Following a Reclamation-NPS conference on Bridge's effect in November 1942, Olmsted reported to Drury, Jan 43, on the effects from two sites with a range of elevations: a lower Gneiss from 1772' up to 1835', and an upper from 1919' to 1970'. Based on Reclamation's own work, Debler had concluded lower Gneiss was better, and told the Commissioner that 1835-40' was the preferred height. Commissioner Page and Director Drury then talked it over, after which Page concluded, and told his Chief Engineer, that unless the advantage of a dam above 1772' was "very material", the invasion could be accomplished only with great difficulty. He doubted plans would contemplate a dam that put water into the Park, even though many thought invasion would not be detrimental. Contrarily, in February, the Chief Engineer recommended using the lower Gneiss site, to 1840', about three miles below Kanab Creek. Since NPS was not averse to development in the Monument, he suggested adding the affected Park to GCNM. The high-water debris would be below Havasu, and the reservoir would be full, mostly.
NPS also reported on possible camping sites and road access. Necessarily there would be extensive scarring, and more if aggregate were taken above the dam and dropped into place.
A January Reclamation report is in the archives with photos of the drifts showing what was done, up to as high as 1575'. The site to obtain the aggregate was on the south rim at the lower Gneiss site; easy to get at and almost pure limestone. Redwall not accessible.
To gather the materials necessary for the construction plan, the Kingman office was closed, concentrating office work in Denver . All field work was finished in February, with barges and tools released by March. The spillway specifications were down-sized because of the likelihood of upstream reservoirs. Calculations were being carried out to look for the best economic height. Sep 43, Debler told Olmsted that if the maximum elevation is below 1843', there will be an economic loss.
LADWP asked, with high urgency, for data, and received it. Debler used LA interest to press for a commitment by Interior to ask Congress to change the Park boundaries, making economics the foremost value. Geologist's report showed all sites excellent; upper Gneiss the best.
Oct 43, McKee made his report, but it is far more visionary than just the geology, the type of report that should have been made before making a Park. He visited Diamond Creek, below Toroweap, the Havasu mouth, and took a boat trip down from there to Bridge. He noted that the youngest strata at river level, after Marble's introduction, were around Havasu. He was impressed by the vast volcanics and the widened stretch along the Hurricane fault. He corroborated the fact that the Canyon was deepest here. The Cambrian record is remarkable for its completeness, and cannot be duplicated, although the greatest loss would be the lavas and ancient sediments. He dismissed the archeology and biology as not unique, and could be recorded before drowning. (Pooh! these geologists.) The Havasu area had striking scenery, but not great geology. He wrote that he was worried more about indirect effects and thought that sediment would mess up any development. He made the mistake of wanting to start the Grand Canyon where it widens at Nankoweap, as if a digestive tract did not include the mouth and esophagus. Called the Canyon a physiographic whole, even though there are differences. (I call it a topographic, geographic, geologic, educational, scientific, environmental, cultural, and ethical entity. That's how the 1975 GCNP Act defined it, and how could Congress be wrong?)
McKee's fine conclusion : It is not possible to say one part is inferior or superior; each is different, great, and part of the entirety. Remove one part and you lower the value of it all, exposing it to commercialization, exploitation, and misuse by private interests. He preferred that the Canyon be administered as an entity by NPS. Encroachments have been made, but kept to minimum, the vast remainder can be kept in the best interests of conservation. We should not dismember the developed parts.
Upon receipt, Director Drury sought more advice as to whether to try to keep encroachment below Havasu.
Although 1940 had been a scarily dry year in central Arizona, it seems not to have been until mid-1943 before Reclamation came seriously to study the question of how to move Colorado River water to the Phoenix area. The start of full war certainly could have been disruptive to planning, as well as Arizona's lingering noise and efforts going after the river on its own. An Oct 43 memo presented five routes, the Canyon instrumental in four. To the east, the idea of a diversion above Lee's Ferry to the Verde was re-worked with the dam in Marble Gorge. There were three tunnel routes from an 1840' Bridge site. (See the summary map in my 6/19/10 entry.) Unlike the fifth diversion--from behind Parker--, the Grand Canyon diversions would require subtraction of power lost. In any case, figuring construction at 3% interest, repaid over 50 years, none of the routes showed benefits (for irrigation) exceeding costs. This memo was re-worked in November and December, with Debler saying the Parker diversion could be built faster and had the best benefit-cost ratio. However, in contrast to the previous arguments about there not being enough market for the power, he now pointed out that the highline diversion from Bridge would save 3 billion kwh; which was a plus since regional energy resources were rapidly being exhausted. Still, no ratio of benefits to costs was greater than 1:1.
Dec 43, Larson wrote his report on the economic height of Bridge as a power producer only. The complications of the task are indicated by what he had to assume: What average stream flow figures to use based on the past, while projecting future upstream depletions? What dams upstream would exist to regulate stream flow? (He assumed a dam near Dark Canyon, above Glen Canyon.) He assumed a San Juan dam to catch silt. How much "live storage" behind Bridge to operate for economic optimum? How would the power operation be most productive? How much to allow for silt storage? He then looked at three heights--1840, 1870, 1885-- and figured construction, and then annual, costs for each. From these results he drew curves, looking for the largest margin of annual revenue over costs:
Debler approved his recommendation of 1877' with a dam of 750 mw capacity, and sent it to DC. Included was their conclusion that it would be best to modify the Park boundary to allow a height of 2000' (i.e., up to mile 131, three miles upstream from Tapeats) to accommodate 100' and 11 miles of backwater effects. A higher dam would be acceptable, since its power would still be more economic than other power in the area.
