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THE CARDIFF SEWERS. MR. WAKING'S REPORT. We subjoin an abstract of the report presented by the Town Surveyor to the Board of Health on Friday:— THE OUTFALL. The outfall of the whole system of your sewers has been fixed at the eastern extremity of your district; in tne first place, as being the most distant point from any existing or probable buildings and in the second, as being to leeward of prevalent winds and it appears that of the numerous plans submitted in 1853. those only which proposed an eastern out- fall met with the approval of the General Board of Health. The level of the outfall is fixed at high water of neap tides, and for the adoption of what seems rather a high level for the locality, Mr. Hawkshaw assigns the following reasons. In his report of August, 1853, Mr. Hawkshaw says:—"Per- haps, looking forward to an extension of the town eastward, beyond the present boundary of the borough, may be consi- dered at present an unnecessary caution but Cardiff is growing with almost unprecedented rapidity, and may be looked upon as an exceptional case. I have not, therefore," overlooked this possibility, and it had some influence in lead- ing me to fix the level of the outfall so high as high water of tleap tides, by doing which you will have the power of ex- tending the sewer at the same gradient at a future period to an outfall still more eastward." Of what importance this ex- tension eastward is, or may shortly become, the Parliamentary proceedings of recent sessions relative to additional docks and railways are a sufficient indication. THE GRADIENTS. The level of the outfall being decided, the gradients or rates of inclination at which the sewers can be constructed, must be governed by the level of the basement floors, as also by the levels of any canals, waterways, or sunk roads, which it may be necessary to pass under, and it follows that the lower these natural obstacles are at the upper part of the svstem. the less fall is available for the sewers, and the less fall the slower the currents. In the North West District, there are four of these points which are fixed, and from which there could be no deviation, viz.:—the dock feeder at Her- bert-street. and at Bute-terrace, the Glamorganshire Canal at St. Marv-street, and the Junction Dock (for the Bute-town sewers) near Bute-street bridge. The fact of the small fall obtainable between the invert of a sewer passing under these points and that of the outfall, rendering artificial aid neces. sary to keep the sewers clear of deposit, and water for the purpose being apparently available at Broad-street, led to the whole of the sewers in Mr. Hawkshaw's upper district being laid at such levels as to admit a current of water being di- rected through every sewer alternately from the point named. This arrangement, though forming a very complete, and in most respects a very satisfactory system, involves in three or four streets very flat gradients, and these streets being at the same time rather out of direct line of flushing, thedifiiculty of keeping the inverts clear of deposit, without manual labour, is considerable, and shall be again reverted to. With the ex- ceptions already alluded to, the flushing in conjunction with the flow of sewage water answers the purpose intended of keeping the sewers clean of sewage matter and deposit, and the working appliances are simple and inexpensive. THE MAIN SEWERS. Commencing from the outfall, the first trunk sewer, 6ft.Oin. high, and 4ft. Oin. wide at springing, runs due north in a straight line a distance of 1572 yards, with a short turn west to Tyndall-street, at the Old Long Dyke road, where it receives the two main sewers of Tyndall-street and Davis-street. From this junction, Tyndall-street sewer, 4ft. Oin. by 2ft. 9in., runs westward 755 yards, to west end of Herbert-street, at Bute-street, receiving the new southern main sewer from Bute-town, and an upper district main, from Bute-street northward. From this point, a sewer of 3f. Oin. by 2ft. 6in. reaches to the east end of Charlotte-street, receiving from all sewers west of Love-lane, and from Chailes-street to St. Mary- street and Temperance-town. This sewer is continued 3ft. Oin. high up Charlotte-street under the Glamorganshire Canal at St. Mary-street, and through Angel-street up to the Cardiff Arms, at Broad-street, where the flushing water is received. The rises and rates of inclination of this sewer vary from 4ft. lin. to 16ft. per mile. This line of sewer is practically free from deposit. The second main sewer, 4ft. Oin. by 2ft. 9in., runs from east end of Tyndall-street directly north to Newport-road, near the Infirmary,'turning west from that point, with 3ft. Oin. by 2ft. Oin., up Crockherbtown, under the Bute Dock Feeder and Glamorganshire Canal, and joining sewer No 1 at Angel-street. At the turn near the Infirmary, this sewer re- ceives all sewage from Tredegarville and part of Plucca-lane and in Davis-street, at Kite-street, the sewage from Augusta- street flows in. In this sewer no practical depost exists from point of junction with the main to the Taff Vale Railway Sta- ion, whence to Park-place, sand deposit constantly accrues, and on which account the