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Snowpack improves at watershed

After a marked lack of snowfall in the early part of the winter, snowpack in The Dalles watershed was looking much better at the end of February and is likely to have improved from there during March.

“I think we’re getting some [snow] now,” said Dave Anderson, The Dalles public works director. “We got some yesterday and today the snow is falling and it’s projected through the weekend.”

Snowpack had climbed to 70 percent of average for water content, Anderson said.

“That’s below normal, but it’s not the lowest we’ve ever seen,” Anderson said.

The National Oceanic and Atmospheric Administration estimated conditions south of The Dalles from October through March 24 had yielded snowpack at 80 percent of normal.

The city has been doing snowpack measurements since 1983 and five years during that period have had lower water content at the February measurement. The lowest was in 2005, when water content was less than half of what is was this February.

“The good news is, we got through 2005,” Anderson said.

The city will take its final snowpack measurements of the season on Monday, March 31

“That will be the one that tells us more,” he said.

February’s heavy rains produced some significant runoff, and quite a lot of silt in the water, a consequence of loss of ground cover burned during last year’s Government Flats Fire Complex.

Dirt in the water is measured by a turbidity rating that the city has tracked for the past 10 years. Until this year, the highest rating was 70.

“This last February, when we had the rain-on-snow event, it was over 1,700,” Anderson said. “It was pretty thick, but the plant was able to handle it. There was no unsafe water sent into the system, no dirty water got past.”

Fortunately, the worst turbidity passed quickly, but it held in the 200 to 300 range during the event. And there has been no evidence of landslides damming up the creek as a result of the destabilized landscape.

“We are certainly seeing an adverse impact to water quality as a result of the fire,” Anderson said.

The city is continuing its rehabilitation effort in the burned area. It seeded the area with grass last year and plans tree planting and salvage logging this spring and summer as part of its continuing efforts to rehabilitate and stabilize the burned area, he said.

“So far, we’ve only had one really dirty water event and we’re kind of beyond the conditions where that’s very likely for this year,” Anderson said. But that doesn’t mean the watershed is out of the woods. “It was about 20 years before the area fully recovered from the [School Marm] fire that occurred in 1967.”

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