FLOODS OF THE AED^ICHE. 251 



tended with greater immediate danger to life and property than 

 those of rivers of less rapid flow, because their currents are more 

 impetuous, and they rise more suddenly and with less previous 

 warning. At the same time, their ravages are confined within 

 narrower limits, the waters retire sooner to their accustomed chan- 

 nel, and the danger is more quickly over, than in the case of in- 

 undations of larger rivers. The Ard(^che drains a basin of 600,- 

 238 acres, or a little less than nine hundred and thirty-eight 

 square miles. Its remotest source is about seventy-five miles, in 

 a straight line, from its junction with the Rhone, and springs at 

 an elevation of four thousand feet above that point. At the low- 

 est stage of the river, the bed of the Chassezac, its largest and 

 longest tributary, is in many places completely dry on the sur- 

 face — the water being sufficient only to supply the subterranean 

 channels of infiltration — and the Ard5che itseK is almost every- 

 where fordable, even below the mouth of the Chassezac. But in 

 floods, the river has sometimes risen more, than sixty feet at the 

 Pont d'Arc, a natural arch of two hundred feet chord which 

 spans the stream below its junction with aU its important afflu- 

 ents. At the height of the inundation of 185Y, the quantity of 

 water passing this point — after deducting thirty per cent, for ma- 

 terial transported with the current and for irregularity of flow — 

 was estimated at 8,845 cubic yards to the second, and between 

 twelve o'clock at noon on the 10th of September of that year 

 and ten o'clock the next morning, the water discharged through 

 the passage in question amounted to more than 450,000,000 cubic 

 yards. This quantity, distributed equally through the basin of 

 the river, would cover its entire area to a depth of more than five 

 inches. 



The Ard^che rises so suddenly that, in the inundation of 1846, 

 the women who were washing in the bed of the river had not 

 time to save their linen, and barely escaped with their lives, 

 though they instantly fled upon hearing the roar of the approach- 

 ing flood. Its waters and those of its affluents fall almost as 

 rapidly, for in less than twenty-four hours after the rain has 

 ceased in the Cevennes, where it rises, the Ard5che returns within 

 its ordinaiy channel, even at its junction with the Rhone. In 

 the flood of 1Y72, the water at La Beaume de Ruoms, on the 

 Beaume, a tributary of the Ardeche, rose thirty-five feet above 



