When comparing lakes, water clarity is one of the most important considerations. Who wants to swim in green turbid waters?
When I sought to measure water clarity, I thought I would have to submit samples to a lab. Turns out measuring water clarity is a simple enough process that I paid my 9 and 7-year-old daughters to do it for me.
All you need is a Secchi disk ($25 @ Amazon):
The technique for measuring is simple:
- Choose a sunny day with calm waters.
- Measure when the sun in right on top (10 am to 2 pm)
- Lower the disk until you no longer see it. Then bring it up until you can see it again. Do that a few times. Settle on the average in between the two, and leave your finger on the rope.
- Using a measuring tape, measure from the disk to the finger on the rope.
The measurements my workers got ranged from 55 inches on the shade side of the dock, to 68 inches on the sunny side.
So how do 65 inches compare to other lakes in Nebraska? First let’s convert to the metric system: 65 inches= 1.65 meters
I found this website that has historical information on 3 nearby lakes:
- Cunningham lake, 1997= 0.5 m
- Standing Bear, 2008= 0.68 m
- Hawaiian Village, 1996= 0.91 m
But what about the rest of the nation? I found this study of close to 1 million Secchi measurements around the US:
- The 25th and 75th percentiles for Nebraska were 0.2 m and 1.1 m, with the max depth in the state being 2.9 m. Mallard Landing is then around the 90th percentile, not too bad…until you compare it with the rest of the nation!
- Oregon seems to have very clear waters as their 25th and 75th percentiles are 1.2 m and 6.1 m, with the maximum being a whopping 31 meters! Other clear water states with 75th percentiles above 5 meters include Maine, California, Alaska, Montana, New Hampshire, and Vermont.