Physics 65 



suddenness. The daily peak occurs earher in the small channels than in 

 Esatkuat Creek, a pattern typical of streams. 



The total runoff from the pond site was 5.7 cm in 1972 and 5.9 cm in 

 1973 (Table 3-8). This amounted to a recovery of 83% of the expected 

 runoff in 1972 and 51% in 1973. The expected runoff was calculated from 

 the snowpack measurement (Table 3-6). Much of the water unaccounted 

 for in the runoff goes to fill up the more than 100 ponds in the watershed. 

 This amount of water is called the dead storage in the total reservoir 

 (Dingman 1973). Usually, this must be filled before the runoff can begin. 

 However, in these ponds, the water does not flow in defined channels so 

 the filling and runoff appear to be going on at the same time. The total 

 amount of dead storage in the ponds is directly related to the pond level at 

 freezeup the previous fall. Our measurements confirm this, as the pond 

 levels were higher in late summer 1971 than they were in late summer 

 1972. Thus, there was a greater dead storage in spring 1973 than in 1972, 

 and the recovery was less (51%) in 1973 than in 1972(83%). 



The only other Barrow area studies that attempted a runoff budget 

 were from Esatkuat Creek (Dingman et al. in press). Recoveries were 95% 

 in 1972 and 93% in 1973. This creek, however, has a well developed 

 drainage with a total elevation difference of 5 m. Although other 

 hydrology studies have been made (Brown et al. 1968, Lewellen 1972), 

 they did not begin until after the bulk of the snowmelt had run off. 



After the initial peak of runoff, the streams at Barrow fall to a very 

 low level. Brown et al. (1968) and Lewellen (1972) measured a summer 

 runoff equivalent of 5% of the summer rainfall. There was runoff after 

 every rainfall so presumably runoff began as soon as the soils became 

 saturated again. This was not the case at the pond site because of the dead 

 storage available as soon as the water levels began to fall in mid-June, and 

 no runoff was observed during the three years from 1970 to 1972. 

 However, in 1973, when the summer rainfall was double the average, the 

 ponds refilled on 17 August and after that date, 86% of the rainfall during 

 the next 7 days passed out through the five small weirs. 



TA BLE 3-8 Water Budget for Pond Site D uring R unoff, 10 to 

 27 June 1972 and 1973 



