For labor and material required in the installation of a drainage system in the city of Hot Springs, to care for storm waters from the mountains on the Hot Springs Reservation, $237,840. The sewerage system in the city of Hot Springs appears to be such as to require early measures looking to the betterment thereof, and I therefore commend your favorable consideration to the report herewith transmitted, to the end that the appropriations necessary for the completion of the work be provided by Congress. Respectfully, WALTER L. FISHER, Secretary. The SPEAKER OF THE HOUSE OF REPRESENTATIVES. DEPARTMENT OF THE INTERIOR, The honorable the SECRETARY OF THE INTERIOR. SIR: I have the honor to transmit herewith a report by Mr. J. W. Barnett, consulting engineer of this survey, entitled "Existing Sanitary and Storm Sewer Systems in the City of Hot Springs, Ark., and Hot Springs National Park, with Plans for Improvement.' Very respectfully, SLEDGE TATUM, Geographer. Through the Director and the Chief Geographer (R. B. M.) United States Geological Survey. Approved, January 16, 1913. GEO. OTIS SMITH, Director. Mr. SLEDGE TATUM, Geographer in Charge, Rocky Mountain Division, Washington, D. C. DEAR SIR: I have the honor to submit herewith my report setting forth the conclusions reached after an investigation of the sewerage and drainage systems of Hot Springs, Ark., said investigation being made in conformity with your requirements and under a commission issued November 1, 1912. On visiting Hot Springs I made a careful inspection of the city and territory immediately adjacent thereto for the purpose of familiarizing myself with the conditions effecting the problems to be solved. During this visit I secured such information as was available and outlined the work to be done by the field party in order to secure such additional data as was needed to complete the investigations. A number of records and maps were obtained from the city engineer, which were of great assistance in compiling this report. The field work intrusted to Mr. R. W. Berry, of the Geological Survey, was completed in a thorough manner and with great dispatch. From a petition submitted by the Business Men's League of Hot Springs to the Secretary of the Interior, dated December 20, 1911, I learn that the things complained of chiefly are the insanitary conditions resulting from a defective and inadequate sanitary sewer age system and the inconvenience and discomfort occasioned by overflows from the surface drainage system. The reports submitted with the petition and the results of my personal investigations afford abundant evidence as to the truthfulness of the contentions on the part of the citizens of Hot Springs. For the purpose of simplifying this report, I have decided to treat the subjects under consideration separately. The information pertaining to the sanitary sewerage system having been secured first, I have given this precedence over that of the drainage system. SANITARY SEWERAGE SYSTEM. The earliest reports on sanitation in Hot Springs indicate an effort on the part of the municipal authorities to have Hot Springs Creek serve the purpose of a sanitary sewer. The foul condition of the stream later led to a partial discontinuance of this practice and to the construction of a separate system of sewers, though very limited in extent. From these mains laterals have been laid from time to time until a greater portion of the residence and business sections of the city have been sewered. I attach hereto a map of the city showing the sanitary sewerage system as it exists, together with the proposed improvements. From an inspection of this map it will be seen that Hot Springs is located in the midst of mountains and small hills, which form a number of separate watersheds or drainage areas, for each of which has been planned independent systems of sewerages. It will be noted, however, that these several subordinate watersheds are grouped in such a way as to effect complete drainage by the use of only three out-fall lines. The main, or central basin, embraces that portion of the city bordering Hot Springs Creek and lying between Pleasant Street on the east and East Street and Violet Street on the west. The east basin lies to the east of Pleasant Street and the west basin to the west of East and Violet Streets. The sewerage from east basin is allowed to flow into Gulpha Creek. The outfall for the central and west basins is in Hot Springs Creek at a point 5,490 feet south of the city limits. Here the flow of the stream in any weather is not sufficient to dilute the sewage and prevent deposits of putrescible matter on the edges and bed of the stream, from which arise offensive odors. It is rather unfortunate for the city that it has been necessary to provide two separate outfalls, for the conditions in Gulpha Creek, in the course of time, will be as great a menace to the community adjacent thereto as is Hot Springs Creek, necessitating the establishment of two purification plants, or extension to Ouachita River. An investigation of several mains and laterals reveals the fact that the system has been planned