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HomeMy WebLinkAbout2007-06-27 Peer Review TOWN OF NORTH ANDOVER PLANNING BOARD ENGINEERING REVIEW OF SITE PLAN AND WATERSHED SPECIAL PERMIT FOR CONFORMANCE WITH THE TOWN OF NORTH ANDOVER ZONING BYLAW Site Plan Title: Brooks School New Science Building VHB No.: 09280.31 Site Plan Location: Brooks School, Great Pond Road,North Andover,MA Applicant: Brooks School 1160 Great Pond Road,North Andover,MA Applicant's Engineer: Rist-Frost-Shumway Engineering,P.C.,71 Water St,Laconia,NH Plan Date: March 16, 2007 Review Date: 04-19-07 The plan was reviewed for conformance to the 1972 Town of North Andover Zoning Bylaw(last amended May 2004). The Applicant has submitted the following information for VHB's review: • Application for Site Plan and Watershed Special Permit, • Supporting Documentation for Site Plan Review and Watershed Special Permit dated March 15,2007 • Campus-side Parking Report for Brooks School dated August 10, 1999 • Drainage Calculations for New Science Building at Brooks School dated March 2007 • Brooks School New Science Building Planning Board Submission Plans- 16 Sheets-AO.0, A2.01,A2.02,COAL,CO.02,C1.01,C2.01,C3.01,C3.02,C4.01,L1.00,L2.00,L3.01, L3.02,L4.00 and EO.1 dated March 16,2007. The following comments note non-conformance with specific sections of the Zoning Bylaw or questions/comments on the proposed design and VHB's recommendations/suggestions. Town of North Andover Zoning Bylaw 1. (4.136.3.a.ii.2)A new building is proposed and is allowed by special permit. (no action required) 2, (4.136.3.b.ii.1) A surface detention basin,inlet drainage pipe and detention basin outlet is proposed and is allowed by spectral permit. (no action required) 3. (4.136.3.c) There are no proposed changes to this area. (no action required) 4, (4.136.4.c.iv) The Applicant should provide documentation that there is no reasonable alternative location for the proposed detention basin outside the non-discharge buffer zone. 5. (8.3.5.c.ii) A waiver has been requested from the requirement for a boundary survey. 6. (8.3.5.c.xix) A waiver has been requested from the requirement for a traffic study. 1 \C:\DOC UM E-1\mi ppolH\LOCALS-]\Temp\09280 .BmokaS,hoorxienmB]d&do General Site Plan /Drainage Comments 7. C2.01 Proposed Site Plan a. It is not clear what the"12 inch Catch Basin" refers to in Drainage Note 28,29, 31 &32. The catch basin detail is for a 4 ft.diameter structure with a 2 ft opening. If a 12 inch opening or different type of catch basin is proposed that a detail should be provided. b. There is no drainage structure or pipe shown at Drainage Note 10. c. There is no flared end invert elevation shown at Drainage Note 20. d. There is no pipe shown between the roof drain at Drainage Note 25 and the concrete cistern at Drainage Note 11 e. The number of the proposed Cultec 330HD units should be added to Drainage Note 15 as well as the existing high groundwater elevation. f. A riprap emergency over flow weir and channel should be provided for the proposed detention basin. 8. C3.01 Erosion and Sedimentation Control Plan—A legend or note should be added stating that the "SF"line shall be composed of a silt fence and hay bale erosion control barrier. 9. C4.01 Civil Details—The following construction details should be provided: a. 18 inch PVC drain hand hole b. 8 inch x 6 inch in-line drain c. 3000 gallon precast concrete cistern d. Downstream Defender with proposed unit diameter, inlet and outlet pipes e. Detention basin berm with impermeable core f. Detention basin riprap overflow weir and channel 10. Drainage Calculations a. The Soil Suitability Assessment Form 11 for the test pit logs are very poor light and very difficult to read. Better copies that are readable should be submitted. b. Calculations justifying the assumed 4.6 inch/hour exfiltration rate should be provided. c. Calculations justifying the proposed sediment fore-bay volume should be provided. d. The Lower Wet/Dry Garden Pond 16 P drainage calculations show a weir elevation of 168.0 while Sheet L2.00 Grading Plan shows a weir elevation of 167.5. 11. Existing Conditions Plan(Pre-Development Areas) a. It appears that the following Drainage Structure Labels are reversed: CB4E should be CB5E, CB7E should be CB6E, CB5E should be CB4E and C136E should be C87E. 12. Proposed Site Plan(Post-Development Areas) a. Drainage Area IOS appears to be labeled 9S. b. The location of CBIOP is not shown. c. The location of CB23P is not shown. 