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24D-021 NCC_emergency request_2014.pdfCITY OF NORTHAMPTON, MASSACHUSETTS DEPARTMENT OF PUBLIC WORKS 125 Locust Street Northampton, MA 01060 413-587-1570 Fax 413-587-1576 Edward S. Huntley, P.E. Director Pg.1/1, M:\King Street Brook\Permitting\NCC\Memo_nls_NCC_emergency request_05292014-1.docx Memorandum To: Northampton Conservation Commission From: James R. Laurila, P.E. City Engineer Nicole Sanford, Sr. Environmental Scientist Date: June 3, 2014 Re: Request for Emergency Order of Conditions for Debris Removal from King Street Brook Channel The City of Northampton Department of Public Works (DPW) requests that the Northampton Conservation Commission (NCC) issue an Emergency Order of Conditions pursuant to the Massachusetts Wetlands Protection Act and the Northampton Wetlands Ordinance for the removal of woody debris and four (4) beaver deceivers located within the King Street Brook near the Barrett Street Marsh Conservation Area in Northampton, Massachusetts. The area of concern is located upstream of the junction of the King Street Brook and the Northampton Bikeway (see enclosed figures). The existing beaver deceivers within the King Street Brook channel are clogged and are not properly functioning. Additionally, woody debris from past beaver activity is transported downstream during storm events and continues to clog the existing 4’x4’ box culvert underneath the Northampton Bikeway. On May 23, 2014, Northampton received 2.81 inches of rain within one hour. An existing beaver dam and woody debris within the King Street Brook channel resulted in a diversion of flow away from the culvert and Barrett Street Marsh Conservation Area resulting in significant flooding damage to personal property within the Church Street/State Street neighborhood. This diversion and damage to personal property occurs during significant rain events. Residents have reported 4-5 feet of flooding in basements resulting in structural damage to foundations, and damage to furnaces and hot water heaters. DPW is prepared to remove the four beaver deceivers by hand, but proposes to use a tracked excavator to remove the large woody debris piles that are located adjacent to the bank of King Street Brook and near the outlets of the sedimentation basin. The track excavator will result in approximately 950 SF of temporary impact to Bordering Vegetated Wetland. While the excavator is tracked and has low ground pressure (4.5 psi), the machine will be placed on construction mats while in the wetland. Other than the hand removal of the beaver deceivers, there will be no excavations associated with this emergency removal of woody debris. Erosion control barriers consisting of silt socks will be placed adjacent to the stream channel to function as limit of work and to prevent sediment from washing into the channel during debris removal. To prevent unnecessary soil disturbance in the wetland, the tracked excavator will remaining mostly stationary and the debris piles will be placed on top of the bike path and then loaded into a dump truck for removal. DPW will continue to remove sediment from both the King Street Brook Detention Basin and box culvert as allowed per the Generic Order of Conditions.