In general, the most favourable conditions were achieved at an average groundwater level lower than 0.4 measured from the ground level, while the growth rate at the initial stage depended on shallow and stable water levels. On the other hand, the efficiency of the phytoremediation process depended on heavy metals availability for plants and increased in anoxic conditions of high groundwater levels. Therefore, the remediation potential was determined by a combination of the growth rate and the availability of heavy metals to plants (see Figure 9.11.b). The regulation of groundwater levels or the selection of proper plant communities may be then a tool for optimizing plantation efficiency for either remediation of bioenergy production. Using native plant communities can help in the restoration of biodiversity and ecological values of the river and its valley.