additional side entrance between the railway bridges was constructed eight years ago. This deposit consists of sand and gravel, of which a considerable amount is brought in from the channels of Park-place, of which 1100 feet remain unformed, and also from the unfi- nished district of Windsor-place. The inclinations of this sewer are from 8lft to 16ift. per mile. z A third main sewer, 3ft. by 2ft., runs from Davis-street (No. 2) sewer, through Victoria and Adam-streets, under Dock Feeder at Bute-terrace, and up David-street and Charles-street, beir g connected with Crockherbtown sewer at the north end of Charles-street. The gradients are 4ft. Sin. to 7ft. 7in. per mile. Into these three main sewers all branch sewers from the intermediate streets, and all sewers lying northward of the Docks are discharged, the dimensions of branch sewers being 3ft. Oin. by 2f. Oin., and the gradients vary from 14 feet per mile to 5 feet per mile, according to locality. The Bute-town main sewer of the new system discharges into the main sewer first described, at Herbert-street, com- prising a brick sewer, 3f. Sin. by 2ft. tiin., up to Loudoua- square and from that point to the sea, at Penarth-terrace, near the Old Sea Lock, of 3ft. Oin. by 2f. Oin,, Penarth-ter- race being the commencement of the sewer, a connection being made with the sea at a level which allows the admis- sion of flushing tidal water at high water of e(luinoctial tides. For some time after this sewer was constructed, it was the practice to flush from this point; but with the increase of drainage area it became necessary to abandon the system, from want of storage room during high water. No sub- stitute has yet been provided, and the mode of dealing i with the question depends on the course the 'Board may take in reference to a storage reservoir. If a reservoir is constructed, the former mode of flushing this sewer may be reverted to, with sufficient frequency to keep the sewer clear, and if matters remain in their present position, a flushing tank should be constructed at Penarth-terrace for that pur- pose. The gradients of this sewer are from 3ft. 2in. to 4ft. lOin. per mile. In this sewer a deposit of sand exists between the Junction Dock and Loudoun-square, varying from nine to six inches on the invert, and southward of Loudoun- sqaare of about 3 inches. This main sewer receives the drainage of all streets and houses north of Patrick-street, with the exception of basements in Bute-road which are at a lower level; also the flow from Mount Stuart-square and the southern district, west of Adelaide-street. The Bute-town branch sewers, north of Loudoun-square, are flushed from a tank supplied from the Water Company's mains in the square, and are as a rule free from deposit except at their junctions with the main sewer, the body of water in which checks the flow of the lateral sewers at the point of delivery, and occasions accumulations which it is necessary to scrape into the main sewer, and wash away by flushing about twice a year. The Canal-parade branch par- cularly, and these branches generally, are in a much less offensive state than was the case five years ago. The sewers comprised in the scheme of 1858, so far as it has been carried out, are from their locality, debarred from the advantage of the general system of flushing; and those lying in the Adamsdown, and Tredegarville, and Plucca-lane district, and about Guildford and Edward-streets, are at such levels and inclinations as will probably-render artificial aid permanently unnecessary. The ruling gradients are, in Splotlands, 291t. and 2lft. per mile; in Tredegarville, 29ft. and 53ft. per mile. If at any time flushing should be re- quired, the system is so arranged as to admit of its easy application. The Temperance-town district forms part of the 1858 scheme, and frcm its low level flushing is necessary, and is occasionally used at inlets provided for that purpose. Main sewers fall at the rate of Oft. per mile, lateral branches, 14 feet to 40 feet per mile; some of these branches being short and of good gradients, were constructed of smaller sized culverts (2ft. 3in. by 1ft. 9in.), but although they do work with a little extra attention, their inaccessibly is a great inconvenience. On completion of sewers now in pro- gress, in this district, it will be advisable to construct a flush- ing tank at the west end of Park. street, which may be sup. plied from the river at equinoctial springs, and during high freshets. The main sewer of the district is now in course of extension from Havelock-street to Cowbridge-road. The size of sewers is such as to admit the passage of a man through them, and the junctions and side entrances are so arranged as to afford all practicable facilities for the pur- pose. Street surface drainage is effected through six-inch glazed pipes, and a variety of guiiy gratings, principally Lowe's patent cast iron box traps and a dip trap with brick pit, which, with care on part of the scavengers, is, I think, the best we have now in use. House drainage has been constructed chiefly of glazed earthenware pipes, varying in size from 4 inches to 12 inches diameter, and a few half-brick barrei drains; the practice of combining a number of houses in one