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KLE/NFELOER <br /> Bright People.Right Solutions. <br /> 2.5 SOIL MOISTURE MONITORING <br /> Soil moisture sensors were installed with the ET Test Pad at the request of RWQC13 staff; <br /> however, soil moisture is not a criterion for ET cover evaluation. Soil moisture data are shown <br /> on Chart 2. <br /> 2.6 HISTORICAL DISCUSSION <br /> The ET Test Pad was fitted with soil moisture sensors set at depths of 1, 2 and 3 feet below the <br /> ground surface. Soil moistures in 2006/2007 were low, a reflection of the recently constructed <br /> ET Final Cover. The variability in the shallowest probe was greatest, as it was influenced most <br /> heavily by the cycles of wetting and drying caused by alternating periods of precipitation and <br /> sun. The response of the shallow probe to rainfall (1.6 inches in December) showed an increase <br /> iin soil moisture. The soil moisture data is depicted on Chart 2. <br /> Precipitation events in the 2007/2008 water year elicited a corresponding change in moisture <br /> content at all three depths. February, April, October, and December were heavy rainfall months <br /> (greater than 0.75 inches in the month) for the year. Nearly 3 inches of rain in February caused <br /> a rise in moisture content at all three depths, with the largest increase at the 1-foot level and the <br /> smallest at the 3-foot level. Rainfall in April (1.2 inches) caused a smaller increase at the 2- and <br /> 3-foot levels. A period of drying occurred during the summer, with the moisture content of the 1- <br /> foot level and dropped below that of the 2- and 3-foot depths. <br /> In water year 2008/2009, October rain (0.79 inches) caused a slight increase in moisture at the <br /> 1-foot level, with the two deeper probes remaining unaffected. Heavier rains in December (1.63 <br /> inches) caused a rise in the 1- and 2-foot sensors, but not the 3-foot deep sensor. January was <br /> a heavy rainfall month with 5.25 inches. That represented over one-third of the yearly average <br /> for the area deposited during a 31-day period. The moisture content continued to rise through <br /> May and then started a drying period during the summer. There was a data gap in 2008/2009 <br /> monitoring, March through April. The March through April download file was corrupted and could <br /> not be recovered. <br /> Water year 2009/2010 appears to follow a natural flow path as the 1-foot probe is dryer than the <br /> 1 two deeper probes following the summer season. Rainfall in October and November caused a <br /> rise in soil moisture at all depths at the beginning of water year 2009/2010. Soil moistures <br /> peaked in February and have slowly decreased through June. <br /> 47717.11/ST013R0532 Page 6 of 10 August 30, 2013 <br /> Copyright 2013 Kleinfelder <br />