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HomeMy WebLinkAbout1.11 Revegetation & Noxious Weed PlansTRANSMISSION LINE 6584 REBUILD PROJECT ATTACHMENT L: Revegetation Plan and Weed Management Plan Transmission Line 6584 Rebuild Project L1: Revegetation Plan 1 Memo Date: Project: 6584 Mitchell Creek Substation to Ute Rifle Substation Electric Transmission Line Rebuild To: Garfield County, Colorado From: Brian Brown – HDR Engineering, Inc. Subject: Decommissioning/Reclamation Plan Public Service Company of Colorado (PSCo), a Colorado corporation conducting business as Xcel Energy, must replace the existing transmission line between the Mitchell Creek to UNA Rifle Substations. This line generally crosses rural undeveloped land. The new poles will be within the existing transmission easement and accessed via existing private or public roads and existing and new access routes. The intent of this Plan is layout Xcel’s approach to line decommissioning and reclamation of disturbed areas. Line Decommissioning Decommissioning of the line involves disconnecting the lines (overhead lines between poles) and removal of above ground poles to support the lines including guy wires and the wood pole structure. This process is typically as follows: · Erosion control measures per the Stormwater Management Plan (SWMP) permit will be implemented prior to construction activity. · Once the line is deenergized, overhead lines are disconnected via a bucket truck. · These lines will be removed during the decommissioning phase but the actual sequencing of such varies based on other factors that will be determined at the time of removal. · Cross arms may be removed once the lines are disconnected or once the pole is laid on the ground. · The soil at the base of the pole will be hand excavated approximately 1 foot deep with the excavated soil sitting immediately adjacent the excavation. · The grounding wire at the base of the pole will be removed. · Guy wires will be disconnected from the guy wire anchors. The below grade anchors will be abandoned in place. · The bucket truck will secure the pole to the elevated bucket. · The pole will be cut roughly 8 inches below the surrounding ground surface and placed horizontally on the ground or onto a truck in a controlled manner to be removed from the site. · The soil excavated from around the pole will be replaced into the excavation and over the void left by the pole removal. The base of the pole below grade will remain in place covered with soil. · SWMP maintenance and inspections will continue during construction in all on-going and post- construction areas until permit closure. February 22, 2024 2 Staging Area Staging area impacts for this project area expected to be minimal as staging areas are chosen for a number of characteristics includes a relatively flat area. Staging areas typically follow the same sequence of impacts and restoration: · Erosion control measures per the SWMP are implemented in compliance with permit conditions. This typically includes installation of a vehicle tracking control (VTC) which may be the only excavation disturbance associated with this construction. · Security fencing, if deemed necessary, will be installed. · Equipment, material, Conex, and trailer deliveries will begin. · The staging yard(s) will continue to be utilized as a place of material storage, staging, and assembly as well as a location for workers to park personal vehicles to minimize vehicle traffic along the Xcel ROW and crossing private property. · Typically, on flat staging yards, expected on this project, no further excavation is required. · After construction, remaining material, equipment, trailers, Conex, and fencing will be removed from the site. · Soil decompaction may be performed based on the agreement with the landowner. · Seed and mulch, unless agricultural crop land, will be placed per the conditions of the SWMP permit · SWMP inspections, maintenance, will continue until the site vegetation has been restored, SWMP maintenance and inspections will continue during construction in all on-going and post-construction areas until permit closure, excepting disturbed areas that will be utilized for crop production the following growing season. Reclamation While there are multiple construction types for this project, i.e. temporary pad grading, access grading, pole base excavation, etc., they are all fairly similar. Note: as this project is crossing mostly flat ground, therefore pad or access grading is expected to be isolated and very limited. Below is the general sequential approach to minimize disturbance and promote revegetation across the project. This will have to be slightly customized to each construction type and site conditions. 