My Dad built a small run in shed for a few animals when I was young. It set in a small depression. Later we added another section to the barn for more animals. Still later I wanted to dairy so we converted it to stantion barn. We tried to move enough dirt to keep the water from running into the barn. Never did happen. One night after a very hard rain, I checked to see that the barn was full of water, and the bedding was floating. Let the cows out, water went down, completely swept it out and started back with new bedding and feed. It's up to you, but I'd find a differnt spot.