The term "coastal groove" is not a widely recognized geological term. It's possible you are referring to a specific location or feature that has a local name.

To help me understand what you're asking, could you please provide more context?

For example:

* Where did you encounter this term? (e.g., a book, a map, a website)

* What is the broader context of the information? (e.g., a description of coastal landforms, a study of erosion)

* Do you have any additional information about the feature itself? (e.g., its size, shape, formation)

With more details, I can try to help you identify the location you're looking for.