During the maintenance of software systems, their architecture often degrades through processes of architectural erosion and drift. These processes are often intertwined and, as a consequence, a given module in the code becomes the locus of both erosion and drift symptoms. Architects should elaborate strategies for detecting co-occurrences of both degradation symptoms. Strategies for enabling the detection of these symptoms are based on design rules. While the specification of design rules is time-consuming, they are often similar across different software projects. In this context, the contribution of this dissertation is threefold. First, it presents TamDera, an unified domain-specific language for: (i) specifying rule-based strategies to detect both erosion and drift symptoms, and (ii) promoting the hierarchical and compositional reuse of design rules across multiple contexts. Second, a tool implementation for supporting the language usage and rule enforcement is also presented in this dissertation. Third, we evaluated the language in supporting the description and reuse of design rules on five software projects. Our evaluation revealed that architects could be benefited by using TamDera to blend and reuse rules for detecting erosion and drift occurrences in multiple scenarios.