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HomeMy WebLinkAboutGorsuch Haus Project Review_Engineering Comments 2019.08.121 Memorandum From: Hailey Guglielmo City of Aspen Engineering Department To: Jesse Swann, Richard Shaw, Carly Klein, Jean Coulter Date: August 12, 2019 RE: Gorsuch Haus DRC Engineering Comments Update The following are remaining large items to be resolved and require direction from the City. 1. Infrastructure in the ROW – a. The project proposes the transformer and switchgear be located in the ROW below the retaining wall. i. City Standards require all above grade infrastructure be located within property boundaries. A variance for this standard will not be granted in this location. The transformer and switchgear need to be located within the property. b. The project proposes a retaining wall 14’ in height be located in the ROW. This item requires a variance. i. The retaining wall provides a public benefit as it allows for the construction of the cul-de-sac and pedestrian walkways on an otherwise dead end road. For this reason, the retaining wall will be permitted in the ROW. The wall should be designed in a way to limit visual impact and damage to existing trees. Final design needs approval from the Engineering and Community Development Departments. ii. The walkway below the retaining wall shall provide 6’ of clear space with trees in an appropriately sized buffer. Silva Cells shall be installed below the walkway. c. The project proposes a swale and new drainage inlet further up the mountain in the ROW. This requires the removal of the trees. i. The swale and inlet are permitted in the City ROW as they are public infrastructure providing a public benefit to collect drainage. ii. There is concern about the accessibility of the swale and inlet for maintenance. Is the intent to drive around the building to access the inlet? Due to the unusual difficulty to access, the inlet will require a revocable encroachment license and will be the responsibility of the Gorsuch Haus to maintain. Additionally, an easement shall be provided up the summer road and around the building in the event the city needs access the swale and inlet. iii. Tree removal will require Parks approval. 2. Snowmelted Cul-de-sac a. Ordinance 39 of 2016 specifies the process for determining snowmelt along all of South Aspen St. The cul-de-sac is a component of the street and the process for determining the use of snowmelt shall follow what was written in Section 30 of Ordinance 39. There is still the possibility of snowmelting all of South Aspen Street. 2 b. REMP fees or any exemption will need to be worked out and finalized with Community Development and possibly council. Ordinance 39 Section 30 (H) speaks to REMP fees for South Aspen Street. c. If just the cul-de-sac and not the whole street is snowmelted, snow plows will use the cul- de-sac to turn around. The plows have chains on the tires that will damage a concrete cul- de-sac. Damage to snowmelted concrete will have additional costs to maintain. The maintenance and replacement will be the responsibility of the Gorsuch Haus. The City will not be responsible for damage incurred by Street maintenance. d. If just the cul-de-sac and not the whole street is snow melted there is still concern of ice damning and trench drain placement at the edge of the snowmelt. i. The Engineering Department would like to see as much drainage as possible given the grading be directed into the center landscape island. Inlets may be placed in the center island. This would provide a water quality benefit as well. ii. For the remaining area that doesn’t drain to the center island, we need more research on the best option to avoid ice damning where the snowmelt ends. There is concern a trench drain placed in this location will be destroyed by the snow plows and graters. Below are some brainstorming ideas that should be vetted. 1. Look more into trench drain types and provide a spec to the Engineering department. Snowmass has a trench drain at the bottom of Snowmelt Road but I do not think plows go over the trench drain. Before a trench drain is approved int eh ROW the Engineering Dept needs proof of it’s durability and examples of where it has lasted in other areas. 2. Look in to a possibility of a shallow valley pan. Given the steep road I’m not sure how effective a pan would be, but it should be vetted. Perhaps put the pan at an angle. 3. Look in to grooves in the pavement at an angle. Similar to the idea of the groves in the gutter at the rain gardens at the art museum. 4. Place additional inlets and construct a pronounced crown. Documents to be submitted with Final PUD. 1. Slope stability analysis. For submittal to Colorado Geological Survey 2. Finalized Mudflow Report 3. Updated Transportation Impact Analysis which shows all vehicle trips are mitigated with programs or infrastructure that support alternative transportation. 4. Traffic Study from LSC which shows the cul-de-sac and two loading spots can support the expected lodge traffic. 5. All easements shown on the plat that have been discussed. The comments below are an update to the original DRC comments dated October 5, 2018. The following summarizes discussions and updates from the project team over the past year. The October 8th DRC comment letter was in regard to the September 4th, 2018 DRC submittal. Previous Engineering memorandums for the initial 2016 submittal are dated May19, 2016 and October 14, 2016 Blue lettering indicates the issue has been addressed and is no longer relevant. 