That same month, there was a geologist's office report on a "Marble to Havasu" tunnel, to get power "without interfering" with the Park. The dam would be in Marble Gorge at mile 36.5 with a 53-mile tunnel and a power house just downstream from Havasu mouth. No reason that it cannot be built at a reasonable unit cost, though we have yet to do field work. A Marble-Kanab-Bridge project would produce 11 billion kwh. Impressed by this daring idea, Debler immediately took a look, telling DC that he wanted to change the diversion options to include a 42-mile tunnel to Kanab. In a couple of days, his staff produced estimates for tunnels carrying 12-15,000 second-feet, leaving only a permanent flow of 1000 cfs for the Park. Perhaps it was a disappointment to learn that the results of the benefits vs. costs calculations did not significantly change, with Parker showing best at 1.01:1.
Continuing on, in Feb-Mar 44, drawings and estimates were put together for an 1877' Bridge power-dam. and a 2 million af diversion, although benefits still did not top costs. Not only did the Kanab tunnel not help much, there might be public disapproval, so perhaps it should be considered in the future. The Phoenix office engineer argued against looking further at the Marble-Verde route: unprecedented tunnel problems, long construction time. He did not like the amount of power required for the Parker route, either, so wanted to concentrate on the Bridge dam + tunnel-canal diversion. Arizona officials did prefer the Parker route, wanting the water as soon as possible. Debler disputed their calculations. At the regional level, Reclamation was also pushing the tunnel idea, worried about the Parker route's power needs. Its figure for building the tunnel from Bridge was 6 years, 8 months, 22 days. Since all this had been hurried work with meagre data, in June a new work plan was to be prepared on three routes, to deal with these considerations: Tunnels, a major question mark. There should be field geology with mine shafts. Factor in a Kanab power project. Work on getting NPS committed on all aspects of Park impacts, especially Bridge height and Kanab stream flow amount.
Reclamation notified NPS of the desired height in Jul 44, and also mentioned it was considering a Kanab tunnel diversion around the Park, to leave that 1000 sec-ft in the riverbed, adequate, it said, to preserve beauty and recreation values.
Jul 1944, there were U.S. hearings by Senator McFarland in Arizona to highlight the need for water and how to get it there. Debler presented figures, using the title "The Central Arizona Project" (CAP), assuming Canyon dams would be built whatever the decision about diversion. He started by emphasizing the uncertainties about water allocation which led him to assume a diversion of two million a-f to compare three plans:
1. Marble Gorge. high dam at mile 36.5, 139-mile tunnel to the Verde, dams along the Verde.
2. Bridge Canyon. high dam, 72-mile tunnel, two canals to the Phoenix area, with storage reservoirs.
3. Parker Pump. pumping plant to lift water 1040', canals and reservoirs as in Bridge plan.
The benefits and costs were still very close; the Bridge plan ratio was third. Parker could be built more quickly, but required pumping power, and would have the lowest surplus income. He emphasized how the comparisons could change with detailed investigations, which would go ahead under a state-federal cooperation contract.
Again, Arizona officials preferred the lower-cost, sooner-built-- three years as against 6-7 years-- Parker route. The engineers wanted to study all three, anyway, even when reminded that tunnels would have the cost of forgone power downstream. In November, the tunnel experts said they were reluctant to make cost estimates since they would not be trustworthy or fair. At this time, the Marble route seems to have been dropped due to tunnel and power considerations; a lower Marble could allow a high dam in Glen Canyon. Diversion was still being studied from Bridge to the Big Sandy River.
Mid-year, there had still been some secrecy about Bridge's height, Reclamation telling Senator Hayden it was a post-war project. Urgency to complete full Basin reports slowed down work on Bridge, but in September, Reclamation confirmed to the NPS Director that 1877' was the desirable height. A Park supporter asked about Glen and Bridge dams, and was told there would be none in Glen because of possibility of Marble.
LA asked Reclamation for study results, Reclamation replied by asking for LA's needs. It did not want to release power data because the height was still not settled, but would send data as long as it was not detrimental to federal interests. There was a meeting in November about water flow and possible silt retention dams. Reclamation was wary of letting out copies of its photos unless LA would treat them in confidence. LADWP's files show its continuing interest, 1943 on, in obtaining an "appreciable" part of Bridge's output, half the capacity is one figure.
In November, Reclamation was looking at Little Colorado and San Juan dams to hold silt.
As 1945 opened, Arizona's governor and other officials were "very much disturbed" at the slow pace of Reclamation studies. Also, Arizona congressman Murdock inquired about impact on Park and cutting out a piece, Reclamation answered it had more work to do, although a desirable height was 1866', with a 94-mile reservoir. Murdock kept up his interest, noting that if the Park was impacted, there might have to be legislation. More publicity about Reclamation's plans was showing up; a July technical journal article said Bridge would be the world's highest dam, and would have conduits to sluice silt through. An in-dam power plant was planned to avoid spray and heighten security. That section of the Colorado, it reported, was seldom visited.
Feb 45, Reclamation drew up a plan of work to look at a power tunnel from a dam in Marble, with an outlet in Kanab Creek. Apr 45, estimates were being prepared for various Kanab tunnel configurations.
Jun 45, An important element in the decision between diversion plans would be the effect on downstream power production. Reclamation worried about the controversy; there were such firmly held differences on routes and effects, and on how much water would be available for Arizona. It was important to have a decision soon on whether and how to account for downstream effects, complained the field to the Commissioner.
Sources: Bureau of Reclamation
National Park Service
LA Dep't Water & Power