Originally Posted by asleep.at.the.oars
Not really a definitive answer, but I really believe thinking outside the traditional environmental arguments would allow for Powell to be removed with a fairly minimal total economic impact.
Powell water allotment is minimal. They also provide water to Page and the coal plant but those are microscopic in the big scheme of things.
To be fair though water loss is significantly lower in drought years in the lake so part of the argument diminishes. Its also important to note that stretch of river lost 102,000 AF a year before the dam according to the GCI, which has a 12% decrease in the annual loss used most often. Much of the "loss" stated is actually is to seepage which isn't really "lost" at all but thought to be recharging the local aquifers. Lost to the compact but not the region. I also thought a large portion of that was lost in the first decade during filling (like 1/3 total water storage at full pool).
I am curious about the statement above...how would the figure be minimal? Even at 50% power generation (the most consistently quoted average) we are still talking solar generation in the range of 30 times the size of Ivanpah. BoR claims roughly 75% capacity but I can understand why some folks might consider that # suspect. Offsetting the hydro plant with coal would largely be unconscionable in the Grand Canyon region in my book and inconsistent with dam removal. The bypass option does offer just less than a decade of extra power generation but the concept of leaving that Dam in place is unappealing to say the least.
I also think the idea that the economic cost would be "minimal" ignores the ecological restoration costs. If the major rational for removal is environmental and ecological than restoration would be key. Sediment removal would likely take decades and require infrastructure itself. GCI claims 6-8 years for the main stem but I found no support for that estimate. Considering the side canyons were the main draw I think their sediment erosion would be a key metric of success. The lower stretches of Cataract, the San Juan or Diamond Down paint a real picture of how damaged these systems are after inundation and for much longer than anti-dam organizations claim.
Restoring aquatic systems would be a gargantuan undertaking that could take decades. They would have to poison the entire stretch including side canyons. Several of the sports fish would die naturally when the lake is decommissioned but many would survive. The channel catfish would be one and its a major predator of native juveniles.
I have never heard how agencies would revegetate such a massive landscape. Invasives tend to currently be more successful at reclamation of damaged ecosystems so this is a major threat. Not to mention all of the large trees in the main corridor and side canyons are dead. We are talking about 180 miles alone on the main stem of the river. From what I can tell about 1/2 the $325 million for the Elwha went to ecological restoration for 321 sq miles of shoreline. Revegetating and restoring 108,000 square miles of shoreline in a region with massive issues of invasive is a staggering effort that is anything but cheap. It seems counterproductive to drain the reservoir only to allow it to be inundated by aquatic and terrestrial invasive species.
I think we have the imagination and manpower to do a lot with Glen Canyon but "minimal economic impact" doesn't seem to be in the picture at all. The myth of Glen Canyon is largely perpetuated on bucolic scenes of sandy beaches and hikes like Cathedral in the Desert or Music Temple. Without considerable economic and human investment I easily foresee 180+ miles of a wholly desolate, ecologically dysfunctional and uninviting river corridor. Realistic outcomes normally sit somewhere between two points of such spectrums. But I have to wonder what is the point if it ends up closer to the current examples than the ideal?