The proposed project is in the Southeast 1/4 of Section 20, Township 21 North, Range 14 East, in Owasso, Tulsa County, Oklahoma. The project site can be found on the Collinsville, Oklahoma 7.5 Minute USGS Quadrangle map at North Latitude 36.27889 and West Longitude 95.83644 Decimal Degrees.
Purpose: The basic purpose of this work is to stabilize the stream channel. The project is not a water dependent activity.
The overall purpose of this work is to realign the channel back into the drainage easement and to stabilize the eroded stream channel and streambank below the ordinary high water mark of the unnamed tributary of Elm Creek. The stream channel is currently threatening private property and utility line infrastructure within the project area.
Table of Impacts:
Original Proposal
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Number or Location
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Impact Activity
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Type of Water
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Type of Fill Material
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Qty of Material cys below OHWM
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Footprint
(ac and/or lf)
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Sta. 9+71 to 20+00
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Bank stabilization
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Stream
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Articulated Block Revetment System (ABRS), Capstone Block, and associated materials*
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14,293 sq ft
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1,029 lf
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Sta. 20.00 to 30+32
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Placement of Fill Material
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Stream
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Earthen Materials
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7,925 cys
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1,165 lf
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cubic yards (cys), ordinary high water mark (OHWM), acre (ac), linear feet (lf), square feet (sq ft)
* associated materials are described in the Description of Work
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Description of Work: The applicant proposes the placement of fill material into the unnamed tributary of Elm Creek using earthen material and install the ABRS for approximately 2,194 lf. The proposed new stream channel would be constructed using an ABRS for approximately 1,382 lf that transition into an earthen grass trapezoidal channel for approximately 633 lf using 2:1 ratio side slopes. Fill material would consist of approximately 14,293 sq ft of fill material for bank stabilization would consist of four 16- by 24-inch (in) Capstone Block, 4 or 8 by 16 ft ABRS Block, and articulated mattress. The stream channel bottom and sidewall base is layered into earthen work for 7,625 cys, Type A topsoil for 611 cys, aggregated base for 555 cys, Class A concrete for 23 cys, Class C concrete for 40 cys, 9 lf for 18 in corrugated polyethylene pipe Type S, 55 lf for 18 in Reinforced Concrete Pipe (RCP) Class III, and 321 lf for 24 in RCP Class III.
The ABRS concrete bottom is designed to be 8 to 21 ft wide, with the sidewalls varying from 1 to 4 ft in height. The channel bottom and sidewall base is layered with 5.5 in thick washed 1.5 in rock wrapped with filter fabric. The work performed in the stream channel and uplands would be completed using conventional earthmoving equipment. All dredged material would be hauled off-site to an upland disposal area.
Avoidance and Minimization Information: The applicant provided the following statement with regard to how avoidance and minimization of impacts to aquatic resources was incorporated into the project plan:
Four alternatives configurations were considered during the preliminary design of the project.
Alternative 1: No Action
Alternative 2: Leave channel in existing location (outside easement and on private property) and stabilize slopes so that no further movement of the channel will occur.
Alternative 3: Realign channel back into easement using the articulated block mattress system to maintain the stream channel and construct a new vegetative trapezoidal in the upland. (Current Proposal)
The City has chosen Alternative 3 to align the channel back into the drainage easement.
Mitigation: Furthermore, the applicant proposes the following as compensatory mitigation for the unavoidable impacts to aquatic resources expected from the proposed project:
The City is proposing to use the ABRS in lieu of concrete-lining the stream channel. The City believes that compensatory mitigation should not be required for the proposal.
This mitigation plan is the applicant’s proposal. The Corps has made no determination at this time with regard to the adequacy of the proposed mitigation relative to the federal
mitigation rules and guidance, including Tulsa District’s Mitigation and Monitoring Guidelines. The Corps is accepting comments on the need for and nature of the proposed mitigation in addition to comments on the applicant’s primary proposal. The Corps bears the final decision on the need for and extent of mitigation required if the project proposed herein is authorized.