without regard to the future growth and development of the city. As all evidence of this fact the main sewer leading from the business district to the outfall in Hot Springs Creek is only 12 inches in diameter. Into this main is allowed to flow all the sewage from the central basin, together with the hot water from the springs. At times this sewer is surcharged, and during heavy rains operates under pressure sufficient to force the manhole covers out of place. There is evidence of foul conditions in a number of mains due to insufficient fall and lack of proper flushing. Stoppages occurring in house connections indicate improper construction there also. The municipal authorities, it seems, have not exercised customary supervision over the construction of the sewers, the work having been left to the discretion of the persons taking the initiative in the improvement districts in which the sewers have been laid and to the plumbers and drain layers in general. This practice is to be deplored and should be discontinued. The enactment and enforcement of suitable plumbing laws governing the inspection of sewers during construction will insure good results. This work should be placed in the hands of the city engineer, which official should be required to make the necessary inspections and to keep a record of the sewers as laid. In addition to the defects noted, it appears as if the laws requiring the use of sanitary sewers are not being strictly enforced, and that sewage, both water and the surplus hot water from the springs, are being discharged into the arch under Central Avenue, all of which contribute to the nuisance complained of. This practice should be discontinued and the archway kept free from sewage and hot water. The surcharging of the sewers during heavy rains indicates the admission of roof water into the sewers, If the rains could be relied upon to come at regular intervals the problem of flushing would be solved, but, unfortunately, there may be weeks without rain. Roof connections should be discontinued and connection made with the drainage system. A number of automatic flush tanks have been provided at the dead ends of laterals, but their use has been discontinued on account. of the expense of operating them. I have attached hereto a print of a flush tank of an excellent design, which, if properly installed and provided with a water gauge on the supply pipe, can be operated at a very low cost, owing to the small flow of water required to set the siphon in action. There are a number of short lines on steep grades that can dispense with flush tanks, but the mains of the several subdivisions of the watersheds should be flushed at certain intervals, since the flow of sewage in them is not sufficient to make them selfcleansing. In designing a system of sewers there are several things to be taken into consideration before deciding upon the plan to be adopted. The principal points to be considered are the size of the town, its situation with reference to the disposal of sewage, the compactness of its buildings, its topography, its water supply, the sanitary habits of its citizens, and its financial ability. In this instance the duty of the engineer is that of revising rather than planning, hence it becomes necessary to adopt certain features that would not have been employed had the work been planned in its entirety. The planning of the revised portions, however, is controlled by the conditions above set forth. The population of Hot Springs is so fluctuating that it is impossible to determine with any degree of accuracy the quantity of sewage to be provided for. A recent census gives a fixed population of 15,000. The indications are the city will have a steady growth in her permanent population and that in 20 years there will be an average of 60,000 people there. The inhabitants of Hot Springs are dependent to a great extent upon the floating population, and as a consequence the absence of manufacturing enterprises is noticeable, hence it will not be necessary to provide for trade wastes in the sewers. But the flow from the hot spring must be cared for, which necessitates provision being made for a much greater quantity of sewage than the daily consumption of water would indicate. It has been estimated that the combined flow of these springs amounts to 827,000 gallons per day. The reports of the water company indicate a daily consumption of 50 gallons per capita. It is a well-established fact that there is an hourly, daily, weekly, and monthly maximum rate of discharge of water consumed, the maximum hourly draft frequently amounting to 100 per cent in excess of that indicated by the average daily consumption. Therefore, it will be necessary in this case to plan for twice the mean daily water consumption and for the combined flow of the springs. Circular sewers should be so proportioned as to size throughout the system that the depth of ordinary daily flow will be sufficient to prevent deposits. The transportive power of circular sewers of small diameter is dependent on the depth of flow in a great measure, as well as on grade, and velocity