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HomeMy WebLinkAboutDesign Analysis Letter - Correspondence - 500 BOXFORD STREET 1/28/2020 y DK ENGINEERING ASSOCIATES, INC. Woodland Ridge Phone: (603) 898-8516 V� 47 Enterprise Drive,#7 E-mail:dan@dkengineering.net P.O.Box 4260 www.dkengr.net Windham,NH 03087-4260 RECEIVED AUG 18 2016 August 17, 2016 TOWN OF NORTH ANDOVER HEALTH DEPARTMENT Town of North Andover V Health Department 1600 Osgood Street, Suite 2035 North Andover, MA 01845 Attn: Mr. Brian J. LaGrasse, CEHT—Director of Public Health RE: Design Analysis for Siting Subsurface Sewage Disposal System on 500 Boxford Street-Lot 1 &2 (Map 105C,Lot 42) Dear Mr. LaGrasse: The following discussion intended to illustrate our analysis in siting the proposed subsurface sewage disposal systems and buildings on Lot 1 and 2 at 500 Boxford Street. 310 CMR 15.232 (6), states, "Absorption trenches should be used whenever possible." It is our opinion that alternative systems have their place where absorption trenches are not practical or possible, such as replacement of failed systems. With this in mind, the houses and septic systems were moved around the lots and resized to accommodate the Title V setbacks and to the maximum extent possible, the North Andover Board of Health and Conservation setbacks. Specifically, Lot 1 The house was designed to accommodate the building setback requirements. As shown, the footprint of the dwelling minus the garage is approximately 1,300 s.f. The septic system was placed at the rear of the building and approximately 63 feet from the wetlands. Moving the septic system to the front of the lot as close to the lot line setbacks as possible, still required a variance for the setback to the wetlands. Another problem is that the building will not fit within the building setbacks as shown on the accompanying sketch. Additionally, construction of the driveway to the building would require work within the Conservation "25 foot no disturb zone". Lot 2 A similar analysis was performed on Lot 2. Moving the septic system in front of the proposed dwelling, would require the house to be set back 44 feet from the front lot line in order to meet the Title V setback requirements. This would move the building within the 50 foot building setback from the wetlands. Also, the system would be within 100 feet of the existing well. However, we were able to move the system closer to the front lot line providing a greater setback from the wetlands of approximately 74 feet. 41607 Letter re Design Analysis 2016-08-17.docx JN: 41607 J Mr. Brian LaGrasse August 17, 2016 Page 2 of 2 The septic systems shown on these two lots meet all the requirements of Title V as required. The relief requested is for the setback to the wetlands. We believe the building and septic system configurations provide the least environmental impact to the area. Accompanying this letter, please find the revised Subsurface Sewage Disposal Plan for Lot 2 dated August 17, 2016. As stated above, the system was moved closer to the front lot line to provide more of a separation from the wetlands. Since the system on Lot 1 as shown on the plans dated July 7, 2016 remained the same, the plans were not resubmitted. Should you have any questions regarding the siting of the construction elements of the site, please do not hesitate to contact me. Yours truly, DK ENGINEERING ASSOCIATES,INC. V��G Daniel Koravos,P.E. President cc: Mr. William MacLeod,Andover Consultants, Inc. DK ENGINEERING ASSOCIATES, INC. JN: 41607 DK ENGINEERING ASSOCIATES, INC. Woodland Ridge Phone: (603) 898-8516 47 Enterprise Drive,#7 E-mail:dan@dkengineenng.net P.O.Box 4260 www.dkengr.net Windham,NH 03087-4260 July 7,2016 RECEIVED Town of North Andover JUL 12 2016 Health Department TOWN OF NORTH ANDOVER 1600 Osgood Street, Suite 2035 H FA.RTMENT North Andover, MA 01845 `1 Attn: Mr. Brian J. LaGrasse, CEHT—Director of Public Health RE: Subsurface Sewage Disposal System Plan for 500 Boxford Street-Lot 2 (Map 105C,Lot 42) Dear Mr. LaGrasse: The following is in response to the review comment as outlined in your letter dated June 27, 2016: 1. The exi ting and proposed lot lines should be depicted on the design plan. On page two of three, lease depict the original three lots and overlay the proposed two lots being created with the proposed dwellings,proposed systems and all lot line setbacks, the 100'wetland buffer Zone,50'no build Zone and 25'no disturbance Zone. Response: Sheet two of three has been updated with the information requested. 