Effects of Forests Upon Run-off in the Rockies 73 



The following factors seem most important and hourly 

 records of them should in any case be obtained though a large 

 outlay of self-registering instruments is required : 



Streamflow 



Precipitation 



Air and soil temperature 



Evaporation 



Humidity 



Wind velocity and direction. 



The run-off from each watershed in cubic feet should be 

 determined for the year and expressed in per cent of the pre- 

 cipitation. Evaporation is a very important factor in water- 

 loss and special precautions should be taken in order that 

 accurate records may be obtained with the conditions of cover 

 in contrast. The time and degree of floods and low water 

 stages as related to precipitation and thaws of known in- 

 tensity should be determined. Lastly, the silt deposited in the 

 basin should be most carefully measured since the effect of 

 forests upon the retardation of erosion is a very important 

 question. With accurate records of the above enumerated 

 factors it seems possible that some conclusion could be drawn 

 which would help to settle the question of the effect of forests 

 upon run-off, erosion, and water supply. 



