Building a timber retaining wall need help!

Even when he fixed the drainage years ago, it still didn't stop the water from the houses further up the hill flowing over. The neighbour was forced to make an effort, and he did, but it was fairly futile in such a storm. Being an IP, this is not something my parents saw or had to deal with until the downhill neighbour cut into the natural level rather than lift his house and then started to complain.

This downhill neighbour could easily see what you can see in the photo. The problem is coming from up the hill. Trying to force my parents to stop that deluge was silly.

When we took this house over, we did what we could to beef up the drainage on our own block. (How many uphill neighbours' water does he want us to deal with?)

The downhill neighbour has to deal with his own lack of foresight and direct what flows into his yard that our own drains cannot cope with.

This house is stumps and dirt underneath and a bit of concrete. This water doesnt' hurt anything. We sold it and the new owner may one day lift it or build under. They will have to deal with further drainage at that time. And with the house on styes that will be easy too at that time... easier than trying to dig a drainage trench between the stumps and the uphill retaining wall without undermining the stumps.