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2020.03.26 Staff ReportTo: Conservation Commission From: Sarah LaValley RE: Staff Report, March 26, 2020 Commission Meeting _______________________________________________________________ 5:30 PM – Notice of Intent for construction of a dock and wooden staircase. Work proposed within riverfront area, bank, and land subject to flooding (CT River). Tyson Holub & Alexis Neubert. 142 Riverbank Rd, Map ID 25-007. Application Overview: Work proposed is construction of a 12’x12’ seasonal floating anchored dock and stairs on bank to the Connecticut River, and a 12x14 foot wooden patio. The Commission has previously reviewed a septic reconstruction and construction of an 8’ x 12’ deck on the rear of the property that had already been constructed, in absence of building permits. A negative determination was issued since the deck sits on six concrete posts, approximately 2’ above ground level. Demolition of a dilapidated garage was also permitted. DEP Comments: [1] The commission needs to wait to close the public hearing until NHESP issues its decision. NHESP has issued a ‘no-take’ determination, with no additional comment. [2] For the work in the riverfront, the commission can require an improvement over existing conditions. Acceptable improvements include, but are not limited to: 1) Significant net reduction of impervious surfaces; 2) Planting of indigenous plant species; 3) Removal and proper disposal of noxious but otherwise legally located materials. Staff agrees, an improvement should be required. The revised planset includes six red osier dogwood plantings along the top of bank. The Commission should discuss whether joint plantings on the bank were considered in addition. Consistency with the WPA and Northampton Wetlands Ordinance: The application is presented as a limited project water dependent use pursuant to 310 CMR 10.24(7), for which the work qualifies, and work within the Protected Zone may be allowed pursuant to this provision. Under the limited project provisions of the WPA, the Commission can issue an Order notwithstanding performance standards for those resource areas. The overall minimal disturbance of the dock and stairs appear to have been designed to protect the riverfront resource area. BLSF requirements still apply. The application does not clearly indicate the cubic volume of flood storage affected by the overall project. The Commission should clarify this with the applicant. The work may constitute less than 1 cubic yard of fill in BLSF, under which the Commission has previously determined does not constitute an alteration. Staff Recommendations: The bank is extremely steep, as shown in photos, and the Commission should discuss detailed construction plans with the applicant. These were not added to the revised application. If the Commisison agrees that the work constitutes an overall improvement, an Order of Conditions, with standard conditions, can be issued. Assessment of the plantings, and replacement of any dead plantings, shall be required prior to issuance of a certificate of compliance. 5:45 PM: Notice of Intent for paving and roadway drainage improvements. Work to take place in bank, riverfront area, and bordering land subject to flooding (Mill and Manhan Rivers). Northampton DPW, Meadow Street and Loudville Road ROWs Application Overview: The application proposes repaving of Loudville Road and Meadow Street. Drainage improvements to direct water off of paved surfaces are also proposed, including subdrain, replacement of a catch basin inlet and drainage culvert, and creation of crushed stone shoulders along Loudville Road, and replacement of a catchbasin, creation of crushed stone shoulders, sidewalk replacement, parking spaces and infiltration trenches along Meadow Street. Consistency with the WPA and Northampton Wetlands Ordinance: The application includes an assessment, beginning on page 6, of compliance with applicable performance standards with which staff concurs. Much of the described work is exempt or is covered under the DPW’s generic Order of Conditions, as discussed on page 5, and the remainder qualifies as a limited project, with work allowed in Protected Zones, including addition of stone to bank, under the Wetlands Ordinance. Work is proposed within Priority Habitat of Rare and Endangered Species, but should be qualify as fully exempt from review. DEP Comments: A file number has not yet been issued; staff expect very minor comment due to the limited scope of the project and exempt status of much of the work. Staff Recommendations: Work is needed to maintain roadway safety and involves very limited wetland resource disturbance. Most of the work proposed will constitute an improvement over existing conditions by reducing erosion and creating some level of pretreatment. An Order of Conditions, with standard conditions, can be issued. 6:00 PM:Notice of Intent for replacement of an existing stormwater pipe, abandonment of an existing point-source stormwater discharge to Broad Brook, creation of a new stormwater discharge, and pedestrian path culvert replacement. Northampton DPW, North Farms Road ROW and map IDs 07-035 and 07-042. Application Overview: As part of a larger North Farms Road improvement project, the application proposes stormwaterimprovements and rerouting to address existing ponding and deterioration concerns in two locations. The first is replacement of a crushed 12” pipe that carries roadway runoff under a private farm field to a wetland area. This pipe is undersized and is not sufficient to handle existing flows; a 24” concrete/high density polyethelene (HDPE) pipe is proposed. The flow capacity of the pipe will increase  from the current 6cfs to a proposed 18cfs during a 2-yr, 24-hour storm. Actual flow volumes will vary depending upon each particular storm event. The second project, developed in cooperation with staff, is relocation of an existing 15” drain that discharges directly into Broad Brook without treatment, and causes periodic flooding during large events since it is undersized. Drainage is proposed to be redirected to a forested wetland with the Broad Brook Greenway via a 24” outfall. This will result in increased flows to the wetland, which connects to Fitzgerald Lake via a 15” pipe under the pedestrian walkway. Also included in the project is replacement of the pipe with a four foot buried box culvert. This project is in line with City ‘design with nature’ goals to increase natural storm and flood storage capacity where possible, eliminate direct piped discharges, and increase treatment and infiltration. DEP Comments: For site 1, it states... "Impacts to Land Under Water – A scour pool currently exists at the pipe outfall. A 42 sf stone pipe end is proposed at the outfall to reduce erosion during storm events; no changes to the existing contours are proposed in this area". Both the WPA and 314 CMR 9.00 prohibit the discharge of stormwater directly into Waters of the United States. There must be a setback from the receiving water.Staff agrees. The Commission should require a revised planset that pulls back the proposed discharge completely from the resource area and eliminates permanent BVW and LUW impacts in this area. The Commission will need to discuss how any foreseen erosion or scour resulting from overland flow will be addressed as a result of this shift. Consistency with the WPA and Northampton Wetlands Ordinance:The application includes an assessment of impacts and alternatives. Work qualifies as a Limited Project, as noted. Except for the note in DEP comments, staff agrees that impacts, primarily temporary, will result in overall improvements to stormwater quality by increasing treatment, reducing scour and erosion, and shifting outfalls from direct discharge points. Staff Recommendations: Once above issues are finalized, issue an Order of Conditions with standard conditions. Discuss construction impacts and methods related to the culvert installation, along with ways to minimize recreational impacts. An information signage about the environmental benefits of the project could be suggested as a way to increase knowledge and discussion about the benefits of green stormwater methodology.