2006-06-02_PERMIT FILE - C1980007A (5)

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and precipitation Recovered data are defined as data that have passed quality accnranee and review as being valid reportable data. The following information s„mmari~PC the recovered and reported data as percentages of total possible data quantities for the period of this report Any missing data were primarily due to instrtmtent malfunctions. Parameter Site 1 Percent Recove Site 2 Site 3 R'"md S 70.77 52.97 79.12 Wmd Direction 70.49 52.97 79.33 Ambient Air T 68.75 51.65 7525 Relative Hmni ~ - 43.93 - Prec' nation - 53.12 - Wind Data collected during the spring and summer quarters of 1977 indicate w=inds varied at the three sites. Minimum wind speeds ranged from 0.6 mph to 1.4 mph. Maximum wind speeds ranged from 12.4 mpg to 19.7 mph Mean wind speeds at the three sites were between 5.9 mph and 8.3 mph. Hourly wind speed data show a consistent daily pattern that is almost identical for Sites 1 and 2. The wind speed typically increases during the nighttime horns from about 7:00 p.m. Mountain Standard Time (MST), reaching a peak speed of about 10.5 mph at about 7:00 am. the next morning. At this time, the average wind speed drops over two or three horns to reach a mornin • minimum speed of about 6.0 mph. It then rapidly increases to a second maximum of about 9.5 mph by noon, with a subsegtrerrt slow decrease to reach a late afternoon minimum of about 5.0 mph The average diurnal variation in wind speed at Site 3 is strikingly different from that at Sites 1 and 2. At Site 3, wind speed rr,nainc relatively calm throughout the nighttime hours. Starting at about 8:00 a.m, wind speed increases to about 8.0 mph by 11;00 a.m It stays at this level until about 3:00 p.m. when it begins to decrease to its relatively constant nighttime level. Although the general shape of the diurnal wind speed curve at Site 3 is markedly different from those for Sites 1 and 2, there is a slight hint of an early morning (6:00 a.m) relative maximum and a morning (8:00 a.m.) relative minimum However, this behavior is much less predominant than at Sites 1 and 2. The explanation of this variation lies with the existence of a well established drainage flow down the canyon from east to west A relatively large basin to the east of the area (headwaters of the ly'orth Fork of the Gunnison River) provides the volrmre of air to support this re]atively intense flow which is fimneled through the narrow canyon past the West Elk Mine site monitoring network. This drainage flow is almost directly opposed to the geotropic or gradient flow which is typically from the southwest. At sunrise, atmospheric heating reduces the horizontal pressure gradient which supports the drainage flow. The wind speed at Sites 1 and 2 drops to relative minimum within several hours under this influence. Above this low altitude, high speed drainage layer, the winds at Site 3 remain relatively calm throughout the night and well into the rooming hours. As discussed later these relatively calm winds are less intense drainage winds themselves. The pronounced rise in the average wind speed at all sites during the late morning hours is primarily due to the breakup of the surface-based inversion, or stable air, within the valley. As the 1.0720 7/947805; 8947R7r; 695 PR06;Afmch 1006 PRIO