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You’d think the Harlingen WaterWorks System (HWWS) would be sweating bullets over the severe drought the south Texas city of 80,000 has been suffering through for more than two years. It’s not, thanks to good planning and a no-nonsense approach to water management. 

In fact, Water Services Director David Sanchez says HWWS hasn’t made any changes to the water treatment system as a result of the drought, which has hit Harlingen and surrounding communities hard, prompting water restrictions in many areas. Harlingen gets its water directly from the Rio Grande River, which flows from southwestern Colorado to the Gulf of Mexico, forming part of the U.S.-Mexico border. Raw water is pumped out of the Rio Grande into an irrigation canal system and then is gravity fed straight down to the city’s reservoirs. 

Water stays the same

HWWS operates two water treatment plants: a 20 mgd conventional facility, known as the M.F. Runnion Water Treatment Plant, which uses sand filters and a traditional alum and polymer blend and other chemicals to promote sedimentation, and a newer, compact 15 mgd ACTIFLO unit (Veolia Water Solutions & Technologies), the Downtown Water Plant, which employs a rapid settling process for clarification. Other than fluctuating salinity levels caused by faulty pumps and other issues on the Mexican side, Harlingen’s water remains unchanged. 

“We don’t see the drought as having much of an impact on the water we get from the Rio Grande,” explains Sanchez, who’s led HWWS for the last four years. “The Rio Grande water changes all the time; that’s the way it’s always been. If you have significant rain, you get one quality of water; if you don’t get enough rain, you get another type, so we’re used to dealing with the ever-changing water quality. You just have to watch it and change your chemicals accordingly.” 

Fewer chemicals used

Change is what the straight-talking Sanchez has done since taking over the water treatment system. The M.F. Runnion plant, for example, doesn’t use the traditional oxidizers most communities use to treat water. Instead, it uses peroxide — one of the few in Texas to do so — along with an alum/polymer blend and chloramines. According to Sanchez, the results have been excellent: no odor or taste issues in four years. 

“We had been using about eight different chemicals, and now we’re down to three and producing better-quality water,” Sanchez says. “Because of the rapid sedimentation process at our Downtown plant, we have to use more traditional chemicals and a cationic polymer for the settling process to work, but we’re moving toward changing that so we can use peroxide and reduce the number of chemicals.” 

Communities face shortages

The drought is having a major effect on communities that haven’t secured water rights and are running out of water, which is not the case in Harlingen. “HWWS management has done an excellent job in planning and has secured more than enough water rights to meet our needs,” Sanchez says. “As long as there’s water in the river, our customers will have water. Right now, we haven’t seen a change in water quality. Our traditional NTUs in the raw water coming in are about 80 and holding steady. If we see the NTUs getting higher, we’ll have to make some chemical dosage adjustments, but at present, that’s not the case and we monitor it constantly.” 

The Harlingen WaterWorks System serves about 24,000 customers and has five wholesale customers. Some of the smaller towns depend on HWWS water supply and maintain an active connection; other surrounding communities have expressed interest in connecting because of the drought. 

As for Sanchez, he’s hoping Harlingen and other communities in the Rio Grande Valley get showers in May to mitigate the effects of the drought. Meantime, he and his team will continue to keep an eye on the Rio Grande and be thankful the water is still there.


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