HomeMy WebLinkAbout20233466.tiff U %0U\R 100 N 6th Street, Suite 410B 612 . 230. 0172
Minneapolis, MN 55403 www. us-solar. com
USS AUBURN SOLAR LLC SOIL REPORT
Please refer to Attachment 2 of the USS Auburn Solar LLC Preliminary Drainage Report for the Soil Report.
Drainage Report I USS Auburn Solar LLC April 21, 2023
creek flows from south to northeast to the east of the site. The reservoir and adjacent creeks are
not anticipated to impact the site .
onsite Soils
The soils for this project site are predominantly classified as hydrologic soil group (HSG) A
(Attachment 2) . The soil types found in the project site area are Vona Loamy Sand, 0 to 3
percent slopes . For the sake of this project, all soils onsite have been modeled as HSG type A.
This soil information is based on the Natural Resources Conservation Service (NRCS) National
Cooperative Soil Survey.
Timing/ Phasing Schedule
In the initial and interim stages, the contractor shall install silt fence, vehicle traction control
and concrete washout at the entrance, and a stabilized staging area. In the final stage of
construction, seeding, mulching, and surface roughing shall be done in all disturbed areas, and
erosion control blankets shall be installed on all slopes greater than 4 : 1 . The contractor shall
also remove the vehicle traction control, concrete washout, stabilized staging area, erosion
control blanket, and silt fence in the final stages of construction.
BMP Installation, Inspection , and Removal
BMPs will be installed prior to project construction, except for the BMPs in the final stage.
BMPs will be inspected weekly and as required by the County through project completion by the
contractor. BMPs will be maintained and remain in place at least until construction is finished
and the site is vegetated. Once all exposed areas have been covered, the BMPs may be removed.
Since the project does not include any other disturbance, no additional site stabilization is
necessary and/or warranted.
Permanent Stabilization
The project will be seeded with the Weld County's upland area seed mix to establish permanent
stabilization after construction activity has ceased. Reference the Temporary and Permanent
Seeding Table on page EC-2 of Chapter 7: Construction BMPs in the USDCM Manual, Volume 3 .
As per the USDCM Manual, permanent seeding involves the loosening of soil, applying topsoil,
drill seeding the disturbed areas to a depth not less than 1/4 inch and not to more than 3/4 inch,
and crimping the seeded areas in straw mulch at a rate of 2 tons per acres to provide immediate
erosion protection.
Summary
The proposed site will be designed to maintain its existing drainage patterns . Due to the limited
amount of impervious surface proposed and the proposed conversion of the site from row crops
to the vegetated cover under the panels a decrease in runoff rates is expected for the proposed
conditions when compared to existing conditions . Water quality treatment will be provided by
the disconnected impervious and the proposed vegetation below the panels .
Based on the landcover conversion and the addition of the low impact design the site design will
adequately protect public health, safety, and general welfare and will have no adverse impacts
on public right-of-way or offsite properties .
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