74 Proceedings oe Ninth Annual Meeting 



plantation had finished its cultivation of the crops but had not as 

 yet beg-un to harvest, giving a supply of labor for the v^ork v^ith- 

 out interference with the plantation operations. The smaller 

 undergrowth was removed first, piled along the banks and burned 

 when sufficiently dry. The trees, logs and stumps were then re- 

 moved and placed upon the banks in suitable lengths for hauling 

 away for use as firewood. In many instances the roots of the 

 larger trees and old snags could not be removed without an 

 amount of efifort which would have added greatly to the cost of 

 the work. These were sawed off even with the' bank or bed of 

 the bayou and allowed to remain. They might have been re- 

 moved rather cheaply by the use of dynamite had the facilities for 

 that work been available. 



The height of the water. at the dam required to raise the water 

 to a reasonable depth over the section of the bayou to be im- 

 pounded was gained by running^ levels along the banks above the 

 site of the dam. The dam was constructed to give a depth of 

 four feet ten inches at the floor of the spillway. When one 

 recalls that the fall in this section averages only six-tenths of a 

 foot to the mile, it is seen that the level at the dam was carried 

 back over the course of the stream for a considerable distance 

 with only a slight variation in depth. The completed dam, with 

 bridge over the spillway, provides a roadway to the section of 

 the plantation lying on the opposite side of the bayou. The fill 

 and spillway of the dam are shown in figures 5 and 6. After 

 completion of the dam, at the onset of winter rains, the water 

 began backing up over the bed of the bayou. Following this first 

 rise quite an amount of debris was floated to the surface, and, 

 as the height of ,the water level increased, this floating material 

 collected along the margins. This was cleaned out with rakes and 

 burned. 



The only maintenance work, in so far as vegetation is con- 

 cerned, was the clearing of the floatage along the banks following 

 the first rise of water over the bed and cutting back a compara- 

 tively small amount of second growth, mostly willow shoots and 

 grass, Zizaniopsis miliacea, that found their way to the surface 

 of the water the following spring. These shoots were removed 

 by the use of a boat and a curved knife on a long handle. Main- 

 tenance work has been required by reason of the work of craw- 

 fish, Cambarus sp., about the spillway in the dam, and this diffi- 

 culty, as well as the effect of the work of the crawfish on the 

 water level above the dam, and in turn the effect of the change 

 in water level on the marginal vegetation, will be discussed later 

 in the report. 



