Deleting shoreline

I am modifing Haines Airport (PAHN) to make it look more realistic, by moving the shoreline. I have sucessfully moved the water, but I cant seem to cover up the origional shore with water.
I am using Scenery Builder, but I wont mind downloading others.
Here are some pics
[glb]Before[/glb]

[glb]After[/glb]

Thanks for any help!
SHV*0151
I am using Scenery Builder, but I wont mind downloading others.

Here are some pics
[glb]Before[/glb]

[glb]After[/glb]

Thanks for any help!

SHV*0151