1. Prior to the start of construction, a surveyor will stake pole locations, off-sets, temporary construction areas, and other locations of importance where field delineation is beneficial. 2. Appropriate Xcel Energy staff, line construction contractor, foundation contractor, earthwork contractor, and erosion control contractor will meet on-site to review the delineated construction impact limits. 3. Flagging or paint used to delineate where perimeter erosion control measures should be placed based on disturbance limits defined by Xcel Energy construction team (item 2 above). 4. Xcel Energy erosion control plan developer, Xcel Energy Environmental Analysist, or erosion control install contractor may collect multiple representative topsoil soil samples for analysis along the transmission line. This analysis would focus on the potential for possible soil amendments (primarily nitrogen, phosphorus, and potassium) during seeding. 3 – 6 samples are expected based on the varying soil conditions along the line. 3 5. Erosion control contractor team will install perimeter erosion control measures, typically construction fence, boundary fence, sediment control logs, rock logs, and vehicle tracking control per the requirements identified in the State Stormwater Management Plan (SWMP). 6. Only as necessary for project, trim and remove vegetation for off-site disposal that will directly impact site grading or access. Xcel Energy to utilize trimming as much as practicable to keep root structure in place. 7. In areas where grading is required, strip topsoil (assume top 4 inches of soil) for reuse on site. Topsoil to be segregated from other material. Topsoil to be placed along access or in other areas adjacent grading. Topsoil may be transported from immediate work area due to space constraints. Topsoil that is stockpiled for more than 14 days will be seeded for temporary stabilization. Topsoil stockpiles that are to remain dormant for more than 14 days are to have side slopes no steeper than 1H:1V. 8. Topsoil stockpiles may be placed on undisturbed adjacent ground. In this event, Xcel Energy will place a separation fabric, i.e. Mirafi 140N or like, to provide a physical indicator as to where the stockpile ends and native ground begins. Xcel Energy has had success with this approach as it reduces unwanted disturbance of native ground and allows an undisturbed but lightly ‘compressed’ topsoil layer to bounce back once topsoil and separation fabric is removed. 9. Once permanent cut slopes are graded, they will be covered in topsoil within 14 days and seeded and mulched within another 14 days. This will allow permanent cut/fill face revegetation to commence as soon as possible. Work areas where active construction is anticipated, i.e. flat pads, are not to be topsoil covered until heavy construction work has ceased. Once heavy construction of permanent pads has ceased, topsoil cover is to be completed within 14 days and seeding and mulching to follow within another 14 days. 10. Subgrade excavation material, from grading or pole excavation, will be spread on the access road, exported from the site for off-site disposal, or stockpiled in immediate or near-by work area for future use, particularly in areas with temporary grading impacts that are to have grades restored. Like the topsoil above, subsoil that is stockpiled on undisturbed ground is to have a separation fabric below the stockpile to clearly distinguish between native grade and stockpile material. This will minimize disturbance of the native grade and allow this compressed native grade to bounce back once stockpile and separation fabric is removed. 11. Once construction is completed at a site for permanent grading impacts, i.e. conductor pull/tensioning pads and access roads, the site soil is to be ripped to loosen the subgrade due to soil compaction during construction. Following decompaction, topsoil is to be placed at a depth of 4 inches in a loose manner ready to accept seed. Unlike most topsoil requirements, rock of various gravel sizes less than 6 inches diameter may remain in the topsoil layer. 12. Once construction is completed at a site for temporary grading impacts, the site rough grades are to be reestablished and the subgrade soil is to be bucket compacted to a ‘firm’ condition. Following compaction, topsoil is to be placed at a depth of 4 inches in a smooth but loose manner ready to accept seed. Unlike most topsoil requirements, rock of various gravel sizes less than 6 inches diameter is expected in the topsoil layer and is indicative of native topsoil in this area. 13. Soil amendments 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 application, the seed mix may be 4 applied with the liquid amendment or hand broadcast but in no case is seed to be mixed and applied with mulch. 14. 