Table 2. --Daily 10 a.m. water elevations in Snake Island fishway, Potomac River, and provisional mean river 

 discharge in c.f.s. (cubic feet per second) at gaging station 1 mile upstream from Little Falls, 1961 



[Elevation measurements made to nearest 0.5 inch and converted to feet and hundredths of a foot] 



Tall- 

 water 1/ 



Attrac- 

 tion 

 water 



Fish 

 exit 



Head- 

 water 2/ 



Mean drop 



between 



pools_3/ 



Mean daily 

 river 

 discharge 4/ 



May 



6.33 

 6.21 

 6.12 

 5.92 

 5.79 

 5.88 



6.50 

 6.50 

 6.58 

 6.75 



8.00 



7.00 



6.42 

 6.08 

 5.83 

 5.75 

 5.54 

 5.38 

 5.25 

 5.08 

 5.04 

 4.92 

 4.83 

 4.75 

 4.71 



5.88 



4.58 

 4.50 

 4.42 

 4.42 

 4.42 

 4.79 

 4.75 



4.54 



6.25 

 6.08 

 6.04 

 5.75 

 5.67 

 5.79 



6.42 

 6.42 

 6.58 

 6.71 



7.92 



7.00 



6.29 

 6.12 

 5.75 

 5.75 

 5.58 

 5.38 

 5.25 

 5.08 

 5.08 

 4.88 

 4.83 

 4.79 

 4.75 



5.83 



4.71 

 4.62 

 4.54 

 4.50 

 4.50 

 5.00 

 4.96 



4.71 



6.58 

 6.67 

 6.54 

 6.25 

 6.25 

 6.33 



7.17 

 7.08 

 7.08 

 6.75 

 6.75 

 6.83 



7.75 

 7.75 

 7.63 

 7.42 

 7.42 

 7.50 



8.42 

 8.42 

 8.25 

 8.17 

 8.00 

 8.17 



9.08 

 9.17 

 9.08 

 8.92 

 8.62 

 9.08 



9.83 

 9.83 

 9.75 

 9.58 

 9.33 

 9.58 



10.58 

 10.58 

 10.46 

 10.33 

 10.17 

 10.33 



11.33 

 11.25 

 11.17 

 11.00 

 10.96 

 11.08 



11.92 

 12.00 

 11.92 

 11.79 

 11.67 

 11.83 



12.75 

 12.67 

 12.67 

 12.50 

 12.42 

 12.50 



13.62 

 13.50 

 13.46 

 13.29 

 13.21 

 13.29 



14.46 

 14.29 

 14.21 

 14.12 

 14.04 

 14.12 



6.96 

 7.00 

 7.12 

 7.21 



7.38 

 7.46 

 7.58 

 7.67 



8.00 

 8.00 

 8.08 

 8.17 



9.25 

 9.29 

 9.42 

 9.50 



9.92 

 10.00 

 10.08 

 10.08 



10.75 

 10.75 

 10.79 

 10.83 



11.46 



11.46 

 11.50 

 11.58 



12.12 

 12.17 

 12.25 

 12.38 



12.83 

 12.88 

 12.96 

 13.04 



13.62 



13.71 

 13.75 

 13.79 



14.54 

 14.54 

 14.58 

 14.67 



8.50 



8.83 



9.33 



9.83 



10.42 



10.92 



11.67 



12.33 



7.50 



7.92 



9.00 



9.67 



10.33 



11.08 



11.75 



13.08 

 12.50 



13.71 



14.46 



15.29 



13.21 



13.92 



14.79 



6.88 

 6.54 

 6.33 

 6.33 

 6.00 

 5.92 

 5.83 

 5.62 

 5.62 

 5.50 

 5.46 

 5.46 

 5.42 



6.42 



5.42 

 5.25 

 5.17 

 5.12 

 5.17 

 5.50 

 5.50 



5.33 



7.38 

 7.08 

 6.88 

 6.79 

 6.58 

 6.50 



6.04 

 6.00 



6.92 



6.00 

 5.92 

 5.83 

 5.88 

 5.83 

 6.21 

 6.25 



6.00 



8.54 

 8.29 

 8.12 

 8.00 

 7.83 

 7.79 

 7.62 

 7.54 



7.50 



6.62 

 6.58 



6.62 



7.46 

 7.42 

 7.38 

 7.38 

 7.42 



8.17 



7.33 

 7.29 

 7.29 

 7.25 

 7.29 

 7.42 

 7.42 



7.33 



9.21 

 9.00 

 8.83 

 8.75 

 8.58 

 8.54 

 8.38 

 8.29 

 8.21 

 8.21 

 8.12 

 8.12 

 8.12 



8.83 



8.08 

 8.04 

 8.04 

 8.04 

 8.00 

 8.21 

 8.17 



9.92 

 9.62 

 9.50 

 9.46 

 9.25 

 9.25 

 9.12 

 9.08 

 8.92 

 8.92 

 8.83 

 8.88 

 8.88 



9.54 



8.83 

 8.83 

 8.75 

 8.83 

 8.75 

 9.00 

 8.96 



8.83 



10.67 



10.38 



10.25 



10.21 



10.00 



9.96 



9.83 



9.79 



9.67 



9.67 



9.58 



9.67 



9.62 



10.29 



9.62 

 9.58 

 9.50 

 9.58 

 9.50 

 9.67 

 9.67 



