SOUTH DAKOTA 
Weather and Water Conditions 
During May, water conditions were characterized by a general 
dryness, with a spotty distribution of water areas. South Dakota 
received very little snow during the winter of 1957-1958; consequently 
no spring run-off occurred to fill the potholes. Very good water area 
densities were found in the northwestern quarter of Stratum No. 2, and 
this apparently was due to heavy local rains which occurred there in 
late April. Over most of the remainder of the State many potholes were 
dry at the end of the May survey period. Lake Preston was dry and cul- 
tivation of the lake bottom had begun. 
By June lst scattered rains began and continued generally over 
the State through mid-July. ‘The greatest rainfall during this period 
occurred west of the Missouri River and in the north-central and north- 
eastern part of the State. Temperatures for the period were well below 
normal. During the last two weeks of July temperatures continued below 
normal precipitation was light. 
As of August 1, South Dakota was 5" below normal rainfall. 
However, cool weather had reduced water losses that would have normally 
“oecurred and the present state-wide water conditions are moderately 
‘good. The most favorable conditions exist west of the Missouri River. 
and in the north-central part of the State. 
Usually the July water area index is lower than that of May. 
This was true in Stratum 2 where a decrease of 15% was observed. In 
the remaining two strata increases were noted of 40% in Stratum 1 and 
of over 200% in Stratum 3 (West River). 
Bre Po tion Indicies 
Although the pond density dropped from the previous year, 
the waterfowl breeding population increased somewhat. ‘The population 
and the water situation is still considerably below the average of 
1950-1956. The species composition as presented in the accompanying 
table was taken entirely from the aerial data. This differs markedly 
from the composition obtained by ground observations during previous 
years, as is to be expected. Since this difference exists, no appli- 
cation should be attempted using this species composition breakdown. 
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