12 FOREST INFLUENCES. 



nieiit, meaning thereby not only the use of water for irrigation in the arid and sub- 

 arid regions, but the rational distribution and use in the humid regions of available 

 water supplies by means of -horizontal ditches and irrigation systems, combined 

 with proper mechanical jireparation of the soil, and with drainage systems, with 

 the object of fully utilizing the water for plant production and providing for the 

 safe and harmless removal of the surplus. 



The i>resent policy of forest production and of allowing our waters to run to 

 waste not only entails the loss of their beneficial influence upon plant production, 

 but permits them to injure crops, to wash the fertile mold from the soil, and even to 

 erase and carry away the soil itself. 



It is upon these considerations that the association respectfully suggests to the 

 honorable Secretary the desirability of utilizing the Weather Bureau, the various 

 agricultural experiment stations, and other forces, in forming a systematic service 

 of water statistics, aud in making a careful survey of the condition of water supplies, 

 which may serve as a basis for the application of rational principles of water man- 

 agement. 



How poorly we understand the use of these supplies is evidenced 

 yearly by destructive freshets and floods, with the accompanying wash- 

 ing- of soil, followed by droughts, low water, and deterioration of agri- 

 cultural lands. 



It may be thought heterodox, but it is nevertheless true that the 

 manner in which most of the water of the atmosphere becomes avail- 

 able for human use (namely, in the form of rain) is by no means the 

 most satisfactory, not only on account of its irregularity in time aud 

 quantity, but also on account of its detrimental mechanical action in 

 falling; for in its fall it compacts the ground, impeding percolation. 

 A large amount of what would be carried off by underground drainage 

 is thus changed into surface-drainage waters. At the same time by 

 this compacting of the soil capillary action is increased and evaporation 

 thereby accelerated. These surface waters also loosen rocks and soil, 

 carrying these in their descent into the river courses and valleys, thus 

 increasing dangers of high floods and destroying favorable cultural 

 conditions. 



Here it is that water management and, in connection with it or as a 

 part of it, forest management should be studied; for without forest 

 management no rational water management is -possible. The forest floor 

 reduces or prevents the injurious mechanical action of the rain and 

 acts as a regulator of water flow. Hitherto water management in rainy 

 districts has mainly concerned itself with getting rid of the water as 

 fast as possible, instead of making it do service during its temporary 

 availability by means of proper soil management, horizontal ditches 

 and reservoirs — drainage and irrigation systems combined. It seems 

 to have been entirely overlooked that irrigation, which has been con- 

 sidered only fen- arid and subarid regions, is to be applied for plant pro- 

 duction in well- watered regions with equal benefit and profit, if combined 

 with proper drainage systems and forest management. A discussion 

 of the manner in which the forest influences the disposal of water sup- 

 plies has been made a special part of this publication. 



