Well, the Report itself is more concerned with whether Birkenhead Corporation could make additional connections to the Great Culvert, and whether it could be defined as a "Sewer" for those purposes.
So there isn't a great deal about design or construction, but in order to investigate the issues above, an amount of research into the Culvert's History
had to be carried out.
It's a bit long-winded, but perhaps some of the historical references will be of interest. Most of these are from Paragraph 39 onwards.
It's also worth noting that the system all works a little differently now, with all the flows from the River Birket being pumped into the Great Float Dock via a pumping station at the head of the Great Culvert, in effect meaning that the Great Culvert now doesn't take any flows from any areas further upstream.
Borough Engineer & Surveyor's Department,
3 Conway Street,
RIVERS (PREVENTION OF POLLUTION) ACT, 1951. GREAT CULVERT.
REPORT OF BOROUGH ENGINEER & SURVEYOR
1. I report on the letter dated October 23rd, 1954, from the Mersey Docks & Harbour Board to the Ministry of Housing & Local Government. This refers to alleged contamination of the Open Cut by foul flow from the Great Culvert.
2. The River Birket, prior to entering the Great Culvert at Wallasey Bridge Road, is called the "Open Cut", and is a "Main River" under the control of the Cheshire River Board.
3. The Great Culvert was constructed in 1845/6 by the Dock Commissioners, who were the Town Commissioners at that time.
4. The Great Culvert belongs to the Mersey Docks & Harbour Board. Birkenhead pay 75% of its annual maintenance, which has amounted to an aggregate of £390 for the last 13 years.
5. The Mersey Docks & Harbour Board were responsible for a length of the Birket from its entry to the Great Culvert up to its point of confluence with the Fender Stream - a distance of 5,500 feet, approximately.
6. The Dock Board's letter contains the statement that on every tide of the year there is some back flow from the Great Culvert into the Open Cut. Whilst this is considered to be an exaggeration, it is agreed that, under certain conditions, such back flow does take place.
7. The total capacity of the Great Culvert when completely empty is approximately 960,000 cubic feet. It may be said that, when tide locked, it could fill up to approximately one quarter of this capacity, or about 260,000 cubic feet, without the level of water rising appreciably above invert level at its inlet.
8. There is a built up area of Birkenhead of approximately 1,570 acres computed to house 42,000 persons, which discharges foul and storm water into the Great Culvert through a number of outfalls through a large number of streets. The maximum dry weather flow from this area is, very approximately, 280 cubic feet per minute. Under dry conditions , therefore, this amount discharging into the Great Culvert, if it were wholly empty, would take 940 minutes, equal to 15 3/4 hours, to fill one quarter capacity, referred to above.
9. Combining these figures with the present dry weather flow from the Fender Valley Sewer, referred to hereafter, the corresponding figures give a maximum flow of 433 cubic feet per minute from a total present population of approximately 65,000, which would take 608 minutes or 10 hours to fill the Great Culvert to the same extent.
10. Though not free of assumptions, calculations have been made which suggest that during neap tides, when the Great Culvert is unable to empty itself completely and discharging head is a minimum, the available storage capacity is such that backflow will not take place, as discharge begins before the critical storage level is exceeded and is completed before the flood tide commences.
11. All the above calculations assume that the maximum dry weather flow would be maintained during the period of storage. This is not the case, particularly when high tide occurs in the early morning. During late evenings and early mornings, dry weather flow is a minimum.
12. Providing rain does not occur, this should permit emptying during a neap or spring tide.
13. In effect, the quantity of dry weather flow is not the critical factor causing backflow, being relatively negligible in relation to the surface water flow. Sewage is carried back on the natural drainage waters from the lands having a natural slope to the former Wallasey Pool. There can be little doubt of the riparian owners' rights to drain this either to the Pool as now converted into Docks, or into the drainage channel provided in lieu thereof.
14. Prior to the formation of the Birket & Fender Catchment Board (now replaced by the Cheshire River Board), the County Boroughs of Wallasey and Birkenhead employed Messrs John Taylor & Sons of London and Messrs Sandford Fawcett & Partners of London respectively as their Consultants.