large pipe or drain militates against the free passage of sewage current at the point of delivery of the drain. SAND AND GRAVEL TEPOSIT. This deposit consists principally of aand from the back yards of houses, particularly in the pourer class of cottages and crowded localities, and comprises also strong gravel, large stones, brick-bats, ginger-beer bottles, and other extra- ordinary deposits which can only be thread into the house drain pipes by taking up the trapped grids, which is stated to be a rather common custom. In a sluggish cuirent through some of the branches which do not admit of a very direct course for the flushing water, this sand and gravel gathers gradually, and when the sewage current is entirely stopped by back sewage during the time of high water, the deposit accrues, and becomes so firmly settled, as to render it impossible to move it by water alone under the present arrangements for flushing. Ttib occurs in the following, in which manual labour is necessary f"r removing the de. posit abojt once a quarter, viz :—Stanley-street, (which has just beeti cleared), Love-lane, (cleared two months ago), east end of Bridge-street, (now being done), Ellen-street, North William-street, and Thomas-street, (now requiring attention.) In Love-lane an error in construction of the in. vert aggravates the evil, and it would be most satisfactory to have that corrected. The chief differences in the extent of deposit occur in (1.) Bute-street, where the sand deposit was in i860, two inches; in 1863. three inches and 1866, five inches; a depth taken in 18i2 giving four inches; this wouid give an increase of three inches from 1860. or one inch from 1862. (2.) Bute-terrace, West-end at the junction with Bute- street in I860, nothing; 18U3, six inches; and in 1866, five inches; a depth in 1862 giving seven inches, shewing in this sewer which serves the district between Frederick-street and Charles-street, a decrease during the last four years. (3.) Ivor-street, near the east end of Newtown, shewing in 1860, eight inches of sewage matter; in 1863, seven inches of sand; and in 1866, six inches of sand; an intermediate depth in 1861 giving nine inches of sand, thus showing a de- crease from 1861 of three inches, or a clearance of the 8in. of stagnant sewage matter of 1860 with a substitution of 6in. sand. (4.) In the same vicinity is the Kite-street outfall from Adamsdown, shewing an apparent increase of four inches sand, which is in reality, a substitution of that item for eight inches of sewage matter in 1860, while in 1861, eight inches sand is stated, shewing a decrease of four inches in the five years. (5.) Pendoylan-street, on the south side of South Wales Railway in Newtown, shews a total accretion of four inches depth, from 1860 to 1863, the same being maintained to the present time: the remaining streets in this small district known as California being in a manner locked by the height of water in the main sewer immediately adjoining, have no chance of acquiring sufficient current to carry off sand and gravel deposits, a depth of thirteen inches sand and sewage matter with an inch of water flowing over and with it, being the general state of the lower end of these streets. THE REMEDY. In main sewer No. 2, in Crockherbtown, I recommend the construction of a side entrance near the crossing of the Dock Feeder, with a sunk catch pit to form an artificial fall for the sand, and for convenience of removal. A catch pit at the grids in Park-place would be of service, and if my re- commendation of four years ago to construct proper surface channel? up this street were adopted, the evil complained of would be very much lessened. The side entrance would be of use also for more convenient inspection of the iron pipes under the feeder. fn the streets lying between Nelson-terrace and Bute terrace, I recommend the construction of flushing valves at the south end of Charles-street and Mary Ann-street and Love-lane, by which the flushing stream may be backed up to increase the head and velocity. The removal of sand from the upper part of the town has been much less general since the practice of flushing from the Dock Feeder overflow has been in use. The California district in Newtown between the South Wales Railway and Tyndall-street, is more difficult to deal with from its proximity to the main sewer with which the branches join on a level invert, and which, in October and on the 16th of the present month during a strong frost, passed at neap tides and at low water of spring tides, 16 inches of water. For some reason, which was, no doubt valid at the time, probably for the purpose of keeping the outfall level as high as practicable, the delivery of the branch sewers into the mains, is in all cases at the level of the invert. This arrangement admits of the branch sewers being kept at a greater depth below cellars, but it has the greater disadvant- age as I consider of necessitating a much more rapid current in the main sewer to maintain an effective discharge from the branches. Under existing circumstances, I do not see any very satisfactory remedy for this inconvenience, but I think the formation of a catchpit at the west end of Ellen- street, into which the sand deposit could be washed