The fish are left over from ancient Lake Bonneville which receded about 14,000 years ago. Several natural springs feed the wetlands. These are along a linear path at the range front (that is, fault controlled), and include North Springs, Deadman Springs, House Springs, Middle Springs, Thomas Springs, South Springs, and Percy Springs. Fish Springs is thought to be the end of a long flowpath of groundwater, starting in the Schell Creek Range and Snake Range area and flowing along permeable bedrock (for example, limestones) or faults toward Fish Springs. This comes from the fact the annual discharge of the springs is /year, and the annual recharge for the drainage area (the range front and Fish Springs Flat) is about /year, meaning over 6 times more water flows out of the springs than falls in the valley annually by precipitation. The springs and several wells in the area are monitored by Fish and Wildlife personnel and/or the Utah Geological Survey. The water of Fish Springs is not suited for human consumption, being warm (~) and highly saline.