Selby Canal, Paperhouse Tunnel

Canal culvert, 1778, designed by William Jessop engineer for the Aire and Calder Navigation Company.

MATERIALS: limestone and gritstone headwalls, wing walls, waterway channel walls, and culverts, built on timber foundations.

PLAN: pair of inverted semi-circular plan walled sumps lined by headwalls with open backs and no drainage channel feeders. The sumps are linked by four culvert tunnels beneath the canal bed. The southern ends of the waterway channel walls butt up against the northern abutment walls of Paper House Bridge and splay outwards at their northern end to form a wine-glass plan.

DESCRIPTION: each sump headwall is capped by a course of gritstone blocks, stiffened by wrought-iron staples. Recesses have been cut into the inner face of the blocks to receive timber railing posts that were retained by wrought-iron straps fixed in lead. Below the capstones are three courses of large ashlar limestone blocks laid on a band of four courses of smaller blocks, which run around the circumference of the structures. Below this level (the water-level), each side or wing wall of the sump is battered by stepped stone courses, either side of a recessed vertical central panel set within the internal apex of the sump, with four 1.75m high segmental stone arch culverts at its base. The four culvert tunnels pass beneath the canal channel to the opposite sump. The west sump headwall has an up-stand with the outer surface exposed by the concrete surfaced towpath descending in a curve down to the low level of the west waterway channel wall, which is approximately 1.2m lower than the height of the parallel east waterway channel wall; the splayed northern section of the west channel wall rises back up to the same height as that of the opposite east wall and a short section of battered dry-stone retaining walling extends to retains the canal bank. The opposing splay of the eastern channel wall is terminated in a similar manner, and the canal channel between the two parallel sections of wall is approximately 5.77m wide. The open rear of both sumps is blocked by accumulations of silt and adjacent ground.