from a flushing sluice to be fixed at Pendoylon-street, would have as good an effect as any means at present available. If at any future time the main sewer No. 1 should be continued east- ward from Tyndall-street, I think it would be advisable to take off the arch through Tyndall-street and lower the in. vert fifteen inches or thereabouts, making the diverted portion proportionately lower. This would increcse the current of the Bate-town main sewer also, and benefit the branches. The deposit in Bute-town is chiefly in the main sewer, between Sophia-street and the Junction Dock, and in the junctions of Sophia-street and South Church-street, and pro- bably the junction of Maria-street. A side entrance and catch pit at Brewery-street, near the junction Dock, would facilitate the removal of this deposit, which with a little extra flushing would be kept under with little trouble. It will probably be necessary to construct a flushing tank at Penarth terrace, to be supplied by the Water Works Com- pany, in substitution of the tidal flushing formerly used for Eleanor-street, Dudley-street, and Mount Stuart-square sewers. THE FLOODING OF CELLARS. The next and greatest point of consideration is the amount of flow of sewage and water to the sewers, and the amount of space provided for its reception, and the facilities of discharge. Under ordinary circumstances of calm weather, the outfall doors are, by repeated observations, found to be closed from 6'1 to 4 hours at all tides, giving 26 feet on the East Dock sill, and this was the case on thirty-nine days during August and September last, and will be the case on two hundred and twenty-four days during the current year. The constant quantity ofwater passing reduces by so mueh the cubic area of sewers available for rainfall passing to the sewers during, or immediately preceding the rise of tide, and the limit of their capacity is further fixed by the levels at which basements are built, and at which sewage water will flow into those basements. Then come the extent and period ofrainhits. Now at the moment the lowest of the three tidal doors is closed, the flow of sewage is stopped, and the quantity begins to accumulate. I have ascertained by measurement of each sewer, that the amount of available space for storage at this time of stoppage which can be used up to the level of basements in Loudoun square, they being at a higher level, and basements in Loudoun square, they being at a higher level, and n.ore favourably situated than cellars and kitchens in New. town, is in the whole 173,614 cubic feet, equal to 1,081,600 gallons, and this involves the complete filling of the main sewer, all sewers in Newtown, Adam-street, and Bute-terrace, and the partial filling of all other sewers up to Caroline- street, Charles street, and in Bute-town to Patrick-street. On thelCth inst., during the hard frost, and at dead neap tide, the discharge of your main sewer was at the rate of 25,000 cubic feet per hour, giving a 100,000 cubic feet in the four hours of closed doors; this amount deducted from the gross capacity of 173,614 cubic feet up to flooding level, leaves a cubic area of 73,614 feet to accommodate any rainfall that may happen, or any thaw that may take place shortly pre- viou. to high water, or during the rise of the tide. The total surface area at present drained by the sewer system is, omit- ting docks, canal, and feeder, 488 acres, and over this area rain falls at various times, and in various quantities. The proportion of water flowing to sewers from a shower varies according to the description of surface on which the fall takes place. On land occupied by streets and buildings the discharge appears to vary from 52 to 80 and 90 per cent., the latter being no doubt exceptional. On agricultural land, the quantity will not be much less than 50 per cent., if the soil is already soaked by previous falls; hut the time occupied in the discharge will be longer. Setting aside the 3in. which (according to observations taken at the Town Hall), fell on the 4th September, and taking the *72in. which fell on the 28th, near the time of high water, and assuming half the quantity to pass to the sewers, and one-fourth of it during the period the doors are closed, say 3i hours, we have a quantity of 318 786 ft for a storage of 73,614, c. ft., leaving 215,172 c. ft., or a million and a half gallons of backwater to be stored temporarily in the kitchens and store cellars, of which complaints have so frequently been made, and fully accounting for the depths of 17, 19, and 24 inches, stated to have been experienced. The fall of 108 inch on the 24th of last month with high spring tides, assuming one-halt of the fat! to pass to the sewers, and only one-third of that half to flow into them during the rise of tide just previous to high water, would give an excess of 1,797,809 gallons beyond the storage-room available up to the point of flooding basements. These are not strained cases, nor excessive falls, as you will see by the register table, nor is the time calculated on for dis- charge unreasonable. Formal complaints of inconvenience and damage suffered from the overflows of back water, have been before you since 1861, shortly alter the completion of the extension drainage, and with eiery increase of area, the evil and consequent complaints have increa.