Geoscience Reference
In-Depth Information
the middle of the twentieth century the small
towns along the Nashua (Gardner, Fitchburg,
Leominster and Nashua) were home to paper,
textile and shoe factories, many of which were
extracting water from the river and then dis-
charging untreated waste back into the river. The
photograph of the Nashua in 1965 (Plate 9) is
indicative of the pollution problems experienced
in the river; in this case dye from a local paper
factory has turned the river red. Under the US
water-quality classification scheme the river was
classified as U: unfit to receive further sewage.
In 1965 the Nashua River Clean-Up Committee
was set up to try to instigate a plan of restoring
the water quality in the river. This committee later
became the Nashua River Watershed Association
(NRWA) which still works today to improve
water-quality standards in the area. Between 1972
and 1991 eleven waste water-treatment plants
were constructed or upgraded to treat waste from
domestic, and to a lesser extent from industrial,
sources in the catchment. These were built using
grants from the state and federal government as
part of a strategy to improve the river from U to
B status (fit for fishing and swimming). Through
this control of point source pollution the river-
water quality has improved dramatically as can
be seen in the second photograph of the river
(Plate 10). The river has attained B status and is
an important recreational asset for the region. It
has not returned to a pristine state, though, and is
unlikely to while there is still a significant urban
population in the catchment. There are problems
with combined sewage and stormwater drainage
systems discharging untreated waste into the river
during large storms, and also diffuse pollution
sources - particularly in the urban environment.
However, during the latter half of the twentieth
century the Nashua river has had its water quality
transformed from an abiotic sewer into a clean
NEW
HAMPSHIRE
Nashua
catchment
Nashua
MASSACHUSETTS
Figure 7.7
Location of the Nashua catchment in
north-east USA.
river capable of maintaining a healthy salmonid
fish population. This has largely been achieved
through the control of point pollution sources.
The author gratefully acknowledges the Nashua
River Watershed Association for supplying much
of this information and Plates 9 and 10. For more
information on the NRWA visit: http://www.
nashuariverwatershed.org/
disposal creates no harmful side effects. In the United
Kingdom the control of point source pollution is
through discharge consents. These provide a legal
limit for worst-case scenarios - for example, at indi-
vidual sewage treatment works they are usually set
with respect to TSS, BOD and ammonia (sometimes
heavy metals are included), and calculated to allow
Controlling point source pollutants
The control of point source pollutants cannot always
be achieved by removing that point source. It is part
of water resource management to recognise that
there may be valid reasons for disposing of waste in
a river; effective management ensures that waste
