I can identify with your flooding problem. Our whole piece of property is on a low rise . Our houses sit on the top basically so the property drains to the back on the south end, that 's where all our out buildings....saw mill, DH's new shop, the little barn and the chicken house and yard all sit. The north side of the property drains mostly to the road and some into the folk's yard. But the worst of it runs down to our buildings. When we tore down the old storage building that had stood where DH's new shop is there is about a foot of difference in the soil level where the base of the old shed sat. That's soil that has been slowly carried down the property over ten years. No wonder I have roots on the surface al over the front in the dog's yard...all the dirt is down by our buildings.The water will drain onto their property, they own the whole lot on the left side of my house. As my house is on the left fence, halfway between front and back yard, the only place to run a drain is onto their side. My back yard is the lowest point in my yard, I have brought in truckloads of dirt, but it isn't enough yet, plus the dogs love digging back there. Every other part of my yard drains towards the street, except the back because the house is in the way. That corner of my house is also sinking, because of the flooding. So a small PVC pipe with screen on both ends will be installed and run under the fence to help drainage. I will probably add some more dirt, but looking for a more mud like soil than regular topsoil this time.