More North Shore streams under stress
Feb 27, 2018 06:27AM
By John Myers of The Duluth News Tribune on February 26, 2018
Six more of the once-pristine streams that flow into Lake Superior along the near North Shore are officially impaired due to increased development, more erosion and too much silt in the water.
That was the message Monday from two reports released by the Minnesota Pollution Control Agency on the southwestern segment of the North Shore, from Duluth to Beaver Bay.
All six of the streams have official Clean Water Act "impairments'' for too much silt, or turbidity, in the water on too many instances, including the Beaver River, Big Sucker Creek, French River, Talmadge River, Little Knife River and Skunk Creek.
Skunk Creek, which flows through Two Harbors, also failed tests for E. coli bacteria, with frequent readings above safe standards. Brian Fredrickson, PCA water projects manager for the region, said the bacteria could be coming from nuisance animals, pets and leaky sanitary sewer lines.
The Beaver and Talmadge rivers also are impaired because they have far fewer fish than they should support. (The Knife River has been listed as impaired since 2011 for turbidity with efforts already underway to solve the problems. Streams within Duluth proper will be included in a PCA report later this year.)
The main issue for North Shore streams is the unstable clay soil left behind by glaciers 11,000 years ago. Once exposed after any kind of development, the clay becomes extremely unstable. The first round of logging a century or more ago set the stage for erosion problems, followed by roads, cabin and home sites and even recreational activities, all of which can spur vast amounts of clay to flow into the streams.
Nearly all of the North Shore rivers start in relatively undeveloped, forested areas, and they all start with good water quality. The problem comes as they get closer to Lake Superior, and wind through developed areas, where there are more roads, parking lots, buildings and other impervious surfaces that spur rapid runoff of rain and snowmelt, which makes the erosion problem even worse along the relatively steep slopes of North Shore hills.
April and May are often the worst months for the most sediment in streams with the rush of snowmelt towing along clay particles. That problem has been made worse by the change in the forest makeup over the past century — due to logging and fires — from mostly pines and cedars to birch, aspen and other deciduous species.
"The issue becomes more pronounced where we have more deciduous forest and fewer conifers,'' Fredrickson noted. Conifer trees shade more snow and slow the melting. The North Shore Forest Collaborative is working to restore pines and cedars where old and dying birch now are the dominant trees along the Lake Superior hills.
Some of the streams in the zone are doing well, including the Gooseberry, Split Rock and Encampment rivers and Silver Creek.
In addition to identifying problems facing the streams, the PCA reports also identify solutions — things like stabilizing soils near the streams, minimizing hard surfaces that spur rapid runoff and establishing conservation easements to keep undeveloped land along the rivers from being built on in the future.
"That's going to be the next challenge, to find more specific sites and then get the funding needed'' for projects to reduce runoff, Fredrickson said. "We humans tend to smooth out all the places that can hold water to slow it down (before it gets to the stream) and we need to preserve as many of those places as possible."
Restoration efforts already have worked in some areas. Farther up the North Shore, the Poplar River in Cook County last year shed its impairment for turbidity after years of efforts by government agencies, conservation groups and local landowners. The river had been the victim of large sloughs of hillside eroding into the otherwise clear North Shore trout stream, especially in the area of the Lutsen ski hill. Efforts to reduce erosion and stabilize the streambanks have improved water clarity enough to remove the impairment.
The latest PCA reports open for public comment are called the Total Maximum Daily Loads study and the Watershed Restoration and Protection Strategies report. After considering public comments, the agency will revise the draft reports and submit them to the U.S. Environmental Protection Agency for approval.
The draft reports are online at www.pca.state.mn.us/water/watersheds/lake-superior-south or can be obtained at the PCA's Duluth office, 525 Lake Ave. S. Comments will be accepted through March 28 to [email protected] or by mail to Brian Fredrickson, MPCA, 525 Lake Ave. S., Suite 400, Duluth, MN 55802.