November, 1954 
the lake and increase the turbidity. Dur- 
ing periods between rains, these clay par- 
ticles settle out, and the lake becomes 
clear. 
In 1942, the lake was most turbid on 
March 12, fig. 5, when a Secchi disc would 
disappear at 0.7 foot below the surface. 
Transparencies of less than 2 feet were 
recorded also on March 16, 19, and 22; 
on April 8, 9, and 10; on May 7; and 
on June 14, 15, 16, and 17. While all 
rains of as much as 0.5 inch influenced 
the transparency of the water to some 
extent, most rains of 1 inch or more were 
followed by periods of very low trans- 
parency of water, showing Secchi disc 
measurements of less than 2 feet. Such 
low transparency, during the fishing sea- 
son, interfered with fishing success. Once 
the transparency approached | foot, about 
5 or 6 days free from rain were required 
for the water to reach a maximum of 
transparency. 
The amount of silt entering the lake 
and the muddiness of the water varied not 
only with the condition of the vegetative 
cover on the watershed (influenced by the 
seasons) but also with the type of rain- 
storm. For example, on June 26, 1942, a 
rain of 2.0 inches was recorded as having 
fallen throughout a period of 10 hours; 
transparency readings made on that day 
and on days following showed that the 
lake had greater transparency on the first 
and second days after the rain than on the 
day of the rain. In another instance (Sep- 
tember 19, 1942), a violent rain of short 
duration amounting to only 0.65 inch 
caused a drop in transparency from 10 
feet to 3.7 feet, apparently without rais- 
ing the water level of the lake. 
The maximum transparency of the 
water was measured at 14 feet on June 
4, 1942, after 15 days of little or no rain- 
fall. Later, in the summer and fall of 
the same year, water transparency did 
not exceed 10 feet. During this period, 
the transmission of light was reduced by 
plankton (mostly blue-green algae) rather 
than by particles of clay. 
In 1942, the water level of Ridge Lake 
never dropped lower than 0.4 foot below 
the overflow lip of the tower spillway. 
The drainage basin of 1.41 square miles 
(902 acres, or about 50 acres of drainage 
jbasin per acre of lake) is large enough 
BENNETT: LARGEMOUTH Bass IN RIDGE LAKE 223 
to fill the lake basin with runoff water 
from normal rainfall several times during 
a single year. Even in late summer, a 
time of infrequent rains, the runoff is suf- 
ficient to prevent severe drops in the lake 
level. 
The tower spillway, fig. 2, which re- 
moves water from the bottom of the lake, 
has a capacity of 25 cubic feet of water 
per second. If the water inflow from the 
drainage basin exceeds this capacity, the 
level of the lake rises and, if the lake level 
exceeds the crest of the surface spillway, a 
foot higher than the lip of the tower 
spillway, the water flows over into a 
stilling basin and then into the section of 
Dry Run Creek below the dam. The 
capacity of the surface spillway is so 
great that runoff waters from even the 
heaviest rains do not create a flow of 
water exceeding about a foot in depth on 
the crest of this spillway. Within a mat- 
ter of minutes after a rain, or at most a 
few hours, the lake level drops below the 
crest of the surface spillway. 
In 1942, the water level of the lake 
rose above the crest of the surface spill- 
way eight times, fig. 5, after rainfalls of 
approximately 1 or more inches. Water 
continued to run out of the lake through 
the tower spillway all through the spring 
and summer until August 22. On Sep- 
tember 8, a rain of 2.2 inches, which feli 
during a period of 12 hours, raised the 
water level in the lake 0.7 foot, and water 
again flowed through the tower spillway. 
The maximum fluctuation of the lake 
level throughout the spring, summer, and 
fall of 1942 was 2.5 feet. 
Thermal Stratification and Dis- 
solved Oxygen.—Ridge Lake would 
probably show characteristics of a eutroph- 
ic lake except for the occasional loss of 
substantial quantities of water from the 
lower strata following heavy rains. As 
mentioned previously, an inflow of runoff 
water from the lake watershed in amounts 
large enough to cause a significant rise in 
the lake level above the lip of the tower 
spillway is followed by a loss of water 
through that outlet from the cold, oxygen- 
deficient stratum immediately above the 
lake bottom. Except after rains so heavy 
that water flows over the surface spill- 
way, the volume of bottom water lost is 
approximately equivalent to the volume 
