DRAINAGE OF WET LANDS OF SOUTHERN LOUISIANA. 



11 



addition to the former ceases, and if conditions are favorable, a new layer of 

 vegetation is formed on the silt above. Thus we have strata of muck varying 

 in thickness from an inch to several feet, with intermediate strata of silt of 

 depths of from 1 inch to perhaps 2 feet. About half of the waterways that 

 extend through these swamps are streams of tidal erosion, and along these 

 streams the high ridges of river silt are absent and the muck is especially deep. 

 Bayou des Allemands, Wax Bayou, and Little Wax Bayou are streams of this 

 character. 



The samples of muck examined were taken at just sufficient depth below the 

 surface to insure the optimum percentage of water — i. e., the amount of moisture 

 considered by local plantation owners to be the best for the growth of general 

 field crops. No samples were taken immediately after a rain nor after a long 

 dry period. At the time of taking the samples a description of each field was 

 made, including depth of water table, length of time the field had been drained 

 and cultivated, time since last rainfall, character of original vegetation, nature 

 of present crop, and other conditions peculiar to the tract in question. 



The following tables show the results of tests made during the spring of 1910 : 



Results of soil tests on area No. 3, Raceland, La. 





Depth 



of 

 sample. 



Num- 

 ber of 

 days 

 since 

 rain. 



Weight per cubic foot. 



Water in soil by volume. 



Depth 

 of 



water 

 table. 



No. of sample. 



Nor- 

 mal. 



Satu- 

 rated. 



Dry. 



Nor- 

 mal. 



Satu- 

 rated. 



Gain. 



Turf: 



12 



Inches. 

 4-10 

 4-10 

 4-10 

 4-10 

 5-10 

 5-10 

 3- 8 

 3- 8 

 6-10 

 6-10 



8-12 

 8-12 

 12-16 

 12-16 

 3- 7 

 3- 7 

 3- 8 

 3- 8 



7 

 7 



10 

 10 

 10 

 10 

 14 

 14 

 14 

 14 



7 

 7 

 7 

 7 

 7 

 7 



10 

 10 



Lbs. 

 45.8 

 54.4 

 44.0 

 45.8 

 43.9 

 46.7 

 41.3 

 41.3 

 51.2 

 47.3 



57.9 

 61.4 

 64.0 

 66.0 

 53.7 

 56.2 

 54.8 

 46.7 



Lbs. 

 61.5 



"*62."3* 



""60.' 7" 

 61.5 



'"hi'.Q 



71.3 



""77." 6* 



'"~67.*9" 



""64."9" 



Lbs. 

 7.0 

 8.7 

 9.4 

 12.4 

 10.7 

 14.0 

 7.6 

 7.9 

 7.9 

 7.3 



21.2 

 22.8 

 29.5 

 30.0 

 14.9 

 16.9 

 16.9 

 8.7 



Per ct. 

 62.1 

 73.1 

 55.4 

 53.4 

 53.1 

 52.3 

 53.0 

 53.4 

 69.4 

 64.0 



58.7 



61.8 



55.2 



57.5 



62.0 



62. 9 ^ 



60.6 



60.8 



Per ct. 



87.2 



Per ct. 

 25.1 



Inches. 

 18 



13 



18 



22 







20 



23.... 



79.8 



26.4 



20 



24 



20 



25 



74.7 

 86.2 



22.4 

 32.3 



20 



30 



20 



31 



20 



32 







22 



33 



80.5 



80.5 



16.5 

 21.4 



22 



Turf with silt: 



10 



20 



11 



20 



14 



77.0 



21.8 



18 



15 



18 



16 1 



84.8 



22.8 



20 



I7i 



20 



26 ! 







24 



27 1 



89.9 



29.1 



24 







Turf and silt after being mixed by two years of cultivation. 



The above samples were taken from the soil on area No. 3, which lies about 5 

 miles from Bayou La Fourche and the same distance from the town of Race- 

 land. This district is a part of the open grass-covered prairie and has been 

 well drained for about three years. Its elevation is perhaps a foot above mean 

 tide level, and the soil probably would be classed as " Galveston clay." The 

 fields from which these samples were taken were in cultivation in 1909 and were 

 planted to corn or sugar cane in the spring of 1910. The original vegetation was 

 a wild prairie grass, locally called " paille fina." It was from this grass that the 

 muck or turf was formed. The soil of the top 4 to 5 inches was quite soft and 

 dry, having been recently cultivated. Just below the depth of cultivation the 

 soil became moist, and when compressed water would drip from it. The muck 

 here was of a dark-brown color and was very light and spongy ; after drying 

 it became much darker in color. It seemed to be a mass of partially decayed 

 grass and grass roots, and had very little, if any, silt in its composition, The 



