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20190604_response letter.pdf PO Box 1478 ⬧ Everett, WA 98206 ⬧ Phone: (425) 303-9363 Fax: (425) 303-9362 ⬧ Email:info@insightengineering.net May 23, 2019 Karen Lien 3000 Rockefeller Ave. Everett, WA 98201 (425) 388-3311 Re: Langford – PLN20180064 IECO No. 19-0992 Dear Karen, The project referenced above is revised in response to the review comments dated December 6, 2018. The review comments are numbered on the letter and have been addressed in italics as follows: 1. Geotechnical Report: The critical area determination conducted on 1136 Vista Place under file number CRA20180201 identified slopes on the site that exceed 40% which are considered potential landslide hazard areas pursuant to Chapter 23.80 ECDC. A geotechnical report consistent with requirements of ECDC 23.80.050 and addressing the specific requirements ECDC 23.80.060 and .070 must be prepared to evaluate the potential impacts of the proposed subdivision. Please also see the comments under Subdivision Review Criteria below which will relate to the development and review of the geotechnical report. Please see the submitted Geotech report included with this submittal. 2. Wetland Determination: The critical area review under file number CRA20180201 also identified an off-site wetland that may have buffers that extend onto the subject property. In 2016 a wetland report was submitted for a project located at 1142 Vista Place. The wetland was determined to be a Category III wetland. Wetland buffers for Category III wetlands range from 60 feet to 225 feet depending on habitat score. The wetland rating system has changed since the 2016 report was prepared so the extent of the buffers cannot be determined; however, given the potential for a 225 buffer and the wetlands location shown at 96 feet from the property boundary, the wetlands buffers may extend onto the subject property. I have included the old wetland report regarding this wetland for your reference. It must be determined whether the buffers from this wetland extend onto the subject property. Understanding that the wetland is on adjacent property and access to the wetland will rely on the adjacent property owner granting access for a PO Box 1478 ⬧ Everett, WA 98206 ⬧ Phone: (425) 303-9363 Fax: (425) 303-9362 ⬧ Email:info@insightengineering.net determination, there may be other options regarding the impacts of this wetland. First, I would suggest contacting the adjacent property owner to see they will grant access. If not, perhaps the old wetland report can be updated using the current wetland rating form to determine the habitat score and thus the associated buffer width. Finally, depending on whether the private drive needs widening (see fire comments below) the developable portion of the site may be in an interrupted buffer. The interrupted buffer determination consistent with the requirements of ECDC 23.40.220.C.4 would have to be approved. Please submit an updated wetland report or, if appropriate, an interrupted buffer determination. A wetland evaluation report is included with this submittal. 3. Easements: The title report identifies a number of access and utility easements on the subject property. Please provide these easements which are identified by the following auditor file numbers (AFN) in the title report: 815306, 1126222, 1625989, and 1444635. Additionally, the location of these easements and any other easements on the subject property must be identified on the preliminary short plat. The easements have been shown and labeled with their AFNs. 4. Preliminary Short Plat: a. Surveyor signature – ECDC 20.75.040 requires the preliminary short plat to be signed by the surveyor and preliminary short plat submitted with the application was not signed by the surveyor. Please submit a preliminary short plat signed by the surveyor. Please see the signed preliminary short plat map. b. Gross and Net Lot Area – Identify the gross and net lot area of each of the proposed lots. Note that any access easement must be subtracted from the gross lot area and the resulting net lot area must be at 12,000 square feet. The gross and net areas have been outlined in the new short plat. c. Please identify all structures within 25 feet of the subject property as required by ECDC 20.75.060.M. Any structures within 25 feet of the property line have been shown. 5. Site Bench Mark: The topography survey submitted with the application indicates the site benchmark is a nail in the asphalt as shown with an elevation of 349.9. The site benchmark identified in the survey notes an elevation of 280.1. Please verify the site benchmark and associated elevation. PO Box 1478 ⬧ Everett, WA 98206 ⬧ Phone: (425) 303-9363 Fax: (425) 303-9362 ⬧ Email:info@insightengineering.net 6. Subdivision Review Criteria: The criteria for reviewing subdivisions is contained in ECDC 20.75.085. On initial review, more documentation is needed to demonstrate that the criteria below can be met: a. ECDC 20.75.080.A.4 Where conditions exist which could be hazardous to the future residents of the land to be divided, or to nearby residents or property, such as floodplains, steep slopes or unstable soil or geologic conditions, a subdivision of the hazardous land shall be denied unless the condition can be permanently corrected, consistent with subsections (A)(1) and (2) of this section. Almost all of the proposed Lot 1 consists of slopes in excess