STEP VIII 
Using the most likely value of surface water temperature obtained 
in Step VII and the most likely vertical temperature differences at each 
depth for the coldest month (January) and the warmest month (August) 
from Table VII, the following estimates of the most likely temperatures 
(means) at various depths can be made: 
Depth Jan (°F) Aug (°F) Annual Range (°F) 
Surface 62.3 84.1 21.8 
10 feet 62.4 83.7 21.3 
20 feet 62.5 83.2 20.7 
30 feet 62.6 82.2 19.6 
50 feet 62.6 79.9 17.3 
70 feet 62.8 77.1 14.3 
100 feet 62.7 Uo i 9.4 
150 feet 63.3 70.3 7.0 
180 feet 63.5 70.0 6.5 
STEP IX 
An estimate of the temperatures at each depth may be made for the 
intermediate months of the year by assuming that the seasonal 
temperature change at each depth is proportional tothe seasonal change 
at the surface. These estimates can be made by use of the following 
equation: 
R 
aS Gl (Ge up Vi ge 
m 
aml > Ss Fs ee ea (Equation 1) 
8 
where, 
T__.=temperature at depth (d) for month (m) 
md 
R ,=annual range of temperature at depth (d) 
R_=annual range of temperature at surface 
Ting em erature at the surface (s) for month (m) 
T. =temperature at the surface (s) for coldest month (c), (January 
in this example) 
To g=temperature at depth (d) for the coldest month (m) (January) 
Using Equation 1, an estimate of the most likely temperature at 
the 10-foot depth in March is made as follows: 
