STORM DRAINAGE AND FLOOD CONTROL PLAN
T !
COUNTY new jersey
The preparation of this report was financialfy aided through a Federal grout from me Urban Renewal Adminiitration of the Department of Housing and Urban Development 'mder the Urban Planning Assistance Program authorized by section 701 of the Housing Act of 1954, as amended.
The remainder has been financed by local funds and by an appropriation of the state of New Jersey as port of the Cooperative Governmental Planning Program.
Prepared by : ELSON T. KILLAM ASSOCIATES, INC.
APRIL UNION COUNTY 1971 PLANNING BOARD ELSON T. KILLAM ASSOCIATES, INC.
VIII. CHRONICALLY FLOODED AREAS Exhibit XV shows the locations of reported areas of frequent flood
ing within Union County. Two basic distinctions have been made tidal
flooding and flooding from storm water runoff. The areas of tidal
flooding shown on Exhibit XV will generally occur during a fifty-year
frequency tide with tidal elevation of +10' and with no storm water
runoff. The total area inundated under such conditions has been
estimated to be approximately 4,800 acres or 7.3 percent of the total
land area of the County! The method of reducing this extensive
area of flooding is discussed in Chapter IX of this report.
Other areas of frequent flooding shown on Exhibit XV occur from
storm water runoff during periods of heavy rainfall. Questionnaires
were sent to each municipality in the County requesting data on the
location and description of areas of frequent flooding. It was re
quested that areas of flooding be predicated upon occurring on the
average of at least once every five years, cause extensive property
damage, endanger human lives, or halt travel on arterial streets.
A form was prepared and submitted to each municipality to provide
answers to the following questions:'
1. What locations are frequently flooded?
2. What is the frequency of flooding?
3. What is the depth of flooding in streets?
4. What is the cause of flooding?
5. Are improvements planned and, if so, when?
6. Is the flooding beyond the control of your municipality?
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The locations reported have been plotted on Exhibit XV and have
been divided into three classifications. The first, stream flooding
denotes areas where extensive flooding occurs as a result of a major
water course overflowing its bank. The causes of flooding of this
variety are generally insufficient stream channel capacity, insuffi
cient bridge capacity, encroachment into the flood plain or the in
adequacy of a major conduit. The second classification, severe local
flooding, has been used to describe areas where a limited area is
flooded but flooding is frequent, property damage is high, human
lives are endangered, or traffic is halted on arterial streets.
Local flooding has been placed in this classification, particularly
where the flooding occurs on State or County roads or the flooding
in one municipality may result from inadequate facilities in another
municipality. The causes of this type of flooding are generally a
stream channel restriction, an inadequate bridge or culvert, or a
grossly inadequate local collection system. The third classification,
minor local flooding, has been used to show those areas where flooding
was reported to occur but does not create the condition specified
under severe local flooding and is generally within the control of a
single municipality. In this report, emphasis has been placed upon
tidal flooding, stream flooding and severe local flooding. IX. TIDAL FLOODING PROGRAM
Tidal flooding in the eastern area of Union County is a relatively
frequent occurrence. Exhibit XVI, Flood Tide Frequencies, shows that
the yearly high tide is at elevation +5.8'. The fifty-year frequency
tide reaches elevation +10.0'. (All elevations are in feet above mean sea level as measured at Sandy Hook, New Jersey.)
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KILL.N.
h- LiJiu u. ELEVATIONS IN FEET ABOVE MEAN SEA LEVEL AT O SANDY HOOK, NEW JERSEY
SOURCE; u.s. ARMY CORPS OF ENGINEERS
ELSON T. KJI.LAM ASSOCIATES, INC ffyJr&mlic and Samt&ry Engineers
48 ESSEX STREET, MtLLBURN. NEW JERSEY O7O.4!
10 20 30 40 50 60 80 iOC 1 X\/ HI J 1B!I $*% 1 "T"T ELSON T. KILLAM ASSOCIATES, INC.
The discussion of the tidal area adjacent to the Arthur Kill will
be made in two sections. The first section will deal with the area
east of the New Jersey Turnpike and the second, the area west of the
Turnpike.
An area of approximately 2,800 acres east of the New Jersey Turn
pike is below elevation 10.0'. With the exception of the Elizabethport
area, the land use is generally heavy industrial, petrochemical, or
vacant tidal marsh. In some locations, buildings and bulkheads have
been constructed directly adjacent to the Arthur Kill. In other loca
tions, tidal marshes border the Arthur Kill. The industrial residents
of this area have constructed their facilities with full awareness of
the inevitability of periodic flooding during periods of extremely
high tides.
Protection of the entire area land east of the Turnpike against
periodic tidal flooding, even if desired, would not be economically
feasible. The soil conditions adjacent to the Arthur Kill and the
extremely long dike that would be required to prevent flooding are
the controlling factors.
However, local areas east of the Turnpike may be protected by either placing fill to the desired elevation or by the construction of
limited dikes and local pumping facilities. There are approximately 2,000 acres west of the New Jersey Turn
pike which are below elevation +10.0' which are susceptible to periodic flooding from high tides. However, the construction of the
Turnpike to elevation +12 has isolated this area from the Arthur Kill,
with the exception of only nine locations. These are the bridges and
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culverts for the major streams listed below:
1. Rahway River, Linden
2. Marshes Creek, Linden
3. Piles Creek, Linden
4. Morses Creek, Linden
5. A Culvert at Standard Oil, Linden
6. A Culvert Near Alien Street, Linden
7. Elizabeth River, Elizabeth
8. Great Ditch, Elizabeth
9. Bound Creek, Elizabeth All tidal flooding which inundates areas west of the Turnpike enters
through these nine culvert locations.
Where the area east of the Turnpike is primarily susceptible directly
to tidal flooding, the low areas immediately west of the Turnpike are
generally susceptible to both tidal flooding and storm runoff. For
this reason, simply closing off these nine openings during periods of
flood tide is not a solution. There are two means of solving
this problem of extensive flooding west of the Turnpike during high
tides. The first is to provide tide gates and a pump station at the
Turnpike crossings to prevent tide water enty and to discharge the flow
of the stream into the Arthur Kill during high tides. This type of
installation was proposed for the area tributary to Bound Creek, known as Newark Meadows project, to protect the low-lying areas
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in the City of Newark and Frelinghuysen areas from frequent flooding
during high tides and heavy rainfalls. This is a proposed City of
Newark Project which would also benefit tributary areas of the City
of Elizabeth.
The second approach to limiting the tidal flooding of low lying
areas is to construct dikes and levees along the river banks and to
provide pump stations to eject the local runoff into the River.
This approach has been recommended by the United States Army Corps of Engineers for the Elizabeth River and has been undertaken,
in part, in the City of Rahway.
For more detailed discussion, the area west of the New Jersey Turn
pike has been divided into the four natural drainage basins:
1. Newark Airport, Bound Creek
2. Elizabeth River 3. Morses Creek
4. Rahway River
1. Basin 1, Newark Airport is defined as that area north of
Livingston Street in Elizabethport.
A substantial area of the City of Newark, Newark Airport and a
large area of Elizabeth are drained by a peripheral ditch which skirts
the west, south and southeastern boundaries of Newark Airport. This
main interceptor ditch has recently been constructed by the Port
Authority and provides a very satisfactory open channel outlet for
storm water runoff during periods of low tides. However, during high
tides, no outlet is provided for storm water runoff as the existing
tide gates at the Turnpike culvert are then closed by tidal action.
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As a result, the storm water runoff in the peripheral ditch backs up,
creating surcharge, and flooding in low-lying areas, and extensive
damage and interruption to traffic results. To relieve this condition,
the construction of a storm water pumping station was proposed in
1961. The Port Authority offered to contribute toward the cost of
construction which would be undertaken by the City of Newark, the pri
mary beneficiary of the proposed improvement. The report recommended
that the area of Elizabeth, generally north of North Avenue and west
of Division Street, also be serviced by the proposed pumping station.
Since the report was prepared, the peripheral ditch has been constructed
immediately north of North Avenue. The area immediately south of North
Avenue, which is tributary to Great Ditch, is also susceptible to flood
ing and is isolated from the Arthur Kill with the exception of a
single culvert under the Turnpike.
The tributary area to the Great Ditch at the Turnpike culvert is
approximately one square mile. It has been planned to divert the
western third of this drainage area, above Division Street, into the peripheral ditch. The southern portion will remain tributary to the
Arthur Kill through the Great Ditch. The estimated cost of the proposed
Newark Meadows Storm Water Pumping Station, if constructed in 1961,
was $1,300,000. Updated to present day costs,the cost would be about
$2,800,000. In the future, it may also be found desirable to protect
the area of the Great Ditch west of the Turnpike from tidal inundation.
At such time the connection of the Great Ditch into the Peripheral
Ditch system rather than the construction of separate pumping facilities
should be considered.
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2. Elizabeth River
The U. S. Army Corps of Engineers has prepared preliminary plans
for the improvement of the Elizabeth River, the second drainage
basin. The project is designed to provide protection against both
high tides and peak storm runoff. As shown on Exhibit XVII this im
provement calls for a system of levees, flood walls and flumes. The
levees will begin at South First Street and will extend upstream to
Spring Street. Flood walls will be constructed from Spring Street to
near Bridge Street where the flume section will begin. The tidal in
fluence extends upstream to South Broad Street. Above this point,
flood damage is due primarily to storm water runoff rather than tidal
inundation.
The construction of the recommended facilities will prevent the
flooding of 300 acres of land adjacent to the Elizabeth River between
South First Street and South Broad Street. The cost of this project
was estimated to be $10,075,000 in 1964 by the Army Corps of Engineers.
It has more recently been estimated to cost $20,000,000, based on
present day prices. This project is expected to be under construction
in the near future. The Union County Engineering Department is planning to replace three bridges in 1971 across the Elizabeth River that have
been determined to be inadequate. These bridges are located on
Summer Street, South Street and Bridge Street. The construction of the proposed Corps of Engineers Elizabeth
River Improvements should receive a high priority on the list of
required Countywide Storm Drainage projects.
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3. Morses Creek
The third drainage basin east of the Turnpike which was studied is
Morses Creek, which is located in Linden. An area of approximately
535 acres falls below elevation +10.0 in this drainage basin. The
area extends from Alien Street on the north to Wood Avenue on the
south. The majority of the area is heavily industrial with emphasis
on the Petrochemical Industries.
In this area, there are four major culverts where tidal waters can
cross beneath the New Jersey Turnpike. These include the culvert near
Alien Street, a channel at Standard Oil, Morses Creek and Piles Creek.
All four of these water courses could have tide gates installed at
the turnpike and could be interconnected by open channels west of the
Turnpike. If this were done, a single storm water pumping station
could be installed to serve the combined drainage areas. This would
result in the most economical means of providing protection from tidal
flooding. Tide gates would be required at the four locations and a
pumping station of approximately 1,500 to 2,000 cfs capacity would be
required to pump storm water flows. A cost estimate has been made for
the undertaking of these improvements and is shown in Table IX.
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TABLE IX
COST ESTIMATE
Morses Creek Area Tidal Flooding Prevention Program_____
Pump Station (1,500 - 2,000 cfs) $2,500,000 Four Flood Gates 400,000 Channel Excavation 350,000 Bridges and Culverts 250.000
Estimated Project Construction Cost ------$3,500,000 Contingency and Engineering ------900,000
TOTAL PROJECT COST $4,400,000
These proposed facilities would not only eliminate the tidal flooding
which frequently occurs in the low-lying areas but will also eliminate
the frequent surcharging of West Brook, Peach Orchard Brook, and backup
and surcharge of local drainage facilities during high tide levels of
+6.0' or higher.
It is recommended that a detailed survey and study of this proposal
be undertaken to determine whether this project is warranted. If it
can be demonstrated that extensive damage would be prevented and that
sufficient unimproved land would be benefited, the economic feasibility
of constructing these facilities could be demonstrated.
4. Rahway River
Another area west of the Turnpike, that is subject to tidal flooding
is along the Rahway River. The U. S. Army Corps of Engineers has con
structed dikes along a portion of the Rahway River in the City of Rahway.
These dikes are located along the main branch of the river betxvreen
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Lewis Street and Hazlewood Avenue. The diking in this area is intended
to prevent both tidal and storm water runoff flooding. The remainder
of the river is unprotected. The Corps of Engineers has studied the
Rahway River in detail and has determined that the high cost of flood
protection facilities required to prevent flooding are not economically
justified for the remaining contiguous areas adjacent to the river.
In the future, as land values increase and continued marginal
development is permitted, additional facilities may become necessary.
Such improvements would consist of levees and flood walls as have
recently been constructed in the City of Rahway.
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X. STREAM IMPROVEMENT PROGRAM
PASSAIC RIVER The U. S. Army Corps of Engineers has prepared a comprehensive study on the entire Passaic River Basin. A summary of the findings has been presented in a report titled, "Passaic River Basin Water Resources 2 Development Information Bulletin". The major proposals and recommenda tions in this study that will influence Union County are the construction of a proposed flood retention reservoir and conservation dam above Millington and the deepening and widening of the Passaic River Channel downstream of this reservoir. The proposed dam and reservoir at Millington would be designed to reduce the peak storm water flow by retaining the flood waters behind the dam during periods of heavy rainfall. The retained water would then be used during dry weather periods to regulate, augment and generally maintain a minimum flow of not less than 38 million gallons a day immediately downstream of the dam in the Passaic River. This flow augmentation will help maintain a desirable degree of dilution for sewage treatment plant effluents discharged into this branch of the Passaic River. The significance of the low river flow augmentation can be ap preciated more fully when it is realized that during the month of July, 1966, the average flow at the Chatham Gaging Station was 5.0 MGD,
a point where the drainage area is 100 square miles. Nearly one-half
of that flow was estimated to be treated effluent. The proposed river channel from Berkeley Heights to Summit would have an 80-foot base width, a 1 on 3 side slope, which would be earth lined, and the river depth would be increased by about 5 feet. - 56 - ELSON T. KILLAM ASSOCIATES, INC.
The U. S. Corps of Engineers requires that the State, County or
Municipal Governments provide all properties needed and to pay for
the cost of relocating all utilities and bridges required for this im
provement. The Union County Park Commission has acquired a great deal
of the property along the river and has been authorized to acquire much
of the remaining privately owned land. The land acquired along the
river by the Park Commission on behalf of the County will serve the
following purposes:
1. Provides open space areas for general recreation.
2. Will serve as a flood plain to accommodate severe flood flows.
3. Eliminates the possibility of additional flood plain encroachment
and the resultant flood drainage to improved property
4. Land required to permit construction of the proposed Corps of
Engineers project is being made available at least cost with
maximum benefits.
Much of the land adjacent the Passaic River is quite low and has not
been developed because of the frequent flooding and local restrictions
on construction. It has been reported that the proposed channel im
provement by the proposed Corps project will enhance 315 acres of land
located in Union County. A great deal of this property is presently
park land, and this land could be developed for a variety of recreational purposes.
One of the greatest expenditures of funds required of Union County
will be to provide the necessary modifications or reconstruction of
the existing bridges over the Passaic River. All of these bridges - 57 - ELSON T. KILLAM ASSOCIATES, INC.
are Bi-county bridges, serving Union and Morris Counties, thus a sharing
of the costs of the improvements would be anticipated.
TABLE X
PASSAIC RIVER BRIDGES REQUIRING REPLACEMENT
Vehicular Bridges to be Raised Required Min. Low Steel Elevation
Summit - Millburn Route 24 (Under Construction) 193.0 Summit Chatham Road 193.0 Summit River Road 193.0
Bridges to be Removed
Summit Stanley Avenue
Vehicular Bridge Spans to be Increased
Summit Mt. Vernon Avenue 217.0 New Providence Passaic Street 208.0 New Providence Central Avenue 210.0 Berkeley Heights Snyder Avenue 209.1 Berkeley Heights Springfield Avenue 214.0
Railroad Bridge Spans to be Increased Summit Erie-Lackawanna Berkeley Heights Erie-Lackawanna
A preliminary cost estimate has been prepared for the replacement
of the bridges shown on Table X, except for the Rt. 24 bridge which is
presently under construction. It has been assumed that all participating
agencies would share in the costs of the Railroad Bridges as well as the
vehicular bridges as the financial status of the railroad may prevent
their sharing in these costs at this time.
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The estimated cost distribution follows:
N. J. State Department of Transporation - 50% = $1,800,000
Morris County - 25% = 900,000
Union County - 25% = 900.000
TOTAL $3,600,000
The undertaking of this work would have to conform to the requirements
of the Corps of Engineers schedule for river improvements.
BERKELEY HEIGHTS
The land area of Berkeley Heights drains into two major watersheds,
the Passaic River and Green Brook, a tributary of the Raritan River.
The majority of the area West of the ridge line drains to the Passaic
River through four streams, the largest of which is approximately 0.9
square miles in area. The upper reach of each of these tributary streams
is extremely steep, being 10 percent or greater. The steep slopes in
the upper reaches result in short times of concentration and high rates
of runoff. The lower reach of each of these streams is relatively flat
with some sections within the Passaic River flood plain.
A comprehensive Storm Drainage Plan is presently being prepared for
Berkeley Heights by Elson T. Killam Associates, Inc. Every major water
course within the Township, with the exception of the Passaic River and
Blue Brook is being studied. The study will result in the preparation
of preliminary plans to cover a long range plan of improvement for
critical reaches along the streams.
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The locations where frequent flooding has occurred are shown on
Exhibit XV. These areas are being given special attention and the
construction of drainage facilities at five problem areas has already
been undertaken under the proposed Township comprehensive plan for
storm drainage improvements. Most of the stream improvements in
Berkeley Heights will be required where the tributary area is less than
one-half square mile, the minimum drainage area considered in this
report. For this reason, and because the Township plans are not
finalized, only a general description of the proposed stream improve
ments will be made, and a determination of the adequacy of the County
bridges and culverts will be limited to the points of analysis shown
on Exhibit VIII.
