The thesis describes the ecological conditions of six investigation sites along the river “Moedlingbach” in the city centre of Moedling, referring to the quality element macrozoobenthos. The morphological and biological conditions of four restored sections are compared with the results of highly modified sections and natural sections. The aim of the study is an evaluation of the consequences of biological engineering instruments on the macrozoobenthos biocoenose. There already exist studies concerning aspects of flood protection, flora and aesthetic factors. The consequences on the fauna of the Moedlingbach however have never been subject of a detailed study. The present thesis elevates and studies structural-ecological as well as biological parameters and evaluates the data using ECOPROF. Referring to traditional water quality and organic impact, the examined parts of the Moedlingbach show a good ecological status. Compared to the technically maintained section the restored sections clearly show an improvement of the bio-diversity and the ecological status. On the other hand, two of the four revitalised sections present negative results and, therefore, a need for action. The reasons for these negative results can be explained, above all, by the types of restructuring measures chosen. In one section, for example, the construction of a riprap pad created a water pendulum, which is atypical for this habitat and has negative consequences on the composition of the species. At another section a ‘potamization was created by the measures applied, leading to a change in the spectrum of the species.