Potable Water Collection, Treatment, and Storage in Ridgway Colorado
Overview: In 2022, the Ridgway Water Treatment Plant made roughly 7 million gallons of moderately hard drinking water. The plant conforms to State of Colorado guidelines, treating and then testing the water as specified. All test results fell within acceptable state ranges. A publication with annual testing results can be found on the Ridgway web site here. The plant is automated with an on-line interface that can display alarms and allows the operator to shut the plant if necessary. The plant’s alarms were upgraded in 2023.
Water Source: Surface water from intakes on Beaver Creek and Cottonwood Creek (aka Happy Hollow) provide Ridgway's current major potable water source. The Town has water rights to 1,365 acre feet/year of water from Beaver Creek and Cottonwood Creek.
Holding/Settling Ponds: 15-18 million gallons are held in 3 ponds at the treatment facility. Water generally flows into the larger pond (8-12 feet deep), through the small second pond, and into the 16-18 feet deep third pond.
Backup reservoir: Water from Lake Otonowanda is currently our back-up storage for drought years. The lake is located 3 miles S of Ridgway off CR-5 and is filled with water diverted into a natural basin via the Ridgway Ditch. It was expanded and the outflow was repaired in 2014-2015 so that water can exit and flow the several miles down to the Ridgway treatment facility. The Lake Otonowanda Rehabilitation allowed the town to exercise its full decreed storage right there by improving the lake’s capacity roughly sevenfold, from 109 to almost 750 acre feet.
Chlorine Dioxide Pretreatment: Following initial straining, chlorine dioxide is injected into the water. It binds with and helps remove carbon compounds, helping improve the color, taste, and odor of the water. While using this pretreatment, the facility is required to test daily for chlorine and chlorine dioxide residues. In 2023, the Town made the decision to switch to pretreatment with a granulated activated carbon (GAC) filter.
Treatment (Ultrafiltration): Water is pumped into one of four filtration units, each containing 24 tubes. Those tubes each contain 14,000 microfibers (plastic filaments 0.01 microns in diameter with microscopic holes). Water is pushed through these tubes, catching any debris/particles. While the filtration rate of the entire system is rated up to 500 gal/min, the system is usually run at about 175 gal/min in the summer and around 130 gal/min in the winter (due to slower filtration of cold water as well as less water demand).
Filter Maintenance: The system automatically scours the filter tubes with pressurized air every 30 minutes of run-time to flush away debris, turbidity, and scale. At least every 30 hours of run-time, the system goes through a more intense cleaning cycle with either a chlorine soak and flush (3 of 4 cycles) or (every fourth cycle) a cleaning with a warm citric acid soak (at pH 4.5) and flush. Every 720 hours of run time, an extended (5-9 hour) cleaning cycle is done with warm citric acid and water. Daily, the system does an integrity test, filling the tubes with air. If leakage is detected, signifying one or more microfibers have failed and have expanded pore-size, operators receive an automated alarm message, an automated process takes that tube off-line, and operators later test and identify the failed microfiber(s). The faulty microfiber is then sealed/blocked to prevent water from flowing through it. These tubes were initially anticipated to have a life of up to 15 years, but they were replaced (after 10 years) in 2017 and replacement in 2027 is anticipated.
Treatment (Chlorination): Chlorine (Cl) is the only chemical currently added to the water. Following filtration, the system automatically adds Cl to kill microorganisms. The system monitors the Cl level which seems to run between 0.96 and 0.98 ppm (a Cl level up to 4 ppm is allowable but would be less desirable). Flouride is not added to the water although the natural flouride level in the water is reported to run 0.3-0.4 ppm.
Treated Water Testing: The current system is 100% computerized so there is ongoing frequent testing of Cl levels, water temperature, and pH. There are automated measurements done every four hours of chlorine levels in the water entering the storage tanks and of chlorine levels and turbidity in the outflow water. The system has an automated phone alert system to notify the operators of any problems. Testing is done according to standards set down in the 1974 Federal Safe Drinking Water Act and 1996 amendments which regulate the quality of drinking water. Total coliforms (bacteria) are tested monthly and have been negative. All past yearly tests for lead and copper have been negative so the system is now on a 5-year testing cycle for those metals. Both the EPA and the State of Colorado have websites that address potable water testing. Per federal regulations, the Town of Ridgway is required to provide an Annual Drinking Water Quality Report to the public that gives information on the results of their water monitoring program. The drinking water Consumer Confidence Report is available at the Town Hall or online on the Town website. The Town has remained in compliance with all State water quality regulations with no violations in their water monitoring. The water has also been tested in the past for PFAS and PFOS and was negative.
Treated water storage and delivery: There are two 300,000 gallon tanks on site. There is a third tank in Vista Terrace with a 10,000 gallon capacity, which serves the upper pressure zones in that subdivision. In total, there is 610,000 gallons of total treated water storage when these tanks are full. During the summer, the Town can consume one of these large tanks in a day. During the winter, it usually takes 2-3 days to consume one tank. The Town occasionally runs into a problem with a leaky water line but those are infrequent and there are no apparent ongoing issues.
Treatment plant capacity and classification: The treatment plant generally filters and treats 350 gallons/minute in the summer and 200-250 gallons/minute in the winter. (The lower winter-time capacity is because colder water takes longer to filter.) CO water treatment facilities are divided into A, B, C, and D categories. The Ridgway water treatement facility is classified as a level "B" water system based on the volume ("units served") and the types of water treatment processes applied.
