Legal and economic aspects of works to preserve the minimum vital flow rate of rivers and the water quality of receiving bodies

The quality of waterways in general and the minimum vital flow rate of rivers in particular are concepts that are subject to a broad range of interpretations. This is reflected in particular on the quantification of parameters that reduce law provisions to a series of limits to be observed. It is felt that this subject should be completely reviewed as follows: a) rather than fixing general standards, particular local contexts should be borne in mind; b) one should look in particular at the water basin as a whole — to which a given discharge or the situation of a particular waterway of a given section to be regulated refers — as a system of relations between uses and resources that should include water resource protection and the system of concessions for the public use of water; c) finally, one should move from the concept of limits to be observed to that of acceptability intervals, or rather to that of satisfying demand curves for the use of public waterway assets. The concept is well known in welfare economics and public choice literature, yet is hardly able to find a place in engineering and standards practices. The intrinsic complexity of the problem cannot always be overcome through simple solutions. In many cases these may not be effective, or at least efficient.