2. Indicate why the soil absorption Jystem cannot be proposedgreater than 100 feet from the wetland resource area and whyyou cannot comply with section 3.9 of the North Andover Septic Regulations. There is an arra in the southwest corner of the proposed lot that is grrater than 100 feet from the wetland resource area. Please research alternative designs and site layouts that keep the systems out of the 100'buffer Zone or designs that achieve maximum feasible compliance. Please also note that Section 3.8 of the North Andover Septic Regulations state that a DEP approved device or alternative technology which reduces wastewater to levels below 30 mg/L BOD and 30mg/L TSS can be approved by the department without a hearing before the Board of Health. I have attached a rough sketch that shows 100 linear feet of primary and reserve trenches that are out of the 100'as a rough demonstration. (NA 3.9) Response: The layout of the trenches provided is not feasible. 310 CMR 15.232 (1) states "For all gravity flow distribution systems, a water tight distribution box designed to provide equal distribution of septic tank effluent to the distribution lines of the soil absorption system shall be provided between the septic tank and soil absorption system." With the varying lengths of the trenches as shown on the sketch, the trenches will not receive equal distribution per linear feet of trench. Even if the trenches could be as shown, the house would not meet the required setback from the trenches and building setback from the wetlands. In addition, the trenches are within 100 feet of the existing well within not permitted under Title V. 41607 Response Letter re Lot 2 SSDS Comments 2016-07-07.docx JN: 41607 Mr. Brian LaGrasse July 7,2016 Page 2of2 3. The wetland liner have not been confirmed or approved by the North Andover Conservation Commission and may be subject to change.A preliminary site walk by the Conservation Department may be beneficial and reduce additional revisions. Response: The variance requested is required to file with the Conservation Commission. The Notice of Intent filing will verify the wetland lines. 4. On sheet 3 of 3, remove the "untreated building paper"above the peastone layer in the soil absorption system. You may change this and use pet meable landscaping fabric. The use of the untreated building paper is not in compliance with Title regulations and will deteriorate rapidly once installed. This does not appear to accomplish the intended outcome stated in your letter dated June 15, 2016. Response: The "untreated building paper" has been removed from the detail. 5. Please submit an additional review fee of$125 with revised plans. Response: The additional fee accompanies this letter. I believe all you concerns have been addressed. Should you have any question or require additional information,please do not hesitate to contact me. Yours truly, DK ENGINEERING ASSOCIATES,INC. Daniel Koravos,P.E. President cc: Mr. William MacLeod,Andover Consultants, Inc. DK ENGINEERING ASSOCIATES, INC. ]N: 41607 DK ENGINEERING ASSOCIATES, INC. Woodland Ridge Phone: (603) 898-8516 47 Enterprise Drive,#7 E-mail:dan@dkengineering.net P.O.Box 4260 www.dkengr.net Windham,NH 03087-4260 June 15,2016 RECEIVED Town of North Andover JUN 212016 Health Department 1600 Osgood Street, Suite 2035 TOWN OF NORTH ANppVER North Andover, MA 01845 WALV()EPARTMENT Attn: Mr. Brian J. LaGrasse, CEHT—Director of Public Health RE: Subsurface Sewage Disposal System Plan for 500 Boxford Street-Lot 2 (Map 105C,Lot 42) Dear Mr. LaGrasse: The following is in response to the review comment as outlined in your letter dated June 9, 2016: /1. The Assessor's map and lot numbers are not indicated on the design plan (NA 3.2). Response: The Assessor's Map and Lot numbers have been added to the title block and on sheet 2. 2. The existing and proposed lot lines should be depicted on the design plan. Response: The existing and proposed lots lines have been added to sheet 2. ✓ 3. TP-6 was not depicted on the design plan (310 CMR 15.220(4)(h)). Response: TP-6 has been added to the design plan (sheet 1). 