Friday, February 28, 2014

Detective Hodge Solves the Mystery of Cooling Water Temperatures

I posted last on Friday morning a week ago and it is Friday morning now. Then, I was planning another trip to the Pond of Perpetual Pumpitude. Friday last, I did indeed go back for my third swim of that week and the water had warmed all the way to 64 degrees. I got in with my wetsuit but without the hood and the extra duct tape on my face. I even tossed my gloves onto the bank after wading into the water. I swam nonstop for one hour and thirty-seven minutes. That came out to 3.21 miles at a 30:18 pace per mile. That's a pretty good tempo for me, but it is suit-aided, so I don't know if I should be happy or not. OK, I'll be happy.

I even came back Saturday, but to my dismay, despite a warm and sunny day, the water had cooled a full two degrees rather than warming as I had expected. I only did 1.34 miles because my mojo had blown away in the blustery day, and I swear it felt like the water was getting colder as I stroked along. While swimming, I also noticed that there was no warm side/cold side as there usually is when the sun shines and the wind blows on these ponds. The air temp was 65 and the sky was as clear as a new pair of goggles, so the water should have warmed. But it didn't. When I tapped out and checked my thermometer, it read 61!!! Dude, it dropped a degree in twenty-eight minutes, and I could feel that degree while I was out there in it. How is that possible? *Rubs head and debates with self. Shall I write this?*

When I was a non-traditional student driving a $200 pickup truck and writing papers as well as tuition checks, I became an expert on cheap motor oil. I would mix 99 cent transmission fluid with cheap non-detergent oil to create an inexpensive but good tank mix designed to keep my 1971 GMC pickup truck from locking its engine. It worked. It worked for thirteen years. I did this so often and for so long that eventually when I lost my funnel, I became proficient at puring in the oil without the funnel. Then, when I lost my oil cap-- you know that thing on the valve cover that keeps the oil in the engine-- I discovered that I got better oil mileage without the cap, so I never bought another one. And finally, I added oil so often that I got where I no longer needed to wait for the valves to start clacking to signal me that I was two and a half quarts low before stopping to add oil; I just intuitively knew when to pull over and do a tank mix. I was proud of my hard earned oil knowledge, but I am grateful that I no longer have to use those hard won facts.

Since I have grown up and gotten a job and now have time to play, I have become an expert on catfish pond water temperatures. A few facts: 1) When the sun shines and the wind blows, normally a fish pond will develop a warm side and a cold side. 2) This warm side can be very warm as in hot. 3) This warm side will steadily get warmer as the day wears on. 4) The sunshine has as much, sometimes more, effect on the water temp than does the air temp. 5) The water temp can be higher than the air temp, even when the air temp is rising, not falling. 6) If the wind is blowing across the short side of the pond, the water can cool on a warm and sunny day.

Number six is what I learned last Saturday. Think of the ponds as large rectangles. Either by design or accident, the wind normally blows the length of a pond not across its width. The sun warms the surface water and on a typical day, the sun-warmed water is blown to one end where is continues to heat. The greater pond height on that end causes upwelling on the other end. The water coming from the bottom, especially in the winter and spring, is cold. Hence, a warm side and a cold side develop. One day last spring while I practiced in a pond, the wind changed directions by 180 degrees. As I swam lap after lap, the warm side and cold side slowly swapped with the change of wind direction. On the formerly warm side, there would be painfully cold spots as the water was pushed up from the bottom to the surface. The formerly cold side, where I climbed in and where my thermometer was, warmed up by twelve degrees while I swam. Twelve degrees!

Saturday, the wind blew across the width not the length of the pond, and while I expected one side to warm and one to cool, they both seemed to cool. My thermometer confirmed my sensation that the pond was cooling while I swam on that warm, sunny afternoon. Why? I surmise that with a cross wind, the surface water didn't have sufficient time to warm before being forced under. Thus, the upwelling was effecting both sides of the pond, cooling the entire surface to my dismay and discomfort.

You always wondered about that didn't you? I thought so. Anyway, for the week of 2/17-2/23, I

swam 14,170.84 meters,
ran 15.8 miles,
lifted weights two times, and
walked 4.44 miles.