Dog owners know that they love to dig. If you don't have a carefully tended garden, you may enjoy watching her do this, but for some people, digging can really ruin their lawns.
To control this, try cordoning off an area for your dog where you can leave her when you go out. Fill this area with fresh dirt, so she can dig all she wants without spoiling the rest of the lawn. You can put cement blocks around the area to ensure that she doesn't get out.
Over time, she will come to understand that that area is hers and she can dig to her heart's content.