As pointed out in the surface water protection plan, approved by Marche Regional Council with administrative resolution no. 302 on February, the 29th, 2000, lower and middle Esino River valley constitutes one of the particularly compromised areas of regional water resources. The continual urbanization of territory, the incorrect management of urban wastewater, the increasing use of fertilizers and parasiticides in agriculture and above all the alteration produced by the wrong management of river areas with heavy and sometimes total destruction of the vegetation, are the basic elements of present alteration of the chemical-physical characteristics of water in our rivers. Adding to this the uncontrolled exploitation and pollution of groundwater, there is the risk of compromising irreversibly the natural status of water system so compromising the development of many anthropical activities.

In dealing with the issues of groundwater exploitation and management in a coastal aquifer, the key topic is seawater intrusion. This is defined as the salt water infiltration into an aquifer. This infiltration can be persistent or, more often, temporary. In any case, salt water takes the place of fresh water, which outflows from the system at about the same speed as the former inflows. This contemporary flow of fresh and salt water can take place both naturally through the sea and through extraction from wells. The result is increased salt groundwater and decreased fresh groundwater amounts.

At present, a large number of coastal aquifers are experiencing a seawater intrusion process. This phenomenon is induced by natural balances but increased by the exploitation of aquifers and an inordinate use of soil. The most apparent results are impoverished fresh water supplies along the coasts, where more than a half of world population is supposed to live, and, at the same time, a progressive degradation-desertification of soil. This problem is present also along Marche coasts and particularly in the coastal aquifer of Esino River underground bed and it is very important to study and quantify this phenomenon for not compromising water tapping for drinking use from the wells of the “Esino River well system ” plant managed by Multiservizi SpA.

Regrettably the problem extent is not always clearly quantifiable. This is due to the lack of data and the fact that huge amounts of water are involved. On the other hand, salt water flowing into the coast is very slow and it is necessary to wait for a long time for a balance with fresh water coming from the continent to be reached. It follows that the consequences of aquifer exploitation by man are felt when it is already too late to make something. When seawater has invaded the aquifer it would take even hundreds of years to get again to the former salt water levels.

A correct management of the problem of seawater intrusion needs first of all an in-depth knowledge of this phenomenon. It is necessary to examine the causes accelerating the process and define the feasible interventions to delay it. Particularly, it is necessary to find out the instruments to foresee the interface movement owing to the exploitation of the aquifer and natural and/or artificial recharge phenomena.