Culvert 4 has a bootprint of tussock sedge growing right in the apron joint, which is not supposed to happen on a concrete lip that was poured in 1978. I measured the clump on 14 March: 31 cm across, seven flowering culms, roots into a seam maybe 4 mm wide. It was still there on 2 September, slightly wider, so I have started calling it the tenant.
The drainage runs about 2.4 km along the north side of Hatchet Lane, from the stock gate down to where the meadow drops into willow scrub. Eleven culverts on my stretch. I number them upstream to downstream, which annoys the parish drainage man, but I started that way in 2021 and renumbering would break every sketch I own.
Three are old clay barrels, six are corrugated steel, and two are the new plastic twin-wall pipes put in when the lane was resurfaced. The plastic ones are 300 mm and run clean. The clay ones are nearer 225 mm and silt badly at the downstream end, particularly C7, which I have measured at 60 mm of silt in the invert twice now.
Outfall plants sort themselves by how long the water sits. C2 and C3 dry out by late June and grow soft rush and creeping bent, nothing interesting. C5 stays damp all year because of a spring in the bank above it, and that outfall has marsh marigold in April, then water forget-me-not through July, then a mat of brooklime that survives the first frosts. C9 is the odd one. Its apron holds a small stand of branched bur-reed in about 90 mm of standing water, which is more than the pipe should deliver.
Flow readings are crude. I use a wooden rule painted at 10 mm intervals, held against the invert, and I write down depth and whether the water is clear, tea-coloured or grey. March gave me 55 to 80 mm across most pipes. By 20 July everything except C5 and C9 was dry or damp only. Late August rain put 40 mm back through C6 for two days and then it went again.
Cross sections get drawn in pencil on graph paper, one square to 25 mm, standing on the bank with the pad on my knee. They are not good drawings. What matters is the silt line, the water line and where the pipe has deformed, and the steel ones deform in a flattened oval that a photograph never shows properly.
Two things I want to settle before winter. Whether C9 is fed by field drainage rather than the lane, which would explain the standing water, and whether the tenant at C4 makes it through another frost. I will trench a small dye test at C9 once the water comes back, assuming the ground is soft enough to peg.
Last visit 3 September 2026. Boots still wet.