4. On sheet 1 of 3, the depths of the test pits and the color of C horizons are incorrect. Response: The discrepancy has been corrected and calculations adjusted. ✓ 5. On sheet 1 of 3, the depth of the ESHWT in TP4 is incorrect. The soil absorption system design is based on this elevation and needs to be revised to maintain the 5'separation from the bottom of the trenches to the ESHWT. Response: The discrepancy has been corrected and calculations adjusted. 6. The percolation test results should indicate a percolation rate of<2 minsl inch. Response: The "less than" symbol has been added to the percolation rates. /7. On sheet 1 of 3, the graphical representation of the test pits should be shown as they were excavated instead of circles as depicted in the site plan view. Response: The rectangular test pit symbols have been added to the plan. 41607 Response Letter re Lot 2 SSDS Comments 2016-06-15.docx JN: 41607 w� Mr. Brian LaGrasse r June 15, 2016 Page 2of3 8. Indicate why the soil absorption ystem cannot be proposed greater than 100 feet from the wetland resource area and maintain compliance with section 3.9 of the North Andover regulation. There is an area in the southwest corner of the proposed lot that is greater than 100 feet from the wetland resource area. Response: Considering the required setbacks from the property lines and the required size of the proposed septic system, the area outside the 100 foot wetland buffer zone in the southwest corner of the lot is insufficient to contain the system. 9. No benchmarks were depicted on the design plan (310 CMR 220(4)(q)). Response: A benchmark has been added to the plan and a note stating additional benchmarks will be set prior to construction. / 10. The foundation drain location and elevation were not depicted on the design plan(NA 3.2). Response: The foundation drain has been added to the plan on sheet 1. Also on sheet 1 note 17 was added indicating the setback requirements. 11. Depict the setback distance from the proposed well to abutting soil absorption systems to ensure compliance with 310 CMR 15.211. Response: The well is existing. To the south of the existing well, a 100 foot offset extends approximately two feet outside of the right-of-way of Boxford Street. The 100 foot offset from the existing well to the north, east and west is totally contained within the lot. J12. On sheet 1 of 3, the building sewer line proposed will likely need a bend either exiting the dwelling or upon entering the septic tank Please review and propose bends as needed to ensure the inlet tee is located below the manhole access port(310 CMR 15.227(1)). Response: The septic tank has been relocated to provide for the pipe from the house to the tank to be perpendicular to both. 113. On sheet 1 of 3, the septic tank appears to be less than 10'to the proposed dwelling(310CMR 15.211). / Response: The septic tank has been relocated. / 14. On sheet 3 of 3, the loading (H-10 or H-20) of the septic tank was not depicted on the design plan (310 CMR Response: Note 3 on sheet 3 has been added stating that the septic tank shall meet H10 loading requirements. / 15. 6"of crushed stone is required beneath the distribution box(310 CMR 15.221(2)). Response: In the Concrete Distribution Box on sheet 3, note 3 was added stating that 6 inches of crushed store is required beneath the distribution box. 16. On sheet 3 of 3, explain the purpose for the "untreated building paper" above the peastone layer in the soil absorption ystem. Also explain how the use of the untreated building paper is in compliance with Title 5 regulations. DK ENGINEERING ASSOCIATES, INC. )N: 41607 Mr. Brian LaGrasse f June 15,2016 Page 3 of 3 Response: The "untreated building paper" is provided to assist in preventing fines from entering the stone trenches and help minimize surface water from inundating the system. I believe all you concerns have been addressed. Should you have any question or require additional information, please do not hesitate to contact me. Yours truly, DK ENGINEERING ASSOCIATES,INC. Danie �oravos,P.E. President cc: Mr. William MacLeod,Andover Consultants, Inc. DK ENGINEERING ASSOCIATES, INC. )N: 41607