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HomeMy WebLinkAboutENCLAVE AT REDWOOD - FDP220014 - SUBMITTAL DOCUMENTS - ROUND 1 - ENVIRONMENTAL REPORT Enclave at Redwood Native Habitat Buffer Zone Restoration and Annual Monitoring Plan July, 2021 PO Box 272150 Fort Collins, CO 80527 i Table of Contents 1.0 Introduction ................................................................................................................................ 1 2.0 Existing Site Conditions ................................................................................................................ 2 3.0 Restoration Plan .......................................................................................................................... 3 3.1 Goals and Objectives .............................................................................................................. 3 3.2 Step-by-Step Approach........................................................................................................... 4 4.0 Annual Monitoring Plan ................................................................................................................ 9 4.1 Schedule ............................................................................................................................... 9 4.2 Sampling Methodology ........................................................................................................... 9 4.3 Success Criteria ................................................................................................................... 10 5.0 Literature Cited and Data Sources .............................................................................................. 11 1.0 INTRODUCTION DR Horton has proposed the Enclave at Redwood development project, which will consist of 232 single - family units, a 1-acre park, a clubhouse with community amenities and several access roads which connect to existing roads. The Site is located east of Redwood Street in Fort Collins, Larimer County, Colorado and consists of approximately 27.85-acre tract of vacant land which is bordered at the east by the Lake Canal and surrounded by developed community homes in the remaining directions. The Site is zoned Low-Density Mixed-Use Neighborhood (LMN). An Ecological Characterization Study (ECS) was performed in 2018 by Terracon Consultants, Inc. (Terracon) as required by Article 3, Section 3.4.1 of the City of Fort Collins (City) Land Use Code (LUC). The ECS informed the City’s determination that the natural habitats on Site will require the implementation of a Natural Habitat Buffer Zone (NHBZ) to mitigate potential impacts from development on ecological character and quality. An additional evaluation of the NHBZ was performed in April 2021 by Cedar Creek Associates, Inc. (Cedar Creek) to confirm that Site conditions are consistent with those described in the ECS a nd determine the extent of noxious weed populations on the Site. Cedar Creek also executed a wetland delineation of the drainage ditch that runs along the northern border of the Site in May 2021. The Proposed Development Plan (PDP) presents the NHBZ delineations on Site, which have been modified from the standard 50’ stipulated boundaries in accordance with LUC guidelines. Approval of the proposed NHBZ delineation is contingent upon the Applicant completing additional mitigation requirements prescribed by the City’s Environmental Planning Department. This NHBZ Restoration and Annual Monitoring Plan (Plan) presents recommended restoration and monitoring approaches which have been designed to ascertain measurable habitat improvement in the NHBZ. The objective of this Plan is to describe the methods and procedures that will be used to implement restoration, assess establishment and progress of restoration, identify potential issues, and gather information used to inform adaptive management activities. Restoration design for the proposed stormwater drainage pond has been incorporated into this document the extent possible based on t he City’s Landscape Design Standards and Guidelines for Stormwater Detention Facilities (2009). Weed management is discussed within the broader context of our proposed approach in this document and detailed more specifically in the Weed Management Plan (Ce dar Creek 2021). 2.0 EXISTING SITE CONDITIONS Results of April and May 2021 field evaluations indicate the majority of the Site can be characterized as non-native grassland, most of which is dominated by either a near monoculture of smooth brome (Bromus inermis) or noxious and weedy annual species. Noxious weeds observed on Site in April 2021 include cheatgrass (Bromus tectorum), Russian olive, leafy spurge (Euphorbia esula), and common mullein (Verbascum thapsus). Existing conditions and management strategies for these species are described in the Weed Management Plan. Evidence of past disturbance activities can be found throughout the Site, including drainage swales, unmaintained and revegetated irrigation ditches, former roads/vehicle use, and several berms and/or stockpiles of soil. These formerly