In the steeper areas where velocities are extremely high, the
general plan is to prevent further serious erosion and control local
flooding by enclosing or piping the smaller water courses, with concrete
or rip-rap lining provided for the larger water courses. To obtain the
desired degree of protection, the replacement of some County culverts
and bridges may be necessary. The County should schedule the replace
ment of these conduits to coincide with the scheduled local stream improvements.
The lower reaches of the streams tributary to the Passaic River
are influenced by the flood stages in the main river. Even during dry
weather, some of the local streams are surcharged by the high river
levels in the Passaic River. Under backwater conditions such as this, tributary channels become silted quite rapidly and require constant
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maintenance. The U. S. Army Corps of Engineers flood control improve
ment planned for the Passaic River will lower the flood stage levels and
normal water surface levels in the River which should reduce the local
silt problem in tributary streams.
The Union County bridges and culverts located at the points of study
and analysis in Berkeley Heights are generally adequate in size and
carrying capacity. Three exceptions are the bridges at Locations P2,
G4 and G7. The bridge at Location P2, Stream 3-60 at Park Avenue, is
of marginal capacity. A detailed hydraulic analysis of the stream and
the culvert will be required to determine whether this bridge can be
incorporated into an overall stream improvement plan. The bridge at
Location G4, Stream 14-14-11 at Horseshoe Road is also of marginal
capacity and will require a similar analysis.
The only County culvert at a point of analysis found to be inadequate
is the one at Location G7. It is reported that during heavy rainfalls
the water levels at this culvert become so high that a portion of the
stream flows across Valley Road. This creates a hazardous condition on
this heavily traveled County road and the culvert should be considered
for enlargement by the County.
NEW PROVIDENCE
The majority of the land area of the Borough of New Providence is
tributary to the Passaic River through Salt Brook. The Borough of New
Providence has been engaged in a long range plan of improvement of Salt
Brook since 1959. At that time Elson T. Killam Associates, Inc., were
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retained by the Borough to prepare preliminary plans for improvements and
enlargements to Salt Brook and its major tributary streams. As funds
have become available, reaches of the stream have been improved by the
Borough. The work to date has generally been done in the lower reaches
of the main branch and west branch.
The improvements have very significantly reduced the frequency of
flooding in these lower areas, particularly in the business areas and
heavily traveled streets in the Borough. However, some minor local
flooding and high water still occur as the result of backwater from
the Passaic River under flood stages. The elimination of this condition
is beyond the local control of the Borough of New Providence. The
U. S. Army Corps of Engineers proposed project for improvement to the
Passaic River basin will solve this problem. The construction of the
flood detention reservoir near Millington and the improvement of the
River channel from Millington to Millburn will lower the storm water
stages or high water levels in the Passaic River. This will in turn
reduce the frequency of flooding and high water along the lower reaches
of Salt Brook and its tributaries.
Presently, the most frequent and severe flooding in New Providence
occurs along the upper reaches of several branches of Salt Brook. The
cause of the flooding is generally insufficient channel capacity. The
Borough of New Providence has plans to correct these conditions as funds
are made availabe. The planned improvements are shown on Exhibit XVII.
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In addition to the channel work required, two County bridges have
been determined to be insufficient in capacity and will require replace
ment. These bridges are tabulated below:
Analysis Location No. County Bridge No. Street jBtream
P-ll New Providence, 37 South Street Br. Salt Brook, 3-51-2
P-12 New Providence, 7 South Street Salt Brook, 3-51
The construction of these bridges should be scheduled to coincide with
the proposed local channel improvements. The total cost of the stream
improvement program was estimated to be $1,000,000 in June of 1960.
Nearly $400,000 has been spent since 1963 for stream improvement work
by the Borough of New Providence. The 1960 cost estimate for the im
provements not yet made.totals approximately $700,000. At today's prices
the estimated project cost to complete this work may approximate
$1,240,000, a 75% increase in only ten years reflecting the effect of
inflation upon construction costs.
SUMMIT
The City of Summit is located on the ridge line dividing the Passaic
and Rahway River watersheds. The slope of the land is relatively steep
and averages approximately 5%. The City of Summit is principally a
residential community and has only a minimum amount of unimproved land
remaining for development. The flooding problems in the City of Summit
are considered to be probably the least severe of any other municipality
in the County. Flooding occurs at the location shown on Exhibit XV at
least once a year. The flooding indicated at two major locations is - 63 - ELSON T. KILLAM ASSOCIATES, INC.
considered to be generally beyond the control or ability of the City
alone to correct.
Stream 3-44 crosses River Road at Location P-18. It has been
reported that River Road is flooded to the full depth of the curb at
this location about once a year. An analysis of the County Bridge at
this location, Summit, 7, indicates that it has a capacity of only
one-half of the recommended capacity. River Road is a major access
route to the City from the West. It is important that this major artery
be kept open at all times.
The second area which is frequently flooded is located at the
Division Avenue Bridge over Salt Brook, Analysis Location P-7. The
flooding at this location is reported to reach a depth of one foot on
Division Avenue about once a year. A preliminary analysis of this
bridge indicates that it is of marginal capacity when the full flow
area is available. Presently, a substantial amount of silting has
occurred reducing the capacity of the bridge. The channel downstream
of the bridge in New Providence is generally inadequate and plans for
its improvement have been prepared for the Borough of New Providence
by Elson T. Killam Associates, Inc. When funds become available the
Borough proposed to undertake these improvements. It would be of limited
benefit to reconstruct this bridge prior to undertaking the downstream
improvements. If flooding persists after the downstream improvements
have been completed, it is recommended that this bridge be replaced.
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GREEN BROOK IMPROVEMENTS
The head waters of Green Brook are formed in the Watchung Mountains
of Berkeley Heights, New Providence, Summit and Mountainside. The stream
slope is quite steep in the mountainous areas but is quite flat down
stream of Park Avenue in Scotch Plains.
Scotch Plains and Plainfield have experienced extensive and frequent
flooding along Green Brook. In one area of Plainfield, between Farragut
Road and Leland Avenue, the flooding is so severe that the flood waters
from Green Brook, on occasion, flow through a residential area at a depth
of over three feet into Cedar Brook, 2,500 feet to the east. The area
inundated at this location is approximately 150 acres. There are
numerous other locations in these low-lying areas that also experience
severe flooding.
As a first step to eliminate this flooding, the State of New Jersey,
Department of Environmental Protection, Division of Water Resources, has
had a study conducted to define design flood flows and floodways for
Green Brook*. The results of this program have been presented on plans
entitled, "Delineation of Floodway and Flood Hazard Area, Green Brook".
Preliminary copies of these plans are available from the Department of
Environmental Protection, Division of Water Resources.
The preliminary design flows for major reaches of Green Brook
within Union County are presented below:
SCudy by Anderson-Nichols & Company, Boston, Massachusetts
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TABLE XI
DESIGN FLOWS
GREEN BROOK
Floodway Flood Hazard Area Design Flood Design Flood
Plainfield
Jefferson Avenue to Stony Brook 4,080 cfs 5,100 cfs Stony Brook to Sycamore Avenue 2,280 cfs 2,850 cfs Sycamore Avenue to Terrill Road 1,920 cfs 2,400 cfs
Scotch Plains
Terrill Road to Route 22 1,920 cfs 2,400 cfs Route 22 to New Providence Road 1,440 cfs 1,800 cfs
Berkeley Heights
New Providence Road to Plainfield Avenue (at Hampton Drive) 600 cfs 750 cfs
Using these flows, a conceptual type of investigation has been made
to determine the order of magnitude of improvements which might be re
quired for Green Brook to eliminate frequent flooding. Table XII sum
marizes the results of this investigation.
The improvement of the Union County reach of Green Brook should
be done in conjunction with an overall improvement program for the en
tire stream extending to its confluence with the Raritan River. Restric
tions in Green Brook downstream of the Union County section are partially
responsible for the flooding in the Green Brook Park area of Plainfield.
Because of this, widening and realigning of the channel only between
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Jefferson Avenue and West End Avenue will not significantly eliminate
the flooding in this area.
Approximately 60 acres within Union County are flooded between West
End Avenue and Jefferson Avenue at a flood flow of 5,100 cfs in Green
Brook. This corresponds to a storm of approximately 25-year frequency.
There are only three homes within this floodway in Union County. The
remaining area is parkland. However, on the other side of the stream
in North Plainfield, in Somerset County, there is extensive flooding
of residential property under the same flow conditions. The improvement
of this reach of the stream will be warranted primarily to reduce property
damage in North Plainfield.
The water surface elevation in the reach upstream of West End Avenue
is not controlled by downstream conditions. Thus, upstream improvements
will be beneficial.
Some of the most extensive flooding in Scotch Plains and Plainfield
occurs along the reach of Green Brook between West End Avenue, Plainfield
and Union Avenue in Scotch Plains.
Approximately 250 acres of residential, commercial, and industrial
property within Union County are flooded by a 25-year frequency storm.
An equally large area in North Plainfield is also flooded under these
conditions. This flooding results in extensive property damage and
interferes with transporation and vital services such as fire and police
protection. When this extensive an area is flooded, sanitary sewers
generally become surcharged which results in sewage backing up into
basements and flowing out of manholes into the already-flooded streets.
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This creates a hazard to public health and safety. The improvement of
this reach of Green Brook, between West End Avenue and Union Avenue
should be given one of the highest priorities in the County.
The approach taken in the conceptual design was to minimize the cost
of the improvements by using earth channels wherever possible. If there
is not sufficient clearance between building or if steep channel slopes
are required, more costly concrete lined channels will be required.
It has been recommended that several bridges be replaced. This is
necessary because the bridge span is insufficient or the required channel
improvement would undermine the existing bridge footings. In the final
design, a channel profile might be developed which would not require
replacement of all of these bridges. In other locations, it has been
assumed that some existing retaining walls can be retained and incorp
orated in the final channel improvement, thereby reducing the project
cost. The estimated project cost for the reach between West End Avenue
and Union Street, including engineering, legal, construction contingencies,
is approximately $6,350,000.
The improvements upstream of Union Avenue, extending to New Providence
Road, are designed primarily to reduce the vast quantity of debris that
is carried down the steep mountain slopes and then deposited in the
downstream channels. It is recommended that at least the siltation basin
be constructed. The basin will trap the debris and reduce the mainteance
cost in the downstream channels. However, periodic cleaning of the basin
will be required. It is believed that the steep channel between Union
Avenue and New Providence Road contributes a large portion of the debris. - 68 - ELSON T. KILLAM AS SOCI AXES, INC.
If it is found that the siltation basin requires excessive maintenance,
the lining of the channel between Union Avenue and New Providence Road
should reduce this significantly.
This expenditure is beyond the means of the municipalities bordering
Green Brook. Federal, State and County assistance will be required to
implement this project. The U. S. Army Corps of Engineers is presently
preparing a "Survey Report for Flood Control" on Green Brook from
Scotch Plains to its mouth. An evaluation of the cost of this work is
being made for a wide range of flows to determine which flow is most
economically feasible. The minimum flow being investigated is the 1938
flood, which was recorded to be 2890 cfs at Sycamore Avenue. For
comparison, the Flood Hazard Area Design Flow of the Department of Water
Resources at this location is 2400 cfs. The results and recommendations
of the Corps of Engineers study are not expected to be available for
several months.
As an interim measure, for at least some relief from major flooding,
it has been suggested by Mr. James D. Josephs, Plainfield City Engineer,
that flood detention basins be constructed along Green Brook and Blue
Brook in the Watchung Reservation area. Two sites appear to be the
most promising:
1. Seeley's Pond on Blue Brook, immediately above the confluence with Green Brook 2. The undeveloped area immediately above Union Avenue on Green Brook.
Normally, the construction of a detention basin involves the place
ment of an embankment to back water up in an existing depressed area.
The only suitable site of this type on Green Brook is Seeley's Pond, - 69 - ELSON T. KILLAM AS SOCIATES, INC.
located in the Watchung Reservation. The dam has an 80-foot long spillway
which provides a normal water surface elevation of 205.5'. The dam height
is nearly 15 feet, but silt and debris have reduced the normal water deptu
to as little as one foot behind the dam. The replacement of the existing
dam with a higher structure designed for flood control would be extremely
costly. To minimize costs, the study was based on utilizing the existing
dam and installing a new spillway in one of the abutments.
To obtain storage volume, the silt and debris behind the dam must be
removed, and a water surface control spillway must be constructed at a
lower elevation. To preserve the natural beauty of the pond, water must
be maintained at a depth of at least three feet and the lowering of the
normal water surface must be kept to a minimum. For this investigation
the normal water surface was assumed to be lowered 5.5 feet to elevation
200'. This would require the excavation of the silt and debris to eleva
tion 197' to maintain the minimum of three feet of water.
The second site, north of Union Avenue, is presently undeveloped ar.,1
would be located at least in part on privately-owned land. The detention
basin would have to be excavated. The downstream channel invert ele
vation of 152' and the surrounding ground elevation of 161' controls the
available depth in the basin.
Both basin sites will provide only a limited storage volume. Because
of this, the detention basins will effectively reduce peak flows for a
narrow range of flows. In other words, if a design storm of 5-year
frequency is selected, the efficiency in reducing the peak flow of a
25-year storm will be minimal. The following Table illustrates the
- 70 - ELSON T. KILLAM ASSOCIATES, INC.
efficiency of the basins to reduce the flood flows in Green Brook. The
outlet works were sized for maximum reduction of the five-year storm peak
flows. This results in less efficient operation at other flows, as is
illustrated by the reduction of the two-year frequency storm.
TABLE XIII
GREEN BROOK DETENTION BASIN EFFICIENCY
Storm Seeley 's Pond Seeley 's Pond & Union Ave. Percent Frequency Peak Peak Peak Natural Peak Basin Reduction Natural Basin Flow CFS Discharge CFS Flow Discharge CFS CFS
2 273 233 656 552 15.8%
5 374 289 900 740 17 . 8%
25 508 508 1220 1220 0 %
The peak flow of a 25-year frequency storm will not be reduced by the
detention basins. The storage volume of the basins will be filled by
runoff preceeding the peak flow and the peak flow would pass through
the basins with negligible reduction.
The total volume of water detained during a 5-year and 2-year
frequency storm would be 1,900,000 and 947,000 cubic feet,respectively.
Greater efficiency could be obtained for a 2-year storm if it were
selected as the design storm. However, this would result in poor control
or reduction of flow with a 5-year storm.
The following table shows the percentage flow reduction in the
downstream reaches for a 5-year storm. It has been assumed that the
160 cfs peak flow reduction will remain constant.
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TABLE XIV
GREEN BROOK DETENTION BASIN
5-YEAR FREQUENCY PEAK FLOW REDUCTION
Natural Reduced Location Flow CFS Flow CFS Percent
Park Ave. 990 740 82%
Sycamore Ave. 1220 1060 87%
Jefferson Ave. 2340 2180 93%
As is readily apparent, the greatest benefit of the detention basins
will be in Scotch Plains and the northern area of Plainfield. Downstream
of the confluence of the Green Brook and Stony Brook, the effect of the
detention basins will be minimal.
To obtain the storage volume, it has been estimated that 38,000 and
47,000 cubic yards of material will have to be excavated from Seeley's
Pond the Union Avenue site, respectively. The removal of this
material represents the majority of the work required to improve these
sites. The cost of this excavation could be as much as $4.50/cubic
yard, resulting in a cost of about $380,000, if disposal sites are not
available in the immediate area. However, if fill material is required
for another project in the general area or nearby disposal sites are
available, the cost could be as little as $2.00/cubic yard resulting in
a cost of $170,000. The spillways for the basins could be constructed
for a cost of approximately $100,000 to $150,000 which would bring the
total project cost up to $300,000 to $500,000.
- 72 - ELSON T. KIL.LAM ASSOCIATES, INC.
The desirability of the basins can only be established by a detailed
analysis of Green Brook at flow rates corresponding to two and five-year
frequencies in the existing channel. The communities of Scotch Plains,
Plainfield, Watchung and North Plainfield would be the only municipalities
along Green Brook to benefit from detention basins. A detailed analysis
of the stream may reveal that it is more beneficial to spend $300,000
to $500,000 on locitl stream improvements in the reach above Stony Brook
because of the modest reduction obtained from flood flow by the
construction of these basins.
In addition to the extensive flooding along Green Brook, there is
severe flooding in other areas of the watershed. The East Branch of
Green Brook, Stream 14-14-6, is formed in Mountainside and Scotch Plains
and flows southwesterly along Rt. 22 to its confluence with Green Brook
at Union Avenue, Analysis Location G-8. This stream has been under
study for improvement for several years by the Township of Scotch Plains.
In 1963, Elson T. Killam Associates, Inc., prepared a "Preliminary Report
Upon Storm Water Flooding Along the East Branch of Green Brook" for the
Township of Scotch Plains. During storms of less than five-year
frequency, water ponds up to a depth of two feet on Rt. 22.
The major cause of this flooding is the inadequate culverts under
local streets and Rt. 22. Plans have been prepared for improvements
which will greatly reduce the frequency of flooding on this major highway.
A request for aid from the State Department of Transportation has been
made by the Township of Scotch Plains. Construction of this project
will begin when a firm commitment of aid is made by the State. The
- 73 - ELSON T. KILLAM ASSOCIATES, INC.
total cost of this project was estimated to be $668,000 in October, 1963.
Within the City of Plainfield, there are approximately 15 streets
which pass under the Central Railroad of New Jersey. It has been
reported that the underpasses at Rock Avenue, Clinton Avenue, New Street,
Park Avenue, Watchung Avenue and Roosevelt Avenue flood to a depth of
one foot at least once a year. The Central Railroad of New Jersey runs
the length of Plainfield from east to west, generally paralleling Green
Brook, and is elevated with depressed road crossings under the railroad.
With the limited highway access across the railroad, travel becomes
extremely difficult when nearly half of the underpasses become flooded.
This condition is dangerous as it prevents the normal function of fire
and police protection.
