Loading...
10-4-22 Final ReportRobert E. Mellstrom, P.E. 10 Maple Street Plainfield, MA 01070 413 634-2182 bob.mellstrom@gmail.com October 4, 2022 Dan Desmond The Ice Pond Association 49 Ice Pond Drive Florence, MA 01062 Re: Fall 2022 Inspection Report for the Ice Pond Storm Water Management System, Ice Pond Subdivision, Northampton, Massachusetts Dear Dan, The following is my engineering report on the operation and maintenance of the Storm Water Management System for the Ice Pond Subdivision, located off Rocky Hill Road (Rt. 66), adjacent to and west of the Hampshire County Jail. This letter report is based on discussions with you and my field observations and inspection of Storm Water management facilities on September 20, 2022. SYSTEM DESCRIPTION The Storm Water Management System consists of the following: Two Stormceptor® treatment structures, model No. STC 450, “Inlet” design. Stormceptor® number 1 is in the driveway to No. 19 and No. 23 Ice Pond Drive and Stormceptor® number 2 is located in the driveway to No. 55 Ice Pond Drive. All collected storm water from the 6 Ice Pond Drive catch basins flows through one of these structures. These structures are designed to separate floatables and suspended solids from storm water flow for periodic collection and proper disposal; thereby, removing such materials from the storm water runoff. Two Level Lip Spreaders. Spreader 1 is located on Lot No. 27 behind house number 23 and Spreader 2 is located on Lot No. 28 behind house number 55. Flow from each Stormceptor® is piped to a Spreader. The Spreaders are designed to collect sediments, act as a detention basin, allow infiltration and distribute overflow equally over the length of the spreader; thereby avoiding concentrated runoff. Ice Pond Detention Basin. The former Ice Pond, which is now drained, once provided ice for the nearby State facilities is located east of Ice Pond Drive and north of Rocky Hill Road. The Ice Pond Drive Subdivision is within a larger watershed area that flows to the Ice Pond basin. The Ice Pond Association now has the responsibility for maintaining two existing Ice Pond structures: the lower debris rack and outlet structure and the upper overflow structure. These structures are located on Lot No. 29 on the north side of Rocky Hill Road, Rt. 66. During heavy runoff events, runoff to the Ice Pond may back-up and fill the pond area which acts as a very large detention basin. Under extreme flow conditions, the water level could reach the overflow structure. Normally, runoff to the Ice Pond enters a culvert at the outlet structure which passes under Rocky Hill Road, with no back-up. STORM WATER SYSTEM OPERATION and MAINTENANCE Stormceptor® Treatment Chambers. Both treatment chambers were clean on the inside. Using a “sludge stick”, my inspection on September 20, 2022, revealed ≈ 1” of sediment in a 5 foot sump in Stormceptor® No.1 and ≈ 11” of sediment in a 4’-11” sump in Stormceptor® No. 2. Please note that the screens had been previously removed to prevent clogging and allow for the collection of more sediment. These structures are operating properly as indicated by the lack of sediment and debris in the Level Lip Spreaders. I recommend that Stormceptor® No. 2 be cleaned with a vacuum truck to remove all accumulated sediment. Stormceptor® No.1does not require cleaning at this time. These structures should be inspected yearly and cleaned as necessary. Maintenance; however, should be performed immediately after an oil spill. Inspection and cleaning of catch basins is also an important part of storm water system maintenance and should be performed yearly and cleaned as necessary. It is my understanding that cleaning of the catch basins is the responsibility of the City of Northampton. Level Lip Spreaders. Both of the Spreaders are in good condition and well maintained. Growth within the spreaders was recently cut and removed. It is recommended that this continues annually, after the growing season in the fall. No noticeable sediment or debris has accumulated in the spreaders, which is an indication that the Catch Basins and Stormceptors® are operating properly. If any accumulation occurs, it should be removed annually and properly disposed. Ice Pond Debris Rack and Outlet Structure. The Debris Rack is clear of debris and flow in the brook was entering the culvert without back-up. The Association has an agreement with their Landscaper to clean the Debris Rack monthly and after significant rainfall events which should continue. Ice Pond Overflow Structure. This structure appears to be operating properly and the grate covering the opening is secure. This structure is also inspected monthly. The next inspection is anticipated in the fall of 2023. Attached are photos of the Storm Water management structures taken during the field inspection on September 20, 2022. Should there be any questions, please contact me at the address listed above. Respectfully Submitted, Robert E. Mellstrom P.E.