Park gets 100% payback 7 months after installation

The giant forest area of Sequoia National Park annually attracts more than 1.5 million visitors from May through November.

Several hundred thousand people stay in the hotel and in the rustic cabins each year. But Imhoff Wastewater Treatment Plant at Giant Forest, built in the 1930s, had been operating under a temporary discharge permit since 1978.

Deemed substandard, the aging plant’s level of treatment was best described as “partial primary” only. Solids were skimmed off, and the remaining effluent was heavily chlorinated and sprayed over a steep mountainside below the Giant Forest.

The temporary discharge permit had been issued because Giant Forest was scheduled to close in 1990, and a new treatment plant as well as hotel, dining and recreational facilities were to be built at Wuksachi Village, about six miles away.

The new facility would enable the Park Service to return the Giant Forest, with its thousand-year-old trees, to its natural state and avoid the risk to the Sequoia’s root systems that had been posed by buildings and development at the site.

But in 1988, delays in funding for the new treatment plant and tourist facilities prompted the California Regional Water Control Board (CRWCB) to grant another temporary discharge permit, this time for five years. By 1993, the new facilities were underway, but not completed, when the temporary discharge permit expired. In November 1993, the CRWCB notified Giant Forest of its intention to close the entire operation unless the park could submit an operations plan detailing its ability to achieve full compliance with all applicable wastewater treatment standards.

An interim agreement was developed that would allow continued operations for a limited time. Among the restrictions was a phased-in reduction in water flow.

Water-conserving shower heads, new faucets, water-saving dish machines and 1.6-gallons per flush (gpf) pressure assist systems were installed in the park’s 250 water closets by May 1994. At the same time, the park launched a massive information campaign to encourage employees and visitors to conserve water.

Initially, the National Park Service and the CRWCB estimated a water savings of 18,000 gpd, but neither agency thought these reductions, though significant, would be enough to keep the park fully open.

But, during the five busiest months in 1994, from May to September, water flow was reduced by nearly 53 percent, or an average of 32,000 gpd.

Giant Forest selected water closets equipped with the Flushmate pressure system from Sloan Valve, Franklin Park, Ill. The valves and other water conserving equipment enabled Giant Forest to stay well below the maximum daily water flow mandated by the state.

In 1993, more than 11 million gallons of water were used, compared to 5.3 million gallons in 1994.

The changes were cost effective, too. Officials have reported a 100 percent payback on the water-saving program less than seven months after installation.