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o ';:i) l'" N , - -' o LITTLEFIELD SPRINGS The investigation began with the intent to control the salt discharge into the Virgin River from the saline springs emerging between the Virgin River Gorge and Littlefield, Arizona. They are loosely referred to as Littlefield Springs. Accordingly, water sam- p 1 i ng and other hydro 1 ogi c ana lyses were concentrated at and above Littlefield, shown on Figure 1. It was found that in combination, the river and the springs have a unique relationship. During periods of low flow, from May to October, the Vl rgi n Ri ver percolates underground upstream of the gorge. Surface flow begins to reappear about 2 miles above the mouth of the Virgin River Gorge in the form of springs discharging from the riverbed and from the adjacent banks. Flows of 20 ft3/s at an average salinity of 2,915 milligrams per liter (mg/L)lJ were measured at the mouth of the canyon in 1973. At a point 2 miles downstream, the flow increased to 43 ft3/s with an average salinity of 2,900 mg/L. The stream continues to gain, and at the USGS gaging station at Littlefield the flow was 70 ft3/s and the salinity decreased to 2,470 mg/L. The salinity improvement is attributed, in part, to an inflow of about 3 ft3/s of good quality water from Beaver Dam Wash and from springs along the north bank of the river above the gage. Individual springs ranged in discharge between 0.01 ft3/s and 3.0 ft3/s and emerged from rocky sections of the stream bank. Historic discharge had deposited substantial reefs of calcium carbon- ate at the mouths of some of the springs. A hydrogeologic investigation was completed in 1979 [4] to detemine the source of recharge to the Littlefield Springs. It was found to occur within three zones; (1) mountain zone, (2) mountain- 1/ Salinity values are based on summation of ions, determined by laboratory analyses. 11