disturbed areas have high concentrations of noxious weeds, though most species are evident throughout the Site. Approximately ~20 Russian Olive trees can be found on Site, most of which are mature and to the north. A 0.36-acre wetland is contained by the stormwater ditch that runs along the north border of the Site. Results of the Site assessment and an evaluation of aerial imagery indicates that this extent of wetland vegetation is likely highly variable from year to year, especially in the eastern half where wetland classification was borderline. The western half exhibited high capacity for water retention compared to the east, holding surface water after a heavy precipitation event for much longer than to the east. Vegetation in the wetland is dominated by Timothygrass (Phleum pratense), Kentucky bluegrass (Poa pratensis), and/or Baltic rush (Juncus balticus), interspersed with native species. The banks of the stormwater ditch are regularly mowed, and it is possible that the wetlands themselves are mowed before/early in the growing season based on what look to be tire tracks. In addition, there is existing disturbance near the westernmost start of the drainage ditch, including deep tire ruts that cut over the wetland and up the opposite slope. Riparian vegetation along Lake Canal, which was dry at the time of the April evaluation, is dominated primarily by either smooth brome or plains cottonwood (Populus deltoides). The banks along Lake Canal are in overall poor condition, varying between 3-8 feet high and moderately to highly incised along the majority of its length. There are several other drainage features just adjacent to the Site that contain potential or defined wetlands, the stipulated buffers for which have been accounted for in the NHBZ. 3.0 RESTORATION PLAN 3.1 Goals and Objectives In accordance with the City of Fort Collins guidelines (LUC 3.4.1) the NHBZ should be managed to: 1. Preserve or enhance the ecological character or function and wildlife use of the natural habitat or feature and to minimize or adequately mitigate the foreseeable impacts of development. 2. Preserve or enhance the existence of wildlife movement corridors between natural habitats and features, both within and adjacent to the Site. 3. Enhance the natural ecological characteristics of the Site. If existing landscaping within the NHBZ is determined by the decision maker to be incompatible with the purposes of the b uffer zone, then the applicant shall undertake restoration and mitigation measures such as re -grading and/or the replanting of native vegetation. 4. Provide appropriate human access to natural habitats and features and their associated NHBZ’S in order to serve recreation purposes, provided that such access is compatible with the ecological character or wildlife use of the natural habitat or feature. The restoration approach and monitoring presented in this Plan has been developed to support the meeting of NHBZ goals through evaluation of revegetation establishment and progression. Monitoring results can be used to identify problem areas or potential issues early in the restoration process, inform adaptive management activities (i.e., weed management), and assess progress towards the meeting of success criteria indicative favorable NHBZ restoration and management. The overall management goal of the NHBZ is preservation of existing conditions. However, when ground disturbance is planned within the NHBZ, the following restoration process should be implemented to enhance the ecological character of the area . Additionally, guidelines for restoration of the proposed stormwater detention pond have been incorporated into the following process. However, the desig n of that feature, which includes restoration, design, and engineering components, should be implemented in accordance with the City’s standards and guidelines (2009). 3.2 Step-by-Step Approach The following is a recommended step-by-step process designed to reduce cost, improve the ecological function, and enhance the ecological characteristics of the NHBZ while maintaining flexibility for site-specific conditions. Step 1. Creating Opportunity and Reducing Competition The noxious and weedy species are often non-native, aggressive spreaders, and usually considered undesirable ecologically and aesthetically. If left unmanaged, they can dominate an ecosystem by native and less competitive species, which for those reasons are typically considered more desirable species. Therefore, creating opportunities for a variety of native species to establish is vital. Some method of vegetation control must be used on the undesirable aggressive species. Typically, mechanical or chemical control is used. Mechanical control entails scraping or plowing to increase bare ground exposure which will serve as a seedbed / planting medium. Chemical control entails the use of herbicide to diminish dominance of undesirable and noxious species (see Weed Management Plan). Smooth brome is rhizomatous spread by wind-driven cross-fertilization to produce seeds and can propagate vegetatively through tillering and