Lime dust would be a bad option for a yard with dogs. If you or your dogs inhale the dust, it will burn your lungs, and you will be coughing for months. (I found this out when I spread about 30 bags on a large garden, by cutting the bags open and pouring them out.)
Here is a good,, but expensive, solution. Have you though about a fence, maybe three feet tall, made of hardware cloth? (Hardware cloth is what you see on the bottom of rabbit cages; it is welded wire, with squares of only 1/4 inch each. It is very very strong). I believe you can buy it in rolls that are 36 inches wide, or 48 inches wide.
Using treated lumber, build a good fence framework 36 inches to 48 inches high, along the back of your yard, and then staple the wire in place using galvanized fence staples. Make sure you dig a trench about 4 to 6 inches deep along the fence line, and puts the wire 4 to 6 inches deep into the ground. (You will probably need to build a gate in the fence, to have access to your lake.) Run the fence along the lake front, and about 15 yards up, on each side of back yard. Clear out any underbrush for six feet on both sides of the fence, and keep it cut short. Spray the fence with round-up every three months, to make sure that no vines or weeds grow up into it. Then, spread white chipped marble along the outside perimeter of the fence, at least two feet wide along the fence line. (This will make it really easy to see a snake that is lying along the fence line.)
Yes, I know that a big snake can climb over a 36 inch tall fence, but I'm betting that 95% of them won't, and you will find them curled up against the outside of the fence. Make a quick patrol every morning and evening with a shovel, and just chop the shovel down on the far side of the fence to cut a snake in half.
The one-in-ten snake that climbs the fence can be handled by the dogs.
No matter what this costs, I would do it. Having poisonous vipers in the backyard would be intolerable to me. I simply couldn't live with it.
Regards,
Mannyrock