18 



THE IRKIGATION AGE. 



DRAIN TILE BULKHEADS. 

 Concrete Retaining Walls Protect Tile Outlets. 



In developing the low lands for farm purposes 

 and such lands are now the most valuable immense 

 sums of money have been spent in tile drainage. Too 

 frequently a valuable tile drain is ruined by leaving 

 the mouth of the tile unprotected. In such case the 

 end tiles wash out: cattle tramp in the ditch; small 



Fig. 1. A Straight Retaining Wall With Crating Inside Tile. 



animals build' their nests up the tile; the outlet fills 

 up, and crops drown out. Such a great loss can be 

 prevented by a small outlay of time and money in 

 building a concrete bulkhead or retaining wall to pro- 

 test the tile outlet. 



The straight retaining wall, shown 

 in Figure 1, is a type which is 

 often built where the open ditch be- 

 gins at the end of the string of tile. 

 However, most tile drains empty through 

 the earthen side bank of the stream. Under 

 these conditions, a better design is a re- 

 taining wall consisting of a head and wing- 

 walls as shown in Figure 2. 



For building retaining walls, choose 

 a dry time of year when there is little or 

 no water in the open branch. Consider, 

 for instance, a tile emptying into a ditch 

 six inches above stream bottom and three 

 and one-half feet below the level of the 

 ditch bank. Plan the bulkhead with a five- 

 foot length of head wall and two wings 

 three and one-half feet long. Slightly back 

 in the bank, dig the foundation trench 

 twelve inches wide and extend it two feet 

 below the bottom of the open ditch. Turn 

 the trench for the wingwalls at such an 

 angle that the ends of the finished wing- 

 walls will project back into the ditch bank 

 and will' be at ground level. 



Old lumber will do for the forms. 

 One-inch siding on two by four-inch up- 

 rights is good. Space the uprights about 

 two and one-half feet apart. Let the back 



walls of the forms stand vertical and incline the 

 front walls towards the bank so that the concrete 

 will decrease in thickness from twelve inches at 

 the bottom to six inches at the top. At the proper 

 height to meet the tile drain, set a first class drain 

 tile (at least one size larger than the regular 

 string) in the forms so that its front end will be 

 Hush with the outside of the wall after the con- 

 crete is placed. Bore four one-inch holes in the front 

 form around the tile and place in them 

 well greased wooden pegs. After the 

 concrete has become hard, the pegs are 

 removed and, by means of cement 

 mortar, bolts are fastened in these holes; 

 supporting a grating for keeping out 

 muskrats. skunks and rabbits. 



Mix the concrete one part Portland 

 cement to two and one-half parts sand to 

 five parts crushed rock or one part cement 

 to five parts bank-run gravel. If the 

 trench should contain a little water, mix 

 so much of the concrete dry as will be 

 required to take up the water. Make the 

 remainder mushy wet. For the front of the 

 wall, work a wooden paddle or a straight 

 spade back and forth between the concrete 

 and the forms so as to force back the peb- 

 bles and to give a neat mortar finish. At 

 intervals of one foot in height, lay old iron 

 rods in the concrete at the junction of the 

 head and wingwalls. Smooth off the top 

 of the wall with a wooden float and finish 

 with a steel trowel. Remove the forms 

 after one week and fill in earth behind the 

 wall to its top. With bolts, attach an iron grating 

 or a screen of woven wire fencing to keep small 

 animals out of the tile. 



For a bulkhead of the dimensions given 



Fig. 2. Wingwalls Prevent Bulkhead From Being W'ashed Out. 



