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HomeMy WebLinkAboutSP-24-20 - Supplemental - 0200 da Vinci Drive (2) 180 Market Street, South Burlington, Vermont 05403 | 802-846-4106 | www.southburlingtonvt.gov TO: South Burlington Development Review Board FROM: Marla Keene, Development Review Planner SUBJECT: #SP-24-20 200 Davinci Drive DATE: June 18, 2024 Development Review Board meeting PROJECT DESCRIPTION Site plan application #SP-24-20 of Burlington School District to amend a previously approved plan for an airport complex. The amendment consists of renovating an existing hangar for the use of Burlington School District’s Aviation Technical Center, including reconfiguration of the parking and site circulation, 200 Davinci Drive. COMMENTS The Board reviewed this application on June 4, 2024. The Board continued the hearing for the purpose of allowing review of the revised materials submitted at the June 4 hearing date. This memo focuses on items for which no conclusion was reached on June 4, 2024, including discussion of the materials presented on that date. As always, the Board is welcome to bring up any concerns with the revised plans that are not highlighted herein. The Board is also reviewing the related master plan amendment at the June 18 hearing. A) SITE PLAN REVIEW STANDARDS 14.06 General Review Standards A. Relationship of Proposed Structures to the Site. (1) The site shall be planned to accomplish a desirable transition from structure to site, from structure to structure, and to provide for adequate planting, safe pedestrian movement, and adequate parking areas. The comment on this criterion in the June 4 Staff report focused on improving access to the site for users that are not arriving in cars or buses given the proposed use of the building for students, and the City’s prioritization of personal mobility (ie biking and walking). In response to the June 4 report, the applicant has added an on-grade striped walkway from the building across Davinci Drive to the existing sidewalk. Staff is strongly in support of a crossing of Davinci Drive but has concerns about the proposed crosswalk location relative to the 40-ft wide driveway that access both the proposed technical center and the Beta loading dock area, highlighted in pink below, as well as the location of the walkway relative to the driveway the applicant has testified is necessary for bus movements, highlighted in green below. #SP-24-20 2 1. Staff recommends the Board direct the applicant to relocate the crosswalk and walkway to a location that will provide safe pedestrian movement. 14.07 Specific Review Standards C. Access and Circulation. All proposed development shall comply with site access and circulation standards of Section 15.A.14. The applicant is proposing to modify the access and circulation in front of the existing hangars to the west of the subject building by formalizing one parking area, expanding another, and realigning and widening the driveway at the east end of the parking areas. They are not proposing modifications to the access and circulation in front of the subject building. Relevant standards of 15.A.14 include those pertaining to safe pedestrian access and to minimizing curb cuts by providing shared vehicular access. Davinci Drive is not currently a public street, but there is an irrevocable offer of dedication to the City therefore it should be treated as a public street for the purposes of layout and design. On June 4, the Board asked the applicant to demonstrate that the proposed pavement is minimized near the entrance to Davinci Drive, where there are four non-perpendicular vehicle movements proposed to occur. The applicant verbally stated that they have performed a turning movement analysis, but did not provide it. Members expressed interest in seeing that the pavement has been minimized. 2. Staff recommends the Board ask the applicant to provide a turning movement plan showing how the proposed configuration is optimized to minimize pavement and maximize pedestrian safety. H. Utility Services. Electric, telephone and other wire-served utility lines and service connections shall be underground insofar as feasible and subject to state public utilities regulations. Any utility installations remaining above ground shall be located so as to have a harmonious relation to neighboring properties and to the site. Standards of Section 15.A.18, Infrastructure, Utilities, and Services, shall also be met. #SP-24-20 3 The property is currently served by overhead utilities. The applicant testified that the utilities are underground from the utility pole near Davinci Drive to the building, and that it will remain so. Staff recommends the Board include a condition of approval requiring the line type on the plans to be updated to reflect that the utilities are underground. B) SUPPLEMENTAL REGULATIONS 13.02 Off Street Parking and Loading G. Design requirements for Parking Spaces, Parking Aisles, Lighting and Landscaping (1) Design requirements for off-street parking and loading are provided in Table 13-2 and Figure 13-1, Section 13.04, Landscaping , Screening, and Street Trees, and Section 13.07, Exterior Lighting. All paved parking spaces shall be striped or otherwise physically delimited. Sections 13.04 and 13.07 are discussed below. Parking is proposed to meet the required dimensional standards. (2) The location of parking areas and loading docks shall prevent conflicts with entering and existing traffic onto a public street and prevent conflicts between vehicles and pedestrians. The distance between access points and parking areas shall be adequate to minimize blockage and prevent back-ups onto the public street. Staff considers this criterion met. (3) Provision shall be made for