All six of the frequently flooded underpasses are served by gravity
storm sewers which are tributary to Green Brook. The flooding is
attributed to a combination of inadequate storm sewers and backup or
surcharge from Green Brook. A detailed analysis of this problem should
be made to determine the causes of the flooding. If it is found that
relief sewers will eliminate the flooding, it is recommended that this
work be undertaken in advance of the Green Brook channel improvements.
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CEDAR BROOK
The headwaters of Cedar Brook are formed in Scotch Plains and Fanwood.
The brook flows southwesterly through Plainfield into Middlesex County.
The tributary area of Branch 14-14-3-4, which originates in Scotch Plains,
is approximately 1.20 square miles at Terrill Road, the Township Boundary.
Only minor flooding has occurred along this branch in Scotch Plains and
major improvements are not felt to be warranted.
However, Branch 14-14-3-4-2 which is formed in Fanwood has flooded
quite frequently. The tributary area is approximately 0.42 square miles
at Terrill Road. This is Location "C2" on Exhibit VIII. A study has
been made of the flooding of the reach of Cedar Brook upstream of this
location by Richard 0. Luster, Borough Engineer of Fanwood.
One of the major recommendations of the study was the relocation of
several sanitary sewers and other utilities which pass through bridges
and culverts. The sanitary sewers are greatly restricting storm water
flow at Terrill Road, Russell Road, Willoughby Road. The construction
of the East End relief sewer by the City of Plainfield in 1968 has pro
vided a new outlet at the lower elevation for the Fanwood sanitary sewers.
As proposed by Richard 0. Luster, a substantial increase in storm sewer
capacity can be obtained at a relatively minor cost by relocating these
local Borough sanitary sewers. The project cost was estimated to be
$75,607 in December of 1968.
It is recommended that the relocation of these sanitary sewers be
accomplished as a first stage of the Fanwood-Cedar Brook storm drainage
improvement. The second stage development would consist of the con
struction of a retention basin as outlined by the previously mentioned
study or by the construction of relief storm sewers.
- 75 - ELSON T. KILLAM AS SOCIATES, INC.
Because of the controversy concerning this proposed improvement, the
Borough of Fanwood engaged another consultant to review the proposed
recommendation. The study generally recommended the construction of the
detention basin to reduce flooding.
The two main branches of Cedar Brook join immediately south of the
Terrill Road and East Third Street intersection in Plainfield. The
brook is conducted from this point to Cedar Brook Park, a distance of
12,800 feet, in a box culvert. The culvert was constructed in 1923
as the first of a two-stage development. The second stage was deferred
and was planned to be constructed when required and was to consist of a
parallel conduit of the same size as the original. Thus, in 1923 it
was realized that eventually at least a doubling of the conduit capacity
would be required as the tributary areas developed and paved areas re
sulted in increased runoff, and for this reason the additional width of
rights-of-way was obtained and, where practical, other utilities have
been located to allow for the future construction of the parallel conduit.
A preliminary analysis of the Cedar Brook box culvert indicates that some
reaches are capable of carrying only one-half of the recommended design
flow. This is in agreement with the design flows determined in 1923
by Weston E. Fuller Associates, the designers of the original culvert.
The addition of a second conduit with an area ranging from 50 sq. ft.
to 70 sq. ft. would be required to pass the recommended design flow.
A preliminary estimate indicates that the cost of the box culvert of
approximately 12,800 feet would be approximately $5,000,000.
In the northeast area of Plainfield, Cedar Brook flows parallel to
and only 2,000 to 3,000 feet southeast of Green Brook. The topography
- 76 - ELSON T. KILLAM AS SOCIATES, INC.
is so flat between the water courses that under extreme flood flow conditions
(15-year frequency) Green Brook water flows through City streets into Cedar
Brook. At Terrill Road, the invert elevations of Green Brook and Cedar
Brook are 126.0 and 118.6, respectively. At Netherwood Avenue, the invert
elevations of Green Brook and Cedar Brook are 114.0 and 106.5, respectively.
The tributary area of Green Brook at Terrill Road is approximately 8.5
square miles, while that of Cedar Brook is only 1.6 square miles.
To eliminate the need for the construction of the second Cedar Brook
conduit, an investigation was made of the feasibility of diverting a
portion of the Cedar Brook flow into Green Brook in the general area of
Terrill Road.
The increase in flow in Green Brook, a maximum of about 20%, could be
carried in an improved Green Brook channel at a fraction of the cost of
constructing the second barrel of the Cedar Brook culvert.
However, the diversion is impractical because the stream elevations
at Cedar Brook are approximately 7 feet below Green Brook in the Terrill
Road and Netherwood Avenue area.
Flooding along the reach of Cedar Brook in Plainfield has generally
been limited to the northern and southern extremes. The flooding in
the Terrill Road area of both Fanwood and Plainfield acts as a natural
detention basin, generally reducing the flooding in the central portion
of Plainfield.
Approximately 25 acres of a frequently flooded area, known as Tract
19, is owned by the City of Plainfield. The land is vacant and is
used by the City of Plainfield as a dump for construction debris and
street sweepings. The area is bounded by Terrill Road, Third Avenue,
Geneva Place and St. Nicholas Boulevard. - 77 - ELSON T. KILLAM ASSOCIATES, INC.
In 1968, Mr. Norman E. Gehri, then City Engineer of Plainfield, pro
posed to the City Council that Tract 19 be utilized as a storm water
detention basin. A preliminary investigation has been made to determine
the adequacy of this site to significantly reduce the peak storm flows
in Cedar Brook. The results of this investigation indicate that suf
ficient storage capacity could be developed at the site to reduce the
peak flow of a 15-year frequency storm approximately 350 cfs, or about
40%. The estimated 15-year frequency storm flow at Third Avenue and
Wiley Avenue is 755 cfs. The estimated capacity of the Cedar Brook
conduit at this location is only 400 cfs. Thus, with the construction of
the detention basin, the upper reach of the Cedar Brook conduit could
accommodate the 15-year frequency flow. The proposed basin would also
be effective in reducing the peak flows in downstream reaches. Flooding
due to storms of less than 15-year frequency in Cedar Brook would be
eliminated, and storms of greater than 15-year frequency would be
significantly reduced.
The construction of the basin would not preclude its use as a
park.
The detention basin would require a surface area of 12 to 15 acres,
and the bottom of the basin would have to be excavated to an average
elevation of approximately 116. This is 10 to 15 feet below existing
grades. However, the basin could be designed to be dry, normally, which
would make its use for athletic fields possible. A portion of the
excavated material could be used to fill and contour the remainder of
Tract 19 to enhance its use as a park. There are no parks in the
- 78 - ELSON T. KILLAM AS SOCIATES, INC.
immediate vicinity of this heavily developed residential area. The
development of a combined detention basin and park would not only
benefit the City uf Plaiufield but would also provide recreational
facilities for the residents of the neighboring areas.
The cost of the detention basin will depend upon the quantity of ma'.trial
that can be used as fill in the immediate site. A unit cost of approxi
mately $1.50/cubic yard would cover excavation if the material can be dis
posed of on the site. If the material must be removed from the site, the
cost could be as much as $4.50/cubic yard. However, if the material is
disposed of on site,it will require the removal of many existing trees
which is not desirable. It has been estimated that approximately 300,000
cubic yards of material will have to be excavated. If it is assumed that
half of the excavatiou will be removed from the site, the cost would be
approximately $900,000. Control structures and connections to the
existing Cedar Brook conduit would cost about $50,000 resulting in a
total construction cost of approximately $1,000,000.
The construction of the detention basin for $1,000,000 would provide
only slightly less flood protection that would be provided by the con
struction of the Second Cedar Brook Conduit for an estimated cost of
$5,000,000. The construction of the basin would also eliminate the
great interference of traffic that would be associated with the con
struction of the relief conduit through the center of Plainfield.
The financing of such a facility is probably beyond the means of the
City of Plainfield. It is recommended that the Union County Park Com
mission purchase the land and construct the detention basin and park
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facilities. The construction of the detention basin will eliminate
the need for the construction of the relief Cedar Brook conduit.
The benefits of this project will not be fully realized until Green
Brook is also improved. During heavy storms, when Green Brook overflows
into Cedar Brook, the effect to the detention basin at Tract 19 will be
minimal. However, when Green Brook can be confined to its channel,
Cedar Brook flooding will be greatly reduced by the construction of the
detention basin.
In the southern area of Plainfield the area in Cedar Brook Park and
some adjacent residential areas experience frequent flooding during heavy
rainfalls. The major cause of this flooding is the insufficiency of
the channel outlet downstream in Middlesex County. Intracounty and State
cooperation will be required to eliminate this flooding condition.
- 80 - ELSON T. KILLAM ASSOCIATES, INC.
THE RAHWAY RIVER - ESSEX COUNTY TO NOMAHEGAN PARK
The Rahway River drains approximately half of the land area of Union
County. The greatest peak storm flow of record recorded within the County
occurred on the Rahway River. The stream bed is quite steep in the upper
reaches in Essex County, which results in a short time of concentration
and high flows even though much of the land in the South Mountain Reser
vation is covered with timber. The east and west branches of the Rahway
River join one thousand feet above Morris Avenue on the Springfield-Union
Township Line. The tributary area at this location is approximately 17.2
sq. mi. The slope of the stream from this point to Route 22 is approxi
mately one foot per thousand feet. The average bank height and channel
width are about 5 feet high and 40 feet wide,respectively. A stream
gaging station is located south of Route 22, for which a peak flow
frequency curve has been developed and is presented on Exhibit XI. The
greatest flow of record at this station occurred on May 29, 1968, and
was determined to be 2,520 cfs. This storm resulted in river stage
elevations as much as six feet above the bank elevations. The source of
this information is the Union County Park Commission which has recorded
the Rahway River flood stages at selected locations for most major storms
since 1924.
The Union County Park Commission has acquired the strip of land
bordering the river throughout this reach which forms the Springfield
and Union Township boundary. The width of the park land varies from
200 feet to 1,000 feet and was acquired primarily to maintain the river
flood plain. The river channel is capable of carrying a storm water
- 81 - ELSON T. KILLAM ASSOCIATES , INC.
flow of approximately one to two year frequency without overflowing its
bank and approximately a two to three year frequency flow can be main
tained within the park land area. During heavier storms, extensive areas
of Springfield become flooded. The flooding is caused by overflowing of
the Rahway River and inadequate local streams and conduits.
A storm water flood study was canducted for the Township of Spring
field by Richard J. Jeske, Inc., Consulting Engineers, in October, 1969.
The study included an analysis of the existing problem areas of flooding,
and outlines preliminary plans for eliminating the flooding. The report
recommends improvement of the streams in the Township of Springfield as
shown on Exhibit XVII. The estimated cost of this stream improvement
work was $1,000,000. The lower reaches of all of these streams are af
fected by the water levels in the Rahway River during flood flows. As
the river stages in the Rahway River rises, surcharging occurs in local
streams causing them to overflow their banks. To eliminate this problem,
it was proposed that dikes be constructed with pumping stations to pump
local storm water runoff into the Rahway River during high stages of
river flow. The proposal recommends a major storm water pumping station,
the required capacity of which we estimate to be about 1000 cfs, located
on Van Winkles Brook with three or four smaller pumping stations to pump
local storm water flows into the river against higher river stages. The
report presented the following cost estimates for the pumping stations
and dikes.
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TABLE XV
SPRINGFIELD - PROPOSED RAHWAY RIVER FLOOD PROTECTION PROGRAM
Van Winkles Brook Pump Station $ 750,000
3 Small Pump Stations 450,000
Piping for Pump Stations 110,000
Dikes 90,000
TOTAL CONSTRUCTION COST $1,400,000
This estimate includes construction costs only and does not include en
gineering, legal, or construction contingency costs, which might add from
25% to 30% to the cost.
In addition to these fixed costs, the pumping stations will require
operation and maintenance expenditures which would range from $25,000 to
$50,000 per year.
The construction of the dike facilities will further confine the
Rahway River.
Union Township has not reported any major flooding along the Rahway
River; however, with the proposed diking on the Springfield side of the
river, the water surface level would be expected to increase, and it is
probable that this will increase the water surface and increase flood
levels in Union Township.
An alternative solution to the diking and pumping plan has been in
vestigated. This comprises the excavation of a deeper and wider river
channel for the main branch of the Rahway River. The improved channel
would begin approximately 3,300 feet downstream of U. S. Route 22 and
would extend upstream to a point about 1,000 feet above Morris Avenue.
The proposed channel would be designed to carry about 2,500 cfs, the
- 83 - ELSON T. KILLAM ASSOCIATES.IKC.
greatest flow of record and estimated to be in the order of 50-year
frequency. The channel would be trapezoidal with a base width of 100
feet, with a 2:1 side slope. By beginning the channel improvement
3,300 feet downstream of Route 22, an outlet for the deeper channel would
be obtained. Table XVI shows the estimated effect of the proposed channel
on the stream invert elevations and the estimated river stage with a
2,500 cfs storm flow.
TABLE XVI
UPPER RAHWAY RIVER CHANNEL IMPROVEMENT
Water Surface Elev. at 2 ,500 cfs Recorded Estimated Existing Following Location Invert Elev. Invert Elev. Channel Improvement
Route 22 65.0 63.6 75.5 69.3
Mi11town Rd. 67.5 65.6 - 71.3
Rahway Valley Railroad 72.5 68.8 82.4 74.5
Morris Ave. 76.0 72.0 86.4 79.7
The water surface elevations under the conditions of a 2,500 cfs flow would
be below those required for free discharge of the proposed Springfield
local collection systems, thereby eliminating the need for pumping stations.
There are five bridges which cross the Rahway in this reach. These are
at East Bound Rt. 22, West Bound Rt. 22, Milltown Road, Rahway Valley
Railroad and Morris Avenue (Rt. 82). All of the bridges are sufficient
for the proposed channel improvements except Morris Avenue and East Bound
Rt. 22, both of which are State highways. It has been recognized for
several years that the Morris Avenue bridge is insufficient, and the
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Township of Springfield has requested the State Department of Transporta
tion to replace this bridge.
The East Bound Rt. 22 bridge is also of insufficient area and capacity.
Preliminary hydraulic studies indicate that to pass the 2,500 cfs design
flow, the bridge would require a head water of approximately 1.5 feet.
This would surcharge the upstream channel to its bank level leaving no
free board. A cost estimate for the proposed stream improvement follows:
TABLE XVII
COST ESTIMATE UPPER RAHWAY RIVER CHANNEL IMPROVEMENT
Excavation 410,000 Cu. Yds. @ $3.50 = $1,430,000.00
Clear, Grub, Seed 55 acres @ $1600 = 88,000.00
Concrete Transitions at Bridges 8 @ $20,000 = 160,000.00
Sub-Total $1,678,000.00
Morris Avenue Bridge = 300,000.00
Rt. 22 East Bound = 300,000.00
Total Construction Cost = $2,278,000.00
25% Engineering, Legal, Construction Contingencies = 572,000.00
Estimated Total Cost = $2,850,000.00
To more readily evaluate the merits of this proposal, an estimate
was also prepared with the unit costs used to develop the estimate in
Table XV. The construction cost of the channel improvement not includ
ing the Bridges on this basis was estimated to be $1,572,000.00 as com
pared to the diking and pumping plan which would cost $1,400,000.00.
It is believed that the advantages of the channel improvement and the
saving in operation and maintenance costs will offset the additional
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initial expenditure. The replacement of the Morris Avenue Bridge and
Rt. 22 East Bound Bridge would eventually be required under a diking
and pumping scheme and therefore has been deleted from the comparative
cost estimates.
It is recommended that further detailed studies of this reach of the
Rahway River be undertaken. If the preliminary studies are verified, it
is then recommended that an improved channel be considered. Because this
improvement will benefit more than one community and will serve to accommo
date the flood flows from an adjoining County, the Corps of Engineers
should be made a party to the study and cost participation.
TOWNSHIP OF SPRINGFIELD
The improvement to the Rahway River will not eliminate all of the
frequent flooding in other areas in Springfield. As shown on Exhibit XV,
several streams experience flooding above the lower Rahway River eleva
tion. The severest flooding occurs along Bryants Brook, Van Winkles
Brook and Brown Avenue Branch. The Township of Springfield "Drainage &
Flood Control Study & Master Plan" recommends improvements which will
greatly reduce the frequency of flooding in these streams.
The head waters of Bryants Brook which are formed in the steep hills
of Summit and Millburn become flat streams when they reach Springfield
and the gradient becomes slight which retards the flow and causes flood
ing. Bryants Brook divides into two channels just South of Rt. 78. This
is shown on Exhibit VIII, between Analysis Location R-10 and R-ll. The
combined capacity of the two channels is not sufficient to pass even
storms of low intensity rainfall. The drainage plan calls for a major
improvement of the East Branch, designed to carry a storm flow of 770 cfs.
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The West Branch will be designed to accommodate 150 cfs estimated for a
storm of 15-year frequency. This proposed improvement should result in the
nominal cost since bridges and culverts will only have to be enlarged or
replaced on the East Branch.
It has been recommended that the replacement of the Caldwell Street,
Slater Street and Mountain Avenue Bridges on the East Branch of Bryants
Brook be undertaken. The Union County Engineering Department has budgeted
$156,000 for this work and has obtained matching funds from the State
to construct these three bridges which are planned to be undertaken in
1971.
Flooding of Van Winkles Brook above Wabeno Avenue is also caused
principally by inadequate channel capacity. The Springfield drainage
plan calls for the improvement of the stream channel from Hannah Street
to a point about 2400 feet North of Rt. 78. A vertical wall, concrete
lined channel and the enclosing of the stream to Millburn Avenue in a
corrugated metal pipe arch are proposed. It has been anticipated that
Millburn Township, in Essex County, would share in the cost of the im
provement beginning at the point where it forms a common boundary between
the municipalities. No County bridges have been recommended for replace
ment on this stream.
The Brown Avenue Branch, Stream 10-32, has also experienced frequent
flooding. The stream is formed in the Baltusrol Golf Club and flows
southeasterly into the Rahway River at Rt. 22, Analysis Location R-16.
