HiGGiNSON. — On Floods ill Lake Districts. 18-j 



what will eventually prove more serious, should the destruction of timber 

 not be checked, many of the streams will dry up during the summer 

 months. 



The Commission of Italian engineers which has lately investigated the 

 cause of the recent terrible floods in the Eiver Po, reported that during the 

 present century these floods have been progressively increasing in height ; 

 that the expedient of attempting to confine them within the channel of the 

 river by continual additions to the height of the artificial banks, has been 

 considered inapplicable, as being a method tending to increase the very 

 dangers it is intended to prevent. 



For this reason the object sought by the commission was rather the 

 reduction of the floods themselves, or at all events the arrest of their 

 increase. This involved the investigation of the influence on the volume 

 of the river of the denudation of the growth of wood on its banks ; the 

 suggestion of legislative measures; the construction of storage basuis or 

 lakes to retain the flood- water for subsequent distribution for the purposes of 

 irrigation, together with numerous other matters affecting the river. The 

 result of this examination was that they estimated it was necessary to spend 

 £600,000 in strengthening and restoring the banks, and a further sum of 

 £320,000 for subsidiary works. 



Another Commission also lately appointed to report on works necessary 

 to prevent inundation of the Eiver Tiber in Eome, had the following pro- 

 posed remedies to investigate and report on — 



1. Ee-wooding the banks of the Tiber 



2. Storage lakes or basins of reserve 



3. Total deviation of the course of the Tiber 



4. Partial diversion of the water 



5. Limitation of the flow through the city 



6. Eectification of the channel 



7. Additions to the banks and lateral defences. 



The Commission decided to increase the discharging capabilities of the 

 two channels existing, by widening and clearing the bed within the city and 

 embanking and regulating the course above it. 



These particulars are obtained from the Italian Civil Engineers' Journal, 

 and a writer in the same remarks, with reference to the remedies mentioned 

 in the before-mentioned list, that with regard to the first remedy of re- 

 wooding the banks too little is known of the requisite details, and that the 

 result of any operation of this nature would be too slow in its development 

 for it to be relied on as a prevention of flood ; as to the second proposal of 

 storing storm water in artificial lakes, the only experience cited in modern 

 times is in the basins of the Upper Loire in the south of France, which 

 works were executed in 1711. x 



