Wetland Restoration: What is being done now?
The Minnesota Department of Natural Resources received a grant of $170,000.00 to improve
wetland habitat for plants and animals at Grassy Point from the Great Lakes National Program
office of the Environmental Protection Agency. Along with matching funds from state and local
sources, several projects have recently been completed or are underway.
During the winter of 1994/1995, the DNR contracted with LHB Architects and Engineers and with
American Engineering and Testing to assess where the sawmill waste occurred, how deep the
material went in the wetland, and if there were chemical contaminants from human sources in the
areas of waste wood.
One hundred twelve borings were completed on a 200-foot grid to a depth of 10 feet below the
existing surface or 2 feet beyond existing wood waste. Four sediment samples were collected from
the base of the wood waste at separate boring locations. The samples were sent to Legend Technical
Services for analyses.
The results of the metals
analyses show that some metals are present in the samples in low
concentrations. All concentrations, however, were below the "No Effect Level" defined by the
Ontario Ministry of Natural Resources.
Analyses for PAHs show that PAHs were present in all of the samples, however, the total PAHs for
each sample was less than one part per million. Total PAHs ranged from 0.13 mg/kg to 0.96 mg/kg.
All samples were below the Ontario Sediment Quality Guidelines "lowest biological effect" level of
2.0 mg/kg.
Samples of wood were collected from two borings for chemical analyses. There is some reason to
believe that PAHs and PCBs may be found in higher concentrations in woody debris buried in
contaminated sediments than in the surrounding sediments. The samples were sent to Legend
Technical Services for PCB and PAH analyses. PCBs were not detected above the Method
Detection Limit in the samples. PAHs were detected in low concentrations; the total concentrations
for the two samples were 0.15 and 0.09 mg/kg. There was no evidence that the wood waste was
drawing in any organic contaminants and concentrating them.
The subsurface exploration at Grassy Point found that the wood waste was not uniform in size,
varying from sawdust and wood chips to boards and logs. It also documented that there were certain
areas that contain wetlands with no wood waste present. The northeast and north parts of the site
consist mostly of peat. In the remainder of the area, wetland deposits are intermixed with fill that
contains boards, sawdust and uncut wood. The wood waste varies in thickness from 2.0 to greater
than 16.5 feet. In various locations, the wood waste is overlaid by a peat mat currently supporting
vegetation. The investigators concluded that the wood waste was limited to the central and eastern
portions of the site. Based on the pattern of lateral extent, it appears that the wood was placed in
areas next to and within the old Keene Creek channel after the creek was diverted to the slip next to
Hallet Dock 7.
Based on the findings of the subsurface exploration and chemical analyses, preliminary restoration
design plans were developed.
Consultation with project partners and resource managers refined the
plan to include two main components. First was a channel through the wood waste that would
connect the main channel of Keene Creek (which was recently restored to its historic location) with
the main channel of the St. Louis River. Second was one to two ponds connected to either the main
channel or the excavated, secondary channel. All excavations were to have a maximum depth of 6
feet and gently sloping sides. The deepest portions of the excavated areas should remain clear of
emergent vegetation due to low light penetration in the dark waters of the St. Louis River and
should provide substantial improvements for waterbird habitat, fish habitat, and the movement of
fish through the area and into Keene Creek.
During the winter of 1995/1996, 11,000 cubic yards of wood waste were removed from the site,
creating the secondary channel, the west pond and half of the south pond.
Video
Using funding from a grant from the Coastal Services Center, NOAA, the DNR contracted with the Arrowhead Regional Development Commission and Whitewater Assoc. to gather baseline ecological assessment data. These data will be part of the monitoring program used to assess the effectiveness of the wetland restoration activities at Grassy Point. The monitoring report from Whitewater Associates should be available in October 1996.
The Section of Fisheries, MN DNR, completed a baseline fisheries
assessment at Grassy Point in the September 1996. Results indicate that the newly excavated areas
and
the open water areas are used by a variety of fish species.
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