This is Lake Tuendae (to be beheld) at the Desert Studies Center, Zzyzx. In the center of the lake is an island with a fountain. The name of the island in Enrico Caruso Island.
Enrico Caruso Island is named Enrico Caruso Island in honor of Enrico Caruso but not Enrico Caruso the famous singer but the Enrico Caruso who built Enrico Caruso Island was named for the legendary Enrico Caruso and named it Enrico Caruso Island for himself.
Rather than growing wider and emptying into the sea the Mojave River becomes smaller and smaller finding its way in the sand between the cobbles and rocks curling into crescent -shaped dark meanders and swales transitioning to dry sand and finally, collections of same sized stones.