15. The Cheshire River Board ultimately retained the services of Messrs Sandford Fawcett & Partners, who are now advising them on this matter.
16. The task of devising a scheme for the prevention of flooding in the catchment area has been under consideration for nearly 25 years. Any such scheme must take into consideration the present discharging capabilities of the Great Culvert.
17. The suggestion made by the Mersey Docks & Harbour Board, of placing a reflux valve at the entry of the Great Culvert at Wallasey Bridge Road, received the attention of both those Consultants in 1931. The scheme, which at that time incorporated that suggestion, included, however, for the provision of a pumping station at the entry to pump flood waters from the Cut to the Dock Board's West Float whenever the Great Culvert was unable to deal with the flood water which would otherwise rise to above the maximum permissible level and cause flooding.
18. Messrs Sandford Fawcetts, reporting to the Birkenhead Corporation in February, 1931, stated that "this scheme, involving the provision of reflux gates on the Cut to prevent liquid flowing back out of the Great Culvert into the Cut would probably cause sewers flooding in Birkenhead whenever heavy rain or the emptying of the Graving Docks coincided with a period of tide lock, as both ends of the Culvert would be closed and it could only receive the rainfall from the Birkenhead area to an extent of the available capacity of the Culvert at that time which might be inadequate. They also considered the scheme was unacceptable to the Birkenhead Corporation, and felt that the Dock Board would be unlikely to agree to a measure of flood water and sewage being discharged into the Great Float.
19. There are cellars within the area drained by the Great Culvert with floor levels of 13.00 and 14.00 O.D., compared with the highest soffit level of the culvert of 10.50 O.D. at its mouth in Wallasey Bridge Road.
20. Messrs John Taylor & Sons, in 1931, however, recommended the method. They suggested the provision of sluice gates at the entry of the Great Culvert to prevent the reversal of flow, with a weir placed in a chamber at such a level as to prevent the liquid of the Great Culvert rising appreciably above the soffit and that the pumps should deal with the overflow from such a weir from the Great Culvert as well as flood waters from the Cut itself, the Great Culvert being considered as a sedimentation tank as well as a storage tank.
21. In February 1932, Sandford Fawcett & Partners in their comments on Messrs John Taylor's report, reaffirmed that such a scheme would be open to the same objection and pointed out that the proposed weir would only be a few inches below the soffit of the Culvert and there would not be sufficient head to discharge the overflow liquid quickly enough to prevent flooding in Birkenhead unless an impracticably long weir was constructed. These reports are available to the Committee in full, if desired.
22. It is roughly computed that a storm on the 1,570 acres of Birkenhead would fill the Culvert right to its soffit level in some 50 minutes. Plainly, unless relief is given, reflux valves are impracticable.
23. When back flow from the Great Culvert to the Open Cut does occur it is, in my opinion, due to a variety of circumstances, either in sequence or coincidental.
24. I do not think it is possible to calculate under what precise circumstances such back flow would occur, and to what extent any dilution would be effected. Both must vary considerably, and be dependent upon a large number of factors, such as the following:-
(i) the amount of storm water subsequent to rainfall dependent on the times of concentration from the River Birket and its tributaries, and any storm water already present in the Culvert;
(ii) the incidence of storm water run-off and foul flow through the combined sewerage system from the built up portion of Birkenhead;
(iii) the variation of tide lock periods, dependent upon the difference between spring and neap tides;
(iv) the effect of flow entering from the Fender Valley sewer.
25. All these, to a greater or lesser extent, determine the extent and effect of foul flow and the degree of its dilution by storm water.
26. One must also consider the possible effect of reflux valves on the lower reaches of the Fender Valley Sewer. This enters the Great Culvert some 500 yards from Wallasey Bridge Road, and takes a considerable amount of foul and storm flow from a large area of Birkenhead, Wirral, Bebington and Wallasey. It has recently been duplicated from the Wirral boundary near Barnston as far as Upton, where holding tanks are being constructed. These will retain all storm flows which the lower lengths of the Fender Sewer are incapable of discharging.