The drainage plan generally calls for the widening of the existing
channels from Rt. 22 to a point 600 feet upstream of Springfield Avenue
and the stream above this point would be enclosed in a corrugated metal
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pipe arch section. It has been recommended that the Springfield Avenue
bridge on this stream also be replaced. The County should schedule such
replacement to coincide with the proposed channel improvement on this
stream by the municipality.
The reach of the Rahway River between Rt. 22 and the northern Spring
field Avenue Bridge in Cranford is very flat and has an extremely wide
flood plain. The Union County Park Commission's Nomehegan Park occupies
most of the flood plain which acts as a natural detention basin during
periods of storm flow and high river runoff. The channel section in this
reach does not have sufficient capacity for major storm flows and the
flood waters overflow the banks and pond in the Park area. The storage
of this water in the Park reduces the downstream flow and the resultant
flooding in the heavily developed downstream areas.
BOROUGH OF KENILWORTH
The Borough of Kenilworth is located in north central Union County on
the ridge line of the Rahway River, the Elizabeth River and Morses Creek.
Kenilworth had a "Drainage and Flood Control Improvement Program" pre
pared by Koczur Associates Consulting Engineers dated 1968.-^Four of the
five major streams in the Township were studied. The West Branch of the
Elizabeth River was not included, as it is located entirely in the
Galloping Hill Park and Golf Course area of the Borough and does not
present a flooding problem.
The four streams that were studied are Branch 10-31-1 (Black Brook),
Branch 10-24 and 10-30 of the Rahway River and Stream 9-1 (West Brook)
in the Morses Creek watershed.
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It was proposed to improve streams 10-24 and 10-30 by installing
concrete lined channels at approximately existing grades and to enclose
stream 10-31-1 in a 48" diameter reinforced concrete pipe. The report
states that all existing bridges on these streams are sufficient and tan
be incorporated into the recommended stream improvement program.
The improvements recommended for West Brook will be discussed in the
Morses Creek section of this report. In 1968, it was estimated that the
improvement of the four streams would cost about $864,000. and required
local collection facilities would cost an additional $1,200,000.
In addition to the stream work, the report recommended installation
of adequate storm sewers along Kenilworth Boulevard. The installation of
these facilities will eliminate the frequent flooding in this area except
during extreme storms when the Rahway River stage will surcharge the
local storm sewers.
RAHWAY RIVER - NOMAHEGAN PARK TO HIGH STREET
This reach of the Rahway River between Kenilworth Boulevard and the
northern Springfield Avenue Bridge in Cranford has no slope. The invert
elevation at Kenilworth Boulevard is 58.0' and is 58.0' at Springfield
Avenue.
The distance between these two locations is approximately one mile.
Because of the flat slope of the river bottom in this reach, the river
develops an extremely wide flood plain as the hydraulic gradient or
river level increases at the upstream end when flood flows occur.
Nomahegan Park occupies most of the flood plain, extending from Spring
field Avenue on the West to Riverside Drive on the East.
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During the flood of May 28, 1968, water was ponded in the park to a
depth of four feet, substantially reducing the downstream flow. However,
a residential area has been constructed within the natural flood plan East
of Riverside Drive. An earth berm has been constructed to prevent direct
innundation by the river. The dike has been constructed to approximately
elevation 68 and sumps have also been constructed to facilitate the use
of portable pumps during heavy storms to reduce water levels behind the
dikes. It has been reported that even with these measures, frequent
flooding still occurs. The elevation of Riverside Drive, directly behind
the dike, is three to four feet lower than the dike. It has been reported
that a five-year frequency storm results in two feet of water ponding
behind the dike and that on May 28, 1968, the river overtopped the dike
by 8 inches resulting in about four feet of water ponding in this resi
dential area of about 50 acres.
Two major storm drains, with a combined tributary area of 340 acres,
carry storm water runoff through this area to the Rahway River. When
the river stage is high, the flap gates close on the storm sewer outlet
into the river which forces the water to surcharge and pond in the low-
lying area along Riverside Drive.
There are two methods of preventing the flooding in this reach:
1. Increase the height of the dike protection and install
permanent storm water pumping facilities for local runoff.
2. Deepen and widen the Rahway River Channel.
To minimize flood flows and resultant storm water damage downstream
of Nomahegan Park, it is necessary that flood waters pond in this un
developed area. If an improved channel were installed north of the
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Kensington Avenue foot bridge, the detention basin would be destroyed.
For this reason, at least the area north of Kensington Avenue should be
protected by dike facilities. The local storm water runoff north of
Kensington Avenue can either be pumped into the river against high stage
or carried in an interceptor storm sewer to a point below Kensington
Avenue where it will be freely discharged into the river.
In the reach between Kensington Avenue and Springfield Avenue,
the entire flood plain has been encroached upon. The width between
Riverside Drive and the rear of the homes on the west bank is not much
more than about 100 feet. The water surface in this reach is controlled
by Hansel's Dam, 7000 feet downstream. The spillway crest is at elevation
59.2, while the road grade of Kensington Avenue is approximately 64.0.
To be able to provide a gravity outlet for the local drainage
facilities along Riverside Drive between Kensington Avenue and Spring
field Avenue, extensive work must be done in the river section between
Hansel's Dam and Kensington Avenue.
A brief description of the required work and the estimated costs
of the improvement have been included.
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TABLE XVIII
CRANFORD-RAHWAY RIVER IMPROVEMENT
Cost
1. Remove Hansel's Dam and Construct Inflatable Fabridam $ 135,000
2. Deepen and Widen Channel from Union Avenue to Southern Springfield Avenue Bridge (Base width = 120 earth lined) 112,000
3. Construct New River Channel Along Springfield Avenue (Base width = 70' side slope = 1.5:1 concrete lined) 896,000
A. Improve Channel from Northern Springfield Avenue to Kensington Avenue (Base width = 70' side slope = 1.5:1 concrete lined) 684 ,000
Construction Total $1,827,000
25% Engineering, Legal and Construction Contingencies 473,000
Total $2,300,000
The improvements outlined above are required to provide gravity discharge
of storm sewers in the Riverside Drive area and to eliminate the flooding
between Union Avenue and Kensington Avenue. The existing channel is
capable of carrying a one-year frequency storm of approximately 1000 cfs.
A design flow in the order of 3000 cfs, 50-year frequency, is recommended.
To keep the water surface within the river banks at this flow rate, it
would be necessary to remove Hansel's Dam. During the May 28, 1968
storm, the elevation of the water surface immediately above the dam was
68.0' which is also the elevation of the top of the dike 7000 feet up
stream, at Kensington Avenue. The recreational value of the pond above
Hansel's Dam could be retained by replacing the existing concrete structure
with a "Fabridam", or inflatable dam. During dry weather periods, the
dam would be inflated to maintain a pond upstream and when storm flows
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were expected, the dam could be slowly deflated to pass the storm flow
without creating an appreciable backwater affect. There are several
installations of these dams in the Los Angeles area and in Pennsylvania
that have been operated successfully. The design flow of 3000 cfs would
pass over the deflated dam with a water surface elevation of approximately
64., four feet lower than with the existing structure.
It is also suggested that a new river channel section be constructed
along the east side of Springfield Avenue. This new channel would shorten
the length of this reach by 2500 feet, and increasing the available slope
by 35%. This alignment would require the acquisition of six properties
but would result in a significant savings in normal channel improvement
cost. The Springfield Avenue Channel would be 800 feet long, with bridges
at Orange Avenue and Normandie Place. The channel would be trapezoidal
in shape with a 70-foot base width and a concrete lining. A channel
of the same size would be extended upstream to Kensington Avenue. Pro
visions could be made to relocate the canoe rental facility and to pre
serve the existing stream channel for that recreational use.
The proposed improvement to this reach of the Rahway River is diffi
cult because of the extremely flat slopes, limited flood plain, low
river banks, Hansel's Dam and the density of development in the area.
Interim or local improvements would be of extremely limited benefit
along this reach. Major expenditures would therefore be required to
eliminate the frequent flooding in this area of Cranford.
There is a major stream which is tributary to the Rahway River
between the two Springfield Avenue Bridges. Branch 10-26 is formed in
Westfield and flows through Cranford to the Rahway River. Frequent
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flooding occurs along this stream at Harding and Coolidge Streets in
Westfield and along the lower reaches just above the confluence.
The flooding in Westfield is caused primarily by insufficient
channel capacity in the reach between Coolidge Street and Brookside
Place in Cranford. The correction of this problem will require a major
regrading and realigning of the stream. The flooding in the lower reaches
of Stream 10-26 is caused by insufficient channel capacity and backup
from the Rahway River. The recommended improvements previously described
for the mainstem of the Rahway River will help reduce the frequency of
flooding in the lower areas.
Flooding along the Rahway River in Cranford has also been reported
to have occurred on Lincoln Parkway. It appears that this flooding has
been caused by insufficient channel capacity combined with the backwater
or surcharge created by Droescher's Dam above High Street. The removal
of this dam and the construction of an earth lined channel about 120 foot
wide would be required to resolve this problem. If it is desired to
maintain the pond, an inflatable "Fabridam" could be provided. The
estimated total project cost of the improved channel required and the
"Fabridam" structure would be about $400,000.
BOROUGH OF GARWOOD
Stream 10-25 is also formed in Westfield but flows through Garwood
and then Cranford until it reaches the confluence with the Rahway River
between the two Eastman Avenue bridges. The upper reaches of the stream
in Westfield are all piped and no major flooding has been reported.
However, after the stream is carried under the Central Railroad of New
Jersey, it flows through an open channel which has experienced frequent
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flooding in both Westfield and Garwood. The cause is believed to be
both inadequate channels and bridges. The extremely flat slopes in this
area make it necessary to conduct a detailed field survey and hydraulic
analysis to determine the cause and find the best solutions of this
condition.
BOROUGH OF MOUNTAINSIDE
Nomahegan Brook, a major tributary of the Rahway River, drains most
of Mountainside and a portion of Springfield, Westfield and Cranford.
The lower portion of the brook lies within Nomahegan Park and Echo Lake
Park. The reach of the Brook in the Park area is relatively flat while
the upper reaches in Mountainside are steep.
There are four streams which drain the tributary areas of Mountain
side into NQmahegan Brook. All of these streams have experienced flood
ing and are susceptible to erosion because of high velocities. The
Borough of Mountainside has a "Feasibility Study and Report for Storm
Drainage Facilities" prepared by Elson T. Killam Associates, Inc.,in
1962. The plan outlines a program for the improvement of these streams
which would reduce flooding and control erosion.
A staged program has been undertaken by the Borough in conformance
with the recommendations with improvements of two of the four streams
having been initiated. Within the last three years, approximately
$300,000 has been spent for stream improvements in the Borough of
Mountainside. The improvements have been undertaken by the Borough of
Mountainside as local improvements. The remaining work required to
complete these improvements has been estimated to cost approximately
$900,000.
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Certain frequently flooded areas may require relief through improve
ments required of the County.
These include the New Providence Road Culvert, County Bridge No. 2,
on Nomahegan Brook at nalysis Location R17. The existing culvert has
approximately one-half the required capacity and must be replaced to
eliminate flooding at this location. In addition, at Central Avenue,
County Bridge No. 25, Analysis Location 19, the existing bridge has only
one-half of the required capacity to prevent local flooding. In addition,
stream improvement is also required on this branch and the County culvert
enlargement should be scheduled to coincide with the stream improvement
which will be undertaken by the. municipality.
At Mountain Avenue, one block south of New Providence Road, flooding
has been reported to depths of one foot on Mountain Avenue at least once
a year on this County road. This flooding is caused by inadequate
culvert capacity and should be considered for enlargement by the County.
Branch Number 10-29-1-1 of Nomahegan Brook is formed in Mountainside
and discharges into the Township of Springfield above Briar Hills Circle
near Baltusrol Golf Club. In 1967, Mountainside undertook major drainage
improvements to reduce local flooding in the area of Charles Street in
the Borough. The storm sewers downstream in Springfield were recognized
to be inadequate at that time and to cause backwater and subsequent flooding
in the Borough of Mountainside under extreme flood flow condition. The
report and study for the Township as outlined in the Springfield "Drainage
and Flood Control Study and Master Plan1 recommended the improvement of
this stream from Mountain Avenue downstream to Nomahegan Brook. However,
improvements were not recommended for the section of the stream from
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Mountain Avenue upstream to the Borough of Mountainside line. The
capacity of the existing culverts should be at least twice the present
capacity to provide for relief from flooding in the Borough of Mountain
side. Storm water relief will be required in the area to eliminate
flooding of localized areas under conditions of heavy rainfall.
State Highway Rt. 22 passes parallel to the high land areas of
Mountainside. Generally, the drainage facilities under the highway at
the major stream crossing are adequate to handle the estimated runoff
from the major storm flows. However, there are two areas at which the
highway facilities are inadequate. During relatively high intensity
rainfalls, ponding of water occurs at locations where the capacity of
the highway drainage system is limited and creates interruption to travel
on this major State highway. These frequently flooded areas are located
to the east and west of the Mountain Avenue traffic circle. A critical
flooding area is located at the eastern end extending from the traffic
circle to the Springfield Road intersection. It is important that this
major artery be kept passable, and since this is a State highway, the
Department of Transportation should be requested to correct this condi
tion by enlargement of the storm sewers and to provide adequate capacity
so as to pass flood flows frequently encountered.
Few flooding problems have been reported in the main branch of the
Rahway River from High Street in Cranford to St. Georges Avenue in
Rahway. The water surface in this reach is controlled by three dams.
Even during peak storm flows the dams create ponding which is almost
entirely limited to park lands. Generally the only work which may be
justified in this reach is channel desnagging and desilting.
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THE LOWER RAHWAY RIVER IN THE CITY OF RAHWAY
In the City of Rahway the two largest tributaries of the Rahway River
join the main branch of the river near the tidal estuary. Much of the
land area of the City of Rahway is low and experiences flooding by high
storm water runoff and high tides.
A study of the flooding conditions adjacent the streams in the City
of Rahway was undertaken by Frank H. Lehr Associates in 1967. This
report entitled, "Rahway River Drainage System Study of Potential Flooding",
describes in detail the prevailing flooding problems along the river and
its tributaries. The main branch of the Rahway River, between St. George
Avenue and the confluence with Robinson's Branch, is located within the
Union County Park Commission property. It has been reported that flooding
extends beyond the park limits to adjacent roadways and private properties.
However, this condition is reported to be an infrequent occasion and not
too extensive except in the area of Alien Street.
The Alien Street and Union Street intersection is located in a
depression which is slightly above the banks of the river. The Alien
Street and West Grand Avenue intersection is below elevation 10 feet and
has been reported to flood frequently. The situation is aggravated by
overflow from a combined storm sewer which runs through this area.
During dry weather conditions the combined storm sewer carries dry
weather flow (sewage) under the river to the Rahway Valley Sewerage
Authority trunk sewer which is located on the east bank of the river.
During heavy rainfalls the combined sewer becomes surcharged and
overflows into the Newton Street and Alien Street area.
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Frequent flooding conditions have resulted in the general deterioration
of this entire area.
The Union County Park Commission has proposed to acquire the major
portion of this frequently flooded area, east of Union Street. The
report for the City of Rahway furthermore recommends that the Park
Commission also acquire the properites on Alien Street on the block
between Union Avenue and West Grand Avenue, and, in addition, the pro-
perities on the west side of Union Street. The acquisition of these
properties will make it possible to fill the low-lying area and sub
sequently eliminate or at least reduce the frequency of flooding. The
present plan of land acquisition would not necessarily eliminate the
depression at the Union Avenue and Alien Street intersection which would
be desirable.
The main branch of the Rahway River from Edgar Road to the Arthur
Kill has a wide and, generally unimproved, flood plain. It has been
determined by the U. S. Army Corps of Engineers that this reach of the
Rahway River does not presently warrant extensive improvements. We
agree with this conclusion and suggest that local areas be protected
by filling of low-lying areas where possible. It will be the responsi
bility of the County and the local government to ensure that a
reasonable flood plain be maintained along the river where low-lying
areas are subject to inundation under high tide and peak storm flow
conditions.
Two small streams are also tributary to the main branch of the
Rahway Rivter in this area. These streams, designated Stream 10-8 and
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Stream 10-9, originate in Linden and flow through the City of Rahway
where they discharge into the Rahway River. Stream 10-8, located im
mediately North of Elizabeth Avenue, has a tributary area of 220 acres,
132 acres of which are located in Linden. Frequent flooding has
reportedly occurred along this stream, both in Linden and Rahway. The
flood control long-range program in the City of Linden calls for the
installation of relief sewers along this stream to eliminate the frequent
flooding at Stiles Avenue, Dalziel Road, Cantor Avenue and Hurst Street.
The installation of these facilities by Linden will not be entirely ef
fective in eliminating flooding until the City of Rahway undertakes
improvements in the downstream reach of Stream 10-8. The report to the
City of Rahway also recommends the improvement of this stream. Including
the replacement of the five bridges downstream of Whittier Street. .In
addition, a 48" diameter storm sewer from Whitti3r Street to the Linden
line has insufficient capacity and must be replaced or paralleled to pro
vide adequate drainage from the City of Linden. County assistance may
be required to expedite this improvement.
Stream 10-9, located immediately North of St. Georges Avenue in
Linden also requires improvement. Frequent flooding occurs in Linden for
the entire length of Academy Terrace. The flood control improvement plan
for the City of Linden flood control calls for the installation of a
relief storm sewer to serve the tributary areas of about 304 acres. The
plan calls for the construction of a 72" diameter outlet storm sewer
which would connect with the existing 72" diameter storm sewer located
in the City of Rahway.
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In the City of Rahway flooding has been reported to have occurred
downstream of Apgar Terrace. This flooding is caused primarily by the
high stages in the Rahway River under periods of high river flow. It
has been recommended that the low-lying areas be filled to reduce and
eliminate this flooding.
The South Branch of the Rahway River, Stream 10-6, is one of the
two major tributaries in the City. The stream lies primarily in
Middlesex County and has a tributary area of 9.6 square miles at the
location where it enters Union County. The entire reach within the City
of Rahway is influenced by the tide in Arthur Kill. The natural low-
lying flood plain of the river, extending from West of Main Street to
East of Leesville Avenue, has been affected by major encroachments.
