**4. Discussion**

#### *4.1. Discussion of the Applied Methods*

For effective planning and implementing of measures to increase the resilience of water supply systems, it is necessary to assess the status of emergency preparedness. The Emergency Preparedness Planning Indicator was developed to increase transparency by quantifying this assessment. The EPP was tested on the basis of the case study for its applicability and significance. The determination of the status of emergency preparedness planning was implemented by means of a data set of the research project NoWa I which is representative for Germany.

The composite indicator developed in this study enables a measurable assessment of the status of emergency preparedness planning. The main and sub indicators included are based on scientific publications (e.g., [12,14,17,23]), so that they reflect the current state of research on emergency preparedness planning. The development and application of the composite indicator is based on two main motivations. Firstly, the indicator can serve as a tool for self-assessment of emergency preparedness planning by asking specific questions. The self-assessment can be used by water utilities, regional or national authorities and municipalities to improve the prevention measures. The result of the indicator can also raise awareness of the relevance of emergency preparedness planning and show the need for action.

Secondly, the indicator supports local and regional authorities as well as national and international organisations in the assessment process, by comparing different municipalities, e.g., in the context of benchmarking processes of water supply systems. The results should support these institutions in decision-making, e.g., on the allocation of resources, and make them more transparent and consistent.

Two weighting methods were used to determine the emergency preparedness planning indicator. An equally distributed weighting of indicators is the standard assumption in the literature (e.g., [40,41]). If equal weightings are used, the indicators are either constructed in such a way that each variable or branch of a hierarchy level is equally weighted. To determine the EPP, equal weighting was applied to each hierarchical level. Furthermore, a weighting of the main and sub-indicators was applied based on expert knowledge. However, no strict participatory method has been applied here, where all weightings included are based on expert opinion [39]. This was only used for the weighting of the main and sub-indicators, but not for the individual indicators. For the individual indicators, aggregation at each level by arithmetic means was applied. Due to the different number of partial and individual

indicators, they have a different weight despite their apparent equal weighting [42]. This also applies to the evaluated data set of the NoWa I project and must be taken into account when deriving the need for action.

The results show only minor differences with the two different weighting methods, both for the data set of the NoWa I project and the case study. Consequently the experts' opinions confirm the relevance of all five process steps of risk and crisis managemen<sup>t</sup> according to [13,14]. In order to increase the acceptance of the indicator and to simplify the calculation, it is therefore recommended that the weighting be applied by using statistically equally distributed weights.

#### *4.2. Discussion of the Indicator and Assessment Results*

The results of the status of emergency preparedness planning for the case study show that some measures have already been implemented. An advanced state of implementation can be seen, particularly in the preliminary planning (1) and preventive measures (3). However, since the status of the risk analysis (2) still needs to be improved, the appropriate identification and implementation of preventive measures cannot be in a targeted manner. For this reason, the evaluation of the preventive measures (3) is necessary following the complete implementation of the risk analysis (2). Further action is needed in the area of crisis managemen<sup>t</sup> (4). The sub-indicator results of this process step refer to the lowest level of implementation in the case study. However, since the crisis managemen<sup>t</sup> (4) measures are based on the risk analysis (2) and the preventive measures (3), the implementation of a systematic approach step-by-step is an important prerequisite. Nevertheless, the individual process steps must still be evaluated and updated regularly.

The results of the composite indicator show a very heterogeneous picture with regard to the implementation status of emergency preparedness planning in the German water supply sector. The heterogeneity of the emergency preparedness planning indicator exists both in the districts and at the municipal level. Furthermore, the results of the respective five process steps are very diverse. Thus, some aspects of emergency preparedness planning have already been implemented. Nevertheless, implementation is still insufficient in some districts and municipalities.

The differentiation of districts or municipalities according to their number of inhabitants indicates that in both cases, larger municipalities have on average better emergency preparedness planning than smaller ones. Nevertheless, both groups contain outliers in both directions. Reasons for a more sophisticated emergency preparedness planning in larger municipalities may be, on the one hand, an extensive staffing or optimized structural conditions. On the other hand, the water supply in larger municipalities in Germany often lies in the responsibility of larger supply utilities, which often devote themselves more intensively to this task due to their corporate structure.

Indicator methods can reduce their usefulness for policy-makers or even lead to disadvantageous decision-making due to over-simplification of complex concepts and the use of aggregation procedures that are difficult to understand [43]. Although the answers to the questions used to determine the EPP are checklist-based self-assessments, the scope of the questions could lead to little attention being paid to the individual answers. The result of the case study shows that the procedure is applicable and the self-assessment questionnaire with 74 questions is appropriate. A shorter list of questions would lead to a less meaningful result.

The emergency preparedness planning indicator enables a quantitative comparison between municipalities or water supply utilities as well as the five process steps and the identification of the need for action. In the German water supply sector, the implementation of risk analysis should be emphasized. Preventive measures that have already been taken have to be checked for their appropriateness following the successful implementation of a risk analysis. Threshold values for sufficient or improvable emergency preparedness planning have to be defined. However, this cannot be achieved by science alone. This requires in particular a discourse between scientists, technical experts and political decision-makers.
