Name of a 90's sci-fi TV show about aliens?

In this TV show, aliens and humans were interbred and the most significant scene, from my childhood, was that of some of the characters chasing what they thought was a normal girl with blond hair through the forest. The chase finally culminated at the edge of a pond/lake, where several flying saucers were hovering. The girl turned around and her face was that of a 'gray' alien. Any ideas?