"Don't look at the water!" That was my father-in-law's advice to my wife, Emily, as our horses picked across the rocky bottomed swift stream.
The horse, Elmer, had never been particularly fond of taking unscheduled swims. I learned many years later that he and a neighbor had once upset a wagon in the middle of this same river.
Fording the stream at high water, pulled by a team of draft horses, they'd experienced a near-fatal wreck as the current shoved the wagon sideways and then pushed it over. Luckily, both men and horses survived.
My father-in-law's advice to Emily was geared at preventing vertigo. Looking down at the water rushing by can bring on dizziness in some riders.
We're used to the surface under our horses being stable from side to side, but water rushing underneath our mounts can have a disorienting effect. It's as though the "ground" under your horse is moving rapidly sideways.
The best solution for riders susceptible to dizziness while crossing swift streams is to look straight forward, vision fixed upon the spot on the far bank where you intend to leave the water.
The principle is the same as in discouraging sea sickness on a boat, where you're advised to look at the horizon, a fixed point.
The other reason for fastening your vision on the far bank is that your horse will be helped by your straight-forward posture. Becoming preoccupied with the water leads to imbalance in the saddle. If you stay straight, your horse is more likely to as well.
See you on the trail!