NJDOT's Proposed Millstone Bypass:

Assessment of Environmental Disturbance

West Windsor Township and Princeton Township
Mercer County, New Jersey

Prepared by:

Adam G. Stern, Professional Engineer (NJ)
Nicholas W. Agnoli, E.I. (DE)

Prepared for:

Mary Penney, Chair
Sierra Club
New Jersey Chapter
Central New Jersey Group
57 Mountain Avenue
Princeton, NJ 08540-2611

In cooperation with:

The Stonybrook Millstone Watershed Association

December 1999

Introduction

The Millstone Bypass, as proposed, is a 2.5-mile long, federally funded, two-lane highway. It would connect Route 571 (Washington Road east of Route 1) in West Windsor from the NJ Transit / Amtrak station (known as Princeton Junction) over Route 1 just south of the current Harrison Street interchange via an overpass (grade-separated interchange) to Washington Road west of Route 1. The western alignment roughly parallels the Delaware and Raritan Canal (and the Delaware and Raritan Canal State Park, a 70-mile long part of the National Recreational Trail System).

The Bypass would remove three lights from Route 1, (a) the Washington Road/Route 1 junction would permit only right-turns, (b) Fisher Place would become a cul-de-sac and (c) Harrison Street would utilize the overpass and, as determined by NJDOT, potentially reduce congestion in Penns Neck (the community along Washington Road east of Route 1).

According to Sensible Transportation Options Partnership, S.T.O.P., this project may be part of a larger plan, when linked to the Hightstown Bypass and an improved Washington Road (east of New Jersey Transit's Princeton Junction). For those not familiar with the area, this would link the Turnpike to Route 1 (much like the proposed Route 92 farther north).

Well known to locals and alumni for its American Elms (a variety of elm known, understandably, as Princeton) planted in 1920, Washington Road is unmatched as a scenic entrance to one of the nations most academically respected institutions. The Washington Road Elms represent more than aesthetic importance and thus a greater loss if disturbed by the Bypass. The elms are under study by the USDA as they are resistant to the infamous Dutch Elm Disease which has, according to Washington State University's Cooperative Extension website, killed over 75% of the northeast's elm trees since it was accidentally introduced in 1930.Not only will the historic entrance be impacted, however, it would also be circumvented. The Bypass as explained and shown above, will move traffic off of the historic entrance and take cars on a parabolic path over Route 1, stretching much farther north. Washington Road, once the proud gateway to a university older than the United States, will become an under-utilized "right-turn only" feeder road to Walmart', CompUSA' and Home Depot'.

The Sierra Club asks that the NJDOT and FHWA (Federal Highway Authority) consider alternative alignments in light of the potential for impacts to the natural, historical, and cultural resources in the area.

Alternatives to the "final" alignment have been developed by S.T.O.P. and deserve an evaluation. Please see their website at for complete details.

Scope

This report, made possible in part by the Stonybrook Millstone Watershed Association, is designed to summarize a thorough hydrologic analysis of areas potentially impacted by the current Millstone Bypass alignment (as shown in the June 1999 Frederick R. Harris construction drawing on Page 2). Concerns investigated include:

Groundwater recharge.

Stormwater runoff and resulting "non-point source" pollution (a.k.a. polluted runoff).

Loss of agricultural land, wetlands, forest land (dense canopy), landscaped property (grass) and residential property.

This draft report is not an environmental assessment (EA) as defined by the National Environmental Policy Act (40 CFR 1508.9) and should not be construed as such. This document is meant solely to provide a point of comparison to the forthcoming EA from the NJDOT.

Methodology

This work, in its entirety, was performed under the supervision of a Professional Engineer (P.E.) licensed in the State of New Jersey. All areas of impact and their characteristics were determined utilizing a June 1999 construction map drafted by Frederick R. Harris, Inc., 1995 NJDEP aerial photoquads (color, 1 meter resolution), October-December site inspections, Mercer County (ADAM), the NJDEP wetlands delineation theme (GIS), the NJDEP 1986 land use theme (GIS) ­ verified in field, NJ Geological Survey GSR-32: A Method for Evaluating Groundwater Recharge Areas in New Jersey and USDA SCS TR-55: Urban Hydrology for Small Watersheds (1986).

All right-of-way (ROW) areas were assumed to be permanently modified during the construction of the Millstone Bypass. Impervious area was increased solely by the roadway surface and associated paved shoulders. Each lane (of the proposed two-lane roadway) was assumed to be 98% impervious (TR-55, 1986) and 12 feet in width (Harris, 1999). The shoulders were 8 feet in width, paved, and 98% impervious. The constructed runoff channels on either side of the paved roadway surface were 18 and 20.5 feet in width (39, 61, 74 or 80 % impervious depending on soil type). A grassed area separates the channel and the impervious roadway surface and is 10 feet in width on either side of the highway. Its runoff curve number (CN) was assumed to be equal to that of the channel. One-lane on/off ramps were reduced in cross-section by 12 feet.

All commercial and residential land was visually inspected to determine the percentage of impervious area and actual uses (as the land use maps are 13 years old). All discrepancies between the collected data sets were clarified in the field.

All measurements were conservative and accurate to the maximum extent allowed by the data and the respective calculation procedures.

Findings

As forests, wetlands, croplands, open fields, and landscaped areas are replaced by impermeable pavement, the hydrologic cycle is modified. Land that once retained, slowly purified and finally discharged rainwater runoff to local waterbodies and precious groundwater aquifers now, in its impervious state, quickly discharges runoff to surface water. This reduced time of concentration and magnification of peak flow rates allows the bypass of a natural filter and flood mitigation system. Furthermore, the new impervious surface, in the form of a roadway, rapidly discharges stormwater that is often laden with heavy metals and hydrocarbons (petroleum). Not only are average urban pollutant levels increased, the "first-flush" concentration often spikes to many times the ambient level.

