Combined statistical techniques for the water quality analysis of a natural wetland and evaluation of the potential implementation of a FWS for the area restoration: the Torre Flavia case study, Italy

Abstract

The paper focussed on the analysis of the environmental status of a natural wetland and the assessment of potential solutions to preserve the area, the related ecosystem services and natural equilibria. Data on water quality parameters and on climatic conditions were derived from a yearly monitoring campaign and web sources respectively. Chemometric techniques and a water quality index (WQI) were applied in order to assemble the obtained information and define an exhaustive overview of the wetland status. Data processing allowed to estimate the system water balance and to evaluate spatial and temporal variations of water quality. A water deficit as well as a major wetland sensitivity respect to pollution loads was verified during the warmer season (June-September). Local criticalities and environmental pressure were assessed and possible solutions to properly manage and restore the natural system were evaluated. The use of the wetland as a free water system (FWS) receiving treated wastewater from a local UWWTP was considered in the view of using local resources and restoring the water balance, avoiding environmental impacts and excessive management costs. Wetland auto-depurative capacity was assessed through common empirical plug flow models which revealed the ammonia nitrogen loads during the winter season as the limiting conditions. By deriving the maximum capacity of the system to receive pollutants, the study showed how water balance restorations as well as environmental and economic savings are achievable. Additional benefits have to be associated to ecosystem services and the possibility for recreational, cultural and educational activities.