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IMPOUNDING WATER TO CONTROL BREEDING OF MOSQUITOES. 19 
of a variable water level on marginal vegetation and marginal breed- 
ing. This is obtained by a change in the water level from time to 
time. This can be accomplished by a sluiceway through the fill below 
the level of the floor of the spillway. The flow of water through the 
sluiceway can be controlled by a gate. If the sluiceway is placed at 
the level of the bed of the bayou, in the center of the fill, it will act 
efficiently in lowering or raising the water level above the dam, and, 
also, the current of water through the sluiceway at this point will 
flush out and carry away the mud and sediment that tend to accumu- 
late in the bed immediately back of the fill. 
ADVANTAGES OF IMPOUNDING, APART FROM PREVENTION OF 
ANOPHELES BREEDING. 
A special advantage to the plantation, apart from the control of 
Anopheles breeding in the bayou, is the fact that the impounded 
water gives an ample supply of good water for the live stock through- 
out the dry summer season. The land lying between the roadway 
and the bed of the bayou.is ordinarily used for pasture purposes by 
the tenants living along the stream. Except in some instances where 
clearing has been done in a comparatively wide strip of land found 
between the road and the channel of the bayou, the pasture along the 
stream is limited in extent and the grasses are crowded out by weeds, 
bushes, trees, and vines. During the seasons of dry weather the 
water in the natural bayou is shallow and stagnant. The supply is 
often difficult of access by reason of the tangle of overhanging and 
aquatic vegetation. The animals often become bogged in seeking 
the water, and the more shallow and isolated pools are converted 
into wallows, particularly where hogs are pastured along the bayou 
side. The situation under these conditions is unsightly and insani- 
tary and the supply of water is limited in amount and of the 
poorest quality. With the limited pasturage the animals do not 
thrive, and often die. The pasture for the plantation stock—that not 
owned by the tenants—is the wet land lying between the cultivated 
areas and the timber and swamp. These pasture lands extend into 
the timber and the live stock depend upon the swamps and the shal- 
low lakes in the basins of same for water. In any prolonged dry 
season this supply becomes greatly restricted and as objectionable 
in quality as that in the bayou. When this situation becomes acute 
it is necessary for the plantation to drive wells throughout the 
pasture areas and pump water. This adds greatly to the expense of 
taking care of the stock. On Hecla plantation, following the clear- 
ing of the section in Bayou Walnut and impounding the water, the 
_ management not only extended the fencing to include the entire im- 
pounded area, but also arranged the fencing of the pastures in one 
section of the plantation so that by a system of gates the live stock 