of 50%. Developing this site may require a significant cut into the hillside which could impact slope stability and existing residence on the top of the slope. The geotechnical report must address how this site could be developed and how the hazard can be permanently corrected. As noted in the Building Division comments (attached), it is likely that peer review will be required for the geotechnical analysis and design. Note the cost peer review is required to be covered by the applicant. Please see the included geotechnical report. b. ECDC 20.75.080.B.1 Lots shall be designed to contain a usable building area. If the building area would be difficult to develop, the lot shall be redesigned or eliminated, unless special conditions can be imposed on the approval which will ensure that the lot is developed properly. In addition to the slopes on the proposed Lot 1, the orientation of Lot 1 with the private drive that transects the lot further limits the buildable area and makes this a difficult site to develop. The proposed residence for Lot 1 shown on the preliminary development does not comply with the setbacks for Lot 1. A lot cannot be created through the subdivision process that would require a variance in order for it to be developed. The setbacks have been corrected on the revised plan. Different layouts for subdividing this property were presented during the two pre- application style meetings over the last year. Given the review criteria in ECDC 20.75.080A.4 and 20.75.080.B.1, a different layout of the proposed subdivision should be given strong consideration. Otherwise, please demonstrate how the proposed layout complies with these criteria. The layout has been changed. Lot 2 is now much larger, and has a larger portion on the southeast corner of the site. It should be noted that an 80-foot lot circle can fit onto it. There are technically now two buildable pads on Lot 2, one in the east and one in the west. While the west is still where the client wishes to build, there is also a possibility of building elsewhere. PO Box 1478 ⬧ Everett, WA 98206 ⬧ Phone: (425) 303-9363 Fax: (425) 303-9362 ⬧ Email:info@insightengineering.net 7. Fire Comments: The proposal was review by South Snohomish County Fire District; whose comments are attached. The Fire District notes that the private drive would serve three lots following this subdivision. If the private drive is to serve three lots, it would need to be widened to 20 feet and a fire department turnaround provided. Alternatively, in place of a 20-foot wide drive, a second gate could be installed which would prevent Lot 1 from access via Vista Place from the Olympic Avenue side. Both gates (including the existing one on the 12th Avenue side of the property) would need to be equipped with a key switch and Opticom sensors. The existing home will now not be served by the private drive, and will instead only access from 12th Ave. The new lot will not have access to 12th Ave. Therefore, the existing easement should be sufficient for the new lot and the existing lot to the south which would share access with it. 8. Please respond to the comments from Jeanie McConnell, Engineering Program Manager, provided in the attached memorandum. If you have any questions on Ms. McConnell’s comments, you may contact her. See below. Memorandum from Jeanie McConnell, Engineering Program Manager December 6, 2018 GENERAL 1. Provide a site plan that shows access point from Vista Place and 12th Ave N. The access points have been labeled. 2. Label roads as private or public right-of-way (ROW) and provide dimensions for ROW and/or easement areas. These specifications have been provided on the plat map for both Vista Place and 12th Ave N. 3. Label existing pavement width of Vista Place adjacent to the subject property, as well as the existing pavement width of that section or ROW that provides a connection between the subject property and 12th Ave N. The pavement has been added and the widths have been labeled. 4. Show existing access easement areas and existing pavement areas on one plan sheet. Will the existing and proposed pavement areas fall within existing easement areas? The pavement areas have now been shown, as well as the easements. PO Box 1478 ⬧ Everett, WA 98206 ⬧ Phone: (425) 303-9363 Fax: (425) 303-9362 ⬧ Email:info@insightengineering.net 5. From the plans provided it looks as though the existing driveway that loops from Vista Place to 12th Ave N will remain. Please confirm and refer to South Snohomish County Fire District comments. The driveway is no longer to remain as-is—some of it will be removed to prevent access to 12th Ave N. 6. Refer to South Snohomish County Fire District comments for access width requirements. Comment noted. UTILITIES 1. Show the location of stormwater systems, sanitary sewer systems, water mains, water meters, and water service lines adjacent to or within the proposed subdivision. Utilities to the existing and proposed homes shall be shown. Provide approximate invert elevations for side sewer at house, property line and new connection to main to show feasibility. Call out length and size of all pipe to verify slopes. Please see the revised plan. 2. If a fire sprinkler system is required for the proposed single-family residence, the water service to the property will need to be larger than what’s proposed. Typically, a 1” meter and 1 ½” water service line provides sufficient flow. Revise plans accordingly. Please see the revised plan. 3. Show the location of existing and proposed dry utilities within the subject site. All new services shall be installed underground. Please see the revised plan. Comments from Zack Richardson, PE, Stormwater Engineer November 30, 2018 Review comments: 1. Drainage Report: In 5.4, expand text to more clearly explain that “mitigate (801)” represents the combined flows (ie. vault overflow plus bypass). The report and method of stormwater disposal has changed. Please see the new report. 