1845.] 



THE CIVIL ENGINEER AND ARCHITECTS JOURNAL. 



351 



perience, unwearied zeal, and perseverance, accompnnied bj no ordinary 

 ability, entitle him to great praise. The laie inilefiilinaljle clerk. Mr. 

 Nicholson, and his successor, Mr. Hett, deserve ulso particular mtatiun. 



Odsfrvations. 



Sir John Rennie, President, said, it would be observed, that in tlie 

 paper he had brought prominently forward some leading principles of 

 drainage, which he thought were very important. 



There were, Ist, The formation of ' catch-water ' drains, which separated 

 the highland from the lowland waters, and conveyed each to independent 

 sluices, at the lowest practicable outfalls. This system was, he believed, 

 first practised by the late Mr. Kennie, about the year 1801, in the W'itham 

 draiuage. 



2nd, The straightening, deepening, and general improvement of the main 

 river, separating, as much as possible, the navigation from the drainage ; 

 aod- 



3rd, The formation of over-fall weirs and reservoirs, for arresting the 

 sand and mud, and preventing the drains from being choked. 



The advantages of these plans must be evident, particularly for a flat 

 district, surrounded by high lands. He was opinion, that the defects, 

 complained of in the Bedford level, might be attributed, in a great degree, 

 to the nc gleet of these principles, and the continuance of the old Dutch 

 plan, of simply cutting a series of straight drains to the nearest point in 

 the river, without suHicient regard to the outfall, where only as much of 

 the water was discharged as was allowed by the time the sluice gates 

 could be permitted, on account of the tide, to remain open. This plan 

 alone was, he believed, still pursued in Holland. 1 he attempts to drain 

 the Pontine Marshes, under Pius VII., had been conducted on that prin- 

 ciple, and even M. Prony, who v^■as sent to Italy by Napoleon, for the 

 purpose of reporting on the drainage of those marshes, made no other 

 suggestion. 



It had been asserted, that the Carr Dyke, which was constructed at the 

 foot of the high lauds between Peterborough and Lincoln, had been in- 

 tended, by the Komais, for a ' catch water' drain and for a canal ; but 

 (Jiere was not any distinct evidence of the fact. 



The works of the Nene Outfall, which were executed under Mr. Tel- 

 ford and Sir John R> nnie, had cost about £100,000. By that great work, 

 the low-water mark had been lowered 10 feet 6 inches, and in conjunction 

 with the North Lever drainage works, which were executed under Mr. 

 Telford, nearly aO0,0O0 acres of land were most ed'eclually drained, which, 

 previously to that time, had been almost without cultivation. A further 

 example of the effect of drainage might be given, in the Thoruey estate, 

 of 20,000 acres, belonging to the Duke of Bedford. It was slated, that 

 at times, previous to the drainage, scarcely any rent had been paid ; but 

 now, in consequence of the improvement of the land, from the system of 

 drainage, towards which his Grace had contributed about £100,000, an 

 annual rental of nearly £25,000 was paid. The navigation of the Nene 

 up toW isbeach was also so much improved, that large vessels now arrived 

 there, and the trade had been nearly trebled. At Sutton Bridge, about 

 8 miles below Wisbeacli, where previously only moderate-sized colliers 

 could arrive, even at spring tides, vessels of nearly 700 tons burthen could 

 now be brought up, at ordinary spring tides. The flow of the tide, which 

 formerly seldom exceeded between 1 1 feet and 12 feet, now attained a 

 height of upwards of 21 feet, besides securing al low water a depth of 

 between 5 feet and G feet in the channel down to the sea. 



Mr. I{. Stephenson said, that the system of ' catch-water' drains would 

 not be generally applicable in Holland, on account of the flatness of the 

 country, there being little high land, except near Utrecht. 



SirJoEiN Rensie, President, thought the Dutch, with all their talent 

 and patient industry, had been somewhat too strongly attached to their 

 old plans. In his opinion, if they had done more by warping on their 

 coasts, they would have succeeded better, and would have saved much 

 eipense of embanking. 



Overfall Weirs. 



Mr. J. Smith (Deanston) said, that possibly the farmers were satisfied, 

 because the present stite of the district was so much superior to its former 

 condition ; hut if the level of the water was reduced still more, they might 

 perhaps be better satisfied. With respect to the overfall weirs and reser- 

 voirs for arresting the sand and mud, there was no doubt of their actual 

 utility, and every district would be improved by their introduction. In 

 the present system of surface drainage, large quanti'ies of the lighter 

 particles of the soil were carried by the water, along the open furrows, 

 into the drains ; thus lilling them up, and at the same time depriving the 

 fields of their soil. This would, however, be in a great degree prevented, 

 when subsoil drainage was more extensively introduced. The surface of 

 the land would then be so arranged, that the rain woukl filter through into 

 the drains, and it was now found, that even in very {rainy seasons, the 

 water from subsoil drains was but little charged wiih sand, or earthly 

 particles, and that it could be used for luauy purposes, for which the 

 drainage water had previously been unfit. 



Mr. GiLi'S must contend, that there was no necessity for placing the cill 

 of the outlet sluice lower than 2 feel below low-water mark. It was not 

 possible to drain to below that point, by natural means ; and no extra 

 ■mount of discharge would be obtained by going deeper. But, on the 

 other hand, there would be a considerable deposit of silt agaiust a cill 

 placed deeper than 2 feet, and the gates would be prevented from shutting 

 accurately. 



