If you dream about a dam, it can mean that you are holding back strong emotions and this is causing you to feel frustrated.
You could be repressing your emotions because you are worried about what will happen if you let others know how you feel. Are you sure that hiding your feelings is not causing more harm than expressing them would?
A dream about a dam can mean that you are worried that someone else is containing their emotions and may eventually have an emotional outburst.
If you are worried about someone else losing their temper or having some other type of emotional outburst, you should ask yourself why this concerns you. Do you feel that you need to have some control over their behavior, or do you find their behavior threatening?
If you dream that you are building a dam, it can mean that you are putting up emotional defenses. You are afraid to let others get too close to you.
If a dam is bursting in your dream, you feel that you are unable to contain your emotions any longer.