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Home My WebLink About2013-03-05 Planning Board Supplemental Materials (32) February 27, 2013 Ms. Judith Tymon North Andover Town Planner 1600 Osgood Street North Andover, MA 01845 Re: Regency Place PRD, 464 Appleton St. North Andover Engineering Department Subdivision Review #2 Dear Ms. Tymon: We have received a copy of Gene Willis’ February 6, 2013 Subdivision Review #2 for the above referenced project, and we offer the following response. To facilitate the review of this information, we have reproduced each of Mr. Willis’ comments in Italics, and our response to each comment immediately follows. 1. The development utilizes many low impact development (LID) techniques that require drainage easements outside of the right of way. The DPW does not have personnel to maintain these facilities. A homeowners association should be created to maintain the drainage, both inside and outside the right of way, in perpetuity. There should be reference to the association in the individual lot deeds. CSI response: The Subdivision Plans and the Stormwater Management Operation and Maintenance Plan (O&M Plan) will be revised to reflect the requirement that a Homeowners Association (HOA) will be established to maintain Infiltration Basins A and B. The O&M Plan already states that the owner of each lot will also be responsible for the maintenance of the grass swale and driveway culvert on and in front of his/her lot. Appropriate deed restrictions will be placed on the lots. We disagree that the HOA should maintain the drainage system components that will lie in the roadway right-of-way. The Low Impact design results in far less roadway infrastructure for the Town to maintain, and the stormwater design includes just two catch basins and a Stormceptor that will require routine maintenance. One existing catch basin that the Town currently maintains will be eliminated. Only about 5,500 square feet of new roadway pavement will contribute to the two catch basins and Stormceptor. The cost of inspecting and removing the sediment from these devices should be far less than the cost of maintaining the drainage system from a convention roadway design. The taxes to be paid by the homeowners should cover CHRISTIANSEN & SERGI, INC. PROFESSIONAL ENGINEERS AND LAND SURVEYORS 160 SUMMER STREET, HAVERHILL, MA 01830 tel: 978-373-0310 www.csi-engr.com fax 978-372-3960 z Page 2 the cost of the Town maintaining the drainage system from a small portion of the road. 2. Much of the drainage infrastructure/swales as shown will be located on private property. Easements should be created to describe the areas (swales, basins, structures etc.) and granted to the homeowners association. Specifically infiltration basins C & D are not delineated with bearings and distances. CSI response: Infiltration Basins C and D will be installed to mitigate peak rates and treat runoff from the driveways of Lots 3 and 4, respectively. Since each of these basins will only receive runoff from the lot on which it lies, it will be the responsibility of the individual homeowner, and not the HOA, to maintain the basin on his/her lot. No easements are necessary since no entity other than the homeowner (or his/her agents) will need access to the basins. Appropriate deed restrictions will outline the requirements for perpetual maintenance. 3. The project proposes using a “Stormceptor” to replace the existing catch basin at STA. 0+23.6. The DPW does not have personnel to maintain this type of infrastructure. This structure, and the two up gradient catch basins at STA. 0+37.5, should remain the responsibility of the homeowner’s association referenced above. CSI response: Maintenance of the Stormceptor device is similar to catch basin maintenance. Inspections are made by opening the cover and measuring the depth of sediment from the surface, and cleaning takes place using a vacuum truck. We have attached a copy of the Stormceptor maintenance brochure for further information. 4. An O&M plan for the LID facilities should be created and incorporated in the home owner’s association. The association should be referenced in the individual lot deeds. a. The operation and maintenance of the entire drainage system listed in the Stormwater Report will remain a private responsibility in perpetuity. b. The Board’s decision should reflect this fact preferably with deed restrictions on the individual lots. CSI response: The recorded HOA documents will include reference to the approved O&M Plan, and the individual deeds will reference the HOA. We again disagree that the HOA should maintain the drainage system components that will lie within the Town accepted right-of-way. z Page 3 5. The DPW does not require the newly created subdivision road to be a through street to the existing Appleton St. roadway. CSI response: No response necessary. 6. The proposed new roadway entrance should leave Blue Ridge Road with a negative pitch. The low point in the roadway pavement should occur opposite the catch basins at STA. 0+37.5. CSI response: Though the proposed roadway centerline will leave Blue Ridge Road at a positive pitch, the two proposed catch basins will be set at elevations lower than the existing pavement in Blue Ridge Road (see roadway profile on Sheet 8 of the Plans), so runoff from the new road will not flow onto Blue Ridge Road. It should be noted that §6.8.9 of the Subdivision Regulations allows new subdivision roads to be constructed with grades of up to 3 percent upgradient or downgradient from the existing roadway. It is not reasonable to expect subdivisions where the land is at a higher elevation than the existing roadway to have a roadway starting with a downhill grade. The current design is consistent with the applicable regulations. 