Annexure - Hydrogeology: Objectives, Methods, Applications - page 321

• provide enough time to put in place prevention or attenuation
measures. An initial identifi cation exercise will be undertaken in 2009,
and renewed at most every 6 years;
• take into account the temporal characteristics of the aquifer (fl ow,
infi ltration).
The data, conforming to international monitoring principles, must be of
scientifi c quality and of equivalent comparability. Regression type statistical
methods will be used for specifi c monitoring points. The identifi cation of
trends will also rely on archive data, predating the monitoring system.
The beginning of a trend reversal will be considered to be the point at
which the concentration is greater than 75% of the standard value, except in
the case where an earlier or later starting point is necessary in order to limit
the economic cost of the degradation. A starting point for a trend reversal
will be valid for the entire subsequent 6-year period.