In a heavy saucepan, melt the butter over low heat.

Add the flour and stir until the mixture is smooth.

Cook for 1 minute, stirring constantly.

Gradually add the chicken broth and cook over medium heat, stirring constantly, until the mixture thickens.

Stir in the half-and-half, fresh lump crabmeat, drained whole kernel corn, salt, garlic powder, and pepper.

Cover and reduce the heat, simmering for 20 minutes.