20 
on 
ro) 
PRECIPITATION, INCHES 
2 
o 
= 
= 
e 
a 
oO 
Ww 
rc 
a 
RUNOFF (INCHES / SQ. MILE) 
Y 
Y 
j 
Z 
MAY JUNE JULY AUG. SEPT. OcT. 
SOOODSSIS}{S§A{SS$$ 66 gq0qgg 
Fig. 9--Mean Monthly Precipitation and 
Runoff, Maybeso Creek. 
19:49'—I953 
Evaporation and transpiration rates decrease considerably in October 
and stream runoff swings sharply upward. Precipitation is heavy 
during this month--generally the wettest month in Southeast Alaska (7)-- 
and quite rapidly satisfies any soil moisture deficit which might have 
resulted from evaporation and transpiration. Stream discharge gen- 
erally continues to increase through the months of November, and a 
portion of December, until cold weather and snowfall result in 
storage of precipitation in the form of snow. Rains are quite common 
during this season when the watersheds may be frozen and snow-covered, 
and associated runoff is rapid. 
Records show that snow first begins to melt on the Maybeso Creek 
drainage some time in April or early May. It swells stream discharge 
until some time in July. Fig. 9 shows that the magnitude of stream 
runoff during the months of May and June is considerably out of pro- 
portion to precipitation intensities received during these months. A 
considerable quantity of this total runoff comes from snow melt. 
Se163.0 
