It sounds like that would be caused by the defrost drain being clogged or frozen. If the defrost drain is frozen, the water will overflow the drain trough and drip down to the bottom of the compartment. If the defrost drain is frozen, thaw it out and ensure that the drain is clear of debris.
Safety Warning. Before beginning your repair, disconnect power to the refrigerator by either unplugging it from the wall, or turning off the power source at the breaker. I recommend you also turn off the water supply to the refrigerator.
You can clean the tube with a solution of 50% warm water and 50% bleach. Be careful with the bleach as it can damage you skin and also the floor. If you see any cracks in the tube, or it doesn't come clean, you will want to replace it. I have included the link to order the part.
Next, I recommend you locate the drain hole inside of the freezer section. You will need to remove the bottom freezer basket. If you do not see it on the floor of the freezer, then it may be behind the Evaporator Cover. The drain hole will need to be cleared as well. Use the same 50% warm water and 50% bleach solution. To make it easy to pour the cleaning solution in the drain tube, use a turkey baster. Cleaning the drain system should be a part of your regular refrigerator maintenance. A good reminder is when you clean the condenser coils, clean the drain at the same time. I have included the link for a coil brush in case you don't have one: searspartsdirect.com/product/bwevwmy5hu-0022-022/id-pm14x51