Google 'chipmunk swimming pool of death'. It's very cheap, works exceeding well albeit a bit cruel.
Chipmunks dig through DW's flowers, so I end up trapping a bunch the past few years. I mount a snap trap to a board, and make some modifications, adding a top, back and sides, to 'steer' the chipmunk to the front, so it is less likely that they only get caught by a leg or something. I hate to kill these things, but at least the snap done this way is fast.
But this year, they seemed to stay away from the trap. So I did a search on this bucket approach. Easy, easy, cheap (zero cost for me - we already had a bucket and the bird seed) and I've caught 6 in less than 3 days.
Just a 5 gallon bucket, ~ half filled with water, pour black sunflower seeds on the surface of the water - they float and it looks like a pile of seed. I just stacked some firewood next to the bucket, with some PB and a few more seeds. They follow the log stack and jump in. Nothing to construct, just use as is (some people get fancy with teeter-totter type ramps- but they seem to just jump in, so I don't think it's needed).
I don't like drowning versus snap, but our flower gardens were a mess. I tried talking nice to them, telling them they are free to live on our property, just don't dig up our flowers. They didn't listen. It's war.
-ERD50