Property ot the Dep'l ot Municipal and Sanitary Engineering, University of Illinois. Cit\> of (tambribge RESOLVE OF THE CITY COUNCIL AND REPORTS OF THE CITY ENGINEER IN RELATION TO THE SEWERAGE OF THE CITY 1898 RESOLVE. CITY OF CAMBRIDGE. In Common Council, Aug. 6, 1897. Whereas, In the past year, the sewers in many sections of the city fail to work properly during a heavy rainfall. As a result, a large number of cellars have been flooded by the sewage backing in. This has caused an incalculable amount of injury and expense besides being a menace to the health of the occupants of the buildings. As this is a matter which should be remedied as quickly as possible, therefore be it Resolved, That the Committee on Sewers investigate into the cause that creates this nuisance and take the necessary steps which shall remedy it. Referred to the Committee on Sewers. Sent up for concurrence. Attest: EDWARD A. COUNITIAN, Clerk. In Board of Aldermen, August 6, 1897. Concurred. Attest: EDWARD J. BRANDON, City Clerk. Digitized by the Internet Archive in 2017 with funding from University of Illinois Urbana-Champaign Alternates https://archive.org/details/resolveofcitycouOOcamb REPORT OF CITY ENGINEER. Office of the City Engineer, City Hall. To the Committee on Sewers of the City of Cambridge. Gentlemen:—The accompanying resolve of the Common Council, dated August 6, 1897, and concurred in by the Board of Aldermen, and this same date referred to the Committee on Sewers, was by you referred to the City Engineer for investiga¬ tion and report. The complaints referred to in the resolve have been so numer¬ ous, and the locations of the troubles complained of are so vari¬ ous that the matter resolves itself into an examination of the whole system of the city rather than that of any special locality. It may be stated in the beginning that the sewage of a city is oidinarily roughly divided into two classes or kinds; sewage proper being the liquid refuse from houses, factories, etc., and storm and ground water. In Cambridge both classes are re¬ moved by the same conduits. The amount of house sewage as compared with the amount of storm water received from any district is so small that but little account is made of it in esti¬ mating the sizes for sewers necessary to take combined sewage and storm water. It is from storm water that by far the greatest trouble is experienced in its removal. In order that a better understanding of the matter may be had, a brief glance at the physical conditions of the City as it relates to its sewerage will be helpful. PHYSICAL CONDITIONS OF THE CITY. The total area of the City between the boundary lines and the Harbor Commissioners’ line on Charles River is about 4,315 3 acres. Of tliis ? 126 acres are included in the Charles River Parkway and 324.8 acres in the Fresh Pond Park or reservation; so that the total area of the city to be considered is about 3,864.2 acres. It should be noted that this large area is not intersected by any brook or water course into which any considerable amount of surface water can be discharged; the few which for¬ merly existed having long since been filled up and abandoned. Another feature which renders proper and efficient sewerage difficult is the very general flat character of much of the surface of the city. This will be shown more clearly by a reference to the accompanying map marked “A.” Of the 3,864.2 acres in the city, 1,645.3 acres are less than five feet above mean high water or grade 20.00. 1,012.4 acres are between five and fifteen feet above high water, and but 1,206.5 acres are more than fifteen feet above high water. The highest point in the City being 76.10 above mean high water. It is on the territory first mentioned as being five feet above high tide that most of the trouble from defective drainage oc¬ curs. Much of this land is not over three to four feet above the level of mean high water and lies at a considerable distance from the outlet at the river. Another important fact is the large area of flats which have been filled in on the shores of Charles River, necessitating the extension of sewer outlets at a very flat grade to reach a point at which sewage could be discharged into the river. Some portions of this low territory are 5,000 feet, or about one mile, from the nearest point at which sewage can be dis¬ charged. With the flat grades at which sewers in these districts must be laid it is apparent that good drainage is a difficult matter. The storm water from the elevated lands rushing down to seek an outlet through the long stretch of flat low land through which all of the outlets pass must, unless a very free discharge is given, be very likely to cause trouble. Still another fact which has an important bearing on this question is the very large and rapid introduction of rain water into the sewers from surfaces of roofs, streets and yards. The almost universal practice of connecting conductors from 4 roofs of all classes of buildings, especially the large roofs from apartment houses and factories situated mostly in the localities least favorably conditioned for the removal of the same, has operated to largely increase the liability of surcharged sewers and consequent flooded cellars. HISTORY. It may be of interest to glance briefly at the history of the sewers as they have been built in this city. Naturally the oldest and most thickly populated section of the city would be the first to require drainage. We find that in 1845, just previous to the incorporation of Cambridge as a city, the first public sewers were built in three streets, viz.: Pine Street, Austin Street and in Brattle Square. The following year sewers in Cambridge Street and Otis Street, East Cambridge, were constructed, and from that time to the present in every year but one, additional sewers were constructed, until on December 1st, 1896, a total length of 101,695 miles of sewers had been built in our streets, or enough to reach in a continuous line from Boston to Springfield. In the early days the sewers were built by the Superintendent of Streets; but little attention being given to line and grade, and in many cases the depth as well as size has been found very de¬ ficient for modern requirements. Very vague and indefinite records and plans were kept of the work done, and most of the information now available has been obtained since 1867. At that time the supervision of the sewers was put under the charge of the City Engineer and accurate and reliable plans and data concerning sewers constructed have since been kept. Prior to about 1870 very little experience or knowledge had been had of the proper construction and designing of sewers, es¬ pecially with reference to requisite capacity to properly drain a given area. Most of the information was obtained from the limited experience of English engineers, adapted for localities and rainfalls differing from many which obtain in this country. Eor some years now American engineers have had an oppor- 5 tunity to study the question under conditions existing in this country and very much valuable data has been obtained. It is found that many of the earlier rules and formulae gave results too small for many conditions and rainfalls in populous districts. PRESENT CONDITION. To December 1st, 1896, there were constructed 536,950 feet, or 101,695 miles, of sewers and 1,587 catch basins, besides a large number of manholes, lampholes, etc. The total cost of construction of these sewers is $1,252,304.09. From 1873 to 1896 the cost of maintenance and reconstruction, together with the cost of the various connections with the Met¬ ropolitan sewer, was $547,429.85, making a total expenditure for these purposes of $1,799,733.94. The city has been divided into sixteen districts or areas, as shown on the accompanying plan marked “B,” each