Conducting the Environmental Impact Analysis and Assessment - Environmental Impact Analysis: Process and Methods - page 173

must the discharge be in order to avoid enriching the river and nearshore
system?
This situation reflects a meaningful comparison of alternatives and ulti-
mately a decision centered on the major issues, as discussed in Section 4.5.
Both alternatives (advanced treatment with nearshore discharge or extended
effluent discharge) met the purpose and need of eliminating failing septic
systems and the associated degradation of the estuarine environment while
not exacerbating and in fact, potentially improving conditions resulting from
nutrient and organic loading. So the comparison of alternatives was based on
cost, reliability of treatment, construction impacts, and other benefits associ-
ated with each alternative.
The challenge of describing the affected environment was to fully under-
stand the nutrient and organic loading to the system and how it affected
the eutrophic status of the estuary and nearshore environment (Cibik and
Maughan 1991). This information would then be the primary input in deter-
mining the exact level of advanced wastewater treatment for the North River
discharge alternative and exactly how far offshore the outfall must be for
the other alternative. The challenge was approached consistently with the
described process (Section 5.2.2) of thoroughly reviewing available informa-
tion and supplementing with original data collection only where necessary.
This mandatory first step in describing the affected environment was all that
was necessary for the advanced treatment/marsh discharge alternative. The
existing information available from such sources as the state's monitoring
program and studies commissioned by the North River watershed association
revealed that the North River system was healthy, but very near its assimila-
tive capacity. Any substantial increase in nutrient or organic loading could
push the system beyond its capacity to process the load and result in excessive
plant growth and oxygen demand. Thus the literature review fully defined
nutrient and organic loading to the system and how it affected the eutrophic
status of the estuary. It also provided the necessary input to fully develop the
details of the advanced treatment alternative: in order to avoid degradation
of water quality and estuarine habitat, the nutrient and organic load associ-
ated with the increased wastewater flow had to be offset by a wastewater
treatment process with a higher removal rate. In fact, the affected environ-
ment evaluation revealed that the system was close enough to the assimilative
capacity that a margin of safety was appropriate and the total nutrient and
organic load to the system must actually be less than the current load. Using
this information, the wastewater treatment process needed to accomplish the
reduced load could be defined and the cost of implementation calculated.
The existing information was not adequate to understand offshore
conditions and an original investigation was necessary. The challenge
to the environmental analysis team was that it is a “big ocean” (actually
Massachusetts Bay) out there, and available financial resources, personnel,
and schedule limited the scope of any original investigation and required