2011-11-04_HYDROLOGY - M1977348 (4)

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Colorado Division of Reclamation Mining and Safety November 3, 2011 Mr. Eric Scott 2 103 -81640 • A line representing an approximate % -mile radius around the property boundary; • A line representing an approximate 1/2-mile radius around the CKD area; • the CKD disposal area outline; • , the CKD monitoring wells (MW -1, MW -2, MW -3 and MW-4); and • The approximate groundwater flow direction based on water levels measured in the site monitoring wells. Please note that the well locations are considered approximate. Details of the 76 well permit applications are presented on Table 1. As shown on Figure 1, a majority of the 76 potential wells are located upgradient of the CKD disposal area. The DWR database identifies that sixty (60) of these wells are permitted for domestic use, which can include irrigation of up to 1 acre of land and water supply of domestic animals or livestock. The remaining wells are permitted for commercial (1), irrigation (1), geothermal (1), stock (2), or household (9) use. Two (2) permit applications did not have a primary use listed. Different symbols are used on Figure 1 to show the potential wells by use. 4. "How are nearby wells, if present, constructed /screened? Is static water level data available? This information may be presented on the map previously referred to, or on a separate figure." Screened intervals are included for some of the potential wells in the DWR database but not for all. The reported screened intervals are highly variable and exhibit a large range in both length and depth. For example, the shallowest reported screen interval of the 76 potential wells is 20 to 40 feet below ground surface and the deepest well has a reported screened interval of 1,080 to 1,200 feet below ground surface. In general, a majority of the potential wells are screened somewhere within the depth interval between 100 and 500 feet below ground surface. The screened intervals that are provided in the DWR database for the 76 potential wells are presented on Figure 2 and in Table 1. Water level data is also available in the DWR database for some of the 76 potential wells. These water levels are presented on Figure 1 along with the screened intervals and are included in Table 1. Please note that some of these water level data seem unreasonable and could represent data entry errors. Also, it is likely that the water levels were measure shortly following well installation and may not represent static or current conditions. We trust the information provided herein satisfies your requests and is presented in a manner that is adequate for your review. If you have any questions, please do not hesitate to call the undersigned at (303) 980 -0540. Sincerely, GOLDER ASSOC! TES INC. icug4 Sara Harkins Ed Pottorff, P.G. Associate /Senior Hydrogeologist Geologist Attachments: Table 1: Permitted Wells Search Results Figure 1: Site Layout and Permitted Well Search Results Figure 2: Well Permits with Screened Interval and Static Water Level Data i110\ 81840101001addlinfoaquiferchar_ fn1- 03nov111addliofoaquiferchar03nov11 .docx � ®i t Golder # Associates