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09.26.12-Swedish Response Comments.pdf1221 Second Avenue t. 206.384.6000 Suite 200 f. 206.441,4981 Seattle, WA 98102 www.perkinswill,com September 26, 2012 Jeanie McConnell Engineering Program Manager City of Edmonds 121 5th Avenue N. Edmonds, WA 98020 RE: Plan Review Comments - Engineering Division Dear Ms. McConnell, Attached are the responses to your Permit correction letter dated September 11, 2012. Respectfully, Brad Hinthorne, AIA Perkins+ Wil[ NORTH AMERICA I ASIA I MIDDLE EAST I AFRICA I EUROPE a _ E � r 1) SEP 2 6 &12 BUILDING G 0 *AR<,TVIMN? Cl -r! OF EO NDS CITY OF EDMONDS Response to PLAN REVIEW COMMENTS ENGINEERING DIVISION DATE: September 26, 2012 TO: Jeanie McConnell, Engineering Program Manager FROM: Wade Watkinson, P.E. (NV) 206-926-0661 RE: Application #: bld20120661 Project: Swedish Medical Center Project Address: 21704 Highway 99 Responses to the Plan Review Comments received on September 11, 2012 are below each comment in bold and italics. If you have questions regarding these responses, please call me at 206-926- 0661. GENERAL 1. Please provide an itemized engineers cost estimate, including units and unit prices, for both on-site and off-site (right-of-way) improvements, including traffic control. The City recommends use of the King County Site Improvement Bond Quantity Worksheet. • A bond is required to be placed for all right-of-way improvements. The amount of the bond will be based on 120% of the City approved estimate for all right-of-way improvements. The City will inform you of the appropriate bond amount after review of the cost estimate. Bond forms can be obtained from Marie Harrison, Permit Coordinator — 425-771-0220 or Harrison@ci. edmonds.wa.us • Inspection fees for this project will be calculated at 2.2% of the 120% City approved estimate for all improvements. As inspection fees were paid under the previous permit and some but not all of the improvements were installed, it will be necessary for you to clearly outline this with your submittal so it can be determined what additional inspection fees are due. The bond estimate was submitted with the previous submittal, per the .Ding County form. A revised copy of this worksheet will be submitted with this revision and is attached. 2, A right-of-way construction permit was issued in conjunction with the previous building permit for the temporary curb cut on Highway 99 and restoration of such. This permit was issued to Skanska USA Building Inc. and is set to expire December 5, 2012. It appears as though Skanska is still the general contractor for the project, in which case we can work with you on the permit expiration. If there will be a new contractor then a new permit will need to be issued. Skanska is the current Contractor for this project. 3. Submit a traffic control plan for utility connections on Hwy 99. Traffic control plan has been provided by the Contractor and is shown on Sheet C-110 for reference, please refer to revised flan. Response t® PLAN REVIEW COMMENTS ENGINEERING DIVISION 4. 1 did not find storm detention vault structural talcs in the submittal. Were they submitted? If not, please submit for review and approval. The vault may be sent out for peer review. Detention Vault structural talcs will be performed by the manufacturer and submitted to COE for review. Review of the Drainage Report dated August 2012 was completed by Stormwater Engineer Jerry Shuster. If you have specific questions regarding these comments please contact Jerry directly by phone at 425-771-0220 or by email at jeny.shuster@edmondswa.gov GENERAL 1. Indicate which parts of the stormwater system installed under the previous permit will be "reused" in the design (if any). Conversely, indicate what parts constructed under the previous permit will be demolished with this project. No portions of the stormwater system previously permitted will be used with the revised system. The pipe that outfalls into the existing detention pond will be demolished, while upstream storm drain pipes will be retained for future use by Swedish. The existing flow control structure and corresponding inlet and outlet pipes will be used temporarily for sedimentation until phasing requires demolition of those facilities. The existing detention pond, outlet structure and all corresponding improvements will be demolish and replaced with an underground detention/wet vault system. 