CITY OF ASHLAND WASTEWATER TREATMENT PLANT Temporary Drawdown of Ashland Pond
The City of Ashland is relocating the outfall of the Wastewater Treatment Plant (WWTP) from Ashland Creek to Bear Creek to comply with new state water quality regulations. The outfall is the location where treated water from the WWTP is discharged into the creek. The City is in Phase II of the project, which includes final engineering design, bidding, and construction preparation at Ashland Pond. Users of the Ashland Pond Park may notice a gradual drawdown in the pondís water elevation in upcoming months. Temporary dewatering of Ashland Pond is necessary to support safe, clean, and effective construction of a new outfall pipeline, which will be buried underneath the berms that create the pond.
The City evaluated several approaches for dewatering the pond, in consultation with Oregon Department of Fish and Wildlife. A gradual, months-long approach was selected as the most environmentally beneficial approach. In addition to supporting construction of the new outfall, dewatering the pond will result in other environmental benefits.
Foremost, dewatering will facilitate the installation of a new intake to the pond, with an ODFW-approved fish screen. Currently, the pondís intake is not screened and is fed by a small stream that does not always provide a reliable water source. The new intake will be properly screened and moved to Ashland Creek, where the City holds a water right for the pond. This action will ensure a long-term, reliable, and lawful source of water to the pond, and will exclude native fish from becoming trapped in the pond, such as threatened Coho salmon.
Additionally, temporarily dewatering the pond will eliminate many of invasive aquatic species that live in the pond. The pond is densely inhabited by invasive fish and amphibians, which compete with beneficial native aquatic species. The gradual drawdown and dewatering will eliminate many of these species, while the gradual approach will allow beneficial natives like turtles and salamanders time to move to nearby aquatic habitat.
Finally, dewatering the pond will enable restoration of areas of deep erosion and weak points in the pondís embankments. There are three specific locations within the pondís embankments that require restoration and strengthening, including the future intake along the Ashland Creek berm, the pondís outfall/drain in the Bear Creek berm, and the emergency spillway. Part of the restoration work will include bioengineering techniques to maintain the integrity of the pondís embankments, which involves the use of selected, hardy plant species with root systems that ďgripĒ soil in areas vulnerable to erosion.
Final construction of the outfall pipeline is planned to begin in summer of 2022. The outfall will be located approximately 100 feet downstream from where Ashland Creek flows into Bear Creek. The route of the pipeline will roughly parallel Ashland Creek after it leaves the WWTP and will then be routed underneath the existing access road and walking path leading to Ashland Pond. The pipeline will loop halfway around Ashland Pond in a clockwise direction, where it will discharge to Bear Creek at the same location as the pondís drainpipe. This route was selected, in part, for its minimal impact to sensitive habitat.
As the City proceeds with the design and permitting process, they will provide information to the public and coordinate with stakeholders. More information will be available at www.ashland.or.us/healthycreeks.
For more information on the project or to get added to an email list for project updates, please send an email to the City of Ashland Public Works Department firstname.lastname@example.org