# A Component-Based Approach to Early Warning Systems: A Theoretical Model
## 3 Results
### Requirements for Early Warning Systems  
EWSs should reflect current requirements for sustainability from the perspective of sustainable development goals [56], accuracy, integration, and complexity. Ideally, sensors and all necessary components for signal and information distribution should be powered by renewable energy sources. One possible solution is the use of solar panels or wind turbines. These renewable sources have already been applicated in many applications and have proven to be an efficient source of energy [57; 58]. However, both options present certain disadvantages. Solar panels are highly dependent on direct sunlight and receive only a small amount of energy from diffuse radiation. The biggest challenge arises during prolonged cloudy weather or winter months, when only diffuse solar radiation is available for an extended period. On the other hand, the main drawback of wind turbines is the long-term absence of wind. A suitable solution could be a combination of solar panels and wind turbines with an appropriately oversized 12 V battery. The battery must be capable of ensuring the operation of all components for at least seven days. It is common for meteorological station components, such as sensors, to be designed for 12 V batteries, eliminating the need for voltage converters. To ensure continuity and availability of information, it would also be advisable to have a backup power source from the grid where feasible and financially viable. Using renewable energy as the primary source meets sustainability requirements. Ensuring an uninterrupted dataset is one of the key quality parameters for flood prediction. Annual peak flow records are compiled, where possible, from an uninterrupted observation period. However, the periods used to select annual peak flow records may not be the same for all hydrometric stations. According to OTN ZP 3112-1:03, datasets of annual peak flows must be homogeneous. Homogeneity in this context means that the data must be selected from a period in which there was no significant human-induced influence on the hydrological regime, such as the construction of reservoirs, water diversions, or extensive river modifications [59]. By centralising multiple sensors in one location, a comprehensive monitoring system can be established. It is important to recognise that in addition to physical and chemical parameters, which ultimately reflect the destructive nature of a crisis event, various other phenomena contribute to the formation of natural hazards. These factors can be classified into:  
* Primary causes, which directly trigger a crisis event;
* Secondary causes, which influence the intensity and extent of the event. Additionally, other factors may affect the occurrence of a given hazard, such as terrain characteristics, forest cover, sediment accumulation, or infrastructure. Some of these factors are particularly difficult to assess or monitor over time. Even if they are not identified as primary or secondary causes, they may significantly influence the final manifestation of crisis events. Table 2 presents primary causes of natural hazards, as well as secondary factors that affect their intensity and extent. A categorisation of these causes was conducted to define the fundamental reasons behind their occurrence. The primary causes of floods are highlighted in a significant review by [PERSON] et al. [51], where it can be observed that floods are most often the result of excessive precipitation, frequently accompanied by storms or hurricanes, snowmelt, and, in coastal areas, high tides. Research by other authors confirms this assumption [52; 60; 61]. Secondary causes increase the intensity of floods, as they lead to soil saturation with water, reduced evapotranspiration, or high humidity affecting evaporation. In the case of droughts, the main causes include a lack of precipitation in the affected area, high temperatures leading to increased soil drying, and excessive evapotranspiration