THE GOWANUS PROBLEM
By
Allison Houston
Environmental Studies 1
Professors Tomkiewicz and Klein
December 21, 1999
In the late nineteen century
the Gowanus canal was a significant waterway for New York City's commerce.
Several industries lined its banks including heavy chemical, coal and gas
manufacturing plants, oil refineries as well as a paint plant. By the turn of the century the government
recognized the activities of the canal had caused it to become extremely
polluted. In an effort to remove the pollutants, the city built a
"Flushing Tunnel" in 1911 but unfortunately it shut down due to
mechanical failure in the 1960's. As the canal returned to its former polluted
and stagnant state, it also became a source of discomfort and concern for the
residents in the surrounding community. The main concern was the potential
health risk the canal posed to its immediate environment. In the thirty-seven
years following the tunnel shutdown the waterway was continuously abused
without any form of release. As the water became more polluted it lost most of
its beneficial uses as well.
The beneficial and detrimental uses of the canal
The commercial use of the waterway was by far one of the main sources of pollutions. Shipping contributed to the vast amount of submerged and floating debris. The use of the canal by heavy chemical industries and the presence of both a metal and paint plant were detrimental factors that caused oil and grease floatables, pathogenic agents, toxicity to aquatic life and color, odor and turbidity problems. Wastewater disposal, which included the overflow of sewage treatment plants runoff due to heavy rains, emptied directly into the Gowanus. This was a main source of suspended material that contributed to the destruction of benthic communities and oxygen depletion. Fortunately, the opening of The Red Hook Pollution control Plant in 1987 reduced sewage flow into the canal. Garbage disposal including residents illegally dumping waste was aesthetically objectionable and may also have helped to destroy the benthic communities.
In
the good days, the canal was known for having an extremely large shellfish population
and while these creatures were not a harmful factor, they did however require a
low level of pathogenic microorganisms, suitable substrate and adequate food to
survive. When these features were lost the shellfish died. Swimming also wasn’t
a damaging factor but it too required low levels of pathogenic agents and
aesthetic acceptability. Wildlife (birds, waterfowl) survival depended on an
exclusive use of the canal as well as adequate food, while the survival of fish
required adequate food and dissolved oxygen.
As
the water quality became more undesirable, interest began to increase as people
became aware of the water’s state. It became apparent that the aesthetic
quality was becoming increasingly low. Wildlife was seen less, and since
aesthetically unappealing conditions now existed, it was certain that problems
associated with other beneficial uses of the water also existed. The fact that
the water released a pungent aroma (as the result of decomposing sewage sludge)
indicated that, dissolved oxygen was reduced so that a healthy biotic system
was absent. The recreational potential of the water was basically eliminated as
it became grossly polluted. Activities such as swimming were not even a
consideration. To do so one would literally be risking death. This fact was
confirmed in 1972 when tests discovered that there was live hepatitis, typhoid
and a virulent strain of cholera in the canal. In October 1997, Ben Langstreth
in an effort to repopulate the canal with oysters placed 120 oysters in a
cylindrical net into the Gowanus. Two weeks later when he returned, he found
the net void of all but a few empty shells. No conclusion was drawn from their
disappearance or on the water’s ability to support life, however there are
speculations that rats may have eaten the oysters during the low tide.
One thing is certain, Gowanus pollution occurred as a result of a series of complicated activities in it. Because the canal had supported a wide spectrum of beneficial uses, the quality requirement of the water and its environment were necessarily complex. As a result, conflicts arose among these uses and the detrimental factors associated with them. In 1992, the city's Department of Environment and Protection (DEP) began designing the repair and restoration of the flushing tunnel and actually started construction in 1995. One of the first things that the project entailed was assessment of the water quality.
Methods of testing and assessing the water quality
For
years, the Department of Environment and Protection (DEP) has monitored the
water quality of the Gowanus, like it did other regional water bodies. Since there are no single water quality
criteria for waterways, several indicators are commonly used to describe water
quality. Table 1[2] below, shows
tentative water quality criteria for New York’s harbor water. Included in the
table are two beneficial uses, recreation (which includes health) and the
protection of aquatic life. Table 2[3]
shows the actual data of The Gowanus prior to the reactivation of the tunnel
and Table 3 shows data of water quality since the tunnel reopening. An evaluation of the water was necessary for
assessment of the effect of reopening the flushing tunnel. It is important in
establishing and judging the improvement in the canal’s water.
Table 1: Water quality standards
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Categories of Use
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|
Quality characteristics |
Recreation
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Protection of
aqauatic biota |
Related water characteristics |
|
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Aesthetics |
Health |
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|
|
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|
Total coliforms |
|
Median </ml |
|
Total coliform |
|
Fecal coliforms |
|
Log mean </ml |
|
Fecal coliform |
|
Dissolved oxygen |
|
|
> 5.0 mg/1 |
BOD Biostimulants Settleable solids Suspended solids |
|
Microplankton |
< 500 cells per ml |
|
|
Biostimulants Turbidity |
|
Benthic animal diversity |
|
|
> 80% of normal |
Toxicity Settleable solids |
|
Transparency (Secchi disc) |
> 2 m |
|
|
Turbidity elements |
|
Sediment BOD |
|
|
< 4 mg/g |
BOD Settleable solids Suspended solids |
|
Chlorinated hydrocarbons |
|
|
< 50 ug/1 |
Chlorinated hydrocarbons |
|
Floatable hexane extractable materials |
<2 mg/m2 (water) < 0.3 g/m2 (shore) |
|
|
Oils and greases |
|
Floatable particulates |
|
|
(none yet proposed) |
Floatable particulates |
|
Temperature |
T < 85o F |
|
^ T < 4o F (winter) ^ T < 1.5o F (summer) |
Temperature |
Table 2: Water quality of the Gowanus prior to
May 1999
Total coliform NA
Dissolved oxygen <1.5mg/l
Microplankton NA
Transparency 2ft
Floatable particulates wide variety of debris
Color purple/lavender
PH NA
Odor objectionable
Chemicals lead/pcbs/mercury
Table 3: Water quality of the Gowanus since May 1999
Total coliform NA
Dissolved oxygen >5mg/l
Microplankton NA
Tranperancy 3ft
Color No color
pH 7.4
Odor acceptable
On May 3, 1999, the work on the flushing tunnel was finally completed and it was reopened. Prior to reopening of the tunnel, the DEP first dredged the area around the mouth of the tunnel to prevent sediments from being stirred up when the daily average 200 million gallons of water started flowing into the canal. Additionally, DEP continues to monitor the quality of the water for the following: total coliform, dissolve oxygen, nitrates, phosphate, transparency and pH levels.
It is hoped that as the tunnel continues to operate 24 hours per day bringing fresh water to the canal and removing contaminants, it will eventually return to its former glory. Wildlife, fish, shellfish and even humans may once again flock the banks of the canal. From the difference in the quality of water before and since the reactivation of the tunnel it is obvious that there is hope for the canal. However there is still much more cleaning up to be done before such activities can be possible.