For a number of decades of the 20th century there was a lot canalisation of rivers and streams in Germany. As a result of this river straightening process that was carried out between 1958 and 1963, the Selz stream was constricted between embankments and flows in a relatively meandering course through the plain between the famous rolling hills of Rhenish Hesse. In order to prevent river bed degradation and to improve both biodiversity and
flood protection, the local nature conservation association (
Selztalverband) and the district of
Mainz-Bingen managed a revitalization of the Selz over a considerable length between
Hahnheim,
Undenheim and
Sörgenloch. The loss of the
floodplain and shorter sections of river caused higher water levels and risk of flood than in the past. Some floods that nearly caused a disaster were the reason for a restoration concept. The concept includes flood protection, river bed stabilization and
renaturization measures. The main objectives are: • flood protection up to a
100-year flood • improvement of the ecological situation • stabilizing river bed/erosion control • stabilizing groundwater level Floodplains have been widened to between . Nature is allowed to develop undisturbed in biotopes, which protect and promote the
biodiversity of the landscape with its
meadows, ditches, bank slopes,
marsh areas,
wetland,
Phragmites,
willows,
hedges and boundary ridges. During the past 25 years, the village of Hahnheim has planted 27,000 trees and hedges along the Selz within its boundaries. Since the Selz renaturation project covers several miles of the Selz's riverbank, it has increased the overall length of the river. == Tributaries ==