access by police, fire and emergency vehicles. The Fire Marshal reviewed the project on 5/22/2024 and indicated there were no comments pertaining to the Development Review Board’s review of the project. (4) Pedestrian safety. Insofar as practicable, pedestrian and bicycle circulation shall be separated from motor vehicle circulation. Safe and convenient pedestrian circulation, including appropriate sidewalks, shall be provided on the site and its approaches. The pedestrian circulation on site shall be designed to minimize adverse effects of vehicular traffic on sidewalks and recreation paths. The applicant is proposing an on-grade striped pathway from the parking area to the building. On June 4, the applicant testified that they cannot provide a curbed sidewalk because the pavement needs to be flat in order to drain. Staff has reviewed the provided grading plans and watershed plans and is unable to reconcile the statement made by the applicant with the provided plans. It appears that if the sidewalk were raised, excess runoff from the pervious area north of the sidewalk would flow overland to the proposed bioretention area, and runoff from the proposed pavement would run along the curb to the proposed bioretention area. 3. Staff recommends the Board direct the applicant to raise the sidewalk so that it is protected from the drive aisle by curbing or in another manner. 13.03 Bicycle Parking and Storage. As discussed on June 4, the applicant is required to provide at least 5 short term bicycle parking spaces. The applicant testified that they are proposing 8 short term and 2 long term spaces. The required short term spaces are shown on the enlarged entrance plan, sheet SP-02. #SP-24-20 4 13.04 Landscaping, Screening & Street Trees B. Except for parking spaces accessory to a one-family or two-family dwelling, all off-street parking areas subject to review by the Development Review Board shall be curbed and landscaped with appropriate trees, shrubs, and other plants including ground covers, as approved by the Development Review Board. Sections of recessed curb are permitted if their purpose is to allow stormwater runoff from the adjacent parking area to reach stormwater collection, treatment and management infrastructure. The Development Review Board shall consider the adequacy of the proposed landscaping to assure the establishment of a safe, convenient, and attractive parking area and the privacy and comfort of abutting properties. The applicant is proposing to reconfigure and add parking so that there are 66 parking spaces west of the building. Staff considers these standards apply to those 66 spaces. (1) All off-street parking areas shall be landscaped around the perimeter of the lot with trees, shrubs and other plants. Perimeter planting shall be set back from the curb sufficiently to allow for snow storage. The purpose of perimeter planting shall be to mitigate the view of the parking lot from the public way and from adjacent uses and properties, and to provide shade and canopy for the parking lot. In some situations it may be necessary, both for surveillance purposes and for the perception of safety, to install the size and type of plants that leave visual access between the parking lot to the public way or other pedestrian areas. The applicant has provided a revised planting plan which includes six shrubs which reach a mature height of 2.5 feet, and 26 grasses, concentrated around the three northern most parking spaces. During the hearing the applicant indicated that the parking area is below the existing roadway. The plans indicate the parking area is approximately 4-feet below the existing roadway. Staff considers the grade difference to be sufficient to mitigate headlights from the adjoining roadway. The purpose of providing shade and canopy for the parking lot is not met. There are shade trees planted on the far side of Davinci Drive relative to the project, which Staff considers will not provide shade to the parking lot. Shade trees are specifically discussed under (4) below. (2) In all parking areas containing twenty-eight (28) or more contiguous parking spaces and/or in parking lots with more than a single circulation lane, at least ten percent (10%) of the interior of the parking lot shall be landscaped islands planted with trees, shrubs and other plants. Such requirement shall not apply to structured parking or below- ground parking. As discussed on June 4, this standard applies to this project and compliance is computed by taking the square footage of the parking area and the square footage of landscaping islands contained therein. Staff has estimated this to the best of their ability and calculates that roughly 8% of the interior of the parking lot consists of landscaping islands, though no trees are provided. 4. Staff recommends the Board direct the applicant to reduce the parking area, increase the landscaping area, or both, to meet this criterion, and demonstrate compliance by providing a figure. (3) All interior and perimeter planting shall be protected by curbing unless specifically designed as a collection and treatment area for management of stormwater runoff as per 13.04(B)(5)(c) below. Interior planted islands shall have a minimum dimension of six (6) #SP-24-20 5 feet on any one side, and shall have a minimum square footage of sixty (60) square feet. Large islands are encouraged. No curbing is shown on the proposed plans, though the applicant stated that they are proposing curbing on the Davinci Drive side of the parking lot. They note the presence of a stone lined swale along the airport side of the parking lot as a reason to not provide parking. Though Staff can confirm that stormwater runoff would indeed flow to that side of the parking lot