| Monitoring information is transmitted from the instruments to water department facilities in town. |
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.