root fragments. Therefore, a chemical treatment is highly recommended prior to initiating mechanical manipulation of soil. Vegetation in the NHBZ is dominated by smooth brome, an aggressive, non-native, perennial grass, interspersed with noxious and weedy forbs. While smooth brome is an undesirable species with regard to biodiversity it does provide excellent soil stability and forage potential for wildlife. Therefore, a total eradication of this species may not be necessary, but it should be treated when beneficial to reduce competition and encourage the establishment of native vegetation. Step 2. Soil Preparation The soil surface should be optimized for seeding or planting. An agronomic assessment is recommended to evaluate the chemical and physical properties of the soil throughout the Site, and a required design standard in the location of the proposed stormwater detention pond. This information can be used to determine whether soil amendments (i.e. compost) would benefit the establishing plant communities and allow for optimization of the seed mix to soil conditions. Planted areas in the stormwater detention pond will require topsoil with appropriate levels of organic matter and should receive imported or stockpiled topsoil to a minimum depth of four inches. Sub-grade should be loosened to a depth of 12 inches total (8” existing sub-grade and 4” of new topsoil) in the stormwater detention pond location and 10 inches throughout the remainder of the Site. Stones, clods, sticks, rubbish, and other matter large enough to impede planting, seeding, or mowing should be collected and removed from the Site. Removed material must be disposed legally. Repeat cultivation in areas where equipment used for hauling and spreading topsoil has recompacted the soil. Fine grade disturbed areas to a smooth, uniform surface plane. Prior to seeding the soil surface should be loose, allowing for good soil/seed contact. Roll and rake, remove ridges, and fill depressions to meet surface grades based on grading plans. Step 3. Seeding and Planting In general, the species used should be native and suitable to the soil and moisture conditions of the Buffer. Seed mixes should be designed to facilitate growth of appropriate and sustainable species. If changes are to be made to the proposed seed mix based on Site conditions, then approval must be provided by a city Environmental Planner. The proposed seed mix was based on the City’s recommended species and is presented in Table 1 below. After final contouring and amendment application/incorporation, seedi ng should occur as soon as possible to avoid undesirable impacts from wind or precipitation. Seeding can be accomplished using broadcasting and drilling techniques wherever applicable. • For broadcast seeding: the seeding rate should be doubled, seed -to soil contact should be increased immediately through manipulation which will also provide some protection from wind or water erosion and granivores. Manipulation can be accomplished by either a light disc harrowing perpendicular to the flow of energy (wind and/or water) or hand raking around sensitive areas (i.e. willow patches). • For drill seeding: final drilling pass must occur on the contour, to create subtle ridges perpendicular to the flow of energy. Drill seeding should not be conducted in sensitive areas. Appropriate native seeding equipment will be used, which does not include standard turf seeding equipment or agriculture equipment. Drill seed the approved mix in two passes, each at a right angles to the other and using half the seed in each pass. Seed should be drilled at the specified application rate and to a depth of no greater than ½ inch. If areas are too wet or steep to drill seed, broadcast seed in opposite directions at twice the application rate used for drill seeding. Restore fine grade after seeding, and cover seed to a depth of ¼ of an inch by raking or dragging. Firm seeded areas with a roller weighing a maximum of 100 lbs. per foot of width. Plantings and/or plugs of wetland species is recommended in the stormwater detention pond in the event that inundation or saturation precludes seeding. If necessary, these plantings should be concentrated in areas with high risk of erosion to minimize the risk of soil loss. Planting should also be concentrated where favorable moisture zones are likely to exist. Planting small plugs in the fall is not desirable due to the loss of plants to Canada Geese (Branta canadensis). Subsequent plantings are recommended after initial establishment and when weeds are controlled (2-5 growing seasons after initial construction). These plantings can be concentrated in areas needing additional erosion control protection and/or bare areas. No.Common Name Scientific Nomenclature PLS / lb. Recommd. PLS lbs/ac PLS / ft 2 % of Seeds in Mix PLAINS COREPSIS COREOPSIS TINCTORIA 1,400,000 0.17 5.5 8.0% PURPLE PRAIRIE CLOVER DALEA PURPUREA 210,000 0.81 3.9 5.7% INDIAN BLANKETFLOWER GAILLARDIA ARISTATA 132,000 1.85 5.6 8.2% ROCKY MOUNTAIN PENSTEMON PENSTEMON STRICTUS 592,000 0.35 4.8 6.9% MEXICAN HAT RATIBIDA COLUMNIFERA 737,000 