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TABLE 7-2 Estimate of Aquifer Unit Properties within SHPGWMD Aquifer System
<br />Column 1
<br />Column 2 Column 3 Column 4 Column 5 Column 6 Column 7 Column 8 Column 9
<br />Column 10
<br />Economically
<br />Aquifer Unit
<br />Aquifer Unit Volume, Aquifer Unit Aquifer Unit Area, Avg. Saturated Percent Specific Saturated Volume, Percent
<br />Ft .3 Volume, Ac -Ft Ft .2 Thickness, ft. Sand/Silt Yield acre-feet Recoverable
<br />Recoverable (acre -
<br />feet)
<br />Ogallala#1
<br />427,000,000,000 9,802,571 13,451,188,403 32 0.8 0.2 1,568,411 30%
<br />470,523
<br />Ogallala#2
<br />50,700,000,000 1,163,912 3,272,482,404 15 0.8 0.2 186,226 20%
<br />37,245
<br />Ogallala#3
<br />30,500,000,000 700,184 2,624,815,683 12 0.81 0.2 112,029 15%
<br />16,804
<br />Ogallala#4
<br />18,400,000,000 422,406 1,606,800,626 11 0.81 0.2 67,585 15%
<br />10,138
<br />Ogallala#5
<br />318,000,000,000 7,300,275 3,359,123,416 95 0.81 0.2 1,168,044 40%
<br />467,218
<br />Ogallala Subtotal
<br />844,600,000,000 19,389,348 24,314,410,532 35 0.8 0.2 3,102,296
<br />1,001,928
<br />Dakota North
<br />75,600,000,000 1,735,537 1,539,506,897 49 0.5 0.15 130,165 35%
<br />52,066
<br />Dakota Middle
<br />407,000,000,000 9,343,434 8,349,172,007 49 0.5 0.15 700,758 35%
<br />280,303
<br />Dakota South
<br />1,690,000,000,000 38,797,062 32,077,955,509 53 0.5 0.15 2,909,780 35%
<br />1,163,912
<br />Dakota Subtotal
<br />2,172,600,000,000 49,876,033 41,966,634,413 52 0.5 0.15 3,740,702 35%
<br />1,496,281
<br />Cheyenne
<br />5,030,000,000,000 115,472,911 51,512,640,646 98 0.5 0.15 8,660,468 40%
<br />3,464,187
<br />Dakota Aquifer Total
<br />4,960,468
<br />Dockum
<br />Proven (200 feet)
<br />7,460,000,000,000 171,258,035 42,412,037,162 176 0.5 0.15 12,844,353 50%
<br />6,422,176
<br />Possible (beyond 200 ft.)
<br />11,190,000,000,000 256,887,052 63,618,055,743 300 0.5 0.15 19,266,529 50%
<br />9,633,264
<br />Total Proven Reserve
<br />12,384,573
<br />Total Reserves
<br />22,017,837
<br />Column Explanation:
<br />1. The aquifer units within the Southern High Plains Designated Ground Water Basin
<br />2. The volume of saturated thickness is based upon a computer calculation of the difference between the water surface elevation and the bottom of the formation, if the
<br />unit was under water table conditions, or the difference between the top and bottom of a confined aquifer.
<br />3. The volume, in acre-feet is determined by dividing the volume in cubic feet by 43,560 sq. ft to convert to acre-feet.
<br />4. The area of the unit is determined using computer calculations of the boundary of the unit as determined from the map of the unit.
<br />5. The average saturated thickness is determined by dividing the volume, column 2 by the area, column 4.
<br />6. The percent sand and silt is based upon the Phase 1 study.
<br />7. The specific yield is based upon the Phase 1 study.
<br />8. The saturated volume is determined by multiplying the volume in acre-feet, column 3 by the percent sand/silt, column 6 times the specific yield, column 7.
<br />9. The percent of recoverable is an indicator of the percent of water that would be sufficient for economical use by large capacity wells.
<br />10. The economically recoverable volume of water is based upon 50 percent of the saturated volume, unless the average saturated thickness is less than 100 feet. If the
<br />saturated thickness is less than 100 feet, the percentage is reduced proportionally (column 9) to reflect the impact upon large capacity wells production.
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