2 \C,\DOCUME-1\mippol£l\LOCAL5-1\Temp\o9280M-Br k&Schook5dPm*B1d&doc It is recommended that the Applicant provide WRITTEN RESPONSES to the issues and comments contained herein. Reviewed by: Date: Paul S. Carter,P.E. Project Manager W-Highway and Municipal Checked by: Date: Timothy B.McIntosh,P.E. Project Manager—Highway and Municipal 3 \C:\DDCUME 1\mippolit\LOCAi.S-I\-Femp\097NOLBrookeSchoaScienceBldg.doc TOWN Or NORTH ANDOVER PLANNING BOARD RECEIVED ENGINEERING REVIEW OF SIIE PLAN AND WAIERSHED SPECIAL pF q q FOR CONFORMANCE WTI IT THE I 1 2007 'I OWN OF NORI If ANDOVER ZONING BYLAW NORTH ANDOVER PLANNING DEPARTMENT Site flan Title: Brooks School New Science Building VIII3 Nro, 09280.31 Site Plan Location: Brooks School,Great Pond Road,North Andover,MA Applicant: Brooks School 1160 Great Pond Road,North Andover,MA Applicant's Engineer: Rist-frost-Shumway Engineering,P C,71 Water St,Laconia, NH Plan Date: March 16,2007 Review Date: 04-19-07 2"`'Review Date: 05-10-07 T he plan was reviewed fbr confbimance to the 1972 Iown of North Andover Zoning Bylaw(last amended Iuly 10,2006), The Applicant has submitted the following infbrmation for VHB's review: • Response to Comments Memorandum dated May 2,2007 • 1~arnr 11—Soil Suitability Assessment slated 2/23/07 and Percolation Test Form 12 dated 2/23/07 • Diainage Calculations for New Science Building at Brooks School dated March 2007,revised May 1,2007 + Brooks School New Science Building Planning Hoard Submission Plans_3 Sheets-C2.01, C4.01 and C4 02,dated March 16,2007,revised May 1,2007 The following comments note non-confotmanee with specific sections Of the Zoning Bylaw or questions/comments on the proposed design and VHB's recommendations/suggestions Oa iginal comments are shown in regular font. The latest comments are in bold Town of North Andover Zoniji B law l. (4 136.3 a.ii.2)A new building is proposed and is allowed by special permit (no action required) 2. (4.136 3,b ii 1) A surface detention basin, inlet drainage pipe and detention basin outlet is proposed and is allowed by special permit. (no action required) 3 (4.1.36 3 c) There are no proposed changes to this area. (no action required) 4 (4..136 4 aiv) the Applicant should provide documentation that there is no reasonable alternative location for the proposed detention basin outside the non-discharge buffet zone Comment addressed. The Applicant's Engineer has submitted an explanation of why the proposed detention basin needs to be located in the non-discharge buffer zone, 5. (8 3.5 e ii) A waiver has been requested from the requirement for a boundary survey 6 (8 3.5 e xix) A waiver has been requested from the requirement for a traffic study. \\\Mawn�rlle\Of2gt13(\�(0��,�„��pyZ�,rl3ropk55��1W€Scie"cerifdgree ieti�2 do; General Site Plan/Drama a Comments 7. C2 01 Proposed Site Plan a It is not clear what the"12 inch Catch Basin"refers to in Drainage Note 28,29,31 &32. The catch basin detail is for a 4 ft.diameter structure with a 2 ft opening ff a 12 inch opening or different type of catch basin is proposed that a detail should be provided Comment addressed. b There is no drainage structure or pipe shown at Drainage Note 10 Comment addressed. c. 'Thew is no flared end invert elevation shown at Drainage Note 20. Comment addressed.. d. There is no pipe shown between the roof drain at Drainage Note 25 and the concrete cistern at Drainage Note 1 I Comment addressed. e. The number ofthe proposed Cultec 3 301-ID units should be added to Drainage Note 15 as well as the existing high groundwatei elevation. Comment pat dally addressed.. the existing high groundwater elevation should be added to Drainage Note 15. f. A iiprap emergency over flow weir and channel should be provided for the proposed detention basin Comment addressed. 8. C3 01 Erosion and Sedimentation Control flan—A legend or note should be added stating that the "SF"tine shall be composed of-a silt fence and hay bale erosion control barrier. Comment addressed. 9 C4 01 Civil Details—The following construction details should be provided: a. 18 inch PVC drain hand hole Coin men t adds essed. b 8 inch x b inch in-line drain Comment addt essed. c. 3000 gallon precast concrete cistern Comment adds essed. Also note that the size of the elster n has been changed to 2000 gallons d. Downstream Defender with proposed unit diameter,inlet and outlet pipes Comment par tially addressed. The detail shows an 18 inch outlet pipe while Drainage Note 17 calIs for a 12 inch outlet pipe. c. Detention basin berm with impermeable core Comment addressed. 2 \\\Mawalr\te\W280 3t\:lots\memos\0928031-BrookSchootScience6ldgreriew2 doe { t. Detention basin riprap overflow weir and channel Comment addressed. 10. Drainage Calculations a. The Soil Suitability Assessment Dorm 11 for the test pit logs are very poor light and very difficult to lead. Bettet copies that arc readable should be submitted Comment addressed, b. Calculations justifying the assumed 4 6 inch/houi exfiltiation rate should be provided. Comment addressed. c Calculations Justifying the proposed sediment foie-bay volume should be provided. Comment addressed. d the Lower Wet/Dry Garden Pond 16 P drainage calculations show a weir elevation of 168 0 while Sheet L2.00 Grading Plan shows a weir elevation oft67 5 Comment not addressed. the Lower Wet/Dry Garden Pond 16 P drainage calculations now show a weir elevation of 168.3. 