2. Provide a figure that shows the delineation of subbasins within the project site that flow to each stormwater facility (raingarden, vaults & ponds) and the amount of impervious and pervious area post -development. This should include tributary areas to the existing storinwater systems on the Swedish site. These were provided in Appendix D (Figures 1-3) in the Drainage Report dated November 2011 for the previous incarnation of this project. Update the figures to reflect the new. proposed project. A Basin Map has been included with the revised Drainage Report. Page 4 — Runoff Treatment 1. The discussion of runoff treatment should follow the procedure in Appendix 1, Section 4.6, of the Western Washington Phase 11 Municipal Stormwater Permit. The discussion should include an evaluation for need for oil control and enhanced treatment. Also, add a sentence that states that since the water quality treatment facility is downstream of the detention vault, it was designed to the full 2 - year release rate from the detention facility. The discussion of runoff treatment in the Report has been revised to cover all treatment requirements and exemptions. 2. The existing detention vault behind the proposed building was installed in 1999. The approved drawings for that vault show 150 lineal feet ofbio swale (1.5 ft wide @ 3.5%) along the north ENGINEERING DIVISION property line at the east end of the site. This bioswale is the approved water quality element for this detention system. The current set of drawings does not show this bioswale and it unclear fiom the drawings where the discharge from this 1999 vault day lights. The design must include this original bioswale or an approved equivalent alternate means of treating the discharge from the 1999 vault. The existing detention vault to the west of the proposed site is fed into a biofiltration Swale that is measured on the topographic survey at 135 lineal feet and 1.5 feet wide. The Swale was installed at an average slope of approximately 2.5%. The plans and the Report have been revised to incorporate a 90 lineal foot biofiltration Swale at 1.5% slope and 6 % feet wide. This width and length was determined to be hydraulically equivalent to the existing swale with respect to capacity and residence time. These calculations have been addressed in the Report and included as reference in Appendix D. Page 5 -- Flow Control 1. The site is a Large Site Project subject to the requirements in Appendix I, Section 4.6, of the Western Washington Phase 11 Municipal Stormwater Permit. The predevelopment condition for the entire site should be the forested condition (including "Landscape Pond Basins") and the criteria for compliance is the Standard Flow Control Requirement in Appendix 1, Section 4.7 of the Western Washington Phase 11 Municipal Stormwater Permit. The entire site is one threshold discharge area with a point of compliance at the northeast corner. There are several options for modeling the landscape/pond areas located east and south of the proposed parking area such as: a. Keep the ponds, but size them using the predevelopment condition as "forested" and post development condition as "lawn" for their subbasin areas. The ponds must be sized to meet the Ecology duration standard. b. Remove the ponds and landscape the area using Ecology BMP T5.13 —Post Construction Quality and Depth. This area with the amended soil can be modeled as "pasture" in a bypass basin and the vault enlarged accordingly such that the Ecology duration standard is met at the point of compliance. The ponds have been sized to accommodate flows and storage relating to the difference between proposed conditions and pre -developed forested conditions. Please see the Report for revised calculations and verbiage. Appendix D — "Raingarden & Vault Model -- Mitigated Scenario — Raingarden L The outlet structure is modeled as a "Riser Outlet Structure." The model is looking at the diameter of a round standpipe at a given elevation. The outlet is a 20x24 inch catch basin with a rectangular beehive grate. Provide the open area of the beehive grate and make it an equivalent to the area of round standpipe. For example, if the beehive has 2 square feet of open area, this is equivalent to a round standpipe 19.2 inches in diameter. Re -run the model with the revised parameters. The model has been revised to incorporate the parameters listed. 2. The plans show a b" diameter perforated underdrain for the rain garden. The underdrain is modeled with an Orifice Diameter = 0, meaning there are no opening in the pipe (model shows "Flow Through Underdrain" = 0 ac -ft). This modeling is not representative of the design please re- evaluate. By modeling the underdrain correctly this will likely change the amount infiltrated and outflow from the rain garden that will affect the vault sizing. Also, this model run shows 62.55% ENGINEERING DIVISION infiltration for this scenario. Later on in this Appendix, the Stage -Storage -Discharge table ("Landscape Swale Hydraulic Table") indicates zero cfs infiltration for all stages. Please re-evaluate. The model has been revised to include a % inch orifice in the end of the perforated drain pipe. 3. The modeling shows element "RAiNGARDEN SufaceEN." Please explain this element and how it is used in the modeling. This element nomenclature is generated by WKWMfor the rain garden element, the convergence of surface flow and subsurface flow into the rain garden. Appendix E — Pond Calculations 1. See "Page 5 — Flow Control" comments above. The ponds have been revised per the "Flow Control" comment above. SHEET C-110 — GENERAL NOTES 1. Revise General Notes to include compaction testing requirements for trench work in Highway 99. Compaction tests shall be performed and test results indicating a minimum 95% compaction shall be submitted to the City for approval prior to asphalt restoration. 