Oh the frustrations of mole's and gopher's. I still get irritated at how much damage they were able to create until I was able to find out the best mole eliminator. There are a ton of methods available to get rid of these rodents, but honestly I wasn't finding much success until I used a few methods "together", which really got rid of them quickly.
The best mole eliminator I found was to use multiple gopher repellent's. These included some of the following:
Poison's and chemicals are really great in that they work 24/7. With a lot of methods they are pretty labor intensive, but with the chemicals you get it out there and let the rodents do the rest. The poison's are baited so that the gopher's are attracted to them naturally. This helps a ton.
These inexpensive pieces of equipment are great to use as well. They do take a little bit of work to set up, but once you do they are good to go. I like to combine the baits and chemicals around the traps to give it more effectiveness.
If you are the type that doesn't want to kill the gopher's or moles, you may find solace in the use of non lethal options that actually work great as a mole eliminator. These devices emit an unpleasant sound underground that will naturally get the rodents to leave. They aren't as effective as the methods above, but they will work great in combination. At the very least, they will force the rodents out of their holes which will get them closer to the traps you have set up previously.
These are all great methods to use for mole and gopher repellents. I have used combinations of these with great success and they will most definitely work for you as well.