To make a river stone mat first you have to gather or purchase river stones. After that take a plastic mat and arrange all the stones on it. Then stick all the stones one by one to the plastic mat by using silicone sealer. Let the sealer dry completely.
Use an old tire to create a small backyard pond. My kids, 3 sons, have been helping with yard work and planting. They keep asking for a pond. I think this is a great DIY project to do outside with them. Looks simple.