Colorado River Stuff for CO,NM, AZ Zoners

copy and pasted from another forum:

"Never mind that those entitlements were based on an over-estimate of river flows in 1922, when the Colorado River Compact was established, rendering the “paper” water of the entitlements essentially a fiction, not to mention a source of continual conflict."

The common implication is that there was a deliberate overestimation of flows to create some sort of outcome that favored the lower basin. In fairness to those who drew up the Compact, a straight read of the data available at the time (inaccurate as it might have been) was that from 1906-1922, the average flow past Lees Ferry was 18.5 maf. That's why they felt comfortable assuming the annual flow would be 15 maf. Seems impossible to imagine today, but look at the record. Here's what it was:

1906 - 18.6 maf
1907 - 23.2
1908 - 12.5
1909 - 23.0
1910 - 14.5
1911 - 16.0
1912 - 21.5
1913 - 14.5
1914 - 20.7
1915 - 14.0
1916 - 21.0
1917 - 24.0
1918 - 15.5
1919 - 12.3
1920 - 22.0
1921 - 23.0
1922 - 18.2

Now those are gigantic numbers compared to today, or for that matter, even in the immediate decades ahead. It's as if they had a 1983 or 1984 level flow 10 times in 17 years. And it exceeded 15 maf in every year except four, with a flow no less than 12.3 maf. Could there have been error? Sure. Deliberate error? Hard to say. This much is certain: in the period 1920-40, the average flow at Lees Ferry was only about 14.9. In those two decades, it only topped 20 maf three times (1920, 1921 ansd 1929), with low years in 1931 (7.5 maf) and 1934 (5.5 maf). In fact, until 2002, 1934 was the worst year on record (1977 was close).

Here's the average annual flow at Lees Ferry (or after 1963, into Lake Powell) for 20-year periods in the 20th century:

1920-39 - 14.9 maf
1940-59 - 13.3
1960-79 - 10.8
1980-99 - 12.3

And in the 21st century until 2025? It's been about 8.4 maf.

So it's fair to say that things have changed, and are substantially less in the 21st century. Put it this way: the average annual flow since 2001 is less than EVERY year from 1906-30, and less than all but 15 years in the entire 20th century. (!!!)

Yes, there's been a change. Gotta address that reality.

The other nit-picky thing in the article is about this line:

"Such a scenario would compromise the dam’s legal downstream delivery requirements, or, to put it bluntly, its ability to deliver enough water to the 25 million people downstream who rely on it..."

People are always throwing around the "40 million people rely on the dam" or in the case of the lower basin "25 million". That does not paint an accurate picture. I think it's fair to say that those might be accurate numbers for the total population in the areas being served by river water, but the implication is that the river is the only (or even primary) source for those people. In most cases, it is not. That is especially true for the metro LA basin population, which has a pretty diversified water portfolio, and relatively little comes from the Colorado. That said, Arizona (and Phoenix in particular) is much more dependent on water from the Colorado...

the other forum is not too friendly towards the GCI.

It's mostly pro Lake Powell houseboaters and fishermen

Although the link you posted is on their too

some on the forum go out of their way to understand all sides of the issue

was lucky to have an uncle with a houseboat and small runabout on Lake Powell from 2002-2019

spent most time on the lake exploring the shoreline looking for fossils and dinosaur tracks

The Utah State biologist  for the lake started a forum mostly for fishermen but it grew into much more

I find it very informative. Even though I have no boats or friends with boats and don't plan on visiting the lake soon I still check it out right after I look at the zone daily

https://wayneswords.net/whats-new/posts/2106552/

click on new stuff on the main page

It's all good. We can come up with rational solutions like sucking the Great lakes dry, so almonds and suburbs can flourish in naturally dry regions of the country.  Plenty of folks believe that enough money thrown at a problem, buys a solution, but the amount of fresh water on the planet is a set amount.  Of the millions of chemical compounds we can create, chemists can't put two hydrogen atoms and one oxygen atom together to form anything more than a miniscule amount of water in a perfect laboratory setting.  Even a ship of fools requires enough water to sail on.

when I read Cadillac Desert for the first time in the late 80's the thought of the Compact expiring was so far in the future

futures here...

a little history this morning from wayneswords

The modern narrative is that Glen Canyon Dam arose as the result of an unholy deal. In the common telling of the tale, a proposed dam that would have flooded idyllic Echo Park in Dinosaur National Monument near the confluence of the Green and Yampa rivers was swapped for one in Glen Canyon because of a compromise between the Sierra Club and the Bureau of Reclamation in the early 1950s. As the story went, the Sierra Club—and its president David Brower—just didn’t know what they were giving away.

