Yosemite officials are seeking public comment on a plan to overhaul the Wawona Wastewater Treatment System that serves the Wawona Campground as well as the Wawona Hotel/NPS

Yosemite National Park officials are proposing an overhaul of the Wawona Wastewater Treatment System, which suffers from an over-taxed and antiquated system for handling human wastes from the southwestern end of the park.

While the park has a few wastewater treatment plant needs, the highest priority has been for the facilities in the Wawona area of the park. More than 1.3 million visitors tour the Mariposa Grove of Giant Sequoia trees each year, stay in the historic Big Trees Lodge (aka Wawona Hotel), or camp out under the trees. The campground accommodates 582 per night, all relying on a wastewater system up to 60 years old.

Since the system is very close to the South Fork of the Merced Wild and Scenic River, there is a “potential for failure and water contamination, if not completed,” park staff have said.

Proposed repairs call for three new lift stations in the Wawona Campground and replacing six saturated and failing leach fields with a 1.6-mile pipeline to the main Wawona system.

Under the park's preferred alternative, the upgrade would also improve the existing spray effluent disposal system and construct sub-surface effluent disposal trenches at the Big Trees Lodge Golf Course (aka Wawona Golf Course), and eventually replace the vault toilet at the South Fork Picnic Area with a flush toilet restroom (pending funding availability).

As Traveler  reported earlier this year, the Wawona Treatment Plant itself is critical to visitor services. In 2008 there were two large spills due to broken spray field piping, and discharge exceeded the daily permitted flow that summer 81 times. The plant also is undersized to meet the growing demand, so the waste is currently trucked twice a day to the El Portal Plant, a 90-mile round trip, during the summer until the system is repaired.

While the environmental assessment did not cite a cost for this project, the cost of upgrading the wastewater plant itself has been estimated at $24,479,000, and the work in the campground at $3,971,000.

The public can comment on the proposal through December 9. You can read the entire proposal and comment online. You may also mail comments (post-marked by December 9, 2018) to:

Superintendent, Yosemite National Park

Attn: Wawona Wastewater System EA

P.O. Box 577

Yosemite National Park, CA 95389

This rehabilitation project implements actions prescribed in the Merced Wild and Scenic River Comprehensive Management Plan, according to a park release. Construction for the project is planned to begin in late-summer 2019.