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Dte – Environmental Division
Michigan ● Taggart Compressor Station ● Six Lakes ● Active Gas Compressor Station
Wetland soil impacted by improper disposal practices involving heavy metal (mercury).
Objective – remove mercury-impacted soil within a regulated wetland, contiguous to a lake.
Clearing and grubbing of trees, stumps, roots and other vegetation to the anticipated depth
of the remedial activities ● Trees downed in designated wetland areas were stockpiled and
redistributed across the wetland at completion of the work ● Per the wetland permit, stumps
from trees removed only for access purposes (and not in the remedial area) remained in the
ground to promote reforestation.
Excavation, stabilization, transport, disposal of 1700 CY of mercury-affected,shallow wet soil
from an approximate 0.8 acre area, of which 0.75 acres was defined as wetland.
ERG surveyed the layout of the planned excavation work limits for 0.5 – 2.5 foot excavation
depths ● Survey stakes were set to delineate each post-excavation soil verification sampling
location ● Pre-excavation elevations were set in the work area on a 25 foot grid ● 1,250 feet
of silt fence was installed in accordance with Montcalm County’s Soil Erosion Permit.
The Wetland Restoration Plan was completed, which included installing eight (8) rip-rap check
dams ● Installing 200 linear feet of silt fence at each check dam ● Constructing seven (7) check
dams with logs salvaged from clearing activities ● Placing excess downed trees within the
restoration area ● Placing 1,055 feet of re-vegetation mat along the edge of the excavation
area in accordance with the Soil Erosion and Sedimentation Control Permit ● Re-seeding and
planting wetland trees ● Grading site to match pre-excavation 25-foot grid elevations.
ERG documented reconstruction of the wetland with a final as-built survey, which included
coordinates along the perimeter of the graded wetland restoration area, excavation boundaries,
excavation bottom elevations, center of each check rock dam and each log check dam, and
soil verification sampling locations.