6o ENGINEERING FOR LAND DRAINAGE. 



within the limits of the allotted time and expense. 

 Every thorough-going engineer takes pride in making 

 his work as complete as possible, even at the expense 

 of using more time and labor than he may be paid for. 



The Preliminary Survey, 



The preliminary survey or reconnoissance consists in 

 making a personal examination of the ground with 

 reference to its general features or geography, using for 

 this purpose any surveys or maps that can be obtained 

 and information that can be gathered from residents 

 and others who may be acquainted with the land. It 

 should include an examination of the water-courses 

 and ditches, where their source is, and where they dis- 

 charge. The kind of soil may often be read from the 

 character of the vegetation. The object of this <* re- 

 viewing '* is to determine the practicability of some pro- 

 posed drainage scheme, or to plan for a more complete 

 survey of the field or tract. If it is simply a field, a 

 few levels may be taken, and the water-shed lines be 

 determined, when the engineer can at once make his 

 plans and proceed with the location work. This is the 

 simplest form of outline survey and is applicable only 

 to fields whose drainage limits and slopes are easily 

 determined or in the case of extended tracts, for the 

 purpose of planning for a more complete survey. 



There are several methods of making a more detailed 

 survey, and the value of each will depend upon the 

 nature of the tract and the object sought by the sur- 

 vey. The following are some of the plans which are 

 adapted to this class of work. 