having a separate connection with the Metropolitan sewer and each with an overflow or outlet for discharging storm water. Three of these outlets discharge into Alewife Brook and thirteen into Charles River. In addition, a small section of North Cambridge is drained in connection with an area in the City of Somerville into the Metropolitan sewer at Tannery Brook. As this is but recently built and is intended to take only a limited amount of storm water from roofs, no further reference will be made to it here. The sizes of these areas or districts vary greatly; the largest having its discharge at Binney Street has an area of 843.4 acres, and the smallest at Willard Street an area of 21.38 acres. The sizes of the sewers vary directly as the area drained and inversely as the inclination or pitch. The largest, Binney Street, is eight feet four inches high and eight feet wide. The smallest, Dun- ster Street, is twenty-four inches by twenty-four inches in di¬ mension. All the sewers are designed to take both sewage and storm water, discharging the first into the Metropolitan sewer and the latter into the natural outlets at tide water. The first serves for 6 ordinary or dry weather flow, the last serves for combined house sewage and storm flow. It may be well to correct an impression which seems prevalent, that the Metropolitan sewer is responsible for the increased trouble which has been had with the sewerage of this city since it went into operation. This idea is entirely wrong. The same outlets for the discharge of storm water still exist and are in op¬ eration. The Metropolitan sewer simply takes sewage under or¬ dinary conditions and removes it. In times of storm the min¬ gled sewage and storm water are discharged as before. The sewers as at present constructed are ample in capacity for the ordinary flow of sewage. It is only when this is augmented by heavy storms that trouble is experienced, and it should be borne in mind that it is not the storms in which the greatest total amount of rain falls that causes the most trouble, but rather a storm in which the rate of rainfall 1 is the largest. The high rate may continue but a comparatively short time and the amount of rain be small 1 . There is a remarkable variation in the seasons regarding the frequency of storms with a high rate of rainfall. In some years few or no storms will have more than a moderate rate, while occasionally in a single year several storms will occur with a rate of rainfall much above the normal. The present year seems to have been such an one. Since June there have been at least three storms in which an excessive rate of rainfall took place, causing great trouble in many parts of the City, almost entirely in that portion referred to on Page 4 as below grade 20.00. The same trouble has been experienced in the adjoining cities of Somerville and Boston. The variation in the rate of rainfall may be illustrated by a reference to the memorable storm of October 14th and 15th, 1895. Six inches of rain fell during this storm which lasted about thirty-six hours; at that rate the average rate of rainfall would be but one-sixth of an inch per hour, yet the total amount was enormous. On June of the present year more than one inch fell in a single hour, while the United States Weather Bureau reports that on July 7, 1897, at Brattleboro, Yt., 2.26 inches 7 fell in twenty minutes. At Chelsea, Vt., on July G, 3.68 inches fell in one hour. July 2d, at Southington, Conn., 2.1U inches fell in forty minutes. It is clear that to take the water collected by storms of this character would require sewers of enormous size and capacity and it is rarely attempted except for small areas. Just how much the sizes of an extensive system of sewers should be enlarged to provide for the flow occasioned by storms of this character, occurring only at intervals, has never been Anally determined. The most common practice has been to construct sewers of capacity to take the flow from a storm of one inch per hour, assuming that it takes two hours for this amount to reach the outlet. This has been the accepted method for many years and is the one by which until recently the sewers of Cambridge have been planned. The experience of the last few years would seem to indicate that sewers designed on this basis, and with the unfavorable conditions existing in Cambridge, are not of capacity sufficient to receive the water collected in storms of a high rate of rainfall, especially in districts situated so low as to be subject to the retarding action of tide water. The more complete occupation of land by buildings, especially large factory buildings, apartment houses, etc., and the very general connection of roofs with the sewer, the constant enlarge¬ ment of area occupied by streets, with a corresponding increase in the number of catch basins discharging large volumes of water into the sewers, have undoubtedly overloaded many of the sewers with water so that at times and under certain conditions, choking does take place with attendant evils of back water in low cellars and yards, and occasionally for a short time on the surface of streets. A very prolific source of trouble in this connection is the plac¬ ing of water closets, sinks and wash-trays with open waste pipes in cellars or basements. In by far the larger number of cases in which property has suffered from back water, it has made its entry through open fixtures in the cellar. This matter was fully referred to in a report of the City Engineer, dated December 2, 1895, on the condition of sewerage of certain streets in the vicin- 8 ity of Sidney street. There can be no doubt that very much less trouble would be experienced if all open plumbing fixtures were placed above the first floor. REMEDY. Having now at some length examined the physical conditions of the City with reference to the problem of the proper drainage of the same, also the history and present condition of the sewer¬ age system as constructed and now in operation, and finding that in some localities there is need of relief, a consideration of the question what steps can be taken to remedy the trouble and give the needed relief will be in order. Three methods of accomplishing this suggest themselves. First,—The construction of a number of new outlets or storm relief sewers, commencing at points in the various sewer districts at which choking fakes place, and extending by the most direct route to a discharging point at tide water; thus dividing the affected districts as at present laid out into a number of smaller districts with separate overflows for storm water. Second,—The entire method of drainage could be changed and a strictly “separate system ” of sewerage introduced. By this plan a complete system of small pipes and sewers would be laid in every street in the city, and in the case of wide streets two sewers, one at each side of the street, would be laid, and only sew age be allowed to enter. This system, carrying only sewage, would be connected at various points with the Metropolitan sewer, somewhat as at present, the sewage being cared for and removed by the State. All roof water, drainage from yards and street surfaces would be taken by independent drain pipes to the present sewers and discharged into tide water at the present storm outlets. By this plan two separate and distinct systems of sewers would be in operation at the same time and in every street, and so a perfect separation of house sewage from storm water be made. Third,—It seems possible that a combination of the two plans outlined above might be adopted. In certain low districts like the Binney Street district, where much trouble has been experi- 9 enced, and the general grade of land and cellars is low, a separate system might be introduced, leaving the old sewers as con¬ structed for surface water, and laying a new system of pipes for sewage only. In other and higher areas like the “Oxford Street district 7 ’ and the “Lowell Street district, 77 where the trouble has been caused not so much by the low grade of the land as by in¬ sufficient capacity, the first plan of constructing, as required, in¬ dependent storm relief sewers might be best, thus adapting as far as is possible the character of the remedy to the locality. The first plan would have the merit of simplicity. The pres¬ ent system of sewage to which the people and plumbers are ac¬ customed would be continued. Only such relief sewers as are found from time to time to be necessary would be built, but eventually a large expenditure will be necessary to meet the future requirements and replace sewers now small and imper¬ fectly laid. There is some uncertainty whether at times of high water and heavy rainfall there might not still be danger in low districts of back water. By the second plan, what is generally considered the most per¬ fect and satisfactory method of sewage from a sanitary stand¬ point would be adopted and which in our case would most surely prevent trouble from back water, etc., from sewers. On the other hand the first cost would be .very large, as practically the entire new system would have to be installed at once. This would not only entail a large expenditure for the City, but every house owner would have to make a separation of plumbing fix¬ tures ; one set of pipes taking the sewage and one set taking roof, yard and around water. It is nor unlikely, also, that an enlarge¬ ment of some of the present sewers for the purposes of surface drainage only would be necessary, as while the immediate danger of flooded cellars would be removed, water might still be held on the surface of streets and in back yards, to the detriment of health. By the third plan the danger of flooded cellars in the lowest districts would be reduced, as they would be comparatively inde¬ pendent of the effect of storm water on the sewers in the districts now most affected. Each plan has some advantages and some 10 serious defects. The matter is a very important one, and to de¬ termine which method will, on the whole, be the best for the city to adopt will require more study than I have yet been able to give it. Any scheme at all adequate will require a considerable expenditure of money and time to accomplish, and I therefore ask for more time in which to study the matter and to make a definite recommendation later. Respectfully submitted, L. M. HASTINGS, City Engineer. Cambridge, October 15, 1897. SUPPLEMENTARY REPORT OF THE CITY ENGINEER. Office of the City Engineer, City Hall', May 20th, 1898. To the Committee on Sewers of the City of Cambridge. Gentlemen:—On October 15th, 1897, the City Engineer pre¬ sented a report to the Committee on Sewers on the condition of the sewers in the City; discussing at that time the physical con¬ dition of the City with reference to the proper drainage of the same, the history and the present condition of the sewerage sys¬ tem, and suggesting briefly three methods by which relief might be obtained from the troubles which were found to exist in some sections of the City. Of the three plans then suggested it has seemed after a careful consideration of the subject that the third was on the whole the best and safest plan to adopt. USE OF PEESENT SEWEKS. The condition of the sewers of the City as at present con¬ structed is somewhat peculiar, and in some respects unfortunate, as regards their future use and adaptability. As will be noted farther on, many of them are of insufficient size to be used as storm drains without more or less enlargement or relief by the construction of additional outlets. Even with enlarged discharge capacity it is doubtful if in cer¬ tain low districts and under unfavorable conditions of tide and storm, trouble would not then be experienced. On the other hand, these sewers are totally unfit to serve the purpose of a separate system, being constructed of brick, many of them with loose or open joints, whereas the present practice 12 is to build sewers in a separate system as tight as is possible, so as to exclude all ground or surface water. Many of the sewers were constructed with very shallow depths, whereas the modern requirement calls for much greater depth than formerly. While small for the purposes of a storm drain they are very much too large for the purposes of a separate sys¬ tem. This excess in size may not at first appear objectionable, but experience has shown it to be highly detrimental to the proper working of a system of this kind, rendering it much more likely to become obstructed and to get in a foul and unsanitary con¬ dition. In the plans recommended, the utmost use possible is sought to be made of the old sewers, supplementing them where needed by enlarged or additional outlets, introducing where it seemed necessary a separate sewer system designed for future extensions, so as to secure the best present results with the least expenditure of money, and at the same time not conflict with any future change in plan looking to the complete introduction of a separate system for the entire City. INTRODUCTION OF SEPARATE SYSTEM. In considering the introduction of a suggested separate system of sewerage for the City, one of the important questions to be considered is the proposed future policy and requirements of the Metropolitan Sewerage Commission with reference to the follow¬ ing points: First,—The separation of sewage from storm water both at present and in the future. If at no distant day it is to be required that all sewage shall be separated from storm water or that all sewage shall be measured and the amount disposed of by the Metropolitan sewer made the basis of a yearly tax for this service to each city or town, it would have a very important bearing on the question of which plan should be recommended for this City in any contemplated im¬ provement. Second,—The regulation or control of the discharge of sewage into the Metropolitan sewer. If this is to be so arranged that at every storm the connection with the Metropolitan sewer is shut off and the discharge made into tide water as at present, but little advantage would be gained by adopting the plan of separation of sewage in the low districts for which it is proposed, as the flow in the separate sewers connected for a time with a combined sewer outlet subject to the action of tide and storm water as at present would, in this event, be almost equally affected by tide and storm. If, however, the separate sewer could be connected with the Metropolitan sewer without the liability of being shut off, and the flow into the Metropolitan sewer made continuous, a very great gain would be secured. Third,—The liability to interruption in the pumping of the sewage by the Metropolitan works. If the pumping is stopped, the Metropolitan sewer would fill up and the discharge from the City sewers would take place under similar conditions to that noted above. In order that there might be no misunderstanding in this mat¬ ter, the following communication was sent to the Engineer of the Sewerage Commission: [Copy.] Feb. 16th, 1898. Mr. William M. Brown, Jr., Engineer Metropolitan Sewerage Commission. Dear Sir:—I am now studying plans of certain changes to be made in a sewerage system for this City, and am contemplating recommending the introduction of separate systems taking little or no surface or rain water. There is a point about which I spoke to you a short time ago which is important, and that is the regu¬ lation of the sewage at its connection with the Metropolitan sewer. To be of much value in remedying the trouble under which some sections of the City now suffer, two things at least would seem to be necessary for the scheme of separation of the sewage. 