High dam releases put extra load on sanitary sewer, city staff

Talk about it

Local officials say the continued combined releases of 1,800 cubic feet per second will continue to place strains on the city’s sanitary and storm sewer systems. It is also requiring a higher level of management.

The U.S. Army Corps of Engineers released a water release plan Wednesday that includes 1,800 cfs releases through mid-to-late October. In previous years, releases of that level commonly ended no later than June.

“It means we’ll be under heavy stress for a couple more months,” said Reed Schwartzkopf, city engineer. “And it means a lot of preparation for next year.”

Schwartzkopf said the sanitary sewer system is handling between 6 and 6.5 million gallons per day. This level does not require special intervention under normal conditions.

During previous high water events, groundwater infiltration into the sanitary sewer pipes have increased flows through the system from its normal use of about 2 million gallons per day. The worst occurred in spring 2009 when several lift stations pumped sewage directly to the river because of high system loads.

“Now if there is a power outage or other failure the time to react is a problem,” he said. “We have to watch the system constantly for problems.”

If emergency generators are not brought online quickly enough, backups into homes could occur, Schwartzkopf said.

Managing the sewer system and the dam releases has been an all-summer task, said Jerry Bergquist, Stutsman County emergency manager.

“It’s been a juggling act,” he said. “We have to be watching the weather all the time. If there is a rainstorm without a reduction to the releases from the dams, the flows through town can cause damage.”

The 1,800 cfs from the two dams places the James River in Jamestown at its flood stage of 12 feet. Additional local runoff in Jamestown could cause the river to rise above flood stage if rain occurred while the releases are maintained.

The high water levels behind the dams have prompted a higher level of routine inspections of the dams.

“This is by far the most water we’ve had at this time of year,” said Bob Martin, dam manager for the corps. “We do routine seven-day per week inspections when we have these high water situations. The dams are performing as intended.”

City officials are also trying to determine if increases to the flows could be accommodated in Jamestown if it is necessary. Tim Temeyer, hydraulic engineer for the corps, said releases of 2,100 to 2,200 cfs may be possible with the river staying within its banks.

“We’re assessing that to see if tweaking the flows can be accommodated,” Schwartzkopf said. “We need to see what the effects to Jamestown would be if it is necessary to go up above the 1,800 cfs. This is a serious event for us and the downstream sites in South Dakota.”

Bergquist said discussions with the corps have not included releases above 2,100 cfs at this time.

And while officials continue to deal with this year’s water, they express concern for next year.

“This is turning into a long year,” Schwartzkopf said. “None of the options we have are all that palatable.”

Sun reporter Keith Norman can be reached at (701) 952-8452 or by e-mail at knorman@jamestownsun.com

Tags: local news, news, jamestown, water, sewer, pipestem