Clear Creek fluid mechanics
 

With 40-acres of park and trails, and after much tractor and chainsaw work I've been picking up deadwood, cutting major branches with a hatchet, pruning, trail work, and mowing.
At the end of the day I reward myself with a swim in the shade of mighty oaks and pecan trees along our bordering Clear Creek to compensate for a day's immersion in the 100-F + heat.
The creek is running clear and I've amused myself 'testing' submerged 'sand dunes', various rocks, cans, and bottles in the flow, ala Leonardo di Vinci's sketchbook.
The sandy bottom provides ' flow visualization' by entraining loose sand and detritus into the wakes of the angled and contoured 'dunes', plus any stones or junk laying in the creek bed. You can 'feel' dead water in the lee, plus observe separation lines and turbulent wakes with the sand and debris. By angling the stones at varying degrees of attack, one can observe when the flow separation ends. Different shapes produce different effects. No snorkel or mask are needed. Also, by orienting my bodies frontal area and drag coefficient, I can either resist being carried away by the force of the water, or be dragged along with it, borrowing from past days surfing.
Minnows appear to be attracted to,and nibble at body hair. I recommend it as fish bait.
Yep! I'm a sick puppy alright. Cheap thrills and full-on geek. Neighbors will never know. Unless they catch me dragging wind tunnel models down there. Hopeless!:)
Sure does help with the heat though.

Newton has nothing on you I see.:D

A lucky guy lives in an area where he can swim in a creek. I miss it.

Call the police, there is a grown man playing with toy cars in the creek again and pouring milk upstream of them.

Nikola Tesla invented the bladeless turbine when he was ~4 years old, with a disk on an axle over a creek.

Then there is Viktor Schauberger and his Implosion Energy.

channel flow and riverbank
 

A year ago, we finally had an oxbow blowout, after 40-years of thunderstorms, and about a mile of former creek is now a lake. The two active riverbanks are a random assortment of shallows, sand, gravel, islands, stranded trees, tires, major appliances,personal belongings, and chasms. So far, there is nothing intuitive to be deduced from the distribution.
During storm floods though, the muddy, 'cappuccino' water and flotsam does reveal horizontal gyres and vertical roiling, which suggest submerged dynamics, reshaping the riverbed. Really powerful. Dangerous.Same mechanism as is presently eating away at the polar ice shelves.
As kids, my brothers and I were stupid enough to sneak into these kinds of waters, when storms hit Reseda, and Woodland Hills, California; before everything was concreted over, and fenced off, as part of the L.A. River complex.
A miracle to make it out alive.

Sounds like you are returning to your childhood.

Bravo.

May you never be old, only older.