The story was not that simple. Stories like this never are.

The truth was that a dam at Glen Canyon had been considered for decades, and in one form or another was always part of a long-range plan to manage the resources of the Colorado River. As early as 1916, a USGS map of the Colorado River basin conceptually showed a dam at Lees Ferry, extending a reservoir beyond the Dirty Devil to near Mille Crag Bend, more or less covering the same footprint as modern Lake Powell. The map labelled it as the “Colorado-San Juan Reservoir Site.” Crucially, the same map showed another reservoir behind a dam near the confluence of the Green and the Grand, pushing upstream into both rivers, to Green River, Utah along the Green, and beyond Moab along the Grand, as the Colorado River above the confluence was known at that time. This two-reservoir plan was instrumental in how the USGS envisioned the location and design of a dam in Glen Canyon.





It took detailed survey work along the Colorado River over the next several years to flesh out that concept. By 1923, those surveys were completed, and that effort was described in the May 1924 issue of National Geographic. More importantly, the results of survey would soon be more fully documented in a landmark 1925 report by E.C. LaRue, the chief surveyor for the USGS.

Officially known as Water Supply Paper 556, or Water, Power and Flood Control of Colorado River Below Green River, Utah, but commonly called the LaRue Report after its author, this was the definitive survey of the canyons of the Colorado River and its tributaries, with a specific eye toward locating future potential dam sites. Forming the backbone of the report, these surveys were the first major systematic and scientific studies of those rivers since the days of John Wesley Powell a half century before. Largely conducted outside the eye of the public, they were the most important first steps to shaping the future of the West.

The resulting 300-page report was stunning in scope, and included detailed maps, analysis of historic flow data, survey results, and recommendations for dam sites and the water supply and hydroelectric power that could be realized. This report became the formative blueprint for all future actions undertaken by the Bureau of Reclamation in the coming decades, although modified considerably to address the interstate politics of water, especially the immediate flood control, irrigation and water supply needs of southern California.

In the end, LaRue’s report recommended 13 dams along the system that could store 42 million acre-feet of water. One of those was a dam at Glen Canyon. As described in the report, that dam was envisioned as much smaller than the one ultimately built decades later—impounding perhaps 8 maf of water, about a third of the capacity of the dam that would eventually be constructed. Full pool would be no higher than 3513. The reason for that was because the report also contemplated another dam in Cataract Canyon just above the high-water mark of a possible Glen Canyon reservoir, impounding water upstream from Dark Canyon at elevation 3528, flooding both the Green and Colorado all the way to Moab, Utah. The dam at the lower end of Glen Canyon had to be small enough not to interfere with this facility.

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The report also discussed the importance of not interfering with Rainbow Bridge, and that a reservoir limited to 3513 at full pool would not come close to encroaching on the National Monument or the bridge itself, an important legal consideration. (As a side note, the report concluded that it would take a reservoir with a capacity of 32 maf to interfere with the Bridge abutments.) At the same time, it recognized that a reservoir would greatly improve public access to Rainbow Bridge, and that one day when there was roadway access to such a reservoir, annual visitation to the Bridge by boat might be as much as 200,000.

