DRAINAGE INVESTIGATIONS. 41 



in the United States and abroad. Special examinations are made of 

 the soils that are most difficult to reclaim, such as peat and turf lands., 

 tidal marshes, and the heavv alluvial soils, and of the effect of drain- 

 age upon the texture of soil. Investigations are made to determine 

 the value of cement drain tile. Various types of excavating ma- 

 chinery are observed, and their fitness for the different kinds of drain- 

 age construction noted. Pumping plants are examined, and tests of 

 their efficiency under different conditions have been made. 



A large part of the work of drainage investigations is making sur- 

 veys and preparing plans for draining lands permanently wet or 

 periodically iiumdated. These surveys are undertaken in response 

 to requests received from individuals and from organizations for 

 assistance in initiating or perfecting drainage improvements. A 

 preliminary investigation is first made by one of the drainage engi- 

 neers, who ascertains approximately the extent and nature of the 

 survey, the manner of conducting the field work, the probable benefit 

 to property from drainage, as well as the interest shown by tho>e 

 who propose to carry out the project. When it is expedient for the 

 Office to lend further assistance, a surveying party is organized. This 

 party obtains accurate information regarding the existing water- 

 courses, the area to be benefited, the slope and elevations of the 

 ground surface, the proper location of new channels and levees, with 

 any special data that may be helpful in designing the most practi- 

 cable method of improvement. A report and maps are then pre- 

 pared, setting forth the conditions existing, showing the proposed 

 plan of drainage, and giving an estimate of the cost of construction. 

 To determine the proper plan for a district, the field data should be 

 collected with care, and good judgment must be exercised in the use 

 of all information bearing upon the project. It is necessary to study 

 carefully the amount and distribution of rainfall, the readiness with 

 which water percolates through the soil, and the most practical meth- 

 ods of excavating ditches and building levees. All the details are 

 fully considered and so explained that the plans can be followed with 

 confidence. The report and maps, with such profiles and other draw- 

 ings as are required, are transmitted to the local parties interested. 

 Owing to the increasing interest in land drainage, the number of 

 requests for personal examinations and surveys is greater than can 

 be met by the drainage staff, so it is necessary to select with care those 

 projects which are most representative, and in localities where land- 

 owners are most willing to cooperate and to carry out the work that 

 may be found practicable. 



The work is done under the inunediate direction of C. G. P'lliott, 

 chief of drainage investigations of this Office, and may be classi- 

 fied as follows: (1) The improvement of farm lands already under 

 cultivation, which is considered of equal importance with the recla- 



