CHAPTER X.
THE AUTHOR’S PLAN FOR EVENTUALLY COUNTERACTING THE INJURIOUS EFFECTS OF THE GERMAN OCEAN ALONG THE EASTERN COAST OF NORFOLK, COMPRISED WITHIN A DISTANCE OF THIRTY MILES, EXTENDING FROM WINTERTON-NESS TO OR A LITTLE BEYOND CROMER.—A PLAN FOR THE ERECTION OF JETTIES SUBMITTED, &C.
THE knowledge gained upon this interesting subject, the instances adverted to in the former chapter, prove almost beyond a doubt, that the question—Whether art can arrest the progress of the German Ocean along the Norfolk coast? may be answered in the affirmative.
The first and greatest desideratum necessary to be obtained is a bold shore, formed by a legitimate beach, a term applied by the eminent engineer, previously alluded to, who stated its ascent should be three inches and a half in the yard, which would realize seventeen feet and a half in two hundred and ten yards; a height which no sea upon this coast could ever reach.
From there being plenty of materials in the offing, the ascent could be more gradual, which would be preferable, for a two-fold object must be kept in view; the one, for the preservation of the lands in the interior; the other, for the safety of mariners, should misfortune attend and compel them to run their vessel ashore. Besides the more abruptly a body presents itself, whether natural or artificial, to the almost irresistible force of the tidal wave, when called into excessive action, the less it is likely to remain stable and compact. It will therefore be necessary to ascertain the extent of the shoals existing in the offing, and the elevation likely to be realized may easily be calculated.
A single row of piles driven into the beach at right angles to the shore, wherever a shallow exists, will be sufficient, with plank fastened to them, to encourage the materials, brought by the tidal wave and current, to be retained and lodged against them. The length of the piles necessary, must depend upon the supposed elevation required, taking into consideration, not only the depth of the sand lying at the bottom of the shallow, but also the strata beneath. In a very short time, by gradually adding the plank, the shallow will become filled up, and the tidal wave will pass over without disturbing its surface, the same plan must be adopted wherever a shallow exists at low water mark, but possibly the difficulty of applying the plank in that situation cannot be so easily accomplished; consequently a greater number of piles will be required, as they must be inserted near to each other.
After a shallow has been filled to the level of the beach then existing, and the upper part of the pile still projecting, let plank, if necessary, be gradually added about one or two feet in breadth at a time, as the deposition accumulates.
Proceeding onwards into the sea as opportunity offers, some portion of the shoals will be removed into the shallows; another, probably, will be carried towards the cliffs. To facilitate this object, let a long tined harrow be fastened to the stern of a boat, which being urged by men, will loosen the materials on the surface of a shoal; and the flowing of the water will carry them, if the wind is in a favourable quarter, towards the shore, and thus will the beach become a consolidated body, with superabundant materials deposited at high water mark: these of course must be removed towards the cliffs. If the materials consist principally of sand, a plough might be employed with considerable advantage, turning the furrows inward towards the cliffs; on the contrary, should stones predominate, they must be deposited at the base of the cliffs. Easterly winds will remove the loose dry sand towards and fill up the spaces between them. Many suggestions, however, to expedite the work will present themselves upon inspection and trial. {70}
The distance required from one row of piles to another must also depend upon circumstances. Wherever the sea reaches in, should a shallow or flat exist, there piles will be necessary, as well as to the southward of it, which will greatly accelerate the deposition of materials where they are so much required.
[Picture: The breakwater, shewing the supposed elevation of the beach from the deposit of sand. D. Hodgson, delt. C. Graf, Lith. to Her Majesty]
Discrimination will also be necessary in the application of the piles; for a minute and continuous observer will perceive it frequently happens, the alteration of a current and the wind favouring it, the sea will reach in towards the cliffs, and undermine and excavate one locality, while another, previously visited, will become filled up by materials dislodged from the former place. {71} In the latter instance, piles will not be required to be applied immediately, for probably some of the materials, irregularly accumulated, will be requisite to be shifted to their former situation. Hence the reason of applying piles to the southward and not to the northward of a locality requiring immediate assistance.
Again, considerable difference in the insertion of the piles must be made according to the contour the beach presents; between a distance continuously flat, and a shallow that only requires to be filled up. In the latter a few piles inserted from west to east, will answer extremely well; in the former, an opposite direction must be pursued; that is, from the north-west to the south-east, according to the accompanying plate, for the sweep of the water must be taken into consideration, and also the necessity for encouraging sea-beach materials to accumulate to the southward of a groin, as well as to the northward. Upon this our final success depends.
While the above plan presents the least resistance to the tidal wave when most agitated, the tidal current will be checked and rendered powerless, and the gradual elevation, from the deposition of materials, will produce the effects exhibited by the breaking of the waves on a shelving shore; and, as they roll onwards, their power will become diminished, by wanting weight and depth to aid their motion.
