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In order to obtain specific baseline water level information at New Horizon 2 a total of 22 monitor <br />wells were drilled and completed. In June of 1986,16 monitorwells (GW-N13, GW-N14, GW-N15, <br />GW-N 16, GW-N 16P1, GW-N 17, GW-N 17P1, GW-N 18, GW-N 18P 1, GW-N 19, GW-N20, GW-N21, <br />GW-N22,GW-N23,GW-N24andGW-N25)wereinstalled. DuringAugustandSeptemberof1987, <br />six additional monitor wells were installed, (GW-N29, GW-N30, GW-N31, GW-N32, GW-N33 <br />and GW-N34). Measurements for static water levels began at these wells immediately after they <br />were completed and developed. All ofthewaterlevel data are presented in tabularand graphicform <br />inAppendixDofAttachment2.04.7-1 Hydrological Monitoring Plan. Five more wells(GW-N36,GW- <br />N37, GW-N38, GW-N39and GW-N40)were added in May 1993. The firstthreewells were drilled <br />in thenorth-eastcornerofthepermitarea. The last twowellsweredrilledalongtheCalamityDraw. <br />During November 1998, six (6) new ground water monitoring holes were installed to collect baseline <br />data. Three of these (GW-N41, GW-N42, and GW-N43) were located in an up dip area while the <br />other three (GW-N44, GW-N45 and GW-N46) were located in a down dip area of the revised permit <br />area. The three holes at each site will monitor overburden, coal zone, and underburden <br />respectively. Baseline data collected between October 1988 and September 1999 are given in <br />• Attachment 2.04.7-2. During March 1999, two underburden monitoring holes, GW-N13 and GW- <br />N19were plugged and abandoned. <br />Alluvial Water Levels. One alluvial monitor well (GW-N22) was installed at New Horizon 2 to <br />monitor the unconfined alluvial aquifer system along Calamity Draw. Static water level <br />measurements were taken at this site since July, 1986. There is approximately 23 feet of <br />unconsolidated material (alluvium) with an average saturated thickness of 15.24 feet at this site. <br />During the 1987 wateryearthe maximum seasonal water level fluctuation forthis monitorwell was <br />about 3.6 feet, ranging from 5.62 to 9.22 feet below ground surface. Shallowing occurs at this well <br />from April through Septemberwhen the irrigation ditches are flowing and irrigation ofthe local fields <br />is occurring. Water level fluctuations in this well are controlled by the perennial flow patterns ofthe <br />adjacent drainage (Calamity Draw) which returns much ofthe excess West Lateral irrigation water <br />to the San Miguel River located approximately two miles downstream from this site. Water level <br />responses to precipitation events are not discernible as the effects of recharge from the irrigation <br />ditches mask any water level fluctuations that may result from ground water recharge by <br />precipitation. Monitoring ofthis well was discontinued after New Horizon 2 Mine became operational. <br />• (REVISED6/28/01) 2.04.7-2 <br />