Martis, 28° die Februarii, 1860. Ordered, THAT a Select Committee be appointed to consider the Means of effectually REPORT. THE SELECT COMMITTEE appointed to consider the best means of effectually Cleansing the SERPENTINE; HAVE considered the Matters to them referred, and have agreed to the following REPORT: ; THE sheet of water called the Serpentine was derived from the Ranelagh Brook, which, after springing in the Hampstead Hills, ran along the Bayswater Valley through Kensington Gardens and Hyde Park, under the ancient Knightsbridge, into the Thames. The waters of this brook having been checked by the dam which was thrown across the lower end of the Serpentine in the reign of King William the Third, flowed into gravel-pits and ponds which were adjacent to their channel, and occupied their present area in 1730. As population increased in the districts through which the brook passed, it lost its character of a brook, and became known as the Ranelagh Sewer. Its current had become so offensive in 1834, that an Act of Parliament was passed to divert it from the Serpentine through a covered channel, and since that period, only the overflow in heavy or continuous rains has reached the Serpentine. This overflow is the main cause of the complaints which have been made of the state of the Serpentine, and constitutes such a nuisance as in our opinion ought to be immediately abated. The Engineer of the Metropolitan Board of Works has informed us that the Board are about to commence works for the purpose of intercepting all this sewage, and that these works will be completed before the end of the summer. When this is done, the main cause of the past deterioration of the water will be removed. The mud which has been accumulating for so many years covers the bottom of the lake to a thickness of nine feet in some places. It is black and partially semi-fluid, containing a large proportion of decaying organic matter, and is very prejudicial to those who, by accidents in bathing, skating, or otherwise, are immersed in it. The foulness of the Serpentine, which renders it so unfit to be the place of recreation for the multitudes of all classes and from all places who flock to the Metropolis, is attributable mainly to the following causes the occasional admission of sewage, the contamination arising from putrefying mud, the deposit of soot and other impurities of the London atmosphere, the results of bathing, and the stagnation of the water. The only correctives heretofore applied to the evils arising from these impurities have been,-the supply of a certain quantity of fresh water obtained from springs in the lake itself, the rainfall and water shed, and from the Chelsea Water Company. These, however, have not been sufficient either for removing obnoxious exhalations, or for clearing the water of confervæ and other vegetable productions; and during the summer months of 1858 and 1859, a quantity of quicklime was thrown into the water, by which, for a time at least, the evils complained of were diminished. Several plans and estimates have been submitted to the Government for remedying this evil condition. Sir John Rennie, in September 1848, proposed to remove the mud, and to obtain a supply of fresh water from the water companies, or from the Brent or the Verulam; Mr. Mann proposed, in November 1848, to cover the mud with concrete in the manner which was subsequently adopted with regard to St. James's Lake in 1857. Messrs. Easton & Amos, in 192. December 1848, proposed also to cover the mud with concrete, and they submitted another project, in April 1857, for supplying water to the Serpentine from a well in Duck Island. In 1858, Mr. Page was instructed by the First Commissioner of Works to investigate the question, and in 1859 a plan was prepared by him which he stated would put the Serpentine into a clean and sanitary condition, and maintain it in that state, and also render it less dangerous to bathers and skaters. This plan received the sanction of the Government, and was submitted by them to Parliament. Owing, however, to a change of Government before the Civil Estimates were voted, the opinion of Parliament was not taken upon it, and Mr. Hawksley was requested, on the 7th July 1859, to prepare a scheme, which he submitted on the 15th of July, and which was adopted by the First Commissioner of Works. A sum of 17,000l. was voted by Parliament for its execution, and tenders were accepted on 25th November 1859; and although the works have made considerable progress, they are as yet incomplete. This plan was intended to purify the water by filtration, without dealing with the mud, and without any increase in the supply of fresh water. It aimed at removing the fibrous filaments of confervæ, the naviculæ, and other lower orders of aquatic vegetation, which occur in still water containing free carbonic acid or bicarbonate of lime, and which produce a disagreeable appearance in the water. This object was to be secured by causing the Serpentine to circulate through filter beds of sand, so that a 30th part of its whole bulk might pass daily through the filter during the six hottest months, a 60th during four of the colder months, leaving it at rest during the remaining two months of the year. This plan was recommended for its efficiency and economy, as enabling a larger quantity of water to be purified in this way than by any other means. But against this it has been urged that, in comparison with other schemes, its results will not be worth its cost, that the cleansing of filter beds close to public walks is likely to be offensive, that it will become unnecessary whenever a copious supply of water is obtained, and that the works necessary for its execution will be prejudicial to the appearance of that portion of Kensington Gardens where they are situated. Although river water drunk in towns is commonly passed through filters of sand on its way to the houses to which it is distributed, and although filtration is also used to purify water for some manufactures, yet no instance has been mentioned to us of its having been employed for the purpose of keeping a large body of water in a permanent state of purity, and we have received much evidence as to facts which might guide us in coming to a conclusion upon the probabilities of success which may attend such an experiment. The proposed filtration is not stated to be such as can remove impurities held in solution; and, considering that the object in view is not only to provide an ornamental piece of water, but a bath in which many more, than those who, in the present repulsive condition of the water take 260,000 baths yearly, may seek health and recreation, your Committee are of opinion that the common mode of supplying a lake with fresh water, is preferable to the new and ingenious contrivance of refiltering continuously even a larger annual quantity than can be supplied from a well or a river. If a supply of fresh water sufficient not only to replace the waste, but to provide for a continual change, were impossible to be obtained; in the absence of another alternative, filtration might be justifiable; but your Committee believe that such a supply of fresh water may be obtained from the springs within or contiguous to the Serpentine, from an enlargement of the watershed of the Park and Kensington Gardens, and from other sources which have been pointed out to the Committee. Some of this supply may be obtained by means of simple gravitation, at a small expense. Conflicting evidence has been given as to the quantity and quality of the water that can be pumped from the well in Duck Island; but Mr. Hawksley states in his evidence, that he entertains no doubt that a considerable supply of water water can be procured in the neighbourhood of his works, and that an increased amount of water could be drawn into the Serpentine by an extension of the surface drainage of the Park and Kensington Gardens. We have had, however, a more embarrassing task than to decide merely whether Mr. Hawksley's plan is the best for effectually cleansing the Serpentine. We have had to consider whether that plan, recommended by great engineering authority, adopted by the Executive Government, sanctioned by Parliament, and nearly approaching its completion, is so unsatisfactory in its object and means that it ought to be arrested, even in its present stage of advancement, and the work which has been performed diverted to other purposes. After much patient investigation, we have arrived reluctantly at the conclusion that the proposed filtration will not be effectual for the desired object; and that this cleansing process ought not to be carried on in one of the most beautiful spots of Kensington Gardens. We recommend, therefore, that the project of filtration be abandoned, and that the best available supply of fresh water be poured in, to such an extent as to produce some continual flow. Whenever the Metropolitan Board have completed their works for the diversion of sewage from the Serpentine, measures should be taken for rendering the bed of the lake clean and hard. We have not come to any conclusion as to the extent to which the mud ought to be removed, hardened, or covered, nor as to the relative merits of gravel or concrete as a covering, nor as to the expediency of burning it, nor as to the depth which would best promote the convenience and safety of bathers and skaters, and the purity of the water; but we are of opinion that the present condition of the bed of the Serpentine absolutely requires amendment. 30 March 1860. |