Dames & Moore, 1999 - USDA Forest Service

curve developed for RC-4 was used to estimate flows from the continuous water level recorder (known as
a "Troll") to create a continuous hydrograph for this station. The rating curve data was also used to
estimate concurrent flows at all stations enabling direct flow comparisons and relationships between
stations to be developed.
All of the discharge measurements that were made at RC-2 and RC-4 were used to develop the ratings.
unless a concurrent stage measurement was not available. Additionally, flow measurements that deviated
by more than 20 percent from the average rating curve were excluded from the rating because these
measurements were assumed to represent either unacceptable measurement error or a changed condition
which did not persist in the remainder of the data base.
Three flow measurements were excluded based on this criteria, including the June 16. 1997, measurement
at RC-4, and the July 10, 1997, measurement at RC-2 collected by Dames & Moore and the July 25,
1996, measurement at RC-2 collected by the USFS; additional discussion regarding the excluded flow
measurements and their significance is presented in Section 4.3. The other findings of the streamflow
surveys are also presented in Section 4.3.
3.2.2 Water Quality Sampling
Referring to Figure 3.2- 1 and 3.2-2, Table 3.0- 1 under "Surface Water," and Tables 3.2- 1 through 3.2-5,
surface water samples were collected from Railroad Creek during the four sampling events in 1997 and
one event in May 1998, from Copper Creek at stations CC-I (south and upstream of the tailings piles),
CC-2 (near the confluence with Railroad Creek) during four sampling events, and from CC-Dl (the
Copper Creek diversion) during the five sampling events. Samples were also collected during four
sampling rounds from two stations in the 1500-level main mine portal drainage, P-l and P-5.
Miscellaneous surface water samples were collected in select Railroad Creek tributaries and at all aquatic
habitat sampling locations (except RC-9).
Surface water quality samples were collected using a Teflon depth integrated sampler, which collects
samples of the complete water column. .The sampler was slowly lowered to the bottom of the stream
allowing a constant inflow rate through the water column. The samples were also composited across the
width of the stream by sampling at evenly spaced locations across the channel, and combining these
discrete samples into one composite for the station. The depth integrated sampler could only be used
when the water depth was greater than approximately one foot, and consequently could not be used to
sample the portal drainage. For comparative purposes, discrete depth integrated samples were also
collected (in addition to the width composite sample) at south bank locations at stations RC-I, RC-4 and
RC-2.
The surface water samples were tested in the field for pH, specific conductance, temperature, dissolved
oxygen, and redox potential. Laboratory analyses included total and dissolved metals (aluminum, arsenic,
barium, beryllium, cadmium, calcium, chromium, copper, iron, lead, magnesium, manganese, mercury,
molybdenum, nickel, potassium, selenium, silver, sodium, thallium, uranium, and zinc), ortholtotai'
phosphorous, cyanide, total dissolved solids, total suspended solids, chloride, nitrite-nitrate, sulfate,
silicates, alkalinity, color, and hardness as specified in the SAP and QAPP. Tailings pile 1 was reportedly
used historically as a dump area for Howe Sound Company and Holden Village; thus, TPH and PCBs
were analyzed at selected locations upsmam (RC-6), adjacent to (RC-2) and downstream (RC-3) of the
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17693-005019Uuly 19. 1999;2:07 PM;DRAFT FINAL RI REPORT