Abstract
In May 1985, a National Pollutant Discharge
Elimination System permit was issued for the Department
of Energy’s Y-12 National Security Complex (Y-12
Complex) in Oak Ridge, Tennessee, USA, allowing discharge
of effluents to East Fork Poplar Creek (EFPC). The
effluents ranged from large volumes of chlorinated oncethrough
cooling water and cooling tower blow-down to
smaller discharges of treated and untreated process
wastewaters, which contained a mixture of heavy metals,
organics, and nutrients, especially nitrates. As a condition
of the permit, a Biological Monitoring and Abatement
Program (BMAP) was developed to meet two major
objectives: demonstrate that the established effluent limitations
were protecting the classified uses of EFPC, and
document the ecological effects resulting from implementing
a Water Pollution Control Program at the Y-12
Complex. The second objective is the primary focus of the
other papers in this special series. This paper provides a
history of pollution and the remedial actions that were
implemented; describes the geographic setting of the study
area; and characterizes the physicochemical attributes of
the sampling sites, including changes in stream flow and
temperature that occurred during implementation of the
BMAP. Most of the actions taken under the Water Pollution
Control Program were completed between 1986 and
1998, with as many as four years elapsing between some of
the most significant actions. The Water Pollution Control
Program included constructing nine new wastewater
treatment facilities and implementation of several other
pollution-reducing measures, such as a best management
practices plan; area-source pollution control management;
and various spill-prevention projects. Many of the major
actions had readily discernable effects on the chemical and
physical conditions of EFPC. As controls on effluents
entering the stream were implemented, pollutant concentrations
generally declined and, at least initially, the volume
of water discharged from the Y-12 Complex declined.
This reduction in discharge was of ecological concern and
led to implementation of a flow management program for
EFPC. Implementing flow management, in turn, led to
substantial changes in chemical and physical conditions of
the stream: stream discharge nearly doubled and stream
temperatures decreased, becoming more similar to those in
reference streams. While water quality clearly improved,
meeting water quality standards alone does not guarantee
protection of a waterbody’s biological integrity. Results
from studies on the ecological changes stemming from
pollution-reduction actions, such as those presented in this
series, also are needed to understand how best to restore or
protect biological integrity and enhance ecological recovery
in stream ecosystems. With a better knowledge of the
ecological consequences of their decisions, environmental
managers can better evaluate alternative actions and more
accurately predict their effects.