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. 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 content with leads to a wildlife entrapment hazard. 15. 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. 16. 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 exposed or disturbed less vegetated soil. 17. 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. 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. Access for the post construction inspection and maintenance will be over prescriptive rights, landowner allowed access, and the transmission line easement. Seed Mix: A seed mix is proposed in the Noxious Weed Mitigation Plan and will be reviewed during construction in consultation with suppliers and appropriate County representatives, if requested. Transmission Line 6584 Rebuild Project L2: Weed Management Plan Noxious Weed Management Plan 6584 Mitchell Creek – Ute Rifle Line Rebuild Garfield County, Colorado February 22, 2024 _______________________________________________________ Prepared for: Xcel Energy PO BOX 840 Denver, Colorado 80201 (720) 963-3684 _______________________________________________________ Prepared by: HDR, Inc 1670 Broadway, Suite 3400 Denver, CO 80202 _______________________________________________________ Noxious Weed Management Plan | 6584 Mitchell Creek – Ute Rifle Line Rebuild TOC-i Contents Page No. Section 1. Introduction ................................................................................................................ 1 Section 2. Noxious Weed Management Requirements ............................................................... 1 2.1 Presidential Executive Order 13112—Invasive Species ..................................................... 1 2.2 Colorado Noxious Weed Act ............................................................................................. 1 2.3 Garfield County Noxious Weed Management .................................................................... 2 Section 3. Noxious Weed Control: Pre-construction .................................................................... 2 Section 4. Noxious Weed Control: During-Construction .............................................................. 3 Section 5. Noxious Weed Control – Post-Construction ............................................................... 3 5.1 Seed mix ........................................................................................................................... 5 Section 6. Recommended Management and Mitigation Actions .................................................. 6 Section 7. References ................................................................................................................ 7 Tables Table 1. Semi-Desert Loam Revegetation Seed Mixture* ................................................... 5 1 Section 1. Introduction Public Service Company of Colorado (PSCo), a Colorado corporation conducting business as Xcel Energy (Xcel Energy), is proposing to rebuild the 6584 Mitchell Creek - Ute Rifle overhead transmission line in Garfield County, Colorado. This Noxious Weed Management Plan (Plan) is based on typical practices and not on a site weed survey. This Plan has been prepared to support the expected noxious weed management activities for the line rebuild within Garfield County. Section 2. Noxious Weed Management Requirements When present in large numbers, noxious plant species have had considerable impacts to the quality and integrity of natural ecosystems. Noxious weed species can alter fire ecology, successional ecosystem processes, and ecosystem function of the ecosystems they invade. Some species have had such serious economic and biological impacts that their control and management is mandated under Colorado State law (i.e., List A species). Because of the adverse environmental effects of noxious weeds, federal, state, and local governments have issued various orders and regulations regarding noxious weeds. The following are some of the regulations guiding noxious weed management. 2.1 Presidential Executive Order 13112—Invasive Species Executive Order 13112, Invasive Species, was issued on February 3, 1999, to prevent the introduction of invasive species; provide for their control; and minimize the economic, ecological, and human health impacts that result from invasive species. This order directs federal agencies to prevent the introduction of invasive species, control and monitor invasive species, and restore native species and habitats that have been invaded (Federal Register 1999). 