The Corps of Engineer's Survey Report for Flood Control at the Rahway
River states that major and costly flood control facilities are not
warranted along this stream. This may be attributed to the fact, that the
close proximity of buildings adjacent the stream channel require the
construction of concrete flood walls rather than the less-expensive
earth dikes. Much of the private property along the stream is below
elevation 10 feet and is susceptible to flooding from both frequent
storm water runoff and tidal inundation.
The acquisition of the properties along the stream, particularly
East of Inman Avenue, will eliminate further encroachment upon the flood
plain and would make possible the future construction of dikes. This
property acquisition might be considered by the Union County Park
Commission. The land could be utilized for recreational purposes until - 101 - ELSON T. KILLAM ASSOCIA TES TN C
flood control facilities in this area are economically justified.
A tributary of the South Branch of the Rahway River, Stream 10-6-2,
also experiences extensive flooding. This stream joins the South Branch
of the Raritan River at Analysis Location R-58. The primary cause for
the flooding along this stream is the inadequate sized culverts under
the Pennsylvania Railroad and at New Brunswick Avenue. The report to
the City of Rahway recommended the enlargement of inadequately sized
culverts as well as the improvement of the open channel sections of
this stream. These improvements will significantly reduce the frequency
of flooding in this area. There are several bridges along this stream
which are of marginal capacity and will aggravate flooding during
storms of severe intensity.
The older areas of the City of Rahway, generally defined as the area
east of St. George Avenue and west of the main branch of the Rahway
River, are served by a combined storm sewer system. During dry weather
periods the sewers carry the sanitary waste to the Rahway Valley
Sewerage Authority interceptors for delivery to the treatment plant.
However, during periods of heavy storm water flows, the same sewers
must carry, in addition to the sanitary sewage waste, the storm water
runoff. In general, the combined sewers are inadequate to carry the
storm water flows. As the combined sewers become surcharged during
periods of heavy rainfall because of inadequate capacity, they overflow
into the streets in this densely populated area.A program to separate
the combined sewers from the sanitary sewers and to provide adequate
local storm drainage in this area should be considered.
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Robinson's Branch is the largest tributary stream of the Rahway River.
The tributary area at the mouth where it discharges into the Rahway River
is 22.5 square miles. The development of this watershed prior to 1950
was rather nominal. With the rapid growth and development of the tributary
area, this watershed has approached concentrated development. As a
result, it can be expected that the storm flows will continue to increase,
resulting in more frequent flooding.
The Union County Park Commission originally contemplated a continuous
river parkway along Robinson's Branch as well as along the main branch of
this river. Milton Lake Park and Veterans Field are portions of the
long-range plan for park land development along Robinson's Branch.
Acquisition of the remaining land has not been completed and in some
areas, encroachment of the low-lying areas by development has occurred.
Prevention of flooding of existing structures located within the flood
plain will be extremely expensive. The U. S. Army Corps of Engineers
has determined that substantial improvements cannot be justified. The
report to the City recommends that only limited local improvements be
considered with emphasis on the replacement of the two bridges considered
to be inadequate on Irving Street and Central Avenue.
It is our opinion that a continued effort be made by the Union County
Park Commission to obtain all property within the flood plain of this
stream. The cost of providing flood protection facilities for the reach
of Robinson's Branch between Madison Avenue and Irving Street would be
very costly. The cost would be high for the following reasons: limited
channel width caused by flood plain encroachments would require costly
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enlargements, numerous bridges of Inadequate or marginal capacity would
have to be replaced, and the combined effect of peak storm runoff and
tidal influence could still cause flooding following these improvements.
A detailed field investigation and hydraulic analysis is required to
determine the most economical method of improvement.
There are approximately 7,000 feet of stream between the southern end
of Milton Lake Park and the confluence with the main branch of the Rahway
River requiring improvement. If a 125 foot wide right-of-way were
available, an earth lined channel could be constructed for a cost of ap
proximately $700,000. In addition, the replacement of at least two
bridges will be required at a minimum cost of at least $300,000. Thus,
the minimum cost to substantially reduce the frequency of flooding along
this reach of Robinson's Branch has been estimated to be about $1,000,000,
exclusive of land acquisition cost. The entire 125 foot wide right-of-way
may not be available, in which case a concrete-lined channel would be
required and this would substantially increase the cost of this channel
improvement. The construction of a flood detention basin upstream of the
City of Rahway could reduce the size of the channel cross section required,
and this alternative will be discussed in a later section of this report.
Stream 10-7-2 is tributary to the Rahway River at Maple Avenue in
Rahway. The total tributary area of this stream is about 200 acres, of
which 100 acres are located in the Township of Clark. In the Township of Clark, it has been reported that flooding to a depth of two feet in
Washington, Station and Harrison Streets occurs on the average of about
once yearly. The cause of this flooding is attributed to insufficient
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channel and conduit capacity in both Clark Township and in the City of
Rahway. Along this stream flooding in the City of Rahway has been
reported from Milton Boulevard to the mouth of the river. To alleviate
the flooding problem in Clark Township, it will be necessary to increase
the capacity of the drainage facilities in the City of Rahway. In many
areas where flooding occurs in adjoining areas of more than one munici
pality, joint action is required by both municipalities simultaneously
to afford complete relief from flooding. Cooperative action in these
undertakings is obviously necessary, and planning toward such action
shall be encouraged.
UPPER ROBINSON'S BRANCH
The reach of Robinson's Branch above the Middlesex Water Company dam
has not presented flooding problems of serious concern prior to the past
decade. Extensive development, however, has occurred within the water
shed in recent years and residential development has occurred in low-
lying land areas adjacent to streams where land areas had previously
been considered marginal. This has occurred in the Township of Clark
along Robinson's Branch and Pumpkin Patch Brook and in Scotch Plains
along Winding Brook. Robinson's Branch has practically no slope for a
reach of about one and one-half miles between the northern end of the
reservoir and Pumpkin Patch Brook in Clark Township. The bank height
is only about four feet high which results in frequent flooding of
adj oining lands.
A great deal of controversy has arisen concerning the effect of the
Middlesex Water Company dam upon the backwater and consequent flooding - 105 - ELSON T. KILLAM ASSOCIATES, INC.
in Westfield, Clark and Scotch Plains. The crest of the dam spillway
is at elevation 44 feet, and the elevation of the water surface in the
reservoir above the dam under a five-year and fifteen-year storm flow
condition has been estimated to be about elevation 46.3 feet and 46.7
feet, respectively. The stream invert and bank elevations at key
locations along this stream are tabulated below.
TABLE XIX
Profile of Robinsons's Branch Above Middlesex Water Company Dam
Invert Bank Elev. Elev.
1. Stream 10-7-15, R-48, Lamberts Mill Road, Westfield 43.0 46.0
2. Robinson's Branch opposite Northeast end of Stonehenge Terrace, Clark 43.0 47.0
3. Winding Brook, R-45, Lehigh Valley Railroad, Scotch Plains 43.4 47.0
4. Robinson's Branch, R-41, Old Lake Avenue, Clark 44.0 50.5
5. Robinson's Branch, R-40, Pumpkin Patch Brook 44.2 48.0
Under existing conditions, it is believed that during storms of from
five to fifteen-year frequency, the Water Company dam affects the water
surface in the stream up to a point at the downstream side of Lamberts
Mill Road and extending to a point opposite the northeastern end of
Stonehenge Terrace on Robinson's Branch. The water surface at other
locations is generally controlled by the channel sections and the
Goodman's Crossing Bridge which are recognized to be inadequate. If
enlarged channels were constructed and the Goodman's Crossing Bridge
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eliminated or replaced, the Middlesex Water Company dam could still
influence the water surface at the locations listed in Table XIX. The
degree of influence or control depends upon the magnitude of the storm
and extent of stream improvement.
To prevent surcharing of Pumpkin Patch Brook, the water surface
elevation at the confluence with Robinson's Branch should not exceed
elevation 50 feet. The water surface at the northern end of the reservoir
during a fifteen-year frequency storm is estimated to be elevation
47.7 feet. Thus, the available slope would be 2.3 feet in approximately
8,000 feet, or 0.00029 ft./ft.
To pass 2560 cfs, estimated to be a fifteen-year frequency storm
flow, an earth channel with a 120 feet base width, 2:1 side slopes and
a normal depth of approximately 7 feet would be required. This channel
would require a right-of-way width of approximately 170 feet.
However, development within the flood plain has now restricted the
available right-of-way to a width of 125 feet in the area east of Lake
Avenue. Several alternative plans for improvement were studied. Table
XX summarizes the results of these studies.
Alternative Nos. 1, 2 and 3 were based on natural flood flows and
with no modification to the Middlesex Water Company dam. Two alternative
proposals were also considered which might result in a greater economy.
Neither proposal would eliminate the need for some channel improvements,
but would reduce the size and cost of the channel improvements.
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TABLE XX
Cost Comparison for the Improvement of Robinson' s Branch, from The Middlesex Water Company Reservoir to Pumpkin Patch Brook
Water Surface Elev. Improvement at Pumpkin Patch Brook Cost
1. a. 8,000 feet of Earth Channel 50.9' $730,000 Base width = 85 feet
2. a. 6,000 feet of Earth Channel Base width = 120 feet b. 2,000 feet of Earth Channel Base width = 85 feet 50.2' $1,000,000
3. a. 6,000 feet of Earth Channel Base width = 120 feet b. 2,000 feet of Concrete Channel Base width = 85 feet 49.6' $1,900,000
4. a. Flood Detention Basin in Ash Brook Swamp b. 8,000 feet of Earth Channel Base width = 85 feet 50.0' $900,000
In the past, it had been suggested that a new outlet works be con
structed at the Middlesex Water Company dam to reduce the water surface
elevation in the reservoir during storm flows. This was generally
believed to be the expedient solution to the flooding problem in tributary
areas in Clark. However, the release of the water detained behind the
dam would worsen the already critical flood conditions downstream in the
City of Rahway and would not eliminate the necessity for channel improve
ments above the reservoir. For this reason, and because of the great
cost of outlet works at the dam, this proposal is not satisfactory.
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The recommended plan comprises the construction of a detention basin
on Robinson's Branch in the County Ash Brook Swamp Reservation. Ash
Brook Swamp is located in Scotch Plains, immediately upstream of Pumpkin
Patch Brook and the Lehigh Valley Railroad. By constructing a retention
basin in Ash Swamp it would be possible to reduce the peak storm flow of
the fifteen-year frequency storm from 2560 cfs to 2000 cfs, and an 85-foot
base width channel could be utilized which would provide the desired water
surface elevation of 50 feet at the mouth of Pumpkin Patch Brook. The
Ash Brook Swamp Reservation covers an area of approximately one square
mile. A portion of the reservation contains a golf course which should not
be flooded. The lowest green elevation is approximately 56 feet with some
fairways as low as elevation 54 feet. There are also a few private
properties along Lake Avenue with areas below elevation 52 feet.
For this reason, it is suggested that the water surface be kept
below elevation 52 feet.
During storms of one-year frequency or greater, the water surface in
the reservation is generally controlled by the restricted downstream
channel and Old Lake Avenue Bridge. These restrictions also create high
water conditions at Pumpkin Patch Brook. During the May 28, 1968, storm,
the greatest storm of record on Robinson's Branch, the water surface
elevation at the Old Lake Avenue Bridge was recorded 52.8 feet. With
the existing channel, this would result in a water surface of approximately
54 feet in Ash Brook Swamp. To optimize the effect of this natural
detention basin, two improvements are required. First, the existing
channel between the swamp and the Middlesex Water Company Reservoir
must be improved. This improvement is required to obtain a reasonable - 109 - ELSON T. KILLAM ASSOCIATES, INC.
water surface at Pumpkin Patch Brook and to reduce the elevation of the
water surface in the swamp created by the restrictions in the present
channel. Second, a control structure is required upstream of the Lehigh
Railroad to limit the flow rate to the proposed capacity in the downstream
channel. The proposed control structure would be designed to pass low
storm water flows with a minimum amount of backwater, thereby saving the
available storage for higher storm flows. It has been estimated that the
storage volume between elevation 50 feet and 52 feet would be 537 acre
feet or 175,000,000 million gallons. Effective use of this storage
capacity could result in substantial storm flow reduction in the down
stream channel extending to the mount of Robinson's Branch in the City
of Rahway.
To obtain the most economical and effective flooding protection program
along this stream from Rahway to Scotch Plains, the entire basin and
channels should be studied and work undertaken simultaneously. To
accomplish this, an authority or agency representing the interested
niunicipalites, the County and the State and Federal Government should be
considered in order to implement and finance the cost of these required
improvements.
TOWNSHIP OF CLARK
Clark Township is located along Robinson's Branch north of the
City of Rahway. The Middlesex Water Company dam is located on Robinson's
Branch and controls the water surface in the stream channel for a
distance of approximately two miles upstream. No major flooding in the
reach between the dam and north end of the reservoir was reported to
have occurred. ELSON T. KILLAM ASSOCIATES, INC.
Three minor areas of flooding can be resolved by Clark Township with
County assistance at critical road crossings.
The most severe flooding in Clark Township occurs along Pumpkin
Patch Brook, Stream 10-7-18. Pumpkin Patch Brook enters Clark from
Woodbridge Township, Middlesex County, with a drainage area of approxi
mately 1.75 square miles.
In a report titled, "Preliminary Report Upon Storm Drainage and
Sanitary Sewerage Facilities in the Township of Clark", Elson T.
Killam Associates, Inc., recommended that Pumpkin Patch Brook be improved
to carry the flow of a 15-year frequency storm. This was estimated to
be 850 cfs at the County line and 1000 cfs at the confluence with
Robinson's Branch. In addition to handling the estimated flood flows,
the report gave another reason for improving the stream channel.
Woodbridge Township was planning to increase the capacity of the section
of Pumpkin Patch Brook located within Woodbridge which would result in
increased flood flows in Clark Township. The Woodbridge stream channel
improvement has been made. Within Clark Township, a major bridge re
striction at the Oak Ridge Road has delayed the construction of an im
proved channel which has been proposed. The Union County Highway De
partment is presently completing construction of a new bridge at this
location, which will now enable the Township of Clark to make the required channel improvements.
A tributary stream to Pumpkin Patch Brook, which enters Clark from
Edison Township in Middlesex County, is also being enclosed under a
contract recently awarded by Clark Township, and it is anticipated that
the remainder of the improvements recommended for Pumpkin Patch Brook
- Ill - ELSON T. KILLAM ASSOCIATES, INC.
will subsequently be undertaken in the near future. The cost of the
proposed improvements has been estimated to be about $500,000.
TOWN OF WESTFIELD
Stream 10-7-15, a major tributary of Robinson's Branch, drains 2.68
square miles of area located in the Town of Westfield. The upper reaches
of this stream, above Analysis Location R-46, are entirely enclosed
and no flooding has been reported in this reach. Downstream of Shacka-
maxon Drive, the conduits discharge into an open channel. The stream
runs in backyards, and occasional flooding of streets and residential
areas occur along Knollwood Terrace. Downstream of Willow Grove Road,
the stream flows through Tamaques Reservation to Lamberts Mill Road.
Flooding has been reported in this area during heavy storms. This has
been attributed to the limited capacity of the existing bridges, silting
of the channel, and surcharge from the Middlesex Water Company dam upstream.
The channel invert elevation at this point is 43.5' while the crest of
the dam is at an elevation of 44'.
In 1969, the Water Company removed one-foot high flash boards from
the dam which has resulted in a lowering of the water elevations in the
reservoir by one foot. This has helped to reduce the frequency of flood
ing at Lamberts Mill Road. Periodic maintenance of the channel, as has
been produced in the past, has been helpful in reducing flooding. The
Lamberts Mill Road and the Lehigh Valley Railroad bridges are of marginal
capacity. Their widths are somewhat inadequate resulting in a rise in
the water surface upstream. This causes only minor problems, but in the
future, as development in this area becomes more pronounced, improvements
may be required.
- 112 - ELSQN T. KILLAM ASSOCIATES, INC.
TOWNSHIP OF SCOTCH PLAINS
Approximately eight square miles in the Township of Scotch Plains
are drained by Robinson's Branch. A comprehensive analysis of this
entire stream was made for the Township by Elson T. Killam Associates, 15 Inc., in 1963. The stream experiencing the most frequent and extensive
flooding in the southern portion of Scotch Plains is Stream 10-7-17.
This stream is formed in Westfield, and joins Robinson's Branch at
Analysis Location R-45. There are two reaches of this stream, known
as Winding Brook, which experience frequent flooding.
The first reach extends from Broad Street to Hetfield Avenue. A
preliminary design for a stream improvement in this reach has been com
pleted and comprises an improved channel section with a new bridge at
Hetfield Avenue. The bridge at Broad Street is of marginal capacity even
with the full area of the bridge available. Substantial silting has
occurred in this structure and comprises a restriction in the flow. The
improvement of the channel section upstream and downstream of the Broad
Street culvert should reduce the silting problem. The replacement of the
Broad Street Bridge is not recommended at this time, as the channel section
improvements are of paramount importance.
The second area that experiences frequent flooding in the Township
is along Winding Brook Way, upstream of the Lehigh Valley Railroad.
Flooding is caused in this area primarily because of insufficient channel
capacity. The design of channel improvements for this reach has been com
pleted and construction is scheduled for this improvement in the near
future. It is anticipated that the frequency of flooding in this area
will be greatly reduced. However, during extreme storms the backwater
- 113 - ELSON T. KILLAM AS SOCIATES, INC.
from Robinson's Branch and the constriction of the Lehigh Valley Rail
road culvert may still cause some limited flooding for very short
periods. The improvements recommended for Robinson's Branch will reduce
the frequency of flooding in the Winding Brook area by eliminating the
backwater during storm flows.
Flooding has also been reported in Scotch Plains at several loca
tions along Stream 10-7-22-1 between Cooper Street and Martine Avenue.
