X. A, 2 Heise: Water Supplies in the Philippines 149 



it has occasionally been made an excellent water supply, notably 

 in the city of Iloilo, where a number of properly constructed 

 cisterns are giving good results. 



At Capiz, where the surface supplies are uniformly bad and 

 well drilling has resulted in failure, the construction of a cis- 

 tern large enough to supply the residents of the city with drink- 

 ing water is being contemplated. 



WATER SUPPLIES OF MANILA 



The problem of adequately supplying the city of Manila with 

 water is still troublesome, and funds for making improvements 

 are not available. It appears to be extremely difficult to impound 

 sufficient water at Montalban to last throughout the year, due 

 in a great measure at least to leakage, which the decomposed 

 and water-worn character of the limestone formations at the 

 site of the dam makes unavoidable. For the last two years it 

 has been necessary to supplement the Montalban supply with 

 water from Mariquina River, a proceeding which has proved 

 a serious menace to public health. The total storage capacity 

 is too small to allow of much sedimentation, and as no provision 

 for filtration has been made, water which is still carrying vary- 

 ing amounts of suspended matter finds its way into the city 

 mains. Large quantities of foreign substances are thus allowed 

 to accumulate in the pipes, and the attempts to purify the v/ater 

 with chloride of lime are seriously interfered with. During 

 the period in which chlorination has taken place, the water, as 

 examined at various points in the distributing system, has shown, 

 with increasing distance from the chlorination station, first a 

 marked decrease in bacterial count and frequently the absence 

 of amoebse and colon-group bacteria in 2 cubic centimeters of 

 samples of water, then a gradual rise in count, and the reappear- 

 ance of the organisms mentioned. Day after day the bacteria 

 count at the Bureau of Science tap has been in excess of that of 

 the water at the reservoir, although, at intermediate points, the 

 bacterial count has been exceedingly low. Frequent flushing 

 out of the distributing system is undoubtedly of great benefit, 

 but in itself is not enough to cause much improvement. In the 

 absence of reservoirs large enough to ensure adequate sedi- 

 mentation, a rapid sand filter, with proper equipment for pre- 

 vious coagulation whenever the water is turbid, is an imperative 

 present necessity. 



