I still use the old method of drowning wire like you describe. Much lighter and more convenient to pack, and I can cut it to whatever length needed at site (unlike rods or drowning cables that are predetermined lengths). If the bottom is rocky and you can't drive a drowning stake in, you can use a weight, if there are rocks available the most convenient weight if you have to travel any distance from the truck is a gunny sack that you can shove in your back pocket and then fill with rocks at the site and tie the wire to it.