Groundwater monitoring and protection are crucial issues within the environmental policies of the European Union. European directives require to (i) identify and characterize groundwater bodies, and (ii) reach specific quantitative/qualitative standards for each identified aquifer. The Italian laws incorporate these indications and provide technical criteria to characterize groundwater bodies. In this context, strategies aimed at preventing groundwater depletion play a relevant role in the conservation of water resources. In this study, we focus on the analysis of the underlying mechanisms of natural recharge for an unconfined high-conductivity aquifer. In particular, we refer to the area of the Apennines alluvial fan of the Emilia-Romagna Region. The portion of the cones close to the Apennines consists in high-permeable deposits that extend up to several hundred meters underground. A monolayer phreatic aquifer, connected directly to the surface, is located in this area. Widespread water withdrawals are present for agricultural and industrial purposes. For this reason, the analysis of nitrate concentration in groundwater represents a crucial issue. The use of nitrogen fertilizers and spreading of sewage and sludge in the soil are considered the main sources of nitric pollution. Based on time series analysis, we investigate the natural recharge dynamics by observing the influence of hydrometric variations on the piezometry, and the relationship between water level and nitrate concentration in the aquifer. We do this by means of autoregressive moving average models. The basic idea is to represent hydrological time series as single realizations of stochastic processes. In this context, we provide a basis to estimate groundwater vulnerability through an insight on surface water-groundwater interaction, and the persistence associated with nitrate concentration in an unconfined high-conductivity aquifer.
Surface water-groundwater interaction and nitrate persistence in unconfined high-conductivity aquifers investigated via time series analysis
LAURIOLA, ILARIA;FELISA, GIADA;CIRIELLO, VALENTINA
2015
Abstract
Groundwater monitoring and protection are crucial issues within the environmental policies of the European Union. European directives require to (i) identify and characterize groundwater bodies, and (ii) reach specific quantitative/qualitative standards for each identified aquifer. The Italian laws incorporate these indications and provide technical criteria to characterize groundwater bodies. In this context, strategies aimed at preventing groundwater depletion play a relevant role in the conservation of water resources. In this study, we focus on the analysis of the underlying mechanisms of natural recharge for an unconfined high-conductivity aquifer. In particular, we refer to the area of the Apennines alluvial fan of the Emilia-Romagna Region. The portion of the cones close to the Apennines consists in high-permeable deposits that extend up to several hundred meters underground. A monolayer phreatic aquifer, connected directly to the surface, is located in this area. Widespread water withdrawals are present for agricultural and industrial purposes. For this reason, the analysis of nitrate concentration in groundwater represents a crucial issue. The use of nitrogen fertilizers and spreading of sewage and sludge in the soil are considered the main sources of nitric pollution. Based on time series analysis, we investigate the natural recharge dynamics by observing the influence of hydrometric variations on the piezometry, and the relationship between water level and nitrate concentration in the aquifer. We do this by means of autoregressive moving average models. The basic idea is to represent hydrological time series as single realizations of stochastic processes. In this context, we provide a basis to estimate groundwater vulnerability through an insight on surface water-groundwater interaction, and the persistence associated with nitrate concentration in an unconfined high-conductivity aquifer.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
