Protection structures aim to protect areas exposed to natural hazards. For instance, several clusters of check dams are located in the headwaters of a watershed, each having specific functions. Their structural, functional, and economic effectiveness must be assessed to assist decision makers in deciding on maintenance actions. Nevertheless, expert assessment generally focuses on a single check dam. It is based on the evaluation of several field indicators that are aggregated by experts. This paper aims to show how methods extracted from industry, such as dependability analysis and decision-making approaches, can be used to help formalize expert assessment with expert knowledge taken into account. For this purpose the formal methods are reviewed and their potential application introduced. This paper focuses on the use of indicators and criteria in various objective decision-making tools. For example, it compares the Analytic Hierarchic Process and the ELECTRE TRI methods to assess the functional effectiveness of a cluster of check dams.