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How reservoir enlargement benefits the Siletz River

Replacing a dam and enlarging a reservoir isn’t typically the type of water project that is associated with benefiting rivers, but Newport’s Big Creek Dams Project is different.

The City of Newport gets its water supply from the Siletz River, but currently the water storage capacity in the Big Creek Reservoirs doesn’t meet summer demand. “We turn on the intake station on the Siletz River each year from May through October, or at least until we start getting rain in the fall,” said Tim Gross, Newport Public Works Director. “During that time up to 10 percent of the water flowing by that intake from the Siletz River is pulled into Newport’s reservoirs for use by residents and businesses.”

This has sometimes been a source of conflict, with some concerned about water temperature and fish habitat in the river because less water is available during warm summer months. The Big Creek Dams Project will change all this for the better.

It’s hard to imagine what life would be like without a reliable water supply—but Newport is at risk today because the dams on the reservoirs that hold the City’s water supply may not withstand even a minor earthquake. The risk to life-safety and the city’s economy is so great that the State Dam Safety Engineer has listed Newport’s Big Creek Dams as two of the three most critical, high-hazard dams in Oregon. Design of the Big Creek Dams Project is underway. The project will replace the two dams on the Big Creek Reservoirs to make them resilient to earthquakes.

We plan to enlarge the reservoir to hold another 1,000 acre-feet (about 325 million gallons) of water. If we can store more water in the warm summer months, we can pull less water from the Siletz River.”

To date Newport has invested $2 million toward developing a solution that will save Newport’s water supply, make it earthquake resilient and allow the City to store more water for future population growth and for use during drought.

Sustaining the environment is a critical component of the project. Newport can accomplish its water supply goals while enhancing the natural habitat and lessening its reliance on already stressed water resources. The water intake process on the Siletz River has been a source of conflict in the past. As the water level decreases in summer months, concerns about water temperature and fish habitat in the river increase. The Big Creek Dams Project will change all this for the better. How is this possible? With more water in storage, Newport will have more flexibility in how and when it supplies water to the city. That means the city can take less water through its Siletz river intake during times when the river is stressed by high temperatures and lower flow.

“We plan to enlarge the reservoir to hold another 1,000 acre-feet (about 325 million gallons) of water. If we can store more water in the warm summer months, we can pull less water from the Siletz River,” said Gross. “Doing this will mean that the temperature in the Siletz will be more consistent and colder, improving fish habitat. The dam would be raised about five feet to enlarge the reservoir and increase storage capacity.”

These improvements, along with the relationships Newport is building during project development, are part of the City’s commitment to be a responsible community partner and to doing the right thing. This project will provide a secure water supply for Newport water customers while benefiting the region’s environment.