BMA responds to worries in Bandera - Part I
By William Hoover Courier Contributor
(Editor's note: This is Part I of an interview with BMA Business Manager Ed Berger)
The Bexar-Medina-Atascosa Water Control and Improvement District's recently approved well and tributary flow studies around Medina Lake are not being conducted in an attempt to gather data to wrest control of groundwater in Bandera County. BMA also has no objection to the Bandera County River Authority and Groundwater District moving its election to November, according to BMA business manager Ed Berger who was responding to concerns expressed last week by local elected officials.
Custodians demand accounting
As the custodian of the dwindling lake, Berger said BMA is conducting the studies in an attempt to account for water stored behind Medina Dam, which they are responsible for as a WCID having obligations to district members. The lake, designed to hold a 254,884 acre-feet of water, was around 5.8 percent capacity and 82 feet below the spillway as of Tuesday, April 23.
"When we have a situation where the lake is going dry and farmers are being harmed financially, we need to make sure we know what is happening to the water," Berger said of the need for the well and tributary studies to identify sources of water loss in the lake other than evaporation and seepage into the Edwards Aquifer.
"In March, no less than 21 acre feet of water day was coming into the lake via the Medina River through the station in Bandera and we were only taking out 14 acre feet a day (for delivery to SAWS) but the lake still went down 3,000 acre feet," noted Berger of drops in the lake level despite the 7 acre-foot positive inflow. "We know there is a calculated amount of evaporation. But what has happened to the rest of the water?"
Shallow wells & ponds affect lake water?
The BCRAGD is supposed to ensure wells around the lake are drilled to a depth of 600 feet to draw from the Lower Trinity Aquifer. Shallower wells would actually draw water from the lake, according to the BMA manager.
"We hear all the stories about the wells going dry when the lake goes down," he noted. "So where is that water coming from? We just want to know what is happening to the water."
Medina Lake has a small watershed and storage basin and, if the upstream tributaries are blocked, it will affect the recharge to the lake. Thus, BMA's tributary study will determine how much water is being impounded upstream in private ponds, thereby reducing rainfall recharge into the lake.
"In 2012, we had significant rain events in January and February," said the BMA business manager. "In the past, if we had those rain events in that basin north of the lake, you'd have seen an immediate rise in the lake. But these rain events had hardly any effect on the lake. What we think is happening is, every one of these little dams upstream were filling up with water because they were dry from the drought. But we can't say that without a professional study to compare the total impoundment 10 years ago to the total impoundment today."
Berger continued, "Once we have that data, we could take it to somebody like the Texas Commission on Environmental Quality and say we need to work together with (BCRAGD) and maybe take some of those dams out.
"Or maybe we need no more new dams, or to take all the dams off the river. We need to know about the effects of damming tributaries and study all the wells because those two things have a direct affect on our lake. There is no mystery here. The lake is almost empty and we need to know what the situation is with the water."
Lack of metering
Regarding claims water constantly flows from the lake un-metered, Berger notes BMA meters its water from a release point at Diversion Lake Dam, not Medina Lake Dam.
"The people up there think it should be metered coming out of Medina Dam, and not below Diversion Dam," he said. "It is all one system, so it doesn't really matter where we meter from. I had a group in here from the lake Thursday, April 18, and I showed them our engineering studies from 2007 to show them the exact effect. They thought all the water was going out of Diversion Lake down into recharge features, but it is not."
Look for Part II of this interview in next week's Courier.