More than 500 thousand kilometers of river and stream water flow through Germany. Around ninety percent of it is in a mediocre or poor ecological condition. Industry and agriculture are polluting many waterways. Shipping needs have led to watercourse alterations. The Werra provides the best example of this. Discharges from potash mining and the resulting waste piles have left the river heavily contaminated with salt. Its ecosystem and species diversity are suffering. While environmental advocates and those who live near the river are fighting the pollution, the potash producer would like to massively increase the size of its waste piles and has submitted a questionable concept for protecting the river. Unlike Germany's larger rivers, which are tested regularly, little is known about how smaller waterways and streams are faring. Children and adults can now contribute to a "crowd science" campaign to test the waters near them and send in photographs and observations. More than 2500 stream assessments have been submitted and are being assessed by a scientific team. Two reporters have traced these observations. They want to find out why so many fish are dying and such a large number of animal species are threatened. What has to change to bring life back to Germany's streams and rivers? The Emscher River provides an example of how this could work. Once considered the "Sewer of the Ruhr Region," now, after three decades of rewilding and a cost greater than five billion euros, species diversity there has meanwhile recovered.