9.58 



11.42 

 11.17 

 11.00 

 10.96 

 10.75 

 10.67 

 10.58 

 10.54 

 10.42 

 10.42 

 10.38 

 10.38 

 10.38 



11.04 



10.38 

 10.33 

 10.29 

 10.33 

 10.29 

 10.42 

 10.42 



10.33 



12.17 

 11.88 

 11.75 

 11.71 

 11.46 

 11.42 

 11.38 

 11.25 

 11.17 

 11.17 

 11.17 

 11.17 

 11.17 



11.79 



11.17 

 11.12 

 11.08 

 11.04 

 11.04 

 11.17 

 11.17 



11.12 



12.88 

 12,58 

 12.46 

 12.38 

 12.29 

 12.17 

 12.08 

 12.00 

 11.96 

 11.92 

 11.88 

 11.92 

 11.88 



12.50 



11.83 

 11.83 

 11.79 

 11.75 

 11.75 

 11.92 

 11.79 



11.83 



13.62 

 13.33 

 13.25 

 13.17 

 13.12 

 12.96 

 12.83 

 12.75 

 12.67 

 12.67 

 12.62 

 12.62 

 12.58 



13.29 



12.58 

 12.58 

 12.50 

 12.54 

 12.50 

 12.71 

 12.67 



12.58 



14.46 

 14.17 

 14.08 

 14.00 

 13.96 

 13.79 

 13.71 

 13.54 

 13.50 

 13.50 

 13.46 

 13.46 

 13.46 



14.12 



13.42 

 13.38 

 13.33 

 13.33 

 13.33 

 13.50 

 13.54 



13.42 



14.67 

 14.58 

 14.50 

 14.38 

 14.29 

 14.38 



14.79 

 14.83 

 14.88 

 14.96 



15.96 



15.17 



14.71 

 14.46 

 14.33 

 14.25 

 14.21 

 14.04 

 13.96 

 13.83 

 13.79 

 13.71 

 13.67 

 13.67 

 13.62 



14.38 



13.58 

 13.54 

 13.50 

 13.50 

 13.50 

 13.67 

 13.58 



13.54 



0.73 

 0.72 

 0.72 

 0.73 

 0.73 

 0.73 



0.72 

 0.71 

 0.70 

 0.72 



0.65 



0.68 



0.71 

 0.71 

 0.72 

 0.72 

 0.73 

 0.73 

 0.73 

 0.73 

 0.73 

 0.74 

 0.74 

 0.74 

 0.75 



0.72 



0.74 

 0.75 

 0.75 

 0.75 

 0.75 

 0.73 

 0.73 



0.74 



17,500 



16,700 



15,800 



14,600 



13,800 



14,200 



15,900 



19,300 



19,400 



19,600 



24,100 



30,800 



33,600 



28,900 



23,200 



19,800 



17,400 



15,400 



14,100 



13,400 



12,000 



11,200 



10,400 



9,660 



9,310 



8,580 



8.120 



7,800 



7,380 



16,470 



7,020 

 6,900 

 6,540 

 6,540 

 6,720 

 7,860 

 7,680 



7,037 



1^/ Water elevation influenced by inflow into attraction channel at downstream end of attraction wall from spillage over 

 the dam adjacent to fishway. £/ Water elevation influenced by trap installation in fish exit channel. 3./ Average for pools 

 2 through 11, because of auxiliary water influence on water elevation in pool 1. 4/ Furnished by the "U.S. Geological Survey, 

 Water Resources Division, College Park, Md . 



dip nets in the fishway attraction channel 

 (fig. 4) and throughout the river from the 

 falls downstream to the bridge. 



FISH PASSAGE AND UPSTREAM MOVEMENT 

 OF ANADROMOUS FISH, 1962 



Observations were continued in the spring 

 of 1962 near Little Falls to determine the 

 upstream passage of fish through the Snake 

 Island fishway and to gather additional infor- 

 mation on the upstream migration by anad- 

 romous fishes. 



Fish Passage 



The fishway was operated on April 30 and 

 May 5 to 31. The fishway trap was lifted 

 68 times during these Z7 days at various 

 time intervals between 7 a.m. and 9 p.m. 

 Fish counted through the trap included 14 

 suckers; 18 bluegills; 63 catfish; and 1 carp 

 (table 3), No anadromous fish were trapped 

 or seen in the fishway system. Many suckers 

 and carp were observed passing over the 

 dam between Snake Island and the Maryland 

 shore. 



