I have a 5 foot wide concrete side-walk running next to my house. I want to cut a 2 inch groove from the wall to the yard in order to run a PVC irrigation pipe from the faucet on the wall to the trees. The primary question is:
What is the easiest way to cut that groove into the side-walk? (i.e. what tool will I need and how do I use it?)
Other questions:
Can you think of a better way to run irrigation from the faucet (that you see further down the wall) into the garden?
What other problems am I going to run into and how can they be avoided?