2. Drainage Report: No action required at this time, but omission of the downstream analysis (as stated in 6.1.3) is only permitted if the report continues to show that the combined discharge will be less than existing condition; future revisions shall maintain this condition or the analysis will be required. Please see the new report. We are proposing infiltration for all new impervious areas. PO Box 1478 ⬧ Everett, WA 98206 ⬧ Phone: (425) 303-9363 Fax: (425) 303-9362 ⬧ Email:info@insightengineering.net 3. Drainage Report: In the first paragraph of 6.5, please remove the term “earth subsidence”. a. The earth subsidence and landslide hazard area (ESHLA) is a specific area of Edmonds in which this project is not located; the site contains only a (more typical) landslide and erosion hazard areas. Please see the new drainage report. b. Keep in mind that the construction of retaining walls may eliminate small localized landslide hazards and may not still be applicable as an infeasibility criteria for LID BMPs after the project completion; include geotechnical evaluation or report text to address the size and scope of the landslide hazard and/or changes to the landslide condition as a result of the proposed project. Please see the revised geotechnical report. 4. Drainage Report: Section 6.5 references a section of the ECDC 18.30 which cannot be identified, update reference as needed. It is believed that the reference is intended to be 18.30.06.D.5.b.v.b.i, however that section is only applicable to projects which do not discharge to the City’s MS4 and does not appear applicable to this project (18.30.06.D.b.v). Not applicable, as the report has changed. 5. Drainage Report: Update the MR#5 section to list specific infeasibility criteria for each BMP, working in order down the BMP list. a. A geotechnical report is likely still required in order to determine all BMPs infeasible; include geotechnical report with next submittal. Please see the infeasibility table shown in Appendix A of the drainage report. 6. Drainage Report: It is unclear why the orifice elevation is -0.0416’ in the WWHM model; adjust to zero or clarify as needed. The detention system has been removed so this comment is no longer valid. 7. C5: Per SWMMWW III-3.2.3.Access.8, the minimum height of detention vault shall be 7’, which exceeds the current depth proposed; revise detention design or product-type (ie. detention tank; see Edmonds Addendum 6.3 for additional guidance) as needed. The detention system has been removed so this comment is no longer valid. 8. C5: It appears the current proposal may not meet SWWMM recommended setback requirements for the vault (property line, structure, and steep slope); update plan or include additional text in drainage report as needed to address setbacks from the vault. PO Box 1478 ⬧ Everett, WA 98206 ⬧ Phone: (425) 303-9363 Fax: (425) 303-9362 ⬧ Email:info@insightengineering.net The detention system has been removed so this comment is no longer valid. Memorandum from Leif Bjorback, Building Official December 3, 2018 1. Building permits will be required for the following, as applicable: New home construction; retaining walls; modifications to or demolition of existing structures. Comment noted. 2. Dwellings exceeding 3000 square feet of fire area require fire sprinklers. Comment noted. 3. Park Impact fees will be assessed for each new dwelling at a rate of $2734.05 each. The fee may be waived for new homes that replace old homes provided the new construction occurs within one year of the demolition of the old structure. Comment noted. 4. The topography of proposed Lot 1 contains slopes in excess of 50% and, given the dimensions and orientation of the lot, appears to be a difficult site to develop. Excavations, foundation design and related site work will be required to be based on a geotechnical analysis. It is highly likely that temporary shoring will be required, and slopes excavation cuts will be limited to generally accepted engineering practices. It is also likely that peer review will be required for the geotechnical analysis and design. Okay, the owner understands additional geotechnical work will be needed to develop the lot. Comments from Karl Fitterer, Assistant Fire Marshal November 29, 2018 Private drive services 3 or more residents would need a fire department turnaround and driveway would need to be 20 feet wide. In place of 20 foot wide drive a second gate would need to be installed and both gates would need to be equipped with a key switch and Opticom sensors. This would enable the drive to be at Edmond’s City standards (12 feet paved). Also, will need signs placed at 50 foot intervals stating “NO PARKING FIRE LANE” along private drive. As the private drive would only serve 2 lots, the widening should no longer be necessary. Please feel free to contact me with any questions or comments you may have. Sincerely, Brian Kalab, P.E.