A treatment system meant to keep the Boise and Snake rivers clean is back on track after the city of Middleton withdrew its appeal of a conditional use permit for the so-called Dixie Drain Phosphorous Offset Project.
Located near Parma, the Dixie Drain is intended to remove phosphorus from the Boise River before its confluence with the Snake River by diverting water into a three-phase treatment facility. Water flowing out of the drain would help Boise and surrounding communities better meet Clean Water Act standards.
Untreated, the Boise River contains about 4,000 micrograms of phosphorous per liter. At the current treatment level, it contains about 350 micrograms of phosphorous per liter. The Dixie Drain is expected to bring the river closer to Environmental Protection Agency compliance: 70 micrograms of phosphorous per liter.
The cities of Greenleaf and Middleton both appealed Boise's application for a conditional use permit, alleging that the project would impact their ability to grow, and raising concerns that excess downstream phosphorous would lead to tighter restrictions from the EPA.
They also took aim at the project's cost, which was initially expected to be $12 million.
The city of Boise agreed to assist both cities with upgrades to their wastewater treatment plants in an agreement to drop appeals against the project. Greenleaf gave its OK to the Dixie Drain in late January, but Middleton officials waited until Feb. 13 to sign off on the agreement. A final cost figure, including the Greenleaf and Middleton upgrades, has yet to be released.
"Residents of both cities will benefit from the agreement. Middleton appreciates Boise's effort to recognize the impact of Boise's permits and projects on water quality near Middleton," wrote Middleton Mayor Darin Taylor in a press release.
Now that Middleton has withdrawn its appeal, the Dixie Drain project is set to move forward with construction in the early spring.