Hydrological responses and processes occurring at the outflow

The “Hydrological responses and processes occurring at the outflow” work package deals with the investigation of the the water (and the dissolved nutrients) paths from groundwater recharge areas to the springs belt, where upwelling occurs. Both discrete outflows such as springs (fontanili) or diffuse inputs to the Adda and Ticino rivers will be considered and quantified. The combined results of the three identified tasks will allow to quantify the nutrient output from groundwater, evaluate the amount transferred to the surface water compartment and identify processes occurring at the surface- groundwater interface which can affect nutrient loads (e.g. nitrification, denitrification).

Fontanili in the dry period (Photo credits: R. Balestrini)

The chemical analyses of spring water coupled to discharge measurements will provide an estimate of the amount of nutrients that is recycled back to the surface and define the quantity and quality of recently infiltrated irrigation water. The chemical monitoring of springs is not required by the Water Framework Directive (European Commission, 2000) since their basin is less than 10 km² wide. As a consequence, the available data of N concentrations are often scarce or sporadic. The situation is even worse for P, for which there are currently no data, since this parameter has only recently been listed among those to be considered in groundwater quality monitoring (European Commission, 2014). The outcomes of this WP are per se unique and extremely valuable in terms of management. They could testify for the effectiveness of mitigation measures (i.e. the limitation in the use of manure) or could suggest the need to adopt alternative or more stringent measures, targeting nutrients from both civil and agricultural sources (e.g. CSO-Combined Sewer Overflow control policy), fertilization protocols and irrigation practices. The study of river-groundwater interactions is at the leading edge of scientific research, especially because if groundwater is contaminated, its input to river system has significant ecological and social consequences, such as river eutrophication and water quality degradation.
The impact on land and water management will be evaluated by monitoring how contaminated groundwater input affects river functioning and by proving the effectiveness of mitigation measures in preserving also river ecosystem services (i.e. nutrient reduction and alternative irrigation protocols).