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Home My WebLink About05/02/2018 - 1st HWG Stormwater Peer Review - - 1429 OSGOOD STREET f Horsley Wi ittle n G ro u�p, Sustainable Ehvironmental Solutions Ali%„ lil° 294,Washington Street-Spite 801 -Boston, A 02108 May 2, 2018 Ms. Monica Gregoire, Staff Planner Planning Department Town of North Andover 120 Main Street North Andover, Massachusetts 01845 Ref: Mixed-Use Development 1429 Osgood Street, North Andover, MA Dear Ms. Gregoire and Board Members: The Horsley Witten Group, Inc. (HW) is pleased to provide the North Andover Planning Board with this letter report summarizing our initial review of the Site Plan and Drainage Report for the proposed mixed-use redevelopment at 1429 Osgood Street, North Andover, MA. The plans were prepared for Oliver Enterprises, Inc. (Applicant) by Allen & Major Associates, Inc. We understand that the project involves retaining the existing structure while reconfiguring the onsite parking lot, including the installation of new sidewalks, utility improvements, and stormwater management on a 1.96± acre parcel. The proposed work is within the 200 foot Riverfront Area of an unnamed stream and within the 25 foot buffer of the adjacent bordering vegetated wetlands (BVW). The following documents and plans were received by HW: • Drainage Report, 14 Osgood Street, North Andover, prepared by Allen & Major Associates, Inc., dated April 12, 2018; and • Corridor Development District Plan for Mixed-Use Development, 1429 Osgood Street, North Andover, MA, prepared by Allen & Major Associates, Inc. dated April 12, 2018, which includes: o Cover Sheet o Abbreviations & Notes C-001 o Abbreviations & Notes C-002 o Existing Conditions Plan V-101 o Site Preparation Plan C-101 o Layout and Materials Plan C-102 o Grading and Drainage Plan C-103 o Utilities Plan C-104 o Landscape Plan L-101 o Landscape Plan L-102 o Landscape Plan L-103 o Details C-501 o Details C-502 r I a . rn 91 @H'�orsleyWittenGroupHorsley le roue, I nc. Town of North Andover May 2, 2018 Page 2of5 Stormwater Management Design Peer Review HW offers the following comments concerning the stormwater management design as per the Massachusetts Stormwater Handbook (MSH) dated February 2008, the North Andover Stormwater Management and Erosion Control Regulations (Stormwater Regulations) adopted February 5, 2011, and the North Andover Stormwater Management and Erosion Control Bylaw (Bylaw). In accordance with Article 160-4 of the Bylaw the proposed redevelopment is considered a Regulated Activity that is required to obtain a land disturbance permit from the Planning Board. Therefore in accordance with Section 7.0 of the Stormwater Regulations a Stormwater Management Plan shall be designed to incorporate the criteria of the MSH as well as additional criteria presented in the North Andover Stormwater Regulations. These regulations will govern where applicable. In accordance with the MSH the project is considered a redevelopment, which allows some of the MassDEP standards to be met to the maximum extent practicable. The comments below correlate with the MSH standards and where the more stringent Town requirements are applicable additional comments are noted. 1. Standard 1 states that no new stormwater conveyances may cause erosion in wetlands of the Commonwealth. a. The existing site currently sheet flows in three directions: • West from the Project site into an existing catch basin that appears to be associated with the drainage system in Osgood Street, also known as Rte 125, a Massachusetts State Highway; • Northwest towards an existing low point at the property boundary; and • Southwest towards the unnamed stream and BVW delineated at the edge of the existing parking lot. The Applicant is intending to maintain these three discharge points and has proposed best management practices (BMPs) to provide additional treatment. To verify that the proposed grass swale located along the southwest property line will not cause erosion at the existing headwall HW recommends that the Applicant provide the velocity calculations for the grass swale. 