AiGUST 28, 1903.] 



SCIENCE. 



281 



THE WATER SL PPLY OF HAVANA, CLBA. 



Until recent years the water supply of 

 Havana came from the Almendares Eiver. 

 During the nineties the present water works, 

 deriving the entire supply from large springs 

 at Yento on the south bank of the Almen- 

 dares Eivers, was completed. The Vento 

 Springs and the covered aqueduct leading 

 its waters under the Almendares River and 

 into Havana are the pride of the city of 

 Havana which has erected au imposing monu- 

 ment to the engineer by whom the work was 

 conceived. The Vento Springs are surround- 

 ed by masonry walls sloping outward from 

 the springs except on the side nearest the Al- 

 mendares River, where they are vertical. The 

 surface water running down the slopes of the 

 masonry is caught in a gutter which dis- 

 charges it into the Almendares. At the top 

 of the masonry and some distance removed 

 from its margin another gutter catches the 

 surface water of the region sloping toward 

 the springs and discharges this also into the 

 Almendares. The water flows direct from 

 the spring into the covered aqueduct. The 

 provisions for maintaining the water in its 

 original purity from the time it issues from 

 the ground till it is discharged, either into 

 the reservoirs near the city or direct from 

 the faucets in the city, are ideal. 



There has been some speculation as to the 

 origin of the water issuing from the spring at 

 Vento. The water is beautifully clear and 

 rather warm, having a temperature of 26° 

 C. at the time of our visit. The Almendares 

 River, flowing but a few feet away, also has 

 clear water except after heavy rains, and its 

 water at the time of our visit was slightly 

 colder than that of the springs. It is pos- 

 sible that the Vento Springs derive their 

 water from the upper courses of the Almen- 

 dares, though this is so highly improbable 

 tiiat the suggestion may be left out of con- 

 sideration. The springs being situated on the 

 south side of the lower course of the Almen- 

 dares, the region across the river— that is the 

 region north of the river — may be excluded as 

 a po.ssible contributing source of the supply 

 "f the Vento Springs. The region about the 

 springs is composed of coralline rock. In 



such porous material conditions under which 

 territory on one side of a river may contribute 

 to springs located on the opposite side of a 

 river are impossible. 



The most probable origin of the Vento water 

 supply can best be understood after a general 

 statement of the conditions of the surrounding 

 region. 



The southern slope of the provinces Guana- 

 jai, Havana and Matanzas is largely drained 

 by underground streams. The streams ari- 

 sing in the hills and mountains, forming 

 the watershed between north and south drain- 

 age, run above ground for a distance and then 

 disappear underground. The Ariguanabo 

 River thus runs into a bank at San Antonio 

 de los Bafios and disappears among fallen 

 rocks. A few yards away from its '' sumidero ' 

 the water can be seen running in its under- 

 ground channel through an opening in the thin 

 roof of the channel. A few yards further on 

 a dry cave leads down to the water, which 

 at the end of the dry cave disappears among 

 fallen rocks. Other rivers disappear in a 

 similar manner. They can not be followed 

 in their underground courses because they 

 completely fill them. The underground waters 

 and the channels in which they run can, how- 

 ever, be reached in places through sink-holes. 

 The streams reappear, in part, at least, in a 

 number of ' ojos de agua,' some near the 

 coast south of San Antonio. The region 

 drained by underground streams is compara- 

 tively flat, with frequently no indications of 

 surface streams and their erosion, and ex- 

 tends westward to near San Cristobal where 

 the first permanent surface stream is ob- 

 served. At Artemisa and Candelaria stream 

 beds contained pools of water in March, 1902. 



From San Cristobal to Pinar del Rio there 

 are many small perennial streams. Eastward 

 from San Cristobal the cave region has an 

 unknown extent. Poey limited it to the juris- 

 diction of Guanajay, but it certainly ex- 

 tends as far east as the meridian of Matan- 

 zas and from reports probably beyond Cien- 

 fuegos. East of Rineon there are, however, 

 frequent river beds, all but one of which were 

 dry during the time of our visit. This main 

 cave region belonging to the southern slope 



