■ Watersheds 

 A and B 



THE 



WATERSHED 

 STORY 



Among the officially designated studies, 

 "Protection, Grazing vs. Erosion" was the 

 longest continued and is best known today. 

 This project was designed to determine, with 

 considerable exactness, the relation of grazing 

 and vegetal cover to erosion. It has been de- 

 scribed and discussed extensively in the litera- 

 ture of watershed research as the studies of 

 Watersheds A and B, 3 which were first called 

 "Erosion Areas." 



The two Erosion Areas were established in 

 1912. Area A covers 11 acres and Area B 

 covers nine. The two watersheds are about 

 900 feet apart and are at an elevation of 

 10,000 feet on a generally west-facing slope at 

 the crest of the Wasatch Plateau. They are 

 typical small watersheds in the Subalpine 

 zone and were strategically established in an 

 area where thousands of sheep had been 

 trailed summer after summer, where oldtimers 

 and valley residents averred that you could 

 count the number of sheep bands on the 

 mountaintop by the number of clouds of roll- 

 ing dust on the horizon. Each is a complete 

 watershed but neither one has a permanent 

 stream. Soils on both Areas are residual clays 

 and clay loams derived from limestone and 

 shales. Average slope gradient of Area A is 

 18.5 percent; Area B's slope is 16.3 percent. 



Annual precipitation averages 33 inches, 

 but only about 4 to 6 inches come during the 

 3-month summer growing season; and this 

 amount varies considerably from year to year. 

 During most of the year, storms in this area 

 are of low intensity; but in July and August 

 they have a dramatically different pattern. 

 They are brief, narrowly localized, and in- 

 tense. Rainfall at the rate of 2.2 inches per 

 hour for 20-minute periods has been recorded 

 many times on both these watersheds, and 

 such storms hit any given area on the Plateau 

 at least once every few years. 



Several things make these watersheds and 

 their story outstanding. One is the length of 

 continuous observation and study they have 

 had. Another is the length of continuous cli- 



3 Details of description of these two Watersheds 

 and their treatments are from Meeuwig (1960). 



9 



