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Home My WebLink AboutConsultant Review - 196 MAIN STREET 1/16/1998 TO: Kathleen Bradley Colwell, Town Planfr , FROM: James Rand, Jr. Dir. of Engineering h DATE: January 16, 1998 SUBJECT: ST. MICHAEL'S PARISH SITE PLAN .-E' ,....�ave.�_ The site plan provided is pictorial only. It shows the existing conditions and the proposed changes to the site. However, no hard data such as hydrology, proposed grades, etc. are shown. Therefore, we cannot give a definitive review at this time. , I did meet with Mr. William MacLeod of Andover Consultants the engineer for the project and Mr. Angelo Petrozzelli of Design Partnership Architects, Inc. the architect for the project. Mr. MacLeod informed me that his firm was in the process of completing the site plan with finish grades and the hydrology for the site. Mr. MacLeod indicated that this data would be available in a couple of weeks. Both gentlemen stressed the fact that there would be a net reduction of impervious area on both the school and church sites, as outlined in the project narrative attached. This net reduction should preclude there being any adverse effects on the Town's existing drainage systems. Nor should there be any adverse deviations in surface flow characteristics. While a final review cannot be made at this time. The fact that a significant reduction in impervious material is to be made would indicate that we should not encounter drainage problems. CC:J. William Hmurciak M. Howard Consv. Administrator C:WMIPR0\STMIKES\REVIEW1 DEPARTMENT OF PUBLIC WORKS TOWN OF NORTH ANDOVER 384 Osgood Street, North Andover, Massachuse �— w w tel. 978-683-0950 fax 978-69 FA-N 4 LETTER � HAIA-k c ®® DATE: JANUARY 30, 1998 SENT BY: JAMES RAND, TO: DAVID R. JOHNSON, P.E.,P.L.S. NUMBER OF PAGES: 1 COMPANY: ANDOVER CONSULTANTS, INC. 1 EAST RIVER PLACE METHUEN, MASSACHUSETTS 01844 TEL 978-687-3828 FAX 978-686-5100 DEAR MR. JORDAN: I AM IN RECEIPT OF YOUR LETTER DATED JANUARY 28, 1998, REGARDING ST. MICHAEL'S PARISH/SCHOOL SITE. UNFORTUNATELY THE RESULTS OF YOUR STORMWATER STUDY SHOWS THAT THERE WILL BE A INCREASE IN RUNOFF AS OPPOSED TO A NET DECREASE AS ANTICIPATED BY ALL CONCERNED PARTIES, WHILE THE OVERALL NET INCREASE IS 6000 SQUARE FEET,THE TOTAL INCREASE ON THE SCHOOL SITE IS 13,000 SQUARE FEET. THIS SQUARE FOOTAGE, SINCE IT IS ON A PORTION OF THE 6.28 ACRES WILL HAVE A GREATER PERCENTAGE INCREASE THAN 2%. WHILE I AGREE WITH YOU THAT THE INCREASE MAY NOT BE SIGNIFICANT,IT IS AN INCREASE. THEREFORE,WE MUST ADDRESS THIS ISSUE AS WE WOULD ON ANY SITE SEEKING TOWN APPROVAL. PLEASE REFERENCE THE"STORMWATER DRAINAGE" SECTION OF THE SITE PLAN REVIEW REQUIREMENTS,OF THE TOWN OF NORTH ANDOVER. ALSO I WOULD INFORM YOU THAT THIS DEPARTMENT DOES NOT HAVE IN ITS POSSESSION COPIES OF THE PLANS REFERENCED IN YOUR LETTER. IF YOU WOULD INCLUDE THEM WITH YOUR CALCULATIONS AND ANY ADDITIONAL DESIGN FEATURES NEEDED, IT WOULD EXPEDITE OUR REVIEW. IF YOU HAVE ANY QUESTIONS PLEASE CALL. I LOOK FORWARD TO WORKING WITH YOU ON THIS PROJECT, CC: J. WILLIAM HMURCIAK KATHLEEN BRADLEY °' MICHAEL HOWARD ANGELO PETROZZELLI arldover consultants Fac Peer Piece inc. Massachusetts 01844 I (508) 687-3828 January 28, 1998 Mr. James Rand Jr. Director of Engineering Division of Public Works Town of North Andover 384 Osgood Street North Andover, MA 01845 Re: St. Michael's Parish/School 196 Main Street Dear Mr. Rand: I have examined the plans for St. Michael's Parish to determine what impact the proposed development will have on the stormwater runoff that leaves the project site. For existing conditions, I used a plan entitled "Topographic Survey of Land in North Andover, Mass." prepared for St. Michael's Parish, dated December 18, 1997, by Andover Consultants, Inc. For the proposed conditions, I used a plan entitled "Site Plan" St. Michael's Parish, North Andover, Mass., sheet X-1, dated 12-18-97, latest revision 01-22-98, by Design Partnership Architects. Based upon the information on those two plans, I found the following: • There will be an increase in the impervious surface on the school site of approximately 13, 000 square feet. • The runoff curve number for the school site will increase from 91 under existing conditions to 94 for proposed conditions. • The time of concentration and overall