54 0
HISTORY OF ENGINEERING.
Rook I.
from Wisbeach , near Buekworth sluice, and extends a distance of 6.^ miles to Crabhole,from which place a natural channel 1J mile in length opens into the German Ocean atWisbeck Eye.
The excavation was commenced under Mr. Rennie ’s direction in August, 1827, whenthe old channel was closed up, and the course of the new river became deepened 12 feetand upwards by the scour of the tidal current, the sides being secured by a thick coating ofstones.
The breadth of the bottom of the river is 200 feet at the lower end, and 140 feet at theupper, near Kinderley Cut; the depth from the surface of the ground adjacent to the bedof the river is 24 feet throughout, and the width at the top varies from 200 to 800 feet.An ordinary spring tide rises 22 feet at the lower extremity, and 18 feet at Kenderley Cutjunction.
Over the channel at Suttonwash a bridge has been constructed, and an embankmentcarried across the estuary to Cross Keys in Norfolk . 1500 acres of land embanked fromthe sea are under cultivation, and 6000 more are rapidly becoming fit for the same purpose.
The water in the new channel ebbs out every day 10 feet lower than formerly, oppositethe South Holland and North Level sluices, which are outlets for UK ),000 acres of land,lying between the Nene and Welland, now efficiently drained without the aid of windmillsor steam engines.
The North Level, containing 48,000 acres, benefitted materially from this work ; a newsluice was built for the discharge of the waters into the Nene Outfall, at a level 8 feetbelow that which conveyed them into the old channel of the river. The width of thewaterway of the old sluice was only 17 feet; the new one was increased to 36 feet.
A new main drain 8 j miles in length was made from the last mentioned sluice to Clowes’Cross, 8 feet deeper, and of a capacity six tunes greater than the old one; the declivity ofthe bed is throughout 4 inches per mile.
From Clowes’ Cross the new drainage is turned into the two channels called New SouthKau, and the New Wryde, which now receive the waters from the whole of the NorthLevel.
Hie Wisbeck district contains 15000 acres, and benefits materially from the Nene Out-fall : all the drains are navigable, which was not the case with with the old ones. Thetotal expense of the Nene Outfall was 200,000/., and that of the North Level drains about150,000/.
The Nene Outfall, projected by Mr. Rennie, was completed by Mr. Telford and Sir JohnRennie ; and the scheme of the North Level drainage was entirely the work of Mr. Telford,who first made use of the natural outfall, to which no previous attention had been paid,and removed all the drains and sluices which acted as obstructions; he also returned to thebetter principle of admitting the influx and reflux of the tide; thus maintaining the channelclear by the constant scouring. The fall given in some instances is 4 inches, and in others0 inches per mile, and the banks or side slopes have a fall of 2 to 1.
A catch-water drain was executed by Mr. Rennie , for the purpose of draining theWildinore Fen, which had no outlet, and comprised upwards of 75,000 acres. The lowerpart of this fen was a watery waste, containing 15,000 acres; it is now inhabited, and itsland highly productive. The whole cost of this work was 650,000/. The wind-mills and their machinery erected by the Dutch engineer to lift the water from the lowerditches into the upper, that it might pass off to the sea, are no longer necessary, and theannual expense of maintaining them is consequently saved.
All the outfalls of the rivers of this district were affected by the tides, and particularlyby those which flowed up the Ouse : at Lynn, where the water was always thick andmuddy, a large proportion of silt was left behind. In deepening the Wisbeach river atthe beginning of the seventeenth century, beds of stones 8 or 10 feet below the then bottomwas arrived at by the workmen in sinking for a sluice, and in it were the remains of severalboats.
These stoppages must, at a very early period, have produced a most unhealthy stagna-tion of waters, and a vast deposit. On sinking the foundation of Skyrbeck Sluice, nearBoston , at a depth of 16 feet, a smith’s forge was discovered, with all the tools, horse-shoes,and various other things. The country about the monastery of Croyland is described beforeany material change was made by draining, in the history of the religious hermit who firstresided there; the writer of the life of S. Guthlake has beautifully personified all thedemons which haunt a morass; and this of Croyland must have been most abundant inwhatever could render it wretched. When the saint awoke in the dead of the night, hediscovered his wooden cell full of black troops of unclean spirits, which crept in under thedoor, and at chinks and holes, and coming in, both out of the sky, and from the earth,filled the air as it were with dark clouds. In their looks they were cruel, and of formterrible, having great heads, long necks, lean faces, pale countenances, ill-favoured beards,rough ears, wrinkled foreheads, tierce eyes, stinking mouths, teeth like horses, spitting fireout of their throats, crooked jaws, broad lips, loud voices, burnt hair, great cheeks, high