Glen Canyon Restorative Flood into Grand Canyon

[chumley]

After a couple of successful tests in 2008 and 2011, the first of the annual fall floods began last night and will continue for a week. The annual spring floods will not begin for another 2-1/2 years.

This article states that the flow will be raised to about 43,000 cfs for the next week (which is about 5x normal). The process will help destroy shoreline vegetation that is overtaking beaches and will also assist in the restoration of the endangered humpback chub.

The NPS has notified boaters downstream that beaches may be inundated, and normal rafting speeds can more than double due to the increased flow.

The weeklong flow will drop the level of Lake Powell by 2-3 feet.

See real-time streamflow data at Lee's Ferry here: http://waterdata.usgs.gov/az/nwis/uv?site_no=09380000

Full article here: http://www.ouramazingplanet.com/3769-gr ... store.html

[desertgirl]

Wonder how it would be to ride big water ...

[Jim]

If only they could heat and muddy the water the rest of the year. I suspect from a hydrological engineering perspective, this is a useful time to flood, but in a dry year such as this, or any in year really, October and November probably had the lowest flows on the river, so this is probably the most flow the river ever saw at this time of year. Perhaps ever, or since the last man made flood, for November. I'm guessing, but it is a weird time for high water. Maybe this is also being done to raise water levels in Mead and ensure water will be there for Vegas to extract, winter crops, and boaters?

Actually, it is sort of impressive that they have water to do this, or not, but relatively speaking it is. Google street view has the Rio Grande full of water in their image of US 70 crossing the river, but when I drove over it in early October, the river was bone dry and people had been driving on the river bed. The 2 reservoirs north of Las Cruces were low, too. To think people complain about over allocation on the Colorado River. The Rio Grande was dry, and that is probably not even half way down it's length. That is probably like the Colorado being dry near Page.

[chumley]

Jim I wonder how much the timing has to do with the cost? The article states that the power that is not generated by water bypassing the dam/turbines and heading downstream has to be replaced by purchasing the equivalent power from other providers. Perhaps power consumption is pretty low at this time of year, thereby making the amount needed to bridge the gap much lower?

While the cost is spread across all the affected utility customers, apparently it will cost 1.5 million residents of Utah about $1.5 million for this flood, while past floods have cost them as much as $4 million! So the difference is only a couple of bucks per person, but still...

[chumley]

I just noticed that the National Weather Service has issued a Flood Advisory for the Grand Canyon. That's sort of funny. I knew that there was no rain anywhere in sight...
http://forecast.weather.gov/showsigwx.p ... d+Advisory

[Jim]

Must be something wrong with a dam up stream.

[Vaporman]

I had to postpone our MatKat canyoneering trip this extended holiday weekend do to this damn release.

[Espi]

Flood tests were conducted in 1996, 2004 and 2008. These three blasts helped rebuild beaches and protect native fish such as the federally threatened humpback chub, but the newly deposited sediment quickly eroded. Researchers also found that without sufficient sediment below the dam ­— dumped by the Paria and Little Colorado rivers ­— the reservoir water was too cold for the humpback chub to spawn.

This is confusing to me. Are they saying that these bigger releases will cure the water temp issues as well as stopping the eroding?

[outdoor_lover]

Probably, sounds like sediment = shallower water areas and pools = warmer water....?

[Jim]

Ironic, because I have heard the Glen Canyon dam was built in part to control sediment deposits into Lake Mead, as well as provide extra water storage and generate money by producing electricity; the so called cash register dams. Here they are saying they need the sediment in the river, and that eventually reaches Lake Mead, and faster with these large releases.

[Espi]

Probably, sounds like sediment = shallower water areas and pools = warmer water....?

The sediment deposits quickly eroded?? So its a temporary fix?

I dunno... I don't know enough about it really. It just seems like the damage was done a long time ago and the humans are grasping at straws in a lame attempt to fix something that may well be too far gone.

[outdoor_lover]

@Espi
Maybe that's why they decided to try a "Flood" at this time of year instead in the Spring. They're hoping that the Sediment will stay put and maybe even get "established" over the Winter.....

[BEEBEE]

When I rafted the river in the 90's before I moved to AZ we were on one of the first few trips after they started doing this. I remember how impressed the guides were with how many new beaches were along the river. The also could not believe how big some of the existing ones had become.