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author | rekado <rekado@elephly.net> | 2013-05-10 14:33:53 +0800 |
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committer | rekado <rekado@elephly.net> | 2013-05-10 14:33:53 +0800 |
commit | bc3f1b6f6533c80f8a9853624f6ea5eabb67049c (patch) | |
tree | 71ce4dba290cac961ebb935dbdd0e19c491f50ea | |
parent | 1bf633123da503a3bd04374590fff64a85dcbd66 (diff) |
almost finished significance section
-rw-r--r-- | assignment2/significance.tex | 93 |
1 files changed, 49 insertions, 44 deletions
diff --git a/assignment2/significance.tex b/assignment2/significance.tex index 596f71a..427c155 100644 --- a/assignment2/significance.tex +++ b/assignment2/significance.tex @@ -22,6 +22,25 @@ 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, enlargen 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 @@ -67,48 +86,34 @@ Following a limits-based approach and with the help of a monitoring network, 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 -water 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 wastewaster 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 compunds, 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. - - -(third part of lawrence): important to assess significance of -*positive effects* to see if they are worth the negative impacts. - -- positive effects can be quantified, but it is not clear how to weigh - potential economic benefits against expected negative impacts on the - biophysical environment without imposing market norms on intrinsic - ecosystem values. - -- other impacts cannot easily be quanitifed - -% - talk about drawbacks mentioned in \textcite{lawrence-approach} -% \begin{quote} -% 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. -% \end{quote} - +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 wastewaster 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 compunds, 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. -- significant impacts: - - likelihood - - effects that affect sensitive parameters
\ No newline at end of file +Other impacts cannot easily be quanitifed. 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.
\ No newline at end of file |