2. Please revise Construction Sequence Note #10 to also state disturbed soils shall be compost amended per Chapter 5 of the Stormwater Manual. 3, Revise Water Service Note #1 to callout a requirement for granular sand surrounding (above and below) the domestic water line. These comments have been addressed on the plan, please refer to the revise Improvement Plans. SHEET C-200 —DEMOLITION & TESC PLAN 1. Along with note for temporary. driveway, please note that the driveway shall be removed and replaced prior to project completion. Note has been added to the plan, please refer to revised Plans.. 2. Add signage visible from Hwy 99 to clearly indicate the truck access so the Radia approach isn't used for construction access. Note has been added to the plan to provide signage, please refer to revised Plans 3. A silt fence is shown at the west end of the existing Radia parking lot in a location that doesn't allow for an appropriate vehicle turnaround. Place silt fence, chain link fence, or other barrier in a location that allows for the western most parking stalls a minimum 10 -foot area to turn around. It is understood that the last couple stalls in the lot may not remain accessible during portions of the construction activity. The fence or barrier shall be adjusted accordingly. BONN, KRAKNTGH�� ENGINEERING DIVISION The silt fence has been revised to provide more than 5 feet of back-up space by incorporating temporary caste placement to block stalls adjacent to the silt fence. Per discussion with Jeanie McConnell at the City of Edmonds, 5 feet is adequate for vehicle turn around. SKEET C-231— TESC DETAILS Detail 7 is not referenced on Sheet C-200. Will this pump be installed? Detail 7 has been removed from the plan set, please refer to revised Plan. SHEET C-300 — PAVING & HORIZONTAL CONTROL PLAN 1. In the area of the new parking lot and building, please remove the existing parking lot layer. Layer has been removed, please refer to revised Plan. 2. Add callout, reference detail and note signage requirements as appropriate for the one-way traffic barrier to be placed on the southwest side of the site. Callouts and signage have been added to provide emergency access only, please refer to revised Plan. 3. The turnaround area in the parking lot just south of the building shall extend a minimum of 10 -feet west of the last stalls in the lot. The curb location has been revised to provide 5 feet of back-up space. Per discussion with Jeanie McConnell at the City of Edmonds, 5 feet is adequate for vehicle turn around. 4. Will signage be placed indicated the drop off zone and parking restrictions? Please add detail for signage as appropriate. Signage has been placed at the drop-off zone for loading and unloading only, please refer to revised Plan. 5. It appears as though a new sign is being shown on the north side of the Radia driveway approach. Please confirm and add note that sign is to be approved under separate permit. Note has been added that sign is replaced per separate permit, please refer to revised Plan. 6. Add callouts for walls or include in the legend. Walls have been added to legend, please refer to revised Plan. 7. Add reference to the wall details provided within the plan set. Response to PLAN REVIEW COMMENTS ENGINEERING DIVISION Concrete retaining walls have been referenced to Structural Plans, please refer to revised Plan. 8. Clearly indicate location of trash enclosure and reference pertinent construction details. Location of trash enclosure has been indicated on plans, please refer to revised Plan. 9. Please label the two "structures" on the west side of the building near the pedestrian walkway and exit door. Are these utility vaults? Are the above grade of flush mounted? Above ground mechanical equipment has bee labeled on plans, please refer to revised Plan. 10. Callout requirement to replace curb/gutter and sidewalk improvements along Hwy 99 frontage consistent with WSDOT standards for curb/gutter and City standard detail E2.13 for sidewalk. Incorporate standard details into plan set. Callout and details have been