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County encounters dam problems

By Judith Pannebaker BCC Editor

Photo by Mike Crandall
The Medina Lake spillway over-topped at 6:37 am on Tuesday, May 31, 2016.

Bandera’s nearly 10 inches of rain last weekend raised as many questions as it did the water levels behind dams in Bandera County.
According to County Judge Richard Evans, the spillway at Medina Lake Dam functioned as it was designed, to let the water out – which it did with alacrity.
The water in Medina Lake, which at its lowest only represented 3 percent capacity, exceeded the conservation pool level. At midnight on May 30, the water level was at 1064.2 feet. On June 1, it had risen to 1065.7 feet. By Monday, June 6, the level was down to 1065.3. Elevation to the top of the dam is 1076.2.
Regardless of it functionality, the Medina Lake Dam which celebrated its 100th anniversary in 2012, is being monitored closely not only by officials in Bandera and Medina counties, but also by administrators with the Texas Commission on Environmental Quality (TCEQ) and staff with the BMA (Bexar-Medina-Atascosa Counties Water Improvement District No. 1) and the Bandera County River Authority and Groundwater District.
According to US Geological Survey monitoring gauge on the Medina River, water discharge on May 31 was 8,000 cubic feet per second. On Monday, June 6, it had slowed to 1,000 cubic feet per second. At flood stage, water is discharged at 13,000 cubic feet per second.
Also, causing consternation during last weekend’s downpours was a pair of private dams in the Twin Lake subdivision, located on Highway 173 North. “While the dams did not fail, the backsides were washed out,” Evans said. Additionally, the lower of the side-by-side dams was overtopped by water.
According to Precinct 3 Commissioner Andy Wilkerson, to alleviate the could-become critical situation, he and Precinct 4 Commissioner Jordan “Jody” Rutherford rented two eight-inch pumps from oil fields in Diley, following advice from TCEQ officials. Once set up, the pumps accounted for 6,000 gallons of water per minute being pumped from Twin Lake into Jack Hollow Creek.
Wilkerson said water was reported spilling over the dam during the height of the deluge on Sunday, May 29. “We called TCEQ on Monday morning and they sent a representative to inspect the dams on Tuesday. Something had to be done,” Wilkerson said.
Although the dams are private, in the interest of public health and safety, it became incumbent on Bandera County officials to “do that something” such as procuring the heavy-duty pumps, which did more good on Twin Lake than the oil fields of South Texas.
Wilkerson said the pumps were installed on Wednesday night and ran continually until the morning of Sunday, June 5. During that time, more than a million gallons of water were discharged into Jack Hollow Creek.
The alternative was not very pretty.
According to Evans, if the dams failed, water would have poured into Jack Hollow Creek and eventually into Bandera Creek. “During last weekend’s rain, Bandera Creek had already flooded Highway 16 South and took out some trailers and pickups,” Evans said, leaving the rest of the scenario to the imagination.
Although no flooding was reported in homes clustered around the lake and no appreciable rain is in the forecast, the dams at Twin Lake must undergo further scrutiny.
“Ten year ago, TCEQ officials told the developer those dams had to be improved, but nothing was done because there was no enforcement,” Wilkerson said. “This time somebody will have to do something about them.”
He noted that TCEQ officials planned to require a hydraulic report on the dams, which would be submitted to commissioners court. “We’ll find all about it then,” Wilkerson said.
In the meantime, only local traffic is being allowed to cross the road topping the dam, but heavy truck traffic is prohibited.