What is an Estuary?

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Figure 1. New York-New Jersey Harbor Estuary
An estuary is a semi-enclosed coastal body of water that connects with the open sea. It is a transition zone where salt water from the ocean mixes with fresh water from rivers and land. The amount of fresh water flowing into the estuary varies from season to season and from year to year. This variation, coupled with the daily rise and fall of the tides and the consequent movement of salt water up- and down-river, creates a unique environment. Estuaries are among the most productive of the Earth's systems; more than 80 percent of all fish and shellfish use estuaries as a primary habitat or as spawning or nursery grounds. 

Estuaries also support abundant plant life and provide feeding, nesting, breeding, and nursery areas for other diverse animal life.

The Geographic Scope of the Program

The New York-New Jersey Harbor Estuary encompasses the waters of New York Harbor and the tidally influenced portions of all rivers and streams which empty into the Harbor. There is a core area (defined by the shading in Figure 1) extending from the tidal waters of the Hudson-Raritan Estuary from Piermont Marsh in New York State to an imaginary line connecting Sandy Hook, New Jersey, and Rockaway Point, New York, at the mouth of the Harbor. This imaginary line is known as the Sandy Hook-Rockaway Point Transect. The core area includes the bi-state waters of the Hudson River, Upper and Lower Bay, Arthur Kill, Kill Van Kull, and Raritan Bay. In New York, the area includes the East and Harlem Rivers and Jamaica Bay, and, in New Jersey, it includes the Hackensack, Passaic, Raritan, Shrewsbury, Navesink, and Rahway Rivers, and Newark and Sandy Hook Bays.

The Bight (as shown in Figure 2) is the ocean area extending approximately 100 miles offshore from the Sandy Hook-Rockaway Point Transect to the Continental Slope. Almost 240 miles of sandy shoreline, extending from Cape May, New Jersey, to Montauk Point, Long Island, form its landward border. There are several back bays which are located behind the barrier beaches outside the core area of the Harbor. Some of the larger back bays adjacent to the Bight are the Great South Bay, Shinnecock Bay, and Moriches Bay in New York, and Barnegat Bay, Great Bay, Great Egg Harbor, and Little Egg Harbor in New Jersey.

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Figure 2. The Bight
Economic and Ecological Values

The Harbor/Bight is clearly an economic asset. Billions of dollars are generated annually in the regional economy from boating, commercial and sport fishing, swimming, and beach-going. The Port of New York and New Jersey is the largest port on the East Coast of the United States and among the largest ports in the world. Data from the Port Authority of New York and New Jersey indicate that 38 million long tons of bulk and general cargo, valued at approximately $54.7 billion, were shipped through the Port of New York and New Jersey in 1992. The regional economy also benefits from other uses of the Harbor/Bight, including ferry transportation, which is expanding, and sightseeing. 

While it is fairly easy to quantify the economic value of the Harbor/Bight, there are numerous other values related to ecology and aesthetics which are much more difficult to price. What is the worth of a saltwater or freshwater wetland or a barrier beach as a habitat for a variety of plants and mammals, birds and reptiles--some of which are threatened or endangered? What is the value of the personal sense of well-being that comes from an afternoon of boating, fishing, or strolling along the shore?

The ecological and economic integrity of the Harbor/Bight system are clearly interdependent. For example, both New York and New Jersey have closed some commercial fisheries in portions of the Harbor. The Port has experienced economic losses due to problems associated with disposal of dredged sediments. The uncertainty of future dredging operations has also impacted the volume of shipping in the Harbor. All of these impacts are associated, at least in part, with pollution.

Over the past 100 years, there has been a decline in the abundance of commercially important fish and shellfish. Although some of this decline may be attributed to overharvesting or natural fluctuations, pollution and destruction of habitat are clearly contributing factors. For example, there have been historic declines in once-abundant oyster beds in Raritan Bay. Thriving habitats and good water quality contribute to higher shoreline residential property values and tourism revenues, and the well-being of every living creature.

Problems and Progress

By the early 1900s, nuisance and health conditions related to untreated sewage brought about an increasing demand for effective wastewater management. Sewage treatment plants were constructed in the Harbor/Bight area throughout the century, leading to improvements in environmental conditions. Nevertheless, at the time the Clean Water Act was passed in 1972, water quality in the Harbor/Bight was still poor. There were low levels of dissolved oxygen and high concentrations of coliforms, toxic metals, and organics. The region's sewage treatment plants were discharging nearly half a billion gallons per day of raw sewage to the Harbor, and half of the plants in operation were discharging effluent with only primary waste treatment. A high percentage of combined sewers in the region were not operating properly, allowing additional outpourings of raw sewage to the Harbor/Bight, sometimes even during dry weather.

In the two decades since the passage of the Clean Water Act, investments in water pollution control programs have resulted in significantly improved water quality in the region. These improvements have occurred despite an ever-increasing number of people and activities in the Harbor/Bight. Obvious sources of pollution are now regulated through permit programs, and tidal wetlands are protected. New and expanded treatment plants are providing better treatment; only two sewage treatment plants still operate below secondary treatment levels. More recently, agencies have begun to focus on the ecosystem as a whole and on inadequately controlled sources, such as combined sewer overflows (CSOs), storm water, and non-point source runoff.

Despite recent improvements in environmental conditions in the Harbor/Bight, significant problems remain. The water quality of the Harbor/Bight is still worse than it could be, and there is a substantial reservoir of toxins in the sediments and toxic contamination in biota. Many uses and values of the Harbor/Bight are still impaired from both current and past abuses. For example, human use impairments include fish consumption advisories and intermittent closures of bathing beaches. Ecosystem health and productivity impairments include declines in fish and shellfish populations.

These impairments are caused by numerous factors. The Harbor Estuary Program has decided to focus on seven elements which we believe are the primary causes of both ecosystem and human use impairments. These seven elements are habitat loss and degradation, toxic chemical contamination, contaminated dredged materials, pathogens, floatable debris, nutrients and organic enrichment, and rainfall-induced discharges.