0.20 3.4 4.9% Forb Subtotal 3.38 23.1 33.7% INDIAN RICEGRASS ACHNATHERUM HYMENOIDES 141,000 1.13 3.7 5.3% SIDEOATS GRAMA BOUTELOUA CURTIPENDULA 191,000 1.15 5.0 7.3% BUFFALOGRASS BUCHLOE DACTYLOIDES 56,000 3.27 4.2 6.1% BLUE GRAMA BOUTELOUA GRACILIS 825,000 0.25 4.7 6.9% BOTTLEBRUSH SQUIRRELTAIL ELYMUS ELYMOIDES 192,000 0.95 4.2 6.1% PRAIRIE JUNEGRASS KOELERIA MACRANTHA 2,315,400 0.08 4.3 6.2% GREEN NEEDLEGRASS NASSELLA VIRIDULA 181,000 1.01 4.2 6.1% SWITCHGRASS PANICUM VIRGATUM 389,000 0.71 6.3 9.2% WESTERN WHEAT PASCOPYRUM SMITHII 110,000 1.61 4.1 5.9% SAND DROPSEED SPOROBOLUS CRYPTANDRUS 5,298,000 0.04 4.9 7.1% Grasses Subtotal 10.20 45.5 66.3% Total for Upland Mix 13.58 68.7 100.0% Acceptable Substitutes PLS / lb. Recommd. PLS lbs/ac PLS / ft 2 FRINGED SAGEWORT ARTEMISIA FRIGIDA 4,536,000 0.06 6.2 BLUE FLAX LINUM LEWISII 293,000 0.41 2.8 PRAIRIE ASTER MACHAERANTHERA TANACETIFOLIA 408,000 0.25 2.3 CANADA WILDRYE ELYMUS CANADENSIS 115,000 1.59 4.2 INLAND SALTGRASS DISTICHLIS STRICTA 520,000 0.35 4.2 MOUNTAIN MUHLY MUHLENBERGIA MONTANA 1,500,000 0.11 3.8 RequirementsGrassesForbsGrasses*Contractor is responsible for locating and purchasing all species listed in mix. If a species cant be located, contractor must replace each missing species with the acceptable substitutions (listed above). Contractor is responsible for providing seed tags to appropriate City staff. This mix is based on 70 seeds/ square foot and is only calculated for one acre. This mix is based on the contractor using a drill seed application. Mix should be doubled if hand broadcasted. Contractor is responsible for calculating the appropriate seed amounts to purchase. Please note that the pounds per acre are in PLS (Pure Live Seed) and must be ordered that way. All materials finished shall be free of Colorado State noxious weeds as defined in Article III, Section 21-40 of the Code of the City of Fort Collins. Specifications / Recommendations Wildflowers/ ForbsTable 1. Suggested Seed Mix Upland Mix Planting or seeding of native shrubs should occur to provide structural diversity. Species to be used should be approved by a City Environmental Planner. Shrubs should be planted using industry Best Management Practices. The following native shrubs, sub-shrubs, and agavoids are recommended for planting in upland areas, based on the NRCS Web Soil Survey results for the Site: • Fourwing Saltbush (Atriplex canescens) • Rubber Rabbitbrush (Ericameria nauseosa var. nauseosa) • Winterfat (Krascheninnikovia lanata) • Prairie Sagewort (Artemisia frigida) • Soapweed Yucca (Yucca glauca) Additional shrub species which may be more suited for planting in mesic areas, such as the proposed stormwater detention pond, include the following: • Currants (Ribes aureum and/or R. cereum) • Various willows (Salix spp.) • Chokecherry (Prunus virginiana) • Skunkbush sumac (Rhus trilobata) • Snowberry (Symphoricarpos occidentalis) • Redosier dogwood (Cornus sericea). Step 4. Maintenance and Management Maintenance and management activities should be implemented to ensure success of the ecological restoration project. After seeding, the area shall be covered with crimped straw, jute mesh, or other appropriate soil surface stabilization methods. Straw mulch should be certified weed-free hay or certified weed-free straw with no seed heads. In the stormwater drainage area, natural fiber blankets are recommended, as synthetic blankets can entangle reptiles and amphibians in aquatic habitats. Routine inspections for erosion should be performed during the time between seeding and vegetation establishment to assure no excessive erosion features form on t he project area. Restoration goals can be achieved without the use of supplemental water if seedling plans correspond to local climatic patterns for native seeding, late fall or early spring. Supplemental irrigation can have substantial effects on the trajectory of the establishing plant community that can negatively affect Site diversity and self-sustainability (USFS 1984). For example, supplemental water can negate important Site characteristics such as micro-topographic features, while also providing a competitive advantage to sod- forming or more quickly growing species, leading to decreased structural diversity throughout the Site. Species proposed in this restoration plan are native species which are adapted to local climatic conditions and should be able to establish under natural conditions. By not applying supplemental water, the development of a more diverse, drought tolerant, and ultimately more resilient and sustainable ecosystem will be allowed to establish at the Site. The Weed Management Plan (Cedar Creek 2021) provided for the Site will be implemented to ensure that weeds are properly managed before, during, and after seeding activities. Overall, the contractor shall monitor seeded area for erosion control, germination, and reseeding as needed to establish cover. 4.0 ANNUAL MONITORING PLAN The applicant will be responsible for ensuring execution of the monitoring and reporting protocol described below. 