14 First,—That the water in the Metropolitan sewer should not be allowed to rise to too high an elevation, as some of the cellars in the districts under consideration are quite low, and situated a good distance from the Metropolitan sewer. What I wish to know is in this connection, if it is proposed by the Metropolitan Sewerage Commission to keep the pumps in the Metropolitan system constantly in action, so that the water in the Metropoli¬ tan sewer will be constantly maintained at a low level. Before recommending any plan I wish to ascertain definitely what the policy of the Commission is to be in this respect, as the success or failure of the separate system as proposed would be de¬ pendent on the manner of maintaining the water in the Metro¬ politan sewer. Second,—As to regulation: I would like to know if there would be any probable doubt as to the City of Cambridge obtain¬ ing permission to connect sewers from certain districts with the Metropolitan sewer with a regulation so high that only the most extreme rise of water in the sewer would cause the regu¬ lators to shut, as of course at such times, with the regulator shut, the whole system would be subject as at present to the action of tide water, and so no benefit would be obtained by introducing a strictly separate system as proposed. I think you assured me verbally that there would probably be no difficulty in obtaining from the Commission consent to connections with the regulation as described, but before recommending any scheme I would be glad to have a more definite statement from you or the Commis¬ sion. Yours very truly, (Signed) L. M. HASTINGS, City Engineer. In answer to this the following under date of February 22d, 1898, was received: Metropolitan Sewerage Commission, Office of the Chief Engineer and Superintendent, 1 Mt. Yernon St. L. M. Hastings, Esq., City Engineer, Cambridge, Mass. Dear Sir:—Your note of February 15th, 1898, in relation to special connections with the Metropolitan System for “ separate system” sewers for low areas in the city of Cambridge was sub¬ mitted to the Metropolitan Sewerage Commissioners at their meeting Saturday, February 10, 1808. They instruct me to say . that they desire to favor the construction of separate systems of sewers as far as possible throughout the Metropolitan area. It will extend the life of the works, and reduce the cost of operation and maintenance. At some later date when the capacity of the system is reached it may be found necessary to require that all connections be from separate system sewers. It is the purpose of the Commissioners to continuously operate their pumping stations. They know of no occasion for interrupt¬ ing the service except very rarely and for very few days if at all for necessary repairs or the introduction of additional pumps. There is no reason to doubt that on proper application to the Sewerage Commissioners they would allow these special connec¬ tions to discharge into the Metropolitan sewer until it flows full. Four your own safety you would maintain overflows at high levels into the tide. Yours truly, (Signed) WM. M. BROWN, JR., Chief Engineer and Superintendent. From this it would seem to be the policy of the Commission to encourage and favor, and possibly in the future to require, the separation of sewage from storm water in municipalities now op¬ erating a combined system of sewerage. It would also appear that favorable conditions regarding reg¬ ulation might be secured and that the liability of interruption of the pumping is only such a contingency as might occur in the operation of any large works. CHARLES RIVER HAM. The proposed construction of a dam across Charles River has also an important bearing on the question of sewage disposal above the location of the dam, which is now proposed to be placed a short distance below Brookline Street. By this dam it is proposed to hold the water in the river about two and one-half feet below the level of mean high tide, or from four to five feet below extreme high tide. If the water in the river can be maintained at this level it will naturally aid the present sewers to discharge storm water, owing to the increased head thereby gained, as the capacity of a sewer must be rated not at its best condition, 1 e., when the tide is low, but at its worst, when the tide is high. Every foot taken from the elevation of high tide is equivalent to a similar amount added to the inclination of a sewer. Also, if the water is kept at a nearly constant level with a consequent very much reduced scour, and the shores of the river prepared with flat sloping gravel beaches as proposed, it would seem that the discharge of mingled storm water and sewage which will inevitably take place at times under the present system would be very likely to create offense and be objectionable, especially in the vicinity of sewer outlets. If this condition obtained in the river above the dam, as it seems not unlikely it might, it would be an additional reason which might be urged for the separation of sewage from storm water. If the separate system is introduced in sections of the City it would probably be best to make the new sewers laid serve as house sewers, and the present sewers serve for the removal of storm water. In that case it becomes an important matter to de¬ termine if the old sewers are large enough to serve as storm drains, and if not, to what extent they must be enlarged or re¬ lieved by additional outlets. RAINFALL TO BE PROVIDED FOR. As stated in the first report, dated October 15th, 1897, on this matter, until recently sewers have generally been designed so as to remove a rainfall of one inch per hour, assuming that one-half that amount reached the outlet during that time. Experience with sewers designed on that basis in this and adjoining cities has shown that this is too small a provision; sewers designed on this basis failing to remove the water rapidly enough. In a recent report on this subject the City Engineer of Somerville says: “The provision of increased facilities for dealing with the rain falling upon the city area is a matter of rapidly growing impor¬ tance. The number of complaints arriving from flooded cellars and similar inconvenience has steadily increased with each sue- ceeding storm, and much attention has already been devoted to the remedying of these undesirable and unsanitary conditions.” The recent reports of the Sewer Division of the City of Boston contains frequent reference to the complaints received from flooded cellars in many districts. In a recent paper by Mr. W. C. Parmley read before the Civil Engineers’ Club of Cleveland, Ohio, after a careful analysis of the various elements in the problem of properly designing sewers, and referring to some observations on the flow in certain sewers in that city, the author says: “What conclusions can be drawn from the foregoing observation? The first and most obvious is that notwithstanding the poor grades and sewer junctions in some cases, the usual formulas and unit volumes for run-off, at least as applied to Cleveland, are entirely too small.” In a recent very elaborate report on the “ Sewerage and Drain¬ age for the City of Baltimore” by the two expert civil engineers, Rudolph Ilering and Samuel M. Gray, in discussing the “Run¬ off from Storms,” they say: “In designing drainage works it is of greatest importance to ascertain the quantity of water per unit of surface, for the removal of which provision should be made. Underestimating this quantity and thereby making sewers, drains or other channels too small, would result in flooding streets and cellars, and damage to property. It must therefore be avoided. On the other hand, too great an allowance should not be made, as the sizes of the drains and other