Mr. J. M'alki.r said, although it was true that natural drainage could 

 not be carried below low-water mark, yet in order to drain down to that 

 level, the cill of the outlet sluice should be placed as much lower as was 

 practicable. It should be recollected, that the gates only remained open 

 fur a short time, during which period it was desirable to discharge as 

 much water as possible ; then as the quantity, passing through the gates, 

 could be appreciated by multiplying the depth of 2 feet down to the cill, 

 into the width of the opening, and by the time the gates remained open, 

 it was evident that if the cill was fixed at G feet or B feet below low-water 

 mark, the greater depth, multiplied into the same width, would give a 

 greater sectional area, for the passage of the water, in the same time. 

 'Hie friction of the water would also be less when dowing in a mass of 

 good depth, than when it ran in a comparatively thin stream over the 

 cill. 



Drainage near Scarborough. 



Sir George Cayley observed, that he had been for more than thirty years 

 one of the directors for carrying out the provisions of the Muston Drainage 

 Act, including about 10,000 acres of laud near Scarborough. This drainage 

 was effected under the direction of the late Mr. William Chapman, of 

 Nivvcaslle-upon-Tyne, who had great experience in such matters. The 

 drains appeared to combine in their just and most economical proportions 

 the two adverse principles at issue in the previously expressed opinions. 

 In that extensive and gently rising marsh, the dead level principle was 

 adopted from the lowest outfall, till the surface of the water in the drain, 

 at ordinary times, was within about four feet of that of the soil, which 

 level was found suHicient for the purpose of draining the adjacent lands. 

 From this point, the drains took the average rise of the marsh, and conti- 

 nued it for several miles; thus furnishing, at the cheapest possible rate, a 

 very useful and ellicieut drainage, to all the lands under the Act. Had 

 the dead level been continued throughout the whole length, the expense 

 would have been enormous, w ithout rendering the drainage more complete, 

 and had the dead level not been brought up to the point named, many 

 hundred acres of the lower portion of the swamp would not have received 

 any benefit. 



The general plan of the Muston drainage might be thus stated. The 

 small ri'vers Hartford and Derwent, with several brooks, held their courses 

 through an extensive marsh, and in times of heavy rain, they overflowed 

 their banks and flooded the land to a great extent. No expense whatever 

 was incurred, for cutting channels, deep enough to convey away the flood 

 waters of these rivers, or brooks, but they were allowed to keep their an- 

 cient levels, and embankments were made near them, on each side, 'y 

 cutting deep back drains, for carrying the dead water from the lands, and 

 casting up the soil excavated from them, on to the sides next the rivers or 

 brooks. By this process, all the great body of waler was conveyed, in 

 tinieso'f flood, within these embankments to the lowest outfalls, and the 

 deep cutting, which he considered the •' sine qua non" of an efficient 

 drainage, and the expensive part of it, was entirely confined to such mo- 

 derate sized drains, as were suflicient merely to convey the dead water 

 from the land. Another practical advantage, of the deep back drains 

 being contiguous to the embankments, was, that when they received any 

 injur'y from cracking, after long droughts, or the burrowing of moles and 

 water rats, and thus permitted the flood-water to pass in some degree 

 through them, the back drains interrupted it, and preserved the land from 



Theori^inalcost of this draiuage was about £40,000; and the annual 

 repairs averaged about £800. The improved rent was obtained at about 

 four or five years' purchase. , , , , . 



The expense of this drainage had been much increased by local circum- 

 stances, and which could scarcely be supposed to occur in any other cases ; 

 and therefore it was unnecessary to detail them ; but these circumstances 

 took place at a distance from the marsh land, and in no way invalidated 

 the state of the case. ,...,,,,.,.,. 



Sir John Kennie, PmirfcH*, said, that Mr. Telford, in his drainage works, 

 had as nearly as possible acted upon an uniform system, similar to that 

 which had been described; but that, in particular cases, it was necessary 

 to adopt peculiar methods. It was certain, however, that in all cases, it 

 was essential to commence the drainage at the lowest point of outfall, and 

 to work iuwards, towards the head of the marsh. In the Bedford Level 

 that system had been neglected, and to that circumstance Sir John Rennie 

 attributed much of the difficulty that had been experienced. 



It was always a point of importance to restore the rivers to their natural 

 state,of main drains for tliecounlry. At Boston, in the year 1820, he re- 

 collected seeing the bed of the river nearly dry, at the time of what ought 

 to have been high water. Since then, tlie outfall below Boston had been 

 improved, by making a cut across Burton's Marsh, and improving the 

 channel of the river upwards, upon a plan proposed by him ; the effect of 

 ihese works had been such, that vessels, drawing upwards of 14 feet of 

 waler, now arrived at ISostou. 



The Academy of Sciences of St. Petersburgh is prepariag an edition of the 

 works of liuler more complete than any hitherto published, for it will con- 

 tain several tracts deposited in MS. in the library of the University of 

 Dor-isat which have never yet been printed, besides others preserved ia 

 various libraries of Germany.' The edition will form thirty volumes. 



