On the Use of Fascines in the Public Works Of
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158 OTHERSELECTED PAJ?ERS No. 1,415.-“ On the Use of Fascinesin the Public Works of Holland.” By THOMASCOLCLOUGH WATSON, M. Inst. C.E. HOLLAND,from its geographical position, is exposed bothto damage from the sea and to internal inundation. Lying at the outlet of the rivers Rhine and Meuse, for a great part many feet below low water, the inhabitants have been engaged for centuries in a continued contest withthe waters. In this struggle the Dutch have had to contend with no ordinary difficulties : their country produces no stone, timber, or other material usually employed in great hydraulic works; while the soil is composed of soft alluvium, broughtdown by the rivers, and deposited on abase of sand which formed originally the bed of the ocean. While Holland produces none of the materials referred to, its swamps and morasses are admirably suited to the growth of the willow, alder, aspen, and brushwood of analogous character. This has been taken advantage of; hence nearly all the vast protective works of thecountry derive their strength from the judicious employment of fascines. The object of this Paper is to show how, withtheir aid, the Dutch have succeeded inprotecting their country, not only from internal inundation, but from the ravages of the ocean itself. FASCINES, Called in Dutch ‘ Ryshout,’ are derived from copses of willows, osiers, &C., on the low lands and islands in the estuaries of the Rhine and the Meuse. Willow, with a small admixtureof ash and alder, is grown as a business, the crop being cut every third or fourth year.l The wood is cut early in the autumn as a rule, but in cases of extraordinary demand in the spring. The cutters are careful to leave the stub, or root, with an oblique upper surface, having its highest point towards the north; neglect of this pre- caution is said greatly to lessen the succeeding crop. There are several sorts of ryshout: Hollandsche, Brabantsche, Geldersche, Limburgsche, Schornesche, andGasterlandsche, so 1 A hectare (24 acres) will produce about four thousand to five thousand bundles of fasines, be3ides stakes and hoop wood. Downloaded by [ University of Sussex] on [14/09/16]. Copyright © ICE Publishing, all rights reserved. FASCINE WORK IX HOLLAND. 159 calledfrom the different provinces wherethe wood isgrown. Fascines of oak and hazel are procured from the higher districts, but the wood generally used is willow. ‘ Hollandsche ryshout ’ is of this latter wood, very full of small branches and twigs, the main sticks growing tolerably straight and parallel. The largest are used for cask-hoops ; the smaller are cutand tied in bundles. Each bundle contains at least three sticks 9 feet 10 inches to 11 feet 6 inches long, and two of 6 feet 7 inchesto 8 feet 2 inches;the twigs and smaller branches remainingattached to the sticks,which areabout 1;: inch in diameter at the root end. If the branches are insufficient, more brushwood is added ; the whole is bound round with two osiers, one beingabout 1 foot from thethick end, theother 3 feet from the top ; the bundle, when complete, should measure about 17 inches in circumference at the thick end, and about 14 inches at the other.These faggots form thegreat base of all fascine operations; and their cost is from 5s. to 7s. per hundred accord- ing to demand. Fascines should beused within a year of their being cut ; if kept longer they lose much of their strength and toughness. ‘ Raring band,’ or ‘ Tuin latten,’ are sticks of about 2 to l inch in diameter, without twigs or branches, made up in bundles of twenty-five;they are straight, tough willow, and their cost is from 228. to 30s. per hundred bundles. ‘ Hollandsche garden,’or latten, resemble the former, except that the branches are allowed to remain ; they are thinner and longer -8 feet 10 inches to 9 feet 10 inches-made up in bundles of forty each, secured by osiers. L Wiepbanden,’ ‘ Kruisbanden,’ and L Enypbanden,’ are osiers to be used as withes or binders; they are respectively 4 feet 3 inches, 5 feet 3 inches, and 6 feet 7 inches long, and their cost is from 38. to 6s. per thousand. L Palen,’ or L Staken,’ are stakes of willow or alder, about 6 inches in circumference in the middle, 4 feet 5 inches long, and have a sharp three-cornered point; these are made up in bundles, con- taining ten each, at 24s. to 30s. per hundred bundles. ‘ Slieten are heavier stakes than theforegoing, being 7 inches in circumference, and 7 feet 3 inches long. ‘Dyk horden ’ are close wattled hurdles, consisting of thirteen vertical equidistant stakes, interwoven with pliable willow sticks about 3 inch in diameter. The above completes the list of Hollandsche‘ryshout ’; that derived from other provinces is of much the same description, dif- Downloaded by [ University of Sussex] on [14/09/16]. Copyright © ICE Publishing, all rights reserved. 