If the time comes that you need to ford a river, you might be grateful to be familiar with some common techniques for this task.
Take your time to find the best place to cross
Take some time looking for the best spot to cross. At lower elevations, you might find a log that is safe to cross. At higher elevations, you might find boulders to hop across. Most of the time, it's safer just to wade through shallow water than to risk injuries from slipping and falling off of rocks or logs.
If possible, look for a spot where the river breaks into several braided channels. This will allow you to take a rest along the way.
At the same time, avoid narrow points in streams. Water is deep and it flows faster when the channel narrows.
When much of the water comes from snow and glacial melt, the stream will be lowest early in the morning. As the sun heats up the snow, the river will rise throughout the day. If it just rained heavily, you can expect flows to increase temporarily.
If there is no safe place to cross, then don't. Your sweet life isn't worth the risk.
Conditions may improve later, you may find a safer crossing upstream, or your hiking plans may need to change. All are better options than drowning.
Don't go beyond shin-deep when the current is fast enough to cause hydraulic jumps
It is easy to underestimate the force and speed of moving water. Use a stationary object -- a stick or hiking pole to look for hydraulic jumps. A hydraulic jump is when the water froths upward behind a stick rather than smoothly rippling behind. In case of the former, exercise great caution. Wading up to your shins in this current can cause water to froth up above the knees and even knock you over.
When water moves this fast, rocks can roll along the stream bottom, giving you no firm footing. Glacial runoff can be opaque with sediment, making it even more difficult to choose a safe path.
Once you're knocked down, it may be impossible to get up again, and your only option will be to swim.
If a stream is calm -- the water does not froth up behind a stationary object -- it may be safe to wade above the knee.
Streams tend to flow the fastest in the middle, just below the surface. They also flow the fastest on the outer corner of a bend.
Never ford a stream directly above a waterfall, rapids or a log jam. Choose a place where you have enough padding downstream to swim to the shore before things get too rough. Log jams are treacherous. The water pushes down here and can pin you underwater against branches and debris.
Before setting foot in a stream, unfasten your pack. You don't want to be fighting with straps if you're swept downstream and need to swim.
Frigid water will numb the feet and legs. It can be quite painful to go barefoot. If you know you'll be fording streams on a hike, a lightweight pair of water shoes can be a godsend. Otherwise, you need to weigh the pros and cons of getting your shoes wet. The wider or more dangerous the crossing, the more you may appreciate wearing your boots. Remember that soggy boots are better than falling. Dual layer nylon and wool anti-blister hiking socks can help to prevent blisters from wet boots.
Lose your pants and go bare legged if possible. Pants will increase the drag.
Solo crossing slow water
On a slower stretch of river shallower than waist-deep, it may be easiest to angle your crossing for 45° downstream. Use a stick or a hiking pole downstream to brace every step and probe for your next footing. Always maintain two points of contact at all times.
Solo crossing swift, shallow water
Most of the time, you will want to face upstream and lean into the current. Use a hiking pole or a sturdy stick to probe ahead for obstacles and dropoffs. Don't take a step until your stick is well braced.
Fording rivers with groups
Rule number 1: Never tie a rope around anyone. An attached swimmer will get dragged under the surface when the rope goes taut.
Group pole method
Find a strong pole long enough for several people to hold onto. Keep the pole parallel to the stream. Position everyone from lightest upstream to heaviest downstream. March across in a the river in a row, keeping the pole parallel to the current. The lightest person breaks the current upstream while the heavier people provide support below.
Another method works best in groups of three. Form an inward-facing circle. Each person should firmly hold the backpack straps of the person on either side. Take steps one person at a time. The other two people can provide support while they do this. Avoid doing this with more than three people. You'll lose the advantage of the upstream person breaking the current for those downstream.
Single rope hand lines for large groups
Ropes can make effective hand lines for large groups. Send the heaviest/strongest person across first, holding the rope.
Anchor the other end of the rope far upstream to provide a belay. There shouln't be much slack in the rope. If the leader falls, they can hold the rope to pendulum back toward the shore, where others wait to help.
Once the leader makes it across, untie the belay point. Secure the rope across the river between two sturdy points. Tie a slipknot on one end to help remove slack. Pull it taut and send everyone across, still using a pole, but with the rope as an extra handhold.
The last person to cross should be strong and heavy (the leader may need to cross back again). The belay procedure is then repeated, but with the rope anchored on the far side.
So you fell in, now what?
Never set foot in a river without having some plan of where you're going to aim yourself if you get swept downstream. If you're in a group, discuss this with everyone.
If you get knocked off your feet, slip out of your pack immediately. Don't waste time and energy trying to get back up. You probably won't be able to. You want to orient yourself feet-first, and then get on your back. You want to use your feet rather than your head to bounce off objects. Stay on your back so you can see what's coming. Try to steer toward the shore. As long as you don't drown, your next course of action needs to be staving off hypothermia.