Laserfiche WebLink
r <br /> 5.5 BAROMETRIC PRESSURE <br /> Barometric pressure data was recorded at the 14`h Street Station in Modesto, California, the <br /> nearest barometric station to the site. As shown on Figure 4, barometric pressure remains fairly <br /> steady during the warmer months (late April through September) and increases dramatically <br /> during the fall and winter months. Barometric pressure is not monitored at the on-site MET <br /> station at the FSL. <br /> 5.6 AIR TEMPERATURE <br /> Over the three year monitoring period,the site exhibited an average daily temperature of <br /> approximately 59.5'F. For comparative purposes, the average air temperature measured at the <br /> Manteca Station over the same monitoring period was 59.4°F. The maximum temperature of <br /> 106°F was experienced on July 5, 2007, and the minimum temperature of 21.7°F was <br /> experienced on January 16, 2007. Figure 5 illustrates the temperature trends observed at the on- <br /> site weather station over the three year monitoring period. <br /> 5.7 WIND SPEED AND DIRECTION <br /> The average daily wind speed and direction observed and recorded at the on-site weather station <br /> during the three year monitoring period was approximately 5.0 mph from the west-northwest <br /> (Figure 6 and Figure 7). As shown therein, wind direction often shifted from the west-northwest <br /> to the east-southeast direction during the winter(October to February). Wind speeds measured <br /> at the Manteca Station averaged 4.68 mph from the west-northwest over the same three-year <br /> period. <br /> 6.0 MONITORING RESULTS <br /> Figures 8 and 9 illustrate soil moisture content, temperature and rainfall over time at each of the <br /> two monitoring stations (MET and SAT stations) over the three year moisture monitoring period. <br /> 6.1 GENERAL <br /> The most significant soil moisture pattern observed at each probe location is the rapid drying <br /> trend that develops soon after each wetting event. The more persistent drying trend creates a <br /> strong upward capillary gradient through the soil profile and indicates that even deep soil <br /> moisture is extracted from the soil by evapotranspiration during most of the year. In fact, only <br /> during periods of wetting during and shortly after rain events does the soil suction induce a <br /> downward gradient. This effect creates an environment where dramatic upward migration of <br /> water from the soil cover and waste exists over the majority of the three year monitoring period. <br /> 5 <br /> Geologic Associates <br />