Since the devastating hundred year flood of 2002, that also hit Ruppendorf, the community has been pursuing the plan to construct a flood retention basin. In 2008 it created a flood prevention plan for the community area which already contained the retention basin at the “Langer Grund”. The planning for the retention basin started in 2010. The total costs were an estimated 810.000 Euros. Out of this, 130.000 Euros have been used for planning and 17.000 Euros for the purchase of the property. The actual constructions costs were around 640.000 Euros. For compensatory measures 20.000 Euros were considered. For these flood prevention measures the community received a 75 percent funding.

The dam is one of three retention basins which the planners of the flood prevention plan proposed to be constructed at the brooks “Langer Grundbach”, “Beerwalder Bach” and “Höckenbach”. Already the basin at the brook “Langer Grundbach” will prevent the brook in Ruppendorf and Höckendorf from going over or at least lessen it. Heavy rain or melting snow have always increased this kind of danger. In June 2013 the village was in such great danger that an evacuation of parts of the village was taken into consideration. The brook “Beerwalder Bach” had dammed up.

The start of the construction of the flood retention basin was in the late summer of 2014. The dam extends across a total of 154 meters, at the bottom 45 Meters and at the dam crest 7.50 meters. The bottom outlet that allows the brook to flow through unhinderedly at low tide, measures 50 times 50 centimeters. It cannot be closed which is why it is an unregulated retention basin. If more water arrives it is contained in the otherwise empty basin. This can contain up to 26.240 m³ of water and hence alleviate the situation at the event of a flood which statistically is supposed to occur every 20 years, not only in Ruppendorf, but also in Höckendorf and other places down the river of the “Wilde Weißeritz”. The basin was completed in the summer of 2015. Now such dangerous situations as in 2013 should occur no more.