Conceptual Model of Hydrologic and Thermal Conditions of the Eastbank Aquifer System near Rocky Reach Dam, Douglas County, Washington

U.S. GEOLOGICAL SURVEY
Scientific Investigations Report 2008–5071

Table 6. Summary of temperature trends in the Eastbank Aquifer system, Douglas County, Washington, 1991–2007.

[Locations of wells are shown in figure 2. USGS well No.: See figure 4 for explanation of well-numbering system. Latitudes and longitudes of the wells are on file with the U.S. Geological Survey. Abbreviations: USGS, U.S. Geological Survey; X, not analyzed because too few or no data points; na, not applicable; –, not available]

Local well name	USGS well No.	Hydrogeologic unit at depth of temperature probe	Is indicated trend statistically significant at a confidence level of 95 percent?					Mean annual increase of annual maximum temperature, 1999–2006 (degrees Celsius)	Hydrogeologic unit to which well is open	Primary use of water since completion of Rocky Reach Dam
			Decreasing time lag between annual minimum and/or maximum river and well temperatures			Increasing ratio of annual temperature range of well divided by annual temperature range of river, 1999–2006	Increasing annual maximum well temperature, 1999–2006
			1991–2007	1991–98	1999–2006		Increasing annual maximum well temperature, 1999–2006
Temperature probe in Upper Aquifer or Clay Confining Unit
CD8	24N/20E-35R01	Sand lens in Clay Confining Unit	X	Yes	X	X	X	X	Clay Confining Unit	Monitoring
CD10	24N/20E-35Q01	Sand lens in Clay Confining Unit	No	Yes	No	X	No	na	–	Monitoring
CD47	24N/20E-35Q02	Clay Confining Unit	No	No	No	Yes	Yes	0.12	Lower Aquifer	Monitoring
CT3	24N/20E-35Q03	Clay Confining Unit	No	No	No	X	Yes	.14	Lower Aquifer	Hatchery
TH5	24N/20E-35G01	Upper Aquifer	No	No	No	No	No	na	Upper Aquifer	Monitoring
Temperature probe in Lower Aquifer or Combined Aquifer
LR2-W	24N/20E-35H02	Combined Aquifer	Yes	Yes	Yes	Yes	Yes	0.23	Combined Aquifer	Irrigation
TH1	24N/20E-35K05	Lower Aquifer	No	No	No	No	Yes	.26	Lower Aquifer	Monitoring
TH4	24N/20E-35K02	Lower Aquifer	No	No	No	Yes	Yes	.22	Lower Aquifer	Monitoring
TH6	24N/20E-35G02	Combined Aquifer	Yes	Yes	No	Yes	Yes	.19	Combined Aquifer	Monitoring
TH7	24N/20E-35K01	Lower Aquifer	Yes	Yes	No	No	Yes	.18	Lower Aquifer	Monitoring
TH8	24N/20E-35K04	Lower Aquifer	Yes	Yes	No	No	No	na	Lower Aquifer	Monitoring
TH9	24N/20E-35K03	Lower Aquifer	Yes	Yes	No	Yes	Yes	.19	Lower Aquifer	Monitoring

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