THE HYDROLOGY OF ALASKA 



Arvi O. Waananen 



Hydraulic Engineer, U. S. Geological Survey 

 Washington, D. C. 



Introduction 



Water is one of the most valuable and vital natural resources 

 available to man— but water is more than just a resource. It has 

 played a major role in geologic history because rain, running 

 water and waves are the principal agencies in erosion and sedi- 

 mentation; frost, ice and glaciers have made great changes in 

 the earth's surface, and water has a great power for dissolving 

 minerals. 



The development of water resources requires the determina- 

 tion of certain physical conditions such as the head available for 

 power-development, the favorable sizes for dams or diversion 

 works, etc., but appraisal of the water supply, either flowing 

 in the streams or available in the subsurface reservoirs, is often 

 a problem requiring much study, particularly when adequate 

 flow measurements are not available. These studies must in- 

 clude such items as distribution of precipitation; mean, maxi- 

 mum and minimum flows in streams; frequency of flood occur- 

 rence; volume of subsurface storage; evaporation losses, par- 

 ticularly from reservoirs, that may be considered; transpiration 

 losses and probable ground water recharge from precipitation 

 or spreading of surface waters. 



The United States Geological Survey has been active in the 

 investigation of our water resources since 1888 and makes basic 

 studies of the occurrence, availability and quality of both sur- 

 face and ground water. The Survey's activities have included 

 some water investigations in Alaska in the past and further 

 studies are in progress at the present time. 



Resources development today is desirably accomplished fol- 

 lowing extensive scientific study and evaluation of the resources, 



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