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HDR report: Shallow aquifer still might need reverse osmosis
by Gary Kent
Jul 16, 2013 | 1174 views | 0 0 comments | 24 24 recommendations | email to a friend | print
BEEVILLE – Citizens Committee members were told Monday evening that even if the city drills wells in the Evangeline aquifer, it may be necessary to filter that water by reverse osmosis.

Kristi Shaw of HDR Engineering told the full, 17-member committee that water from the shallower aquifer contains high levels of iron and manganese, depending on the location of a well.

Levels of those minerals vary from place to place within the Evangeline water sands.

That water, she said, could possibly require RO treatment.

When asked about the quality of water that could be used for an irrigation well, Shaw said irrigation wells often are drilled in shallower aquifers.

Wells that could provide enough water for used by a municipality are often deeper.

Shaw also said that state agencies would have water quality data on some of the locations outside the city. But she admitted that the city would have to get permission from landowners before it could drill a well on property outside of Beeville, and any agreement would require a lease between the city and the landowner.

When Shaw said the cost of raw water purchased from landowners would have to be negotiated, board member Jessy T. Garza questioned the HDR report.

“You can’t do a study without knowing what the costs would be,” Garza said. “We don’t even know if those landowners are even willing to sell (water)?”

“Correct,” Shaw said.

Garza then questioned the ability of the engineering firm to draw a conclusion from the data available regarding the aquifers.

Shaw said engineers could come to a better conclusion on the viability of certain wells with more and better data.

The engineer said a particular well site would have to be tested to determine the best place for a well.

Adan Perez, who retired from the city’s water department, said he knew that the Texas Commission on Environmental Quality gave Beeville permission in 2002 to use water from its existing wells.

He said the wells were still working as late as July 2008. He asked Shaw if the HDR report was based on existing data or on newly-developed information.

Shaw said that when the city requested the HDR study on groundwater sources, it asked the firm to collect old data, not to develop new data.

The engineer went on to say that no testing had been done on the existing wells. She did say that the condition of casings and other equipment at the wells is such that engineers do not think they could be used again.

When asked by board member Jim Crumrine about the ability of the wells to recharge around the Chase Field Industrial and Airport Complex and along the State Highway 202 corridor, where the city has an existing pipeline, Shaw said the local groundwater district would have that information.

She said that HDR was aware that only about half of the available groundwater in the shallower aquifers in that area is being used.

Garza then suggested that the situation with those aquifers could change in the next 25-30 years.

“That is true with any source of water, groundwater or surface water,” Shaw responded. “Energy costs could skyrocket, and that would increase costs.”

“Is there a reason you tend to be unfavorably disposed to RO?” Garza asked Shaw.

“I’m not unfavorably disposed to RO,” Shaw said. Then she listed some of the aspects of reverse osmosis that can make the filtering method expensive. Among those would be the costs of filtering membranes, the disposal of concentrate taken from the water and the costs of energy required to power the pumps in an RO plant.

Shaw said HDR asked the city staff early on if Beeville wanted them to study the costs of advanced treatment of water or to study potable water sources. She said the company was asked to look at potable water first.

Board member Tom Beasley then asked Shaw what information the company was able to obtain regarding the wells the city had used before it developed the surface water system.

Shaw said engineers had asked city employees about the wells, and the employees had no data.

“It’s important that the committee know that there is no information available on aquifers within the city,” Beasley said.

Shaw answered that it is important for municipalities to use both surface and groundwater sourses.

Board member Garry Cude said that if South Texas experiences another 10 years of drought, “we won’t have surface water.” He asked Shaw if the Evangeline aquifer would be able to supply the city with a suitable quantity of water.

“It would,” Shaw answered.

Shaw said there is brackish water in deeper aquifers, but there is a disposal cost for the concentrate created by any RO filtering. That would be required to make brackish water drinkable.

One of the situations favorable to Beeville regarding the disposal of what would be left over after RO treatment is that the city is close to the coast. Brine could be disposed of in the Gulf of Mexico.

“If you don’t have a low-cost option for disposal, it could be a problem,” Shaw said.

Committee Chairman John Galloway then asked Shaw if there would be any problem with water in an aquifer located beneath a former landfill.

He said one of the well sites proposed by those who want to drill new wells within the city would be at the site of a former landfill.

Shaw said that could be a problem if the landfill was used by industrial sources.

Garza then asked Shaw if she thought the falling level of Lake Corpus Christi should be a serious concern for Beeville.

The engineer said it could because of the location of Beeville’s raw water intake structure.

Shaw said droughts are inevitable in South Texas.

“Is planning going to help the city in the near future?” Shaw asked. “Probably not. It depends on when and if it rains.”

Shaw said the city also needs to consider life cycles. That means there are limits to how long items like filtering membranes and treatment facilities last.

Garza then asked if Shaw thinks conservation works.

“Yes,” the engineer said. The Texas Water Development Board has ideas on how communities can conserve water.

Committee members were scheduled to meet again at 6 p.m. on Thursday, July 11. They expected to hear reports from other engineering firms, including NorrisLeal Engineering Water.

That company is the one that has recommended the construction of an RO plant to filter suspended solids and chlorides from the brackish water in the Jasper aquifer.

Studies have shown the deeper aquifer has an abundant supply of water.

Gary Kent is a reporter at the Bee-Picayune and can be reached at 358-2550, ext. 120, or at reporter@mySouTex.com.
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