Since there is water coming in one end and out the other, is there a measurable flow, however slow, throughout the former river canyon? If so, would the constriction of lower water levels inhabiting the narrower lower portions of the canyon serve to increase the speed of flow? Or if there isn’t a flow, could one be initiated by such a constriction?
Is there a current through Lake Powell?
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This is the time to pull out some big math, or just make up stuff as I go along... Let's postulate a flow of 30,000 cfs out of the dam, then pick the narrows between Warm Creek and Gunsight Bays. The lake is about 1,000' wide there, and about (very roughly) 300 feet deep. So the cross section is 300,000 square feet, so 30,000 cfs divided by 300,000 square feet gives 0.1 feet per second, or 0.068 mph. I doubt that you would be able to even measure a current that small.
The nominal "residence time" for water in Lake Powell is 7.2 years, so the water takes about 7 years to flow from one end of the lake to the other.
The current will be proportionally faster where the water is not as deep, notably up above The Horn. There has been some post-filling earth movement near the Rincon that left a shallower sill, and there might be a noticeable current there at minimum reserve pool and full spring flood flows.
It's nothing like the St. Lawrence River with currents in the high single digits in the navigation channel, though.
The nominal "residence time" for water in Lake Powell is 7.2 years, so the water takes about 7 years to flow from one end of the lake to the other.
The current will be proportionally faster where the water is not as deep, notably up above The Horn. There has been some post-filling earth movement near the Rincon that left a shallower sill, and there might be a noticeable current there at minimum reserve pool and full spring flood flows.
It's nothing like the St. Lawrence River with currents in the high single digits in the navigation channel, though.
Interesting. I suppose the 7.2 year “residence time” is a theoretical average vs an actual measurement of dye or whatever moving all the way through?
Anecdotally, I have seen debris moving perceptibly but very slowly southward as far down as the Bullfrog area in Spring runoff time. I imagine there may be an extensive area further South that has little or no movement, to make an average that is imperceptible.
Just idle curiosity, as it seems the lake regains more river canyon characteristics as levels drop.
The theoretical residence time is just the volume divided by the flow. The river channel in the Bullfrog area is only about 180 feet deep, so the flow will be faster. There could be a whole bunch of other hydrological things going on, like the warm inflow water staying at the surface because it is lighter (or flowing on the bottom, because the sediment load makes it heavier). I've read descriptions of the upper reaches of the San Juan Arm, with the river current disappearing for a couple miles, then resurfacing for a while. I'm sure that it is nowhere as simple as the flow divided by the cross sectional area.
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