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(overburden or Dakota coal) monitor wells completed in the northwest portion of the New Horizon <br />1 permit area. Consequently, Monitor Wells GW-N8 and GW-N9 have been incorporated and used <br />in both the overburden and Dakota coal potentiometric surface maps (Maps 2.04.7-2 and 2.04.7-3). <br />Potentiometric Surfaces <br />Potentiometric surface maps for the overburden, Dakota coal and underburden aquifers are <br />presented in Maps 2.04.7-2 and 2.04.7-3, respectively. <br />Overburden. The potentiometric surface map of the overburden is presented on Map 2.04.7-2. <br />The water level contours were constructed based on the static water level measurements made in <br />September, 1987 from five overburden monitor wells and two multiple completion (overburden and <br />Dakota coal) monitor wells. It was necessary to include the two multiple completion monitor wells <br />(GW-N8 and GW-N9) in the overburden potentiometric map because they are the only monitor <br />wells located in the northwest portion of the permit area. The overburden generally has the <br />shallowest static water level of the bedrock aquifers that are monitored within the study area, so <br />the multiple completion monitor wells should be representative of the overburden aquifer water <br />• levels. <br />Ground water in the overburden aquifer is generally unconfining to only slightly confining. The flow <br />in the overburden is generally from the northeast to the southwest and is topographically controlled. <br />Potentiometric contours indicate that there is discharge of ground water along Tuttle and Calamity <br />Draws. The ridge that separates the two draws is a ground water divide, causing the ground water <br />to flow from the ridge top toward both Tuttle and Calamity Draws. The primary recharge area is <br />from the northeast and from vertical leakage from the irrigation dilches and flood irrigation. The <br />average water level gradient in the overburden is .0342 ft/ft with a range between .0333 ft/ft and <br />.0375 ft/ft. <br />Dakota Coal. The potentiometric surface map of the Dakota coal is presented on Map 2.04.7-3. <br />The water level contours were constructed based on the static water level measurements collected <br />in September, 1987 from seven Dakota coal monitor wells and two multiple completion <br />(overburden and Dakota coal) monitor wells. It was necessary to include the two multiple <br />completion monitor wells (GW-N8 and GW-N9) in the Dakota coal potentiometric contour map <br />• Revisetl 18 Aug 2003 2.04.7-6 <br />