By Herb Fancher and Terry Engelhardt
Communities across the United States are concerned with increased oil and gas exploration and the potential impact on their drinking water supplies. Two communities in Western Colorado are taking a proactive approach by establishing a cooperative relationship with the companies working in their watersheds and are continuously monitoring the water sources that could be impacted.
The communities of Rifle and Parachute are located in Western Colorado along the Colorado River. This area of Colorado, rich in oil and gas, is known as the Piceance Basin.
Concern over possible contamination of their community water supplies is not new for residents of Rifle and Parachute. The heavily traveled Interstate highway I-70 and a busy rail line parallel the Colorado River in the area of these two communities. The highway and rail line have significant freight traffic which may include hazardous materials that could contaminate the river in the event of an accidental release.
Rifle, a city of approximately 9,200 as of 2011, relies on two water sources. The Graham Mesa water treatment plant treats water from the Colorado River and supplies approximately 90% of the city's water. The much smaller Beaver Creek facility treats water from Beaver Creek and supplies approximately 10% of the community's needs. According to Superintendent Robert Burns, Rifle's citizens typically use about 600,000 gallons per day during the winter. Peak summer demand can reach nearly 4 million gallons per day.
Rifle's primary concern for possible contamination in the Beaver Creek watershed is from oil and gas exploration. Access roads in the terrain beyond the diversion structure are unimproved and there is potential for accidental spills. This concern was expressed to the exploration companies during the permitting process and the companies agreed to fund acquisition and installation of monitoring instrumentation in the headworks house at the intake structure.
If contamination is detected by the instrument array, an alarm is sent to the operations staff and the water is automatically diverted away from the intake until the alarm is investigated.
"The companies have been very good to deal with," Burns said. "I'm normally among the first people they call if they suspect anything might negatively influence our water."
Hach Company's Source Water Monitoring Panel (SWMPsc) was selected for the majority of the monitoring needs. The panel's flexible design permits users to select six sensors from many different measurement parameters including pH, turbidity, solids, conductivity, oil in water, UV transmittance, nitrate, dissolved oxygen, ORP, ammonia, and temperature. In so doing, users achieve a customized system for an off-the-shelf price that is configured for their particular need.
For monitoring Beaver Creek, the sensors selected included pH, turbidity, ORP and conductivity. A hydrocarbon analyzer from another manufacturer also was installed. The sensors all connect to the Hach sc1000 digital controller. Signals from the controller are transmitted via radio to the water utility offices so the instruments and the water quality can be monitored remotely.
"It takes us nearly a half hour to reach the site so it's important to be able to monitor the instruments and the water quality remotely," Burns said.
To date, no accidental spills into the water have been reported or detected.
Parachute is a town of approximately 1,085 as of 2011. The town's water treatment plant has a capacity of 0.5 million gallons/day to treat water from the Colorado River. The town also has a spring water source used during the summer months.
Parachute had good reason to be concerned with contamination from oil and gas exploration. At least four spills occurred northwest of Parachute along Parachute Creek in late 2007 and 2008. Even though Parachute's water treatment plant is located above the confluence of Parachute Creek and the Colorado River, Parachute water officials were concerned. The town and others potentially impacted were not notified immediately. Fines were imposed on the firms responsible. A win-win agreement resulted in a portion of the fines being used to purchase monitoring equipment for the Town of Parachute's water treatment plant.
According to water system operator Dan LaRue, agreement was reached with the state, the town and the firm responsible for one of the spills to purchase monitoring equipment for the town in lieu of simply placing the fine in state coffers. The Hach Source Water Monitoring Panel was selected. It is located at the water treatment plant and continuously monitors the source water for the community.
Sensors selected for Parachute's monitoring needs included oil-in-water, pH, conductivity and turbidity. All sensors are connected to the Hach sc1000 Controller. The controller also provides outputs to the treatment plant's main control system.
A Hach Sigma refrigerated automatic sampler also was installed. According to LaRue, if values from the oil-in-water probe exceed a selected set point, a signal is sent from the controller to the automatic sampler to immediately begin sample collection.
The automatic monitoring and sampling is important as the utility department has a small staff of four people with a variety of other tasks in the community.
The source water from the Colorado River is initially pumped into a small storage tank. The water is then treated by the membrane system in the treatment plant. Should the instrument array detect a problem, the raw water pump is stopped until the cause of the problem can be investigated. In the meantime, the treatment plant can continue to operate from water in the storage tank. The good news is no events have been detected since the instrument array has been installed.
About the Authors: Herb Fancher is Regional Sales Manager at Hach Co. Terry Engelhardt is Application Development Manager, Drinking Water, at Hach. Special thanks to Robert Burns, City of Rifle, and Mark King and Dan LaRue, Town of Parachute, for providing information and giving their time to review the document. Photographs by Terry Engelhardt, Hach Co.