4.1 Schedule The NHBZ will be surveyed twice a year on the following schedule: 1. In the spring, a qualified ecologist will traverse the entirety of the Site to assess noxious weed populations prior to implementation of management strategies. This effort will result in optimized and targeted weed control efforts and provide sufficient time to manage weeds prior to seed production. 2. At the peak of growing season, a qualified ecologist will implement the quantitative procedure described in section 4.2 to measure ground cover within the NHBZ. The ecologist will also traverse the entirety of the Site to identify potential problems or issues with restoration. During these traverses, the observer will take note of: areas of poor seedling emergence, indicators of soil fertility problems, noxious weeds or invasive plant infestation , expectations for noxious weed seeding/flowering, excessive erosion, untreated cattail populations in the stormwater detention pond, and any other similar revegetation / restoration related issues (if observed). Annual monitoring will continue for a total of three years following restoration of the NHBZ. A brief memo containing survey findings and recommendations will be provided to the City of Fort Collins by September 30th of each year. This will give the City of Fort Collins and the applicant ample time to discuss and implement adaptive management to address any underperforming areas prior to when on -the-ground treatment implementation would be needed, if determined necessary. 4.2 Permanent Photo-points Ten permanent photo-point (marked with GPS coordinates) on the Site will be established to visually catalog vegetation progress; 4 along Lake Canal, 1 in the uplands of the undeveloped parcel south of Suniga Drive, 2 in the proposed stormwater retention area, and 3 in the Area for Conservation. Photo-points should be determined in the field at a location representative of the NHBZ area, each location marked with GPS coordinates, and each designated with a number which will remain consistent throughout the 3 -year monitoring period. Each photo-point should be documented during the summer evaluation at the peak of the growing season, for each of the annual monitoring efforts that will follow restoration. At each point, four photos will be collected, one each in a cardinal compass direction (N-E-S-W), using a photo board that is visible in each frame to indicate the photo-point number. 4.3 Sampling Methodology Cover sampling will be conducted at a minimum of 15 sample points in the reclaimed areas of the NHBZ to assess progress towards standards. A minimum of 5 sample points should be located in the wetland designated Area to be Conserved, in order to assess the retention of existing character. At each sample point, ground cover will be measured using ocular estimates in a 1 meter by 1 meter quadrat. Sample locations will be determined randomly prior to field evaluation. Upon reaching the sample point, the quadrat will be placed on the ground and the ecologist will estimate and record vegetative ground cover by species to the nearest 1%. All species, including noxious and invasive species, and their respective percent ground cover will be recorded. In addition, percent cover of litter, rock, and bare ground exposure will be estimated and recorded; when summed w ith vegetation estimates, these will produce 100% coverage of ground cover at each sample point. 4.4 Success Criteria During the third year of annual monitoring, a determination of successful establishment in the NHBZ will be made by City Environmental Planning Department based on a Site surveys and vegetative performance compared to success criteria. The developer and/or landscape contractor is responsible for adequate seedling coverage and growth at the time of final stabilization, as defined by state and l ocal agencies. Restored vegetation communities will be considered established when an effort to achieve the NHBZ goals has been demonstrated through mitigation and/or reclamation efforts and all of the following are met: 1. 70% total vegetative cover (excluding noxious weeds) is reached with no bare spots larger than one square-foot. 2. Noxious weeds do not exceed 10% total cover. 3. Deemed acceptable by City Environmental Planning Department and erosion control. City Environmental Planning Department has the authority to deem revegetation established in lieu of meeting success criteria, as well as withhold approval despite meeting success criteria, if they so choose . If final stabilization is not achieved to the satisfaction of the agency, the develop er and/or landscape contractor shall be responsible for additional corrective measures to satisfy final vegetative requirements for closeout. 5.0 LITERATURE CITED AND DATA SOURCES City of Fort Collins. 2021. Land Use Code. March 5, 2021. Cedar Creek Associates, Inc. 2021. Enclave at Redwood Natural Habitat Buffer Zone Weed Management Plan. May, 2021. Terracon. 2018. Ecological Characterization Study for the Retreat at Fort Collins . March, 2018. United States Forest Service (USFS). 1984. Brown, D.; Hallman, R.G. Reclaiming Disturbed Lands.