274 ANNUAL RErORTS OF DEPARTMENT OF AGRICULTURE. 



RIVER AND FLOOD DIVISION. 

 RIVER AND FLOOD SERVICE. 



A now river district coiiiprising the watersiio'd of the San Joaquin 

 Kiver, formerly a portion of the Sacrainenlo (Gal.) district, was 

 created on March 1, 1912, with headquarters at Fresno, Cal. Greater 

 prouiptness and efficiency of service, without any material increase in 

 cost of operation, will result from this division. Owing to a change 

 in the classification of the station at Moorhend, Minn., the river work 

 of that district was transferred to the station at Devils Lake, N. Dak., 

 on April 1, 1912. The change will not involve any increase in 

 expense. 



One cooperative and 28 paid river stations were established during 

 the year and 10 paid stations were discontinued. Three paid rainfall 

 stations were established and 4 discontinued. On June 30, 1912, river 

 and rainfall observations were made at 483 regular Weather Bureau 

 and special stations, of which 16 arc cooperative stations. Rainfall 

 observations were made at 93 special stations, of which 12 are cooper- 

 ative stations. 



No extensions of moment are contemplated during the coming year. 

 A new district center will be opened on July 1, 1912, at Fort Wayne, 

 Ind., with territory comprising the watershed of the Maumee Eiver. 

 As the new district is now a portion of the Columbus (Ohio) district, 

 no additional expense will be involved beyond that necessary for two 

 new special stations. 



The river forecast schemes for the Ohio River and its tributaries 

 were completed during the year and are now in use. Schemes for 

 the interior rivers of the State of Ohio were also completed, and the 

 scheme for the Savannah River is nearing completion. It is proposed 

 to take up the study of the Mississippi soon, with a view to the prep- 

 aration of similar schemes for that river. 



Floods were frequent and w^idesprcnd during the year, the rivers 

 of the Pacific Coast States alone escaping on account of deficient 

 precipitation. March was the month of greatest flood frequency. 

 Nearly every stream east of the Rocky Mountains was in flood at some 

 time durincr the month, except those along the immediate eastern 

 slopes and in the northern and eastern Lake region. The floods were 

 due to an excess of precipitation, ranging from 2 to 4 inches, falling 

 upon saturated soil south of the Ohio River and upon frozen ground 

 to the northward. Some floods were due to ice, but they were con- 

 fined to the northernmost tier of States, and were not of great impor- 

 tance. The greater floods were caused by a remarkable series of 

 storms that moved northeastward from the extreme Southwest over 

 the Ohio Valley to the north Atlantic coast. Storms of this type are 

 invariably accompanied by heavy rains, and when they are separated 

 by intervals of a few days only floods are inevitable. 



The flood in the lower Mississippi River was the greatest in its 

 history. All high-water marks were exceeded from Cairo to the 

 Passes, except in the vicinity of Vicksburg, Miss., where extreme con- 

 ditions were moderated by crevasses in the levees above. The floods 

 began in March, but did not reach their maximum at New Orleans 

 until May 11; at the end of June flood waters were still flowing 

 through the Hymelia Crevasse, 32 miles above New Orleans. Of the 

 30,000 square miles of territory subject to overflow, about 17,600, or 



