% 1070 words
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% Explain how you would identify the significant effects. Discuss
% any difficulties in determining the significance of effects in EIA

\section{Significance}

The process of impact assessment is conceptually open-ended. As one of
its major goals is to aid a decision-making process, however, each
step in the assessment must be completed within a given time
frame. Hence, limits are imposed on the level of detail, the length of
the time period for which impacts can be assessed at the expected
level of detail, and the number of interactions that can reasonably be
considered.  To set these limits, judgments must be made on how
significant each potential impact is, a decision on how much detail
and how much effort in avoiding or mitigating the impact is
appropriate, and whether the residual impact is insignificant enough
to be acceptable.  These judgments are crucially guided by the
practitioners' own values and the values they consider in the
evaluation process \parencite{lawrence}.  As the determination of
significance is inherently subjective, it should not be an activity
performed only by experts and with a claim to objectivity, but should
aim to be a collaborative procedure guided by reasoned
discourse \parencite{lawrence-approach}.

One of the goals of impact assessment is to weigh the desired positive
impacts of a proposal against the expected negative impacts in order
to evaluate whether the project plan should be pursued or discarded.
The dairy factory could, for example, result in an increase in the
number of employment opportunities, enlarge the economic basis of the
region, increase the country's export volume, etc. While it is
possible to quantify many of these positive effects (e.g. by
estimating from experience with similar projects) it is not clear how
to weigh these potential economic benefits against the expected
negative impacts on the biophysical and social environment without
imposing market norms on intrinsic ecosystem and community
values. Just how much more valuable is the somewhat polluted river now
compared to a somewhat \emph{more} polluted river if the project was
implemented? Involving the public in a collaborative approach may not
lead to satisfying results. As \textcite{lawrence-approach} writes,
``the collaborative approach is viewed as too quickly equating public
concerns and issues with impact significance, at the expense of other
sources of insight and knowledge.''

According to \textcite{lawrence-approach}, the approach to determining
impact significance is usually ``limited to ad hoc and inconsistent
judgments with reasons and/or to the staged application of thresholds
and/or criteria.''  The Resource Management Act 1991 does not
prescribe a process for the assessment of significant effects. As all
major projects require resource consents, however, impact significance
is, in practice, reflected by the management plans and established by
resource consent decisions of regional and territorial councils. The
Ministry for the Environment bemoans that a ``lack of clarity and
certainty in some regional plans (eg, a lack of enforceable limits)
has led to issues being decided consent by consent and often
re-litigated'', resulting in ``decision-making processes [that] are
litigious, resource-consuming and create
uncertainty'' \parencite[p. 18][]{freshwater-reform}.

Since the National Policy Statement for Freshwater Management (2011)
the ``national values of fresh water'' have been made explicit, but
their postulation does not give rise to a guideline by which the
significance of activities affecting these values could be
determined. For example, the statement made in the NPSFM that water is
valued for ``cleaning, dilution and disposal of waste'' conflicts with
the statement about respecting water's intrinsic values such as ``the
natural conditions of fresh water, free from biological or chemical
alterations resulting from human activity'' \parencite{npsfm-guide}.
Resolving this ambiguity, the NPSFM intends a limits-based regime to
be established where regional councils are expected to collaborate
with the community to translate individual values and freshwater
objectives into enforceable limits for individual
water bodies \parencite[][p. 14]{npsfm-guide}.  The implementation and
enforcement of this National Policy Statement---and pending its
implementation, decisions relating to the significance of project
impacts on the environment---crucially depend on a sound information
base derived from regular monitoring.  The National River Water
Quality Network enables the measurement of various water quality
indicators (e.g. temperature, dissolved oxygen, turbidity, nutrients
etc.) at 77 sites and has been used to measure nation-wide water
quality trends. In total there are about 600 monitoring
sites \parencite{nrwqn}.

%According to the \emph{Environment New Zealand 2007} report ... % say something about water quality trends?

Following a limits-based approach and with the help of monitoring
networks, it would be practical to impose absolute limits for a variety
of water health indicators. Whether a residual impact on the physical
environment is significant or not then is a matter of setting measured
trends against the expected level of the impacts of a proposed
activity. In the case of the planned dairy factory, the significance
of the impact of discharging warm water into the river not only
depends on the absolute value of the temperature difference between
wastewater and river water, but also on the cumulative temperature
increase due to human activity reflected in the mean temperature of
the affected body of water. Case studies can be used to estimate the
magnitude of the impact. If the limit on water temperature would be
exceeded by the plant's wastewater discharge, the impact would be
rated as significant and in need of mitigation to avoid significant
effects on the aquatic ecosystem. The same approach is applicable for
any impact that affects quantifiable environmental properties, such as
the release of organic and inorganic compounds, or the contamination
with residual antibiotics and pesticides.  According to the
description, the river is already used as a sink for the wastewater of
another dairy factory; dairy farming is said to have expanded in this
area, indicating that the inflow of organic and inorganic components
from farm effluent and non-point sources has also increased. It is
likely that under these circumstances, the cumulative impacts of
wastewater discharge would be deemed significant.

Other impacts cannot easily be quantified. This includes higher-order
impacts such as the stress that an increased number of workers may
exert on local community services. The likelihood of these impacts
depends on the state of local facilities and the cumulative workload
they are sustaining.  As it is difficult to find appropriate
indicators for the state of social values and impractical at best to
set upper limits for such ill-defined concepts, a limit-based approach
to significance estimation is unlikely to succeed.  This is an area
where there is probably no better way to assess significance than
to ask for direct community involvement.