Where does surface water collect if it does not flow to the ocean

If surface water does not flow into the oceans, then it will be collected into lakes or wetlands for instance in marshes and swamps. Also, Drainage basins collect surface water and direct it on it gravitationally.

If surface water doesn't flow to the ocean, it means land is flat, and if land is flat then more and more water will get absorbed by the soil and underground water level will increase, well, lakes etc will increase.