REWT
Rivers of England and Wales, Temporally
The Somerset Levels
The other landscape rebuilt wholesale, and the one where the scoping exercise’s terrain model was silently wrong for a month.
Research leads, not verified citations, except where marked verified.
Why this region is difficult
The Levels are a coastal wetland reclaimed in stages from the Roman period onward, with medieval monastic drainage — Glastonbury, Athelney, Muchelney — followed by piecemeal enclosure and then by statutory schemes.
Unlike the Fens, a good deal of the medieval work is still in the network. Some rhynes are older than they look, and generic pattern rules that date a channel by its name are weakest here for exactly that reason: in the Levels and Romney Marsh a sewer is a drainage channel, and many have medieval origins even where the present cut is later.
And the terrain model here was silently wrong. The region box marking untrustworthy terrain had been typed with the wrong easting — 200 km out, landing in open sea off Cornwall — so every reach on the Levels read as trustworthy terrain, on precisely the pumped and embanked ground the flag exists to mark. Corrected, the Brue reads 0.937 untrusted and King’s Sedgemoor Drain 0.487. Nothing in any national total showed the error, which is the standing lesson of this project rather than an anecdote about a typo.
The schemes, and when
| period | scheme | effect |
|---|---|---|
| Roman | coastal embankment and early reclamation | |
| 12th–15th c. | monastic drainage by Glastonbury, Athelney, Muchelney | rhynes and river diversions, some still in the network |
| c.1200s | the River Brue diversion to Highbridge | a medieval re-routing, not a modern one |
| 17th–18th c. | piecemeal enclosure drainage | |
| 1795 | King’s Sedgemoor Drain | a major new channel |
| 19th c. | Huntspill and Brue improvements; pumping | |
| 1940 | the Huntspill River | wholly modern |
Modern scholarship and survey
- Williams, The Draining of the Somerset Levels (1970) — verified, and the standard account.
- Rippon, The Transformation of Coastal Wetlands (2000) — verified; the comparative study of wetland reclamation, and the best guide to what is medieval here.
- Rippon on the Brue valley, and the Somerset Levels Project (Coles) — the wetland survey tradition that produced the Sweet Track, and with it a great deal of palaeoenvironmental work on where the water was.
Cartographic and land-record
- Monastic cartularies and estate records, for Glastonbury in particular: the drainage was carried out by a landowner who kept archives, and the surveys survive.
- Enclosure awards, 18th–19th c., which frequently record the older watercourse as a boundary.
- Day and Masters’ Somerset (1782) and the county maps before the OS.
What to do here first
Establish which rhynes are medieval. The generic pattern rules cannot, and are admitted to be weak. This is a case where a local study answers a question the national method cannot — and where getting it wrong is invisible: a medieval rhyne dated 1600 is silently removed from the reconstruction, and nothing in any total will show it.