We had problems with drainage of water in our backyard. Valleywoo
d told us the best way to deal with it was to dig and install a drainage pipe along the back and side of our yard, with a catchbasin to ensure water is directed into the pipe. This pipe was to divert 70% or so of the water from the back of our house to the front, where it would be brought to the surface. We wanted the exit of the pipe to be near the sidewalk so that there would be no risk of water accumulating near our house. The swale between our neighbours house and ours was to be reconstructed, and accomodate the rest of the water. In the end, the pipe exited the ground about 1 metre from the corner of our house, and a sinkhole formed due to water accumulation at that spot. The swale gets flooded with minimal rain.
We also had another swale closer to our house in which they installed pipe to attach to the pipe at the side of the house to divert water that accumulated at the foot of our deck. The catchbasin in this pipe is not even in the swale, and doesn't collect much water, making it relatively useless. Was a great idea, but not well executed.