wash of gravel down Mill Creek that tore up a piece of the South
Skagit Highway and buried fish habitat last month was only partially
caused by logging, according to a state hydrologist.
The creek, which flows into the Skagit River from the south near
Birdsview, flooded on Feb. 22, a day of heavy rains that saw the
Skagit and other Western Washington rivers rise. Gravel flowing down
the creek choked the channel under the South Skagit Highway bridge,
forcing the creek out of its bed, where it chewed a hole more than
half the width of the highway through the pavement. The gravel also
buried spawning areas used by salmon and trout.
Some owners of
neighboring property initially blamed logging for the slides. But
Jeff Grizzel, a forest hydrologist with the state Department of
Natural Resources, said most of the gravel apparently came from
landslides on unlogged land owned by the U.S. Forest Service.
After surveying the area by air and by foot, Grizzel said 15 to
20 landslides on Forest Service land were triggered by storms Jan.
8-9. About six slides were on logged land and were related to that
logging, he estimated.
The slides released gravel and large amounts of wood that tore at
the sides of the stream, destabilizing them and releasing even more
gravel into the channel, he said.
Most of the gravel that ended up at the South Skagit Highway
bridge had been washed partway down the channel in January, he said.
The Feb. 22 storm pushed the sediment the rest of the way.
Although most of the
problem was not due to logging, Grizzel noted that most of
the logging done in the area would not be allowed under rules
adopted last July. The slopes in that area are too steep to be
harvested under current standards, he said.
In addition, the logging road in the area, where some of the
slides started, must be improved by 2015 under another new set of
Grizzel said he couldn’t determine which company had done the
logging or owned the land, thanks to a complex and often-changing
land ownership pattern on the slopes.