1. Umweltbundesamt, Austria
A reminder of previous CIS recommendations: Monitoring (WG 2.7) and Statistics (WG 2.8)
Andreas Scheidleder
Umweltbundesamt, Austria

2. WFD (Art 8, Annex V)
Monitoring is required for
Providing reliable assessment of status (quantitative & chemical)
Estimate direction and flow rate in transb. GWB
Supplement/validate impact assessment
Detecting significant sustained upward trends of pollutants
Assessing trend reversal of pollutants

3. WG 2.7 Monitoring
WG 2.7 Monitoring – Key principles
The amount of groundwater monitoring that is required will be proportional to the difficulty in judging:
The status of a body or group of bodies
The presence of adverse trends
The implications of errors in such judgements

4. WG 2.7 Monitoring
The design and operation of groundwater monitoring programmes should be informed by
The objectives applying to the body;
The characteristics of the groundwater body, or group of bodies;
The existing level of understanding (i.e. the confidence in the conceptual model/understanding) of the particular groundwater system;
The type, extent and range of the pressures on the body, or group of bodies;
The confidence in the assessment of risk from pressures on the body, or group of bodies; and
The level of confidence required in the assessment of risk.

5. WG 2.7 Monitoring
Further key principles
GW-Bodies may be grouped (on a scientific basis) provided that reliable assessment of each body of the status and the trends is obtained
Designing and operating integrated groundwater and surface water monitoring networks will produce cost-effective monitoring information for assessing the achievment of the objectives

6. WG 2.7 Monitoring
Best Practice and Tool Box
Conceptual model/understanding
Monitoring sites and density in relation to risk
GW monitoring in upper (recharge) zone
Examples of indicators relevant to different activities
Examples of appropriate monitoring frequency
Examples for approaches of defining monitoring frequency
Examples of quality assurance of monitoring design (sampling protocols) and data analysis

7. WG 2.8 Statistics
WG 2.8 Statistics
Results
Appropriate algorithms for data aggregation, trend and trend reversal assessment
Requirements
Statistically correct, Pragmatic
One method (different GWB sizes, site densities, all parameter types)

8. WG 2.8 Statistics
Findings – Monitoring network
Distribution of monitoring sites as well as the selected number and types of sites was highlighted as important with regard to the applicability of the proposed statistical methods and the comparability of the assessment
Minimum requirements (distribution and number of sites) depend on algorithm
Importance of continuity with regard to selected sampling sites - changes should not affect the outcome of the assessment.

9. Findings – Monitoring frequency
WG 2.8 Statistics
Findings – Monitoring frequency
Sampling frequency should be in accordance with the natural conditions of the GW-body
In the time series some observations may be missing, but the missing of two or more subsequent values should be avoided for trend assessment - risk of bias due to extrapolation
Take care of the sampling time or period to avoid bias by seasonal effects which reduces the power of the trend analyses and to avoid induced trend phenomena
In case of yearly measurements it should be guaranteed that the measurements are taken in one and the same quarter or within a certain time period of the year

10. WG 2.8 Statistics
Findings – Quality assurance
Need of sufficient information on LOD (limit of detection) and LOQ (limit of quantification)
The sampling procedure itself and chemical analysis should ensure continuity in results and comparability. (Relevant norms/standards should be applied)