Spring discharge and groundwater flow systems in sedimentary and ophiolitic hard rock aquifers: Experiences from Northern Apennines (Italy)

This chapter deals with hydrogeological characterization and springs/upreach streams monitoring activity on different test sites in Northern Apennines (Italy) where turbiditic and ophiolitic hard rock aquifers occur. The work aimed to define the investigation tools able to parameterize the aquifer and build-up a methodology for hydrogeological mapping. Hydrological analysis of base flow, tracer testing with fluorescent dyes and numerical flow modelling by the equivalent porous medium approach were used for the evaluation of direct recharge, quantification of flow and transport parameters and implementation of numerical models, calibrated by continuous discharge monitoring, finalized to define spring flow paths and protection areas. The ratio between direct recharge and total precipitation resulted in the range 0.13–0.17 for turbidites and 0.35–0.40 for igneous ophiolites. Groundwater average effective velocity ranges from 3.6 m/d in the thin-bedded pelitic turbidites to 39 m/d in the calcareous turbidites.