In this paper the development, construction and use of a rainfall simulator (RS-TUHH) are described. On a testing area of 1m² different drop forming measures have been analysed before the simulator was constructed. The RS-TUHH uses ending grid heads with a grid space of 6 cm and an underlying drop splitting net. The simulator consists of four parts: the pipe pressure and water distribution module, the aluminum structure, the irrigation system and the drop splitting net. As it is built, the shaped plot area of 6 m² can be divided in to 3 sectors á 2 m². The main intention is to imitate natural rainfall by reproducing parameters like rainfall velocity, intensity and duration, as well as drop size, amount and distribution. Experimental parameters are measured with laser precipitation monitor (by ThiesClima) and rain collectors. The RS-TUHH is able to imitate natural heavy rain events of different intensities from 3 to 200 mm/h on three sizes of plot areas with any duration. Intensity and duration are set by the control module. Drop size distribution and drop amount depend on the used net grid space. Spatial distribution is homogeneous over the plot area. Fall velocities are low compared to natural rain.