2. Standard 2 requires that post-development runoff does not exceed pre-development runoff off-site, for a redevelopment project per MassDEP this standard must be met to the maximum extent practicable. The Applicant has reduced impervious cover to all three discharge points and the HydroCAD modeling calculations provided indicate that the post-development peak discharge rates do not exceed the pre-development discharge rates. The proposed HydroCAD model does not include the proposed BMPs, including the rain gardens and grass swales proposed for water quality treatment. This is a reasonable methodology to verify compliance with Standard 2. HW has the following comments regarding the HydroCAD model: a. The Existing and Proposed Watershed Plans indicate that the existing building has specific breaks in the roof runoff. HW recommends that the Applicant provide a narrative explaining how the roof divide was determined. I I iC,18,1111111a8 ti) ml l. �,h!mww �m P' ,d� � o1") ..„ �p ..,il.I„.i, ;uIINTo,im � tl..W w r Town of North Andover May 2, 2018 Page 3of5 b. In accordance with Section 7.2 B. b) of the Stormwater Regulations the Applicant has provided the analysis for the 2-, 10-1 25-, and 100-year storm events and has utilized the 24 hour rainfall amounts as required per the Town of North Andover. c. Furthermore, in accordance with Section 7.2 B. b) of the Stormwater Regulations the Applicant should provide the analyses for the 1/2 inch storm. HW recommends that the Applicant provide these additional calculations. 3. Standard 3 requires that the annual recharge from post-development shall approximate annual recharge from pre-development conditions. a. In accordance with the MassDEP Standards the Applicant is required to meet Standard 3 to the maximum extent practicable. By reducing impervious area the Applicant believes it has met this Standard. b. In accordance with Section 7.2 C. d) of the Stormwater Regulations the Planning Board may alter or eliminate the recharge volume requirement if the site is in an urban redevelopment area. The Applicant has provided soil test pits noting that the estimated seasonal high ground water (ESHGW) prevents it from providing infiltration; however the Applicant has provided non-structural practices including filter strips and grass channels as required in the Stormwater Regulations. c. It appears that the Applicant is in compliance with Standard 3. 4. Standard 4 requires that the stormwater system be designed to remove 80% Total Suspended Solids (TSS) and to treat 0.5-inch of volume from the impervious area for water quality. a. The Applicant has utilized rain gardens with pea stone diaphragms for pretreatment to provide the 80% TSS removal. b. In accordance with Section 7.2 D. b) and c) of the Stormwater Regulations the Applicant should provide the water quality volume for the Y2 inch storm, however it appears that the Applicant has not provided sizing calculations for the rain gardens or provided the 1/2 inch storm analysis. HW recommends that the Applicant provided the sizing calculations for the rain gardens in accordance with Volume 2, Chapter 2, page 26 of the MSH. c. HW recommends that the Applicant provide a detail for the pea stone diaphragm. 5. Standard 5 is related to projects with a Land Use of Higher Potential Pollutant Loads (LUHPPL). a. The Applicant has noted that the proposed land use is not considered a LUHPPL; however the Layout & Materials Plan indicates that open storage bins are proposed. HW recommends that the Applicant clarify the proposed use of the property as well as document what material will be placed in the storage bins. 6. Standard 6 is related to projects with stormwater discharging into a critical area, a Zone II or an Interim Wellhead Protection Area of a public water supply. a. Standard 6 is not applicable to this site. 7. Standard 7 is related to projects considered Redevelopment. .,II. m r��;"h„ h ';mr�i 1 �'�III 1.�.......m, i�i� I, , dl�, S it �-, �i��is fi� ry,.....;i�" a I�m ..,il.. �i�St l,-1 „,.:� ol��,�,,„'u �i� I�'� I'w��I�IV"� h dl��h! �� „��"�,P ,, ��l�� 16��'� �' u�,m�� , mpg h"�" �,I�'un IN�'�III�� tll W�;�Iw'��. '.ar._...�� . .:�� ul� M.� � �I�mail..��I w � m m I�� ...� I��.:� � ... r.„ ...� �� '.��. ��.m. IIL�.. .... .�..�: �m I„I� ..�..r.,��... .�....�. Town of North Andover May 2, 2018 Page 4of5 a. In accordance with Section 7.2 E of the Stormwater Regulations and Volume 1, Chapter 1, page 2, of the MSH a redevelopment project is required to meet the following Stormwater Management Standards only to the maximum extent practicable: Standard 2, Standard 3, and the pretreatment and structural best management practice requirements of Standards 4, 5, and 6. Existing stormwater discharges shall comply with Standard 1 only to the maximum extent practicable. A redevelopment project shall also comply with all other requirements of the Stormwater Management Standards and improve existing conditions. The Applicant has designed the project to meet the MassDEP Standards to the maximum extent practicable and has improved existing conditions by reducing impervious cover and installing rain gardens for water quality treatment. As noted previously HW recommends that the Applicant provide sizing calculations for the rain gardens. 