And here was the report’s key pitch to building Glen Canyon Dam before any other dam in the system:
 

“The continuous power capacity of all power sites in the Grand Canyon and on the lower river would be more than doubled by storage at Glen Canyon, and in addition every hydraulic structure subsequently built on the river below Glen Canyon could be constructed at a greatly reduced cost; as it would not be necessary to take care of long-continued flows of flood water during construction, and the spillway and storage capacity required at such works could be reduced to a minimum. It is estimated that building the Glen Canyon dam first would result in a saving of millions of dollars on dams subsequently built on the river below this point.” ​

As an indicator of how serious the Glen Canyon Dam proposal was at the time, the USGS considered eight potential sites in Glen Canyon, from near Lees Ferry all the way up to near Lake Canyon. The report highlighted the pros and cons of each, and listed them in the order of recommendation, even showing a drawing of what a dam would look like at its preferred location, which was called “Glen Canyon Dam Site No. 1”, about 4 miles upstream of Lees Ferry. These were the eight sites, in the report’s order of preference:
 

1. Glen Canyon Dam Site No. 1. About 4 miles upstream of Lees Ferry, river elevation 3127.​

2. Glen Canyon Dam Site No. 2. About 9.5 miles upstream of Lees Ferry, river elevation 3129.​

3. Sentinel Rock Site No. 1. About 7 miles upstream of Wahweap Creek, elevation 3152.​

4. Sentinel Rock Site No. 2. About 2 miles upstream of Wahweap Creek, elevation 3147.​

5. Oak Creek Dam Site. About 0.25 miles downstream of Oak Creek, or 7 miles downstream of the San Juan River, elevation 3241.​

6. San Juan Dam Site. About 0.5 miles downstream of the San Juan River, elevation 3258.​

7. Escalante Dam Site. About 7 miles upstream of the Escalante River, just downstream of the Rincon, elevation 3280.​

8. Bedrock Dam site. About 1 mile below Lake Canyon, 6 miles downstream of Halls Crossing, elevation 3325.​

There are fascinating details in the LaRue Report about each site, and I’ll highlight a few of those here.

Sites 1 and 2. The two dam sites near Lees Ferry stood out from the others mostly because they were relatively accessible as construction sites, since it was possible to reach Lees Ferry by automobile, even then. (Consideration of a dam near Lees Ferry was likely one impetus for completing the Navajo Bridge over Marble Canyon in 1929.) But of the two sites, it was Site No. 1 that the report focused on, clearly the preferred location among all eight of them. LaRue had his eye on this one all the way back to 1915, and it formed the basis of what was shown on that previously mentioned 1916 map. It was reported to have favorable geology (confirmed by a geologist working at Southern California Edison), and additional construction materials could be excavated not far away at Lees Ferry or the Paria River. That was important, because it was determined that the sandstone at the site itself was not suitable for use in making the necessary concrete aggregate. Full pool at 3513 would result in a reservoir 386 feet deep, which would maximize power generation compared to sites farther upstream.

Here's a rendering of a dam at Site No.1, included in the 1925 report:


Sites 3 and 4. The two damsites between Wahweap and Warm Creek (one of which is not far from where Antelope Point Marina is today) had similar geological characteristics as the ones farther downstream, but were farther from the potential sources of aggregate at Lees Ferry, and even more inaccessible from a construction standpoint than ones farther downstream. Interestingly, the report noted that a railroad extended from the south might be possible to serve a construction basecamp on the nearby plateau where Page, Arizona stands today.

Sites 5 through 8. The remaining sites farther upstream were clearly less desirable and rejected with little further study. The Oak Creek site had favorable geology and the report even suggested taking advantage of Oak Creek (aka Secret Canyon) as part of a possible spillway system. But the site was prohibitively inaccessible to construct cost-effectively. It was a similar story at the San Juan damsite. Farther upstream, the report rejected the Escalante site out of hand, not even bothering to conduct detailed survey work, because of its poor geology for a dam (shale) and terrible accessibility. The final site near Lake Canyon had more promising geology, but still had the problem or poor construction access. In addition, it was so far upstream that its base elevation was over 200 feet higher than the sites near Lees Ferry. This limited its capacity because of the upper limit of 3513 to avoid interfering with a dam Cataract Canyon.

Interestingly, when the dam was finally authorized three decades later, it was built at a location not even considered in the LaRue report. More detailed survey work at the report’s preferred location near Lees Ferry revealed geologic flaws, and it was determined that the closest site to Lees Ferry suitable for a dam would be about 11 miles farther upstream of the originally preferred site. And that is where the dam stands today.