Silver Creek - Division of Water Quality - Utah.gov

Silver Creek Watershed TMDL Final Report
Data for Normal Precipitation and Normal Potential Evapotranspiration were obtained for these
three stations. Table 1 shows the area of influence for each of the weather stations, based on
linear partitioning.
Table 1: Weather Station Areas of Influence
Station Area (ac)
Percent of
Watershed
Brighton 100 0.3%
Park City 13,778 45.4%
Wanship 16,443 54.2%
Total 30,321 100 %
Using these areas, monthly composite values for Normal Precipitation and Normal Potential
Evapotranspiration were calculated. These values are shown in Table 2.
Table 2: Composite Watershed Weather Data
Jan Feb Mar Apr May Jun Jul
Total
Aug Sep Oct Nov Dec (in)
Total
(AFY)
Total Precip (in) 1.56 1.25 1.52 1.63 1.63 1.13 1.66 1.33 1.91 1.45 1.78 1.71 18.55 47,000
Potential ET (in) 0.76 1.13 2.07 3.53 5.23 6.59 7.56 6.57 4.43 2.68 1.15 0.71 42.41 107,000
It is noteworthy to mention the relatively high value of Normal Annual Potential
Evapotranspiration (shown in acre-feet per year), which is more than two times the Normal
Annual Precipitation in the watershed. While this value does not represent true evaporation, it
does reflect the dry climate of the watershed and the high potential for evaporation losses.
Flow Data
Flow data for each of the STORET sampling locations were typically recorded as water quality
samples were taken. A hydrologic profile showing how average annual flow increases from the
top of the watershed to the outlet is shown in Figure 3.
Figure 4 shows seasonal trends in flow for each of the key stations for each bimonthly period.
Peak flows occur at Wanship in the second bimonthly period (March to April), while the other
locations have their peak flow during the third bimonthly period (May to June).
The key stations included in the flow analysis and water quality analysis are listed in Table 3.
Table 3: Key Stations
Key Station Description
Park City 492695
Richardson Flat 492685
Above Atkinson 492680
Silver Creek WRF 492679
Atkinson 492674
STORET Number
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