Source: The Great Interpretation of Dreams (Ibn Sirin)
A dam in a dream is an impenetrable man who keeps secrets. It indicates a just ruler. Its collapse indicates the death of the ruler.
Source: Perfuming Humanity in the Expression of Dreams (Al-Nabulsi)
A dam indicates knowledge and religion that prevents strife. Building it indicates a good deed.
Source: Signs in the Science of Expressions (Ibn Shaheen)
A dam is interpreted as the king. Its strength is the king's strength, and its weakness is the king's weakness.