based on the provided grading plan, the submitted plans only show a stone lined swale for approximately 16 feet of the 800+ foot long parking lot. 5. Staff recommends the Board require the applicant to provide curbing along the parking lot except for the 16-feet of stone line channel, and along the drive aisle where the drive aisle is adjacent to the bioretention area for protection of the plantings included therein, as well as along the Davinci Drive side of the parking lot. This recommendation is supported by the comments of the City stormwater section, below. (4) Landscaping Requirements (a) Landscaping shall include a variety of trees, shrubs, grasses and ground covers. All planting shall be species hardy for the region and, if located in areas receiving road runoff or salt spray, shall be salt-tolerant. This criterion should be used in designing the proposed landscaping for the revised and expanded parking lot. Staff recommends the Board seek the feedback of the City Arborist on the revised parking lot landscaping when provided. (b) At least one (1) major deciduous shade tree shall be provided within or near the perimeter of each parking area, for every five (5) parking spaces. The trees shall be placed evenly throughout the parking lot to provide shade and reduce glare. Trees shall be placed a minimum of thirty (30) feet apart. (c) Trees shall have a caliper equal to or greater than two and one-half (2 ½) inches when measured on the tree stem, six (6) inches above the root ball. (d) Where more than ten (10) trees are installed, a mix of species is encouraged; the species should be grouped or located in a manner that reinforces the design and layout of the parking lot and the site. As noted about, shading is the second purpose for requiring parking lot perimeter planting. The applicant testified that they cannot provide additional perimeter plantings due to grading. Staff has calculated that the slopes between the parking area and Davinci Drive range from 12% to 60%. 6. 14 shade trees would be required for 66 parking spaces. Staff recommends the Board direct the applicant to provide at least some fraction of the required shade trees. (7) Snow storage areas must be specified and located in an area that minimizes the potential for erosion and contaminated runoff into any adjacent or nearby surface waters. 7. Snow storage areas have been specified. These snow storage areas are located on slopes as steep as 60% upwards away from the pavement. Staff considers it unlikely that a snow plow would be able to push snow up a 60% slope and recommends the Board require the applicant to modify the snow storage areas to include areas that are actually realistic for snow storage. C. Screening or buffering. The Development Review Board will require landscaping, fencing, land shaping and/or screening along property boundaries (lot lines) whenever it determines that #SP-24-20 6 a) two adjacent sites are dissimilar and should be screened or buffered from each other, or b) a property’s appearance should be improved, which property is covered excessively with pavement or structures or is otherwise insufficiently landscaped, or c) a commercial, industrial, and multi- family use abuts a residential district or institutional use, or (d) a parking or loading area is adjacent to or visible from a public street. (1) There shall be sufficient landscaping, walls, or fencing of sufficient height (minimum of three (3) feet) and opacity to effectively screen the parking or loading area year-round from adjacent public streets. (2) Screening of a parking or loading shall be provided where headlights from vehicles on site may be visible and project parallel to a public street. Staff considers the elevation of the parking area relative to Davinici Drive to adequately meet these two criteria. I. Landscape Maintenance. Maintenance and responsibility. All planting shown on an approved site plan shall be maintained by the property owner in a vigorous growing condition throughout the duration of the use. Plants not so maintained shall be replaced with new plants at the beginning of the next immediately following growing season. Trees with a caliper of less than 5” may be replaced on an inch-by-inch basis with trees of the same genus of at least 2” caliper each. No permit shall be required for such replacements provided they conform to the approved site plan. Replacement of trees with a caliper of greater than 5” shall require an amendment to the site plan. The applicant is proposing to remove four (4) 8 to 10-inch caliper trees from the front of the building. The applicant is now proposing to plant thirteen shrubs and 68 ornamental grasses. 8. Staff considers the proposed plantings to be insufficient replacement for the removed trees, as they do not provide the same screening, shading, or general aesthetic value. Staff recommends the Board discuss with the applicant how they will compensate for the proposed tree removal. 13.05 Stormwater Management Stormwater standards apply when one-half acre or more of impervious surface exists or is proposed to exist, and where 5,000 sf of impervious is created or reconstructed. The City Stormwater Section reviewed the plans on June 11, 2024 and offers the following comments. The Stormwater Division has reviewed the BSD Aviation Technical Center Site Plan Application provided by EIV Technical Services. Please note that several issues were identified that, once remedied, may have resulting implications for the stormwater design’s compliance with the City’s LDRs and will likely require additional review. We would like to offer the following comments: 1. General Application Comments: a. Please provide a stormwater maintenance plan. b. If the applicant is proposing the use of site balancing to meet the requirements of the LDRs, please provide a narrative description of said site balancing. 