Need help with drainage in back yard

I wrapped concrete around the back of my house for decorative and drainage purposes, but on one side I cant figure out how to complete the drain. The pre-existing drain is higher than I can make the new drain to allow proper drainage when I tie into the existing drain. It would cost way too much time and money to completely redo the entire thing, so is there any ideas on how I can get the slope needed in the new line to allow it to drain into the old line? I could pour an extreme amount of concrete to get the height, but that would cause a lot of new problems. Thanks for your time.

First, do you know where the old line drains to and can you run the new line to a lower point on the old line. The other option is a dry well if you have a spot to put it.

The lower point in the existing line is not accessible due to a concrete floor. What exactly is a dry well?

A dry well is basicly a hole a couple of feet around and up to six feet deep and filled with drain rock to help disperse the water. The depth depends on how much water and how fast a dispersal you are looking for. The drain rock can also be coverd by filter paper topped by bark or 6" to 8" of soil and sod.

Have you thought about pump drainage?