The divide between the streams that flow into the Delaware River and
Delaware Bay on the west and those that flow into the Hudson River,
Newark Bay, New York Bay, Raritan Bay, Sandy Hook Bay, and Atlantic
Ocean on the east is a very irregular line extending from the northwest
corner of the state to Cape May. It is so near the Delaware River and
Delaware Bay that only a little more than one third of the state is
drained into these waters. The tributaries which drain this basin are,
therefore, small. The eastern drainage area contains several rivers
of considerable size. The Wallkill River flows northeast through the
northwestern part of this state and through the southeast corner of
New York into the Hudson River. The Hackensack River rises in New
York and flows south into Newark Bay. The Passaic River, which has as
tributaries Saddle River, Pompton River, Ramapo River, Wanaque River
with Greenwood Lake, Pequannock River, and Rockaway River, follows
a very tortuous course and flows into Newark Bay. Just north of the
middle of the state is the Raritan River, which rises near the Delaware
River and flows into Raritan Bay.
All the rivers which flow into the Atlantic Ocean or into the bays
which border the state are affected by the tidal flow, and the largest
are navigable for at least some parts of their courses. In the case
of the Delaware the tide extends to Trenton. Important cities which
are located on tidal waters are Hoboken, Jersey City, Bayonne, Newark,
Elizabeth, New Brunswick, Perth Amboy, Long Branch, Asbury Park,
Atlantic City, Camden, and Trenton.
Between the Watchung Mountains on the east and south and the Highlands
on the northwest is a broad, flat basin, which is drained by the
Passaic River. Before the Glacial Period the Passaic River did not flow
from this basin through the mountains at Little Falls and Paterson, as
it does now. This area was then drained by a stream which crossed the
Watchung Mountains near Summit and Millburn and flowed southeast into
the sea. During the Glacial Period most of this basin was covered by
the ice sheet. As the ice receded, this gap in the Watchung Mountains
was filled with glacial drift and there was formed a large lake, which
the geologists call Lake Passaic and which was drained for a long time
by a stream which flowed southwest through the hills near Liberty
Corner into the Raritan River. As the ice sheet receded still farther
north, the gaps through the mountains at Little Falls and Paterson were
exposed. As these gaps are lower than the older outlets, the water
of Lake Passaic escaped through them over the present course of the
Passaic River to Newark Bay, and the lake disappeared. These changes in
the drainage of the Passaic basin explain the presence of much swampy
land in this section.
The water power generated by the rapid descent of the streams in the
part of the state lying north of the Fall Line has long been utilized
for manufacturing purposes, and mills are found along all the streams
in this part of the state. The location of Paterson as a manufacturing
center is due to the water power developed from the Passaic Falls. At
Trenton, water power is secured from the rapids of the Delaware River.
In the northern part of the state, several streams and lakes are used
to provide electric power and light.
Closely connected with drainage systems and dependent largely upon them
are the methods of supplying water to the people of towns and cities
for domestic purposes. Formerly water for such purposes was obtained
from near-by springs, wells, and streams. As population increased,
the local sources of water supply became contaminated and dangerous
to health. This danger and the larger quantity of water required by
the increased population and by manufacturing interests have forced
the larger cities to make provision for securing their water supply
from sources, more or less remote, which are not subject to pollution.
Their water-supply systems include pumping stations, reservoirs for
storage, and long pipe lines. The drainage basins from which water is
taken for municipal purposes are located in the thinly populated parts
of the state. The northern mountainous section, which is not specially
profitable for agriculture and other purposes, is particularly useful
in furnishing sources of water supply. The many large cities in the
northern part of the state draw their water from the upper parts of the
Hackensack, Passaic, and Raritan basins. Formerly Newark and Jersey
City drew their water from the Passaic River not far above the former
city. This river was gradually so polluted by the sewage and the waste
of factories discharged into it, that it had to be abandoned as a
source of supply. These cities now bring their water long distances,
Newark using the Pequannock basin, and Jersey City the Rockaway. In
some cases water is obtained from artesian wells.
The pollution of streams by city sewers and drains from factories
destroys fish in fresh-water streams. The damage extends even into
tidal waters, and many oyster and clam fisheries in the bays have
been abandoned. The state is alive to the necessity of protecting its
streams against contamination of all kinds and has enacted legislation
designed to maintain their purity by preventing the flow of sewage
and other objectionable matter into them. It has provided for the
construction of a trunk-line sewer along the valley of the Passaic from
Paterson to the sea, into which the sewers of the cities along its
course will be discharged. In cooperation with Pennsylvania the state
has passed laws to prevent the pollution of the Delaware River.