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Permit C-81-071 1996 Annual Hydrology Report <br />watershed area adjacent to (northeast of) Eckman Park. Site 800 is located a short distance <br />downstream from Eckman Park below the confluence of the Pond A discharge and site 14 and <br />flows at this station are monitored by the USGS (Station 09243800). Site 8 is located a short <br />distance downstream of the Foidel Creek mine portal area below Mine 1. And lastly, site 900 is <br />located further downstream above the confluence with Middle Creek. Flows at site 900 are also <br />are monitored by the USGS (Station 09243900). During 1996, all four Foidel Creek surface <br />water monitoring sites required monthly flow and field parameter measurements with quarterly <br />water quality sample collection. The monitoring requirements are further described to require <br />12 flow and field parameter monitoring instances to occur between March and September along <br />with 4 water quality sampling events. One additional site on Foidel Creek, site 304, required <br />water level monitoring on a monthly basis in conjunction with alluvial well 008-AV-2. All <br />required monitoring instances were completed during 1996. <br />Tables 18 through 22 provide summaries of the 1996 Water Year data collected at each site. <br />Tables 18a through 21a provide period of record statistical summaries of collected data at <br />specified sites. Table 22a provides a water level summary for site 304. Figures 32 through 47 <br />provide graphical representations of flow rates and selected water quality parameters recorded <br />at each site. Typical flow patterns were exhibited at these sites with spring runoff periods <br />accounting for the peak flows observed. Runoff magnitudes were higher than average during <br />1996 based upon comparison with previous years data. At all of these sites, the inverse <br />relationship between flow and field conductivity is evident. Anew minimum lab conductivity <br />value was recorded at site 14 in April with all other values occurring within previously <br />established ranges. Water quality parameter analyses conducted at site 800 during the year <br />returned values within previously established ranges with the exceptions of a new maximum <br />• bicarbonate and total alkalinity values and a new minimum SAR figure reported in June, and a <br />new maximum field conductivity noted in August. Analyses results outside of previously <br />established ranges for site 8 include new maximum total recoverable iron and lab conductivity <br />values noted in April, new maximum total recoverable mercury and total alkalinity values <br />recorded in June, and new minimum SARs documented in June and August. Site 900 recorded <br />new historical minimum values for lab conductivity and TDS in April. New maximum <br />magnesium, hardness, and TDS values were subsequently noted in September. <br />The base level of field conductivity measured during the fall, was higher in the downstream <br />sites on Foidel Creek. It measured approximately 900 umhos/cm in the upstream site (14) and <br />from 3200 to 3700 umhos/cm in the downstream sites 8 and 800 respectively Since <br />approximately 1981, the base level for conductivity at both downstream sites has been <br />increasing although there appears to have been a leveling off since approximately 1989. The <br />upstream site also reflects a notable conductivity increase in 1986, presumably as a result of <br />lower runoff flows since that time. During the second half of the 1996 irrigation season, the field <br />conductivities at Station 14 could not be measured as there was no measurable flow. <br />The difference between the conductivities at the upstream and downstream stations is <br />attributable primarily to spoil spring discharges related to surface mining. These discharges <br />cause increased concentrations of dissolved solids, calcium, magnesium, and sulfate and a <br />reduction in SAR in Foidel Creek. However, the increase in TDS levels during irrigation season <br />is not sufficient to cause material damage. While the spoil springs are adding some <br />manganese to Foidel Creek, the level at Station 8 is still below the total recoverable standard of <br />1000 ug/I for Foidel Creek. Historically, high total recoverable manganese also has been <br />• recorded in the upstream station (14), indicating that these values may in some instances be <br />attributable to non-mining related causes. <br />I IDOCUMENTNHR\ECKMAN\EP96TEXT.DOC 03/28/97 Page 6 <br />