structures, and consequently their cost would be unnecessarily increased. The problem re¬ quires that a proper medium be maintained between the two ex¬ tremes.” The amount of rainfall which should be provided for as “the proper medium” is a quantity difficult of exact determination and about which the practice of different engineers vary greatly. In some of the reports above referred to a rainfall of four inches per hour is the amount recommended, to be provided for. In the report of the Sewer Division of the City of Boston for 1896, two inches rainfall per hour is recommended, while, as stated above, most of the old authorities give one inch rainfall per hour as the proper amount. After a careful study of the ex- 18 perience and practice of other cities, and the amount and inten¬ sity of rainfalls which sometimes occur in this vicinity, I am convinced that provision should be made in all sewers now built or remodeled, for the removal of two inches rainfall per hour, one-half of this amount reaching the sewer in this time. In all the investigations made for this report the latter quantity, two inches rainfall per hour, has been used. On this basis, as was to be expected, all the sewers were found to be of too small size; many of the older ones very much so. Most of the sewers situated on high ground and above tide water, while evidently too small for the future requirements when the land is more fully occupied, yet have given little or no trouble. In several of these cases where trouble has occurred an enlargement of the sewers has remedied the difficulty. In dis¬ tricts where the land is low, for the reasons before mentioned, I believe a separation of sewage from storm water is the best and surest remedy, even if ultimately the storm sewers have to be en¬ larged also. But the inquiry may at once be raised, if the storm sewers are too small, how soon will they need to be enlarged, even if a separate system is built? It may be answered that while eventually many of the main sewers undoubtedly will have to be enlarged or relieved, yet in the majority of cases this need not be done at present. The tak¬ ing out of cellar connections, and sewer pipes with low fixtures in the cellars, will remove at once the greatest source of danger from back water. The storm water sewers can then act under a greater head than if these connections were still made, and even if water stood in gutters on the streets for a short time, no danger would be likely to result and but a temporary inconvenience would be occasioned to the few people likely to be traveling at the time of heavy rain¬ fall, when only it could occur. It is hoped that by the construction in the districts requiring relief of a separate system and a number of new outlets for storm water, dividing the present districts into smaller ones, any fur¬ ther enlargement of the present sewers may be postponed some years. RECOMMENDATIONS. Having now referred to some of the general considerations re¬ lating to this matter, a more detailed examination of the plans recommended will be undertaken. The sixteen drainage areas or districts referred to in the report of October 15th, 1897, are known generally by the street in which the main or outlet sewer is built. Beginning at the most easterly one they are now known as follows:— Bridge Street district. Area, 115.00 acres. (In addition to this the storm water from 800 acres in Somerville are drained through this outlet.) Binney Street district. Area, 843.40 acres. (The sewage of these two districts is now taken to the Metropolitan sewer through one connection at Portland Street and Binney Street.) Talbot Street district. Area, 89.9 acres. (There is also a section of low land situated between the above districts the area of which has never been included in either, which will be sew¬ ered by a new outlet, containing 116.60 acres.) Pearl Street district. Area, 79.1 acres. Pleasant Street district. Area, 102.4 acres. Western Avenue district. Area, 120 acres. Oxford Street district. Area, 414 acres. Dunster Street district. Area, 23.2 acres. Murray Street district. Area, 69.1 acres. Bath Street district. Area, 229 acres. Willard Street district. Area, 21.4 acres. Sparks Street district. Area, 81 acres. Lowell Street district. Area, 267.5 acres. Concord Avenue district. Area, 279.7 acres. Spruce Street (now Rindge Avenue) district. Area, 403.9 acres. North Avenue (now Massachusetts Avenue) district. Area, 153.9 acres. Tannery Brook district (sewered by a separate system), 27 acres. BRIDGE STREET DISTRICT. Little or no complaint has been received of trouble on this district. Care will have to be exercised in building on the low, 20 flat territory south of Charles Street not to place cellars contain¬ ing plumbing fixtures at too low a grade. If at any time the need arises, a system of small separate sewers connecting with the existing separate sewer in Binncy Street can readily be laid. At this time no definite recommenda¬ tion for this district seems necessary. BPSTNEY STREET DISTRICT. The large size of this district, the very flat grades existing on a major part of it, and the general low level of the surface, are conditions which tend to make proper drainage difficult. Sewage starting at some of the more remote points in this district has to travel over 13,000 feet by a very tortuous route to reach an outlet. Considerable trouble has been experienced in many parts of this district, principally on Cambridge Street from the Boston & Albany Branch Railroad to Windsor Street (see petition of Purcell et al., Sept. 7, 1897,) and the vicinity; also the region including Washington, Pine, Cherry, School and Windsor Streets; also on Amory, Antrim and Fayette Streets, (see peti¬ tion of Howlett et al., Sept. 7, 1897, also petition of Dale et ah, Sept. 7, 1897); and in the region about Sidney, Brookline, Green and Pilgrim Streets, (see petitions of A. P. Clark et ah, June 15, 1897, and Horvall 1 et ah, July 6, 1897) and on Massa¬ chusetts Avenue from Brookline Street to Temple Street. Of the two methods already referred to, viz.: the enlargement of the present combined sewers or the construction of a system of separate sewers, the latter is the plan here recommended for this district. Fortunately the Metropolitan sewer passes through the central portion of the district by the route in Albany and Portland Streets. The sewer here is of ample depth and its location such as to render the introduction of a separate system of sewers as called for, and connection with the Metropolitan sewer at points as needed a very easy matter. Relief for the present sewers in discharging storm water can also be given by the construction from time to time, as needed, of storm water outlets to Charles River, dividing the district now so large into a number of smaller ones, each with a more direct outlet for the discharge of storm water. In addition to the con¬ struction of these outlet sewers it will probably be found neces¬ sary in the future to enlarge some of the existing sewers. If a separate system is constructed, it will of course necessitate all house owners connecting with the sewers to take into said sewer systems only house sewerage, leaving the roof, ground and cellar water to be carried to the present sewer by an independent pipe. While the sewers here proposed to be built are designed of a size sufficient to carry off all the sewage of the entire district as eventually they will be required; only such sewers are estimated as seem necessary to build at the present time. For Cambridge Street and vicinity a new connection with the Metropolitan sewer would be made at the junction of Cambridge and Portland Streets, thence a sewer would be laid on Cam¬ bridge, Marion, Porter, Jefferson and Harding Streets, and pos¬ sibly in Hunting and Willow Streets. The scheme proposed for Hampshire and other streets is this: One sewer should start from the regulator at present connecting with the Metropolitan sewer at Portland Street, corner of Binney Street, thence passing through Bristol Street, Hampshire Street and Cambridge Street to Fayette Street, with branches in Fay¬ ette, Antrim and Amory Streets. The size and cost of the Hampshire Street sewer will be con¬ siderably increased by making it the outlet for a part of the Oxford Street district, as will be explained in the section dealing with that district. At Washington Street a new connection would be made with the Metropolitan sewer, thence a sewer would be laid in Wash¬ ington Street to Columbia Street, with branches in School Street, Pine Street, Cherry Street and Columbia Street. In connection with the relief of the Sidney Street section, it is proposed to construct a new regulator connecting with the Met¬ ropolitan sewer at the junction of Pacific and Albany Streets, thence carrying a sewer in Pacific Street to Sidney, and in Sid¬ ney Street to Massachusetts Avenue, and in Pilgrim, Auburn, Franklin and Green Streets. 