Mussels prompt concern about city?s water flow

Hillsboro?s city administrator said Monday the city is at a ?high concern? level following a decrease in raw water flow last week from Marion Reservoir caused by the presence of zebra mussels in the intake system.

?We?re not at the ?emergency? level,? Larry Paine said, citing efforts by city personnel to address the problem over the weekend.

An ?emergency? level would prompt the city to enact mandatory water-conservation practices that essentially would prohibit the use of city-treated water for outdoor uses such as garden and landscape maintenence.

The electronic monitoring system at the reservoir pump station indicated a ?low flow? alert Thursday that water intake had slowed to 300 gallons per minute?just enough to keep up with the amount required by clients in Hillsboro and Peabody at the time.

Paine said city workers became concerned after noticing that the baskets installed at the pump station to keep mussels from entering the system were empty, but the system was still registering a low flow.

?With these (baskets) empty and the flow restrictions, the alarm goes off in everybody?s mind that says, OK, the pipe from the inlet to the end of the pump house is somehow obstructed,? Paine said.

The water flow increased to 500 gallons per minute by Monday.

?We?ve ramped up to the demand we were using over the weekend,? Paine said. ?At the same time, we?re at full water-tower capacity. It?s something we do in the summer to make sure we keep those things topped off.?

The city?s two water towers hold sufficient water for about four days of normal use, he added.

Paine said a plan is being developed, in cooperation with Marion, which uses the same pump station, to flush out the meddling mussels by adding a release valve at the end of a 12-inch line.

When the valve is opened, the weight of the water in the dam should force water through the line at an estimated 2,000 gallons per minute.

?That creates enough velocity that the zebra mussels won?t stick to the pipe,? Paine said. ?We think the water pressure at the head of the dam would create that.?

Paine estimated the flushing effort wouldn?t begin until Tues?day or Wednesday of this week.

?We still have some issues around finding a contractor who will get out there and dig this thing,? he said Monday. ?We?re dealing with some slope issues (at the dam). Where we dig and how we dig is going to be important.?

With four days of water stored in the city towers. Paine said he isn?t concerned about the local supply, even with temperatures forecast in the low 100s for the entire week.

?If it doesn?t flush well, and we?re not able to keep pumping to a higher level, then we?re going to have to worry about it,? he said.

Paine said the city will be monitoring the situation daily. If the city is forced to enact emergency water-conservation practices, residental and commercial customers will be notified by hand-delivered notices.

?It?s going to be important that, from our side, we try to do what we can to keep (the water supply) going so people can keep their gardens and their landscape,? Paine said. ?But if it gets to the point that we can?t do that, taking care of one another is more important than that.?

If water restrictions are enacted, daily updates will be made available online at cityofhillsboro.net and hillsborofreepress.com as well as the city?s Facebook page.

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