The following is the Boyce Hydro, LLC update on the status of the seepage area at the Sanford Dam as of our inspection of 7 am today, Tuesday, September 7th.
We started monitoring the seepage areas, drain tiles, and embankment piezometers three times a day on August 14th. The current status of the Sanford Dam embankment project is as follows:
1. The pond level is down to 627.15 which is 3.65 feet below normal pool.
2. Monday night the Sanford Dam area received 0.2 inches of rain. The ground is damp but there is no sign of standing water. This small amount of rain has not had any noticeable effect on the drain pipes.
3. All previously manifested seepage areas and the embankment itself have dried up.
4. Ten of the 23 drain tiles have dried up and most others have shown a decrease in flow.
5. Sand bleeding was initially identified in 5 drain tiles. All of these five tiles have stopped bleeding sand.
6. Since the last Boyce Hydro, LLC report the water level in the temporary upper embankment observation well has dropped 0.2 feet. The level in the middle well has also dropped 0.2 feet. The level in the lower well did likewise but has come back up 0.1 feet with last night’s rain.
7. Since the last report the water level in the upper embankment piezometer has dropped 0.1 feet and the lower one has dropped 0.05 feet.
8. Approximately 400 cubic yards of special sand mix have been stockpiled at the staging area near the West end of the Sanford Dam.
9. Approximately 400 lineal feet of 3” diameter Schedule 40 slotted drain pipe has been delivered to Boyce Hydro for the repair project. An additional 200 lineal feet of this pipe are on order. Also on order are 360 lineal feet of 12” diameter Schedule 40 slotted drain pipe as well as a 4’ diameter concrete manhole with fittings and cover. The Boyce Hydro, LLC excavation contractor will be mobilizing equipment on site at the Sanford Dam next Monday, September 13th. The initial phase of construction is expected to take about two full weeks.
10. An expansion of the scope of work now required by the FERC for the project may extend the time of completion until the end of October. Certain Civil Engineering details pertaining to the expanded scope of work are under discussions with FERC.
There is little doubt that lowering the impoundment has had a positive and beneficial impact on the condition of the embankment. Boyce Hydro, LLC intends to keep the level of the reservoir between 3.5 and 4 feet below normal pool until construction is completed at the end of October.
Lee W. Mueller, Architect & Co-Member Manager
Boyce Hydro, LLC
6000 South M-30 (P.O. Box 15)
Edenville, MI 48620
tel: (989) 689-3161 / fax: (989) 689-3055