DRAINAGE OF WET LANDS OF SOUTHERN LOUISIANA. 3 



The area of the district is roughly 12,000 square miles, of which amount about 

 10 per cent is high enough to be drained by gravity, this representing the per- 

 centage of the total area that is already drained and under cultivation. The 

 remainder is so low that artificial means must be used to get an outlet for 

 drainage water. The area shown in figure 1 is about one-fourth that of the 

 entire State, yet the tract contains nearly two-thirds of the State's swamp land. 



Throughout the entire district are connecting lakes and bayous, many of 

 which are navigable with boats of considerable draft and beam. The total 

 length of such navigable streams is, roughly, 1,600 miles. The main waterway 

 is the Mississippi River. The Atchafalaya River has lately been opened to deep- 

 water navigation through a dredged channel at its mouth, and vessels of a draft 

 of not more than 20 feet can safely enter it. This system of waterways insures 

 excellent water transportation to the entire district, in addition to the facilities 

 afforded by the railroads, a number of which traverse the district. 



Besides the cities of New Orleans and Baton Rouge, there are several con- 

 siderable towns in the district, including Morgan City, with a population of 

 about 5,000 ; Houma, 5,000 ; Donaldsonville, 4,000 ; New Iberia, 7,500 ; Lafayette, 

 6,400; and Crowley, 5,000. Lake Charles, the principal railroad center of the 

 western part of the State, has a population of 12,000. 



The very small percentage of this area that is under cultivation is worked 

 very intensively and supports a population of over 200 to the square mile. 

 While the principal industry of the whole region is agriculture, the wealth de- 

 rived from other sources, including sea food, lumber, oil, gas, salt, and sulphur, 

 is almost as great. 



CLIMATE. 



Temperature. 



The United States Weather Bureau has issued summaries of the climatologi- 

 cal data of the United States by sections. Southern Louisiana is designated 

 as section 45, and from the summary for this section * the following is taken : 



Climatic conditions over southern Louisiana are marine in character; the 

 proximity of the Gulf of Mexico and the numerous streams and lakes of this 

 region all conspire to modify the temperature conditions and prevent sudden 

 changes therein, and extremely warm weather in summer and severe cold in 

 winter seldom occur. Southerly winds from the Gulf temper the climate and 

 prevent, both in winter and summer, extremes that might otherwise occur. 

 The annual mean temperature is 67.9° F. January is the coldest month, with 

 a mean temperature of 52.4°, while July and August are both warm, with mean 

 temperatures of 81.6° and 81.7°, respectively. The highest annual mean tem- 

 perature is 70.1° at Burrwood, at the mouth of the Mississippi River, and the 

 lowest 66.4° at Cheneyville. The highest monthly mean temperature is 83° 

 at Lawrence in August, and the lowest 49.6° at Cheneyville in January. The 

 range in the annual mean temperature is very slight, and within 100 miles of 

 the- coast amounts to only 1°. After passing inland the change is more abrupt, 

 and over the second hundred miles the gradients are steeper than over any 

 other portion of the State, where the fall in the annual mean temperature 

 amounts to 2° in about 100 miles. The stations with the same mean tempera- 

 ture in July and August are situated in the piney woods and the prairie section. 

 The coast marsh and the alluvial region have the highest mean temperature in 

 July. The greatest difference between the July and the August mean tempera- 

 ture amounts to but 0.7°. January averages about 1° to 2° colder than De- 

 cember and February. The range in the mean temperature between the hottest 

 and coldest months is 29.3°. 



There is a narrow strip along the coast where the temperature has probably 

 never reached 100°, and even as far north as New Orleans it has not reached 

 this degree except in two years, 1901 and 1909. The highest temperature re- 

 corded in the section is 108° at Creneyville, Rapides Parish. The extreme 



1 U. S. Dept. Agr., Weather Bureau Bui. W, sec. 45. 



