2015-02-18_REPORT - C1981014 - Laserfiche WebLink

Home Browse Search

EFCI Southf field Mine — 2014 Annaal Hydrology Report February 12, 2014 The approved surface water monitoring schedule requires semi - annual creek sampling and is typically conducted during the second and fourth quarters at the five monitoring stations listed above. Field measurements and laboratory data for surface water stations are summarized in the following discussions. Stream flow measurements since 2000 are summarized and shown on Table 8. Field and laboratory data for 2014 are provided in Appendix B. Earlier stream flow data for all monitoring stations are documented in AHR's on file at the Division. Field and laboratory water quality data representing the reporting period, and all previous years, for the surface water monitoring stations on Newlin, Magpie, and Second Alkali Creeks are summarized in Tables 9, 10, 11, 12 and 13. Ongoing monitoring of surface flows for these three creeks provides for identification and evaluation of any ongoing changes in water quality and quantity that may result from mining and related activities. Monitoring data provided Appendix B indicate dry creek bed conditions prevailed at the approved monitoring points at Newlin Creek, Magpie Creek and Second Alkali Creek when monitoring was conducted in May and December. These conditions are consistent with those found in recent years during the same time periods. Both Magpie Creek and Second Alkali Creek were regularly dry, having very few documented flow events over the life of the mining operation. At the time of active mining operations Newlin Creek usually flowed steadily for up to several weeks during spring snowmelt. On only few occasions the creek flowed briefly in response to a heavy rain event. In recent years the typical springtime flows have generally ceased as observed by EFCI and documented in related AlMs. During 2013, and again in 2014, EFCI conducted supplemental monitoring to further assess and document hydrologic conditions at locations along Newlin Creek including the Florence Reservoir (above the Mountain Park), the Mountain Park road culvert, and the Thompson Ranch road crossing culvert. This monitoring was done periodically from April through August, usually following rain events, the results of which are summarized below. 4/11/14: No flow at Thompson road culvert and Mountain Park road culvert; dry creek beds. Traces of snow remain on upland slopes. 4/22/14: No flow at Thompson road culvert and Mountain Park road culvert; dry creek beds. Bypass pipe dry at Florence Reservoir; inlet pipe to Florence waterline approx. 25 to 30% capacity. 4/30/14: Dry creek bed. Florence Reservoir overflow pipe dry; inlet pipe to Florence water line flowing approx. 25% capacity. 5/13/14: No flow at Thompson road culvert or Mountain Park road culvert following light rain and 2" snow. No indication of previous flows in creek bed. 5/22/14: No flow at Thompson road culvert, and no indication of previous flows in creek bed. 5/30/14: No flow at Thompson road culvert following light showers, and no indication of previous flows in creek bed. 7/16/14: 5" deep flow of muddy water in bottom of Thompson road culvert. 7/17/14: No flow at Thompson road culvert, and no flow downstream at monitoring point NC -1; flow lasted less than 24 hours. Evidence of flow on banks indicated that water had flowed approx. 6" deep at NC -1. No flow at Mountain Park road culvert, dry creek bed indicating no overflow at Florence Reservoir. 8/4/14: No flow at Thompson road culvert following rain showers (on 8/1), muddy creek bed observed. 8/26/14: No flow at Thompson road culvert following rain showers, muddy creek bed observed. 2014 AHR roxtdoc Page 19