22 It is also proposed to build a storm sewer through Pacific Street and Robinson Street to Charles River, and at the same time put in the separate sewer which will be required when this land, now vacant, is occupied. This storm drain in Pacific Street may be extended to Brookline Street and Massachusetts Avenue to relieve those sewers now over-taxed with storm w T ater. The system here referred to has already been the subject of a report by the City Engineer, dated December 2d, 1895, and the matter is one of the most urgent of any now being considered. In addition to the district bounded by Massachusetts Avenue, Pilgrim, Brookline and Sidney Streets, the large tract of vacant marsh land between Pilgrim, Erie, Brookline Streets and the Boston & Albany Railroad has received a good deal of attention from the Board of Health, owing to its unsanitary condition. The construction of the sewers here proposed would largely improve these conditions and be in the line of the future devel¬ opment of this territory. The owners of the vacant land in question have signified their willingness to co-operate with the City in the construction of the necessary sewers by contributing a substantial sum toward its cost. The sewer in Broadway from Columbia Street to Lee Street is small in size and laid at various times with different outlets. Some complaints have been received from the locality near In¬ man Street of back water in cellars. At some time an enlarged combined sewer or a branch of the separate system should be laid from the junction of Harvard and Columbia Streets to Broad¬ way, thence in Broadway to Lee Street. For the further relief of this district it is proposed to construct a storm water sewer from the present sewer in Main Street at Burleigh Street through a new street called Claflin Street to Charles RDer. While this is being constructed a separate sewer would be laid in connection with it and extending to the new regulator to be built at the junction of Washington Street and Portland Street. Still further it is proposed to connect the' sewer in Harvard Street at Portland Street with the present large trunk sew T er in Portland Street at Hampshire Street by a new sewer in Portland Street between these points. By this connec- tion a long detour will be avoided in the route, and so a better and more rapid discharge given to the sewage. As these latter sewers are not proposed to be built now no estimate is made of the cost. The following is an estimate of cost of sewers recommended for this district arranged for convenience by groups: Cambridge Street Section. Cambridge Street—Warren Street to Webster Avenue, 1,060 feet. Marion Street—Cambridge to Jefferson Street, 300 feet. Jefferson Street—Warren to Harding Street, 550 feet. Porter Street—Warren to Harding Street, 580 feet. Harding Street—Cambridge to Porter Street, 500 feet. Warren Street—Cambridge to Porter Street, 450 feet. Total, 4,040 feet. Total estimated cost of above sewers, $11,720.00. Hampshire Street Section. Bristol Street—Portland to Hampshire Street, 867 feet. Hampshire Street—Bristol to Cambridge Street, 2,934 feet. Cambridge Street—Hampshire to Fayette Street, 238 feet. Fayette Street—Cambridge to near Broadway, 1,206 feet. Antrim Street—Cambridge Street to near Broadway, 1,276 feet. Amory Street—Hampshire Street to near Broadway, 1,161 feet. Total, 7,682 feet. Total estimated cost of above sewers is $31,000.00. Washington Street Section. Washington Street—Portland to Columbia Street, 1,620 feet. School Street—Harrison to Austin Street, 1,530 feet. Cherry Street—School to Harvard Street, 835 feet. Pine Street—School to Harvard Street, 940 feet. Columbia Street—Austin to Washington Street, 412 feet. Total, 5,337 feet. Total estimated cost of sewers as above, $15,000.00. Sidney Street Section. Bobinson Street—Sea wall to Albany Street, 1,810 feet. 24 Pacific Street—Albany Street to Sidney Street, 810 feet. Sidney Street—Pacific Street to Massachusetts Avenue, 1,573 feet. Pilgrim Street—Sidney to Brookline Street, 470 feet. Auburn Street—Sidney to Brookline Street, 500 feet. Franklin Street—Sidney to Brookline Street, 520 feet. Green Street—Sidney to Brookline Street, 540 feet. Total, 6,223 feet. Total estimated cost of sewers in this section, $80,000.00. This trunk sewer is so designed as to be extended in Pacific Street from Sidney Street to Brookline Street, intercepting the old sewer there, thence through Brookline Street to Massachu¬ setts Avenue, relieving the overburdened sewer in that street, a total length of 1,720 feet. The estimated cost of this extension of sewers in Pacific and Brookline Streets is $23,000.00. The large cost of the sewer recommended for this section is due to its large size, some of it being five feet six inches in diam¬ eter, much of it on piles, and to the fact that in connection with it one and sometimes two separate sewers are to built in the same structure. TALBOT STREET DISTRICT. Large tracts of unoccupied land in this district near its outlet and in the vicinity of Erie Street are low and flat and in bad sanitary condition. The construction of the sewer in Robinson street recommended will afford facilities of greatly improving the present condition there. The most of the occupied lands are at a higher elevation, so that as ye't little or no trouble from defective drainage has been complained of. As these low grounds are developed, extensions of this separate system here recommended will have to be made, with the necessary drains for removal of storm water by direct outlets to Charles River. At present no recommendation or estimate is made for this work. PEARL STREET DISTRICT.