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The Thames Walls; General View.
into what at first sight might appear to be one uniform settled plan, acted on at once and from the beginning—an idea consistent only with the exploded theory of Roman construction. That the vestiges of the old approaches have been gradually swept away, in order to make the most of the space, and in proportion as their utility was superseded by the more advanced works, has no doubt favoured the Roman theory. It is, however, impossible not to regret that so much of them, at any rate, as might provide for accidents was not allowed by common prudence to remain, in spite of the levelling and economising mania. A fracture of even a small portion of the system is a disaster the extent of which there is no foreseeing. This has been already alluded to in the way of illustration. A few facts will help out the theory. A breach of the embankment, in 1324, laid 100 acres of the valuable land between what is now St. Katharine’s docks and Shadwell under water for a year. In 1376, the whole of the lands about Dagenham, and those belonging to the Nunnery at Barking, were inundated. Some 1000 acres at Stepney were flooded in 1448. The whole of Plumstead Marshes were drowned in 1527, and not completely recovered until 1590. The entire country from Purfleet to Grays was laid under water in 1690. And even Cockney anglers can tell something about the great inbreak of 1707, which swept away 400 feet of the river wall at Dagenham, overflowed 1000 acres, and was only repaired after years of labour by Captain Perry, at an expense of 40,472l., leaving behind its mark in the shape of that little winding lake in which bream and eels so plenteously swarm.
How to keep these embankments in sufficient repair to be always ready for an extra high tide or a heavy gale of wind, is one of the most important questions affecting the agricultural interests on both sides of the river. The constant attrition of the ordinary current exercises the proverbial effect of “water for ever a-dropping;” but the lodgement of any solid body, as a drifting bit of timber, or a fragment of a wrecked barge with just enough iron about it to prevent its being carried off by the next tide, works in an incredibly short space of time amazing mischief. After two or three tides, the result is a hole in which the foreign body seems to insinuate itself with forty-auger power, and if prompt means are not taken to remove the active mischief, undermining is sure to follow speedily. It forms, therefore, a prominent and most seriously expensive part of the arrangements between landlord and tenant on the banks of the Thames, that constant vigilance should be exercised, a constant look-out kept, and injuries promptly remedied.
The general construction of the Thames embankments is what is technically called the “Earthen mound.” It consists of a heap of earth, the section of which forms a scalene triangle, with the side towards the river inclined at an angle of about 20°, and that towards the land at one of about 45°. The embankments of the continental rivers—at least away from the sea—are generally consolidated by turf carefully planted, as well as by the roots of rows of trees with which they are ornamented: nearer the sea, and in positions exposed to more severe trials, gravel, reeds, straw kept down by pieces of wood, faggots, wicker hurdles, and nets of straw ropes, are variously used for the same purpose. Nature has given the Dutchmen a lesson, and the dunes are carefully sown with the Elymus arenarius, the leaves and stalks of which are made into mats and ropes in Anglesea and the Orkneys, and the fibrous roots of which bind the sand, &c., into a sort of concrete basket-work. But the Thames embankments are fortified chiefly by tiers of stakes driven into the river face of the wall, and the intervals filled in with lumps of chalk or stone, rammed in to a level with the heads of the stakes, or “stalks,” as they are more generally called. Since, however, the steamer traffic has added its churning power to the influence of tide and wind, it has been found advisable, as at North Woolwich and the point where Barking Reach turns into Galleons, to lay down a granite pavement like that on Holborn Hill, as nothing else will stand the wear and tear.
In spite, however, of the completeness of the present system, and of the pains bestowed on its
