Dames & Moore, 1999 - USDA Forest Service

Site. Samples collected for dissolved metals analysis were filtered in the field to remove sediment before
sample preservation. The results of laboratory analyses are presented in Section 5.3.
3.2.3 Storm Event Sampling
The MayIJune 1997 work plan called for sampling a post melt season storm event to observe the effects
of rainfall infiltration on water quality of seepage flow and baseflow into Railroad Creek from the mine
workings. The sampling guidelines stipulated that storm event sampling at selected seep, portal and creek
locations would be triggered after 0.5 inches of rainfall fell within 24 hours, and after a period of dry
weather had occurred that was sufficient to result in observed build-up of metal salts on the surface of the
tailings piles. In lieu of the occurrence of these climatic conditions, weekly sampling of selected seep.
portal and creek stations would be completed during the MayIJune 1997 sampling round:
During the MayIJune 1997 sampling period, the climatic conditions which would have triggered a storm
event sampling round were not observed. Consequently, the weekly sampling was undertaken. Referring
to Figures 3.2-1 and 3.2-2, and Table 3.2-2, weekly sampling stations included the portal drainage at P-5.
Railroad .Creek stations RC-6 and RC-2 (upstream and downstream of the mine), and seeps SP-23
(upstream of the tailings), SP-I5E (related to the mill site and maintenance yard), and SP-2 (downstream
of the tailings). The weekly sampling rounds provided a more comprehensive time series comparison
between water quality and flow conditions in the portal, selected seeps and Railroad Creek than would
have been available if only one round of sampling were conducted during the MayIJune sampling event.
The samples were analyzed for the primary analyte list of metals (aluminum, barium, beryllium,
cadmium, calcium, chromium, copper, iron, lead, magnesium, manganese, nickel, potassium, silver,
sodium, and zinc), alkalinity, sulfate, total dissolved solids, total suspended solids, and hardness. The
results of the laboratory analyses are presented in Section 5.3.
3.2.4 Geomorpbologic Survey
As part of the streamflow survey and habitat evaluation, geomorphologic observations and channel
geometry surveys were completed at each of the streamflow stations in Railroad Creek. Additional
channel data were also collected at the aquatic habitat sampling stations (see Section 3.9). Aerial
photographs and historic data on Railroad Creek were also reviewed to supplement the evaluation of the
channel data.
The purpose of the survey was to provide sufficient data to characterize the erosion and sediment
transport potential of Railroad Creek, provide baseline channel habitat data, and to characterize the nature
of the streambed adjacent to the tailings piles where the build-up of an iron cemented layer, or ferricrete,
has been documented.
Referring to Figures 3.2-1 and 3.2-2, an initial channel geomorphology survey was completed by
observing the Railroad Creek bed beginning upstream of RC-6 to the mouth (at Lucerne). The survey
included a characterization of bed'material, channel slope, water quality (pH, specific conductance and
temperature), bank conditions, riparian conditions, and mapping of areas of erosion and deposition. The
data collection during this survey was designed to characterize overall channel conditions within surveyed
reaches and was qualitative in nature. The results of the survey are presented in Section 4.3:3.3.
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17693-005-019Uuly 19, 1999;2:07 PM:DRAFT FlNAL RI REPORT