56 BULLETIN 300, U. S. DEPARTMENT OF AGRICULTURE. 
TABLE 24.—Operating data for United States hydraulic dredges. 
Average 
Diameter | gauge | Average suaraee Coal 
of dis- Weateral pressure | vacuum | Total ee ag a hese As Total 
charge = = in dis- in suc- head. separ yard. excavation. 
pipe. ee tion pipe. ing. pumped 
Pounds 
per square Cubic 
Inches. inch. Inches. Feet. yards. | Pounds. | Cubic yards. 
1A) SS ain de a a ees 14 15 49 89 13.3 163, 288 
12>) Sand and shellss-ses-54-5--42 9 20 43 97 15. 63 9,172 
12 | Sand, gravel, shells. ....-.-- 18 10 53 199 6.5 16, 889 
123 Sands 86 heer eee 18 12 55 107 6.35 55, 131 
12) | Sand and:eravel =22-.-..----. 14 9.7 42 76 14.4 123, 959 
6 ap alo S865 Cree eae 5 Aas 10 14 39 105 12.6 165, 028 
NG Sooo Sets eae ete ae ee | 16 15 54 181 4.22 376, 079 
15 | Mud, clay, sand.........-....| 12.6 16.9 48 141 9.8 230, 257 
15 | Gravel and sand..-....-.-..---| 12 20 50 257 6.79 | 310, 370 
15 | Silt, clay, and sand......-... 22 18 71 172 8. 64 488, 875 
Poe Mirdiandisilts-. see ene 18 12 55 293 3.2 792, 807 
15 | Mud, clay, and sand......... 3.5 il 21 309 ASFA 1, 078, 285 
15 | Sand, mud, and shells. ...... 16 Fi 45 551 3.35! 1,298,597 
18 | Sand-and mud...._.2...2.... 14 18 53 | 113 15°) 1) FSesees 
18 | Sand and mud, some rock... 22 9 61 286 6.7 | 1,045, 689 
20s aSandand ROCKS ee eee 15.4 16 54 336 5.27 365, 433 
20 | Mud, sand, and shell-.-.....- 28 14 80 1-130 4.31 444, 665 
20 | Sand, mud, and stiff clay.... 25 12 71 180 8.41 527, 360 
20 | Mud and clay.-.....-..-....: | 28 18 85 685 2.45 | 636, 417 
20) | SMudrand'sand@-=22- 555-222 5- | 32 12 87 503 7.33 | 1,270; 703 
20 | Mud and clay........-..----- 21 15 65 827 2.48 | 1,341, 835 
203 Silt quicksand Sees se 32 12 87 369 3. 75 1, 687, 476 
207 | SMud sand slay s95 5022 me. e | 8 69 1,016 3.07 | 3,697,875 
24 | Sand and gravel.........._..; § 13.5 36 542 10.4 59, 702 
1 Annual Report, Chief of Engineers, United States Army, Floating Plant (1915). 
USE IN LEVEE CONSTRUCTION. 
The hydraulic dredge can be used successfully in constructing 
levees where water and soil conditions are suitable and where there 
is sufficient yardage to pay for the installation of such a machine. 
Suitable soils are those largely composed of sand with some silt or 
clay. Ifa large amount of silt or clay is present there is a tendency 
for the material to remain in suspension for considerable time and 
it is difficult to form the levee. Plate XIII, Figure 1, illustrates the 
method of forming the desired slopes by means of steel boards. 
These boards, made of No. 14 gauge steel, about 18 inches wide and 
10 feet long, with angle-iron top, are light enough to be easily moved 
by one man. They may be placed in a continuous single line along 
the intersection of the side slope with the natural] slope at the end of 
the fill, or they may be placed in a staggered line along the slope as 
shown. Several men equipped with shovels are necessary to dis- 
tribute the material evenly and to move the slope boards ahead as the 
levee is built up. 7 
A hydraulic dredge (PI. XIII, Fig. 2) with hull 90 by 24 by 54 
feet, having a centrifugal pump with 12-inch suction pipe, 14-inch 
discharge pipe, a 250-horsepower tandem compound engine, and a 
locomotive-type boiler nominally rated at 150 horsepower, was used 
in constructing a section of levee along the Mississippi River near 
BEF Pn. SBE SR i. Se Seas 
