Sinkholes, seeping dams concern water officials

A team of researchers is trying to get to the bottom of potential problems at Amistad Dam.

The dam, one of two reservoirs that store water for the Rio Grande Valley region, was declared "potentially unsafe" in an inspection report released by the U.S. Section of the International Boundary and Water Commission last year. The report recommended further study and inspections at the dam.

Since then, the agency, which oversees reservoirs and levees on the U.S.-Mexico border, has put together a research team that will study the risks at Amistad and make recommendations, IBWC Commissioner C.W. "Bill" Ruth said at a meeting Wednesday.

"We need to do a lot more work to determine the conditions (at Amistad) and what the repairs need to be," Ruth said.

Inspectors' main concern at Amistad, which is in Del Rio, is a cluster of naturally occurring sinkholes in the reservoir, through which water is escaping, Ruth said.

The team likely will need to look at the geophysics of the dam's foundation and determine why the sinkholes are occurring, as well as determining where the water is going, officials said.

Although the sinkholes are cause for some concern, there is no immediate danger of flooding or breakage, Ruth said.

"We are monitoring this dam and what we see right now is no change (from past conditions)," he said.

Officials said Wednesday they weren't sure what repairs would be needed or how much they would cost.

Inspectors also determined that Falcon Dam, northwest of Roma, was "conditionally unsafe" because of concerns about seepage. IBWC is monitoring the reservoir's levels to determine how much water is being lost. If the agency determines repairs are needed, those will likely take place in 2010, officials said.

Melissa McEver covers health and environment issues for Valley Freedom Newspapers. She is based in Harlingen and you can reach her at (956) 430-6252.