Anne Henage and I took the Labor Day Water samples on Friday, August 24 between 11:30 and Noon. Preliminary results are as follows:

#1 Dock 24 cfu
#2 Cedar Fork Creek 26 cfu
#3 Booker Creek 21 cfu

Caution level is individual reading above 400 cfu, or average above 200 cfu.

Lake water temp:
30 C, 86 F (Dock)
31 C, 88 F (Cedar Fork Creek forebay)
31 C, 88 F (Booker Creek inlet arm)

Our testing looks for one kind of bacteria that is an indicator for the general safety of the lake water for recreational use. “Water Quality” is a subjective thing. The aesthetic qualities of the water and the bacterial count do not have a direct relationship. Our lake water is in very good condition especially considering that the tributaries are dry and have been so for almost a month. Many other lakes and ponds in the area have turned the color of old antifreeze, and have what appears to be the consistency of pea-soup.

The lake level is down almost a foot. The stream continues to flow below the dam. Having movement in the water, even if the lake level is falling, keeps it from stagnating. There is a large but dwindling thermocline in the middle of the lake-park end of the lake. The lake is like a layer-cake of different water temperatures, and the cool water below the surface is coming from an underground spring located about 20 yards beyond the far dock and maybe 80 yards to the left. The flow from the spring is less than what bypasses the dam, so the lake level is dropping. The thermocline shrank by about 50% in area during the last week, That means our spring is slowing down. .

I checked the water clarity with the SECCI disk and the reading I got just beyond the swimming beach was 25 inches. That is only a little worse than it was in June, generally good for this time of year. As always, use common sense about going in the lake. If you are concerned, take reasonable precautions. Lake water in NC never gets sparkling clear like it does in other parts of the world.

I expected to find the lake a lot nastier than it is. After an algae bloom, there is a die-off and it looks like a rain of black debris under a surface that is too glassy. The SECCI readings are 1 foot or less. At the present surface temperature (86-88F) , it could turn suddenly. For the time-being, we have none of the bad water quality problems that I described. Sometimes there is a dusting of crud on the surface that looks like goose down. I think goose down is an ingredient when this happens, but not the only one.

The ground water has a fair amount of dissolved solids, and the local clay has a lot of iron. That is what I presume gives lake water a yellow-to-brown cast. Local potters like our high-iron clay. Rain dilutes this, evaporation concentrates it. When it rains after a dry-spell sometimes the lake looks orange. That signifies an infusion of new silt. I think the other choice for water color is pale green from free-floating chlorophyll (algae and weeds). There are relatively few times of the year when the lake doesn’t turn white swimwear yellow, green, or brown. None of this is harmful.

Eastwood Lake seems to track University Lake, our drinking water reservoir in terms of color and what lives in it. About ten years ago, someone said that we share a species of brown mussels with University Lake that may be unique to this area.

Chuck Henage