8. Standard 8 requires a plan to control construction related impacts including erosion, sedimentation or other pollutant sources. a. The Applicant has included a Site Preparation Plan and Erosion and Sediment Control Notes in accordance with Standard 8. The Applicant has noted on page 1-7 of the Drainage Report that the Stormwater Pollution Prevention Plan (SWPPP) will be prepared and submitted prior to construction. b. In accordance with Section 8.0 of the Stormwater Regulations, if a SWPPP is required per the NPDES General Permit the Applicant is required to submit a complete copy of the SWPPP as part of its application for a Land Disturbance Permit. HW recommends that the Applicant provided the SWPPP to the Town for review and verify that the Erosion and Sediment Control Criteria listed under Section 8.2 of the Stormwater Regulations is clearly referenced. c. HW recommends that the size of the Fiber Roll be added to Detail 7 on Sheet C-501. Furthermore HW recommends that the size of the siltation fence be added to the detail. 9. Standard 9 requires a Long Term Operation and Maintenance (O & M) Plan to be provided. a. The Applicant has included an O&M Plan in accordance with Standard 9. HW recommends that the Applicant provide additional information related to the maintenance of the grass swale and pea stone diaphragm. Furthermore the Applicant may choose to separate the narrative for the bioretention area and the grass channel so that the plants in the rain gardens are not mowed. 10. Standard 10 requires an Illicit Discharge Compliance Statement to be provided. a. The Applicant has stated that an illicit discharge statement signed by the property owner will be provided prior to the discharge of any stormwater. 11. 25 foot No Disturb Zone a. The Applicant is proposing the removal of asphalt along the southwest property boundary. The removal of impervious cover is strongly encouraged however a portion of this asphalt is on the abutting parcel, permission from the property owner will be required as well as an Order of Conditions from the Conservation Commission. �I. .. h„A.�:1 8'1 u 8 �.I 1� � �ma il.dl 0 1hI.m 1,1, m m I�� „.��. I�. � , ,dl. S �� 16i o.; II 8 .... Iw'..r., ... .�..... Town of North Andover May 2, 2018 Page 5 of 5 12. Low Impact Development a. The Applicant has proposed reducing impervious cover, installing rain gardens and grass channel. The proposed stormwater practices are considered low impact development in accordance with the MSH. 13. Miscellaneous Comments: a. The proposed plan set including the Layout & Materials Plan, the Grading & Drainage Plan, and the Utilities Plan illustrate subsurface trenches in the area of the existing catch basin and Bioretention Area #2. It is not clear what these trenches are. HW recommends that the Applicant clarify the purpose of these trenches. b. As noted previously Osgood Street is a state highway and the Applicant is discharging stormwater into the state drainage system. HW recommends that the Applicant document to the Planning Board that permission to continue to discharge into the Massachusetts Department of Transportation (MassDOT) drainage network will be received prior to construction. The Applicant is reducing the flow to this catch basin as well as providing water quality as will be required by MassDOT. Conclusions HW recommends that the Planning Board require that the Applicant address these comments as part of the Board's review process. The Applicant is advised that provision of these comments does not relieve him/her of the responsibility to comply with all Town of North Andover Codes and By-Laws, Commonwealth of Massachusetts laws, and federal regulations as applicable to this project. Please contact Janet Bernardo at 857-263-8193 or at jbernardo@horsleywitten.com if you have any questions regarding these comments. Sincerely, HORSLEY WITTEN GROUP, INC. Janet Carter Bernardo, P.E. Senior Project Manager ., d V,� q'-A, I'll", r9 .,,ii I..,�,.,,... ."' .. it".,.. 7,"i��i,. , i,,,. .,II.,�� .n. ro 1 1........m,w V��; I, '' � d11 rt;�it �i'i is fi� ry.,......, ��,�u''n I w „� m� �..,il...,. s,II T .-�„��,. �,tl,;„„u ,iIV, � h! ��,PG �� 6 �� m � N-��ilm tllW,,Iw .ar._...� �. .:�� ul� M.� � �I�mail.�.��I w � m� I�� ...� I��.:� �... r.„ ... �� '.��. ��.m. IIL�.. III....III.�..�: �m I„I ..�..r..,��... .�....�.