2013-12-17_PERMIT FILE - C1992081 (18)

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• Ground Water Suitability. The constituent concentrations for wells HGDALI, HGDAL2, and HGDAL3 presented in Table 7-1 through 7-3 ware compared against agriculture water quality ar°^~+-~+° . promulgated by the Colorado Department of Public Health and Environment (CDPHE) to assess the suitability o£ the water for agricultural uses. In addition to the CDPHE sr°^.+=..+°, select constituents (TDS and SOS) xarg cou~ared against Wyoming Division of Environmental Quality (YIDEQ) standards as reference guidelines for specific agricultural uses. The WDEQ standards, while not promulgated in Colorado, era widely used within the industry ss use-suitability guidelines. The WDEQ sta^.d~^'+° are o£ interest because they set guidelines for two separate agricultural uses; one list o£ s*a^'+~+++~ (or guidelines) for irrigation use and a second (lase atrinyent) lint o£ standards (guidelines) for livestock use. In contrast, CDPHE's ground water agricultural sr°^~+=+•+° are generally for irrigation of crops. Ground water trace metal cancantrations prior to 1993 were reported as the total metals fraction. The CDPE9: atar~~^'+° are for the dissolved concentration. Consequently, trace metal values prior to 1993 era not directly comparable to the CDPHE atandar+d. Well HGDALI chemistry, in comparison to CDPHE's agriculture s*°^'+°~"+°, exoaedad the B limit Of 0.75 mq/1 three times between 1993 and 1995, the Mkt limit of 0.2 mq/1 four times between 1993 and 1995, and the 9e limit o£ 0.02 mq/1 once. 3averal constituents including H, Cd, t4i, and Pb had total concentrations in samples collected prior to 1993 which were greater than the CDPHE sr°^'+°^+, but a comparison between the atar~=+~'+ and the measured value may not be appropriate. CDPHE classifies ground water as "Agriculture Oae-Quality^ when the background . TDS value is lase than 10,000 mg/1. Well H®AL1 exceeded the CDPFIE TDS value of 10,000 for all 19 sampling events. FIDEQ guidelines for TDS era 5000 mg/1 and 2000 mg/1 for livestock watering and irrigation, respectively, while the SO. guideline oP 3000 mg/1 is for liveetorJr watering. Well HGDAi.l TDS and 30. concentrations also exceeded the WDEQ guidelines for all 19 sampling events. The comparison between CDPHE agricultural atan~:_^'+~ and WDEQ guidelines and concentrations reported in H®AL1 samples indicates that the water in well HGDALI is not suitable £or use ae either livestock drinking water or irrigation water. The major constituents rendering the water unsuitable era H, bfi, SO., and TDS. In addition, SAR levels ranged from 30-59 rhirh results in the rater receiving a "poor classification" rating for irrigation use, with the water posing an extm®e sodium hazard for the soil. Well HGDAL2 rhPmiatry, in coa~arison to CDPEO:'s agriculture standards exceeded the B limit of 0.75 mg/1 and the [M limit of 0.2 mg/1 for nll five sampling events batmen 1993 and 1995. Several constituents including H, Cd, tM, and Pb had total concentrations in samples collected prior to 1993 which wawa greater than the CDPHE ar°^.+..,~, but a comparison between the standard and the measured value may not be appropriate. Wall HCAAL2 exceeded the CDPHE TDS value of 10,000 mg/1 for all 17 sampling events. Zn addition, the TDS and SO. conc>3ntr4tions exceeded the WDEQ guidelines for all 17 sampling events. The comparison between COPFO: agricultural atarLa ~+•+° and FIDEQ guidelines and mncentrationa reported in H((~~AI.2 samples indicates that the water in roll HGDALl is not suitable for use as either livestock drinking water or irrigation rater. Tha major conatituanta *+°^'+°^ing the water unsuitable are H, FIIt, SO, and TDS. In addition, SAR levels ranged from 7-27 which results in the rater receiving a "fair classification" rating for irrigation use, rich the water posing a sodium hazard £or the soil. • RN-o~ 13 Revised 2/9B