Water Supply Problems in Alaska— Alter 235 



Pumps, control equipment, disinfection equipment, meters, 

 fire hydrants, etc. must all be constructed in a manner which 

 provides maximum protection from low temperatures. 



Extended periods of daylight may play some part in the algae 

 content of waters in the low temperature regions. Figure 9 

 shows approximate hours of daylight that may be expected in 



Table 2.— Air temperature and frost penetration at Alaska stations 



Approxi- Reported 



No. Days Max. mate Depth of Frost 



Annual Temp. 32°F. Annual Penetration 



Station Temp. °F. or Less Degree Days f in feet 



Anchorage 34.7 125 1 1,000 8 



Barrow 9.9 280 20,000 * 



Bethel 29.9 140 13,000 — 



Cordova 40.6 60 10,000 — 



Dillingham 34.3 — — 4 



Fairbanks 26.0 160 14,000 10 



Ft. Yukon 19.7 — — — 



Galena 25.0 180 14,000 10 



Gambell 23.4 205 15,000 — 



Juneau 42.1 55 8,000 5 



Kotzebue 20.7 205 16,000 



McGrath 25.4 165 15,000 7 



Nome 25.7 185 15,000 



Northway 23.0 165 16,000 



Umiat 9.8 240 20,000 



# 



# 



Seasonal frost extends down to permafrost. 

 •j- For any one day, when the mean temperature is less than 65°F., there exists 

 as many degree days as there are Fahrenheit degrees difference in temperature 

 between the mean temperature for the day and 65 °F. 



different northern latitudes. Some algae are found in very cold 

 waters and even in snow. Smith in his work on Fresh Water 

 Algae of the United States reports that temperature is not 

 generally a determining factor in the nature of algal flora. 

 However, very little work has been reported on the algal flora 

 of Arctic water supplies. Specific investigation should be made 

 to determine the need for and methods necessary for providing 

 algae-free and palatable water supplies in the Arctic. 



