
seeds become available for use when there are sporadic winter refloods or 
when the water is high in the spring of the year, and at such times, they 
furnish a valuable supplemental food source. Crop plants for waterfowl 
have not always been sufficient to hold ducks in the lower TVA reservoirs. 
Prolonged flooding of marginal marsh growths in the upper reaches of the 
reservoirs has attracted large numbers of waterfowl additional to mallards, 
blacks, and geese. 
Intensive studies on the management of impoundment margins were made 
in cooperation with Tom Z. Atkeson, biologist of the Wheeler Refuge, and 
Edwin Green, formerly CCC biologist, in 1940-1. Later they were continued 
independently by the writer. This program included over 150 plot studies 
on the propagation of waterfowl food and cover plants. Results of these 
investigations reveal that the squarestem spikerush can be planted with 
good results in the back-water areas. This brittle, naked-culm species 
will not withstand extensive wave action particularly when there are changing 
water levels. Propagation of the softstem bulrush (Scirpus validus) should 
be limited to areas where the fluctuation of water is not too severe, as 
in the Guntersville Reservoir. Southern bulrush (Scirpus californicus) can 
be introduced successfully and withstands wave action but it does not readily 
spread its zone of growth. Plants of the common three-square bulrush (Scirpus 
americanus) succeed along exposed sandy shorelines where wave action is too 
severe for other vegetation. 
Propagating these perennial spikerushes and bulrushes has necessitated 
planting their rootstocks -- a laborious job and one which requires care 
for effective results. Long handled shovels have been found efficient for 
planting or "dibbling in" clumps of rootstocks. The latter should be planted 
shortly after being collected and spaced at intervals of one to three feet, 
Results of such plantings rarely show up well until the following season. 
In the TVA impoundments, it was necessary to plant rootstocks at a 
period when the water was drawn down sufficiently to allow successful 
establishment of initial growth and permit survival after further lowering 
of the water. Suitable water levels for planting occur in late June or 
early July when the water has been drawn down a foot to eighteen inches. 
In reservoirs having weekly cyclical fluctuation combined with draw-down, 
plantings were most successful during the low period of the cycle when 
areas selected for planting became exposed. in sandy locations subject 
to wave action, best results with bulrushes were obtained immediately fol- 
lowing emergence of the planting zone at the top of the cyclical fluctuation. 
This allowed rootstocks sufficient moisture to become established and 
prevented them from either being washed out or buried too deeply. After 
plants became well-established they were better able to withstand adverse 
conditions. 
The disturbing of dominant vegetation on the margins, mainly purpletop 
grass, rosemallow, cattail, and woody growths, by bush and bog disking, 
plowing, or other means is sometimes advantageous in locations having slight 
grade. It opens the way for rapid growing pioneer plants valuable to water- 
fowl. Prominent among these are wild millet and annual smartweeds (mainly 
11 
