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12 Chapter 3-Causes and Impacts of Sallnlly N W <Xl o resulting salinity of spoil derived waters ranges from approximately 3,000 mgIL to 3,900 mgIL, The variability in concentration depends on water residence time and the chemical and physical properties of the spoil. Saline water is also a byproduct of oil and gas production in the Basin, It is not uncommon to produce several times the amount of saline waters as oil. Oil and gas operators in Colorado produced approximately 25 million barrels of saline water during December 1985, The salinity of production waters varies greatly from location to location and is dependent upon the producing fonnation, Common disposal techniques include evaporation, injection, and discharge to local drainages, The future development of the oil shale resources in Colorado, Utah, and Wyoming has the potential to increase salt loading to the Colorado River, Salt increases can be attributed to the consumptive use of good quality water, mine dewatering, and, if surface retorting is used, the leaching of spoil materials similar to that of surface coal mining, Reclamation and others are attempting to identify abandoned exploration wells that are leaking and develop plans to control the leaks, The Meeker Dome Salinity Control Unit identified and plugged several abandoned wells along the White River to prevent a salt dome (a geologic formation) from discharging saline water into the river, Erosion Several researchers[8-11] have shown that erosion of saline shales and dissolution of effiorescence (surface salts) increase salinity during thunderstorms, Low-elevation snowmelt on saline geologic fonnations may also contribute significantly to salinity, Analyses of the Green River near the Green River station indicate that salinity remains unusually high during peak flows associated with snowmelt runoff events, Reclamation studies on the McElmo Creek Salinity Control Unit found that approximately 32 percent of the total salt load could be related to runoff events, Other studies by Reclamation show that 21 percent of the Price River salt load and 14 percent of the San Rafael River salt load are related to natural runoff events. Studies[12] conducted on Mancos Shale in the Upper Colorado River Basin have demonstrated a positive relationship between sediment yield and salt production, Sediment yield increases as a result of either upland erosion or streambank and gully erosion, Upland erosion is attributed to rill and inter-rill flow, Salt and sediment yields are dependent upon stonn period, landfonn type, and the soluble mineral content ofthe geologic formation, Studies[13] conducted in the Price River Basin have demonstrated that the highest salt and sediment concentrations occur in the first streamflow event following a long period of no discharge, The accumulation of salts in the channel is attributed to eftlorescence resulting from the drying of the channel. Salt yields occurring after the initial flushing of the channel are similar to those found in the surrounding watershed soils, Sediment and the resulting salt yield are highly dependent upon landform type, Three major landfonn types-badlands, pediments, and alluvial valleys-are associated with the Mancos Shale terrain, Badlands are the most erosionally unstable, with sediment yields as high as 15 tons per acre [14], Rilling accounts for approximately 80 percent of the erosion[13], Because salt production is closely related to sediment yield and the badland soils have not been leached of their soluble minerals, they produce the greatest amount of salt of the landform types, Pediments are gently inclined planate erosion surfaces carved in bedrock and generally veneered with fluvial gravels, The surface slopes of pediments are gentle, making them relatively stable, Pediments have deeper soils and higher infiltration rates than badlands, thus they support a greater vegetation cover and are less erosive, Alluvial valleys are formed by a change in gradient and the deposition of sediment, They are stable except along the channel where