# Evaluation of Different Simulation Methods for Analyzing Flood Scenarios in the Danube Delta
## 6 Conclusions  
In the Danube Delta, floods are hydrological events that can occur at any scale, and it has been noticed that they have appeared more often in the last decades. Flooding is influenced by the rate of the Danube water level rise. Depending on their magnitude, they proportionally affect a certain part of the Delta area, and especially the settlements along the main branches of the river. From this perspective, the analysis of two different scenarios considering the breaching of the dyke for localities along the Sulina branch of the Danube River was performed in the present work. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Program Options** & **Dynamic Method** & **Static Method** \\  & **HEC-RAS** & **Global Mapper** \\ \hline Modeling 1D & Yes & No \\ Modeling 2D & Yes & No \\ Data import/export functions & Yes & Yes \\ Creating the hydraulic flow model & Yes & No \\ Creating the flow surface & Yes & Yes \\ Initial input complexity/limit conditioning & High/medium & Low/NA \\ Various ways of presenting the results & Yes & Yes \\ Interconnectivity with other software & Yes & Yes \\ Introduction of riverbed sections & Yes & No \\ Import/export GIS data & Yes & Yes \\ Appreciation of facilities/price & Yes & Yes \\ Determining the simulation time & Yes & No \\ View depths in the flooded perimeter & Yes & No \\ Introduction of the flow slope & Yes & No \\ Point spacing computation & Yes & Yes \\ Choosing interval computing & Yes & No \\ Choosing mapping output interval & Yes & No \\ Choosing hydrograph output interval & Yes & No \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Comparative analysis of the analysis methods used. The study was carried out using a dynamic method of hydraulic modeling, and a static method of GIS analysis, to identify the flooding maps for different scenarios. An important conclusion was derived from the topo-bathymetric measurements. To achieve the main purpose of this study, it was important to develop a good DTM, by improving the LIDAR model with minor river bathymetry. The digital model of the minor river bed, coupled with the digital terrain model for the Danube Delta allowed the simulation of more flooding scenarios for the localities, and considering various flooding tests. Furthermore, it can be mentioned that the results of hydraulic modeling, in case of dynamic modeling, are directly influenced by the coefficient of roughness (Manning's roughness coefficient), which in this study ranged between 0.025 and 0.03. According to [PERSON] (2018), these Manning values are specific to natural minor streams; clean, straight, full stage, no rifts, or deep pools. Furthermore, the results of the hydraulic model were validated by using real data. This revealed the effectiveness of the model in identifying areas prone to floods. The results showed that for the first breaking scenario of the dyke (the dynamic method) the flooded areas covered a smaller area than in the case of the second scenario (the static method), when the flooded zones covered a considerably larger area. The most significant differences were noticed for the localities Vulturu, Crisan, and Sulina. The results obtained also revealed the flooded surface in percentage and the expected water depth in each locality studied. The increase of the Danube levels led to a gradual increase of the flooded surface inside the localities, in the case of a breach in the dyke. The accuracy of the model simulations depends to a large extent on the accuracy of the DTM, the hydrological and hydraulic structure of the model, and the characteristics of the soil. Finally, it can be concluded that floods caused by high water levels or by dam failure can be analyzed through a combination of 1D/2D techniques or through a GIS analysis. The emphasis was on comparison of flooded surfaces resulting from the two methods. The static method used with the help of Global Mapper software does not require so much data and knowledge from the operator as the dynamic method.