Reet, started small project and wondering about drainage, was just going to put some plastic tubing at the lowest point of each berm/pump and maybe fill them with rocks.
Kind of winging it but I see no reason why this shouldn’t work.

if i was to build one again, i’d cover the track in road stone and then build the pump track on top.
also i’d find something to surface it with.

mine is only ridable when its dry, local dirt is pretty much all clay 😥
may get round to rebuilding it this year as it’s ****…

Yeah it’s all a bit basic so I doubt I’ll be doing anything quite that fancy…..

my backyard track has no drainage. but i live on top of a great big chalk hill. it takes a day or so to dry out after rain.

if i lived somewhere clayey i`d try not to dig down. or to dig borrowpits around the track to avoid puddles on the track.

Unfortunately I can’t find a photo on our website, but at one PT we dug a long trench down the centre of where the PT was to be built, lined the trench with some sort of porus liner filled with rock. Fortunately we had a fall line off on one side, so the drain went to there.
Also, rather than digging down, we built up with imported material. The end result has been very good.