Throughout much of the "oil patch," water truly exemplifies the economic, sociologic, political and ecological lifeblood of the community. The permanent supply of usable water, on which the arid West depends for survival, faces many hazards. Currently, much available water exceeds or is rapidly approaching Public Health limits, and the tolerance level of the inhabitants.

Water enters an area as river flow or rainfall. It goes underground by natural seepage or irrigation where it percolates until it surfaces at natural springs or wells (domestic, irrigation - municipal or industrial) to re-enter surface flows. Normally, the cycle is repeated many times. Each cycle degrades the water quality. Although oil field operations contribute a small proportion to total degradation of the hydrologic system, each incident of oil field pollution is specific and highly newsworthy. When attempts to clean-up waters are made, the oil industry provides the first and most vulnerable target. Oil field practices can and do pollute water, mainly by increasing total dissolved solids (principally chlorides and sulfates), but also by releasing crude oil.

Ground water pollution is often difficult to prove and may not appear immediately. Conversely, its effects may persist for many years. Pollution may occur from:

  1. Evaporation Pits. Regardless of the concentration of brine entering a pit, the only substance leaving the pit by evaporation is pure distilled water vapor. Everything else remains behind forever or enters the water system either by seepage through the bottom of the pit or overflow. In Colorado during 1969, 27,000,000 barrels of water (1,110 to 35,000 ppm salinity) went to unlined pits. A 1966 detailed study of a ground water basin in NE Colorado showed that one small brine pit contributed a 27 ppm per year salinity increase to the entire ground water basin.

  2. Insufficient surface casing. Any surface casing which is not set below, and does not seal off all fresh water aquifers constitutes a pollution hazard.

  3. Any injection system. Waste disposal or water floods constitute a hazard; not only from casing leaks but also from cross-formational flows through natural or induced fractures.

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