The drinking water system (AMGA public supply company) for UDINE city (Italy) is alimented by a freatic aquifer placed near the Torre River and a pumping field (surface 1kmq). These groundwaters and the entire drinking water system (150.000 people) are menaced by 2 problems:
1. a big decrease of piezometric levels during the summer periods (4 months/year) which forces AMGA to buy drinking water from concurrent aqueducts, paying an exagerate cost;
2. the quality of groundwaters are constantly menaced by pollution from accidental events including chemical industrial end agriculture pollution, bad human acts against strategic water ressuources.
The solution was to find the best artificial recharge works to grow the piezometric heads in the aquifer, to produce an increase of water flow pumped from AMGA aquifer, to guarantee during the summer a sufficient water supply for UDINE.
Starting from hydrogeologic numerical model for the analysys of several different options and test for calculate the recharge strategy, we found the optimal solution to build modifications in the pumping field, new hydraulic drainage works, to find the project parameters-geometry-dimensions, to find the optimized costs which eliminated all the other solutions tested by model.
The results gave:
1. type of works and governance actions to increase pumped water flow from aquifer, to increase the piezometric level and the drinking water availability during summer seasons:
2 barrages in the river, 1 artificial recharge basin;
growth of the average piezometric head in the pumping field = 0,6m;
increase of pumping flow = 120 l/s in the summer season;
cost savings on purchasing water from drinking water company competitor= 1 €/m3= 620.000€/year;
gross pay back = 5 years;
Cost = € 2,4 million.
2. type of works and governance actions to prevent groundwater pollution crisis:
installations to control the quality of water starting from the artificial recharge sources;
n.7 monitoring piezometers placed in hydrogeologic optimized positions;
arriving time of a worst possible water pollution plus intervention = 9 days;
imposed frequence and time to complete laboratory analysis sets = 9 days;
project of the alarm system h24 placed in the aqueduct UDINE center placed 20km from the pumping field;
preparation of a intervention procedure and field equipment in case of water pollution crisis/emergency (diffuse, punctual, external aggression, critical events).
3. this method can to be applied in every freatic drinking water aquifer with a recharge source available nearby.