X, A, 2 Heise: Water Supplies in the Philippines 139 



well at Bauan, Batangas, drilled to a depth of 298 feet, which flows 250 

 gallons per minute 18 inches above the ground surface at high tide, and 

 50 gallons per minute at low tide at the same elevation; in other words, the 

 flow at high tide indicates an increase of 400 per cent over the flow at low 

 tide, notwithstanding the fact that analyses of water samples collected at 

 both high and low tide give identical results and show the water to be 

 potable and free from salt-water contamination. 



In many borings, especially near the coast, brackish water 

 is encountered during the first 30 to 70 meters, even though 

 fresh water may be found at low levels. In some rather excep- 

 tional cases, in which salt water was encountered at great depths, 

 continued drilling developed a supply of fresh water. At 

 Wright, Samar, salt water was found at 180 to 215 meters ; this 

 was cased off, and drilling was continued. At 312 meters fresh 

 water was found under sufficient pressure to cause a flow, which, 

 although slight even at ground level, did not cease entirely at 

 12 meters above the earth's surface. 



The deep-well waters are so lacking in uniformity that gen- 

 eralizations regarding them are difficult, if not impossible, at 

 the present time. Very frequently wells drilled within a few 

 meters of each other may encounter entirely different strata, 

 and the water from them may be markedly different. Two 

 wells drilled on the Bureau of Science grounds within 75 meters 

 of each other are very different, both in regard to the water- 

 bearing strata from which their supplies are derived, and the 

 quality and quantity of water encountered. Well 1 runs 725 

 parts per million total solids and 70 parts chlorine ; well 2 runs 

 500 parts total solids and 12 parts chlorine. Three wells in 

 Iloilo (at the Iloilo Electric Company's works), located within 

 about 15 meters of each other and drilled to about the same 

 depth, show similar irregularities, two being approximately 

 similar but differing from the third. 



The minimum temperature of deep wells drilled in the low- 

 lands is about 28° C, but the temperature range is great. 



The deep-well waters range in total solids content from about 

 120 (well 129, Nueva Caceres, Ambos Camarines) to 8,200 parts 

 per million (Janiuay, Iloilo), and in chlorine content from 1.5 

 (San Jacinto and Binalonan, Pangasinan) to 4,471 (Janiuay, 

 Iloilo) . 



The highest free ammonia content recorded is that of a well 

 at Los Baiios, Laguna, 70 meters deep, which showed 32.7 

 parts per million. The reason for this abnormal content is not 

 apparent. 