In several places on this beach, the sand, shingle, &c., do not exceed four feet in depth, and in some instances are still shallower; thus at Cromer, a large body of calcareous deposition exists, and projects above the beach at low water mark; but between that and the cliffs, now temporarily protected by a sea wall, a shallow or cavity of considerable length and depth must have existed: this induced the inhabitants, who had witnessed the good the jetty had effected (previous to the injury Cromer sustained, and alluded to in a former chapter), to insert a groin immediately to the southward, or rather westward, of the town, eighty-four yards in length.
The shallow or cavity became filled up to the top of the groin, and a quantity of sea-beach material, consisting principally of sand, seemed disposed to accumulate against the base of the walls in June, 1844, but unfortunately the groin was not sufficiently extended towards the sea; the piles, instead of projecting above, did not equal in height the mound alluded to, and consequently it is not so efficacious as it would otherwise have been.
The jetty too has some influence towards prohibiting a still further proof of the efficacy of this groin, at least along shore to the northward, or rather eastward; for rude in construction, it is ill calculated to effect a twofold object, which ought to arise from it. The platform resting upon piles of huge dimensions in height and diameter, appears to have been one continuous length, from the base of the cliffs to the elevated rock at low water mark. Its considerable altitude above the surface of the beach, its unwieldy structure, from the timbers employed, and above all, its extent towards the sea being limited, accounts for its partial destruction in the storm alluded to. The dashing of the waves against the piles, even in calm weather, gives an impetus to the water at their base, and produces eddies or whirlpools, which prevent sea-beach materials accumulating in the immediate vicinity.
The inhabitants, however, appear so far to have been aware of this circumstance, that in repairing the jetty, they had recourse to iron stanchions, presenting a flat surface towards the sea; but the same impediment to utility still exists.
Let us now consider whether a jetty could not be constructed to afford not only a delightful promenade, the necessary appendage to a frequented watering place, but the retention of sea-beach materials, and the consequent elevation of the beach.
For this purpose let wooden piles of English oak be employed, of requisite length to enter the solid strata beneath the surface of the beach. The extremity for insertion must be pointed and shod with iron, and the opposite end must be protected with a rim of the same material, which ought to project above each pile, so as to leave a cavity sufficiently deep to receive the one end of an iron pillar, about eight or more inches in diameter, if considered necessary; and the length of this iron pillar being determined, its upper part can be readily formed to support the wooden plank constituting the platform of the jetty, to which it can be fastened. Now, if the piles are inserted into the beach in a continuous range towards the sea, leaving a space between each pillar, from two to three feet apart, it may readily be inferred, that the desirable object will be realized, and a permanent good will be obtained. The expense, in the first instance, will of course be considerable, but its durability and usefulness ought to supersede such an obstacle.
It is a source of congratulation to observe considerable economy in the expenditure which so great an undertaking requires, can be effected by using, in a general way, the Pinus Sylvestris, or red fir, grown in the neighbouring plantations; {74} these, if taken down in the winter months, trimming them, and depositing them in the sea, in readiness for insertion as opportunity suits, will retain their resinous properties in the greatest abundance, and prevent the exudation, which an exposure to the spring and summer months would inevitably produce. Upon the resin they contain their toughness depends, and by adopting the above plan, and using those small in diameter, the instrument necessary for propelling them into the beach, will not disturb the surface of the pile most exposed to its influence. The following instance will prove their durability, and that a careful insertion of the piles is only necessary to render their stability certain, even if extraordinary gales should cause the legitimate beach to be disturbed.
At Mundsley, several years ago, not within the memory of the oldest inhabitant, some fishermen drove four piles, six inches in diameter, into the beach, between high and low water mark, for the purpose of forming what is termed a coy, for containing lobsters caught at sea, until an opportunity for their disposal occurred. To the piles were attached some boards, so as to form a square, within which was placed a box for their reception; and a piece of wood, fastened upon the top, prevented the box from being disturbed by the water. At length, however, it became disused, the boards attached to the piles gave way, but the latter still remain firmly imbedded in the strata beneath, and their tops are only visible when north and north-west winds prevail, the sand lying around, above, and between them being then removed.
The shipowner, and above all the hardy sailor, cannot but rejoice at the prospect of obtaining a broad beach upon an inclined plane, for should a vessel be driven on in ever so heavy a gale, instead of having to contend with the cheerless prospect now before them, rendered not only formidable, but terrible, from the numerous shoals existing on this coast, there would be only one, and the vessel would arrive at its destination in a more gradual manner; her keel would become almost immediately impacted in the sand to such an extent, as to render her steady; for the waves having to attain an ascent, would be checked in their career, and for want of depth, would neither be able to injure the vessel nor destroy the mariner: hitherto, the great power they possess has, in many instances, dashed the former to pieces after she had struck the beach, and the latter has been hurled towards it, either too suddenly, or by their rebounding, swept into the depths below; while he, poor creature, so long as consciousness or presence of mind exists, uses his feeble efforts to reach the blessed shore, but, alas! too frequently in vain; he either sinks, to be wafted to another, a lifeless, mangled corpse, or arrives too late to be saved, even if the vibration of the heart exists, for want of proper accommodation and attention. If a legitimate beach could be once formed, a little exertion and assistance from those on shore, would be able to rescue him from the now almost inevitable destruction.