Most of my career was on water. After eighteen years with Otorohanga District Council operating a 12 tonne digger, I moved across to Water Services for another thirteen. Picked up a National Certificate in Water Treatment and Reticulation while I was there. Drainage is not something I picked up on the side, it is where I spent half my working life.
Now I run the same kind of work on a smaller scale: residential drainage, water-table maintenance, stormwater rework around houses and small sections.
A lot of drainage work happens close to the house, close to fences, in back yards, in tight spots. A 12 tonner cannot reach half of it without taking out fences or compacting clay across the lawn. The 1.8 tonne gets in there, cuts the trench you need, and leaves the rest of the section alone.
The certificate is not a marketing badge, it is why I know what to lay, what slope to lay it at, and what mistakes to avoid. If you are not sure what your section actually needs, ring me and we walk through it.