Mitigation of nitrate groundwater contamination through a Forested Infiltration Area (FIA): the case study of a Nitrate Vulnerable Zone in Arborea (Sardinia, Italy) : tesi di master
Résumé
Even though nutrient export to downstream systems from agriculture is believed to be high, implementation of management plans has not been as effective as desired. The objective of this research was to evaluate the Managed Aquifer Recharge (MAR) system based on the Forested Infiltration Area (FIA) as a good practice for mitigating nitrate contamination in the sandy phreatic aquifer (SHU) of Arborea, where agricultural practices have seen an intensive input of animal effluents (slurry and manure) used to enhance soil productivity. Arborea is a reclaimed area in central-western Sardinia (Italy), defined as Nitrate Vulnerable Zone (NVZ) in 2005.
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To this end, an ante-operam monitoring phase (August 2020 to October 2021) of the groundwater and drainage water to be used for recharge was performed, and samples were monthly collected around the FIA pilot site of approximately 9 Km 2 and tested for bulk chemistry. Moreover, flow-through tests at different rates enabled the selection of the organic material for recharging the trenches of the Passive Treatment System of drainage water. The results confirmed the high nitrate concentrations in the aquifer, up to 170 mg L-1, and the effectiveness of Eucalyptus wood chips as organic material, to promote the denitrification process in the recharge water, enabling the executive design of the FIA system.These results, obtained under the MENAWARA project, are of interest for future development and long-term planning of groundwater protection management.