27. If reflux valves were constructed at the mouth of the Great Culvert, escape therefrom might be up the Fender Valley Sewer. Dependent upon the levels attained, it might, during periods of complete closure, escape through the existing overflow at School Lane, Bidston, back into the River Birket.
28. Though it is impossible to say without very involved investigation, such a flow backing up the Fender Valley Sewer might have repercussions on mechanism controlling the Upton tanks, causing them to fill before it was absolutely necessary, and so overflow into the Fender Stream, as well as increasing pumping periods. This is a point of view upon which the Committee might well seek the opinion of their Consultants, Messrs Sandford Fawcett & Partners.
29. The Great Culvert is, in reality, the life line of much of Birkenhead's sewerage system, both in the built-up area south of the Docks and the whole of the Fender Valley drainage area. This latter includes Prenton, Upton and the Woodchurch Estate. Not only large areas of the residential property, but works and industries depend upon the Culvert sewage outlet, either directly or by connecting sewers.
30. To deal with this problem, the Cheshire River Board have, with their Consultants, Sandford Fawcett & Partners, considered the scheme for pumping from the Great Culvert by a proposed pumping station at Morpeth Dock into the River Mersey.
31. At the Conference held on April 29th, 1953, the Engineer to the Cheshire River Board stated that ultimate figures had been considered and this scheme would suffice for many years, and that no supplementary scheme would be required, other than, possibly, the construction of higher or wider flood banks to increase the storage capacity of the lower reaches of the Birket and certain inlets into it.
32. Birkenhead, as a constituent authority of the Cheshire River Board, will pay their share towards the loan charges in respect of such a capital scheme, which would be reflected in the precept levied by the Board on the County Borough. They are entitled to claim, in my opinion, that their financial liability shall be limited to the basis of rateable value upon which the precept is assessed. By such precept, they, in common with all other constituent authorities of the Cheshire River Board, contribute in that rate towards all capital works, maintenance and administration throughout the whole of the River Board's area of jurisdiction, which contains 730 square miles, and which extends to the borders of Knutsford, Macclesfield, Stoke-on-Trent, Whitchurch and Chester. These towns lie just outside its perimeter.
33. I am not au fait with the details of the Morpeth Dock Scheme, as this is being designed by the Cheshire River Board as a statutory authority.
34. It would appear that one of the reasons for the scheme is to enable the main rivers to be so treated as to accommodate the run-off and so obviate flooding in Hoylake, Wallasey and Birkenhead. This will bring more water more rapidly to the Great Culvert.
35. I am assuming that the present discharging capacity of the Great Culvert can deal adequately with the maximum flow after such treatment of the rivers has been carried out when a free outfall is available at low water. Naturally, any pumping station at the outlet mouth of the Great Culvert can only pump the amount of flow which the Great Culvert itself is capable of discharging at that point for the plain reason that any pumps can deal only with the amount supplied to them. The pumping station will, presumably, therefore maintain the maximum discharging capacity as if a free outlet were always available.
36. If this presumption is correct, there will be no likelihood during tide lock periods of any hydraulic head building up within the Culvert and causing the back flow into the Open Cut. The Mersey Docks & Harbour Board are aware of this scheme, as they refer to negotiations for the land required at Morpeth Dock.
37. It is difficult to understand the reason for their writing to the Ministry in respect of a matter for which a solution has been sought for a great number of years, and which now, apparently, has entered a period of fruition.
38. The Dock Board's letter to the Ministry may raise the question as to the use of the Great Culvert for the sewerage of the North End of Birkenhead. This has long been a point of contention. It was the subject of a report by the Town Clerk of Birkenhead, Mr. Alfred Gill, on the 10th October, 1888.
39. It may be of use if, whilst not considering the position legally, it could be considered from a historical and engineering standpoint.
