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Drainage Analysis-Newgate/Phelps & Hatchett Hill Road Areas Rev. 1 Introduction
3.0 INTRODUCTION
Based on the comments received from residents and town officials through various forums,
CL&P initiated a review of existing drainage conditions in two areas along the GSRP route.
These areas are located in the vicinity of Newgate Road and Phelps Road in East Granby and
Suffield; and Hatchett Hill Road in East Granby. As stated above, the residents are concerned
that construction, including the additional tree clearing proposed by the Project, will
alter/increase the amount and frequency of runoff they currently experience on their property.
The objective of the review was to evaluate existing drainage conditions/patterns and to develop
a plan to manage surface water flow during construction to minimize the chance that the Project
would have a detrimental impact on the existing drainage conditions/patterns. Developing
permanent solutions to the pre-existing surface water runoff or ground water issues (which can
be attributed to development upslope of the right-of-way, conditions created during site work
associated with construction on the parcels where issues now occur, or the construction of homes
on poorly drained soils) are very complex by nature, and are further complicated by the fact that
CL&P’s only interest in the land is by way of easement (limited ownership in fee). As a result,
this plan predominantly focuses on the use of temporary surface water control measures during
construction.
The Project does not propose an increase of impervious surfaces within these areas, therefore it is
not expected that there will be a long-term increase in surface water runoff resulting from the
construction of the Project. Accordingly, the control measures recommended in this report have
been designed to provide adequate control of the existing surface water flow (sheet and
concentrated), and a small, temporary increase in surface water flow that can be expected during
construction. Properly managing the surface water flow will minimize the probability that the
pre-existing localized flooding issues will be exacerbated, and that erosion and sedimentation
issues associated with the ground disturbing construction activities will occur. All the proposed
controls will remain in place until the areas have been stabilized and surface water volumes have
returned to pre-construction levels.
Typically, utility projects such as this are required by the regulating agencies to develop surface
water control measures to protect water resources during construction. However, after being
Northeast Utilities 3-1 Burns & McDonnell
Drainage Analysis-Newgate/Phelps & Hatchett Hill Road Areas Rev. 1 Introduction
made aware of the pre-existing drainage/surface water runoff problems in these areas, CL&P has
developed control measures that normally would not be prescribed if protection of water
resources was the only objective. In the two areas of concern, the traditional control measures
associated with the protection of wetlands and watercourses, minimizing sedimentation and
erosion, and maintaining the stability of all improved surfaces (access roads and crane pads),
have been further augmented by additional control measures to address local concerns. The final
D&M Plan, as submitted to the CSC and each town, has been amended to include all additional
controls identified in this report.
All control measures will be inspected regularly and will be repaired, reinforced, and upgraded
as needed throughout the Project’s duration. Northeast Utilities Transmission Business Unit’s
Best Management Practices: Construction and Maintenance Environmental Requirements –
Connecticut (provided under separate cover or as an appendix to the D&M Plan for Construction
of the Greater Springfield Reliability Project) will be adhered to when inspecting and
maintaining all erosion control measures.
3.1 NEWGATE/PHELPS ROAD AREA, EAST GRANBY AND SUFFIELD The Newgate/Phelps Road area is generally bounded by Phelps Road on the north, Newgate
Road on the west, the western slope of West Suffield Mountain on the east, and the intersection
of Copper Hill Road and Newgate Road on the south. Except for residential development to the
west of the ROW, and scattered residential development to the east, the area consists of wooded
land with varying slopes that are in excess of 30 percent in some areas. This area is shown on
Figure 1.
3.1.1 Public Comments Comments from several home owners along Phelps Road and Newgate Road were received.
Most comments reflected that some residents in this area have installed engineered drainage
systems to control the water that flows down the hill, through the ROW, before reaching their
properties at the base of the slope. These systems are currently effective, but the residents are
concerned the construction may result in runoff changes that their engineered systems are not
designed to handle.
Northeast Utilities 3-2 Burns & McDonnell
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Source: AECOM, Coler & Colantonio, ESRI and Burns & McDonnell Engineering. Image Source: Optimal Geomatics and CT DOT
1,500 0 1,500750 Feet
Legend
Proposed Structures
Existing Structures
Proposed 345kV Route Centerline
Existing Centerline
Parcel Boundary
Existing ROW
Expanded ROW
Wetlands
NU Owned Property
Vernal Pool
Contours (5 ft)
Town Boundary
Drainage Analysis-Newgate/Phelps & Hatchett Hill Road Areas Rev. 1 Introduction
Another resident expressed concern about an existing drainage issue between his home and his
neighbor’s home. According to this resident, during rain events water flows from the ROW
behind their homes to Newgate Road where it frequently freezes during the winter.
3.2 HATCHETT HILL ROAD AREA, EAST GRANBY This area is approximately bounded by Holcomb Road on the north, the western slope of
Hatchett Hill on the east, Hatchett Hill Road on the south, and the approximate toe of the slope
for Hatchett Hill on the west. Adams Road, a cul-de-sac, ends at the west edge of the ROW.
Marsh Pond and its associated wetland system are located to the south of Adams Road. This
system receives surface and ground water from the south, from residential development to the
west and north, and from Hatchett Hill to the east. The west slope of Hatchett Hill is heavily
wooded with steep slopes of 10 percent or greater. This area is shown on Figure 2.
3.2.1 Public Comments A resident that lives at the end of Adams Road expressed concern that Marsh Pond and its
associated forested wetland system south of his property frequently overflows. He further
contends that if the Project causes more water to drain into the pond during construction, it may
exacerbate the problem. The resident states his yard, as well as his street, can be a sheet of ice
during the winter. He suggested that the Project consider tying into the Town’s existing storm
drainage system in the street to capture the runoff leaving the ROW, thereby decreasing the
amount of additional water that ultimately reaches his property.
Northeast Utilities 3-3 Burns & McDonnell
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Legend
Proposed Structures Wetlands Hatchett Hill Existing Structures
Proposed 345kV Route Centerline
Existing Centerline
NU Owned Property
Vernal Pool
Contours (5 ft) NORTH
Locus Map Figure 2
Parcel Boundary Town Boundary
Existing ROW
Expanded ROW 500 250 0 500 Feet Source: AECOM, Coler & Colantonio, ESRI and Burns & McDonnell Engineering. Image Source: Optimal Geomatics and CT DOT
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