434 



NEW YORK STATE MUSEUM 



New York State exceeded, iu 1902, $3,000,000. If damages of 

 every kind could be reckoned they would amount to at least 

 $1,000,000 in any year. 



Irrigating streams. There is a class of streams which, through 

 the tendency to elevate their beds and widen their channels, noted 

 in a previous section, have actually raised themselves several feet, 

 and in some cases twenty to thirty feet, above the surrounding 

 country, so that whenever there is an overflow from the main chan- 

 nel, the water runs away from the streams, considerably compli- 

 cating the construction of permanent regulation works. But there 

 are, fortunately, only a few such streams in this State and none 

 of those very important. The Missouri, Mississippi, Ked and 

 other rivers may be cited as streams of this character. The writer 

 also remembers the case of the Clear fork of the Brazos river, 

 in Texas, where a railway bridge crossing the stream was set 

 level, with a down grade to the east for one half mile of 20 feet, or 

 the country one-half mile east of the stream was about 20 feet 

 lower than at the stream. There was also a down grade to the 

 west of from 20 to 30 feet per mile, for one and one half miles. 

 The writer's recollection is that two miles west the country was 

 about 30 feet lower than at the stream. 



Insufficient watencay of bridges. One main reason why bridges 

 are so frequently carried away in floods is because of insufificiency 

 of the waterways. Every student of hydrology understands that 

 the catchment above a bridge should be ascertained, and a water- 

 way, large enough to allow for all contingencies, provided. Never- 

 theless, under the system of building bridges by road commission- 

 ers, this is hardly ever done. Economy seems to be the sole 

 consideration. The result is that bridges are carried away, and 

 the writer ventures the opinion that enough money has been spent 

 in the State of New York on renewal of highway bridges alone in 

 the last ten to twenty years to make permanent bridges over every 

 stream in the State. So long as the fact remains as it is, the 

 writer can not but think that the carrying away of such bridges 

 is due rather to the lack of definite knowledge on the part of the 

 road commissioners than to severity of floods. 



Before designing a permanent bridge, the catchment area above 

 the proposed location should be ascertained, together with the 



