on the basis of past observations of the author and associates. The totals 

 thus derived are believed conservative. While they cannot be presented as 

 completely accurate determinations, they are believed sufficiently reliable 

 for comparative purposes. 



FARM POND STUDIES 



Selection and Description of Ponds 



All ponds used were typical farm or ranch ponds, most of which were 

 built for stock-watering purposes. Cooperation and interest of the land- 

 owners, as weli as size and other physical characteristics of the ponds 

 were considerations in theit selection. Clear ponds are rare in central 

 Oklahoma, and the use >jf an airplane saved much time. Once a iclear pond 

 was located from the air it was relatively simple to match it with a muddy 

 pond in the same watershed. Ideal situations were those in which two ponds 

 were located in the same drainage, one immediately above the other. Such 

 upper ponds served as settling basins and were almost invariably muddy, 

 while the lower ponds were usually clear. Single ponds without settling 

 basins were seldom clear except when located in well-grassed pastures 

 having an efficient means of runoff control. 



A total of 39 ponds were selected for study. Sixteen were located 

 in Cleveland County, 23 in Payne County, approximately 70 miles north 

 and slightly east of the Cleveland Coxinty area. Land use, soils, and 

 sxibstrates of the areas are very similar, both underlain by Permian red 

 beds, with surface soils containing much colloidal clay. Sizes of ponds 

 used and other physical characteristics are presented in Table 1. 



