Loading...
HomeMy WebLinkAbout- Correspondence - 106 ROCKY BROOK ROAD 7/6/2020 (3) The Morin-Cameron SEP pRTH A BEN�R September 20, 2019 '(OH��SNpEPPRj Mr. Brian J. LaGrasse Director of Public Health 120 Main Street North Andover, MA 01845 Re: Subsurface Sewage Disposal System Plan - 106 Rocky Brook Road Dear Brian: We are in receipt of your review of the septic design for the above referenced property dated September 9, 2019. Please find enclosed the following: • 3 sets of the revised Sanitary Disposal System Repair Plans • DEP Effluent Filter approval letter • Pump Performance Curve • Revised soil evaluation forms On behalf of Aleksandr Shneyderman, The Morin-Cameron Group, Inc. has prepared the following responses to your comments. For your convenience the response comments are numbered in the same order and correlate to the numbered comments in your letter: 1. A note stating "Note: All pipe to be 4" P.V.C. (SCH 40)" is shown on the system centerline profile on sheet 2 of 2. 2. A note stating that "The existing property is not located within the Watershed Protection District" is shown as note 6 in the Setback Certifications on sheet 1 of 2. 3. The brand and model of the proposed effluent filter (Zabel A1800 or approved equal) has been added to the plan on sheet 1 of 2 and added to the septic tank detail on sheet 2 of 2. A copy on the MassDEP approval letter for this filter is enclosed. 4. A note indicating that the "Effluent filter shall be serviced at least once per year" has been added on sheet 1 of 2 and on the septic tank detail on sheet 2 of 2. 5. The septic tank and pump station details state that the tanks are to be monolithic. 6. A survey certification has been added to the plan on sheet 1 of 2. CIVIL ENGINEERS • LAND SURVEYORS • ENVIRONMENTAL CONSULTANTS • LAND USE PLANNERS 66 Elm Street, Danvers, MA 01923 978.777.8586 FAX 978.774.3488 Providing Professional Services Since 1978 www.morincameron.com Mr. Brian LaGrasse September 20, 2019 Page 2 7. If the septic tank is required to be replaced, the existing building sewer will be inspected and replaced with a 4" PVC (Sch 40) pipe, if required. Construction Note 2 on sheet 1 of 2 has been revised to reflect this. 8. The septic tank detail and profile have been revised to show the access cover at finish grade over the septic tank outlet 9. A 6 inch stone bed is shown on the detail for the septic tank and pump station. The bottom of the stone base will be located on native ground. Per 310 CMR 15.221 (2) "native ground with a six inch aggregate base is otherwise acceptable", and no further compaction is required. A minimum of 9 inches of cover has been specified for the septic tank and pump chamber on the system profile on sheet 2 of 2. 10. Buoyancy calculations for the pump station are shown on sheet 2 of 2. If a new septic tank is required to be installed buoyancy calculations should not be required since the new tank will be set at the same elevation as the existing tank and there have been no issues with the existing tank "floating" due to high groundwater. If the Board of Health requires buoyancy calculations for the septic tank they can be provided. 11. The proposed pump station and septic tank, if required, are monolithic and, therefore, the tanks are watertight. A note has been added to the pump station and septic tank details stating, "Alljoints, penetrations and risers shall be made watertight." 12. The tank penetrations for the pump chamber and proposed septic tank, if needed, are not within 12" of the ESHWT. The approximate distance from the pump tank outlet invert to the ESHWT is 1.3 feet and has been added to the system profile. 13. The distribution box is required to be set level and there is only one outlet invert shown so it is implied that all outlets are set at the same elevation. The first 2 feet of pipe coming out of the D-Box is shown at 0% on the profile. A note has also been added to the D-Box detail that all outlet inverts are at the same elevation and that the first 2 feet of pipe leaving the D-Box shall be set level. 14. Per the distribution box detail, the inlet is shown with a sanitary tee. The top of this tee is at a minimum 6" above the outlet invert. The detail has been revised to show this dimension. 15. A note indicating that the soil below the crushed stone is to be compacted has been added to the distribution box detail. 16. A note indicating that distribution box is to be made watertight has been added to the distribution box detail. 17. The distribution box is shown to have a 24 inch dia. watertight access riser with frame and cover to within 6 inches of finish grade on the system centerline profile on sheet 2 of 2. Mr. Brian LaGrasse September 20, 2019 Page 3 18. The force main and pump calculations have been revised to show a 2" force main. The pump proposed has not changed. A modified pump performance curve is enclosed. 19. The soil evaluation forms have been revised to be on the DEP approved forms and are enclosed. 20. Per general note 24 on sheet 2 of 2, all "Fill, topsoil and subsoil for a distance of 5 feet beyond the leaching facility" is to be removed. The C' layer is a SL, Fill mix (as shown on the soil logs on sheet 1 of 2) and wilt, therefore, be required to be removed. For clarification the removal of the C' layer has been added to General Note 24. 21. An inspection port has been added to the plan view and system profile; a detail of the inspection port was included on the original plan. 22. The orifice size has been added to the leach bed detail on sheet 2 of 2. 23. The proposed grading meets the breakout requirement; additional spot grades of 136.7' have been added to the plan view on sheet 1 of 2 to clarify the proposed grading required. 24. Per the original approved septic design for this property the septic tank is 1,500 gallons which is sufficient for a 4 bedroom dwelling. An as-built plan was prepared by the original design engineer and the system installation was signed off by the Board of Health so it is assumed that the existing septic tank is 1,500 gallons as per the original design plan. The information in the Title 5 report prepared by F. Paul Cardone dated 5/16/19 shows a septic tank size that appears to be consistent with a 1,500 gallon septic tank. If an inspection determines that the existing septic tank needs to be replaced it will be replaced with the tank specified on the proposed design plan that complies with Title 5. Calculations for sizing the new septic tank, if required, are shown on sheet 2 of 2. We trust these responses satisfy your questions and concerns. If you have any additional questions, please do not hesitate to contact our office. Sincerely, THE MO,RIIN-CAMERON GROUP, INC. John M. Morin, PE Principal JMM/kmm Attachments cc: Aleksandr Shneyderman X:\Shneyderman,Aleksandr\3884\Docs\BOH\Response Comments.dou