I had this problem once. Instead of putting the sprinkler on to water the lawn, I put the hose down the biggest molehole for about twenty minutes. Then the same for the next biggest hole. The moles stayed away for ages. Mind you, I think after about a year they learned to swim.
We have molehills I'm always happy when I see them because moles are fabulous, plus it makes your garden interesting if you have your own little mountain range :)
One suggestion is to ask them to leave and go live somewhere else. This method is rated by some as simple but very effective, provided, of course, it is said with real feeling!!