Working In The System: Parameter Identification And Aggregation

What is relevant in the environment itself, that is, what are the parameters of environ- mental quality, depends on the higher normative principles laid down in the final vari- And, conversely, aggregating environmental quality parameters into a more con- densed quality assessment is, or at least should be, aggregation 'back up' towards the final variables. The present section aims to describe and discuss this process of going down and back up, environmental quality parameter identification and aggregation for assessment, respectively, in two subsections. Since the assessment of environ- mental quality is conceptually equal to the assessment of (predicted) changes in environmental quality due to some (proposed) activity, methodologies will be included in the second subsection.

From final variables to environmental quality parameters

As Bouwer and Groenenberg (1991) assert, the Latin root meaning of is non-normative. We still use this denotation, for instance, when we say that somebody is a member of a certain committee "in his quality of being mayor" and in a term like "qualitative research", meaning that the research focuses more on what something is than on its distribution. Later, the term quality also took on a normative denotation. We use that meaning, for instance, when we say that something is "a quality

It is this denotation that predominates in environmental science and policy. We see it, for instance, in terms like "water quality law" or "Council on Environmental

quality, here, is always something that is aimed at, not just a description of how the environment happens to be. A quality assessment then always entails some comparison between environmental conditions as they are and the conditions as desired (the The linguistic proof is that we may evaluate a water quality as "high" because low toxic substance concentrations. The term 'high' denotes that the factual (low) concentrations lie close to the (low) desired

the concept of environmental quality is in fact simply the complement of the concept of environmental problem, if we state the environmental problem in terms of environmental parameters, not actions or impacts (Fig. 3J); both are comparisons of the actual and desired world. If quality is low, the problem is if facts and norms match the quality is perfect and the problem is zero (Udo de Haes, 1984).

Taking a closer look we find that when speaking about "high" or "low" quality, we take quality as an open concept which may vary between zero and perfect. In a term like "quality product" the quality concept is closed, we could say; it can mean good quality only. I use the open concept throughout, following the usage that we do not speak about "a quality water" or "a quality landscape"

The facts and values (norms) that make up environmental quality are facts and values in terms of environmental quality characteristics (or These may be defined as all characteristics (or parameters) of the environment causally related to the final variables or, alternatively, to the Junctions of the environment. The term 'parameters' here is in wider use than The drawback of 'parameter' is that it tends to focus the attention on relatively 'little' characteristics, such as the ones found in the well-known lists of water and air I will use the terms interchangeably. The quality characteristics, as said in the preceding section, concern all final variables, from health and economy to the more spiritual and ethical ones. So, environmental quality characteristics are the sulphur dioxide in the the maize in the field, the fish you can catch and sell, the wind that cools you off, the mountain that is your challenge, the great whales that share the world with you.

The term 'causally related' has been used for a special reason, namely, to distin- guish the concept of environmental quality characteristics or parameters from the concept of what I here call environmental quality indicators. This distinction is important to avoid confusion and double-counting, as the following example will Searching for an environmental quality parameter for temperate lakes from the final variables downward, one of the first parameters we may identify is the occur- rence of commercially interesting fish, say, the trout. Then, we see that the trout may also be linked to a more spiritual final variable, say, something like 'wilderness value', connected to the possibility of lone hikers to live off nature in close, direct interaction. Third, the trout is an intrinsic value of its own. (Note that this is not a case of undue double-counting; 'trout value' really is these three.) This is the simple situation depicted in the top picture in Figure 4B: the trout is causally connected to three elements (small circles) in three final variable blocks, and the identification of the trout as a quality parameter runs along the three dotted lines downward.

Next, ecological models or experience may show that the trout is always there if dissolved oxygen concentrations are high enough. It might then be decided, for instance because it is cheaper to monitor, to take dissolved oxygen as the quality parameter, as shown in picture 2 of Figure 4B. The trout is simply passed through by the dotted lines and dissolved oxygen acquires all 'trout (Note that taking them both would be a case of undue double counting.)

The next picture (3) shows the situation arising when it is discovered that dis- solved oxygen is not only causally linked to the trout, but also to the fate of toxic substances entering the lake; high dissolved oxygen concentrations prevent toxicants dissolving out of sediments, for instance. Now, through some 'toxicant'

as we do with products.

See, for instance, House (1990) for the UK water quality parameters (dissolved oxygen, dissolved arsenic, total coliforms, etc.).

I use the distinction between parameter and indicator here only for the conceptual purpose of this section. Therefore, I ignore the wide variety of existing definitions, typologies and terminological discussions.

toxi- cant t i ïïl\ diss. oxygen = parameter = indicator Figure 4B

Parameters and indicators of environmental quality. At the top of each picture are the final variables. The upward lines are the downward lines are as in all

figures (e.g.

variable, dissolved oxygen also acquires a health value; it still remains the only environmental quality parameter.

