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M.C. Miller etal. 



place, the ponds are shallow enough that their capacity to store heat is 

 small. Therefore, water temperatures would be expected to reflect current 

 weather rather than to integrate weather over several weeks. When this 

 was tested, Pond C water temperatures were found to have a significant 

 direct correlation with air temperatures. Kalff (1965) also found that water 

 temperatures were significantly correlated with solar radiation. 



As expected, shallow ponds were a few degrees warmer than the 

 deeper ones but ponds with about the same depth had similar 

 temperatures. Thus, Ponds B and C differed by only 0.5°C when 68 paired 

 measurements were compared. Because of this similarity, the water 

 temperatures from Pond C (1971, 1973) and Pond B (1972) were averaged 

 to give a daily mean (Figure 3-3). 



The mean daily temperature rose rapidly in June, peaked in the first 

 week in July, and then slowly declined for the remainder of the summer. 

 Aside from this general pattern, there is little consistency from year to 

 year. For example, the mean on a given day may vary by 10° from one year 

 to the next. Overall, 1972 was much warmer than 1971 or 1973; this agrees 

 with the average air temperature data but not with the solar radiation data 

 (Table 3-2). Water temperatures are higher than air temperatures; 

 between 5 July and 6 August 1971 the simultaneous measurements of air 

 and*water averaged 3.7° and 7.1°C, respectively. 



FIGURE 3-4. Pond C daily range of water 

 temperatures, 1971. 



