DRAINAGE OF WET LANDS OF SOUTHERN LOUISIANA. 5 



Rainfall. 



In regard to the yearly rainfall the Weather Bureau summary of the climato- 

 logical data for section 45 says: 



There is a gradual and well-defined decrease in precipitation from the east- 

 ern toward the western portion of this section. The average annual precipita- 

 tion is 55.76 inches, and ranges from 48.36 inches at Lakeside, Cameron Parish, 

 to 63.02 inches at Amite, Tangipahoa Parish. The precipitation is practically 

 all in the form of rain and is well distributed throughout the year. Snow 

 occurs on an average of once in three to five years, and disappears soon after 

 having fallen. Although droughts occur, they are seldom long continued, and 

 are not so serious as in regions where the level of the ground water is so much 

 farther below the surface of the earth. June and July are usually the wettest, 

 and October and November the driest months. 



Rain falls about once in three days. The average number of rainy days is 

 108 in the eastern and from 77 to 80 in the western portion of this section. 



The following rainfall data are taken from the Weather Bureau records : 



Monthly and annual mean rainfall, in inches, at Cameron, New Orleans, and 



Houma, La. 



Station. 



Jan. 



Feb. 



Mar. 



Apr. 



May. 



June. 



July. 



Aug. 



Sept. 



Oct. 



Nov. 



Dec. 



Annual. 



Cameron 



New Orleans 



Houma 



3.67 

 4.54 

 3.45 



3.34 



4.28 



4.78 



3.39 

 4.56 

 3.52 



3.61 



4.53 

 4.29 



3.61 

 4.06 

 3.59 



5.60 

 5.39 

 5.98 



7.57 

 6.53 

 8.92 



4.04 

 5.65 

 6.43 



5.44 

 4.49 

 5.92 



2.88 

 3.25 

 3.00 



4.12 

 3.81 

 2.73 



3.28 

 4.54 

 4.31 



50.55 

 55.63 

 56.92 



The rainfall in this section is more or less tropical in character, especially 

 during the summer months. The rains are nearly always purely local during 

 the summer, and the amount, both daily and monthly, may vary greatly for sta- 

 tions separated by only a few miles. Thus we have a monthly total in August, 

 1911, of 28.5 inches at Donald son ville, at the northern edge of this section, and 

 but 12.27 inches at Houma, only about 40 miles away. 



The United States Weather Bureau records at the New Orleans station show 

 that there have been 43 storms in the past 22 years, during which the precipita- 

 tion in 24 hours exceeded 3 inches. These storms are classified as to their 

 intensity as follows : 



43 rains exceeding 3 inches in 24 hours. 



19 rains exceeding 4 inches in 24 hours. 



7 rains exceeding 5 inches in 24 hours. 



3 rains exceeding 6 inches in 24 hours. 



2 rains exceeding 7 inches in 24 hours. 



2 rains exceeding 8 inches in 24 hours. 



rains exceeding 9 inches in 24 hours. 



Health Conditions. 

 As regards the healthfulness of this climate the Bureau of Soils says : * 



A most serious check to the attraction of a desirable class of immigrants to 

 this section is the impression which has gotten abroad as to its unhealthfulness. 

 That this idea had some foundation in the past can not be denied, but such a 

 condemnation can not now be applied to the State as a whole or to this par- 

 ticular vicinity. The records of the medical board of New Orleans show that 

 the city has an excellent health record for a city of its size. * * * Outside 

 of the city sanitary conditions are naturally much better. The dwellings of 

 both the owners and the tenants of the plantations stand on the higher land 

 along the Mississippi River, where there is adequate natural drainage. Not- 



1 U. S. Dept. Agr., Field Operations of the Bureau of Soils, 1903, pp. 443, 444. 



