ARCHIVED REPORTS XR0009215 - Laserfiche WebLink

Home Browse Search

distance to the north Single family dwellings are adjacent to the site on the south and west Refer to PLATE I for more details GEOLOGIC & GEOMORPHIC PROVINCE: The site is located near the southern end of the Sacramento Valley, a sub-province of what is referred to as the Great Valley of California It is underlain by over 20,000 feet of sands, silts, clays, & gravels derived from erosion and uplift of the Sierra Nevada Batholith to the east Relief is very flat, less than 57mi1e, with surface drainage to the southwest towards the Sacramento-Stockton delta The Calaveras river is about one rule to the north-northeast, and Mormon Slough is roughly 2 miles to the south PLATE 11, from a USGS topographic sheet, shows the site in relation to other nearby features DEPTH TO GROUNDWATER: Based upon published data, the highest water level in the last 10 years was measured at about 27' bgl It was located at 53 09' after completion of MW-1 in October, 1994 The water has gradually risen since that time to an average depth of 3 3 93' in March, 1997 The June, 1997 sampling event revealed that the water table had dropped slightly to an average depth of 34 28' }PRIOR USE OF UST's: The site had been the location of a gasoline station for many years The tanks were taken out of use in 1986, and were removed m1987 SUMMARY OF PRIOR WORK DONE: April, 1987 - Two 3,000 gallon UST's and one 150 gallon waste oil tank were removed from the property The soil samples taken from beneath the removed UST's were below detection levels for components analyzed June, 1987 - Site of removed waste oil tank was reentered and a soil sample taken at about 8 112 feet Gasoline& motor oil were detected August, 1987 - Waste oil tank site reentered & deepened to 13 1/2 feet, and a soil sample taken Only motor oil was detected October, 1989 - Waste oil site was again reentered and and a soil sample was taken at approximately 23' below grade Motor oil was detected in the sample 2