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ADMINISTRATIVE CRITERIA

      Criteria are developed to serve as agency guidelines on how to process and evaluate pending applications for groundwater appropri ations. To quantify well impacts for this process, a two- dimensional finite difference groundwater flow model (Morrison, 1989) will be used to simulate the effects of pumping on water levels due to existing and proposed wells. A two-dimensional solute transport model has been developed to estimate changes in TDS due to existing wells and may be used if necessary to estimate impacts due to proposed wells. Administrative criteria are as follows:

      1.    The Alamogordo-Tularosa administrative area will be administered using blocks one-half mile square using the grid utilized by the groundwater model (Figure 3). If a proposed well field location is within more than one block, calculations should be performed with the well field located in the block which provides the most conservative analysis with respect to protecting existing water rights.

      2.    Water level declines and TDS changes due to existing wells will be considered along with water level declines due to a proposed well. TDS changes due to the use of proposed wells may also be considered if it is deemed necessary. Impacts will be computed to the beginning of 2022 for existing and proposed wells, and to provide a conservative analysis to protect existing water rights, the assumption will be that the proposed well would start pumping January of 1982.

      3.    It is assumed that a reasonable estimate of future water use will be between the amounts estimated for the medium and high water use projections presented in Morrison ground water flow model. Impacts are assumed to be proportional to water use. Water level declines and changes in TDS will be computed by taking 20 percent of the absolute difference between the medium and high scenario results and adding the resultant to the medium scenario estimates. IMPACTS = Medium + 0.20(High - Medium)

      4.    The average annual water level decline rate due to existing uses will be calculated for each block by dividing the impacts computed in item 3 and dividing by 40 years. In an administrative block in which the average annual water level decline exceeds 2.50 feet, that block will be termed "critical." No new groundwater appropriation will be granted in a "critical" block, except as provided for in item 9.

      5.    In an administrative block where the 1980s freshwater thickness is less than 400 feet and the calculated average annual water level decline rate exceeds the value FW/4t

where, FW = estimated freshwater thickness (ft.) in the block in the 1980s
              t = 40 years

      6.    A groundwater appropriation will not be granted if it will cause the calculated average annual water level decline rate due to existing and proposed uses to exceed 2.50 feet, or the value determined in item 5 whichever is less, except to the extent as provided for in item 9.

      7.    For blocks containing freshwater in the 1980s, the estimated increase in TDS due to the use of existing water rights will be estimated using the procedure in item 3 and will be added to the estimated TDS for each block using data compiled in Appendix I of the groundwater flow model documentation (Morrison, 1989). Any freshwater block which has a resultant TDS of 1,000 mg/l or greater at the beginning of 2022 will be termed "critical." No new groundwater appropriations will be granted in a "critical" block, except as provided for in item 9.

      8.    For blocks which did not contain freshwater in the 1980s, increases in TDS due to existing and proposed wells will be considered on a case-by-case basis.

      9.   A groundwater appropriation may be granted provided that the proposed appropriation will not produce an average annual decline rate of greater than 0.05 feet on any "critical" block. Calculated water level declines for each new appropriation will be accounted to the nearest 0.01 foot. Applications to appropriate underground waters in accordance with Section 72-12-1 of the New Mexico Statutes will be granted within critical blocks with conditions of approval as deemed necessary to protect existing water rights.

      10.    Wells may not be completed to a depth of more than 50 percent of the freshwater thickness of the 1980s. Freshwater thickness may be obtained from Figure 4, or from site specific data.

      11.    Local effects due to a proposed appropriation will be evaluated on a case-by-case basis to ensure that impacts on the nearest wells of other ownership are not unreasonable. Available water columns, impacts from existing and proposed uses, and the ability to deepen wells to sustain a freshwater supply will be considered as deemed necessary. Calculations shall be performed in a manner to maximize the estimated impact to existing wells. For existing wells located 500 feet or less from a proposed well, drawdown calculations may be performed using the method presented by Prickett and Lonnquist, 1971 (page 61); or by using the Theis equation. Aquifer parameters used for local effect determinations may be obtained from the groundwater flow model or from site specific information as deemed reasonable. For existing wells located more than 500 feet from a proposed well, the groundwater flow model or any other method as deemed reasonable may be used to evaluate impacts to the nearest wells.

