Extra ground wire carrying current

Hello, I have taken the steps to mitigate stray current on our cable line, our stove top, and from our water main but have still been battling effects within our home.  I just found that we had amperage on a ground wire that comes out of our electrical panel and bonds to a water pipe about 10 feet away. What is the purpose of this extra ground? Can it be removed? Maybe it's how the house was grounded many years ago? 

Please note, we have stray current that occurs with our clothes dryer and we haven't been able to get that a new circut yet. Electrician said that the wiring wasnt strong enough to do without a whole new circuit.. When we turn this on, amperage basically goes on every metal clad circut I can measure, but most or it goes on this ground wire.

I unscrewed the extra wire bond to the water pipe and the amperage went away at that point, but if I measure closer to the panel, I still get an amperage reading. Kind of scary. Where does it go?  What do you recommend? I have attached photos and would be interested in a phone consult if you think that would be easier. Thanks!