2.2 Colorado Noxious Weed Act As defined by the Colorado Department of Agriculture (CDOA), noxious weeds are plants that reduce agricultural productivity, lower real estate values, endanger human health and well-being, and damage scenic values (CDOA 2021a). The Colorado Noxious Weed Act §§ 35-5.5-101 through 119, C.R.S. as amended, states that an organized and coordinated effort must be made to stop the spread of noxious weeds. Rules pertaining to administration of the Act include a noxious weed list that designates and classifies noxious weed species into categories for immediate eradication (CDOA 2021a): · List A contains 25 species of noxious weeds targeted for eradication. If individuals or populations of A List species are found, the local governing body must provide the State Weed Coordinator with mapping that includes information on location and density of the infestation. · List B contains 38 species that are targeted for eradication, containment, or suppression based 2 upon a given local governing body’s management plan. · List C contains 16 species for which the Commissioner of Agriculture, in consultation with the state noxious weed advisory committee, local governments, and other interested parties, will develop and implement into state noxious weed management plans designed to support the efforts of local governing bodies to facilitate more effective integrated weed management on private and public lands. In addition to the three lists, the state maintains a noxious weed species “Watch List”. It contains 19 species that CDOA has determined pose a potential threat to the agricultural productivity and environmental values of the lands of Colorado. It is for advisory and education purposes only and is intended to encourage the collection of information needed to determine if the species should be listed as a noxious weed. 2.3 Garfield County Noxious Weed Management Garfield County adopted a Noxious Weed Management Plan to reduce the prevalence of noxious weeds and their negative impacts. The Garfield County Noxious Weed List includes 41 weeds. The County has a Weed Advisory Board to support the County in yearly determinations regarding weed list changes. The County’s principles of weed management are incorporated into the pre- and post-construction weed management activities, as appropriate. These include: · Prevention · Cultural Practices · Physical/mechanical methods · Biological Control · Chemical Control The term “noxious weed” includes species listed as noxious by the Colorado Department of Agriculture (CDOA 2021a) and additional plants listed as weeds within the County. Plant nomenclature for noxious weeds in this report follow the CDOA website. Section 3. Noxious Weed Control: Pre-construction Prior to construction, Xcel Energy will utilize the following steps to minimize noxious weed propagation: · Training of crews as to how surface disturbance creates a more favorable environment for noxious weeds if seed stock s in the area, · Delineating areas with boundary fence, see SWMP Plans and report, or a similar physical barrier to limit unnecessary surface disturbance, · Cleaning of equipment to avoid bringing non-native soil or vegetation onto the site as these may contain unwanted seed stock. Equipment brought to the site must be free of clean of soil or vegetation from another site. Thorough power washing of wheels, tracks, undercarriage, and excavation equipment will be performed prior to site arrival. Equipment that leaves the site, i.e. for crew transportation or equipment repair, and then 3 returns to the site without leaving pavement does not need to be rewashed. · A State Stormwater Management Plan (SWMP) permit that covers this construction activity will be obtained by Xcel Energy and the weed management steps will work in conjunction with the SWMP. Section 4. Noxious Weed Control: During- Construction Construction activities will expose soils in areas that have been previously disturbed and limited areas that have not been previously disturbed. This disturbance creates a potential for the introduction and spread of noxious weeds in the project area. Noxious weed species that occur in and adjacent to disturbed areas of the project have the potential to spread into areas impacted by placement of new poles, use and construction of access roads for construction equipment and use of staging areas. The goal of the plan is to minimize the spread of noxious weeds due to the proposed project’s construction activities. By implementing measures intended to minimize the spread of noxious weeds during construction and minimizing the establishment of new noxious weed populations post-construction, the proposed project should minimize new and help reduce existing noxious weed infestations. The activities during construction will, at a minimum, include: · Removal and stockpiling of topsoil for replacement in immediate area of excavation disturbance as this will create a more favorable soil strata for revegetation. · Leaving ‘drive & crush’ areas alone to rebound naturally. This assume the topsoil layer and associated root structure remains in place but has only been compressed by construction activity. · Crews will continue to be diligent about minimizing the construction impact to avoid topsoil disturbance. · Hand or drill seeding of appropriate seed mix has been applied along with mulch. · The SWMP permit compliance will continue during construction and the weed management steps will work in conjunction with the SWMP. Section 5. Noxious Weed Control – Post-Construction Post-construction activities are based on the assumption that the site grades and topsoil have been restored and appropriate seed mix has been applied. Post-construction weed control activities will commence in the year following completion of construction as that is when weed seed germination and growth is more apparent. NOTE: Weed control will only be addressed in areas disturbed by construction and will not address weed infestations outside of the disturbance area even if they are within Xcel Energy’s ROW. Post-construction weed management priorities are based on the threat noxious weed species found in the project area pose to the overall goal of maintaining the health of the ecosystem. Generally, List A species are the highest priority because they are often the most aggressive species with limited distribution. List B are next priority species and List C species are generally widespread and are not prioritized. 4 The best technique for controlling most established noxious weeds is an integrated approach of mechanical, biological, and chemical controls. Mechanical control usually involves mowing, hand-pulling, or cutting. Biological control is the use of organisms (usually insects, but also livestock) that are deliberately introduced to an area to control weeds. Chemical control involves the application of one or more herbicides at the appropriate time of the year (all herbicides should be applied by a certified applicator according to the manufacturer’s directions). Where chemical controls are recommended, Xcel Energy and its contractors work to minimize the use of chemicals that are harmful to beneficial insects in their vegetation management practices controlling shrubs, trees, and weed species within their rights-of-way and properties. This includes eliminating the use of neonicotinoids, a class of neuro-active insecticides, which have been found harmful to all invertebrate populations including bee populations and other native pollinators (Xcel Energy Undated). The year following construction, two noxious weed treatments will be undertaken: 1. Early season (May-June) for cool-season noxious weeds (e.g., redstem fillaree, cheatgrass, bindweed), 2. Late season (July-August) for the warm-season noxious weeds (e.g., thistles and knapweeds). Areas of infestations identified in these surveys will determine appropriate treatment and suppression methods. Noxious Weed Treatment Measures Xcel Energy’s noxious weed management contractor will implement noxious weed control measures in accordance with existing regulations and local requirements. Post-construction control measures can include one or more of the following methods (that may be implemented during restoration activities): · Treatment methods will be based on species-specific and area-specific conditions (e.g., proximity to water or riparian areas, agricultural areas, and time of year) with the County coordinator being notified prior to noxious weed eradication activities. If areas are not seeded until the following spring, Xcel Energy will alter weed treatment timing based on weed control best practices. · Mechanical methods rely on equipment that can be used to mow or disc weed populations. If such a method is used in areas to be restored, subsequent seeding will be conducted to re-establish a desirable vegetative cover that will stabilize the soils and slow the potential re-invasion of noxious weeds. · Discing or other mechanical treatments, that would disturb the soil surface within native habitats, will be avoided in favor of an herbicide application, which is an effective means of reducing the size of noxious weed populations as well as preventing the establishment of new colonies. 5 · Seed selection will be based on site-specific conditions and the appropriate seed mix identified for those conditions. · Herbicide applications will be controlled to minimize the impacts on the surrounding vegetation. In areas of dense infestation, a broader application will be used and a follow- up seeding program may be implemented. Refer to the Garfield County Noxious Weed Management Plan for recommended control techniques for noxious weed species. 