-ed. The whole question seems to me perfectly simple. The sewers are stopped from discharging at certain periods, easily ascertain- able they are of a certain cubical capacity, admitting of de- finite measurement; a certain portion of that capacity is oc- cupied by a nearly constant amount of sewage and deep subsoil drainage; and another portion of the capacity, being above the level ot basements in the lower part of the town is useless as storage room the amount of rainfall to be pro- vided for, is the only indefinite item in the account, and the experience of hydraulic engineers who have specially studied the subject, ought to form a reasonably safe guide in that particular. The only remedy I can recommend is the one which has so often been pressed on your notice, viz.: a storage reser- voir at the outfall of the sewer, to hold two million gallons of back water, and with the necessary valves, overflows, and appliances. This or a similar reservoir is described in Mr. Hawkshaw's original report of 1853. Owing to want of statutory power to take land, the construction was deferred, and on completion of the first sewer scheme in February, 1857, Mr. Hawkshaw reports to you, in consequence of the Board having no power to secure the requisite land, this re- servoir was not included in the contract for works. I refer to this now, because I consider with the rapidly increasing drainage area of this town, this provision for relieving the sewers during the period of high water and in storms of rain will be essential to the perfect drainage of the district, and you ought as soon as you conveniently can to provide for its construction. I again obtruded the subject on your attention in Septem- ber, 185iS, and in March, 1809, a design for a reservoir at the present outfall within the district, was prepared, and by your direction submitted to Lord Bute's engineers, carefully ex- amined and approved by them. This being done, the re- commendation was rejected by the Board, and the matter remained in abeyance until 1863 and 1805, when subject to the passing of a Bute Dock bill, involving a diversion of the sewer, an arrangement was made between the respective engineers, by which the construction of storage room was again provided for, and for the entire cost 61 which, inclusive of land and all contingencies, you were to contribute a sum of £4,.)1)0. The curtailment of the dock scheme, rendered the con- tingent diversion of your main sewer unnecessary in respect of works for which Parliamentary powers were given, and matters appear now to stand in the same position as in 1858, cept that it now seems clear you have power to obtain land compulsorily for constructing a reservoir in your own district. CATHAYS PROPOSED DISTRICT. Subject to the provision of sufficient storage room for storm waters, there is no difficultv in draining this district into the sewers system. It was in fact, included in the scheme of 1S58, the sanction of the Secretarv of State was obtained for borrowing funds money was borrowed, and pending the settlement of the reservoir question, was tem- porarily applied for purchase of houses in High-street and other streets, in preference to raising another loan, and keeping the drainage balance at your bankers. Good falls for the sewers are obtainable, the least fall being 20 feet per mile; no flushing will be required, and the necessity of drains is now great; streets constructed ten years ago remain undrained, and as I have on previous occasions stated, cesspools and cloets in Lord Bute's portion of the district still pass by the old drain through "Cooper's Field," into the river Taff. The works at present required, are a main sewer from Tredegarville to Cathays, parsing through the street recently laid out, and now beiag built on, called Upper George-street, and branches up Cathay's-terrace and Catherine-street. The cost of this with ventilators, side entrances, and gullys shoots, I estimate, at £ 1,400. BUTE ROAD OLD SEWER. The nuisances arising from the retention of the old culvert in Bute-road, constructed by Lord Bute's Trustees fifteen years ago, and retained for flushing the Packet Slip, and draining the south end of Bute-town, are constantly on the increase, and must be so as long as the culvert remains in it present condition. I would recommend you to close this sewer entirely north of Hannah-street, and drain the surface channels of Bute-road into your own sewer running parallel with it at about li 0 feet distant, constructing proper catchpits at the street grids for stopping and collecting deposit of road detritus, which in the limestone used for roads in Cardiff, is a very difficult matter to deal with in a flat sewer. Also, to con- sider seriously the necessity of diverting the culvert south- ward, in which I.ord Bute's trustees would probably meet your wishes. VENTILATION AND ESCAPE OF FOUL GASES. The system of ventilating the sewers into the streets direct, reduces the tendency of the foul air to make its way into the houses and back yards, through house drains as it un- doubtedly would, and as it occasionally does, where stench traps are neglected or removed. Great