IMPOUNDING WATER TO CONTROL BREEDING OF MOSQUITOES. 5 
point of origin of the bayou to its junction with Roundaway, the dis- 
tance in an air line is only 74 miles. The bayou, however, travels a 
distance of over 31 miles. The section of Bayou Walnut in its course 
through Hecla plantation is shown in Figure 1. The average fall of 
the bayou in this section is 0.6 foot to the mile. 
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WALNUT BAYOU, (I0UN0, LP. 
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Fig. 1.—Map of section of Bayou Walnut near Mound, La., showing impounded area 
and surroundings. 
During 1914 it was observed that under natural conditions there 
was practically no breeding of Anopheles in certain restricted sec- 
tions of the bayou where open water occurred, where the bed was 
free of vegetation, and where the margins were clean. On the other 