runoff patterns for the school site will not change. • There will be a decrease in the impervious surface on the church site of approximately 7000 square feet. • The runoff curve number for the church site will decrease from 87 for existing conditions to 85 for proposed conditions. • The time of concentration and runoff patterns for the church site will not change. • Overall, there will be a net increase in impervious surface of approximately 6000 square feet. Civil Engineers • Land Surveyors 9 Land Planners andover consultants inc. Re: Mr. James Rand Jr. St. Michael's Parish/School Page 2 The net increase in impervious cover of 6000 square feet compared to the total site area of 6.28 acres is only an increase of 2%. It is my professional opinion that proposed construction on these sites will not have a significant impact upon the stormwater runoff rates in the area. If you have any questions, do not hesitate to give me a call. Sincerely, ANDOVER CONSULTANTS INC. David R. Jordan, P.E., P.L.S. Vice President DRJ/en TO: Kathleen Bradley Colwell, Town Plann r ,, FROM: James Rand, Jr. Dir, of Engineering DATE: February 10, 1998 SUBJECT: ST. MICHAEL'S PARISH SITE PLAN REVIEW NO 2 ! � After reviewing new topographic site plans, meeting with Mr. David Jordan, P.E. of Andover Consultants Inc. and data outlined in Mr. Jordan's' letter dated February 6, 1998 this department is satisfied with the conclusions. There will be no increase in runoff rates and after construction there will be a net decrease in runoff. We are satisfied with their compliance of the storm drainage section of the Site Plan Review requirements of the Town of North Andover. The plan referenced in this memo is "Topographic Survey of Land in North Andover, Mass. Prepared for St. Michael's Parish Date: December 18, 1997 Scale: 1" = 40"'. Enc. CC:J. William Hmurciak, P.E., Dir, of DPW M. Howard Conservation. Administrator David R. Jordan, P.E. Andover Consultants CAAMIPR0\STMIKES\REVIEW2 andever consultants 1 East River Place Inc. Methuen, Massachusetts 01844 I (508) 687-3828 February 6, 1998 Mr. James Rand Jr. Director of Engineering Division of Public Works Town of North Andover 384 Osgood Street North Andover, MA 01845 Re: St. Michael's School Dear Mr. Rand: This office has completed the site plan for the proposed addition to St. Michael's school, a copy of which is being sent to your office. The final design addresses your concerns about the slight increase in runoff that was originally contemplated in my letter to you dated January 28, 1998. We have eliminated the increase in runoff by making the following changes to the final site plan dated February 5, 1998: • Approximately 18,000 square feet of existing pavement around the school will be removed so that after construction of the proposed addition (including the future gymnasium), the total impervious area on the site will be the same as currently exists. • Two new dry-well catch basins will be installed, one opposite the new entrance to the school, and one in the northeast corner of the new parking area. • The existing time of concentration and overall runoff patterns for the site will not change after construction. While the proposed dry-well catch basins do have outlet pipes connecting them to the on- site closed drainage system, these have been provided as an overflow prevention measure for large storms. Given the nature of the underlying soils (fine sandy loams), it is expected that all of the runoff from most rainfall events will leach out of the dry-wells. In conclusion, the final design of the St. Michael's School site will not result in increase in the stormwater runoff rates leaving the site. In fact, with the addition of the two dry-well catch basins, there will be a net decrease in the runoff after construction. This exceeds the standards of the stormwater drainage section of the Site Plan Review requirements. andover consultants inc. Included with this letter is a copy of a plan entitled "Topographic Survey of Land in North Andover, Mass." prepared for St. Michael's Parish, dated December 18, 1997. This is the plan that was used to determine the existing conditions on the site. If you have any questions, do not hesitate to give me a call. Sincerely, ANDOVER CONSULTANTS, INC. David R. Jordan, P.E., P.L.S. Vice President