The development of a large city regions has a noticeable dependence of a local ecological situation. To motivate their stable growth and to create human-friendly environment the technologies of nature regeneration is needed. One of the approaches available is the implementation of hinged water modular systems containing a filtering higher plants. Among the practical consequences of this method – the prevention of water flowering that is especially useful for in-city reservoirs. The paper presented is devoted to investigation of a stepped mesh structure of this type that holds a plantings of water hyacinth. The macromorphological characteristics of the colonies attached to the assessment of nitrogen-transforming biocenosis according to the total index of species diversity were studied. The results show that the redox capacity reserves of phytostructure biomodules are more than 40% while the nitrification efficiency is about 90%. In addition to plant adsorption effect the increased formation of activated sludge takes place. The concept allows to start an effective exploitation immediately after the placement and leads to significant financial economy after the first year of using. In general, the approach presented is easily adaptable and can be used for most of the existing in-city water reservoirs.