234 ILuinois NaturAL History Survey BULLETIN 
1943 as unmarked fish (see page 241). 
Attempts to seine this ditch were futile 
because of the hip-deep mud. 
By the time of later drainings (1945, 
1947, 1949, and 1951), silting and slough- 
ing-off of the banks had reduced the depth 
of water in this blind channel to 3 inches 
or less; here large fish, the backs of which 
could be seen readily, were caught with 
dip nets. Some small fish probably have 
escaped each census by staying in this 
blind channel. Poisoning of this channel 
was considered impractical because fish 
held in the spillway basin had to be re- 
turned to the refilled diversion ditch in 
the lake basin after only a small volume 
of water had collected behind the gate of 
the outlet valve. 
Vol. 26, Art. 2 
An attempt in 1949 to poison Dry Run 
Creek within the lake basin was a fail- 
ure, presumably because of the low water 
temperature. It is probable that none of 
the toxicant entered the blind channel 
near the dam, as the outlet valve was not 
kept closed long enough for water to 
back up into this channel from the diver- 
sion ditch. 
On each census after the lake was 
drained and all fish were collected (that 
could be collected), the outlet valve was 
closed and water was allowed to collect 
in the diversion ditch above this valve. 
When this ditch was bank-full of clear 
water for 150 or more yards above the 
valve (usually about 12 hours after the 
valve was closed), the amount of water 
Fig. 10—Handling fish at Ridge Lake. When Ridge Lake was ready for restocking after 
a draining operation, selected fish to be returned to the water were handled in lots of 50 to 100. 
The fish, held in the stilling basin at the lower end of the concrete surface spillway, were 
captured and placed in a stock tank (left of center). From this they were removed indi- 
vidually and weighed, measured, “scaled” (had a few scales removed for later age determi- 
nation), marked (fin-clipped), or had previous marks recorded, and placed in a second stock tank 
(lower left). When the second tank became crowded, the fish were transferred quickly to 
covered tubs on a horse-drawn sled, hauled over the dam, and replaced in the lake. 