complaints have, however, been received during the last six years from householders in every quarter of the town, and from medical gentlemen, of illness caused by the inflnx of foul air from the street ventilators into the houses. This is caused by the air issuing from the shaft passing in the direction of the wind in a continuous stream at a level of about two feet from the surface of the street, through the first open doorway or window, into which a little extra draught exists. In the day time this is generally imperceptible to the eye, but in the early morning, the external air being considerably colder than the vapour, the latter is condensed, just as the breath is condensed on a frosty morning, and assumes the form of a stream or column of condensed steam. The state of the tide has nothing whatever to do with this condensa- tion, which is merely a question of comparative tempera- tures; but the efflux of the foul air is made evident when the back pressure of water in the sewers is not felt and it must be apparent to any unprejudiced person that the rate of efflux and consequent quantity of foul air discharged when the air in the main sewers is being displaced by back water, must be very considerably increased. I have been compelled to close several of these outlets in Bute-street, Bute-town, Temperance-town, Newtown, Crock- herbtown, and ether localities, on reiterated complaints of inhabitants in their vicinity and you are now trying the effect of a deodorising charcoal chamber in half a dozen places, with a view to a more extensive adoption of the sys- tem, if the system is favourable. Direct communication by flues has been made with engine chimneys in the few cases available, the most effective draughts being at the Cardiff Gasworks, with a circular flue 18 inches in diameter, and a velocity of 1.025ft. per minute; and at Messrs. Hill and Sons', West Dock, with a flue of 15 inches diameter, and a velocity of 430ft. per minute. Should the charcoal ventilators prove inefficient, I think it will be necessary to construct three or four special ventilating chim- neys in the flatter districts of the town but further observa- tions on the temperature of the sewers, and the action of pre- sent ventilators, are desirable before recommending definitely any considerably outlay. COSL OF DRAINAGE. The amounts expended in your drainage works, from the formation of the Board to this date are:— I Mr. Hawkshaw's design, under contract with Messrs. N. and D. Jones, and certified by him £ 24,384 0 7 Completion of same in Bute-town, by Messrs. Joues, and certified by me 2,249 15 0 Total cost of Mr. Hawkshaw's design, omitting In reservoir not constructed £ 26,624 15 7 Extension scheme of 1858, part complete 7,47b 19 6 Additional protective works to outfall, subse- quent to construction, to check encroach- ments of the sea 687 0 0 Extension of branch sewers in various parts of the district, flushing tanks, conduit, &c. 2,200 0 0 Total ccst of drainage works and extensions,to date £ .36,988 15 1 The cost involvel in the works recommended for p resen improvements of existing sewers I estimate as follows :— Two side entrances, at Stanley-street and Love- lane, already ordered 50 0 0 One ditto, at Adam-street, already ordered. 20 0 0 One ditto, at Crockherbown, ditto One ditto, at Bute-town, ditto f lfw- n One ditto, at Ellen-street, Newtown, ditto One ditto, at ditto Flashing valves at Charles-street, Mary Ann- street, Love-lane, and Pendoylan-street 60 0 0 Stop doors in Bute-town main sewer, for flush. ing, six 18 0 0 Catch pans for ventilating shafts, to renew, 60. 52 0 0 X300 0 0 The amount required to be expended to complete the ori- ginal plan, as designed by Mr. Hawkshaw, and the extension plan for existing streets in the Cathays district, as laid out by myself, I estimate at :— For outfall reservoir works £-1,500 0 0 For main sewer to Cathays, and sewers in Cat- hays-terrace and Catherine-street, including entrances and surface drainage 1,100 0 0 A block of land lying between Plucca-lane, Cathays, and the Taff Vale Railway, is now being laid out for building purposes, and will shortly require an extension.of drainage in that vicinity. CONCLUDING REMARKS. The foregoing remarks, with the aid of the following tables and plans, will, I trust, place the condition of the sewers, and the improvements which I consider necessary, as cltarly before you as the nature of the case admits. [ cannot claim any of the credit due to the original design, which I think experience has shown to have been well con- sidered, sufficiently comprehensive, and well suited to your district, and which certainly has offered every facility for extensions beyond the first area. Experience of the working of the system during the ten years it has been in operation would naturally suggest several minor points which are sas- ceptible of amendment, and which have been already de- scribed. But I may venture to state that no engineer ever designed a work which, after ten years' experience of its action, he would not be able to improve. Assuming that the scheme, as at first designed, were completed, I see no reason to doubt the permanent efficiency of the sewers, nor that the overflowing of basements will be prevented.