Moved to our home about 4 years ago. We spend allot of time sorting out the house for a full renovation and neglected the garden. It was covered in bramble and dead trees. We have spend the last 12 months clearing up the bramble but noticed a small plunge pool right on the back boundary. I don't know what to do with it! Part off me thinks to back fill to level the back close to the lawn's level but am I making a mistake. Trying to add photos...