160 PAPERS.SELECTED OTHER fering only in an admixture of oak, hazel, ash, and other brush- wood. Oak piles, called ' Perkoen palen,' are also used in fascine works ; they are about 5 feet 3 inches long, and 1 foot in circumference in the middle. Two sorts of reeds are used in protecting slopes from the wash of water under fascines : L Groenriet,' cut when green, called also ' Bladriet,' made into bundles 8 feet 2 inches long and 2 feet in circumference ; and L Dekriet,' cut when come to maturity, made up into bundles 6 feet 7 inches to 9 feet 10 inches long, and 3 feet 3 inches in circumference. The materials above described are all produced in the country ; but as large quantities of stone are required on nearly all fascine works, either as ballast to submerge the fascine mattrasses, or as paving onslopes permanently exposed to wash, basalt from the Rhine is chiefly used, while Norwegian granite and Belgian lime- stone are also employed. HOW THE FOREGOING MATERIALSARE XADE USE OF. The duties of the Dutch engineers, so far as protective works are concerned, consist mainly in constructing, with the foregoing materials, dams to restrain rivers within certain channels ; to pro- tect slopes or foreshores; todam off river branches,or tidal estuaries, and to reclaim land. As an instance of the latter, the following description is given of the mode adopted in closing an estuary of the Zuiderzee, east of Amsterdam, called ' Het Y,' under the Author's supervision :-The width at the point selected for the construction of the dam was 1,367 yards, about Q mile ; the depth of water varying from 5 feet to 27 feet. The bottom was soft alluvium, about 40 feet deep, reposing on sand.There was a rise and fall of tide of about 14 inches ; but variations in level from storms reached 10 feet to 15 feet, at which times the current was 23 miles per hour, alt.hough USIK~I'JInot more than half that velocity. At 328 yards from the northern end,locks and sluices were constructed in the body of the dam, taking up about 394 feet of its length. A transverse section of the dam is represented in Plate 11, Figs. 1 and 2. The following is an extract from the specification : " The crown of the dam is to be 13. '1. feet broad, rounded 9 * 8 inches, carried to 12.3 feet above A.P. (Government standard level, called Amsterdamsche Peil,being .the datum of reference all over the Netherlands) ; the external slope facing the sea to be 3&to 1 to 1 * 64 foot abpve A.P., and the internal slope to be 2 to 1 to the same level ; then a horizontal berm 9 - 8 feet wide Downloaded by [ University of Sussex] on [14/09/16]. Copyright © ICE Publishing, all rights reserved. FABCINE WORK IN HOLLAND 161 on the outside, and another 16.4 feet wide on the inside, and next slopes of 2 to 1 to 1.64 below A.P. : if fascines are used, slopeg below this level to be jy to 1. “.The slopes, berms, and crown are to be covered with puddled clay 3 * 28 feet thick ; both sides .to be protected with strong fascine works from the top to 1 64 foot below A.P., and loaded with stone. When the dam is closed, the fascines on the inside and outside slopes are to be removed ; a bed of broken bricks, 0.66 foot thick, is to be placed on both slopes, and the surfaces paved to 1 e64 foot below A.P., with stone at least 1 foot thick.” In commencing the construction of the dam (dyke, in Dutch), the first step was to cover the entire site with a strong fascine mattrass, worked in pieces 197 feet long,and overlapping each other about 3 feet 3 inches, called ‘ grondstukken ’; then to build up the exterior dams entirely of fascines to low-water level, nearly filling the trough orhollow between them with sand or clay. As fascines underwater are nearly always used in the form of ‘ grondstukken ’ or ‘zinkstukken,’ a detailed account of their construction is necessary. The first requisites for a ‘grondstuk’ are the ‘ wiepen ’ (Plate 12) ; these are ropes of fascines, which form a network above and below the grondstuk, constructed as follows :-The workman drives two stakes into the ground, about 2 feet 6 inches apart, to which he secures a cross stickabout 2 feet 3 inchesfrom the ground. A series of these frames are erected about 2 feet apart, the number beingdependent on .the size of thegrondstuk and consequent length of the rope, or wiep.