Overview: In 2022, the Ridgway Water Treatment Plant made roughly 7 million gallons of moderately hard drinking water. The plant conforms to State of Colorado guidelines, treating and then testing the water as specified. All test results fell within acceptable state ranges. A publication with annual testing results can be found on the Ridgway web site here. The plant is automated with an on-line interface that can display alarms and allows the operator to shut the plant if necessary. The plant’s alarms were upgraded in 2023.
Water Source: Surface water from intakes on Beaver Creek and Cottonwood Creek (aka Happy Hollow) provide Ridgway's current major potable water source. The Town has water rights to 1,365 acre feet/year of water from Beaver Creek and Cottonwood Creek.
Holding/Settling Ponds: 15-18 million gallons are held in 3 ponds at the treatment facility. Water generally flows into the larger pond (8-12 feet deep), through the small second pond, and into the 16-18 feet deep third pond.
Backup reservoir: Water from Lake Otonowanda is currently our back-up storage for drought years. The lake is located 3 miles S of Ridgway off CR-5 and is filled with water diverted into a natural basin via the Ridgway Ditch. It was expanded and the outflow was repaired in 2014-2015 so that water can exit and flow the several miles down to the Ridgway treatment facility. The Lake Otonowanda Rehabilitation allowed the town to exercise its full decreed storage right there by improving the lake’s capacity roughly sevenfold, from 109 to almost 750 acre feet.
Chlorine Dioxide Pretreatment: Following initial straining, chlorine dioxide is injected into the water. It binds with and helps remove carbon compounds, helping improve the color, taste, and odor of the water. While using this pretreatment, the facility is required to test daily for chlorine and chlorine dioxide residues. In 2023, the Town made the decision to switch to pretreatment with a granulated activated carbon (GAC) filter.
Treatment (Ultrafiltration): Water is pumped into one of four filtration units, each containing 24 tubes. Those tubes each contain 14,000 microfibers (plastic filaments 0.01 microns in diameter with microscopic holes). Water is pushed through these tubes, catching any debris/particles. While the filtration rate of the entire system is rated up to 500 gal/min, the system is usually run at about 175 gal/min in the summer and around 130 gal/min in the winter (due to slower filtration of cold water as well as less water demand).
Filter Maintenance: The system automatically scours the filter tubes with pressurized air every 30 minutes of run-time to flush away debris, turbidity, and scale. At least every 30 hours of run-time, the system goes through a more intense cleaning cycle with either a chlorine soak and flush (3 of 4 cycles) or (every fourth cycle) a cleaning with a warm citric acid soak (at pH 4.5) and flush. Every 720 hours of run time, an extended (5-9 hour) cleaning cycle is done with warm citric acid and water. Daily, the system does an integrity test, filling the tubes with air. If leakage is detected, signifying one or more microfibers have failed and have expanded pore-size, operators receive an automated alarm message, an automated process takes that tube off-line, and operators later test and identify the failed microfiber(s). The faulty microfiber is then sealed/blocked to prevent water from flowing through it. These tubes were initially anticipated to have a life of up to 15 years, but they were replaced (after 10 years) in 2017 and replacement in 2027 is anticipated.
Treatment (Chlorination): Chlorine (Cl) is the only chemical currently added to the water. Following filtration, the system automatically adds Cl to kill microorganisms. The system monitors the Cl level which seems to run between 0.96 and 0.98 ppm (a Cl level up to 4 ppm is allowable but would be less desirable). Flouride is not added to the water although the natural flouride level in the water is reported to run 0.3-0.4 ppm.
Treated Water Testing: The current system is 100% computerized so there is ongoing frequent testing of Cl levels, water temperature, and pH. There are automated measurements done every four hours of chlorine levels in the water entering the storage tanks and of chlorine levels and turbidity in the outflow water. The system has an automated phone alert system to notify the operators of any problems. Testing is done according to standards set down in the 1974 Federal Safe Drinking Water Act and 1996 amendments which regulate the quality of drinking water. Total coliforms (bacteria) are tested monthly and have been negative. All past yearly tests for lead and copper have been negative so the system is now on a 5-year testing cycle for those metals. Both the EPA and the State of Colorado have websites that address potable water testing. Per federal regulations, the Town of Ridgway is required to provide an Annual Drinking Water Quality Report to the public that gives information on the results of their water monitoring program. The drinking water Consumer Confidence Report is available at the Town Hall or online on the Town website. The Town has remained in compliance with all State water quality regulations with no violations in their water monitoring. The water has also been tested in the past for PFAS and PFOS and was negative.
Treated water storage and delivery: There are two 300,000 gallon tanks on site. There is a third tank in Vista Terrace with a 10,000 gallon capacity, which serves the upper pressure zones in that subdivision. In total, there is 610,000 gallons of total treated water storage when these tanks are full. During the summer, the Town can consume one of these large tanks in a day. During the winter, it usually takes 2-3 days to consume one tank. The Town occasionally runs into a problem with a leaky water line but those are infrequent and there are no apparent ongoing issues.
Treatment plant capacity and classification: The treatment plant generally filters and treats 350 gallons/minute in the summer and 200-250 gallons/minute in the winter. (The lower winter-time capacity is because colder water takes longer to filter.) CO water treatment facilities are divided into A, B, C, and D categories. The Ridgway water treatement facility is classified as a level "B" water system based on the volume ("units served") and the types of water treatment processes applied.