3 Black Lettering indicates the issue remains to be resolved and the description gives a timeline at what step in the process this information should be finalized. S Aspen St ROW Vacation: The ROW vacation was approved to move forward through Council and the public vote. This comment is no longer applicable. Easements: 1. 10/5/18 - Dedication Number 5 - The Engineering Department supports an increase in public access easements through the site. Pedestrian and bicycle access should be provided for access up the mountain road. The current proposed dedication only provides access for Lot 1. a. 8/12/19 – Ensure the plat shows all easements discussed in the 10/31/18 response and language has public access and not just access for Lot 1. 2. 10/5/18 - Follow the utility easements dimensions found in section 2.5.2 of the Engineering Design Standards. All rear and side lot lines shall have a 5’ utility easement. a. 8/12/19 – Utility easements will be reviewed with the plat submittal. 3. 10/5/18 - Provide easements for any required mud or debris walls. a. 8/12/19 – This will be finalized with the submittal of the finalized mudflow report and plat with easement. 4. 10/5/18 - Drainage easements need to incorporate channel flow, not just areas where stormwater infrastructure is proposed. a. 8/12/19 – This will be finalized with the submittal of the finalized mudflow report and plat. The 10/31/18 response stated no easement is required, but preliminary grading plans have shown swales and above grade drainage components. 5. 10/5/18 - Gorsuch Haus will need permission from Mountain Queen to change their drainage and access easement. Maintenance of an open channel is very different than maintenance of a road with pipe. a. 8/12/19 – To be finalized with agreements with Mountain Queen. Agreements need to be in place and shown on finalized plat. Utilities: 6. 10/5/18 - All trees shall be planted a minimum of 10’ away from existing and proposed utilities. a. 8/12/19 – Will be shown in PUD. 7. 10/5/18 - Fire flow calculations shall be submitted at building permit to demonstrate an 8” line is necessary. Calculations for a 6” line shall also be submitted which show the 6” line does not supply adequate fire sprinkler protection. a. 8/12/19 – To be completed prior to Building Permit. 8. How will access to the utilities and drainage infrastructure on the west side of the property be achieved? This includes the offsite headwall and catch basin, the existing switchgear, transformer serving Shadow Mountain, and the proposed transformers on the Gorsuch property? The proposed retaining wall by the cul-de-sac cuts off that access and access around the structure doesn’t seem feasible either. The City requires access to the public infrastructure for maintenance. a. 8/12/19 – The transformer and switchgear are now proposed down by the cul-de-sac below the retaining wall. They are accessible but they are in the ROW and a variance will not be granted to place above grade infrastructure in the ROW. An alternative spot for the transformer and switchgear needs to be proposed. The issue of access to the inlet and swale remains to be addressed. 4 b. Also, project needs to verify the Shadow Mountain Townhomes transformer and utility pedestals located at the top of their property will still be accessible with the new road configuration. Mudflow and Debris Flow 9. 10/5/18 - What’s the plan with the plan? No improvements are shown for mitigation. This still needs to be worked out to a level where we can be confident the site plan is not going to change to a degree that would require the project to go back to P&Z or council. a. 8/12/19 – A finalized mudflow report needs to be submitted to the Engineering Department and any mitigation infrastructure and required easements. This shall be completed prior to PUD and plat. Street Maintenance and Snowmelt – 10. 10/5/18 - The City is unable to maintain SAS at the level of service needed for these lodges. The cost sharing agreement recommends upgraded maintenance equipment as the most feasible option to maintain safety on the street. It is not clear what the upgraded equipment is, or if it will be sufficient. There is no higher maintenance that the City can provide to maintain South Aspen St to a level that is required for the proposed level of use. More sand is not a viable solution. The onetime payment from the developments will not cover the unending maintenance required. The city recommends snowmelt or the creation of a maintenance district so that the lodges maintain the roadway instead of the City. There are also environmental impacts to not snowmelting. These include the use of deicers and the resulting pollution added to the Roaring Fork River. a. 8/12/19 –Section 30 of Ordinance 39 outlines the process for determining the need for snowmelt on South Aspen Street. 11. Snow Storage - The property needs to accommodate snow storage, both onsite and for the cul-de- sac. A minimum functional area equaling 30% of the paved area shall be provided contiguous to the paved area and designed to accommodate snow storage (unheated areas). For heated areas, the functional area can be reduced to 10%. a. 8/12/19- The project proposes snowmelting the cul-de-sac. This will be worked through following Item number 2 of the first section of this memo. Stormwater/Drainage 12. 10/5/18 - In the current application there is no indication on how stormwater or drainage will be handled onsite. The project will be responsible to follow all URMP requirements. From conversations the Engineering Dept believes this can be accomplished with the proposed site plan. a. 8/12/19 – The latest schematic shows all stormwater being handled in onsite vaults. The conceptual master drainage plan is headed in the right direction, and shall be reviewed in full with the submittal of the PUD and plat. TIA: 8/12/19 – An updated TIA plan shall be submitted to the Engineering Dept prior to the final PUD. Below are the 2018 comments and the project falls short of the required mitigation points. 