If the area is near shore, try terraforming the land up. Do be careful that it doesn't roll back down hill, maybe wrap around the area first.

Last I played, it was possible to generate more land by walking to a high ledge and hitting it with a pick. The area around the pick gets shifted to a new height, pulling down high land a little bit and pulling up the low land a LOT. It saves a ton of stone, just start high and slowly flatten the land out and to the side.