40. The "Hundred of Wirral", by W.W. Mortimer, states that in 1845 there were upwards of 100 streets in Birkenhead and Claughton. The ordnance sheet for 1844 shows a considerable amount of Birkenhead south of Wallasey Pool had been laid out and, to a large extent, developed. Amongst the streets which had been constructed and which lie within the area now draining to the Great Culvert were the following:-
Argyle Street 850 yards long
Beckwith Street 1,920 yards long
Bidston Road 1,100 yards long
Cavendish Street 500 yards long
Cleveland Street 2,350 yards long
Conway Street 3,400 yards long
Hamilton Street 670 yards long
Price Street 2,700 yards long
Park Road East 560 yards long
Park Road West 900 yards long
Tollemache Street 1,900 yards long
Vittoria Street 650 yards long
Cathcart Street 650 yards long
Eldon Street 300 yards long
Bridge Street 1,050 yards long
Brook Street 1,500 yards long
Camden Street 600 yards long
Canning Street 1,000 yards long
Claughton Road 1,900 yards long
Exmouth Street 490 yards long
Grange Road 650 yards long
Park Street 470 yards long
Pool Street 200 yards long
Watson Street 490 yards long
41. A considerable amount of development had, therefore, taken place in the years previous to 1844.
42. The Great Culvert was constructed in 1845/6. All this development, therefore, had taken place before the Docks were constructed and had their outfalls to the Wallasey Pool. A report of the Surveyor to the Commissioners on 2nd January 1849, does, in effect, refer to the "entire discharge of the several outfalls to the North District takes place at Woodside Beaching Basin through the medium of the Dock Company's sewer and their several junctions with it along the course of the "Wallasey Pool", viz: Tollemache Road, Gilbrook, Vittoria and Bridge End". (See Appendix 'B')
43. This report also draws attention to the fact that the shores of the river and estuary were freely open to the natural and artificial drainage of the township at any point along the coast prior to the execution of the sewer.
44. The Road and Improvement Commissioners, who administered the development of Birkenhead until incorporation of the Borough in 1877, maintained that not only did the Great Culvert intercept outfall sewers when it was constructed, but also that it was constructed partly for this purpose.
45. Arising out of conditions placed by the Dock Board (which took over the duties of the Dock Commissioners in 1858), on the grant of permission for the drainage of certain land in Beaufort Road into the Great Culvert, the Improvement Commissioners passed the following resolution on September 4th, 1866:-
"That a letter be addressed to the Board pointing out that the Great Culvert or Sewer running under Beaufort Road and in Corporation Road was constructed for receiving the sewage of the Town as well as for carrying off the drainage waters of the Bidston Marshes and that in fact the sewers and drains which formerly discharged into the pool are now connected with the Culvert and several new Sewers from time to time, which would have had their outlet into the open pool if the Culvert had not been made, now empty into that Culvert and that there is no doubt that many new sewers will hereafter be made which must necessarily be connected with the Culvert."
The Clerk to the Commissioners also wrote to the Secretary of the Dock Board on 5th August, 1866, as follows:-
"I am desired by our Road Committee to point out that it was constructed as well for the reception of the sewage of the Town as for carrying off the water from the Bidston Marshes which formerly flowed into Wallasey Pool. All Sewers in Birkenhead which formerly discharged into Wallasey Pool and the Sewers subsequently constructed which would have had their outlet in the Pool, if communication with it had not been interrupted by the Great Culvert or Sewer, not empty themselves into the Culvert, and as new drains and sewers are constructed in that district they will necessarily be connected with that Culvert".
46. It is, therefore, clear that the Culvert was utilised by the Dock Commissioners as a sewer from its inception.
47. The Great Culvert was constructed under the Birkenhead Dock Act, 1844. It has been contended that under Sections 125-135 of this Act, the Dock Commissioners were empowered to construct the culvert and that its purpose was the carrying of the water from the area above Warrington's Bridge which then usually flowed through the Wallasey Pool.
48. I draw attention to the joint opinion expressed by Sir Lynden Macassey, KC, and Mr. R.W. Montgomery, K.C., upon questions affecting this matter put to them by the Cheshire County Council in December, 1929. This being legal interpretation, the matter will be dealt with by the Town Clerk.
49. If this is legally indisputable, then it would appear that the whole of Birkenhead lying south of Wallasey Pool, which at the time of the construction of the Great Culvert was partially developed, was by inference deprived of all its sewage outfalls and no alternative facilities provided.
