The floods caused by river flooding are increasingly at the center of public attention, both due to increased cultural awareness and a more mature "risk consciousness" of settled populations, and due to the worsening state of hydrographic basins caused by the persistent absence of appropriate controls on land use in mountainous and hilly areas. Vast territories across the entire planet are increasingly exposed to the threat of such phenomena. It is easy to imagine that the perception of these catastrophes in the collective imagination is destined to increase, resulting in a burden of uncertainties and social disruptions capable of overturning the habits and customs of at-risk populations. This is particularly understandable when considering the imminence and unpredictability of these phenomena. In this context, it is evident that the prevention of emergencies related to flooding must be an absolute imperative, both from a sociopolitical perspective, involving public institutions, and from a more technical perspective, in relation to the selection and design of flood defense interventions. Regarding technical aspects, a fundamental role in the planning of hydraulic works for rivers, streams, and entire hydrographic basins is played by the monetary assessment of flood damages. In fact, it precedes the design of interventions. The study of methodologies for assessing damages from flooding constitutes a broad research field, given the diversity of scenarios that can occur. This study cannot be detached from a preliminary examination of the object of evaluation, which involves the identification of the constitutive elements of damage and the possible forms attributable to it based on their classification methods. It is from this perspective that this contribution aims to examine the principles and methods for evaluating damages to the territory caused by river flooding. The principles and methods considered have the objective of monetarily assessing damages to productive resources and environmental resources resulting from flooding.