Willows and native plant communities were tested for their efficiency in preventing the release of toxic substances and heavy metals from the 诺儿河Ner River and its floodplain. Pilot experiments evaluating growth rate and heavy metal uptake and their effect on the groundwater level showed that phytotoremediation measures could be optimized by an ecohydrological adjustment of the vegetation to hydrological characteristics (e.g., groundwater level) of the valley. The observed difference in the growth rate and biomass yield in the first year varied twenty times depending on tested varieties (see Figure 9.11.a). This result shows how important it is to implement a careful adaptation of a plant species to local hydrological conditions in order to optimize the produced biomass yield and, consequently, income from bioenergy.