13. Measure number 9, large scale landscaping, is not applicable. The project will remove a handful of large trees. The loss of this established vegetation nullifies this measure. 5 14. Measure Number 15, pedestrian interaction with vehicles, is not applicable. The project does greatly improve the interaction with the parking area, however the project proposes vehicle access to the Mountain Access Road to pass through a pedestrian area. This is a detriment to the pedestrian experience and nullifies this measure. 15. The TIA takes credit for a full bus stop with a bench, shelter, and lighting. This measure is meant for a City bus stop. A bus or shuttle stop is not proposed at the cul-de-sac, all public access to the lift will be down on Dean St. Therefore, measures 28, 29, 31, and 32 are not applicable. 16. With the removal of the above measures the project is 22 points short of the required mitigation. The project shall consider other measures that will improve pedestrian, bicycle, and transit options. 17. A plan drawing which shows all MMLOS improvements is needed. Stability: 18. 10/5/18 - A slope stability study is required as slopes on and above the site exceed 30%. This study will be forwarded to the Colorado Geological Survey for review. The review fees will be invoiced to the applicant directly. a. 8/12/19 – The response to comments states a soils stability report has been completed. Please submit the report to the Engineering Dept prior to final PUD. Earth Retention: 19. 10/5/18 - Inclinometers will be required prior to and during construction to monitor ground movement. Below is wording from South Aspen St PUD that shall be included in the Gorsuch Haus PUD. a. Ground Stability Monitoring. In order to ensure that development of the Project does not exacerbate naturally occurring ground movement, an inclinometer shall be installed and maintained by Gorsuch Haus or its successors or assigns with bi- annual readings taken through the time of issuance of a Certificate of Occupancy. The first Building Permit application for the Project shall include a report on the initial readings and a subsequent report is required prior to issuance of a Certificate of Occupancy. b. 8/12/19 – Will be finalized in PUD review. Streets and Sidewalks/Cost Recovery: 1. 10/5/18 - The property is required to reimburse One Aspen for a pro-rata share of costs associated with the reconstruction of South Aspen St and associated sidewalks, public utilities, and drainage facilities. Reimbursement shall take place prior to issuance of a building permit per Lift One Lodge Subdivision Agreement Sections 3.3-3.5. a. 8/12/19 – To be completed at building permit. Additional Comments: 20. More information is needed on grading to understand the extents of grade changes and retaining walls onsite. Particularly the following. a. How tall is the proposed retaining wall on the west side? i. 8/12/19 Response to comments state 16’ at it’s highest. This wall is in the ROW and requires a variance for its placement. Due to the public benefit the retaining wall provides for the cul-de-sac and pedestrian walkway. The variance will be 6 granted. The wall should be designed to limit visual impacts. A good example is the alley on Mill St below Bleeker St. Final design will be reviewed by Engineering and Com Dev. b. Along the Hill St corridor there are two curbs. How is access provided up the Mountain Access Road? How is ADA access provided with the second curb? i. 8/12/19 - A conceptual plan has been submitted that shows ADA access around the cul-de-sac. c. What is the grade change on the north side to the Lift One Lodge property? Given the existing topography will this be a retaining wall with what height and what fall protection given it is a pedestrian area? i. 8/12/19 – the response to comments is a guardrail and fall protection will be provided. This has been addressed. d. The existing slope on the SW corner of Lift One Lodge property does not provide ADA access. How will ADA access be provided? i. 8/12/19 - A conceptual plan for an ADA route has been presented and is acceptable at this time. e. The crossings to Shadow Mountain Townhomes and the garage entrance must have ADA crossings. i. 8/12/19 - A conceptual plan for an ADA route has been presented and is acceptable at this time. 21. 10/5/18 - The Lift One Lodge and South Aspen Street PUDs required public parking spaces be provided at the top of South Aspen St. Where are these now accommodated? a. 8/12/19 - Gorsuch response said the 50 public spots in the LOL garage will cover the four lost. The site plan was approved by council and the public vote. This comment is no longer relevant. 22. 10/5/18 - The loading area provides two parking spaces. There is still concern of the cul-de-sac becoming congested and limiting emergency access through. Are two spots adequate for a hotel of this size? How will the drive area be kept clear? a. 8/12/19 – LSC completed a traffic study which concluded the two spots are adequate. Please provide the LSC report to the Engineering Department. 23. 10/5/18 - The first catch basin up Mountain Access Road, near the Mountain Queen, appears to be in conflict with an existing waterline. Is adequate separation provided? a. 8/12/19 - Will be further evaluated with the PUD submission.