50. It is suggested that even if Birkenhead had not been developed and had been merely agricultural land, it is difficult to understand how that natural drainage could have been cut off for the construction of the Docks and no other method of drainage given.
51. There are further historical factors which imply that the Great Culvert was considered a sewer. For example, there is reference in a letter dated 10th October, 1866, from the Clerk to the Commissioners to the Dock Solicitor to a memorandum dated 24th February, 1866, written upon a plan agreed to and signed by the Engineer of the Dock Board and the Surveyor to the Commissioners. This letter states that the memorandum and plan expressly admit the Culvert to be also a township sewer.
52. The provision of the marginal sewer on the north side of the Docks in the County Borough of Wallasey is interesting.
53. It was constructed about 1859 by the Mersey Docks & Harbour Board, possibly under the Birkenhead Dock Act 1844 and is maintained by the Dock Board at their own expense.
54. Wallasey Improvement Act, 1867, Section 8, refers to the construction of this sewer, and states that it was for the purpose of receiving the drainage which would otherwise have flowed into the Pool converted into a dock, and gave permission to Wallasey - at that time a Local Board - to discharge all or any part of their district at such points or places as they may from time to time require.
55. About 1902, the Fender Valley Sewer was constructed by the Wirral Rural District Council. This entered into the Great Culvert some 500 yards from the entry of the Open Cut which, at that time, was near the old Birkenhead boundary. It was brought 333 yards through Birkenhead down to a point below the connection from the Graving Dock.
56. This was done under the authority of the following agreements:-
(a) On 23rd March 1891, Birkenhead and the Dock Board entered into an agreement setting out the conditions under which connections to the Culvert should be allowed in future. This included a charge of 5/- per annum for each, and imposed on Birkenhead the liability to pay one half of the cost of maintenance.
(b) A further agreement between the same parties dated 9th June, 1902, permitted the Corporation to connect the Fender Valley Sewer, including the specific right to Birkenhead to drain sewage from Oxton, and to the Wirral Rural District Council to drain the Fender Valley district..
(Note:- The Dock Board considered this was essentially a matter for the Corporation, notwithstanding that the Fender Valley Sewer was not to be constructed by them, as it was a connection within their area.)
The agreement also increased the Corporation's share of liability for maintenance from 1/2 to 3/4.
(c) Pursuant to the above, an agreement between Birkenhead and the Wirral Rural District Council was signed on the 7th July 1902, giving authority to the Rural District to construct the sewer for 333 yards within Birkenhead, for a payment of £4,250 by Birkenhead to Wirral for the sewerage of Oxton (varied by a supplemental agreement dated 21st May 1906), and for the payment by Wirral to Birkenhead of the extra 1/4 cost of maintenance of the Culvert imposed upon them by the agreement of 9th June, 1902.
57. Thus, the entry of the Fender Valley Sewer might be considered as further evidence that it was regarded as a sewer; otherwise, no such permission would have been granted.
58. As stated in paragraphs 26 and 29, the Fender Valley Sewer itself serves an extensive drainage area which includes Upton, Woodchurch Estate, Prenton, as well as large areas of the Borough of Bebington, Wirral Urban District and a small area of Wallasey County Borough.
59. It is understood the Mersey Docks & Harbour Board ceased discharging waters from the Graving Dock round about 1930.
60. As far back as May, 1847, Mr. J.M. Rendel, in evidence, stated that - "it (the Great Culvert) was also of great importance to Birkenhead as a sanitary measure". (Mr. Rendel was a Consultant Civil Engineer called in by Liverpool Corporation in 1843 to suggest a plan for the employment and conversion of Wallasey Pool to establish a port and docks at Birkenhead.)
61. Section 21 of the Dock Commissioners Act of 1847, 10 & 11 VIC.Cap.264, also made provision for an alteration in the size of the Great Culvert.
62. Mr. J.M. Rendel, in his evidence on 3rd May, 1847, referred to the fierceness of opposition to the earlier (1844) Act, and to the fact that the Dock Commissioners were required to make the Great Culvert larger in diameter.
