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Park sewage overflows Millions of gallons discharged into meadow near Yellowstone River By MICHAEL MILSTEIN Gazette Wyoming Bureau YELLOWSTONE NATIONAL PARK - National Park Service workers have begun discharging millions of gallons of treated sewage into a waterlogged meadow north of Fishing Bridge to prevent the catastrophic failure of a sewage treatment plant pond holding nearly 4 million gallons of similar wastewater. While the meadow extends about one mile to the shore of the Yellowstone River, the meadow held so much standing water even before the sewage discharges began that it's unclear whether any of the sewage has reached the river, officials said. Even if it has, the sewage has already completed a circuit through the national park's sewage treatment plant at Fishing Bridge and should mix with so much spring runoff that it should cause little environmental impact, officials said. "With the level of the river and the amount of runoff it's carrying, the effects of this thing should be pretty minimal," said Yellowstone Chief of Maintenance Tim Hudson. "This is not an environmental disaster. It isn't right, but it's not a disaster." Initial tests have shown no decline in water quality in the Yellowstone River below the meadow, Hudson said. While the treated sewage flowing into the meadow contains measurable amounts of fecal coliform bacteria, so does untreated river water.
State regulators expect to cite Yellowstone Park officials for violating water quality laws for the second time in as many years with the park's latest sewage spill, said Dennis Hemmer, director of the Wyoming Department of Environmental Quality. But he acknowledged that park workers had no choice but to siphon water out of a six-acre sewage pond that would otherwise have overflowed and failed, releasing all of its 4 million gallons at once, inundating adjacent wetlands and rendering the entire Fishing Bridge treatment plant inoperable. Without the plant to process sewage, park officials would have had to close all visitor facilities in Yellowstone Park's Lake, Fishing Bridge and Bridge Bay developed areas. Park officials notified the state before they began siphoning water from the pond into the meadow starting Tuesday night at the rate of about 400 gallons per minute, or more than 500,000 gallons per day. Hudson expects to continue the siphoning for at least a week and possibly more, releasing more a total of 3 million gallons into the meadow. "It's not our preferred option but right now it's the only option, and I don't think you're going to see much long-term damage," Hemmer said. "The only option was what they did." Last year the DEQ last year issued Yellowstone a notice of violation for four sewage spills, two at the Lake developed area and two others at Old Faithful. Also last year the DEQ authorized park crews to dispose of treated sewage from the sewage treatment plant at Fishing Bridge by using sprinklers to spray it over the same meadow where they are now releasing it. At the time, the meadow was dry. Since it is now full of water, it is considered a wetland and discharging sewage into it is a violation of water quality laws. Sewage from facilities at the Lake, Bridge Bay and Fishing Bridge areas all flows to the treatment plant just north of Fishing Bridge, where it proceeds through a series of tanks and settling ponds where bacteria break down solid matter. From there it enters one of two initial percolation ponds where the treated sewage either percolates into the ground or evaporates. Remaining wastewater continues from those ponds into a third and final percolation pond, which has no outlet. Construction of the Fishing Bridge sewage treatment plant began in 1973 with the assumption that all the treated sewage would percolate or evaporate out of the ponds and leave them dry each fall, when workers could plow up the bottom of the ponds to keep the ground absorbent. But wet weather in recent years and an increasing flow into the plant has often kept the ponds from drying out, leaving workers unable to plow up the layers of matter that otherwise form at the bottom of the ponds. Those unbroken layers have consequently slowed percolation of the treated sewage into the ground. Compounding the problem, thousands of gallons of ground water are apparently leaking into lines that carry sewage to the treatment plant, increasing the load on the plant even when its ponds cannot handle much more. Such ground water infiltration has been especially extreme during this year's wet spring. As of the end of this week, for instance, the National Park Service water treatment plant that serves the Fishing Bridge area was producing about 225,000 gallons of potable water for nearby hotels, campgrounds and other facilities each day. But about 430,000 gallons of sewage was entering the treatment plant per day. Most of the difference - more than 200,000 gallons - results from ground water seeping into sewage lines. "We can't get the ponds dry because of the weather - and the infiltration increases the amount of water coming in," said Bruce Sefton, head of maintenance for Yellowstone's Lake and Fishing Bridge area. "We have nowhere for it to go." Park workers realized in recent weeks that treated sewage was rising inexorably in the percolation ponds. By Tuesday, the contents of the third and final pond were lapping at the top of the earthen dike containing the pond. Park workers feared that if the pond overflowed, it would wash out the dike, breaching the entire impoundment. "Pond three was so full, we thought the dike would fail and we'd lose the whole pond," Hudson said. After notifying the state, park workers at about 6 p.m. on Tuesday set up two tubes to siphon water off the top of the pond, over the dike, through a barbed-wire fence designed to keep grizzly bears out of the sewage plant and into the adjacent meadow. The treated sewage flowing into the meadow has a slight green tinge from algae feeding off the nutrients it carries but otherwise looks no different from nearby lake or river water. Park crews have siphoned water out of the pond and into the meadow during at least two previous years with the authorization of the state, Hudson said. But after last year's sewage spills, state regulators demanded corrective action and they plan to do so again. "We realize they faced a critical situation and the priority is to make sure they don't breach the pond," Hemmer said. "But our focus also has to be on finding a long-term solution because we can't have this happening year after year." Park officials plan to begin asking visitors and park employees to voluntarily conserve water to reduce the pressure on the treatment plant at Fishing Bridge. They also plan to hire an engineering firm that next week will begin searching for the main sources of ground water infiltrating the sewage lines. "The Park Service seems to be doing their job - they're trying to make the best of a bad situation," said Michael Scott of the Greater Yellowstone Coalition. "Now it's up to Congress to step up to the plate and provide consistent funding for a definite schedule to get these sewage problems corrected."
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