Why are ASR system improvements needed?
The improvements are needed now to address potential water quality concerns. The new treatment processes will adjust the pH of the water to minimize the corrosion of lead and cooper from household plumbing. The Oregon Health Authority - Drinking Water Services is requiring the City have the ASR water treatment facility built by the end of the Summer 2021.
The City's ASR system provides a critical backup supply for the City's primary source of supply, the North Santiam River at Geren Island. The four existing ASR wells in the park can supply between 5 and 8 million gallons of water per day (mgd) which helps offset increased water demand during the summer when water use is higher. The ASR system improvements will create capacity to store enough water to serve the City in the event that the primary source of water has a disruption of service.
ASR is the most economical approach to increasing water system redundance and reliability. The improvements to the ASR system include planning for future wells, both within Woodmansee Park and at future locations, will expand the capacity of ASR as a backup supply up to 20 million gallons per day.
Why does the ASR system expansion need to be in Woodmansee Park?
During the preliminary planning for this project, the City evaluated alternative sites to locate the Treatment Facility. Criteria used to identify alternative sites included land availability, access and size requirements, location near the existing City's water infrastructure, and cost for the treatment facility. Woodmansee Park was determined to be the best location.
What will the ASR treatment facility include?
The ASR water treatment facility will include equipment for improved disinfection and pH adjustment of the drinking water before it is delivered to the public. Around the new building, additional improvements will be made including landscaping and fencing, a stormwater detention facility, and a dedicated access road off Sunnyside Road SE for maintenance vehicles and deliveries. Stormwater runoff from the site will be collected and delivered to a new stormwater outfall to Pringle Creek.
How will existing park features be impacted by the ASR improvements?
The new ASR water treatment facility will be located in an area of the park that is currently open space. Two holes on the disc golf course will be temporarily closed during construction in the northeast area of the park. The layout of the disc golf course will be modified to go around the facility. A new sidewalk will be constructed from the treatment facility to the main park driveway east of the soccer field.
Trees will need to be removed in the vicinity of the proposed ASR treatment facility. New trees will be planted, and landscaping will be added to provide a buffer and treatment of stormwater runoff. An existing footpath will need to be relocated around the treatment facility.
Driveways to access the new ASR wells are needed and will be integrated with park trails and walkways where practical.
Other impacts during construction will be temporary such as excavation for pipeline construction. A portion of the east side of the soccer field may have temporary closures for short periods of construction activity to build the sidewalk and piping east of the edge of the field.
Does the Woodmansee Park Master Plan update include the Phase 2 ASR well locations?
The Woodmansee Park Master Plan update includes the anticipated well locations. Construction of the ASR wells and master plan improvements will be coordinated to minimize impacts to both the ASR system and Woodmansee Park.
Will the new ASR treatment make the tap water taste better?
Not necessarily. The ASR System allows the City to store water in a natural underground aquifer and recover that water when needed. Water is typically stored in the aquifer for several months resulting in some taste and smell differences as the stored surface water mixes with native groundwater in the aquifer. Typically, recovered water supplies about 15% of the City's water supply during summer months so the result is that drinking water should taste similar to the tap water you normally receive from the City's North Santiam River surface water supply, however some customers are able to detect a change in the taste.
What is the cost of the ASR improvements and how are they funded?
The initial budget for the ASR project is $11.5 million dollars, funded through water rates. The City has these funds set aside for the new water treatment facility and associated improvements that are included in Phase 1. The cost of the additional wells that are part of Phase 2 will be determined through design.
The state legislature recently approved funding for the City's ongoing improvements to supply safe and resilient drinking water.
Can the aquifer withstand increased use?
One of the benefits of an Aquifer Storage and Recovery (ASR) system is the ability to withstand increased use. During winter and spring when ample surface water is available, the ASR system recharges the aquifer with treated drinking water from the City's primary water source (the North Santiam River supply at Geren Island). During the summer, when water is being used from the ASR wells, the volume pumped from the wells will always be less than the volume that has been stored (this is a legal requirement for ASR systems). To ensure that the aquifer is not negatively impacted by the use of the ASR, the City monitors aquifer water levels for both recharge and recovery. This data is provided to the State of Oregon Water Resources Department annually.
How much of Pringle Creek's water gets into the aquifer?
Pringle Creek flows do not infiltrate the ASR supply. The aquifer we are recharging and recovering water from is a deep confined basalt aquifer. This means that there are several layers of impervious material (typically clay and silt layers) between the creek and the aquifer that prevent the migration of water from Pringle Creek to the aquifer and from the aquifer to Pringle Creek.