. Bulletin of the Department of Agriculture. Agriculture; Agriculture. 18 BULLETIN- 190, U. S. DEPARTMENT OF AGEICULTURE. BULKHEADS. A bulkhead should be constiTicted at the outlet of the underdrainage system to avoid injury from frost and caving of the banks at that point. This may be made of concrete, brick, or timber. Care should be taken that it has a good foundation, in order that it may not be undermined. Figure 11 shows a concrete bulkhead which may be easily and cheaply installed and which will give satisfactory service. A network of wires or small rods of copper or iron should be
. Bulletin of the Department of Agriculture. Agriculture; Agriculture. 18 BULLETIN- 190, U. S. DEPARTMENT OF AGEICULTURE. BULKHEADS. A bulkhead should be constiTicted at the outlet of the underdrainage system to avoid injury from frost and caving of the banks at that point. This may be made of concrete, brick, or timber. Care should be taken that it has a good foundation, in order that it may not be undermined. Figure 11 shows a concrete bulkhead which may be easily and cheaply installed and which will give satisfactory service. A network of wires or small rods of copper or iron should be placed across the outlet to keep out small SOME TYPICAL LEMS AND TREATMENT. PROB- THEIR INTERCEPTION OF LATERAL SEEPAGE. Figure 12 is a map and cross section of a typical case of water- logging due to seepage from higher lands, to which the interception method of drainage should be applied. The damaging water is conducted through a pervious stratum that lies at a moderate depth, and owing to a Fig. 11.—Concrete bulkhead for protection of outlet of tile-drainage change in slopC f rom a ^^^*^®°^' steep to a Hghter grade this water is forced to the surface.^ The drain should be located at the change in slope, as shown, and should be run diagonally across 1 The slopes of the land are indicated by lines drawn across the map, any one of which lines passes thi-ough points of the same elevation, this elevation being that shown on the line. These are called contour lines. The lines shown on the map are at 1-foot vertical intervals, and may be compared with the successive shore lines of a pond of water which is rising or falling 1 foot at a time. It is plain that the degree of slope of the land is indicated by the frequency of the contour Unes, the latter being close together on steep land and spread apart on land of slight Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and app
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