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o f\J IV (,il The Cooper and Jacob (1946) and Jacob and Lohman (1952) methods assume that a nonleaky confining layer is present. However, alluvium present above the Leadville Limestone in the vicinity of the Redstone 21-9 well and the Belden Formation present above the Leadville Limestone in the vicinity of the Wright no. 1 well functioned as recharge boundaries during the test by virtue of decreased outflow to them. Because of decreased springflow and seepage to Colorado River allu- vium, the river, too, might be considered a recharge boundary during the test. To be strictly applicable, the Hantush (1960) method assumes that all leakage is supplied by a confining layer of infinite areal extent. Neither the aliuvium nor the Belden Formation extends across the entire area affected by flow from the Redstone 21-9 well. Finally, the Cooper and Jacob (1946) method assumes constant discharge and variable draw- down. However, a flowing-well test involves constant drawdown and gradually declining discharge. Nevertheless, Lohman (1979, p. 27} considered the Cooper and Jacob (1946) method to be a valid corroborative check of the more appropriate Jacob and Lohman (1952) method. Discharge ofYampa Spring -- As mentioned earlier in the report, the discharge of the Yampa Spring is difficult to measure directly because of the complex plumbing system constructed around the spring. The spring issues from the Leadville Limestone through overlying alluvium. The spring can be diverted to the Glenwood Hot Springs Lodge and Pool or released to the Colorado River by manipulation of gates into a 60-ft-diameter spring caisson. In the normal operational mode, no. 1, about 790 ft from the production well, had the largest drawdown of all monitored alluvial wells. Well USBR no. 11 about 2,500 ft from the production well, had the smallest drawdown of the monitored alluvial wells. Well USBR no. 3, about 590 ft from the Redstone 21-9 well, was closer to the production well than USBR no. 1 but had a smaller drawdown. Drawdown and recovery in the alluvial wells were in phase with the production well only in USBR no. 1. Except for USBR no. 3, the monitored wells and springs clearly demonstrated a decreasing affect of the production well with increasing distance from it. The fluctuation of water-levels in USBR no. 3 is enigmatic until the stage record of the Colorado River at the test site is examined. The stage of the Colorado River decreased only 0.03 ft during the flow period of the test, but declined another 0.23 ft during the first 3.2 days of the recov- ery period (table 4). The-decrease in the water level in USBR no. 3 during the flow period was 0.15 ft, too large to be attributable to a 0.03 ft decrease in stage of the Colorado River. It probably was caused by flow from the Redstone 21-9 well. The water level in USBR no. 3 decreased another 0.14 ft after flow from the Redstone 21-9 well had ended. By then, the river stage was declining rapidly. USBR no. 3 is less than 500 ft from the river. At this distance, hydraulic connection with the river is likely. The declining stage of the river could have prevented recovery in USBR no. 3 and caused the additional water-level decrease in the well. Water-level fluctuations in USBR no. 11 were completely out of phase with flow from the Redstone 21-9 well. Water levels in USBR no. 11 remained constant while the Redstone 21-9 well was flowing and declined after flow stopped. This pattern indicates that USBR no. 11 was not af- fected by the Redstone 21-9 well but was affected by some other factor. Like USBR no. 3, USBR no. 11 is less than 500 ft from the Colorado River. In fact, it is located nearly at the rim onhe river's north bank. The water level in USBR no. 11 remained constant while the river stage was nearly constant and began declining only when the stage of the river began declining. A water-level recov- ering as soon as the flow phase ended, and recovered 0.65 ft by the end of the recovery-monitoring period. Water levels in the USBR no. 3 well decreased 0.29 ft from the start of the flow period to the end of the recovery period. Water levels in the USBR no. 11 well remained constant during the flow period. A-13 ;,: