwood Canyon) will be much higher than thriving forests. I don't want to get into debates about cattle grazing and OHV use, but both of those will likely cause more sediment runoff from the affected lands. I'm really curious about what happened with the Dirty Devil River over the past couple of weeks.
nzaugg
Keeper of San Juan Secrets
One other issue to consider is carrying capacity and deposition in the natural river course. Part of the concern with Glen Canyon Dam is that the water coming out no longer has sediment so it prevents sediment deposition in the Grand Canyon, which restores beaches and allows nutrient and soil deposition along riparian zones. Because the sediment drops out in Lake Powell, it picks up additional sediment downstream, meaning total sediment movement with Lake Powell and Lake Mead is greater than it was just with Lake Mead.
I was pondering something else with sediment in the upper reaches. Suppose that Lake Powell was at or near full pool for many years. The sediment would be deposited in the lower part of Cataract Canyon and form a delta down towards the Hite Marina location. But the sediment starts dropping as the water slows, and would actually deposit above the full pool level (as can be seen on the San Juan).
UT-95 is not very high above the full pool level in that area, and does not have an easy way of raising the roadbed as it skirts the bottom of the cliffs by the temporary North Wash ramp. I could see UT-95 getting flooded by a silted in Colorado River after a few years with the reservoir at full pool. With enough money you can solve the issue, but I wonder if the UT-95 road designers even considered the possibility.
UT-95 is not very high above the full pool level in that area, and does not have an easy way of raising the roadbed as it skirts the bottom of the cliffs by the temporary North Wash ramp. I could see UT-95 getting flooded by a silted in Colorado River after a few years with the reservoir at full pool. With enough money you can solve the issue, but I wonder if the UT-95 road designers even considered the possibility.
nzaugg
Keeper of San Juan Secrets
I'm confused by your statement that UT-95 it isn't very high about full pool. I think the bridges are the low point on that roadway, and they are quite a ways off the river. Of course, they have the north wash area, as you mention, but I think it would be extremely difficult to envision even in a silted delta condition enough water that it would result in a constriction large enough to prevent the water from making its way through and flooding out UT-95. There is a lot of debris deposited at the high water mark, but even then, it was deposited at a level higher than the dam is now, since they were using plywood at the top of the dam, and is still a good 10-20 feet below the north wash roadway.
My guess though is that the road designers did not consider the possibility of a wash out of the road at a full-pool over multiple years condition since likelihood is small and overall impact to the travel plan for the state is minor.
My guess though is that the road designers did not consider the possibility of a wash out of the road at a full-pool over multiple years condition since likelihood is small and overall impact to the travel plan for the state is minor.
JFRCalifornia
Keeper of San Juan Secrets
Interesting thought. Well, the UT-95 road surface does come down to about 3720 or so as it sweeps north past the boat takeout toward the west side of the Dirty Devil. The graded roadbed might even be lower than that, but sure, it's close to full pool. I'm not aware of any flooding that happened in July 1983 when the lake briefly hit 3708, but I'm sure it was pretty close. As for the possibility of flooding caused by future sedimentation, well I guess I'd start with the idea that the top of the sediment would not be any higher than the highest water reached at full pool, which historically was 3708, but realistically about 3700. And let's one day say it all silts in to that level right there near the boat take out, the water at full pool in a post-sedimentation apocalypse is normally going to be confined to the areas downstream of that point, because silt will have taken its place, essentially a smaller volume of water in the lake, otherwise displaced by silt... but...
...at the same time, I could see a raging spring flood coming down the Colorado on a future raised silt bed just below the Dirty Devil, and hitting UT-95 crosswise, obliterating it like a pile of fancy hors d'oeuvres at the company Christmas party...
But I'm no hydrologist or any other kind of a -gist, so what do I know?
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We're totally off the subject of JFR's trip, but I remember the roadway being about 10 - 15 feet above the debris line from full pool. Along the San Juan River the sediment at Clay Hill Crossing was 71 feet by this study, and 78.5 feet at the mouth of Steer Gulch. (See https://animas.nmwrri.nmsu.edu/2019...nniny&Dott-FLC-AnimasRiverConf_2019-FINAL.pdf) That might not be enough to drown the bridges, but they would probably need to raise the road a bit. There would be some deposition above full pool level, just as there is sediment deposition above sea level in the Colorado River delta by Yuma.
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