The first table of data presented on the following page compares pre-development aquifer recharge with post-development recharge. The difference between the final values (a twenty-five (24.8) percent decrease) is the result of the permanent disturbance to the landscape within the proposed alignment. Groundwater recharge is generally considered to be equal to the total precipitation (I) less the runoff (R), Evaporation (E) and transpiration (T). For the purposes of this mass balance, recharge has been calculated using GSR-32, A Method for Evaluating Groundwater Recharge Areas in New Jersey.

The generated data is used to examine the total acreage of each land cover impacted by the project. Please note that a distinction was made in the "forest" category. "Forest" refers to relatively mature dense woodlands while "treed" refers to sparse woodlands.

Figure 2: Aquifer Recharge

Description	Value (Million Gallons/Year)	Percent Change
Pre-Development	17.77
Post-Development	13.36	-24.8

 

Figure 3: Impacted Land

Description	Stern & Agnoli (Acres)	NJDOT (Acres)	Percent Change
Agricultural	14.71	N/A
Wetlands	1.35	1.02	- 24.4
Forest/Treed	12.28 (combined)	12.75 (combined)	- 3.8
Commercial	4.72	N/A
Residential (Single)	1.07	N/A
Landscaped	21.78	N/A
Impervious	0.60	N/A
Total	56.51	73.79	+ 30.6

 

Figure 4: Yearly Runoff

Description	Value ( Million Gallons/Year)	Percent Change
Pre-Development	35.21
Post-Development (Year 1)	59.79	+69.8
Post-Development (Permanent)	45.04	+27.9

Impervious surfaces, and more specifically highways, impact receiving waters by increasing the peak magnitude and total volume of stormwater runoff, degrading water quality with both chemical and thermal pollution, and permanently modifying aquatic habitat (Horner et al., 1985). Common sources of stormwater runoff contamination include vehicular as well as atmospheric deposition, pavement wear, fertilizers, herbicides, deicing and roadway maintenance. Specific pollutants, and their origins are listed below in Figure 5.

Figure 5: Sources of Pollution in Highway Runoff (US EPA, 1995)

Category	Pollutant	Source
Sedimentation	Particulates	Pavement wear, vehicles, the atmosphere and maintenance activities
Nutrients	Nitrogen Phosphorus	Atmosphere and fertilizer application
Heavy Metals	Lead	Tire wear
	Zinc	Tire wear, motor oil and grease
	Iron	Auto body rust, steel highway structures such as bridges and guardrails, and moving engine parts
	Copper	Metal plating, bearing and brushing wear, moving engine parts, brake lining wear, fungicides & insecticides
	Cadmium	Tire wear and insecticide application
	Chromium	Metal plating, moving engine parts and brake lining wear
	Nickel	Diesel fuel and gasoline, lubricating oil, metal plating, bushing wear, brake lining wear and asphalt paving
	Manganese	Moving engine parts
	Cyanide	Anti-caking compounds used to keep deicing salt granular
	Sodium, calcium and chloride	Deicing salts
	Sulphates	Roadway beds, fuel and deicing salts
Hydrocarbons	Petroleum	Spills, leaks, antifreeze and hydraulic fluids and asphalt surface leachate

 

Past research has demonstrated that as contaminants accumulate in river and stream sediments, habitats may become toxic to freshwater organisms (Boxall et al., 1995).

Based on an average annual rainfall of 44 inches (National Weather Service) in central New Jersey, and a total of 21.3 new acres of impervious area (paved area), the total magnitude of runoff from the Bypass, excluding the 34.56 acres of grassed shoulder, will be 3,405,100 cubic feet per year, 96,252,100 liters per year or 25,427,200 gallons per year (3.67 feet of rainfall * 927,832 square feet of impervious area). Research by Yousef and others in Florida on a similar roadway (connector road with commuter and truck traffic) indicated the pollutant levels shown below in Figure 6.

Figure 6: Average Concentrations in Highway Runoff (Yousef et al., 1985)

Pollutant	Concentration (mg/l)
Zinc	225
Lead	417
Copper	44
Iron	830
Cromium	6.2
Cadmium	1.4
Nickel	21
Ortho-Phosphate	136
Total Phosphorus	280

 

For comparative purposes, pollutant levels permitted within the Millstone River as per the Surface Water Quality Standards, N.J.A.C. 7:9B, are listed below. The Millstone River, as characterized in 7:9B-1.15 as FW2-NT, is a non-trout producing waterway designated for "the maintenance, migration and propagation of the natural and established biota, primary and secondary recreation, industrial and agricultural water supply, public potable water supply and other reasonable uses." Also included in the figure below are the National Drinking Water Standards.

Figure 7: Concentration Comparison

Pollutant	Concentration* (mg/l)	SWQS (N.J.A.C. 7:9B) (mg/l)	National Drinking Water Standards (mg/l)
Zinc	225	No standard	No standard
Lead	417	5	approx. 0
Copper	44	No standard	No standard
Iron	830	No standard	No standard
Cromium	6.2	160	100
Cadmium	1.4	10	5
Nickel	21	516	No standard
Ortho-Phosphate	136	No standard	No standard
Total Phosphorus	280	50	No standard

* based on (Yousef et al., 1985)

 

Figure 8: Total Additional Yearly Loading from the Study Area

Pollutant	Theoretical Pounds Per Year
Zinc	47.9
Lead	88.7
Copper	9.4
Iron	176.6
Cromium	1.3
Cadmium	0.3
Nickel	4.5
Ortho-Phosphate	28.9
Total Phosphorus	59.6

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