      12.    For the purpose of determining the annual water level decline due to existing rights, when a permit is granted for a new groundwater appropriation, the computed average annual water level declines from the approved permit over a 40-year period will be added to the declines computed in item 4. The well to be drilled under an approved permit becomes an existing well in considering subsequent applications.

      13.    For modeling purposes only, a groundwater appropriation for irrigation purposes will be assumed to require a diversion requirement of 4.17 acre-feet per acre per annum. This is an estimated maximum diversion rate for irrigation in the basin based on an average consumptive irrigation requirement of 2.50 acre-feet per acre and an on farm irrigation efficiency of 0.60 (Wilson, 1993). Other diversion requirements, consumptive irrigation requirements, and irrigation efficiencies may be used as deemed reasonable (i.e. other information supplied by applicant may be considered). For the purpose of calculating conservative drawdown effects due to the use of new irrigation wells, it will be assumed that irrigation wells withdraw and deplete the total diversion requirement. For groundwater appropriations other than irrigation purposes groundwater depletions will be assumed to be equal to the diversion rate unless return flow credit has been approved by the State Engineer. Applications requesting return flow credit will not be granted unless the timing and quantification of flows back to the aquifer have been demonstrated.

      14.    As per item 13 above, a groundwater appropriation for irrigation purposes will be assumed to require a maximum diversion of 4.17 acre-feet per acre per annum. Requests to increase the diversion above this amount (stacking of water rights) will be prohibited unless the request has been deemed necessary by the state engineer. Stacking of water rights, if deemed necessary, will only be approved after proper application is made, advertising has occurred, and the application has been deemed acceptable relative to the issues of impairment, conservation, and public welfare.

      15.    For applications to change point of diversion, or place or purpose of use; the maximum quantity of water continually consumptively used for beneficial use during the historical application shall be used as the amount which is available for consumptive use by the proposed transaction. For applications to transfer rights used for irrigation purposes, the average histori cal consumptive irrigation requirement will be maximum quantity available for transfer. If this transfer is to be applied for irrigation use, the diversion requirement will be established in accordance with criterion 13 above. If the transfer is from irrigation purposes to purposes other than irrigation, the diversion requirement for the move-to site will be the average historical consumptive irrigation requirement. Transfers within a critical block to the same block may be granted if other applicable criteria have been met.

      16.    Application for supplemental well(s) may be granted if applicable criteria have been met. Well(s) within a critical block may be supplemented by well(s) within the same block as allowed as follows: a) applications for supplemental well(s) for a declared water right may be approved, but only up to the amount historically beneficially used; b) application for supplemental well(s) for permitted water rights in good standing, may be approved for the total permitted water right.

      17.    The state engineer shall determine whether an application is contrary to the conservation of water in the state. Water conservation issues will be addressed on a case-by-case basis. Applications shall be reviewed to ensure the highest and best technology practically available will be utilized to ensure conservation of water to the maximum extent possible.

      18.    The state engineer shall determine whether an application is detrimental to the public welfare of the state. The state water planning process, statewide issues of concern, water quality issues, and information submitted by parties in a protested application, will be considered by the state engineer in making the public welfare determination.

      19.    Each application will be reviewed to determine whether the well may reasonably obtain the quantity of water sought. A determination of the availability of water from a particular point in the aquifer will be based on the transmissivity of the aquifer at that location, the proposed well casing diameter, the water column in the well and the freshwater thickness. In addition, it will be assumed that a well capacity of at least 6 gallons per minute will be required per irrigated acre and that an appropriation for other than irrigation purposes will be approved for a quantity not to exceed 60 percent of the well capacity, unless demonstrated by the applicant that a higher diversion percentage is appropriate.

      20.    As new data become available, or as conditions warrant, the above criteria and model may be revised by the state engineer to best achieve the administrative objectives.

APPROVED:	Thomas C. Turney		Date
	State Engineer

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