63. In evidence in the House of Commons on the Birkenhead Docks Bill on 27th May, 1856, he again referred to this enlargement as follows:-
"It (the Great Culvert) was to carry off the whole of the land-water of the marshes and the district above Wallasey Pool to the extent of about 12,000 acres, and the landowners compelled us to make that so large under the idea that their lands would not be adequately drained if we did not do so; we cannot drain into the float; the culvert was made pretty nearly at the level of low water. There is not much water in the summer, and unfortunately they make it a sewer.... etc."
64. It is not now clear as to the extent of the enlargement referred to, or who were the land owners concerned. The latter part of the quotation suggests that there were landowners interested in land at that time ready to be developed, and that the Dock Commissioners were forced to recognise the function of the Culvert as a sewer.
65. Birkenhead Corporation was incorporated in 1877 and are successors to the Improvement Commissioners. They merely continued the rapid development which the Commissioners had commenced. Today, the area affected is one of the most densely populated areas of the County Borough.
66. The Town Clerk, Mr. Gill, in his report was of the opinion that as far as he could see, he presumed that the Corporations were entitled to connect their drainage, from a part of the Borough at least, with the Great Culvert, but it was perhaps questionable if the Corporation would be authorised in permitting interference by or on behalf of an individual with the sewer, at all events without intimating their intention to the Mersey Docks & Harbour Board.
67. From a purely engineering point of view, it is difficult to see how else the Commissioners could have acted. At the time the Docks were built, all the land south of the Wallasey Pool was partly built and laid out, with sewerage outfalls. Docks are constructed which necessitate the cessation of those facilities.
68. The Great Culvert is constructed, and if it is argued that it was exclusively for waters from above Warrington's Bridge (see paragraph 47), then many years' work in developing and laying out Birkenhead prior to its construction was left without any provision for sanitary facilities, which can hardly be credited. The alternative would have been to construct another culvert alongside the Great Culvert, purely for the purpose of draining that portion of Birkenhead from Wallasey Bridge Road to Woodside. This, in effect, was what did happen on the Wallasey side, with the difference that the Great Culvert was constructed on the south side in Birkenhead.
69. Any questions arising out of the entry of sewage and storm water into the Great Culvert is, presumably, one for the Dock Board to consider and, if there is any question of pollution of the River Birket from the Great Culvert, it is a matter between the Mersey Docks & Harbour Board and the Cheshire River Board.
70. I attach two appendices as follows:-
Appendix 'A'. Sketch plan showing the position of the Great Culvert, the Open Cut and other features referred to in this report.
Appendix 'B'. A list of existing sewer connections to the Great Culvert.
71. I desire to acknowledge the assistance of the Deputy Borough Engineer & Surveyor in the considerable historical research which this report has entailed.
Borough Engineer & Surveyor.
LIST OF SEWERS CONNECTED TO THE GREAT CULVERT.
Wallasey Bridge Road 21"
Ilchester Road 3'-6" x 2'6" (Probably that referred to in para. 42 as "Tollemache Road".)
Bucchleugh Street 12"
Fender Valley Sewer 4'-0 x 2'8"
Beaufort Road 12"
Beaufort Rd / Corporation Rd 3'2" x 2'8" (Probably that referred to in para. 42 as "Gilbrook")
Cavendish Street 3'3" x 2'2"
Corporation Road 9"
Duke Street 3'-0" x 2'4"
Livingstone St. 6'9" x 4'6"
Berner Street 3'6" x 2'4"
Vittoria Street 4'9" x 3'6" (Probably that referred to in para. 42 as "Vittoria")
Vittoria St/ Hilbre St. 9"
Hilbre Street 12"
Neptune Street 9"
Cathcart Street (N) 3'6" x 2'6"
Cathcart Street (S) 12"
Pool Street 12"
Rendel Street 4'-0" x 2'-8"
Lord Street 6'-6" x 4'4" (Rendel St or Lord St probably that referred to in para. 42 as "Bridge End")
Intercepting Sewer under Railway Goods Line. About 4'-0" diameter
Taylor Street 9"
Between Lord Street / Sandford St 2'-6" x 1'6"
In addition to the above, there are a number of gulley connections and connections from individual premises, many of which have been done under the authority of the 1891 Agreement.