The topography of the Basin and Range region was largely formed by faulting , not by river erosion .
Many of the basins have no outlets , meaning they will fill up with water like a bathtub until they overflow into the next basin .
Since the topography of the Basin and Range region was largely formed by faulting , not by river erosion , many of the basins have no outlets , meaning they will fill up with water like a bathtub until they overflow into the next basin .