At their May 14 hearing, members of the Conservation Commission expressed a desire for an independent expert evaluation of how the proposed Kohl condo development off North Street (latest version) would impact the hydrology of the site. On July 8, the Commission issued the Request for Proposals shown below and has selected the proposal submitted by New England Environmental, also shown (or download it as a PDF). NEE’s report is scheduled to be discussed at a Conservation Commission hearing on Thursday, August 27, 6pm in the City Hall Hearing Room.
Request for Proposals (July 8, 2009)
Hydrological Review of a Proposed Condominium Project in the City of Northampton
For any questions contact Bruce Young, Land Use and Conservation Planner
Submit electronic responses to: BYoung@NorthamptonMA.gov
The City of Northampton Conservation Commission is seeking a qualified professional to conduct a review of a proposed condominium project, filed as a Notice of Intent under the Massachusetts Wetlands Protection Act and the City of Northampton Wetlands Ordinance, to determine whether or not the section of the proposed project located within the 100’ buffer zone of Bordering Vegetated Wetlands would adversely affect the hydrology of the adjacent Bordering Vegetated Wetlands.
The project information and area to be reviewed are shown on the site plans, Stormwater Drainage Report and Notice of Intent Application attached to this RFP:
- The consultant shall provide documentation of qualifications and a timeline for completion.
- The consultant shall review the Notice of Intent Application, Stormwater Drainage Report, Site Plans and any information developed by the consultant during site visits, but shall provide a determination based on the sections of the proposed project that are located within the 100’ buffer zone of the Bordering Vegetated Wetlands. The determination shall include surface water and groundwater interactions from the buffer zone to Bordering Vegetated Wetlands to the Bordering Vegetated Wetlands.
- The project should require minimal field work. A minimum of one site visit shall be scheduled with the Chair of the Northampton Conservation Commission.
- The consultant shall make determinations on the following proposals: 20 units with slab on grade and frost wall construction; and 20 units with typical basement and foundation wall construction.
- The consultant shall issue a report to the Northampton Conservation Commission detailing the hydrological review methodology and a determination of whether or not the proposed project will adversely impact the hydrology of the Bordering Vegetated Wetlands.
- The Consultant shall attend and participate in one City of Northampton Conservation Commission public hearing, and shall provide an oral report with appropriate public presentation aides and materials.
Watering-up: Studies of Groundwater Rising After Trees Cut
…”sites most susceptible to [hydrology] changes after clearcutting were the transition ones between the bogs or fens and the uplands.” This appears to describe well the land Kohl proposes to remove trees from. An average rise on the order of 20 cm (7.9 inches) in the water table is plausible. This could put unanticipated strains both on the foundations of the condos and on the stormwater mitigation system, a major component of which is underground. In addition, “the clear-cut of riparian and other wetland vegetation may lead to ecosystem conversion, i.e., to the encroachment…of water-tolerant or of shallow-rooted invasive species.” Conservation and Land Use Planner Bruce Young has shown a keen interest in controlling invasive species on Kohl’s land.
The phenomenon of groundwater rising after tree harvests is common enough to have its own term: “watering-up”…
Heat and Rain Increasing in Massachusetts: Implications for Infill and the Proposed Landfill Expansion
Video: Conservation Commission Meeting of 7/23/09; Barrett Street Marsh; Community Preservation Act Funds
July 23: Kohl Condo Proposal Goes Back Before the Conservation Commission; New Draft Covenants
Special Permit As Issued to Kohl Construction for North Street Condos
Video and Slides: Planning Board Grants Special Permit to Kohl Condos on 6/25/09
Latest Kohl Condo Proposal for North Street: 20 Units as Duplexes
Video: Planning Board Reviews the Latest Kohl Condo Proposal on 5/14/09
Video: Conservation Commission Reviews Latest Kohl Condo Proposal on 5/14/09
Kohl’s own test pit data (PDF, 735KB) shows areas along and south of Northern Avenue where removing existing fill (necessary to secure the condo foundations) would involve work below the level of seasonal high groundwater…
The potential impact to groundwater flows appeared to concern some members of the Conservation Commission, who called for an independent expert evaluation of how the proposed development would impact the hydrology of the site.
Our Ad in the April 11 Gazette: Slab-on-Grade Foundations Raise Questions of Durability
Video: Conservation Commission Meeting of 3/12/09; Deadlock on Kohl Condo Proposal
[Below, Paul Wetzel refers to an earlier version of the condo proposal which called for 23 units. The current proposal calls for 20 units.]
3:00:22… Commissioner Paul Wetzel: “…I’m just going to say something, we’ve spent a lot of time listening… right now as this plan…I’m inclined to deny it. And its just because…if we were looking at whether this development has an impact on the wetlands, I think it’s going to have an impact on the wetlands. And, I see, a number of things, primarily the underground [detention basin] getting in the way of the hydrology connections underground…”