7. Section 6.9 curbing waiver request. The width of the roadbed subgrade and gravel fill must extend the full 32 feet wide (4’ at each shoulder) if the granite curbing is to be waived. CSI response: The “Subdivision Street with Drainage Swales” detail provided on Sheet 10 of the Plans is consistent with this request, in that it indicates that the sub base and gravel are to extend 4 feet beyond the edge of pavement on both sides of the road. 8. A detail should be provided for water and sewer service connections. CSI response: The plans will be revised to include the water and sewer service connection details. 9. Particular attention must be paid to the grass seed mix proposed for the swales. Should check dams be installed in the steeper sections of the shoulder drainage swale? CSI response: The applicant intends to install sod in the swales as soon as the roadway binder pavement is installed. This will provide immediate stabilization and will allow the grass to provide filtration for the runoff much sooner than would occur if seed were used. The “Subdivision Street with Drainage Swales” detail provided on Sheet 10 of the Plans will be revised to specify sod in place of loam and seed. Temporary checks dams will be maintained in the drainage swales during construction (see Sheet 9 of the Plans). Due to the limited drainage areas and low velocities of flow expected in the swales, permanent check dams are not needed (see attached Analysis of Drainage Swale Hydraulics). 10. All accumulated sediment shall be removed from infiltration basins before roadways are submitted to the town for acceptance. CSI response: The Subdivision Plans and the Stormwater Management O&M Plan will be revised to include the recommended notation. The Definitive Plans and Stormwater Management Report will be revised as noted to address the comments made by Mr. Willis, Eggleston Environmental, Hancock Associates, and comments received from other Town Departments. Please contact me if you have any questions regarding this matter. Very truly yours, Chri iansen & Sergi, Inc. *Phili.. 0 Page 4 Inspection and Maintenance. Easy. Convenient. When it rains, oils, sediment and other contaminants are captured and contained by over 20,000 Stormceptor units operating worldwide. While Stormceptor’s patented scour prevention technology ensures captured pollutants remain in the unit during all rainfall events, the accumulated pollutants must eventually be removed as part of a regular maintenance program. If neglected, oil and sediment gradually build up and diminish any BMP’s efﬁ ciency, harming the environment and leaving owners and operators vulnerable to ﬁ nes, surcharges and bad publicity. Maintenance is a must Ease, frequency and cost of maintenance are often overlooked by speciﬁ ers when considering the merits of a stormwater treatment system. In reality, maintenance is fundamental to the long-term performance of any stormwater quality treatment device. While regular maintenance is crucial, it shouldn’t be complicated. An ongoing maintenance program with Stormceptor is convenient and practically effortless. With virtually no disruptions, you can concentrate on your core business. Quick inspections Inspections are easily carried out above ground from any standard surface access cover through a visual inspection of the oriﬁ ce and drop tee components. A sludge judge and oil dip-stick are all that are needed for sediment and oil depth measurements. Easy unit access Maintenance is typically conducted from the same surface access cover, eliminating the need for conﬁ ned space entry into the unit. Your site remains undisturbed, saving you time and money. MAINTENANCE Maintenance_imbrium.indd 1 5/2/2007 8:58:38 AM No muss, no fuss and fast Maintenance is performed quickly and inexpensively with a standard vacuum truck. Servicing usually takes less than two hours, with no disruption to your site. A complete stormwater management plan for Stormceptor extends beyond installation and performance to regular maintenance. It’s the smart, cost-effective way to ensure your unit continues to remove more pollutants than any other separator for decades to come. Stormceptor maintenance recommendations Units should be inspected post-construction, prior to being put into service. Inspect every six months for the ﬁ rst year of operation to determine the oil and sediment accumulation rate. In subsequent years, inspections can be based on ﬁ rst-year observations or local requirements. Cleaning is required once the sediment depth reaches 15% of storage capacity, (generally taking one year or longer). Local regulations for maintenance frequency may vary. Inspect the unit immediately after an oil, fuel or chemical spill. A licensed waste management company should remove captured petroleum waste products from any oil, chemical or fuel spills and dispose responsibly. With over 20,000 units operating worldwide, Stormceptor performs and protects every day, in every storm. • • • • • • www.imbriumsystems.com USA: (888) 279 8826 CANADA: (800) 565 4801 Maintenance_imbrium.indd 2 5/2/2007 8:58:49 AM