160 A NEW METHOD OF ESTIMATING STREAM-FLOW 
column (2) when negative by 0.453, and when positive, by 8.39, rounded off to the 
nearest even unit In column (4) is written the value of the constant, C, of 
equation (64). In column (5) are written the sums of the values in columns (3) 
and (4), or the total net melting for the day as computed from equation (64), 
on the assumption that there is an abundant amount of snow and ice available 
for melting. The net melting was computed in this manner from the begin- 
ning of the freezing-melting period the preceding fall, hence many of the late 
r's in June 1913 in the example of observation equations already given, were made 
up in part by the net melting here referred to. In column (6) beginning April 1 1 is 
written the reduced net melting computed from equation (67), as follows: From 
the definitions of A and A x given after equation (67) it is evident that on April 10, 
A— A 
the value of ■ is unity. Hence the reduced net melting for April 11 is the 
A 
same as the net melting. At the end of April 11, A i = 14, in the same units as A and 
as given by equation (64). Hence, A— Ay. = 459 — 14 = 445, making (A— Ai)/A 
= 0.969, which, multiplied into the net melting for April 12, 48, gives the reduced 
net melting, 47, for April 12. This added to the reduced net melting of April 11, 14, 
gives ^i = 61 for April 12, and so on. The computation is carried forward in this 
manner until the reduced net melting is for the last time in excess of 0.005 inch, or 
unity, in the units used. This is taken as the end of the period of reduced net 
melting, or the end of the freezing-melting period. It is to be noted that the 
reduced net melting may go below 0.005 inch several times before it finally goes and 
remains below that amount. The last date on which melting added anything to 
the ground-water storage, according to the computation, was May 9, 1913. On 
May 5, according to the snow-gage record there was a mean water equivalent of 
0.02 inch of snow on the ground, and other observed evidence showed that the 
melting probably became zero on May 9. 
The full net melting and the reduced net melting of Table 42 are shown plotted 
in the upper left-hand corner of Plate 22. 
EXAMPLE OF COMPUTATION OF ^-, STREAM B 
This example will be taken from the computations on Stream B. The values 
of C, F, M and T" used were those shown in Table 49, page 192, as having been 
derived in Solution X. The daily values of all the quantities involved were com- 
puted (or observed), and these daily values combined into monthly totals. The 
E, 
total of all the values in 1911-12-13 was used in deriving — 
E„ 
The unit used (page 161) is 0.01 inch. Substituting the totals in equation 
(35a), page 137, there is obtained 
E t 3900+5646- 1889 _ 
E„~ 2914 
Note that precipitation in the form of rain ordinarily fell in the months May 
to October, and in the frozen form from October to May. In seven of the 36 months 