5.1 Seed mix Restoration will consist of re-contouring the disturbed areas around poles and staging areas per grading plans and reseeding the area with the following seed mix. The timing of subsequent seeding efforts will be based on the life of applied herbicides, if used. NOTE: This seed mix will be reviewed during construction and in consultation with supplier and appropriate County representative. Table 1. Semi-Desert Loam Revegetation Seed Mixture* Species Pounds per Acre** Number of Seeds*** Western wheatgrass (Pascopyrum smithii) 3.00 8 Indian ricegrass (Achnatherum hymenoides) 2.00 6 Prairie junegrass (Koeleria macrantha) 0.50 26 Sandberg bluegrass (Poa secunda ssp. Sandbergii) 1.00 24 Galleta grass (Pleuraphis jamesii) 2.00 7 Bluebunch wheatgrass (Pseudoroegneria spicata ssp. Spicata) 2.00 6 Bottlebrush squirreltail (Elymus elymoides) 2.00 9 Total 12.50 85 *The seed mix shown in 1 was developed by Granite Seed and Erosion Control based on existing native grasses that occur in this region. Seed mix may be obtained from other suppliers. ** Pure Live Seed ***Per Square Foot 6 Section 6. Recommended Management and Mitigation Actions In addition to the specific management recommendations listed for each species in the Garfield County Noxious Weed Management Plan, the following mitigation measures are recommended (as appropriate) to minimize the spread of noxious weeds: · All construction equipment will remain in designated work areas. · The area of ground disturbance will be kept to the minimum necessary. · Minimize imported topsoil during construction. If importing is necessary, use certified weed-free soil. · All equipment will be thoroughly cleaned before entering and exiting the study area. · All mulches and straw used at the site will be certified weed-free. · All disturbed areas will be seeded after construction. Seeding will consist of species listed in Table 1. Semi-Desert Loam Seed Mixture will be spread on disturbed ground around poles and staging areas, as appropriate. The seed mix will be reviewed after the weed survey and in consultation suppliers and appropriate County representatives, as requested. · All seed mixes, soil, and other plant material used for revegetation will be free of noxious weed seeds, roots, and other propagules. · Only a Colorado-licensed Supervisor or Certified Operator will apply herbicides. · All herbicides will be applied in accordance with the manufacturer’s instructions. · Broadcast herbicide spraying will be limited to areas of project ground disturbance, around each existing and new pole, and at staging areas. Weed treatment around each existing and new pole will be limited to disturbance associated with this line rebuild. · The Garfield County Vegetation Manager will be notified prior to noxious weed treatments, as appropriate to the disturbance jurisdiction. · Applicable control measures (CMs) from the Stormwater Management Plan will be implemented. 7 Section 7. References Colorado Department of Agriculture (CDOA). 2021a. Noxious Weeds. Available online: <https://www.colorado.gov/pacific/agconservation/noxiousweeds> and <https://drive.google.com/file/d/0Bxn6NtpJWc9JRFE3LW1RWFVXY1E/view?resourcekey= 0-WalETB5Qp3zCjfRnar5t3g>. Accessed October 2021. CDOA. 2021b. County Weed Programs. Available online: County Weed Programs | Department of Agriculture (colorado.gov)>. Accessed October 2021. Colorado Department of Transportation (CDOT). 2021. Noxious Weeds Map. Available online: < https://cdot.maps.arcgis.com/home/webmap/viewer.html?webmap=ebd39c7a542349c6914 89f5ecb1a1c62#!>. Accessed October 2021. Colorado Natural Heritage Program (CNHP). 2016. Survey of Critical Biological Resources: a resurvey and update of Potential Conservation Areas in Garfield County, Colorado. Available online: https://cnhp.colostate.edu/wp- content/uploads/download/documents/2016/Final_Garfield_2016_report.pdf. Accessed October 2021. Garfield County Noxious Weed Management Plan, Revised February, 2016. Available online: Garfield-County-Noxious-Weed-Management-Plan-Adopted-Feb-2016.pdf U.S. Department of Agriculture (USDA). 2006. Land Resource Regions and Major Land Resource Areas of the United States, the Caribbean, and the Pacific Basin. Natural Resources Conservation Service, USDA Handbook 296. U.S. Geological Survey (USGS). 2021. National Land Cover Database (NLCD). Available online: https://apps.nationalmap.gov/viewer/. Accessed June 2021. Western Regional Climate Center. 2021. Climate Summaries. Available online: https://wrcc.dri.edu/Climate/summaries.php. Accessed October 2021. Xcel Energy. Undated. Wildlife and Habitat Protection. Available online: <https://www.xcelenergy.com/staticfiles/xe- responsive/Company/Corporate%20Responsibility%20Report/2019%20CRR/2019_Wildlife %20and%20Habitat%20Protection_CRR.pdf>. Accessed October 2021