FROM AGFC Trout Biologist Christy Graham:
As you may recall, I sent you all an e-mail last month regarding round the clock generation on Norfork. Since that e-mail, the Corps has not been able to get the lake down to an elevation of 553 ft.
In order to make another attempt to drop the elevation in the lake, the Corps opened a sluice gate on Norfork Dam this a.m. (see attached press release).
Using the sluice gate is just one option to try and get water out of the lake faster. The other option is to release additional water through the spillway gate. The spillway gate option would not be preferred, since water temperatures in the lake on the surface are very warm (over 80 F).
We (Trout Program personnel) were on the river this morning to monitor temperature and Dissolved Oxygen levels both before and after the sluice gates were opened. Dissolved oxygen levels were actually improved and temperature was lowered.
The only negative was that the water became quite murky when they started to make the release. Although a nuisance to fisherman, murky cold water is much better than hot, clear water for the trout.
You may also notice that the siphon will be running around the clock for the time being. Nothing is wrong with it, it is just another way to get more water out of Norfork Lake.
Since this is the first time they have used this type of release for water, they are only going to do it on weekdays (Mondays-Thursdays) for about 8-10 hours when folks are working in the dam and able to monitor the releases. They will not release from the gate Fridays to Sundays or on the 4th of July.
My contact estimates it will take up to two weeks to get elevation down, barring any more major rains between now and then. If they didn’t do alternative releases, it could take up to a month or more to release the water to the level they need to get that gate fixed.
Click Through For the USACE Press Release
CORPS BEGINS RELEASE THROUGH SLUICE GATE ON LAKE NORFORK
MOUNTAIN HOME, Ark. — The Army Corps of Engineers began releases this morning thought one sluice gate of Norfork Dam to augment water releases from a hydropower turbine.
The sluice gate releases began around 11 a.m. today and will occur for up to 10 hours per day, Monday through Thursday, until the lake is lowered to elevation 553. The total release mirrors a typical release through both hydropower turbines at full power. The one hydropower turbine will remain in constant full power throughout the day.
Corps personnel will reevaluate the release schedule if heavy rains occurs in the watershed.
Corps personnel will continue monitoring water quality. Dissolved oxygen levels have been boosted with sluice gate releases.
One of the two hydropower turbines at Norfork Dam is undergoing rehabilitation work on the intake gate. One lane of the Highway 177 across Norfork Dam was closed to allow for equipment used in the rehabilitation work. That closure has been lifted. Once the lake level is lowered enough to allow work to continue, a notice about an addition lane closure will be published.
Boaters near the dam are advised to use extra caution since sluice gate releases are higher velocity than hydropower releases and very turbulent.
For more information about Norfork Lake call 870-425-2700.