OFFICE OF PUBLIC ROADS AND RURAL ENGINEERING. 377 



The results of two years' study of rates of run-off from drainage 

 districts alono^ the east coast of Florichi have been compiled in a 

 progress report prepared in mimeographed form. 



The run-off studies in Tennessee were continued through the year, 

 and measurements were made to determine friction coefficients in 

 drainage ditches. 



DRAINAGE OF TILLABLE LANDS. 



The laboratory studies of capacities of tile drains being conducted 

 on the Arlington farm, Va., have been nearly completed. Some field 

 studies of this subject on parts of actual drainage systems have been 

 begun. 



Observation wells have been installed in tile-drained fields and in 

 comparable undrained land on farms in North Carolina, South Caro- 

 lina, Georgia, and Arkansas to determine the effects of underdrains 

 upon the elevation of the ground-water table. 



A careful field investigation was made, and Department Bulletin 

 512, " The Prevention of Erosion of Farm Lands by Terracing," was 

 issued to explain the best tj^pes of terraces where terracing ma}^ be 

 practicable. In cooperation with the College of Agriculture, terrace 

 systems were designed as demonstrations for a few farms in Missouri 

 tmd the constniction supervised. 



A report upon " The Drainage of Irrigated Shale Lands " has been 

 published as Department Bulletin 502. 



The investigation in the Yakima Valley, Wash., of the construc- 

 tion of drainage ditches and the effect upon the ground-water eleva- 

 tion has been completed. 



A series of five lectures and five field demonstrations upon tile 

 drainage principles and practice was given at the short course of the 

 Georgia College of Agi^iculture. 



Reports have been prepared and transmitted to landowners, giving 

 detail plans and cost estimates for tile drainage and terrace systems 

 upon just 200 farms. 



OVERFLOWED LANDS. 



The report embodying plans and cost estimates for protecting the 

 bottom lands along the Kootenai River in Idaho has been completed 

 and transmitted to the interested landowners. 



A reconnaissance survey and preliminary report were made upon 

 the drainage of overflowed lands in the Grand River Valley, Mo. 

 Approximately 285,000 acres along the Grand River and its tribu- 

 taries are subject to inundation. 



A survey was made and plans prepared for the protection and 

 drainage of about 38.800 acres subject to overflow along Clear Boggy 

 River in southeast Oklahoma. 



Using topographic and flood data available from other sources, 

 supplemented by our own field investigations, a general plan of flood 

 protection has been prepared for 90,000 acres of land along the Sagi- 

 naw River and tributaries in Michigan. 



Surveys and detail plans for drainage have been made for 7 smaller 

 districts subject to periodical overflow ; preliminary inspections and 

 reports have been made for 17 additional areas where the landowners 

 wished to organize drainage districts. 



