All possible data have been collected as to the amount of water actually used by the municipalities of the island so that they might serve as a basis for the design of new works. As few of the towns use meters (and none of them have the entire supply metered) it is difficult to get precise facts. The average per capita consumption per day ranged from 60 liters (16 gallons) in Guayama, where there is a shortage of water and the people can use it only from 8 a. m. to 4 p. m., to 130 liters (34 gallons) in San Juan and Arecibo. Both of the last-named places have meters in very general use, although they were not introduced into Arecibo until 1913; it was found that their use reduced the consumption of water from 370 liters (98 gallons) to 130 liters per capita per day.

From two years' pumping records of the San Juan works, it is found that the maximum daily use of water is liable to be 25 per cent greater than the average, and the maximum hourly use may be one-third greater than this maximum. As the use of water is bound to increase with the more extended introduction of sewers and plumbing, an average consumption of 150 liters (40 gallons) per capita per day is believed to be a safe assumption in designing new works. The size of the main pipe line supplying the town, however, must be sufficient to deliver water at the maximum hourly rate which is one and one-fourth, one and one-third, or one and two-thirds times the average rate; this means 250 liters per day on the given assumptions. In addition to the above, the pipes must have sufficient capacity for fire service. In Porto Rico the number of fire streams necessary may be taken at twice the square root of the populaion tin thousands and the average rate of consumption of a fire stream is 1,000 liters per day. In the smaller and poorer towns it is believed these rates would be excessive and that an average per capita consumption of 100 liters per day would be ample. If z is taken as the population of a town in thousands, the number of cubic meters required under various conditions may be stated as follows:

It will be noted that the rate necessary for fire service is so large that the amount needed for domestic use may be almost neglected, although the amount of water used at fires is insignificant as compared with the total for the year.

BUILDING CONSTRUCTION.

This service has no direct authority of law to pass on the safety of building construction, but this division on several occasions during the year refused to grant permits for buildings which might evidently become dangerous to the public. There seems to be no authority delegated to pass on such matters, and, as all building plans

necessarily come to this service, it is evidently the most economical place to do thẹ work. The large increase in reinforced concrete buildings, which are often designed by inexperienced persons, makes some such provision more necessary than formerly. Under present conditions the occurrence of serious accidents is only a question of time.

REPORT OF THE WATERWORKS OF CAGUAS, GUAYAMA, PONCE, AND MAYAGUEZ.

These investigations of waterworks were made by order of the director of sanitation, and are part of a comprehensive plan for obtaining detailed information of all of the water supplies of the island. It is the intention to take up the waterworks of other municipalities in the future.

Al

Caguas water supply.-Caguas is located directly south of San Juan, on the main road to Ponce, and is the center of the tobacco-growing district of the island. The increase in the population has been very rapid, amounting to 90 per cent between the census years 1899 and 1910, and the present population is estimated at 12,500. though the rate of increase in population is not likely to be maintained in the future, the water consumption is certain to be very much greater than in the past, owing to the fact that sewers are now being constructed. This will largely increase the use of plumbing fixtures, which have heretofore been comparatively few, owing to the impossibility of properly disposing of the waste waters, since the soil is an impervious clay.

The present waterworks of Caguas were built in 1907, when the population was about 9,000. They were designed on the basis of the daily use of 100 liters per capita with a future population of 12,000. Both of these figures are now exceeded after only 8 years of use, and an increase of capacity is urgently needed in the near future. The source of supply is a small stream southwest of the city, and it has sufficient water to supply the town for many years. The water is of good quality and the turbidity is generally low. It is noticeably below the average in oxygen required and in the amount of nitrogen content. The total number of bacteria per c. c. was the lowest of any of the waters examined (average, 339 per c. c.) and no B. coli were found. The watershed has steep hillsides, largely wooded; it extends about 6 kilometers in length above the dam, an average of a little over 2 kilometers in width, and has an area of about 15 square kilometers. The greatest width is about 4 kilometers. There are 3 schoolhouses, 160 dwelling houses, 24 tobacco sheds, and 4 small stores located on the watershed with a population of about 725, or 48 persons per square kilometer. The dam is a substantial masonry structure in good condition, but needs cleaning out. The reservoir should be duplicated and proper arrangements made for cleaning; this would enable the city to always have on hand a supply of clear water independent of freshets, and the water would have the advantage of some storage. At present there is no means of cleaning the reservoir without depending on the supply directly from the dam. The structure is of reinforced concrete, and is not covered; the walls are located almost entirely below the ground.

The present main pipe line is of cast iron 8 inches in diameter and is too small even for the ordinary consumption of water and entirely inadequate for fire protection. It is believed to be in good condition. If an additional main pipe were laid and provision made for good fire service, arrangements could probably be made with the fire insurance companies for a reduction in rates which would go a long ways toward meeting the interest on the cost of the improvement.,

The distribution system consists of 1,800 meters of 6-inch pipe, 3,225 meters of 4-inch pipe, and 2,100 meters of 2-inch pipe. There is also a considerable amount of still smaller pipe, so that it would be necessary to add largely to the piping to obtain a good fire service. The number of fire hydrants is 30.

