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HomeMy WebLinkAbout20240815 6584 Staging Yards Vegetation Reclamation Plan1 Memo Date: Wednesday, August 14, 2024 Project: 6584 TLine: Mitchell (MITC) - Rifle (UTER) Electric Transmission Line Rebuild - McLin and Murray Staging Areas. To: Garfield County , Colorado From: Brian Brown – HDR Engineering, Inc. Subject: Reclamation Plan Public Service Company of Colorado (PSCo), a Colorado corporation conducting business as Xcel Energy (Xcel), must replace the existing transmission line between the Mitchell Creek (MITC) to (UTER) Rifle Substations. This line generally crosses rural undeveloped land. T he new poles will be within the existing transmission easement and accessed via existing private or public roads and existing and new access routes . In support of this line rebuild, Xcel has secured two staging/material yards to store equipment, limited equipment assembly, and staff coordination. As the Garfield County permitting will only cover the staging yards, this R evegetation Plan will only address the staging yards. The erosion control and revegetation of the transmission line will be covered and completed per conditions of the State SWMP permit. See the associated maps and figures that are part of the County submittal for locations and improvements to support this Reclamation Plan. Staging Areas Erosion Control and Reclamation Both staging yards, the McLin Yard and the Murray Yard, are similarly designed with the “show up” portion of the yard aggregate covered and the remainder of the yard unaltered. The “show up” portion of the yard is shown on the SWMP submittal as a Stabilized Staging Area (SSA) and contains crew parking, Conex containers, trailers, etc. There are no substantive grading changes to either yard with the only site ‘grading’ limited to removing and stockpiling topsoil to create the aggregate covered SSA. The McLin and Murray s taging areas typically follow the same sequence of impacts and restoration as spelled out below. • Appropriate Xcel, and construction, and erosion control staff will meet on -site immediately prior to the yard construction/use to review the delineated construction impact limits and verify plan meets intended use or is minor adjustments are needed. If the County requires a pre -construction meeting, this would be the time for such to occur. • Xcel erosion control plan developer, Xcel Energy Environmental Analysist, or erosion control install contractor may collect representative topsoil soil samples for analysis in the SSA footprint. This analysis 2 would focus on the potential for possible soil amendments (primarily nitrogen, phosphorus, and potassium) during seeding. 2-3 samples would be typical for the proposed SSA area. • Erosion control measures per the SWMP are implemented in compliance with permit conditions. This typically includes installation of a vehicle tracking control (VTC), limited fencing to prevent impacts to sensitive areas or existing infrastructure , and perimeter Control Measures (CMs) to minimize sediment transport from the project area. • Creation of a Stabilized Staging Area (SSA). An SSA is an aggregate surfaced area that experiences the highest volume of traffic and turning action. The area is stabilized to minimize disturbance, rutting, and sediment track out. o Delineate SSA as shown on SWMP/Grading Plans. o Strip topsoil within SSA. o Stockpile topsoil immediately upgradient of SSA, install down-gradient erosion control measures, and temporarily seed stockpile. o Place aggregate surfacing. • Deliver and arrange equipment, material, Conex, and trailer s, etc. around site. • Beyond the SSA area, traffic of the yard will be primarily for material drop off and material pickup and limited material assembly. Therefore, the yard will remain in the current vegetated state and access and use of the yard will be drive and crush over existing vegetation. This typically leaves the root zone intact and promotes a faster rebound of revegetat ion after demobilization in low traffic areas. • After construction, remaining material, equipment, trailers, Conex, and fencing will be removed from the site along with removal of the SSA aggregate. • Soil decompaction to be performed in compacted areas, primarily in the SSA area. • The SSA topsoil stockpile is to be placed into aggregate stripped SSA area to depths generally matching the pre-construction grades of area. Topsoil will be prepared to accept seed. Note that the presence of rock in the topsoil will generally match the occurrence of rock typical of the yard. • Areas of drive & crush that experienced rutting disturbing may be seeded and mulched. Rutting is defined as greater than 3” depth or when the rut is deeper than the topsoil depth. Determination of where seeding & mulch will occur in rutted areas will be the responsibility of the erosion control inspector or Xcel Environmental Services with the intent of reestablishing area vegetation. • Soil amendments, if recommended in the SSA, are to be added per soil analytic recommendations via mechanical broadcast or hydraulic application. • Site seed mix is to be spread at appropriate rates given application type, hydraulic, drill, or hand broadcast. The amendment and seed application will vary substantially based on disturbance type site access and soil conditions. In cases of hydraulic appli cation, the seed mix may be applied with the liquid amendment or hand broadcast , but in no case is seed to be mixed and applied with mulch. • Seed and mulch, unless agricultural crop land, will be placed per the conditions of the SWMP permit and the County Grading permit. • Final erosion control cover for seeded areas will vary based on access to disturbance areas. Truck or tracked access areas will have either straw crimp mulch (on grades less than 10 percent and low rock content soil) or a high quality hydraulically applied mulch, i.e. Flexterra HP-FGM or like, on grades exceeding 10 percent or high rock content . Xcel Energy generally does not support using erosion control blankets on this project due to concerns about reduced blanket to soil contact and due to longer life blankets having a high synthetic material content with is a wildlife entrapment hazard. 3 • Xcel Energy will change erosion control inspection schedule from weekly to monthly inspections once initial stabilization measures (seeding and mulching) have been completed. If there are areas of concern identified during the monthly inspection that need to be addressed (i.e. erosion or lack of revegetation growth), the revegetation contractor will return to the site to address identified issues. • Per the required State (SWMP) and local (Grading Permits), Xcel Energy will continue to maintain structural erosion control measures across the project until no longer necessary. These will primarily include down-gradient sediment control logs but may include other control measures. These measures will be removed when no longer required and seed will be hand broadcast in areas where removal has created a disturbance and removed/killed vegetation. • Once site has met plant density cover requirements, Xcel Energy will perform a final post -construction site visit to document final conditions and then Xcel Energy will close SWMP permit with the State. • See the Noxious Weed Report for each yard regarding weed management and treatment during the revegetation period. NOTES: • Xcel Energy’s ability to stabilize disturbed areas with vegetation is dependent on many factors within Xcel Energy control. Unfortunately, favorable moisture conditions for germination and continued growth are beyond Xcel Energy control and a key determinate for revegetation. Xcel Energy anticipates adequate revegetation will take multiple years. Xcel Energy frequently returns to sites multiple times that are in the vegetation growth phase to address areas of erosion and reseed and/or mulch as necessary to promote vegetation stabilization. • Xcel Energy hires a separate third-party company to perform the erosion control installation, maintenance, and revegetation as well as another third-party company to perform regular erosion control inspections. These companies have long standing relationships with Xcel Energy. With this approach, Xcel Energy has trained the installation company and inspection company to meet Xcel Energy’s standards and to stay in compliance with state and local permit conditions which improve the restoration trajectory. Xcel’s practice is to continue inspection and maintenance, both performed by third party contractors, until site revegetation is established. Seed Mix: A seed mix with pollinator species is included in the SWMP Report for each individual yard.