In picture 4, the first indicator appears. It may transpire, for instance, that some small organism is both very susceptible to low oxygen concentrations and quite easy to sample; because it survives only when oxygen is high all the time, it may need sampling perhaps only once a year, or it may be a good 'early when oxygen instabilities start to occur. Note, however, that the benthic organism is not causally related (other than 'backwards' through the oxygen parameter) to the final variables; it is not a quality parameter. It acquires all 'health' and 'trout' values, as the dotted lines show, but the dotted lines do not follow the links anymore.

Picture 5 shows what may happen if it turns out that a high dissolved oxygen concentration may not be the only condition for trout survival. Water turbidity, for instance, related to upstream erosion, may play a role too. Then, oxygen having become an unreliable stand-in, monitoring of the trout may be re-installed. The benthic organism now only carries relevance as a health risk indicator, as the picture shows. Next (picture 6), it may occur to the ecologists that sampling the benthic organism is not really much use Might it not be the case that if the trout disappears oxygen may still be high, but as long as it is there, oxygen will certainly be high enough to forestall health risks? If so, the trout may be taken not only as a parameter for its own three final variables, but also as an indicator for environmental health. The trout now serves both roles and carries all the relevances the benthic organism had in picture 4.

Picture 7 shows the situation occurring when it has been decided that dissolved oxygen must nevertheless be measured, for instance because it is a legal requirement. In such a case, the weight given to the oxygen concentration in the overall quality assessment should reflect the health value only; the trout take care of the 'trout- related' values.

Obviously, this story may go on and on. We may, for instance, find that the level of the toxic substance in trout tissue is a health-related parameter. Then, we could also consider taking the toxic concentration in the trout tissue not only as a health-related parameter, but also as an indicator for the toxicant's concentration in the water; the trout may even disappear completely at only slightly elevated levels of toxicants (Hodson, 1990). Note, however, that in spite of these ecological complexities, all pictures can remain clear and relatively simple, conceptually, if we keep track of the difference between parameter and indicator.

The search for environmental quality parameters and indicators has received much attention in the last decade, up to the point that, as Rapport (1990) puts it, "convening seminars on the topic appears to have become a spring ritual". Going through the literature that has been generated by these seminars, I have not been able to escape the impression that largely missing in it is the very thing that has provided the basic simplicity, relevance and logic of the pictures in Figure the connectedness to the final variables, i.e. the relationships between the parameters and environmental objectives and problems. This impression is nicely summarized by a working group

of one of these seminars (Day, 1990), that had been given a Table Of Practical Criteria For Parameter Selection to work on:

criterion. The group felt that number 1 in the Table should be defini- tion the problem, before indicators are

In my experience (Van den Berg and De Groot, 1988; Van der Voet and Van der Naald, 1987), a line of parameter identification reasoning strictly from the final variables downward yields a set of parameters different from the ones in current use. One of the reasons is that this line of reasoning tends to stop when empirical models begin to fail; one then ends up with parameters relatively high up in the environmental effects chain (Figure 6J), e.g. toxic substances in fish instead of toxic substances in deep lake sediments. At the same time, it is clear that these sediments should some- how be monitored, and that the ecologists should be allowed to pursue and test their intuitions about 'early warning' indicators and other phenomena as yet formally unconnected to the final variables. (1988) calls this the "bottom-up" line of indicator research. It may therefore be conjectured (De Groot, that the follow- ing 'three-layer' structure for further development might be useful:

(1) A layer of 'top-down' research, using relatively finalized models and nor- mative procedures to derive politically, logically and empirically grounded sets of environmental quality characteristics from the final variables downward. The results should be used in formal monitoring activities, scoping procedures and so on.

(2) An 'interactive layer' of applied environmental modelling, where specialist scientists bring in their inspirations, tools and knowledge from and problem- oriented environmental scientists, from 'above', bring in the capacity to focus research on the relevant areas and to cross disciplinary boundaries.

(3) And a 'bottom-up' layer, where scientists are free to lay foundations and pursue their own intuitions with respect to what might be relevant parameters and indicators.

Although the example of the present subsection has been taken from also social scientists and philosophers have a role to play in the search for environmental quality parameters. Environmental quality discussions tend to focus heavily on natural- scientific characteristics, but environmental quality is also its education value for young children, its visual landscape quality and so on. The criticism of the philosopher Vest (1987) against the way the concept of wilderness solitude has been operationa-

It may be noted as well that the example has focused on environmental not the

final variable. As said in preceding section, often does not add to a set of parameters to be assessed or monitored, but sometimes it does. As for the first repeated measurements (of toxic substances, trout, organic soil matter, etc.) is the approach to long-term trends. The second category are the special 'sustainability One group here are the 'early warning' indicators, such as lichen growth abnormalities indicating that forest may be immi- nent. A second group concerns the direct measurement of processes that do not add to or from present quality but irreversibly after future quality. Low but persistent soil erosion rates are an example 1990). Another is the ground water level in peat soils used for agriculture; the dryer the soil, the faster it oxidizes away.