Guayama water supply.—The city of Guayama is located near the coast in the southeast part of the island and is in an important sugar district. It increased 56 per cent in population from 1899 to 1910; the present population is estimated as 10,000. There is no sewer system and the soil is an impervious clay.

The present works were built in 1890 when the population was between four and five thousand and they have less than one-half the capacity required to-day. Plans have been prepared by the interior department for building a dam farther up the stream, remodeling the distribution system, and constructing a new pipe line. As the executive council has approved of the loan for the purpose, this work should be commenced in the near future.

The intake dam is located on the Aguamanil River, but this source is largely augmented by the discharge from the Carite Reservoir of the irrigation service which has a power house located a short distance above the proposed new intake. The Carite Reservoir has been in operation for only a short time, so that the water at present is not of as good quality as may be expected in the future when the vegetation within

the dam site has been cleared away. The amount of water is unlimited but must be procured from the irrigation service.

The present dam is too small and is not located at a sufficient elevation to furnish the water needed through the 5-inch cast-iron pipe line, which is in bad condition. By removing the intake farther up the stream the conditions will be much improved, since the population on the watershed will be largely reduced and the chances of contamination will be very much less.

The pipe line from the dam to the reservoir is of cast iron, 5 inches in diameter and 3,064 meters in length; it has been considerably reduced by tuberculation, and has much less capacity than when originally laid. The reservoir is a covered masonry structure with two compartments, with a total capacity of about 1,200 cubic meters. It is located just south of the town. The pipe from the reservoir to the plaza is 10 inches in diameter and 700 meters in length. The difference in elevation is 29 meters. The town is continually short of water for the reason that the 5-inch pipe from the dam to the reservoir requires 24 hours to fill one compartment of the reservoir, and this quantity of water is generally consumed by the city between the hours of 8 a. m. and 4 p. m.

Ponce water supply.-Ponce is the next largest city after San Juan and is located on the south side of the island. It increased in population about 25 per cent from 1899 to 1910. The present population is estimated at 38,200. The soil is sandy and underlaid with gravel, so that it is comparatively easy to dispose of the waste waters. The city, however, is badly in need of sewers, as the continual contamination of the soil is bound to be injurious to the health of the inhabitants.

The waterworks were built in 1876 and no alterations or improvements of importance have been made since that time, although many repairs have been necessary on the aqueduct, which is of masonry of horseshoe shape, a little more than one-half meter wide and about the same in height. This aqueduct closely follows the surface of the ground and is continually subject to damage from washouts, landslides, and roots of trees. It extends from the dam to the reservoir, a distance of about 3,000 meters. The reservoir is a covered masonry structure with a capacity of about 2,500 cubic meters. It is located at the north edge of the city about 400 meters from the plaza and 25 meters above it. There is no satisfactory way of cleaning the reservoir, as it has only one compartment, and the town can not be supplied with water if it is disconnected. The main pipe line is of cast iron 10 inches in diameter; a large part of the distribution system is of 2-inch pipe or less. A new dam should be built farther up the stream, a new cast-iron pipe line should be laid from the dam to a new reservoir to be located at a greater elevation, since much of the town is already too high to receive sufficient pressure from the present reservoir and future expansion should be in the same direction; a greater elevation is also necessary for proper fire protection. These improvements would practically mean the entire rebuilding of the works.

Mayaguez waterworks.-Mayaguez is located at the western end of the island. The estimated population in 1915 is 17,300; the rate of increase between 1899 and 1910 was only 9 per cent. There is no public system of sewers, although a few streets have sewers laid by private enterprise. The soil is an impervious clay. Plans have been made for a complete system of sewers, but the municipality has not procured the money for building them.

The waterworks are the oldest on the island, having been built in 1861. Many alterations have been made to them from time to time. The original aqueduct was of masonry, but is now replaced by a cast-iron pipe, part of which is 12 inches and part 10 inches in diameter. Some of the older pipe has the interior diameter reduced at least 1 inch by coatings. There are two reservoirs of masonry located near the town and each is divided into two compartments; one of the reservoirs is covered and the other is not. Both the reservoirs and the dam are at insufficient elevation to give proper pressure in the town or afford efficient fire protection. A new dam and a new reservoir should be built and the distribution system should be largely improved. The detailed reports of Assistant Engineers Lippitt and Font as to the conditions found at the works and on the various watersheds are attached hereto. They indicate with persistent emphasis the necessity of a frequent inspection of the watersheds to prevent nuisances and contamination and the close sanitary control of all industries carried on, such as those of tobacco and coffee, where comparatively large numbers of people are gathered during certain periods and proper sanitary conditions are conspicuously absent.

Analysis of waters.-A tabulated statement is attached hereto showing the main details of these water supplies and also a comparison of the average analyses of the water which were taken by the laboratories during the year.

9489°-WAR 1915-VOL 3- -9

ably safe.

NOTE.-The first column gives the average of all waters of the island, which are believed to be reason

Comparative statement of the main details of water supplies.

