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

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

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

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.

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

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

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)

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.

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

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)