2. HydroCAD Modeling: a. 1-year storm: Peak discharge at CB#2 under the proposed conditions exceeds the existing conditions peak discharge at CB#2. As per the LDRs Section 13.05.E.2, “The post-construction peak runoff rate for the one-year, twenty-four hour (rainfall amounts to be determined using NOAA, Atlas 14 data and a type II rainfall #SP-24-20 7 distribution) rain event shall not exceed the existing peak runoff rate for the same storm event from the site under conditions existing prior to submittal of an application.” Please revise design to comply with the LDRs. b. 25-year storm: Model indicates surcharging occurring at CB#2 under the proposed conditions. As per the LDRs Section 13.05.F.3, please revise design to ensure downstream structures retain capacity to convey the 25-year storm. c. The biorentention calls out a 1.0 in/hr discarded exfiltration, but also calls out 2.0 in/hr exfiltration routed to the outlet structure through an underdrain. Please provide justification for the discarded exfiltration modeling decision. d. Pre-treatment forebay: please provide sizing information for the forebay, ensuring that it meets the sizing requirements laid out in the Vermont Stormwater Management Manual (VSMM). 3. Sheet GR-01: a. Grading in the pervious (grassed) areas is inadequate to determine flow path of stormwater. Please provide details of how applicant will ensure all stormwater draining from the impervious area in Sub-catchment #2 will enter the bioretention via the pre-treatment forebay. b. Please provide information on how the applicant will prevent stormwater from creating a ponded area in the vicinity, both on and off the pavement, of the 312’ contour on the section of pavement connecting the two parking wings. Please note that there is an existing light pole to remain directly adjacent to this area. Grading information is inadequate to determine the extent of the ponding that may occur. c. Please indicate the elevation at the edge of the bioretention area on the plan. d. Staff recommends the applicant add curbing along the parking area to ensure all stormwater flows to the treatment area and enters via the pre-treatment forebay. 4. Sheet P-01: a. The delineation for Sub-catchment Area #2 does not appear to match the routing in the HydroCAD model. Please explain how runoff from the new impervious in the western corner of Sub-catchment Area #2 is being conveyed to the proposed bioretention area. b. Is site balancing being proposed to meet treatment requirements for the section of new impervious in Sub-catchment Area #1? If so, please indicate on the plan the size of the new area and the corresponding area in Sub-catchment Area #2 that will be used for site balancing. 5. Sheet MD-03: a. Please clarify the following in the bioretention basin detail: i. There is an underdrain shown, but the basin is called out as an “infiltration basin”. Please clarify whether or not this is an infiltrating bioretention practice. ii. The “Temporary/Permanent Sediment Forebay/Basin” callout. Please clarify which of these options is shown here. iii. Please clarify whether or not the outlet structure is meant to comply with the “Drainage Structure” detail on this same sheet. If not, please provide details of the outlet structure. #SP-24-20 8 6. EPSC: Please consider using the footprint of the bioretention area as a temporary sediment basin during construction. 9. Because of the extensive nature of the comments of the City Stormwater Section, Staff recommends the Board continue the hearing to allow these comments to be addressed. 13.07 Exterior Lighting Lighting requirements are summarized as follows. (1) Fixtures must be downcast and shielded (2) Illumination must be evenly distributed (3) Fixtures must be placed to minimize lighting from becoming a nuisance (4) Poles shall be rustproof metal, cast iron, fiberglass, finished wood or similar structural material, with a decorative surface or finish (5) Poles & building mounted fixtures may be no higher than 30-ft (6) Poles must be located in safe locations Specific requirements for maximum illumination levels are included in Appendix A and are limited to 3-foot candles average at ground level. The applicant has provided a photometric drawing but has not indicated an average illumination level, though Staff considers it is likely to be below 3 foot candles. The applicant has modified the previously submitted plan to remove the “hotspot” of 15 footcandles near the eastern entrance of the building. Illumination levels are now no greater than 9 footcandles. Staff considers lighting requirements to be met. 13.12 Utility Cabinets and Similar Structures B. Specific Standards for Utility Cabinets and Similar Structures. (4) There shall be sufficient landscaping or fencing of sufficient height and opacity to screen effectively the facility year-round from streets and abutting unaffiliated properties. 10. The applicant testified that the generator is proposed to be 8 – 9 ft high, and the transformer is 5 – 6 ft high. The applicant further testified that the proposed plantings will only partially screen the equipment. Staff recommends the Board require the applicant to provide screening of sufficient height to screen the transformer from the street. (5) The location of the facility shall be shown on all relevant site plans. (6) Utility cabinets and similar structures shall be located a minimum of five (5) feet from all existing or planned public roads or rights-of-way. Staff considers criterion #5 and 6 to be met. RECOMMENDATION Staff recommends that the Board work with the applicant to address the issues identified herein.