Drainage official expects rainfall will exceed capacity

 McALLEN - If rainfall from Hurricane Dolly is as heavy as feared, the region's drainage system will not be able to cope, county officials said Tuesday. 

Additionally, if Dolly veers into Mexico as forecasters now predict, Hidalgo County officials fear that several Mexican dams could overflow, spilling large amounts of water into the Rio Grande. That surge, officials fear could push dams along the river past capacity, said Hidalgo County Judge J.D. Salinas.

The U.S. International Water and Boundary Commission, which owns and operates the levees here, expressed no concern Monday afternoon that dams on either side of the Rio Grande would reach capacity, according to Sally Spener, IBWC spokewoman.

At 10 p.m. Tuesday, the National Weather Service was predicting six to ten inches over the next few days with up to 15 inches in isolated areas. In the event even six inches of rain falls in a 24 period, drainage channels might overflow, said Hidalgo County Drainage District Director Godfrey Garza

"Especially in the short timeframe they're talking about," he said. "We've been doing alright this summer, but it's been over a longer period of time."

If the storm heads toward the mountains near Matamoras, Tamaulipas, Mexico, the potential for heavy flooding increases, he said.

Meanwhile, the hardest hit areas from Dolly's expected initial rainfalls will be the northern and eastern parts of the county.

"As we start moving further downstream the flooding will be worse," Garza said. "Our system is like a network of roadways and they all feed into the main channel."

More westerly areas, including Mission and McAllen, are expected to fare better.

"We'll probably see some flooding but not as bad as other jurisdictions," said McAllen Assistant City Manager Pilar Rodriguez. "South of Expressway 83 will be most prone (to flooding)."\

Crews were at work Tuesday night checking drainage systems across the county.

"It's dry right now," Rodriguez said.