In conjunction with the paver sidewalk question posted earlier, I have another engineering question. The patio for the project is slated to be expanded, and unfortunately there is an old cistern that might cause me problems. I might be able to go out and encompass the cistern into the patio using the old hand pump as a focus feature, but I'm afraid that if I'm too close to it, that I'm going to have issues with the foundation of the patio and wall retaining it. If I fill it in, I'm wondering what material to use. Back where I'm from, there was an old hand-dug well in the yard, and we filled it in with Lime. Yes there was some settling, but I contributed that to the concrete that was added to the out-side of the well and was removed. Also, I do believe that it is dry-laid, brick lined. There is another old well on the property with that set-up and I'm guessing the cistern is the same way. I'm able to look into the top of the old well and see that the lining is still intact perfectly and has taken tractor traffic being close to the old barn. Any thoughts ???