—PLEASANT STREET DISTRICT. No complaints have been received from either of these dis¬ tricts, and no recommendations are made. WESTERN AVENUE DISTRICT. The low area in this district bounded roughly by Massachu¬ setts Avenue, Putnam Avenue and Western Avenue, has long been troubled with defective drainage. The area is almost com¬ pletely surrounded by a high ridge of land which pours large quantities of water into this natural basin with great rapidity. This fact, with its low elevation, indicates the necessity for a separation of the storm water from sewage. It is recommended that a new connection be made with the Metropolitan sewer at Flagg Street and a separate sewer laid from this point through Elagg Street, Kinnaird Street, Bay Street, Howard Street, Green Street, Franklin Street, Hayes Street, Grigg Street, Magee Street, Dodge Street and Soden Street. As it will be necessary at some time to enlarge the outlet tak¬ ing the storm water of this district, or construct an additional one, it might be well while the deep cut is being made at Putuam Avenue, to build a section of this storm outlet which will be re¬ quired to relieve the old system by discharging a part of the storm water through this new outlet. The following is the schedule and estimate of cost of the sewers recommended for this district: Franklin Street Section. Elagg Street, 1,230 feet. Kinnaird Street—Putnam Avenue to near Western Avenue, 1,460 feet. Bay Street—Kinnaird Street to Green Street, 430 feet. Green Street—Bay Street to near Pleasant Street, 1,240 feet. Franklin Street—Putnam Avenue to Pleasant Street, 1,600 feet. Hayes Street—Putnam Avenue to Howard Street, 420 feet. Grigg Street—Howard Street to near Putnam Avenue, 480 feet. Magee Street—Grigg Street northerly, 500 feet. Howard Street—Kinnaird Street to near Western Avenue, 770 feet. Dodge Street—160 feet. Soden Street—360 feet. Yernon Street—100 feet. Total, 8,750 feet. Estimated cost of above sewers, $30,000.00. If a section of the storm drain should be constructed at the same time as the sewers referred to above, an additional sum of $5,000.00 would be required. OXFORD STREET DISTRICT. On much of this district no trouble has been experienced. There is a section situated south of Mt. Auburn Street, between Banks and Mill Street, from which some complaints have been received. It is recommended to construct a separate sewer sys¬ tem in this section. A part of this system when built can easily be taken into the regulator proposed to be built at Flagg Street in connection with the Western Avenue sewer district scheme, and the rest can be taken into the Metropolitan sewer at Plympton Street. As the need for relief in this section does not appear to be urgent, no estimate for these sewers has been prepared. Another part of this district situated near the Somerville line between Cambridge Street at Baldwin Street and Sacramento Street has been troubled somewhat. This territory is badly situated as respects sewerage, being surrounded on all sides, except at its natural outlet through Somerville, with high land. Three ways of reaching this region and affording relief are feasible. 1st.—-Enlarge the present trunk sewers through Plympton Street, College Grounds, Oxford Street and Kirkland Street, keeping the district as now, a combined sewer system. 2d.—Construct a separate system with a connection with the 27 Metropolitan sewer at Eliot Square, thence construct a sewer through Elarvard Square, Peabody Street, Kirkland Street to Baldwin Street, and in Oxford Street to near Sacramento Street, with laterals as required in connecting streets. 3d.—Construct a separate system with an outlet through the sewer as proposed to be built in Cambridge and Hampshire Streets to Portland Street at Binney Street. The main trunk sewers for this district would then start from the Metropolitan sewer in Portland Street, thence pass through Bristol, Hamp¬ shire, Cambridge, Baldwin and Holden Street, thence across private lands to Carver Street to Sacramento Street, with branches or lateral sewers in side streets as required. The estimated cost of plan No. 1 is $160,000.00. The esti¬ mated cost of plan No. 2 is $85,000.00. The estimated cost of plan No. 3 is $88,000.00. I recommend the adoption of plan No. 3 as on the whole the best, for the reason that this route to the Metropolitan sewer is more direct; it passes through streets less occupied and used for travel, and it reaches the Metropolitan sewer at a point nearer its outlet. Part of the streets would have to be dug up anyway for the sewer in Hampshire and Cambridge Streets. By the time the sewer for this region is required it will not be unlikely that the question of a dam across Charles River will be decided. If such a dam should be built it would be of great benefit to the present Oxford Street sewer, as by keeping the general level of water in the river low and preventing extreme high tides, the capacity of the present sewer to deliver water will be greatly in¬ creased, and with the low district at Banks and He Wolf Street connected with the Metropolitan sewer at Elagg Street and the second low district between Cambridge and Sacramento east of Oxford Street taken care of, it is expected that there will be no need to enlarge the present Oxford Street sewer for many years to come. The schedule and estimate of cost is as follows: Baldwin and Sacramento Street Section. Bristol Street—Portland to Hampshire Street, 875 feet. Hampshire Street—Bristol to Cambridge Street, 3,161 feet. Cambridge Street—Hampshire to Baldwin Street, 1,846 feet. Baldwin Street—Cambridge to Kirkland Street, 1,163 feet. Ilolden Street—Kirkland to Everett Street, 742 feet. Private land—Everett to Carver Street, 1,012 feet. Carver Street—531 feet. Magnolia Avenue—Baldwin Street to Myrtle Avenue, 610 feet. Myrtle Avenue—480 feet. Amory Street—1,161 feet. Antrim Street—1,276 feet. Fayette Street—1,206 feet. Hammond Street—670 feet. Howland Street—250 feet. Wendell Street—600 feet. Crescent Street—700 feet. Sacramento Street—822 feet. Total length, 17,108 feet. Estimated cost of above sewers, $119,000.00. From this should be deducted the cost of Hampshire Street section, estimated to be $31,000.00, leaving a net cost of $ 88 , 000 . 00 . DUHSTER STREET, MURRAY STREET, BATH STREET, WILLARD STREET DISTRICTS. Ho complaints from these districts have been received, and no recommendations are now made. SPARKS STREET DISTRICT. The most of this district is elevated land from which no com¬ plaints of defective sewerage have been received. An area lying- east of Buckingham Street is, however, rather low and flat, and numerous complaints have been received and several petitions presented for better sewerage. (See petition of Lizzie L. Jackson et al., Sept. 21, 1897, and others.) It is not recommended that a separate system be introduced at this time in the district. A simpler plan would be to enlarge and deepen the present sewer 29 ]h Sparks, Craigie, Buckingham and Parker Streets, a distance of 2,004 feet, for which the estimated cost is $20,000.00. LOWELL STREET DISTRICT. A few complaints received from the low section in the vicinity of Auburn Place. No plan of relief is suggested at this time. CONCORD AVENUE DISTRICT. Land mostly elevated and not thickly populated; few com¬ plaints received of defective sewerage. No change is recom¬ mended at the present time. RINDGrE AVENUE (FORMERLY SPRUCE STREET) DISTRICT.—MASSACHUSETTS AVENUE (FOR¬ MERLY NORTH AVENUE) DISTRICT. These two districts are so situated that any plan of relief will involve the combination of parts of the two, and so it will be best to consider them together. A part of this region lying south of the Fitchburg Railroad is elevated land with good grades; no trouble has been reported from this portion. Another large tract in the northeasterly corner has a fair elevation, but is extremely hat and with consequent slight grades. Occasional trouble has been reported of flooding in parts of this section, along Orchard Street, Tenny Street, on Massachusetts Avenue near Walden Street, and on Massachusetts Avenue near Brookford Street. Between these two sections is the valley through which passes the Fitchburg Railroad and which forms the natural route of the drainage for the southerly portions of these two districts referred to. In this valley more or less trouble has been had, as on Cogs¬ well Avenue, Cogswell Place, and on Sherman (formerly Dub¬ lin) Street, and Bolton Street. The westerly portion of these two districts is made up of the Clay Lands or “ Fresh Pond Mead¬ ows 7 ’ bordering on Alewife Brook, the final outlet for the storm water of the whole of this region. These Fresh Pond Meadows are practically at a uniform level, but little elevated above high tide in Mystic River, into which Alewife Brook discharges. The 