Читать книгу Sustainable Solutions for Environmental Pollution, Volume 2 - Группа авторов - Страница 46

Like all natural systems, nature-based systems evolve over time. During the evolution of CWs, plants grow, develop, and spread, producing a biomass of increasing importance. With environment closure, the number of plant strata increases and a tendency toward afforestation is observed (climax formation). In order to conserve the purifying properties and biodiversity of CWs, management of the biomass produced and the accumulated sediments is necessary. Management measures are aimed primarily at keeping the system open and ecologically diverse. Annual operating and maintenance costs for CWs are in the range of 3% to 6% of the construction cost (Weiss et al., 2007).