necessary to prevent deposit in sewers is variously estimated from 2 to 3 feet per second. My experience is that unless special means are employed to prevent deposits the following may be taken as minimum velocities and grades: Six-inch sewers, 147 feet per minute; fall, 1 in 200. It will not be necessary in planning the proposed improvements to use as light grades as the minimum, since a fall of at least 1: 200 can be had in every case. In future extensions, however, due consideration should be given the grades in question, and none used less than those indicated. The above estimates do not apply to house connections. The minimum grade for these should be 1: 48 and the minimum size for terra-cotta drains 6 inches. The extent to which 6-inch sewers have been used to serve the purpose of mains is unusual for a system of this size. The better practice is to employ nothing smaller than 8-inch pipe for mains and 6-inch for house connections, since the chances of obstructions occurring in 4-inch house connections are much greater than in lines 6 inches in diameter. The ventilation of sewers is very important. This is usually effected by the use of perforated manhole covers and house connections. The problem at Hot Springs differs from that of other cities in that the hot water from the baths and springs flowing through the sewers forms a vapor which if allowed to escape by way of the manholes at the street level would be unsightly and unpleasant. Therefore, it will be necessary to dispense with the perforations in the manhole covers in the mains carrying hot water, and dependence placed in the house connections which extend from the sewer unobstructed to the roof. Having outlined in a general way the existing conditions, it remains to devise means by which the defects shown can be remedied and the nuisance complained of abated. There is but one course to pursue in attempting to relieve the congested conditions found in the mains of the central district, and that is to provide larger ones. It has been shown that the existing 12-inch main from Valley Street to the outfall is inadequate at times, and the 10-inch main along bathhouse row is being taxed, which if required to carry all the water from the baths and springs would be surcharged. It is proposed to substitute for the 12-inch main and 24 inch mains; the 18-inch to extend from the intersection of Elm and Valley Streets along Valley Street to Grand Avenue, and the 24-inch main to extend from Grand Avenue to the outfall. For the 10-inch main a 12-inch will be substituted for that portion along Elm Street from Valley Street to Reserve Avenue. The 12-inch main along Elm Street from Valley Street to Grand Avenue will be allowed to remain. The other mains for which new ones are substituted will be abandoned on the completion of the new mains. The new mains on Elm Street and along the line to the outfall to be laid in the old trench and at such a depth as will enable the existing house connections and intersecting lines to be reconnected without altering the present grade. With the completion of the proposed improvements, I feel that the essential features of the system will be made ample and that the capacities of these mains will be sufficient for any conditions we can reasonably be expected to provide for. To illustrate, we propose substituting for a 10-inch main with a capacity of 1,641,600 gallons per day of 24 hours a 12-inch main with a capacity of 2,592,000 gallons, for a 12-inch main 18 and 24 inch mains with capacities of 7,128,000 and 10,346,400 gallons, respectively; all to be laid on a 1 per cent grade except the 24-inch, which will have a minimum grade of one-half of 1 per cent. With a view of abating the nuisance arising from the foul condition of Hot Springs Creek below the outfall, it has been suggested that the sewer be extended to Ouachita River, where a sufficient flow can be had to dilute the sewage. This plan would have been feasible had no changes been contemplated in this stream, but I am reliably informed that the water power below its junction with Hot Springs Creek is to be developed in the near future, and that a reservoir will be formed, the high-water line of which will extend to contour 420. The formation of this reservoir introduces a condition necessitating the treatment of the sewage before it is discharged into the stream. If the crude sewage is allowed to flow into this reservoir, the precipitation of the solids held in suspension will convert that portion of the reservoir which is now the creek basin into a septic tank, which in the course of time would become offensive and deleterious to health. It is therefore necessary to treat the sewage before discharging it into the stream. Domestic sewage of a similar composition is being successfully treated in a number of cities in this country and abroad, and we can find in these cities numerous examples with conditions quite similar to the one at Hot Springs, but none have had the experience of treating sewage containing such a large quantity of hot water. Since the successful operation of a sewage purification plant depends in a |