added, please refer to revised Plan. SHEET C-330 — PAVING RETAILS 1. Detail 3 is not referenced on Sheet C-300. Please remove detail or show crosswalk location within the pian set. Detail has been removed, please refer to revised Plan. SHEET C-400 — GRADING AND DRAINAGE PLAN 2. In area of new parking lot, storm infrastructure and building please remove "existing facilities" plan layer. Layer has been removed, please refer to revised Plan. 3. Plans indicate connection of the foundation drains to the detention vault. Please confirm the vault has been sized to accept the additional flows (if any). No continuous groundwater flows are expected from foundation drains due to low groundwater level at approximately 10+ feet. Flow from the foundation drains is anticipated to be insignificant. 4. Label Pond 1 and Pond 2 and reference control structure details for each found on Sheet C-441. Ponds have been labeled on plans, please refer to revised Plan. 5. Please indicate how stormwater flows will discharge into Pond 1 (the southern pond). Response to PLAN REVIEW COMMENTS ENGINEERING DIVISION Stormwater flowing into Pond No. 1 is rainfall directly onto basin, no surface flow is diverted into Pond No. 1. Pond No. 1 is a local depression with a flow.control structure to limit the impact to Pond No. 2 which is confined by SR -99 and the adjacentparking above. Pond 1 discharges to Pond 2, discharge rates are listed in the Drainage Report. 6. Label the vault and reference the detail provided on sheet C-450. Vault has been labeled and referenced on Drainage Plan, please refer to revised Plan. 7. Label the vault control structure. Control Structure has been labeled and referenced on the Drainage Plan, please refer to revised Plan. 8. Label the rain garden and reference detail provided on sheet C-410. Rain Garden has been labeled and referenced on the Grading Plan, please refer to revised Plan. 9. The access drive shown on the south side of the property frorn the new parking lot to the southwest side of the existing Radia building doesn't appear to match into the existing concrete area shown on the Radia property. Will the concrete area be widened to match into the new asphalt? The concrete has been widened/revised to match the new asphalt width, please refer to revised Plan. 10. Please indicate where stormwater runoff from the SE corner of the south parking will flow to. It appears as though a small section will be directed onto the Radia site. Storm water runoff from the SE corner will continue to flow to an existing catch basin located behind Radia. The flow has been indicated on the Grading Plan, please refer to revised Plan. SHEET C-410 — RAIN GARDEN PLAN 1. Please include specs for the rip -rap dissipator pads Rip -rap pads have been specified on the plans, please refer to revised Plan. Additional specifications will be issued with plans to the Contractor at time of bidding. 2. Add RIM elevation at Type I basin Rim elevation has been added, please refer to revised Plan. CITY OF EDMONDS Response to PLAN REVIEW COMMENTS ENGINEERING DIVISION 1. Details 2 & 4 — please add drain rock, soil and seed specifications where appropriate. Callout depths as well. Please also indicate plant species to be placed in the rain garden. Drain rock, soil, and seeding has been specified on the plans, please refer to revised Plan. 2. Detail 3 - Per this detail the parking lot places a surcharge on the wall. Please provide engineered calculations for the design of this wall and any other walls in the design that support a surcharge. This surcharge has been accounted for, structural calculations will be provided. SHEET C-430 — STORM DRAIN PROFILES 1. Detail A - a. Callout pipe material, lineal footage and slope. Callouts for material, length, and slope have been added to plans, please refer to revised Plan. b. CB 09 indicates a 6" and 12" pipe, but both pipes connected to this basin are 12". Please revise. A 6"pipe is also connected to CP 09 from the North. Inverts into and out of this catch basin have been confirmed and are correct. 2. Detail B — a. Callout pipe material Material has been called out, please refer to revised .flan. b. Please confirm that the 12" pipe i.e. callout at CB's 02 and 03 are for in and out pipes. Due to sump condition, 12" inverts for catchbasins 02 and 03 are fur in and out pipes. Confirmed. 