This morning, I'm heading to TSC to buy a semi-trash pump. I'm going to have to drain the small pond and repair leaks before continuing. I thought I had the leaks slowed, but with added water in the pond they began to leak through the "sand pipe" and into the 2nd pond again at an increased rate. My wife asked me if the 2nd pond being full would stop the leaks, but I told her that the 2nd pond would never be as deep as the sand layer, plus the layer is leaking out in many directions with only a small amount of the leakage going into the 2nd pond. For every gallon I see appear in the 2nd pond, there's probably 100 gallons that go underground and disappear. The first picture below illustrates what is happening. I sealed the red portion of the dam, but the sand layer continues and water is bypassing my clay seal.
The final straw this week was seeing a seep appear at the opposite end of my new dam where it ties in with the slope. Even though I have a key trench notched well into the slope, the water is just going around that notch in the sand pipe and then showing up as a seep as shown in the 2nd photo.
I'm going to drain the pond and fix the leaks with a thick clay layer. I may even add some bentonite clay since I have a source nearby. I want to get it fixed right so I don't have to worry about it anymore.
On a positive note, I've completed the final level of the 1st pond to include spreading sod filled clay soil on top to get grass going. The 2nd dam is also in the finishing stages. I can now start working of the final cleanup. I have lots more to do, but this is a major milestone. I'll post photos of the dams soon.