Conducting the Environmental Impact Analysis and Assessment - Environmental Impact Analysis: Process and Methods - page 202

in the literature, and in most cases, the results were found to represent a com-
monly observed relationship. For the relationship between organic carbon load-
ing and the benthic community quantified in the MERL experiment (Maughan
and Oviatt 1993) there was a strong agreement with other investigations
(Bascom et al. 1978 and Person and Rosenberg 1978) that permitted establishing
impact significant criteria strongly supported by scientific investigations (Table
5.3). These criteria could then be used in the environmental impact analysis of
the EPA-funded 201 program to upgrade and expand the nation's municipal
wastewater treatment system. As discussed in Section 5.3.5, these criteria were
used directly in the Boston Harbor Wastewater Cleanup EIS, which addressed
one of the largest wastewater treatment facilities in the country with one of the
longest wastewater effluent outfalls and diffusers.

5.3.4 Impact Prediction of DCR Management in the Great Lakes

An interesting and informative approach to impact prediction was used in
the USCG environmental analysis of DCR discharged to the Great Lakes (see
Section 10.2 for a summary of the background on the DCR EIS). The analysis
was conducted to meet a Congressional directive, achieve NEPA compliance,
and promulgate rules and regulations governing the management of DCR.
The approach is described in the next section, followed by a comparison with
another and quite different NEPA approach, addressing impacts to similar
environmental resources.

TABLE 5.3
Impact Significance Criteria for Estuarine Benthic Communities Derived from
Environmental Impact Research

MERL
Low
Organic
Loading

MERL
Medium
Organic
Loading

MERL
High
Organic
Loading

MERL
Control Normal a Changed Degraded

Excess
carbon
loading
above
back ground
m 2 /day

0 <0.1 0.3 0.1- 0.5 1.3 1.5-3.1 2.7

Pollution-
tolerant
species,
% of total
fauna

34 88 51 36 71 11 76

Percentage of
biomass in
normal area

100 100 136 270 209 470 244

Source: Maughan, J.T. and C.A. Oviatt. Water Environment Research . 1993.

a

Bascom, W., A.J. Mearns, and J.Q. Ward. Establishing boundaries between normal, changed and degraded
areas. W. Bascom, ed. Coastal Water Research Project Annual Report 81. 1978.