EEPORT ON FLOODS OP 1865-1866. 227 



" In the departments of the Loire, the p6rim6tres of which the reboise- 

 merit has been decreed to be of public utility do not as yet embrace more 

 than an extent of 1700 hectares, of which about one-fourth part has been 

 sown or planted. These works are evidently too restricted to be able to 

 exert a reaUy useful action on the neighbouring water-courses, the floods of 

 which are so sudden and so disastrous. But it has been established that 

 they have reduced, in some measure, the rapidity of the flow by the 

 obstacles created, not only by the plants, but also by the dense herbage 

 and bushes which have grown since the grounds were enclosed, or mise 

 en defends. 



" The numerous harraoes erected in the department of Iske have acted 

 well ; they have prevented the crumbling down of the hills, — they have 

 slackened the flow of the waters, and arrested on their way the enormous 

 masses of earth and stone which previously would have precipitated them- 

 selves to the bottom of the basin. As for reboisements, properly so-caUed, 

 they had not been undertaken to any extent previous to 1863. The works 

 are thus of too recent a date to be able to modify the rigime of the waters 

 of the district ; but the enclosures, les mises en difends, which have followed 

 as a matter of course the declaration of the public utility of the reboisements, 

 have had for eff'ect, by covering again vast extents of ground with what 

 may be called a spontaneous vegetation, to arrest the progress of dejections 

 being carried away by the waters. 



" The suppression, or rather the regulation, of the right of way, and the 

 depasturing of these, has produced an almost immediate eff'ect at Valbonnais, 

 and on the eastern flank of the mountain of Connexe. The creation of 

 ravines, previously so frequent, no longer occurs ; and the old ravines have 

 ceased to be a continuous menace to the population, or to the imperial 

 road from Grenoble to Gap, which used to be cut up whenever a great flood 

 occurred. 



"The works of reboisement executed in the Maurienne, department of 

 Savoie, extend only over 500 hectares ; but old drains, transformed into 

 dangerous ravines, have been stopped, and numerous barrages have been 

 established on spots which were formerly more exposed to erosion. These 

 works have stood well, and everywhere they have prevented the disintegra- 

 tion of the soil. 



" The departments of the High Alps, and of the Dr6me, did not suffer 

 from the rains which caused such great disasters in Central France. Con- 

 sequently, all the works undertaken in these regions by the Forest 

 Administration remain uninjured. 



" In the departments of the Lower Alps, and Vancluse', there have fallen 

 only the usual rains, and there has been no general inundation. 



" The trifling damages caused by the waters have been only local and 

 accidental. But there may be collected, from the consequences of two days 

 of rain which fell, a good many observations which tend to establish the 

 efficacy of the works which have been executed. 



" The ravines which furrow the chantier of the reboiserrient of Barrfime 

 form,erly washed on to the imperial road immense quantities of material 

 torn off from the mountain ; now, the slopes are covered with numerous 

 barrages, and there come to the road only small stones mixed with mud, 

 which are easily stopped by the bordering ditch. In the commune of Saint- 

 Andr6, a mass of schistose granite, completely stripped of wood, and in full 

 process of desintegration, has been almost consolidated through the effects 



