8 BULLETIN 304, U. S. DEPARTMENT OP AGRICULTURE. 



the United States has led, to an earlier activity in drainage reclama- 

 tion than has existed in most other portions of our country. The 

 results of adequate protection and drainage are shown by figure 1 of 

 Plate IV, a view of part of a tract of reclaimed land on the Illinois 

 River. 



SIZE OF PUMPING DISTRICTS. 



In order that the building of a levee around a tract of overflowed 

 land and the installation and operation of a pumping plant may be 

 carried out economically at a moderate cost per acre of land re- 

 claimed, it is necessary to have a considerable area included in a 

 single project. Hence, ordinarily the land does not belong to a 

 single owner, but rather to a number of individuals. In order that 

 all the interested landowners may work harmoniously together it is 

 necessary, first, that an incorporated drainage district be formed 

 according to the method provided by the specific laws of the par- 

 ticular State relating to this subject. The officers of the district so 

 formed may then proceed to carry out the successive steps necessary 

 in the inauguration of the construction work. 



Pumping districts of as small an area as 3,000 acres may profitably 

 be formed in favorable locations; but, in general, the expense per 

 acre is less as the district is larger up to a certain limit beyond which 

 there is no further advantage from increased size. According to 

 experience, about 10,000 acres of reclaimed land seems to be a very 

 satisfactory size for such a district. 



However, the boundaries of a district are determined largely by 

 the natural surface conditions. A district will naturally include all 

 the land on one side of the river between the channel and the bluff 

 and extending up and down the valley from one tributary to the 

 next of any size entering the river On the same side. The tendency 

 in recent years has been to make the districts larger and to extend 

 them beyond the so-called natural boundaries — the tributaries to the 

 river — by diverting these streams around the district or by carrying 

 them by means of levees through the district to the river. The 

 internal drainage channels are carried under these diversion channels 

 by means of concrete inverted siphons or culverts. By this increase 

 in area of the lands organized in one district the expenses per acre of 

 organization and administration during construction and operation 

 are materially reduced. The charge per acre for operation of pump- 

 ing plant is, in general, much less on the larger district. As the 

 valley ordinarily has the same slope as the high-water line of the 

 adjoining river, the lift of the pumps in forcing the drainage water 

 into the river is very rarely increased by extending the district a 

 greater distance along it. On the other hand, smaller districts are 

 being now reclaimed than formerly was the practice. This is due to 

 the increased demand for land, which makes reclamation profitable 



