Periodic inundations (flooding) of their island city plagued the Aztecs even though the dikes of Nezahualcoyotl and Ahuizotl were built east of the city to stem the tides of Lake Texcoco. The situation continued even after the Spaniards rebuilt the city one to two meters above the Aztec level. The year 1629 is known as the year of the grand inundation with considerable loss of life and property.
Almost annual floods continued for hundreds of years without a solution to the problem. In the year 1862 the Comision del Valle in a bit of a quandary ordered lake levels to be recorded and some enterprising engineer designed the Hipsographic Monument so that levels of the various lakes could be viewed by all. Although finely crafted in marble the monument became a bit of an absurdity in that it did nothing to solve the problem.
Eventually engineering technology caught up with the problem such that a 47km canal with a 10km tunnel was constructed between 1886 and 1900 to drain the valley north to the River Tula. It is interesting to contemplate that right up until the 20th century Mexico was still an island city with the exception perhaps of the swampy west.
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