Or just generate a terrain and click on the 'E' beside it, taking you into the Terrain Editor. There select a large soft edged brush and a very dark black (ie. Low elevation) shade from the little slideable range of light to dark. Have fun dabbing soft-edged dark spots all along the right side of your terrain! Try for a fairly smooth gradation between the dark and light areas, then hit the Smooth button until it's 'beach-like' and check the check mark to accept the new terrain. Back in the main window, you should now see the land sloping gently into the water. You can move the water up (Y) until you like the waterline against the shore. (By using this basic method, you won't have to tilt your terrain, which would expose the square left edge if you later decide to pull your camera back for a wider view.) Welcome to Bryce and 'Rosity, BTW! You'll no doubt see terminally confused posts from me here in the near future, since I just got Bryce 4 after using 3 for awhile!