The stream channel is insufficient in some areas, and preliminary plans
have been prepared for channel improvement. It is anticipated that this
stream improvement work will be undertaken as funds become available.
Stream 10-7-22 is formed in Plainfield and Fanwood and flows through
Scotch Plains into the Ash Brook Swamp at Analysis Location R-35. Some
flooding occurs along several branches of this stream. Attempts have
been made to reduce flooding along this stream by local improvements.
A flood detention basin has been constructed by the City of Plainfield
above Analysis Location Number R-34. The basin is effective in reducing
downstream flows. It was recommended in 1958 that this basin be construc
ted in lieu of a channel improvement. Three alternate channel improve
ments were presented for the 2850 feet of channel in Plainfield and are
shown below with the 1971 estimated construction cost.
Estimated 1971 Construction Cost
1. Enclosed Box Culvert $1,200,000
2. Concrete Vertical Wall Channel $ 900,000
3. 1100' of Vertical Wall Channel 1750' Earth Lined Channel $ 500,000
- 114 - ELSON T. KILLAM ASSOCIATES, INC.
The design basis for each of these improvements was the 20-year fre
quency flow. Because of additional development along the stream the third
alternate is probably no longer applicable and a channel cost of at least
$700,000 would be anticipated. This improvement would probably not be
effective unless Scotch Plains also improved their reach of this stream.
The preliminary plans for the improvement of the Scotch Plains reach have
been completed but construction is not anticipated before 1980.
Severe flooding occurred along the reach of this stream between Sterling
Street and the Plainfield line prior to the construction of the retention
basin. The retention basin has greatly reduced the frequency and degree of
flooding in this area. It is, therefore, imperative that the basin be pre
served at least until downstream improvements are made in both Plainfield
and Scotch Plains.
Preliminary plans have been prepared for the improvement of Branch
10-7-22 from Raritan Road to the City of Plainfield line. This improve
ment would reduce much of the flooding and permit further improvements
of local streams which discharge into Branch 10-7-22. In September of
1964, the recommended improvements to Streams 10-7-17, 10-7-22, and 10-7-22-1
were estimated to cost $475,000. Local improvements required on the south
side of Scotch Plains were estimated to cost an additional $440,000.
The improvement of two reaches of Branch 10-7-17 is scheduled to
begin in the near future and some of the local improvements have been
made. In the Township of Scotch Plains a long-range plan of drainage
improvements has been planned. County assistance will be required for
some of this work.
- 115 - ELSON T. KILLAM AS SOCIATES, INC.
ELIZABETH RIVER IMPROVEMENT
The Army Corps of Engineers has proposed the improvement to the
Elizabeth River from Trotters Lane, at the Union line, to South First Street in
Elizabeth. The project is designed to reduce the flooding of the de
veloped areas bordering the river. The estimated annual average flood
damage is $605,000.
The project design flow is 5,900 cfs (about 10 percent greater than
greatest flow on record). The recurrence interval of a storm of this
magnitude has been estimated to be approximately once in 125 years.
The top elevation of sea walls and levees have been set to afford pro
tection against a tide elevation of 11.6, which will occur once in
about 140 years. This high degree of protection is believed to be
warranted by the Corps of Engineers because of the extent and value of
the property protected.
The general plan of this project is shown on Exhibit XVII. It con
sists of levees (earth embankments) and flood walls (concrete retaining
walls) with a 60-foot channel base width extending from South First
Street upstream to Bridge Street. The proposed wall-type of construc
tion is generally more costly and has been limited to areas where
existing structures are so close to the stream bed that earth levees
cannot be constructed. Exhibit XVIII shows the typical cross sections
for each of these types of improvements. The construction of levees
and flood walls will allow the water surface in the channel to be
higher than the adjacent land surface. Thus, pumping stations will be
required to pump local storm water runoff into the river channel.
- 116 - ELSON T. KILLAM AS SOCIATES , INC.
Storm water pumping stations are proposed to be located at South First
Street, Trenton Avenue, South Street and Bridge Street. These pumping
stations and the ponding areas associated with each are designed to
limit the flooding behind the levees to unimproved land. The most re
cent cost estimate for this project is $20,000,000, and has been esti
mated to require five years to construct. Union County is obligated
to reimburse the Federal Government for the cost of replacing all
bridges. As the first stage of the project, the Corps of Engineers
has recommended the replacement of three bridges at Summer, South and
Bridge Streets. Union County has allocated $350,000 in their 1971 bud
get for this work and has obtained matching funds from the State Aid
Road System Act of 1967 "Grant-In-Aid" Program. Thus, a portion of
this project will be constructed in the near future.
A concrete flume section, as illustrated on Exhibit XVIII, will be
constructed from Bridge Street to Trotters Lane. The channel base
width above and below West Grand Street is proposed to be 40 feet and
50 feet respectively. Twelve bridges will have to be replaced in
this upstream reach. A list of these bridges follows:
Trenton Avenue, Orchard Street, Trotters Lane, North
Avenue, South Broad Street, Rahway Avenue, Murray Street,
West Jersey Street, West Grand Street, Morris Avenue,
Westfield Avenue, and the Pennsylvania Railroad.
The County will have to reimburse the Corps of Engineers for the
cost of the eleven vehicular bridges, estimated to cost $1,600,000.
These bridges will be constructed during the next five years and State
aid might be made available for this work as in the case of the three
downstream bridges. - 117 - ELSON T. KILLAM AS SOCIATES, INC.
CITY OF ELIZABETH
Extensive improvements have been proposed by the City of Elizabeth
for their storm water collection system. The program for construction
and efficient operation of the storm water collection system is depen
dent to a great degree upon the prior construction of the proposed
Elizabeth River improvement facilities. Elizabeth is generally served
by a combined sewer system. Under conditions of heavy rainfall, many
of the combined sewers cannot handle the storm flows. This results
in the combined storm runoff and sanitary sewage backing up into base
ments and ponding in the streets. Under extremely heavy storms, the
main interceptor sewer capacity is exceeded and the combined sewage
overflows into the Elizabeth River. These conditions create an unde
sirable condition in the densely populated area of the City. The con
struction of a separate storm sewer system as proposed for the City
of Elizabeth will eliminate a great part of this flooding.
TABLE XXI CITY OF ELIZABETH 5 LOCAL DRAINAGE IMPROVEMENTS
Item Cost
Improvements to eliminate frequent flooding
Stage I, 1963-1981 (partially complete) $12,371,000 Stage 2 12,606,000
Improvements to eliminate municipal pollution in the Elizabeth River, the Meadowlands and Arthur Kill:
Stage 3 7,752,000 Stage 4 1,450.000
Total Construction Cost $34,179,000 Administration, Financing, and Engineering Expenses at 15% 5,127.000 Total Cost $39,306,000* - 118 - ET.SON T. KILLAM AS SOCIATES , INC.
Work under Stage 1 will relieve many areas that are now frequently
flooded in the City during storms with a five-year return frequency.
The program will also relieve overloading of the westerly interceptor
by diverting sanitary sewage to the Joint Meeting Trunk Sewer.
Work in Stage 2 will relieve remaining areas that are now flooded
frequently due to inadequate storm drains and eliminate flooding of
the streets at locations served by combined sewage.
Stage 3 includes work necessary to separate the sanitary sewers
and storm drainage system in the City and to eliminate pollution from
combined storm sewer overflows into the Elizabeth River and the Meadows'
ditches.
Stage 4 provides for the separation of sanitary and storm sewers
in the area of the City where combined sewers now overflow into the
Arthur Kill.
The scheduling of this work has been based upon need and the avail
ability of funds. The immediate plan, Stage 1, and the long-term plan
for improvement are shown on Exhibit XVII.
The construction of the Elizabeth River improvements is necessary
to provide a proper outlet for the proposed storm water collection
svstem.
- 119 - ELSON T. KILLAM ASSOCIATES, INC.
The U. S. Army Corps of Engineers has determined that it is not
justified to make major channel improvements upstream of the Ursino
Detention Basin. The flooding of developed land in that reach is
limited to only a few locations. This can be attributed to the fact that
the flood plain north of Ursino Dam is the property of the Union County
Park Commission. A great deal of this land was donated by the Township
of Union, which purchased it from private owners in the 1930's. The
Township of Union reports that only one limited area is subject to
flooding which can be attributed to the Elizabeth River.
TOWNSHIP OF HILLSIDE
The Township of Hillside has experienced flooding at two locations
which has been attributed in part to the Elizabeth River. The first
area of flooding extends along Central and Baker Streets from Conant
Street to Second Street. The flooding is reported to be one to three
feet deep during heavy rainfalls. The southern end of Central Avenue
and Conant Streets are below elevation 30'. The elevation of the crest
of Ursino Dam is 22.4' and is located approximately one mile downstream.
The water surface immediately upstream of the dam at design storm flow of
5,900 cfs is approximately 26.4', which results in only about 3.6 feet
of differential in elevation in this reach of the river. In addition,
the river channel in this reach is of limited capacity.
The flooding problem along Central Avenue is aggravated by an existing storm drain which is located in Central Avenue. The backwater from the
river surcharges this conduit causing it to overflow into the streets in
the lower areas. If the surcharge could be eliminated, the storm sewer would be of adequate capacity for all but the most severe storms.
- 120 - ELSON T. KILLAM AS SOCIATE S, INC.
A detailed field investigation including surveys of existing facilties
including channel sections and hydraulic analysis of the Elizabeth
River from the Ursino Dam to the Lehigh Valley Railroad bridge will be
required to determine whether the flooding at this location can be
economically justified and the extent of improvements required.
The second area of extensive flooding is located in the Yale and
Harvard Street area just south of Route 22. The area is fairly low and
two large storm sewers pass through this section. It appears that a
combination of high stage in the Elizabeth River combined with periods
of high local storm water runoff causes the flooding in this area. The
water surface in this portion of the river is partially controlled by
Salem Pond Dam, at analysis Location E9. A detailed field investigation
and hydraulic analysis should be made of both the Salem Pond Dam and
Ursino Dam to determine their effect upon the stream. These structures
are of limited benefit as detention basins and may be major factors in
creating the flooding problems. A study is warranted to determine whether
the removal of these structures is warranted.
TOWNSHIP OF UNION
The Township of Union is drained by both the Elizabeth and Rahway
Rivers. Most of the land area is sufficiently high and is not subjected
to flooding from these streams, and much of the land adjacent to the
streams has been developed as parks. Eight of the parks have been
utilized to serve as detention basins during periods of heavy rainfall.
This arrangement in the Township of Union is the most extensive and ef
fective use of detention basins for storm water retention in the County.
- 121 - ELSON T. KILLAM AS SOCIATES, INC.
The storm drainage facilities in the Township are reported to be
generally adequate with flooding reportedly occurring with frequency in
only one limited area. Some concern has been expressed over potential
flooding at the Route 82, Morris Avenue Bridge, over uhe Rahway River.
The Morris Avenue Bridge is reported to be the cause of substantial
ponding upstream of this crossing in both Union and Springfield. It is
recommended that planning for the replacement of this bridge be considered
by the State Depatement of Transportation.
Another flood area is located near the intersection of Morris Avenue
and North Avenue. Branch 8-2 of the Elizabeth River flows out of Union
into the Newark State College property and then into a culvert in
Trotters Lane, Elizabeth, to a point of discharge downstream of the
Ursino Lake Dam. The existing culvert is totally inadequate and is the
primary cause of the extensive flooding in the area. The replacement of
this culvert should be considered and it may require the cooperation of
the County in implementing the plan.
A review of the drainage structures at the analysis location within
the Township of Union reveals that of the eight bridge structures in the
Elizabeth watershed, five have been rated as generally of inadequate
capacity for peak storm flows and three marginal. However, no major
flooding has been reported at any of these locations. This may be at
tributed to the reduction of the storm flows by the retention basins along
tin.' river and resultant lowered rates of runoff. Since serious flooding
I.as not been reported at any of these structures, it is recommended that
consideration of replacement be given a low priority.
- 122 - EI.SON T. KILLAM ASSOCIATES, INC.
MORSES CREEK WATERSHED
The City of Linden has plans for an extensive program of storm
drainage improvement and some of this work has already been undertaken.
The program includes plans for both stream channel improvement and en
largement of relief storm sewer facilities. Morses Creek, and its
tributaries West Brook and Peach Orchard Brook, have been subjected to
extensive flooding for many years.
A comprehensive storm drainage improvement plan has been prepared for
the City of Linden and is outlined in a report entitled "Sewerage,
Drainage and Flood Control Improvement Program . The report outlines a
program which will require the expenditure of $11,000,000 to resolve the
sanitary sewerage and storm drainage problems ol the City. It has been
estimated that escalation of costs due to inflation v«ill require the
expenditure of $16,000,000 under present day condiLi, is.
A portion of the storm drainage improvements recommended have been
started. Three of the storm drainage projects are under construction
and a fourth is in the design stage. The total cost of these four storm
drainage projects is approximately $1,700,000. A Federal Grant of
$399,000 has been made available for this work.
The recommended work for West Brook, Peach Orchard Brook and Morses
'reek has not been undertaken. The cost for these stream improvements
T; estimated in the November of 1967 report is shown below.
- 123 - ELSON T. KILLAM ASSOCIATES, INC.
Peach Orchard Brook $1,300,000 West Brook 3,000,000 Morses Creek 1,400,000 Pumping Station 100,000
TOTAL $5,800,000
Administration, Financing Engineering, Legal $1,160,000
TOTAL $6,960,000
It has more recently been estimated that the West Brook channel im
provement will cost a total of $3,800,000, of which $2,700,000 will be
required to reconstruct 16 bridges which cross this stream. Three of
these bridges cross State Highways and would be replaced by the State
Department of Transportation. One culvert passes under the Pennsylvania
Railroad tracks and the remaining twelve bridges or culverts pass under
City streets, and the reconstruction of these bridges and culverts will
be the responsibility of both the City of Linden and the Union County
Highway Department. A West Brook - Bridges Required To Be Replaced
Saint George Avenue (State) Gibbons Street Curtis Street Elm Street Knopf Street Brook Street (South of Knopf Street) Lumber Street Elizabeth Avenue (State) Pennsylvania Railroad Linden Avenue Morris Avenue Munsell Avenue W. Stimpson Edgar Road (State) llth Street Winans Avenue
In order to eliminate flooding along Peach Orchard Brook, it will be
necessary to replace several bridges, two of which are considered to be - 124 - ELSON T. KILLAM ASSOCIATES, INC.
the State Department of Transportation's responsibility. A list of
these bridges follows.
Peach Orchard Brook - Bridges Required To Be Replaced^
Dill Avenue Bergen Avenue Cranford Avenue Essex Avenue Elizabeth Avenue (State) Pennsylvania Avenue Pennsylvania Railroad Linden Avenue Edgar Road (State)
As in the case of West Brook, it has been estimated that reconstruc
tion of the bridges will require a major portion of the estimated ex
penditure of $1,300,000 required to be spent to eliminate flooding along
Peach Orchard Brook.
The report has also called for the widening and reconstruction of
the channel, and several small dams downstream of the confluences of
Peach Orchard Brook and West Brook. The Esso Company has constructed
several low dams in their property, maximum elevation +6', to store
water for cooling purposes. Several of the existing dams are reported
to have insufficient spillway capacity to pass large storm flows. 4 The storm drainage report for the City of Linden recommends the
widening or elimination of these structures combined with improved
channel sections to a point just upstream of the South Shore Branch of
the Central Railroad of New Jersey. The construction cost for these improvements was estimated to be $1,400,000 (in 1967). . It has been
estimated the project construction cost would exceed $1,900,000 under
present day prices.
- 125 - ELSON T. KILLAM AS SOCIATES, INC.
The tidal protection program recommended for Morses Creek, as
described in Chapter IX, would not eliminate the necessity for the
channel work improvement on Morses Creek. If the channel were not im
proved, the inadequate channel capacity would result in flooding of land
adjacent to the Creek. The recommended stream channel improvement will
reduce the frequency of flooding caused by storm water runoff when the
tide levels are below elevation +6'. However, to obtain protection from
tidal inundation due to tides higher than a one or two-year frequency,
tide gates and a storm water pumping station will be required to prevent
flooding from surcharge and backwater caused by high tides.
BOROUGH OF ROSELLE
The Borough of Roselle lies within the Morses Croek watershed, with
both West Brook and Peach Orchard Brook passing through the Borough.
.here are two areas along West Brook that experience Hooding.
The first area is located in the reach of the stream extending from
St.George Avenue to Raritan Road. The Borough of Roselle has recently
deepened and widened the portion of this channel from St. George Avenue
to Brooklawn Avenue. It has been reported that flooding still occurs in
this area despite the channel improvement and this flooding is attributed
to the inadequate culvert capacity at St. George Avenue and the inade
quate downstream channel capacity. As previously discussed, the City of
Linden is planning to improve this downstream channel as part of its
long-range improvement program. However, the replacement of the St.
George Avenue culvert by the State Department of Transporation will also
be required to completely eliminate flooding in this area of Roselle.
- 126 - ELSON T. KILLAM ASSOCIATES, INC.
The flooding between Brooklawn Avenue and Earitan Road, along
Shaffer Avenue and Clark Street, is believed to be caused by a combination
of inadequate channel sections and local storm sewer facilities.
The second area of flooding occurs in the drainage area of Branch
9-1-7, above Analysis Location M-3. Wide-spread local flooding occurs
as a result of the inadequate stream enclosure and inadequate local
storm sewer collection facilities. Flooding along this stream is also
reported to be severe immediately upstream in the Borough of Roselle
Park. Inter-municipal cooperation with County assistance may be re
quired to correct these flooding conditions.
Flooding also occurs in the Borough of Roselle along Peach Orchard
Brook. The most severe flooding occurs from St. George Avenue, Analysis
Location M-7, to Columbus Avenue about six blocks to the west. The
stream has been enclosed in a box culvert, downstream in Linden, which
has insufficient capacity. Several bridges between St. George Avenue
and Columbus Avenue have inadequate capacity and require enlargement.