30 distance from the outlet of the Rindge Avenue sewer to the Mystic River is 10,845 feet, or more than two miles. This Ale- wife Brook has a total drainage area of 3,451 acres, or nearly five and one-half square miles, of which 476 acres are in the Fresh Pond Meadows. The enormous area draining into this basin, the flatness of the grade in the brook forming its outlet,, and the distance from the point of discharge, are elements which render the prompt re¬ moval of storm water well nigh impossible. As a matter of fact, in time of much rainfall the meadows become one vast lake from which the water recedes but slowly. As this region is more com¬ pactly built upon and consequently the storm water is more rap¬ idly discharged into the lowest grounds, and with more of the low area, now vacant, occupied, the problem of the proper dis¬ posal of the storm water from this region, and its preservation in a sanitary condition, will become a very serious one. Even at the present time the condition there presents a serious obstacle to the proper working of the sewers discharging into the Alewife Brook. The storm outlet sewers in Massachusetts Avenue and Rindge Avenue are necessarily laid at so low an elevation that many times the tops of the sewers are submerged by water standing on the meadows for days at a time. Not infrequently the storm water coming down the sewers from the high lands bordering the valley above mentioned fills the sewers in Rindge Avenue and Sherman Street and overflows from the manholes near Bolton Street, flooding cellars and streets in that vicinity. The problem of the prompt removal of storm water from the meadows is so large, involving as it must the joint action in some form of Cambridge, Belmont, Arlington and Somerville, and possibly the large number of persons holding real estate there, that it does not seem likely that any early action will be taken in regard to it, so that any plan proposed for the relief of the sewers in Cambridge must be based on the present conditions as regards the disposal of the water at the outlets. Various plans have been considered, to all of which serious 31 objections can be made. There are two objects which are sought to be accomplished by any plan prepared. hirst.—The relief of the sewers in the valley from surcharging by storm water. Second.—The prevention of flooding of cellars in the district by sewer water. As stated before, the valley through which passes the Fitch¬ burg Railroad is the natural route for the drainage, and so it is recommended that a right of way be taken on the southerly side of the Fitchburg Railroad extending from Alewife Brook to Bolton Street in which to construct a large storm relief outlet to the trunk sewer in Sherman Street. This relief sewer can, at some later day when required, be ex¬ tended through Railroad Street and a right of way now held by the city to Cogswell Avenue and through Cogswell Avenue to Massachusetts Avenue, relieving the sewer there. Connections can also be made with sewers on the southerly side of the railroad when required. In connection with this storm relief sewer it is recommended to begin the construction of a separate system of sewers to finally include the whole of the section north and east of the Fitchburg Railroad. The main trunk of this system would start from the present sewer in Massachusetts Avenue, thence run through Massachu¬ setts Avenue to Cottage Park Avenue, thence through Cottage Park Avenue, Montgomery, Rindge Avenue, Sherman Street, Railroad Street and private land by a right of way held by the City, Cogswell Avenue, Massachusetts Avenue, Blake and Or¬ chard Streets, with such branches and connections as may be required in various side streets. This plan is the beginning of a complete system of separate sewers for this section, to be com¬ pleted as occasion may demand, discharging into the Alewife Brook Branch of the Metropolitan sewer at its crossing with Massachusetts Avenue. The schedule and estimate of cost for the sewers recom¬ mended for these districts are as follows: Storm Relief Outlet. Alewife Brook to Sherman Street, 3,225 feet. Estimated cost, $40,000.00. Separate System. Massachusetts Avenue to Cottage Park Avenue, 733 feet. Cottage Park Avenue and private lands, 745 feet. Montgomery Street, Harvey Street and Rindge Avenue, 1,4GO feet. Sherman Street, Rindge Avenue to Bolton Street, 1,400 feet. Railroad Street and private lands to Cogswell Avenue, 1,973 feet. Cogswell Avenue to Massachusetts Avenue, 756 feet. Massachusetts Avenue, Cogswell Avenue to Somerville Ave¬ nue, 2,073 feet. Hadley Street, 300 feet. Blake Street, Massachusetts Avenue to Orchard Street, 430 feet. Russell Street, 250 feet. Orchard Street, Russell Street to Davenport Street, 1,250 feet. Tenney Street, 350 feet. Miller Avenue, 300 feet. Beech Street, 600 feet. Allen Street, 270 feet. Davenport Street, 600 feet. Mead Street, 380 feet. Ring Street, 250 feet. Cogswell Place, 400 feet. Walden Street, Mead Street to Massachusetts Avenue, 650 feet. Creighton Street, 800 feet. Regent Street, 700 feet. Richdale Avenue, 900 feet. Bolton Street, 900 feet. Total length, 18,470 feet. Estimated cost of above sewers, $79,600.00. 3 SUMMARY. Binney Street District: Cambridge Street section, 4,040 feet, cost . . $11,720.00 Hampshire Street section, 7,682 feet, cost . . 31,000.00 Washington Street section, 5,337 feet, cost . . 15,000.00 Sidney Street section, 6,223 feet, cost . . . 80,000.00 Pacific and Brookline Street extension, 1,720 feet, cost. 23,000.00 Western Avenue District, 8,750 feet, cost . . 30,000.00 Oxford Street District, 9,426 feet, cost . . . 88,000.00 Sparks Street District, 2,004 feet, cost . . . 20,000.00 Bindge Avenue District and Massachusetts Avenue; ' Separate system, 18,470 feet, cost .... 79,600.00 Storm relief, 3,225 feet, cost. 40,000.00 Totals, 66,877 feet, cost.$418,320.00 The estimated cost of the works as given above is believed to be a liberal one, no attempt being made to give a close or small esti¬ mate. It is believed that the actual cost of construction will not exceed the estimates, and perhaps a saving may be made. In the scheme as outlined, it is proposed to construct sewers on rhe separate system in the lower portion of the city where trouble has been experienced with the present sewers, together with such storm relief sewers as may be necessary; leaving the remaining districts with high and better natural facilities for drainage to continue on the same plan as at present. When the natural growth of the city, or the necessities of the Metropolitan System require a change in any or all of these sec¬ tions, they can then be made without any difficulty, the plan rec¬ ommended being elastic and progressive in this respect. Some practical difficulties due to the partial introduction of a new and somewhat unfamiliar system will undoubtedly occur and have to be met. The increased cost of plumbing and drains to holders of real estate may be objected to by some. In view of the superior san¬ itary conditions and the immunity from danger of flooded cellars and back water from sewers obtained by this plan, it does not 34 seem that this should have much weight; also some confusion may for a time occur among drain layers and others due to there being two sewers in some streets and only one in others. Some difficulty may be experienced in keeping the separate sewers clean and free from clogging, as but a limited use of them will at first be made. This can be overcome by a proper system of cleaning and flushing. The plans accompanying this report and marked “C,” “I),” “E,” “F,” “G,” show the route of the sewers by districts as herein referred to. Kespectfully submitted, L. M. HASTINGS, City Engineer. 35 ;• ,)\i. ; ; \ :'j -vi '• *i . ■ t.q: :■>[.{ < ■ : .. f < ■ D1 398430512