Laserfiche WebLink
Musco Family Olive Comfy - 4 - 27 July 2006 <br /> Monitoring Well MW-11 <br /> Well MW-11 was installed to a total depth of 45 feet bgs. The well was installed with 5 feet of <br /> 0.010-inch machine slotted well screen. When the well boring was installed, first ground water <br /> was encountered at approximately 38 feet bgs, but rebounded to a static water level of 36 feet <br /> bgs. According to the log, well screen was set in a thin band of moist to very moist <br /> unconsolidated sediments. Over time, groundwater has declined and depth to water <br /> measurements or ground water samples have not been collected since August and May 2003, <br /> respectively. Well MW-11 is therefore out of compliance with WDR No. R5-2005-0024, <br /> Finding #27 that states: <br /> • If specific wells that monitor the Units remain dry over four consecutive seasonal <br /> sampling events, the Discharger shall be required to propose additional wells to comply <br /> with ground water detection monitoring requirements. <br /> Monitoring Well MW-17 <br /> Well boring MW-17 was drilled to a total depth of 65 feet bgs, 20 feet beyond the depth of well <br /> MW-11. The well was set with 20 feet of 0.010-inch machine slotted well screen. Ground <br /> water was initially encountered at 59 feet bgs and rebounded to a static water level of 58 feet <br /> bgs. According to the boring log, groundwater was not encountered above 58 feet bgs in well <br /> MW-17. Ground water measurements taken from well MW-17 since June 2005 indicate <br /> ground water levels are rising in this well. Depth to water measured in November 2005 was <br /> 50.60 feet bgs. When lithologies of well MW-17 are compared to well MW-18 (installed 10 <br /> feet east of MW-17) there appears to be consistency and good correlation to a depth of 65 <br /> feet bgs. Based on this comparison and correlation, it appears that well MW-17 is monitoring <br /> the shallow ground water from 50 to 65 feet bgs. <br /> Deep Wells MW-12 and MW-18 <br /> Monitoring well MW-18 was installed to monitor deep groundwater beneath the site. It was <br /> installed to a total depth of 100 feet bgs and fitted with 20 feet of 0.0`I0-inch machine slotted <br /> well screen. According to the boring log of MW-18, ground water in well MW-18 was first <br /> encountered at approximately 60 feet bgs, similar to well MW-17. Since well MW-18 was <br /> installed to monitor deep ground water, this ground water zone was not screened. <br /> Below the depth of 70 feet bgs, which appears to be the bottom of shallow ground water, the <br /> well boring encountered a "wet" gravel layer at an approximate depth of 80 feet bgs. This <br /> gravel layer correlates to a gravel layer logged in boring MW-12 at approximately 82 feet bgs, <br /> which also monitors the lower water bearing zone. Well log W-3 also indicates the gravel layer <br /> was encountered at approximately 80 feet bgs. Both MW-18 and MW-12 boring logs indicate <br /> the gravel layer is separated from the lower water bearing zone by clayey silt that ranges in <br /> thickness from approximately 4 to 10 feet. According to the graphical well log, the gravel layer <br /> encountered at approximately 80 feet bgs in well MW-18 is screened. However, the gravel <br /> layer shown in the boring log of well MW-12 appears to be cutoff by the bentonite transition <br /> seal. Water levels in well MW-12 and MW-18 appear to be controlled by deep ground water <br />