3. Detail C — a. Callout pipe material, lineal footage and slope for the section of storm pipe between the concrete pipe and CB -05. Callouts for material, length, and slope have been added to plans, please refer to revised Plan. b. Callout outlet pipe i.e, at CB -11 Outlet pipe callout has been added, please refer to revised Plan. 4. Detail D — a. The WQ unit indicates (4) solid checker plate covers, but the plans show 3. Please revise accordingly. WQ callout has been revised, please refer to revised flan. b. Callout outlet pipe i.e. at CB -ll Response to PLAN REVIEW COMMENTS ENGINEERING DIVISION Outlet pipe callout Inas been added, please refer to revised Plan. 1. The manhole details provided are for sewer manholes. Please revise to show storm manholes without channeling. The manhole details have been removed They are not referenced on the Plans, please refer to revised Plan. 2. Add note that steps shall be polypropylene. Note has been added, please refer to revised Plan. SHEET C-441— STORM DRAIN DETAILS 1. Details 1 and 3 reference sheet C-510, but sheet C-510 isn't included in the plan set. Should the reference be C-400? Correct sheet is now referenced, please refer to revised Plan. SHEET C-450 — DETENTION VAULT DETAILS 1. Show outfall from Kristar WQ unit. 2. Provide and reference details for Kristar WQ unit within plan set. Outfall has been shown and WQ unit has been detailed and referenced, please refer to revised Plan. SHEET C-451— DETENTION VAULT DETAILS 1. Detail C — Flow Control Structure: Please add note that shear gate handle shall hook on ladder step in closed position. Note has been added, please refer to revised Plan. ENGINEERING DIVISI®N SHEET C-500 - UTILITY PLAN 1. The DCDA and vault shall be located within 10 -feet of the Hwy 99 property line. The domestic water meter shall be located on the ROW side of the property line (outside of the sidewalk) with the hotbox on private property immediately after. With this change no public easement will be provided. Please revise plans accordingly. The DCDA and domestic meter are now located adjacent to the AIW, please refer to revised Plan. 2. Revise plans to show both the domestic and fireline taps off the watermain in Highway 99. Reference and include in plan set City standard detail E7.18.1. Separate taps for fire and domestic are shown off SR -99, please refer to revised Plan. 3. Trench in Highway 99 shall be restored to City standards — please reference and incorporate into plan set standard detail E4.2. Detail E4.2 is shown on sheet C-522, please refer to revised Plan. 4. Show curb/gutter and sidewalk removal and replacement as needed for this utility connection. Curb and sidewalk removal and restoration for utility connections is now shown on plans, please refer to revised Plan. 5. Add reference to details 1 and 2 on sheet C-520 and Detail 1 on sheet C-521 as they pertain to the DCDA and water meter. Note has heen added, please refer to revised Plan. 6. Please include in plan set and reference City standard detail E7. I I for RPBA in a hotbox. Detail E7.11 is shown on sheet C-522, please refer to revised Plan. 7. The water main on Hwy 99 is 8" DIP. Please revise callout of fittings at the valve cluster connection on Highway 99 to the following: a. (1) 8" x 8" DI tee (FLxFLxFL) b. (2) 8" MJ Couplers c. (3) 8" Gate Valve (MJxFL) Callouts have been revised to show existing 8" DIP waterline, please refer to revised Plan. 8. Revise the fittings at the Ere hydrant connection as follows: a. (1) 8" x 6" DI Tee (FLxFLxFL) b. (1) 6" Gate Valve (MJxFL) c. (1) 8" Gate Valve (MJxFL) d. (1) 8" MJ x FL Adapter Callouts for fittings at fire hydrant have been revised, please refer to revised Plait. CITY OF EDMONDS Response t® PLAN REVIEW COMMENTS ENGINEERING DIVISION 9. Please confirm water system pipe sizing ... Can the fire line be reduced to 4" after the hydrant? Can the domestic service and meter be reduced to 1 ''/2" or 1"? Domestic service pipe size is 2', required by Mechanical/Plurnbing. 10. 2 -- 45degree bends should be used in main line instead of 90degree bends. 2-45 degree bends typically provide more minor losses than 1®90 degree bend. City of Edmonds Standard Detail E7.9 shows thrust block installation for 90 degree bends. 11. DIP classification should say Class 52. It is unclear what CL200 is? CL200 is a minimum pressure class. Plans have been revised to show Special Class 52, please refer to revised Plan. 12. For the sanitary sewer system reference details provided on sheet C-522. Callout has been added, please refer to revised Plan. 13. Callout existing water service to Radia. Note has been added to reference existing Radia service, please refer to revised Plan. 14. Show location of existing sanitary side sewer to Radia. Location of'existing Radia side sewer is not known. A GIS based Sanitary Sewer map was provided to XPFF by the City of Edmonds, however it is unclear where the Radia property is serviced from. 15. An existing easement legend has been provided, but it is unclear where each of these easements exist on the property. Please identify pertinent easements on the plan set. Existing easement legend has been revised to reference only easements in the vicinity of the project, please refer to revised Plan.