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NEW YORK STATE MUSEUM 



in summer and no injurious excess in winter." 1 So far as known 

 this was the earliest river conservancy commission. This com- 

 mission does not appear to have regulated the river very 

 effectively, since many inundations occurred afterwards, and in 

 1495 A. D. an accurate record of overflows was commenced. The 

 flood of 1495 was, with a few exceptions, one of the heaviest 

 known. Since that time serious floods have occurred on the Tiber 

 in 1530, 1557, 1598, 1606, 1637, 1660, 1686, 1702, 1750, 1805, 1843, 

 1846 and 1870. 



The town of Ostia, when founded, in 633 B. C, was at the 

 mouth of the Tiber and soon had 80,000 inhabitants. In the 

 course of years Ostia w r as deprived of its port by the silt carried 

 down by the Tiber. Thereupon the Emperor Claudius, about the 

 beginning of the Christian era, presented to the Roman senate 

 a project for forming a port three miles from the original mouth. 

 A basin, with two moles, a breakwater, towers and a lighthouse, 

 was executed and a canal opened to connect with the river. This 

 canal silted up towards the end of the first century. The Emperor 

 Trajan repaired the port, adding an internal basin. The canal 

 which still forms the navigable mouth of the Tiber was opened 

 about 110 A. D. Plutarch, in his life of Julius Caesar, states that 

 Caesar intended to remedy the evil by deepening the mouth of 

 the Tiber, but that his death prevented the accomplishment of this 

 task. 



An extraordinary inundation of the Tiber is mentioned by the 

 younger Pliny, in his letter to Micrinus, as occurring in the reign 

 of Trajan, who, as already stated, built a canal which still exists. 

 The present length of this canal is about two and one-half miles. 2 



In reference to the reason why the Roman senatorial river 

 conservancy commission did not succeed there is but one remedy 

 which can be applied to a river in order that there may be no 

 deficiency in summer and no injurious excess in winter, namely, 

 water storage. The valley of the Tiber does not present the 

 proper conditions for applying this remedy. In its lower reaches 

 the Tiber flows through a broad plain, while in its upper reaches, 



lThe Tiber and Its Tributaries, by S. A. Smith, 1877, p. 00. 



2W. Shelf ord, on Non-tidal Rivers, Proc. Inst. C. E., Vol. LXXXII, pp. 

 7-8; and The Tiber and Its Delta, by Trof. Ponzi, Troc. Inst. C. E., Vol. 

 XLV1I, pp. 342-344. 



