146 ADDY ON THE WATER-SUPPLP OF PETERBOROUGH. Winutes of (Pap@ No. 1895.) (( The Water-Supply of Peterborough.” By JOHN ADDY,M. Inst. C.E. PETERBOROUGH,on the Nene, and in the water-shed areas of that river and the Welland, was incorporated as a municipal borough in 1874. Previously to the incorporation, the Improvement Com- missioners, asthe urban authority, urged byfrequent zymotic invasions, by the tooobvious presence of organic impurities in the water, derived from shallow wells, public and private, as the sole source of supply,2 and frequently by long periodsof absolute water-dearth, had been compelled to consider the advisability of providing water from some extraneous and abundant source ; but no active initiatory steps hadbeen taken. The Corporation, however, on its establishment determined to introduce an abundantwater-supply and a new system of drainage simultaneously ; and accordingly, in August of the same year, the Author was instructed to prepare schemes for both purposes. The. The discussion upon this Paper was taken together with that upon the two pl-eceding ones. As an example of Peterborough waters at thistime, take the following:- ANALYSISof WATERfrom TOWNP-, PETEBBOROUGH.JUNEllth, 1873. Expressed in parts per100,000. (FrmSixth Report of the Rivers Pollution Commission, p. SS.) Total solid impurity ........... 213.800 Organiccarbon ............ 0.321 Organicnitrogen. ........... 0.113 Ammonia. ............. 0.000. Nitrogen as nitrates and nitrites ...... 7.768 Tital combinednitrogen ......... 7.881 Previoussewage or animalcontamination ... 77,360.000, Chlorine .............. 22.100 Hnrdness,Temporary ......... ’ 27.300 ,, Permanent ......... 64.300 ,, Total ............ 91.600 REMAEKs.-c!ear. Slight saline taste. Downloaded by [ UNIVERSITY OF OXFORD] on [12/09/16]. Copyright © ICE Publishing, all rights reserved. I.+l'', l p Mile PETERBOROUGH WATER WORKS, SECTtDN COMBINED WITH PLAN,SHDWING COURSE OF MAIN CONDUIT. RESERVOtR, SECTION ON LINE. kf!.(' 1l.F.. ( OBLIQUE -ORTHOGRAPHIC PROJECTION ) FLAN OF THE RESERVOIR,CAPACITY 1,000,000 GALLONS Downloaded by [ UNIVERSITY OF OXFORD] on [12/09/16]. Copyright © ICE Publishing, all rights reserved. Prooeedings.] ADDP ON THE WATER-SUPPLY OF PETERBOROUGH. 147 water scheme described inthis Paper is theresult of these instructions. An exhaustive examination of all the sources available in the neighbourhood of the city revealed but two, the river Nene and the Marlstone rock of the Lias formation, that promised to yield a supply adequate in quantity,while, even of these, the former failed to meet the requirements in point of quality. Thelatter, the Marlstone rock, underlying the sands of the middle Lias, would be reached, it was expected, at a depth of about 150 feet in theneigh- bourhoodof Castor, a village about 5 miles from Peterborough. At Northampton, a well sunk into this bed was supplying 864,000 gallons a day, and geologists expressed the opinion that a similar supply could be acquired near this village by boring. This was, therefore, mentioned in the report to the council as a possible source; butthe Authorfelt it necessary to seek for a larger supply, and one that could be confidently relied on to produce an equivalent to the maximum prospective requirements of the borough. Such a supply existed at Braceborough, and was adopted by the Author, although lying at a distance of 104 miles beyond the municipalboundary. The Corporation accepted the report, but determined to make a trial boring at Castor. This was com- menced in January 1875, and proceeded at an average rate of 1-936 foot per diem, until on June 7th a depth of 286 feet 6 inches had been reached, at a cost of 5338 16s. 6d., when no large quantity of water having been found, the boring was abandoned, andattention given solely to Braceborough asthe source of supply. THEWATER AND ITS SOURCE. The water is found in theOolite formation, in the bed between the Estuarine Clays and the Lincolnshire Oolite Limestone (called locally ‘‘ the water rock ”), the former being the lowest stratum of the Great Oolite, while the latter is the uppermost member of the Inferior Oolite.One of the main branches or tributaries of the River Glen has cut its channel partially through the Estuarine Clays for some miles above Braceborough Spa. This channel may be said to be a groove cutting more and more deeply into theclays, as the river falls in its course, and thus continually approaching the limestone under it, which bears the subterranean waters, until a point is reached where the stratumof Estuarine Clays under the L2 Downloaded by [ UNIVERSITY OF OXFORD] on [12/09/16]. Copyright © ICE Publishing, all rights reserved. 