They like to settle in areas where there is grass and an easy transition to water. If you block the access to the water with brush or perhaps some artificail barrier or temporary fence, they won't like the area as much.
Just got back from Mexico and have a lot of catching up to do but Frithguild is right on. They prefer clear escape routes to the water. The easiest thing to do is block the escape route, ideally with native vegetation. That may not be possible right now so an easy solution is to make a string fence along the shore line a few inches off the ground. All the scare tactics in the world won't work if you leave the escape route intact.
The fence idea does work - a friend from work had the same problem and he and his wife put up a fabric fence (landscaping fabric, I believe) between the water and the yard and it worked. The geese want easy access to the water for safety too (see something bad? go out in the water and it can't follow you) and if there isn't easy access they'll move on.
The only problem they had was they had to make the fence HIGH ENOUGH so that the geese couldn't SEE the water when they were on the ground - even if they never went IN the water, the sight of it would make them think it was a safe area. Their yard was fairly level, so it wasn't too hard to raise the fence a little bit.