The ram pump had stopped working so I went to investigate. With all the torrential rain we had through Winter, the reservoir had completely filled up with debris washed down from the surrounding paddocks.
A bit of spadework soon sorted that out. Luckily, the filter on the end of the intake pipe (inside the reservoir) had stopped the 30 metres of drive pipe filling up with soil and grit – that would have been a much less fun job to correct.
After a couple of years of (mostly) trouble free operation, the pump is starting to get a fine coating of lime from the spring water splashes. In another few decades it might need a clean.