The improvement to the reach of the stream in Roselle would be of limited
benefit unless additional capacity is also provided downstream in the
City of Linden. Only minor flooding has been reported in the City of Linden along
this reach of the stream, and the City does not plan for improvements in
this reach of Peach Orchard Brook. In general, County participation may be required to implement a
comprehensive plan to eliminate this flooding problem.
- 127 - ELSON T. KILLAM ASSOCIATES, INC.
BOROUGH OF ROSELLE PARK.
The Borough of Roselle Park is also drained primarily by Morses Creek
with the remainder of the land area draining into the Elizabeth River or
its tributaries. Severe flooding has been reported at three locations
for many years in the Borough.
The first area of flooding is at Analysis Location M-l, on West
Brook. The flooding is reported to occur more than once a year with
flooding depths of two feet. The flooding is caused by a combination of
inadequate channel capacity and an inadequate culvert crossing under the
Central Railroad of New Jersey. A similar condition also exists at the
Railroad crossing of Stream 9-1-7. The Borough has requested both State
and Federal assistance to eliminate this flooding condition. The State
has recommended that the Borough prepare plans for the required improve
ment of the channel for submission to the Division of Water Resources
for approval. It has been reported that such studies and plans are re
quired by the State to demonstrate the extent of the inadequacy of the
Railroad culvert and the downstream channel and the proposed improvements
required to provide relief from flooding. The Borough is presently
engaged in a master storm drainage study which will result in the prepara
tion of plans to meet the State's requirements after which a program of
implementation will be developed.
The third area in Roselle Park that is frequently flooded includes
Dalton, Camden, Berwyn and Avon Street area immediately north of West-
field Avenue. This area is tributary to the Elizabeth River discharging
into the City of Elizabeth. It has been reported that inadequate conduit
capacity in Elizabeth is primarily responsible for the flooding in this
- 128 - ELSON T. KILLAM ASSOCIATES, INC.
area. The master drainage plan for the City of Elizabeth calls for
the installation of a relief storm sewer in this area which will then
make it possible for the Borough of Roselle Park to provide adequate
storm drainage facilities for this area.
BOROUGH OF KENILWORTH
Flooding has also been reported along West Brook in the Borough of
Kenilworth. In the report outlining a "Drainage and Flood Control
-I n Improvement Program" prepared for the Borough, it has been recommended
that the West Brook channel be improved to eliminate the flooding. The
preliminary report calls for the construction of a vertical wall, re
inforced concrete channel with an invert elevation about two to four
feet lower than the existing grade. The construction of a channel with
a lower invert will also require some stream work improvement downstream
in Roselle Park.
The County may be required to assist in coordinating the construction
of improvements along West Brook. Four communities have undertaken
planning for improvements to this stream. To obtain maximum benefits
at minimum cost, a coordinated effort between Kenilworth, Roselle Park,
Roselle, Linden, the Union County Engineering Department and the State
of New Jersey Department of Transportation will be required.
- 129 - •> M& LS £>jfV '-Pi 1 iiiF% tf™' f-,£
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TYPICAL TYPICAL FLOOD WALL SECTION
UNION COUNTY PLANNING BOARD EXHIBIT SOURCE:U.S. ARMY CORPS OF ENGINEERS ELSON T. KI:L:LAM ASSOCIATES,INC.
XI. PARKLAND AND FLOOD PLAIN MANAGEMENT
Union County is the second most-densely populated County in the
State of New Jersey. The County maintains an extensive park system
of 5,200 acres or 7.85 percent of the total County area.
A great deal of foresight and planning has gone into the development
of County park lands. With the exception of the Watchung Reservation,
the parks have generally been located in the flood plains and low lying
areas along the major streams.
Exhibit XIX shows the locations of the existing park lands and
proposed parks throughout the County. It is quite obvious that extensive
additions and improvements are proposed throughout the County, and much
of the land is being acquired. The parks along these streams serve several
important functions as outlined below:
1. The park lands provide for open space for recreation.
2. They serve as flood plains to help pass severe storm flows.
3. They eliminate the possibility of flood plain encroachment by buildings and structures.
4. Park lands can be effectively used as detention basins to reduce peak storm flows.
5. Rights-of-way are provided for required stream improvements.
In summary, the location of park lands and recreation areas in the
flood plains and low-lying areas adjacent to streams results in the
most desirable use of what would normally be very marginal lands for
development. The prospect of intermittent flooding generally prohibits
the satisfactory development of residential, commercial or industrial
development. Filling of the flood plain, for the purpose of development,
generally restricts the normal flow or storm water runoff and flow
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causing more intense flooding and increases the possibility of property
damage. During periods of heavy rainfalls, the flooding of the low-lying park
lands causes negligible and intermittent interruption of use and may
create only a minor problem of clean up after the flood levels recede.
Table XXII shows the existing and proposed County and municipal
parks by watershed and by name that serve a dual role of providing
recreation as well as natural flood plain facilities. A detailed descrip
tion of each of these facilities has been presented in Chapter X under
each watershed.
The Union County Park Commission has effected an outstanding program
of flood plain management along many streams where this has been possible.
Not many other counties in the State have been able to provide as ex
tensive a system of flood-plain park lands. An ambitious program is
also being undertaken to acquire additional lands which generally are
located adjacent the streams of the County. The priority of land
acquisition on the basis of need for flood plain management is also
shown on Table XXII. These recommendations generally conform to Park
Commission objectives. The analysis of the drainage ways in this report
has established the desirability of three additional park lands not
presently being considered for acquisition by the Park Commission.
They are the Cedar Brook Tract 19, Robinson's Branch Parkway and South Branch Parkway. The possible addition of these lands to the County
Park system has been discussed with representatives of the Park Commission
and basic agreement with the desirability of acquiring these lands was
indicated.
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TABLE XXII
FLOOD PLAIN MANAGEMENT PROGRAMS
Recommend Acquisition Existing Proposed Prior To
GREEN BROOK
1. Green Brook Park 1. Green Brook Parkway 1980 2. Watchung Reservation
CEDAR BROOK
3. Cedar Brook Park 2. Tract 19 Park and 1980 Detention Basin
ELIZABETH RIVER
4. Elizabeth River Parkway north of Ursino Dam
5. Mattano and Sheridan Parks
6. Galloping Hill Park-West Branch of Elizabeth River
7. Township of Union Parks and Detention Basins
MORSES CREEK
8. Wheeler Park
PASSAIC RIVER
9. Passaic River Parkway 3. Passaic River Parkway 1990 Additions
4. Millington Detention Basin 1990 by U.S.A.C.E. Morris Co.
RAHWAY RIVER
10. Rahway River Parkway 5. Robinson's Branch Parkway 1980 City of Rahway
11. Black Brook Parkway 6. South Branch Parkway 1980 City of Rahway
12. Lenape Park 7. Kings Creek Park 1990 (Linden Park) - 132 - ELSON T. KILLAM ASSOCIATES, INC.
Recommend Acquisition Existing Proposed Prior To
RAHWAY RIVER (Continued)
13. Nomahegan Park 8. Ash Brook Detention 1980 Basin
14. Echo Lake Park
15. Milton Lake Park
16. Ash Brook Swamp Reservation
17. Tamaques Reservation (Westfield)
18. Netherwood Detention Basin (Plainfield)
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XII. PROGRAM STAGING AND COST SUMMARY
The storm drainage and flood control projects that have been dis
cussed in this report fall into two general classifications:
1. Improvements to streams or major water courses and channels
generally affecting several communities, and
2. Local improvements which affect no more than two communities.
Improvements to stream channels and major water courses have been
stressed in this report because such improvements generally provide the
greatest benefits, affect the greatest population, eliminate the most
serious damage, and require the difficult coordination and funding
by governmental agencies above the local municipal levels to implement
the plan. The establishment of priorities for these projects is re
quired so that available Federal, State, and County funds can be allocated
to the programs which will provide the greatest benefit.
Table XXIII lists the recommended improvements for the major water
streams in Union County in an order of priority predicated upon need
and estimated overall benefits to be derived. The estimated 1971 con
struction cost of each project is also shown. Where detailed plans or
studies have been prepared, the cost estimates have been updated and
shown to reflect present-day costs. A detailed description of each
project has been presented by Chapter X, under each watershed.
Extensive flooding and damage is recognized to occur along each
of these streams. It would be desirable to endeavor to establish a
reasonable timetable for undertaking these projects at least in part
in a first-stage program possibly not later than 1980. The Elizabeth
River Project, scheduled to be completed in 1976, will require a
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5-year construction period. The design has been completed, and funds
have been committed for this project. None of the other projects have
been carried beyond the preliminary design stage and no funds have been
allocated for their construction.
TABLE XXIII
PRIORITY AND ESTIMATED COST OF IMPROVEMENTS FOR MAJOR WATER COURSES IN UNION COUNTY. NEW JERSEY
Estimated 1971 Construction Priority Project Cost
1. Elizabeth River, Front St. to Ursino Dam $20,000,000.00
2. Green Brook, West End Ave. to Union Ave. 6,139,000.00
3. Morses Creek Stream Improvement, Linden 8,200,000.00
4. Rahway River, Springfield through Cranford 5,550,000.00
5. Newark Meadows Pump Station 2,800,000.00
6. Cedar Brook Tract 19, Detention Basin 1,000,000.00
7. Robinson's Branch, City of Rahway to Scotch Plains 1,900,000.00
8. Passaic River Bridge Replacement 3,600,000.00
9. Morses Creek Tidal Flooding Prevention Program 4,400,000.00
In general, the implementation of a major storm drainage improvement
plan where several municipalities are involved including the complex rami
fications of establishing an agency to plan and undertake the work, the
funding and sharing of costs, and the obtainment of easements or rights-
of-way takes considerable time. A prime example of this difficulty is
exemplified by the fact that the U. S. Army Corps of Engineers has been
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trying since 1939 to implement a "favorable report on a flood protection 2 plan for the Passaic River" . This vast, complex and costly improvement,
including the upper Passaic River channel improvement, has still not
been accepted when the design can proceed.
An attempt should be made to undertake the construction of projects
1 through 5 as shown on Table XXIII, prior to 1980. The County policy
has been to limit its financial assistance to bridges and culverts at
major stream crossings of municipal and county roads. Table XXIV has
been prepared to show the bridges which will require replacement or en
largement for the major stream improvements. The table shows the cost
for each project which includes County bridges, State highway bridges
and railroad bridges which do not have adequate capacity. State aid
of up to 50% is available for County bridge construction. The funding
for the reconstruction of these bridges should be budgeted by the County,
as has been the practice in the past, to coincide with the scheduled
construction of the stream improvements.
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TABLE XXIV
BRIDGES REQUIRING REPLACEMENT FOR IMPROVEMENT OF MAJOR WATER COURSES
ELIZABETH RIVER - Cost of Bridges. $1.600.000.00
Trenton Avenue, Orchard Street, Trotters Lane, North Avenue (State), South Broad Street, Rahway Avenue, Murray Street, West Jersey Street, West Grand Street, Morris Avenue (State), Westfield Avenue (State), and the Pennsyl vania Railroad.
GREEN BROOK - Cost of Bridges. $800.000.00
Jefferson Avenue, Rock Avenue, Sycamore Avenue, Netherwood Avenue, Rayiaond Avenue, Union Avenue.
MORSES CREEK - Cost of Bridges. $4,000,000.00
City of Linden - West Brook
St. George Avenue (State), Gibbons Street, Curtis Street, Elm Street, Knopf Street, Brook Street (South of Knopf Street), Lumber Street, Elizabeth Avenue (State), Pennsylvania Railroad, Linden Avenue, Morris Avenue, Munsell Avenue, W. Stimpson, Edgar Road (State), llth Street, Winans Avenue.
City of Linden - Peach Orchard Brook
Dill Avenue, Bergen Avenue, Cranford Avenue, Essex Avenue, Elizabeth Avenue (State), Pennsylvania Avenue, Pennsylvania Railroad, Linden Avenue, Edgar Road (State).
RAHWAY RIVER. Springfield through Cranford Cost of Bridges - $600,000.00
Morris Avenue (State), East Bound Rt. 22 (State).
PASSAIC RIVER - Cost of Bridges. $3.600.000.00
Route 24, Chatham Road, River Road, Stanley Avenue, Mt. Vernon Avenue, Passaic Street, Central Avenue, Snyder Avenue, Springfield Avenue, 2 Erie Lackawanna Railroad Bridges.
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Local storm drainage improvements have generally been financed by the
individual municipalities. County assistance has generally been provided
for bridges or culverts at road crossings and, in some cases,
Federal funds have also been made available for some municipal projects.
Where improvements are required in contiguous communities, planning and
construction should be undertaken concurrently whenever practical to
obtain maximum benefits.
Table XXV shows those municipalities in the County who are presently
considering or undertaking the construction of storm drainage improvements,
generally in accordance with a long-range master plan. As municipal funds
become available, phases of these improvements may be undertaken under a
stage program of construction.
The construction timetable for these municipal projects range from
five years to over twenty years.
Most municipalities advise the County as to their proposed construc
tion timetable so that County bridge and culverts can be scheduled to conform with municipal planning.
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TABLE XXV
COST ESTIMATE FOR MAJOR LOCAL IMPROVEMENTS
Estimated 1971 Municipality and Description Cost of Total Master Plan Of Top Priority Project Including Priority Projects
CITY OF ELIZABETH, Stage 1 Local Improvements & Eliminate Combined Sewers $58,500,000.00
CITY OF LINDEN Local Improvements 4,630,000.00
SPRINGFIELD, Bryants Brook, Van Winkles Brook, Local Improvements 1,130,000.00
SCOTCH PLAINS, East Branch Green Brook, Winding Brook and Local Improvements 2,500,000.00
CLARK TOWNSHIP, Pumpkin Patch Brook and Local Improvements 1,060,000.00
NEW PROVIDENCE, Salt Brook, and Local Improvements 1,240,000.00
CITY OF RAHWAY Local Improvements and Eliminate Combined Sewers 640,000.00
BERKELEY HEIGHTS,Local Improvements
MOUNTAINSIDE,Local Improvements 900,000.00
KENILWORTH,Local Improvements 2,450,000.00
FANWOOD, Local Improvrments 523,000.00
PLAINFIELD, Eliminate Flooding and Central Railroad of New Jersey Underpasses
ROSELLE PARK, West Brook and Local Improvements
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XIII. IMPLEMENTATION AND FINANCING DRAINAGE IMPROVEMENTS
The implementation of a major storm drainage improvement—
whether undertaken by a single community within its own boundaries or
whether undertaken by more than one community to resolve an intermunici-
pal drainage problem—is often difficult to accomplish because of the
high cost and the difficulty of demonstrating equivalent cost benefits.
MUNICIPAL PROGRAMS
Where a municipality has a drainage problem in which improve
ments to streams or channels are required, or where extensive piping is
undertaken to eliminate flooding in local areas, it has been the prac
tice in the past to undertake this work under a general improvement
ordinance which, in effect, provides for the cost to be paid through
general taxation.
Some communities have attempted to finance drainage improve
ments by considering local assessments. This comprises the assessment
of a portion or all of the storm improvement cost against benefiting
properties. The difficulties and problems involved in equitably assess
ing the cost of storm drainage improvements have resulted in complica
tions and delays in financing and oftentimes costly litigation in those
communities that have attempted to assess storm drainage improvements.
Few communities consider the assessment of storm drainage improvements
to local benefiting property owners to be practical.
Because drainage improvement costs are relatively high, it is
not always possible to undertake the entire project at one time. As a
result, improvements are generally undertaken in stages, beginning in
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those areas where conditions are most severe. It is often found that
improvement cost and available funds also comprise a signi ficant factor in establishing priorities for storm water improvements.
The County becomes involved in participating in local drain
age improvements by a municipality even when the improvements are recog
nized to serve only a limited area of a community. The County is gen
erally called upon to undertake improvements at major bridge crossings
or culverts passing under County roads or municipal streets. It is
customary for the County to undertake this portion of the work directly,
including design and direction of construction and the community is thus relieved of the responsibility of making the improvements required for the
the replacement of bridge or culvert crossings. In other cases where a
community undertakes a comprehensive drainage improvement plan which
may involve pipe crossings of streets, the County oftentimes enters
into an arrangement with the municipality to compensate for the cost of
the improvements undertaken at street crossings. Such reimbursement by
the County is in consideration of relieving the County from the respon
sibility of constructing these facilities and for providing future
maintenance of the improvements. This also affords a uniformity of
design which results in the most efficient and effective improvement.
Where such arrangements are made, the County Engineering De
partment generally reviews the plans of the stream or channel improve
ments and makes recommendation for participation by the County for the enlargements or improvements required to the culvert or bridge crossings
under roads. Generally speaking, both the municipalities and the County
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have found this arrangement to be mutually advantageous, and it is our
recommendation that this practice of County participation in local muni
cipal storm drainage improvements be continued. Because of the magnitude
of the work required for local storm drainage improvements, it is sug
gested that an order of priority be established within each community,
combined with a timetable so that the necessary funds can be budgeted
annually both by the County and the communities for undertaking such
work.
Based on the foregoing, we would recommend that consideration
be given in the future to a continuation of County support of municipal
drainage improvements to the extent that municipal projects will not be
delayed or impaired because of the inadequacy of County bridge and cul
vert structures.
It is recognized that many of the municipalities in the County
have undertaken either preliminary studies or preliminary plans which
set forth long-range objectives for improvements required to substantially
eliminate local flooding. Where municipalities have completed such
studies, a program of implementation has generally been started, with
progress dependent upon the availability of funds.
Where municipalities have not undertaken a comprehensive
study, it is recommended that these municipalities consider such action with the view toward determining the detailed scope of work required,
preliminary estimates of cost, and those improvements that can be under taken on a local basis with nominal cost as contrasted to those major
improvements which should be coordinated with adjoining municipalities.
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A comprehensive municipal storm drainage report and prelimin
ary plans will assist each community in establishing a schedule of
priorities and providing for funding over a long-term period with the
view toward eventual completion of all of the major storm drainage
improvements required.
