There may be locations where water leaving a trail surface erodes a channel into the batter. This needs to be permanently addressed before serious issues arise (ideally when the channel is about 40cm deep).
The process is as follows:
1. Identify the existing water path. This should remain unchanged, as the new drain will be in the same location as the current channel.
2. Widen/tidy the channel to create a more uniform drain. Careful attention should be paid to the drain entrance, to ensure it effectively captures and funnels water.
3. Line the drain with geofabric.
4. Use rocks to line the geofabric, stacked to encourage water towards the center of the drain (and prevent water from escaping the drain).
5. Use available excavated materials to bolster stacked rocks.