The intake of the Caguas water supply is located about 6 kilometers southwest of the town, taking water from the creek known as the Quebradillas. The land in the valley of the Quebradillas is used for pasture and for the culture of tobacco, sugar cane, bananas, and vegetables.

The valley is very well watered, and even in the driest season, has so much water that the part taken by the town does not make any noticeable diminution in the amount flowing on. The water is also notable because of the fact that it is very seldom muddy, and even after heavy rains clears up very rapidly. The rains are distributed more or less, throughout the entire year, though some of the months are much more rainy than others; one year rains were recorded on 262 days.

The main points to be taken under consideration in the sanitary survey of a water supply are the sources of contamination (actual and probable), the sources of purification, and the suitability of the supply for the present and future needs of the town. To get this information it is necessary to examine the territory draining into the stream above the point at which water is taken for the supply and to study the habits of the people living in this territory. It is also necessary to have a series of chemical and bacteriological analyses of the water during the different seasons of the year.

Contamination of water by washing of clothes.-One of the principal causes of the contamination of water in this supply comes from the washing of the clothes of those living on the watershed above the intake dam. It is, without doubt, the most dangerous source of infection during the dry season. Whenever possible the women who live in the rural districts go to some stream near by to wash clothes. This is partly because of the saving in labor, that would be necessary to carry water up from the stream to their houses, and partly because they prefer to wash in groups and talk while they work. Sometimes they will carry water from a neighboring spring, stream, or water hole, and wash their clothes near the house, generally in groups also. In such cases they

seldom change the place they have chosen to wash and throw the dirty water on the same place on the ground each time.

When washing is done in the river the dirty water is carried at once to the intake, the time of transit depending on the distance from the dam and the velocity of the stream. The dirty water from the clothes washed near the houses will not all go into the stream before being purified, as some of it will soak into the soil, but the rain will wash a part of it into the stream. If this dirty water were always thrown on a different place there would be much less danger to be feared because of it, but it is generally more convenient to throw such water on a certain spot which soon becoms contaminated. This contamination is often increased because the washing is done in the shade and the water is thrown where it can not receive the purifying effect of the sunshine and where it does not dry up readily.

Bathing. The people in the rural districts probably bathe about once a week. The boys, naturally, go in swimming more than once a week. The men bathe, as a rule, on Saturday afternoon, Sunday, or some holiday, and, when they own them, take their horses along with them to be washed. The women bathe when they finish washing and the younger children play about in the water or are bathed at the same time.

This bathing in the stream, while far from pleasant for the consumer, is probably not as dangerous as the washing of clothes, since the sick are not liable to bathe. The clothes of the sick are probably washed more frequently than those of the well, so that any failure on their part to bathe is more than counteracted by the washing of their infected clothes.

Fords. The watershed is covered with a network of paths going from each house to the trails leading from Cidra to Caguas or to some point along the Carretera. Many of these paths cross the Quebradillas Creek and more cross the creeks running into it. The trails that are used by more than one or two families always have puddles of mud and slime in some of the shaded parts. These puddles are seldom, if ever, dry and they are always to be found on both banks of the stream where cattle or horses are brought to or through the stream. It is unavoidable that a certain amount of this slime stick to the feet of the men and beasts crossing the stream or that a certain portion of it should be washed off and carried away to contaminate the water.

Cattle. Cattle do the greatest injury to the supply at their regular watering places. They are almost always taken to some place where they can wade out and drink. The place where they enter and leave the water is cut up by their hoofs and the mud formed there is carried by them into the water.

The animal often defecates or urinates while still in the stream, thus increasing the contamination of the water considerably. Owing to the length of time they are in the water when brought down to drink, more filth is washed from their legs and feet than when they are crossing the stream. They also stir up the mud that had settled on the bottom, adding that to the general contamination.

In many parts the pastures are so arranged as to allow the animals to get to the stream at will. This is injurious to the supply, as they either contaminate the water directly or leave their fæces on the bank of the stream to be washed into the water by the first rain that comes along.

Tobacco sheds.-The tobacco sheds are a probable source of infection because of the number of people working in or near the sheds during a short season each year, about two or three months. The number of people working in each shed varies from 20 to 30. As there are 14 large and 10 small tobacco sheds above the intake, this means that there are about 600 people employed in the 24 sheds.

There must be some place near each of these sheds where, having no latrine, the soil is highly contaminated and washed into the Quebradillas above the intake. This concentration of human wastes renders the water supply more susceptible to contamination, because it does not allow the soil to become purified sufficiently to absorb the dangerous matter.

These sheds should have some type of temporary latrine that could be filled in and disinfected when necessary or at the end of each season. A good latrine for this purpose is the trench latrine, similar to model plan No. 560 of this service. It consists of a portable shed and floor so arranged that when necessary a new trench can be made and the old one rendered harmless.

Road drainage.-There are about 3.8 kilometers of highway that drain into the water supply, 3.2 kilometers on the main road from San Juan to Ponce, and 0.6 kilometer on the road from Las Cruces to Cidra. Owing to the almost impervious nature of the road, almost all the washing goes directly into the stream. It would be possible to prevent some of this from going into the water supply by the construction of special ditches and culverts, but the cost would be excessive.