# Evaluation of Different Simulation Methods for Analyzing Flood Scenarios in the Danube Delta
## 3 Materials and Methods
The following technical means were used for this activity: a motor boat, to the starboard side of which was fixed, with a special fastening system, a float on which the equipment for hydrological measurements was installed, an acoustic doppler current profiler (ADCP), equipped with sensors for measuring the water flow characteristic parameters, and a GPS antenna. The primary data, measured by ADCP in a cross-section through the riverbed, provided info on water depth (H), the width of the cross-section through the riverbed, measured at water surface level, water flow, and water flow velocities, measured for the entire cross section of the riverbed. Fieldwork for hydrological measurements is presented in Figure 5. Attaching the float to the starboard side of the boat was a necessary condition so that the ADCP sensors were positioned upstream of the boat's engine. Thus, the data measured by the sensors were not influenced by various parameters related to the boat engine (vibrations, currents induced by the engine propeller, the degree of attenuation of the water flow because of the impact with the boat's hull, etc.). A GPS antenna mounting system was available at the top of the sensor unit. The antenna collects geolocation data so that data recorded by the ADCP sensors was georeferenced. The main unit of the ADCP (console) was also installed on the same floater. It picked up and connected the two signal streams (transmitted by the ADCP sensors and by the GPS antenna), and, through a radio system (transmitter-receiver), communicated wirelessly with the on-board laptop. In this laptop, the control and data collection program from the main unit (console) was running. With this type of data collection, the bathymetric profiles were based on a large series of data (cross-sectional profiles were collected at average distances of about 50 m from each other and comprised a large number of points for each profile). The minimum distance measured between the cross-sectional profiles was 30 m (in critical regions or at river bends), and the maximum distance was 70 m (Figures A3 and A4). The first measured river section was on the Tulcea branch, with a length of approximately 17 km, having as a starting point Ceatal Chilia (measured transversal profile S1), and as stopping point Ceatal Stantu Gheorghe (measured transversal profile S2). Inside this river section, 340 transversal profiles were made from the left bank to the right bank of the river branch, cumulating between 160 and 250 points for each measured profile, depending on the width of the branch. Figure 5: Topo-bathymetric measurements with ADCP (acoustic doppler current profiler). The second river section was measured on the Sulina branch (the analyzed settlements are distributed along this branch) on a length of approximately 70 km, having as a starting point Ceatal Sfantu Gheorghe, and as final point the mouth of the branch into the Black Sea (the interval between the measured cross-sectional profile S2, and the measured cross-sectional profile S3). Inside river part 2--1345 cross-sectional profiles were generated, with between 110 and 200 points for each measured profile (the width of the Sulina branch being variable along its entire length).