# Evaluation of Different Simulation Methods for Analyzing Flood Scenarios in the Danube Delta
## 1 Introduction  
Although, extremely important for humanity in many respects, water also carries a significant destructive potential, causing damage to people through the occurrence of natural hazards such as floods [1]. Floods represent the most common hydrological hazard in Romania, as well as in many places all over the world [2]. Over time, floods have occurred in various regions of the country, causing particularly significant damage, both in terms of infrastructure, and in terms of households and agriculture [3]. Floods are natural phenomena that cannot be prevented. Nevertheless, some human activities (such as the increasing number of human settlements and economic assets in floodplains, as well as the reduction of natural capacities for water retention through certain land uses) together with climate change, contribute to the increased likelihood of floods and their negative impact. The study of these phenomena in the Danube Delta is important because recent flood events have increased in number and magnitude in this area, and many settlements have been affected. This river flooding triggers significant level and flow variations along the river, endangering infrastructure elements (mainly dykes of settlements), agricultural areas, and households [4]. [PERSON] [5] used the Hydrologic Engineering Center's river analysis system (HEC-RAS) to evaluate spring breakup of the ice cover which is the main agent of flooding and replenishment of the Peace-Athabasca Delta. This study showed that different ice-jam scenarios indicated that jams of moderate, rather than extreme, length were more effective in flooding the Delta. In addition, [PERSON] [6] used numerical modeling of the hydro-morphodynamics of a distributary channel of the Po River Delta (Italy) during the Spring 2009 flood event to show how the dimensions of the river plume can influence the evolution of the prodelta, while having a rather negligible effect inland, because of the major stresses induced by the high river discharge during the flood event. Another interesting study was carried out by [PERSON] [7] who evaluated the flooding of vulnerable areas by a different return period flood, by using the Hydrologic Engineering Center's river analysis system (HEC-RAS) model in the Ayeyarwady Delta Region, Myanmar. The results of this study showed that the arable land and forest were the most vulnerable to different return period flooding. The HEC-RAS software represents an affordable method for this type of assessment. According to [PERSON] [8], the acquisition, management, and use of spatial data are essential for quality of water resource studies. Thus, several geomatic methods serve hydrological modeling, and emphasizing the generation of cartographic products. Furthermore, a study developed by [PERSON] [9] on the analysis of flood modeling through innovative geomatic methods, aimed to evaluate the flood risk, while assessing the suitability of an innovative technique. The results of this study showed that the developed methodology and technology allowed for a more accurate riverbed representation. [PERSON] [10] evaluated the selected sub-elements of spatial data quality on 3D flood event modeling. The study focused on the evaluation of the state of spatial information quality. The results of the study show that the combination of different type of the input data, like a digital relief model combined with geodetic or topographical data, can provide a redefined 3D model. This type of input data influences directly the hydrodynamic modeling process. In the Danube Delta, floods are hydrological events that can occur at any scale. These phenomena have appeared more and more often in the last decades. Due to the geographical position, and the specifics of the area, as well as the unique natural character of the Danube Delta, hydrological hazards (heavy showers, sometimes accompanied by hail, river flooding, strong storms, extreme temperatures, etc.) frequently arise [11]. The flooding process is influenced by the rate of the Danube water level rise.