11. Existing Conditions Plan(Pre-Development Areas) a. It appears that the following Drainage Structure Labels are reversed: CB4E should be ME, CB7E should be CB6E,CB5F should be CNE and CB6E should be CB7E. Comment addressed. 12 Proposed Site Plan(Post-Development Areas) a Drainage Area 10S appears to be labeled 9S. Comment addressed. b The location of CBI OP is not shown Comment addressed. c The location of'CB23P is not shown. Comment addressed. It is recommended that the Applicant provide WRIT IDN RESPONSES to the issues and coirunents contained herein. 1! D Reviewed b ` �, Date: 7 Paul S Cattei,P E Projec Manager—Highway an d M nicipal Checked by: �y Date: Timothy B 1• elntosh,P E. Project Manager--Highway and Municipal 3 \\\?.Fwatr\re\!]42A0 31\das\memas\@r28p31 F3raolc55[hoolS�ence8ldgreviex2.doc 1poollito, Ma From: John Scott Uscott@rfsengineering.com] Sent: Thursday, April 26, 2007 3:48 PM To: Ippolito, Mary Cc: samoset24@aol.com; darons@architerra-inc.com; JTrovage@brooksschool.org Subject: [SPAM] Brooks Sci Bldg-Consultant Review Comments Importance: Low We have received the memo of responses from VHB, and offer the following responses. Revised plans and documentation to follow. Casing the numbering in the VHB memo: 1. No action required. 2. No action required. 3. No action required. 4 . The detention pond must be downhill from the site to maintain gravity flow. The only such location which is not in the non-discharge zone lies to the north of Holcombe House, a faculty residence. Locating a detention pond in the "side yard" would be an aesthetic negative to this dwelling. This is also a prime location for possible future buildings for the school. The location chosen for the pond is also fairly close to Holcombe House ,but it is to the rear of the house, is significantly downhill from the house and thus less visible, and adjacent to the pump station, another campus infrastructure element. Finally, the non-discharge zone boundary bulges in this locale only because the outfall from a long-standing storm drain creates a drainage ditch to the southeast, which technically meets the definition of a tributary to the lake, and thus the boundary arcs inland from the normal boundary closer to the lake shore. If that was not the case, almost all of the pond would be in the general zone. 5. Waiver request. 6. Waiver request. 7.a. The 12" basin is intended to be a PVC basin; detail has been added to plans. 7.b. Typo - has been erased. 7.c. End invert elevation added. 7 .d. Pipe inadvertently left off; is now shown. 7 .e. Seven units; note added. 7. f. Secondary outlet added, with detail - similar to that for pond at Brooks Athletic Facility. 8 . See Civil Linetype Legend on C0.01. The "SF" linetype is for silt fence with hay bales. 9.a. The 18" basin is intended to be a PVC basin; detail has been added to plans. 9.b. Detail for 8" x 6" In--Line Drain added (intended to pick up downspout flow with air gap) . 9.c. Detail of cistern will be added. It will be basically a precast concrete septic tank without baffles. Students and staff will use a hand pump to supply irrigation water as needed in the greenhouse. 9.d. Details and sections of the Downstream Defender have been added. 9.e. We have discussed the impermeable core with VHB. After consultation with Haley & Aldrich, the project geotechnical engineer, we intend to make use of the Glacial Till underlying the Science Building site for the core of the berm. It will be tested to assure permeability less than .0001 cm/sec, and screened to remove stones and fragments larger than 6-in. If the permeability of this Till falls short, we'll use imported material. 9. f. See response to 7 . f. , above. 10.a. We will provide darker copies of the forms from Norse Envirnonmental .for better readability. 10.b. The perc rate is as recommended in the Norse report which you 1 t coO dr'.t read (see 10.a. , above) . 10.c. Calcs on the forebay sizing will be provided. 10.d. The 167.5 weir elevation on L2.00 is correct; drainage calcs corrected. ll.a. Typos will be corrected. 12.a. Correction made. 12.b. Location will be shown. As is inevitable on a major project, the design team and the school have agreed to some alterations in the site plan since the original submission, which we will include in the revised plans - along with explanations and backup documentation. In general, the alterations are (1) the wet/dry garden and courtyard layout have been simplified, and (2) the configuration of the detention pond has been modified and the volume reduced. Backup calculations will be provided, of course. We will submit the revised plans and documentation shortly. We look forward to meeting with the Board on Tuesday evening. A copy of this e-mai will be faxed to you, just to be sure you get it. John L. Scott, P.E. Manager, Civil Engineering Rist-Frost-Shumway Engineering 71 Water Street Laconia, NH 03246 t: (603) 524-4647, ext. 142 f: (603) 528-7653 e: jscott@rfsengineering.com w: www.rfsengineering.com 2