Ecologists welcome snow — A dry December had challenged salmon and steelhead populations
January 20, 2012 · 11:07 AM
Avoiding snow for this long may have been a relief for Kitsap County residents, but posed a concern for river and stream ecologists monitoring salmon and steelhead populations.
December was a dry month for Kitsap County, said Johnny Burg, meteorologist for the National Weather Service in Seattle.
The average precipitation for December is usually around 10 inches, Burg said. This year Bremerton had only 3.43 inches of precipitation in December – almost 7 inches below average.
Seattle and Olympia had their driest winter season so far on record, Burg said.
“It’s kind of unusual that it held off until now,” Burg said. “But it looks like we’re getting our money’s worth in one shot with this week’s snow.”
“Fish species depend on snow,” said Douglas Zimmer, spokesman for the Washington Department of Fish and Wildlife. “You need a certain amount of water flowing to protect fish species.”
Salmon eggs are already down, but steelhead are starting to spawn, Zimmer said.
Higher water levels from precipitation and snow run-off allow these fish to get up the river, past blockages and log jams, Zimmer explained. The further they can get upstream into the tributaries, the better chances offspring will survive.
Snow fall also helps cover and protect eggs from avian predators, and higher water volume triggers a “biological restlessness” that gets new spawners moving.
Fish moving upstream and depositing nutrients and salt keep those areas from becoming sterile. Predators also eat some spawners and redeposit those nutrients in the forests higher up.
“It’s a complex chain that starts with snow falling and ends with a tree in the upper part of the Olympic Peninsula getting the nutrients it needs,” Zimmer said.
Water supply systems also depend on snowfall, Burg explained. When the snow from mountains runs off into rivers and reservoirs, it replenishes the water supply.
According to the Jan. 1 National Weather Service report, mountains were at 80 percent of their expected snowfall levels this year.
“Continued low snow fall would impact reservoir water supply, making it come up short for the summer months,” Burg said. “That would lead to water restrictions for residents.”
The City of Bremerton does not depend directly on snow pack, but water systems do rely on precipitation and some snow which melts and supplements the reservoir, said Kathleen Cahall, the city’s water resource manager.
“The fall and winter levels are important for our water supply,” Cahall said.
Cahall said that current levels are only slightly short and the winter storms will certainly help catch the city up for the year.