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20140915094156426.pdf2707 ne -ENGINEERING, INC. ess September 10, 2014 Jennifer Lambert Engineering Technician City of Edmonds Public Work Department 1-kE: First Engineering Plan Review Comments for Coleman — 902 — 9111 Ave S, Permit Application #: BLD20140189 This letter isintended tosummarize the changes made tothe engineering reviewed during the first permit review for this project. This letter addresses comments from you along with other staff members which were provided in an email dated August 29, 2014. | have tried toformat this letter to match your comment email for easier understanding, GENERAL NOTES 1) Note #1 — revise "2010 VV8D0T/AUPVVA standard..." to oh*bs "Current Edition of the 1) Add the utility purveyor information. Purveyor information added bmCover Shoot. 2) Please add a note to the plans that state the existing utilities will be removed and/or capped under the demolition permit. Note added b7Cover Sheet. 3) Please revise the site map hzbeconsistent with the other sheets emneeded. Kall WAI U IMI 1-44 1 � �_ U17n GENERAL NOTES 1) Add the following note, "All disturbed soils hubecompost amended." ;� .- - ne ENGINEERING, INC. t 47-S.:3E9"7.:3S20 _ _ DRAINAGE AND UTILITY PLAN (pg. 3 of 4) GENERAL 1) The minimum driveway width shall be 12'. Per the drawings, the existing shared access is less than 12' and therefore, the driveway will need to be widened to a minimum of 12'. The shared access is 17' wide. Please refer to Architectural plans for easement. WATER 1) It appears that a fire sprinkler system is required for this property. The existing water service line from the watermain to the meter is not the appropriate size and a new tap will be required. a. Please show the new line from the watermain to the house. New waterline is shown from the watermain to the house. b. Please show the back of the water meter located at the property line (where the water meter is within the right-of-way). New water meter is shown located at the eastern property line, within the right- of-way of 9th Ave S. c. Please add a note that a 1" meter is to be installed. Note added. Please refer to Drainage and Utility Plan. d. Please label the water service line as 1 '/" and note the pipe material and tracer wire. New water service line is labeled as copper 1 '/a" service line with tracer wire. SEWER 1) As stated in the incomplete submittal comments dated 4/24/14 and in an email dated 8/20/14, if the sewer is to follow the same path as the existing sewer (as shown on the plans) an easement(s) is required that allows for the sewer servicing 902 9th Ave S to run through private properties. Please provide the easement(s) to the City. The proposed SFR will be connected to the sewer in 9th Ave S. b. If an easement does not exist or cannot be obtained, please show how the site will be connected to sewer. I. Show the side sewer from the main to the house. Side sewer from main in 9th Ave S to proposed house shown. ii. Label how the connection will be made at the sewer main. Note added to Drainage an Utility Plan. iii. Label the side sewer and lateral as proposed or existing. Side sewer and lateral labeled. iv. Show a 6" cleanout at the property line. Please add a note that the 6" cleanout at the property line will have a 12" cast iron lamphole cover with 1/2" hexbolts. Cleanout added at property line with note. -►01 OMECXAA M70'7_ ENGINEERING, INC. t,42S.:3S7.:3.S20 v. Please label the pipe material and size. The sewer lateral must be 6". Once on private property the sewer may reduce to 4". A 6" PVC pipe is to be used and labeled. vi. Show a cleanout located within 2' of the house, at any 90° bend, when there is less than 3' between two 45° bends, and when there is more than 100' between cleanouts. A cleanout is shown within 2' of the house. vii. Please show the invert elevations at the main and the house so that slope and coverage can be verified. If the slope of the pipe exceeds 20% the pipe will need to be anchored. Invert elevations at the main and house are shown. Slope of pipe does not exceed 20%. If this connection requires a grinder pump, please show/provide the following: This connection does not require a grinder pump. 3ZT 1) If the site has more than 5000 sq ft of impervious surfaces, all stormwater management systems must be designed by a licensed engineer. The pre -sizing chart in Handout #E72A cannot be used regardless if less than 5000 is proposed to discharge to the detention system. Please see comments below by Jerry Shuster. The new stormwater management system has been designed using Section 5.7 of the Edmonds Stormwater Code Supplement for Category 2 small site projects. Handout E72 was no longer used. The total proposed impervious surfaces for the site (new plus replaced) will go to the detention system. 2) If there are portions of surface water runoff not located on the subject site that will discharge to the onsite stormwater management system, the system will need to be sized to account for the additional surface water runoff. Please show what areas of the driveway/shared access road will discharge to the onsite stormwater management system. All new plus replaced impervious surfaces, including NPGIS and PGIS will dischargeto the onsite detention tank. No offsite areas are proposed to discharge to the onsite stormwater management system. The existing offsite shared access road drains west. 3) Please show where the footing drains will discharge to. The footing drains will connect into the pump well. Please see footing note on Drainage and Utility Plan sheet. A line has been added to plans to show the connection to the pump well. _ QMEOAM , _ _ ENGINEERING, INC. t -42S-ZS7.:3820 F1-1 11677 1) A "Level Spreader" is proposed for approximately 1,000 square feet of runoff. This is actually "Dispersal Trench with notched grade board" and should be referred to as such. The cited minimum 25 foot flow path does not apply to this site since the area downstream of the proposed dispersal trench is a steep slope (defined as 15% or greater). Steep slopes require a 50 foot flow path. There does appear to be 50 feet between the proposed spreader and the west property line, however, the flow will not be dispersed and therefore a flow credit cannot granted. First the geotechnical report basically says that no water will infiltrate and second, there is a cutoff trench designed to intercept the flow and convey it to the yard drain that connects to the detention system via pump. Flow dispersion is discouraged in highly urban environments. The site classifies as a Category 2 Small Site Project, therefore the detention sizing in handout E72A are not applicable. The introduction of the handout says: "if your site is a Category 2 Small Site Project or a Large Site Project that will have stormwater detention system, this handout cannot be used. See the Supplement for more details." The detention system must be designed per Section 5.7 of the Edmonds stormwater code supplement for a Category 2 small site project. The new stormwater management system has been designed using Section 5.7 of the Edmonds Stormwater Code Supplement for Category 2 small site projects. Due to the steep slopes, dispersion and infiltration are not feasible and will not be used. Instead, the detention system was resized for the total new plus replaced impervious surfaces onsite (5,901 sf) using the Supplement Code. Please see the drainage plans and report for more details. 2) Pump calculations (not just cut sheets) need to be included per pumping policy (http://www.edmondswa.gov/images/COE/Government/Departments/Public Works/Policies/ENG R-DEVSTM-2001-02.Pumping. Private_Property.pdf). See enclosed example. Please see Appendix `A' in the drainage report for pump calculations using WWWM. 3) Once the comments above have been addressed there may be additional comments. OK Thank you for taking the time to review the revised plans for this project. Please feel free to contact me with any questions you may have. Sincerely, Rachel A. Jacobs Omega Engineering, Inc.