2021-09-03_PERMIT FILE - C1981019A (8)

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RULE 2 PERMITS Little Collom Gulch — Little Collom Gulch was dry for all attempted monthly sampling events. Little Collom Gulch can be considered ephemeral at sampling point LLCG. Jubb Creek — Jubb Creek, at monitoring point CJC at the confluence of the East and West Forks, produced a maximum flow of 0.25 cfs in February 2005, and declined to 0.01 cfs in October and November, before freezing in December through January, and going dry in February 2006. The West Fork of Jubb Creek (monitoring point WFJC) produced flow from May through August, peaking in June at 0.30 cfs, and remaining dry throughout late summer, fall, and winter. Based on the available monitoring data, both streams can be characterized as intermittent, with spring high flows apparently the result of snowmelt. The East Fork of Jubb Creek was dry for all attempted monthly sampling events throughout the monitoring period, and can be characterized as ephemeral. Hydrographs for Jubb Creek sample locations can be found in Figures 2.04.7-42 and 2.04.7-43. From the hydrographs, it can also be seen that water quality, as represented by Total Dissolved Solids (TDS), varies seasonally in response to dilution from spring runoff. Springs and Seeks — A total of 33 seeps and springs fall within the Collom, Little Collom, or Jubb Creek drainages that will be affected by the mining. Springs and seeps were monitored semi-annually, except when prevented by dry or frozen conditions. Those springs and seeps are identified in Table 2.04.7-47, and monitoring results are summarized in Table 2.04.7-49. Spring and seep monitoring locations are depicted on Map 10B. The monitoring data illustrates that springs individually contribute up to 0.30 cfs to stream flows during spring runoff, but often run dry or contribute far less than 0.01 cfs during summer and fall baseflow periods. Numerous springs identified during vegetation surveys proved to be dry during subsequent attempts to sample them. Based on the maximum values of sampled spring/seep flows, springs and seeps may contribute an aggregate maximum of approximately 0.75 cfs to surface flows to Collom Gulch. In Jubb Creek, they may contribute up to 0.17 cfs. In Little Collom Gulch, springs and seeps may contribute up to 0.32 cfs, but that discharge is apparently absorbed into valley fill or retained in stock ponds at some point upstream of streamflow sampling location LLCG, which was dry during all sampling attempts. Minimum (summer/fall) spring/seep flow contributions ranged from 0.02 cfs to 0.07 cfs for the watersheds in question. Surface Water Quality — Surface water and spring/seep samples were collected from December 2004 through May 2006 and March of 2012 through April of 2015in the Collom Gulch, Little Collom Gulch, and Jubb Creek drainages. The Colorado Mined Land Reclamation Division's (CMLRD) Guidelines for the Collection of Baseline Water Quality Data were utilized during the baseline monitoring. Water quality sampling and laboratory analyses were conducted in accordance with Rule 2.03.3(4) for analytes defined in Rule 2.04.7(2), and for analytes also listed in the CMLRD Guidelines for the Collection of Baseline Water Quality and Overburden Geochemistry. Field measurements for pH, electrical conductivity, temperature, dissolved oxygen, and flow were taken monthly or semi-annually at stream sampling locations, and semi-annually at springs and seeps, unless prevented by freezing or lack of surface flow. A sample was analyzed for the full suite of recommended water quality constituents monthly at each Collom Gulch stream sampling location and semi-annually at Jubb Creek and the West Fork of Jubb Creek, except when no flow was present. No water quality samples were taken at Little Collom Gulch or the East Fork of Jubb Creek, which were dry during all sampling events. The seeps and springs were monitored for field parameters semi-annually. A single full -suite sample was collected at each location in June or September 2005, and in a few cases April 2006. Baseline surface water quality monitoring data are presented in Tables 2.04.7-46 through 2.04.7-49. These tables include those constituents identified in Rule 2.04.7(2)(b)(11), except for acidity and dissolved iron, which were not analyzed. Values presented for iron and manganese represent total recoverable concentrations. Hydrographs are presented in figures 2.04.7-40 to 2.04.7-43, with total dissolved solids (TDS) included to show seasonal variability with respect to stream flows. The trilinear diagrams in Collom — Rule 2, Page 34 Revision Date: 4/7/17 Revision No.: RN -07