The distribution of all available information between the
various levels of municipal and County government will be the first
action required to ensure the efficient and effective operation of
Union County Planning Board and to accomplish the objectives set forth
in this County Storm Drainage and Flood Control Master Plan.
INTERMUNICIPAL PROGRAMS
Many examples have been cited in this report where streams
and channels pass through several municipalities and improvements are
required in more than one municipality. Unless the municipalities can
be brought together in a coordinated joint effort, both from the stand
point of design and construction, the benefits of the improvements
made by an individual municipality may be minimal, and in some cases
may even be detrimental. Unless there is complete cooperation between
the municipalities and unless the improvements are undertaken in a logi
cal order of priority, funds might be expended without realizing the
total benefits possible. Generally, it is necessary to start improve ments at the downstream end of a channel or stream with the work pro
gressing upstream in order to provide effective and permanent improve
ments. Thus oftentimes an upstream municipality is dependent upon
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The County may have to serve as the coordinating agency for
intermunicipal storm drainage improvements. Such a policy is warranted,
since the County does participate in controlling aspects of drainage
improvements, including the enlargement of bridges and culverts under
highways, as well as participating in the cost of road culvert improve
ments undertaken by municipalities. The County would be in a position
to ensure that a bridge replacement or enlargement for a municipality
will conform to an overall stream improvement program and that the con
struction schedule and scope of work proposed by the municipality will
complement the bridge reconstruction. Under this concept of County par
ticipation with control, a community will not have the advantage of
County participation in a bridge improvement unless assurances are
provided that the required stream improvement work will also be under
taken to effect a total benefit. Where a downstream community may be
affected, the communities would be brought together for joint discus
sions which would be designed to promote joint participation so as to
provide coordinated efforts between municipalities.
In Union County, the value of storm drainage projects under
consideration has been estimated to cost $125,000,000. The implemen
tation of such a costly program will require considerable planning and
coordination.
Even though 60 percent of these programs have been proposed
by individual municipalities, many of the improvements will affect or
are dependent upon the coordinated action of other municipalities. In
the past, the coordination of intermunicipal storm drainage improvements
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has not always been successful. Without recognition and attention to
the upstream and downstream factors, which may control, inadequate facil
ities often result. Thus the importance of the County in coordinating
the design and construction of drainage facilities is obvious.
County action in coordinating planning activities of storm
drainage improvements passing through several municipalities should
result in more effective, more economical and more timely development
of needed improvements to eliminate flooding.
Where the drainage area exceeds 640 acres (a square mile), it
is required that plans and specifications of proposed improvements be
submitted to the New Jersey Division of Water Resources to obtain ap
proval of plans and for the issuance of a permit for construction. A
state Agency, in effect, approves the design basis which assures the
adequacy of the carrying capacity of facilities proposed.
A "uniformity of design" has been recommended in this report.
The design basis as set forth in the various watersheds in Union County
will become the basis for approval of detailed plans and specifications
submitted to the Division of Water Resources after the County Master
Plan for storm drainage improvements has been adopted.
The Division of Water Resources is not in a position to pro
vide the required coordination of design and construction activities
between the various municipalities, and it would appear that this would
be the logical responsibility of a County agency. The County Planning
Board should be the agency who would be responsible for coordinating
the efforts of the municipalities in major intermunicipal drainage im- - 145 - ELSON T. KILLAM AS SOCIATES, INC.
provements. It is suggested that the Division of Water Resources advise
the County Planning Board whenever drainage plans are submitted for
approval. This would afford the County a means of coordinating inter-
municipal work and providing a method of communications between the
State and the municipalities of the County and to assist in the imple
mentation of the proposed improvements.
MAJOR WATER COURSE PROJECTS
When these improvements are beyond the capabilities and con
trol of any given community, the Corps of Engineers are often called
upon to undertake the detailed studies and assist in the financing of
the improvements. Where the Corps of Engineers are able to undertake
these major studies, an effective coordinating agency is available for
the communities and a program can often be developed which will be of
permanent value at modest cost. Where the studies and improvements
cannot be justified by the Corps of Engineers, the municipalities must
undertake the planning and financing of the works alone, if a proper
solution is to be developed.
The recommended improvements for the major water courses
total approximately $52,000,000. The construction of many of these
projects has been proposed by the U. S. Army Corps of Engineers. However, dependence upon the U. S. Army Corps of Engineers
to expedite all of these projects is not realistic. The Corps is
dependent upon the U. S. Congress for approval and funding of projects, and such a concentrated effort in one County is unlikely.
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The Elizabeth River Project will be the first major river
improvement program by the U. S. Army Corps of Engineers in the State
of New Jersey. It would be optimistic to assume that more than one
or two of the other major improvements required would be undertaken in
the near future. In 1963, the Corps completed a study of the entire
Rahway River and reported that improvements were not economically
justifiable by their standards, with the exception of a reach in the
City of Rahway.and South Orange (Essex County). It has been reported
that a restudy of certain reaches of the river may soon be undertaken by the Corps. An investigation is also being conducted by the Corps of
the Green Brook Watershed. Both investigations are cost-benefit
analyses to determine whether improvements can be justified.
In summary, the U. S. Army Corps of Engineers is committed
to the improvement of the Elizabeth River and is reportedly studying
the Passaic River, Green Brook, and the Springfield-Cranford reach of
the Rahway River. The municipalities of the County should urge the
expediting and completion of these studies along with the recommenda
tions for cost sharing responsibility. The greatest share of the cost
would be absorbed by the Federal Government if the Corps can demonstrate
the economic feasibility and demonstrate the required cost-benefit re
lationships. If the results of the study are such that the Corps can
not justify or undertake the improvements, then the County and munici palities must evaluate the need for the projects and undertake the
improvements. Federal and State aid may also be available if the proj ects are undertaken under local sponsorship.
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The improvements recommended in Table XXIII, which are not
presently under study by the U. S. Army Corps of Engineers, can best
be expedited by the assumption of responsibility by the County or by
a group of interested municipalities. The Union County Engineering
Department has limited its storm drainage improvements to bridges and
culverts under major thoroughfares and for local drainage facilities
passing under County and municipal roads.
An active drainage committee is presently being formed by
the municipalities bordering Green Brook in Union, Middlesex, and
Somerset Counties. This is the first such group of municipalities being
formed in the State for the purpose of flood control. Enabling legi
slation for this group of municipalities or drainage authority to func
tion is presently being considered by the New Jersey Legislature. The
formation of such drainage Authorities is an effective method of imple
menting regional drainage project. Even if the Corps of Engineers
undertakes the required improvement to Green Brook, an authority will
be necessary to provide the required maintenance. In summary, if the extensive storm drainage improvements
required within Union County are to be undertaken in an efficient and
effective manner, the County will have to assume greater participation
than hereinbefore. The County may also be required to provide increased funds to participate effectively in regional drainage projects. Such
County action would be in conformance with the recommendations of the report upon "Surface Water Control in New Jersey" 13 prepared by
Stephen A. Decter. This report was prepared for the State and analyzed
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the existing organization, laws, and policies of all levels of govern
ment concerning drainage and flood control. The report suggested the
reorganization and increased participation by State and County Govern
ments in flood control work. The recent formation of the State of
New Jersey Department of Environmental Protection was based upon the
"Decter" report. Additional changes at the State level may be expected
to occur in the future, as relates to drainage and flood control pro
grams .
The Union County Planning Board can provide an invaluable
service to the municipalities by coordinating the extensive drainage
programs under consideration. The integration of the various municipal
State and Federal projects into a coordinated effort by the County would
be a major and responsible undertaking.
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APPENDIX A METHODS OF COMPUTING DESIGN FLOWS
The most commonly used method of computing design flows
for drainage facilities in small watersheds is the "Rational
Method." This method was first introduced in 1889 and is
based on the Rational Formula:
Q = C x I x A
Q = Peak Runoff in Cubic Feet Per Second
C = Runoff Coefficient (Refer to Table III)
I = Rainfall Intensity in Inches Per Hour
A = Area of Tributary Watershed in Acres
The overall runoff coefficient C is determined by taking
the weighted average of the coefficients of each tract of a
particular land use. The Area A is the total tributary land
area to the point in question. As previously discussed the
rainfall intensity is dependent upon the location, the storm
frequency and the storm duration.
Based on location, the set of curves which should be used
are those for Sandy Hook, New Jersey, as derived by the U. S.
Weather Bureau of the curves derived by the Division of Water
Resources for Essex and Union County. The storm fre
quency should generally be based on those presented in Table
V. The duration of the design storm should generally be based
on the time of concentration of the particular watershed.
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The time of concentration is defined as the time required
for a partical of water, falling at the most distant point of
the watershed, to travel to the point in question. This is
based on the assumption that the maximum runoff rate will occur
at the instant when the entire tributary area begins to con
tribute flow. Thus, using the "Rational Method">only the peak design
flow is determined. It is done by using a rational formula
which has been devised to match generalized field conditions
and by making many simplifying assumptions. This method has
proven quite satisfactory for small watersheds where more
extensive analysis is not justified by the cost of the improve
ment ;
A more refined procedure called the Hydrograph Method has
been developed. The hydrograph not only yields the peak
design flow as does the rational method but also yields the
flow throughout the duration of the storm and the volume of
runoff. There are many variations of the Hydrograph Method,
which have generally been made to best fit local conditions.
A true or real hydrograph shows simultaneously the recorded
rainfall and runoff for a specific location throughout the
duration of the storm. A synthetic hydrograph is developed
by applying either assumed or field determined runoff con
stants to a selected rainfall intensity. True hydrographs
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are commonly used in conjunction with synthetic hydrographs to
determine the characteristics of the watershed. The synthetic
hydrograph is generally the basis of design since often the in
tensity of the design storm is greater than or less than those
that have been recorded. A synthetic hydrograph enables an
Engineer to more fully analyze the many factors that can in
fluence the runoff from a large watershed. This includes the
fact that both the rate of infiltration and surface detention
vary throughout a storm. Since a hydrograph generally shows
the entire duration of the storm, the infiltration and surface
detention can be varied throughout its length. During the
beginning of a storm, infiltration and surface detention will
generally be the greatest. If the maximum intensity of a
storm occurs several hours after the beginning of the rainfall,
both the infiltration and surface detention will be greatly
reduced, thereby increasing the peak flow.
The use of the Hydrograph Method also makes it possible to
more accurately evaluate the effect of a detention basin on
downstream flows. The effect of a detention basin is much the
same as infiltration and surface detention in that peak flows
may be reduced.
A natural detention basin, an example being the Great Swamp in the Passaic Watershed, will retain water in a similar
manner to that of surface detention. The first water there will
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occupy the storage capacity and may have only a limited effect
upon a subsequent peak flow. However, through the proper de
sign of a manmade detention basin, capacity can be saved to
reduce peak flows. A hydrograph is necessary to accurately
evaluate these effects. A sample of a synthetic hydrograph
is shown on Exhibit III. The hyetograph shown on the top of
Exhibit III is used to account for the influence of infiltra
tion and surface detention, generally called losses. This
hydrograph is the reproduction of a storm which occurred Octo
ber 3, 1903, on the Elizabeth River at Westfield Avenue. It
was developed by the U. S. Corps of Engineers in their study
of the Elizabeth Basin.
A third method which is in use is Statistical Analysis of
Recorded Flow Records. For this method to be applicable, many
years of flow records at a particular location are required.
This method should be applied only to watersheds of fairly
stable development as increased density of development will
change the runoff characteristics of the watershed.
There are 6 permanent stream flow recording stations
within Union County. These are listed in Appendix B with
the pertinent information for each. There are sufficient rec
ords at each to make meaningful statistical analysis of mod
erate length. The validity of each of these analysis depends
upon the period of records and the extent of development that
-A4- DISCHARGE IN THOUSAND C.F.S RAINFALL
X -< o o o O 30 u> o T) X
rn x ELSON T. KILLAM AS SOCIATES, INC.
has taken place during that period. On some streams, an ex
ample being Robinson's Branch of the Rahway River, substantial
development has taken place since the beginning of the period
of records. Thus, a true picture of today's conditions is
not obtained. Rather it is a mean between the flows of 30
years ago and today. However, in a watershed such as the
Elizabeth River, relatively little change has occurred during
the period of record and a more realistic evaluation of today's
flows is obtained.
In Summary there are three basic methods used to compute
design flow runoffs.
1. The "Rational Method" which is felt to be applicable
to small watersheds of relatively simple nature.
2. The "Hydrograph Method" which is applicable to larger
watersheds where more extensive analysis is warranted,
3. The "Statistical Analysis" which is applicable to water
sheds where sufficient records are available and where only
minor changes in the watershed will occur in the future.
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APPENDIX B
Gaging Station 1-3795
Passaic River Near Chatham, New Jersey
Location; 150 Ft. downstream from Stanley Avenue Bridge in Chatham. Drainage Area; 100 Sq. Mi. Records Available: February 1903 to December 1911 October 1937 to September 1969 Average Discharge; 39 Years, 159 CFS
Gaging Station 1-3935
Elizabeth River at Elizabeth, New Jersey
Location: 85 Ft. upstream from Westfield Avenue in Eliza beth, New Jersey. Drainage Area; 20.2 Sq. Mi. of which 2.2 Sq. Mi. contributes to a storm sewer which bypasses the station. Records Available; October 1921 to September 1969 Average Discharge; 47 Years, 24.1 CFS
Gaging Station 1-3945
Rahway River Near Springfield, New Jersey
Location; 50 Ft. downstream from bridge on U. S. Highway 22. Drainage Area; 25.5 Sq. Mi. Records Available; July 1938 to September 1969 Average Discharge: 30 Years, 24.9 CFS
Gaging Station 1-3950
Rahway River at Rahway, New Jersey
Location; 100 Ft. upstream from St. Georges Avenue Bridge in Rahway, New Jersey. Drainage Area: 40.9 Sq. Mi. Records Available; July 1908 to April 1915 October 1921 to September 1969 Average Discharge: 47 Years, 43.3 CFS
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Gaging Station 1-3960
Robinson's Branch Rahway River at Rahway, New Jersey
Location; on right bank of Milton Lake, 2,000 Ft.upstream from Madison Avenue in Rahway, New Jersey Drainage Area; 21.6 Sq. Mi. Records Available; September 1939 to September 1969 Average Discharge; 29 Years, 21.9 CFS
Gaging Station 1-4035
Green Brook at Plainfield, New Jersey
Location; 20 Ft. downstream from Sycamore Avenue Bridge in Plainfield, New Jersey Drainage Area; 9.75 Sq. Mi. Records Available: May 1938 to September 1969 Average Discharge; 30 Years, 11.7 CFS
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BIBLIOGRAPHY
(1) "Survey Report for Flood Control - Rahway River, New Jersey." By - U. S. Army Engineer District, New York Corps of Engineers, Serial No. 75 - May 1961.
(2) "Passaic River Basin Water Resources Development Information Bulletin" By - Harvey C. Jones - Robert A. Roe; Issued Jointly by, U. S. Army Engineer District, New York Corps of Engineer, and Department of Conservation and Economic Development, State of New Jersey, December 1968.
(3) "Streams, River Basins and Areas in New York and New Jersey", Elizabeth River Basin Interim Survey Report by U. S. Army Engineer District, New York Corps of Engineers, New York 3, New York, October 1964. Serial No. 84.
(4) "Sewerage, Drainage and Flood Control - Improvement Program" City of Linden, New Jersey. By Parsons, Brinckerhoff, Quade & Douglas. April 1962.
(5) "Sewerage, Drainage and Flood Control - Improvement Program" City of Elizabeth, New Jersey. By Parsons, Brinckerhoff, Quade & Douglas. April 1962.
(6) "Rahway River Drainage Systems Study of Potential Flooding" by Frank H. Lehr Associates, Consulting Civil Engineers August 1967.
(7) "Drainage and Flood Control Study and Master Plan" Township of Springfield, Union County, New Jersey, by Richard J. Jeske, Inc., Consulting Engineers, Springfield, N.J. October 1969.
(8) "Feasibility Report Upon Comprehensive Storm Drainage Plan" for the Borough of New Providence by Elson T. Killam Associates, Inc. Millburn, New Jersey, Hydraulic and Sanitary Engineers. June 1960.
(9) "Feasibility Study and Report Upon Storm Drainage Facilities" for the Borough of Mountainside, New Jersey. September 1962. By Elson T. Killam Associates, Inc., Hydraulic and Sanitary Engineers.
(10) "Preliminary Report Upon Storm Drainage and Sanitary Sewerage Facilities" in the Township of Clark, Union County, New Jersey, January 9, 1968. Elson T. Killam Associates, Inc., Hydraulic and Sanitary Engineers, Millburn, New Jersey.
(11) Report to Mayor and Borough Council of the Borough of Fanwood, Union County, New Jersey on Drainage Cedar Brook Branch, By Richard 0. Luster, BSCE, MSCE, Borough Engineer. Fanwood, Union County, New Jersey. December 15, 1967. - Cl - KTSON T. KILI.AM A S SOC IATTCS , INC.
(12) "Drainage and Flood Control Improvement Program", for the Borough of Kenilworth, New Jersey. By Koczur Associates, Consulting Engineers, Elizabeth, New Jersey - December 30, 1968.
(13) "Surface Water Control in New Jersey, Drainage, Flood Control and Related Policies in an Urban State." By Stephen A. Decter, Bureau of Government Research Rutgers, The State University New Brunswick, New Jersey. August 1967.
(14) "Report Upon Newark Meadows Flood Control Pumping Station", City of Newark, New Jersey, by Elson T. Killam Associates, Inc., Hydraulic and Sanitary Engineers, Millburn, New Jersey - January, 1961.
(15) "Report Upon Sanitary Sewerage and Storm Drainage Facilities for the South Side of the Township of Scotch Plains", Union County, New Jersey by Elson T. Killam Associates, Inc., Hydraulic and Sanitary Engineers, Millburn, New Jersey - March 26, 1962.
(16) "Report on Final Design of Robinsons Branch Brook Channel Improve ment and Retention Dam", prepared for City of Plainfield by Elson T. Killam Associates, Inc., Millburn, New Jersey, July 10, 1958.
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