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water within the lower Dakota Sandstone. This confined aquifer is recharged along the
<br /> Uncompahgre Plateau to the northeast and discharges towards the southwest. Transmissivity was
<br /> measured at six sites and varies from 3.0 to 88 ft2/day, averaging 38 ft2/day. Hydraulic
<br /> conductivity values varied from 0.07 to 4.5 ft/day, averaging 1.6 ft/day. This aquifer is not used
<br /> locally to any great extent.
<br /> The water in the underburden is characterized as hard, moderately alkaline saline water with high
<br /> sulfate concentrations (average sulfate concentrations of 695 mg/1). Two wells show a
<br /> calcium/magnesium sulfate type water while one well shows an alkaline sodium bicarbonate type
<br /> water. The TDS varies from 960-2648 mg/l, averaging 1619 mg/l. Dissolved iron levels vary
<br /> from 0.02 to 2.51 mg/l and average 0.63 mg/l. The sodium bicarbonate well occasionally exhibits
<br /> pH levels that exceed the recommended agricultural standard. Another well shows manganese
<br /> levels that exceed the agricultural standards. All wells meet the recommended water quality
<br /> standards for livestock watering. The underburden aquifer does not produce acceptable water for
<br /> domestic purposes; TDS, sulfate and ammonia standards are exceeded. Measurable trace element
<br /> concentrations in the underburden aquifer include aluminum, arsenic, boron, cadmium, copper,
<br /> fluoride, iron, lithium, manganese, mercury, nitrate, vanadium and zinc.
<br /> Ground water within 150 feet of the ground surface has been only minimally developed for use in
<br /> the Nucla area. High salinities and occasionally high sodium or sulfate concentrations preclude
<br /> its use as domestic, agricultural or stock water. In addition, moderate hydraulic conductivities are
<br /> coupled with low sustained well yields (less than 1.5 gpm), discouraging sustained dependence on
<br /> wells completed within these aquifers.
<br /> E. Soils
<br /> There were three major soils types in the original 220-acre NHM area: Progresso-Bond Complex,
<br /> 2 to 15 percent slopes; Barx — Barx, scalped — Barx, buried complex, 1 to 4 percent slopes; and
<br /> Lithic-Typic Haplaquolls, 1 to 3 percent slope. The Progresso-Bond complex is comprised of 40
<br /> percent Progresso, 40 percent Bond, 10 percent Barx (see below), 5 percent Travesilla, and 5
<br /> percent Bowdish series soils. The Progresso series is classified as a fine-loamy, mixed, mesic,
<br /> Ustollic Haplargid. The Bond series is a loamy, mixed, mesic Lithic Ustollic Haplargid. The main
<br /> difference between these two is the distance to bedrock; Bond soils are shallow (17 to 19 inches
<br /> to bedrock)while Progresso soils are fairly deep (36 inches to bedrock). Barx soil is found in the
<br /> southeast corner, primarily within Mapping Unit D70B. It is classified as a fine-loamy, mixed,
<br /> mesic Ustollic Haplargid. It is a deep, well-drained sandy loam formed in sandstone derived
<br /> alluvium.
<br /> The ephemeral drainages contained three families of Haplaquoll soils: Lithic, Lithic/Typic, and
<br /> Typic Haplaquolls. The loamy, mixed, mesic, Lithic Haplaquolls are found in the upper reaches
<br /> of the swales in the area and are the shallowest of the three series (bedrock at 11 inches).
<br /> Lithic/Typic Haplaquolls (coarse-loamy, mixed, mesic, moderately deep Typic Haplaquolls) are
<br /> found in the mid to lower reaches of the swales and exhibit good quality soil to a depth of about
<br /> 24 inches. The fine-loamy, mixed, mesic, deep Typic Haplaquolls are found in the lower reaches
<br /> of the swales and along Calamity Draw. These soils have sandy loam and loam textures to a depth
<br /> of about four feet with sandy clay loam below that. The soils were classified as Haplaquolls
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