of /IDejico's Bratnaoe, 269 



milco, Texcoco, Xaltocan, San Cristobal, and Zumpango. Each of 

 these lakes is fed by streams which have little volume during the dry 

 season, but which in the rainy season swell to considerable size, and 

 at times overflow the valleys. The lake of Zumpango was the most 

 dangerous of these, for it received the waters of the Cuautitlan River, 

 a river draining a large area of country, and having during the rainy 

 season a great volume of water. This river has been turned into the 

 cut of Nochistongo, and has ceased to threaten Mexico and its environs 

 with its overflow. 



From these topographical conditions frequent floodings of the old 

 Aztec city and of the Spanish capital, situated almost at the lowest 

 point of the valley, were sure to come in times of unusually heavy 

 rains. In early days, when the Aztecs lived in the middle of Lake 

 Mexico, when their temples and wigwams were built on piles and the 

 streets were often only canals, the periodical overflows from the upper 

 lakes were a matter of small concern, though even then the Nahua 

 engineers were called upon to protect the city by dikes. But when by 

 evaporation, by filling in at the site of the city, by lessened waters, due 

 to the fissures caused by earthquakes, Lake Mexico had disappeared, 

 and the city had come to be built on the spongy soil, above all, when 

 the short-sighted choice of Cortez had been confirmed and the capital 

 of New Spain had come to stand on the ruins of the Aztec town, 

 increasing rapidly in population and wealth, it became a serious 

 matter that on an average of once in twenty-five years the streets 

 should be from two to six feet under water for an indefinite time. 



Work done by the Spaniards. From 1519 to 1553 the Spaniards 

 were busily engaged in building Mexico, and another grand dike, 

 similar to that built by Netzahualcoyotl in 1450, was formed around 

 the city; this protection proved insufficient, for in 1580 another inun- 

 dation took place. The Viceroy of the day, Senor Don Martin 

 Enriquez de Almanza, assisted by engineers, engaged to find an outlet 

 for the waters north of the valley. During the time they were thus 

 engaged, important facts were gleaned respecting the River Cuautitlan, 

 and its curious behavior at the foot of Nochistongo, whence it doubled 

 its course at a certain altitude and ran toward Lake Texcoco, instead 

 of into its own lake of Xaltocan. The scheme formed by Enriquez 

 de Almanza to remedy this evil was kept in abeyance, as his services 

 were required in Peru. 



In the year 1604 a serious inundation attacked Mexico City. The 

 Marquis de Montes Claros did all in his power to carry out the plan of 

 Senor Don Martin Enriquez to relieve the rivers of the north and of 

 the valley of the excess of water from the central and south lakes, 

 which are of higher altitudes. The pros and cons of this plan were 

 beset with many great difficulties, and respecting one of the methods 