148 ADDY ON THE WATER-SUPPLY OF PETERBOROUGH. [nhutes of groove, owing to its thinness, or perhaps faulty ” nature, can no longer form an impervious division, or resist the upward force of the imprisoned waters. Thispoint occurs inthe riverabout 2 miles, measured upits course,above Braceborough Spa, and from it tothe latter place theriver is studded withsprings, throwing up water with suchforce as to show distinctly above the surface of the rapidly-flowing stream. These eruptions, appearing at firstsingly, and at widedista.nces apart,gradually reach a climax lower down at the Caudles,” and again at Braceborough Spa, at both which spots the beds of the river, and of streams and pools adjacent, seem to some extent riddled bythe number of vents for these waters. Below the latter outpouring there appear to be no springs of note, and shortly afterwards this tributary joins the Glen, which then enters the alluvial formations of the Fens. The same vein of. water is reached at Bourne by boring to a depth varying from 85 feet to 102 feet, the water at times rising to a height of 40 feet above the average level of the town, and by itsnatural pressuresupplying even theupper stories of most houses there ; but this pressure is subject to considerable fluctua- tions, and at other times fails to supply above the level of the ground floors. Fromthe same townand source, Spalding also takes its supply from a boring 91 feet deep, and thereare, besides, twelveother borings for private uses. In thedistrict directly north from Bourne, and especially in that portion of it immediately skirting the Fen formation, the same vein has been tapped and rendered available by a number of borings, some par- ticulars of which are given in the Appendix. Mention ought also to be made of the noted Well Head ” at Bourne, as a display of this water in the form of natural springs, yielding, when gauged in 1874, at the rate of 4,600,000 gallons in twenty-four hours. At Horbling, too, there is a natural springof some note. The area of this water-bed has not been in any way defined, but it is most probablyconterminous with the particular strata to which it is confined, so far as those strata are continuous. The water, whereverthrown up from this source, is clear, sparkling, palatable, highly charged with carbonic acid gas, and, at times, giving distinct evidence of sulphuretted hydrogen, but thisrapidly passes off. Analyses of the water from this vein, collected from four different points of outflow, natural or artificial, are given below, and, as a series, they present features of some interest. Downloaded by [ UNIVERSITY OF OXFORD] on [12/09/16]. Copyright © ICE Publishing, all rights reserved. Proceedings.] ADDY ON THEWATER-SUPPLY OF PETERBOROUGH. 149 AXALYSESof OOLITICWATER as SUPPLIED by RIVER,SPRINQS and BORINGS. Expressed in parts per 100,000. 11. l 111. IV. River Glen nfte hrine near Wnter collected from . bpring water. --Date . April 21,1876. TOT. 22,1813. INov. 22,1813 'ebruary 26, 1876. Temperature, Fahrenheit 42O 51O 490 52' Total solidimpurity . 39.100 42.920 42.760 40.500 Organiccarbon . .. 0.104 0.217 0.089 ,, nitrogen . .. 0.020 0.047 0.025 Ammonia . 0.000 0.000 Free ammonia . 6010 .. .. o.*boo Albnmenoid ammonia . 0.042 .. .. 0.002 Nitrogen as nitrates and nitrites . 0.000 0'000 0.000 Oxidized nitrogen . 0.340 .. Total combined nitrogen .. 0 'b20 0 '047 .. Previous sewage or ani- mal contamination . .. 0.000 0.000 .. Chlorine . .'l 1-350 2.100 3.1001.950 Hardness-Temporary . 17.700 23-400 23.400 21 -500 ,, Permanent. , 5.300 11.800 11.800 6.700 ,, Total . 23.000 35.200 35.200 28.200 Remarks . Very turbid Clear and Clear and) .. palaiable palatable Analysedby 3ivers Pollution Com- Dr. Odling. Dr. Odling { mission (6th Report) The fluctuations of pressure, under which this water appears, have been referred to in the case of the Bourne supply. At the well now supplying Peterborough, when there hasbeen no draught from it, the water-level has varied from 9 feet above the ground- surface, to 8 feet below it, giving a range of 17 feet; while the normalheight may be said to be 4 feet above the surface, or 56 feet above Ordnance Datum. The groundlevels at Peterborough, referred to in the same datum, vary from 15 feet as the lowest, to 50 feet as the highest point, and the mean level of the populated area is 37 * 19 feet ap- proximately. Thus from the minimum water-level, given above, to the lowest level of the city, there is a fall of 29 feet, while to the highest point there is a rise of 6 feet, and to the mean level again a fall of 6 - 8 feet. It should be remarked, however, that the water-levels given above are approximate only,-the results of but limited observation, and it is extremely probable that the level 44, stated as a minimum, will be found, after some years' further registra- tion, to be considerably above the actual minimum. Downloaded by [ UNIVERSITY OF OXFORD] on [12/09/16]. Copyright © ICE Publishing, all rights reserved.