MARBLETOWN – Unlike many nearby towns, Marbletown doesn't boast a pool. Instead, the town maintains a waterfront along the lower Esopus Creek in Tongore Park. That makes swimming in Marbletown uniquely sensitive to every decision made in the management of the Askokan Reservoir, because virtually every drop that flows by the man-made beach is released from that New York City-owned property. Too little water and the creek all but dries up. Too much and the current sweeps away sand and swimmers alike, making it too dangerous. Attempts to find the right flow have been rocky, with town officials closing the beach during flow levels that DEP engineers thought had been agreed upon as safe by those same personnel.

"The lifeguards are the sole determination of safety," explained Marbletown's town supervisor Michael Warren. They first test the current's speed by dropping a float in the water; if it passes through the designated swimming area in less than five minutes, then they dive in and make a judgment call. This July, it was determined that the conditions weren't safe for several days near the end of the month.

That's puzzling to Adam Bosch, DEP spokesman in this area, who lives in Marbletown. He said that the NYC Department of Environmental Protection, which oversees the releases, balances a number of factors including keeping the reservoir at an appropriate level, protecting the area from flooding, and preserving recreation spots like Tongore Park for use. The amount of water released by the DEP on the days the park was closed for swimming was less than what DEP and Marbletown officials agreed to, he said, and also less than what was flowing naturally earlier in the month, when swimming was allowed at the waterfront.

"This year we had thunderstorms every single night for a while, which dumped an incredible amount of water into the watershed," Bosch recalled. "The state called us to release water and the very first thing we thought about was the Marbletown waterfront."

After last year's releases eroded the sand and made it impossible to swim, DEP and the state Department of Environmental Conservation agreed that it was okay to slow down the flow, "so long as steady, measurable progress was made to get down to the objective." Several days of testing with the town lifeguards yielded a target of 140 million gallons daily, so when the reservoir was close to full, DEP officials decided to go under that, releasing 120 million gallons a day.

According to Warren's recollection, those tests last year were supposed to be the beginning of a nine-month test of flows, not an end result. To his mind, the problem has more to do with the DEP holding off releasing any water until the reservoir is full to the brim.

"I told them in June that the reservoir was full, and we couldn't hold camp with those big releases so why not pre-release in June?" Warren said.

He suggested that a daily release of about 45 million gallons over several weeks would have brought the levels down while also keeping the creek healthy. These so-called community releases are a cornerstone of what Marbletown and other municipalities which have joined together as the Coalition of Lower Esopus Communities would like to see in the reservoir's management plan.

That plan, the conditional seasonal storage objective (CSSO), calls for the reservoir to be kept at 90 percent capacity in the winter, and filled up again in the spring and summer. A reservoir that's too full runs the risk of causing flooding during heavy storm events, but if it's too low, there may not be enough water for the system's 9 million users — including a number of local communities.

"There's no scientific data to support keeping the reservoir that full," Warren said. "Ashokan has a lot of controls, but at 100 percent you have no control."

According to comments the supervisor submitted to the DEC, New York City has reduced its water usage by closing leaks in the system, and could maintain a void in the reservoir without endangering its users.

How that debate played out at Tongore Park last month is more puzzling. Bosch provided charts which showed that the natural flow of water down the creek was actually higher in early July than during the DEP releases towards the end of the month. The waterfront was only closed during the releases, however, not during the natural high flow. Moreover, the DEP spokesman said he went down to the park one day that it was closed for swimming to observe the conditions for himself, and found a number of swimmers enjoying the water.

"It was mostly young boys, age 10 to 15, and a 61-year-old woman," he said. "The woman commented that she appreciated how deep the water was because she was able to swim laps across the creek, something she usually isn't able to do."

Warren said that the answers aren't always simple.

"We need to study the effects of the releases on swimming," he commented. "In some cases, it doesn't seem to correlate between what is released and safety" at the waterfront.

For his part, Bosch thinks that the lifeguards should be using more accurate tools than a float on the water, or subjective testing.

"They measure surface velocity... we suggested they use the gauge to determine how much water is in the creek at a given time," Bosch added, pointing to state Department of Health regulations which define 3 feet per second as a safe standard. "We try not to use an arbitrary measure. When the state tells us to release water we have to get to the objective, but we also want to maintain swimming and other activities along the Esopus."

It appears that the DEP and town are having difficulty understanding each other. The several days of testing was enough to satisfy DEP officials, but the town supervisor thinks that should have been the beginning of a months-long process of study. A more extensive look might explain the apparent disconnect between the amount of water flowing down the creek and the evaluation of conditions performed by the town's lifeguards.