Procedure 

 Lake size determination: 



By class, with lake size guide 

 By area, dot count 



Determination of elevation, type, 

 clarity, shore cover 



Depth determination: 



By plotting without measurement 



By plotting with parallax measurement 



Determination of shallow area: 



By plotting without measurement, 

 including dot count 



By plotting with parallax measure- 

 ment, including dot count 



By use of formula 



Approximate time 

 required per lake 



1 minute 

 ^ hour 



5 minutes 



5 minutes 

 ^ hour 



^ hour 



1^ hours 



h hour or less 



Three possible combinations of procedures, with time approximations for photo interpre- 

 tation, are as follows: 



1. Low-intensity photo inventory (average of 10 minutes per lake). 



a. Inventory all lakes and ponds within each drainage basin unit by lake type, size 

 class, elevation, water clarity, and shore cover. 



b. Use unmeasured estimates of bank slope, the lake size guide, and a table of mini- 

 mum bank slopes to classify all lakes larger than 1 acre as either "probably deep" (more than 

 15 feet deep) or "probably shallow" (less than 15 feet deep). 



2. Medium -intensity photo inventory (average of 45 minutes per lake). 



a. Inventory all lakes and ponds within each drainage basin unit by lake type, size 

 class, elevation, water clarity, and shore cover. 



b. Use a combination of unmeasured and measured estimates of bank slopes, the 

 lake size guide, and the table of minimum bank slopes to classify all lakes larger than 1 acre 

 as either "deep" or "shallow." Lakes having bank slopes that are judged to exceed the mini- 

 mum required by the table need not be checked with parallax measurements and may be classi- 

 fied as "deep." For all other lakes, take parallax measurements of the one or two bank slopes 

 considered most indicative of lake depth. Classify lakes as "deep" if slopes equal or exceed 

 minimum values in table, "shallow" if slopes are less than these table values. 



c. Use parallax measurements and the formula for calculating shallow area of lakes 

 that seem to justify further evaluation because of size, location, or depth. 



17 



