SU0004731 SSCRPT - Laserfiche WebLink

Home Browse Search

In late 200I, an Excavation Permit was secured by Wong Engineers through San Joaquin County to remove an average of one foot of soil over the surface of the property (excluding the walnut orchard). Approximately 5,000 truckloads were removed from the property with no underground artifacts discovered or uncovered. Three electrical transformers are found on a pole directly south of proposed-Parcel 1. They are the newer type of transformer installed approximately 10 years ago; therefore, they-probably do not contain polychloride biphenyl(PCB) laden oil. The transformers do not show any sign of oil leakage. If these transformers were to leak or explode, it would be the responsibility of the transformer owner(PG&E) to mitigate any environmental contamination. From revious soil suitability and nitrate 1oadin studies and other soil and groundwater investigations in t is ocale, it is known that there can be veryhigh concentrations of nitrate in the un erl in »mss, .n .t.: .,_ y g water tableHowever, the dri� nkmg water r a uifers teste contain_alnt no n„ rtrate, his ` may e attributable to San Joaquin River influence. High nitrate concentrations in the groundwater III this region may be due to agricultural fertilizer inputs, and organic matter decay that has occurred in the Delta region for centuries, impacting the notably shallow.groundwater. PUBLIC ENVIRONMENTAL RECORD/DATA SOURCES As noted, static groundwater is found approximately 12 feet under the property. This is based upon groundwater studies done in the locale of the subject property. Also, the 1999 Lines of Equal Depth to Groundwater map confirms this depth. From the referenced groundwater studies, a very accurate groundwater directional flow was determined from monitoring wells to be North 33° East. This is also confirmed by the 1999 Lines of Equal Elevation of Groundwater. t � A groundwater depth of 12 feet can be considered a shallow groundwater elevation which can be 1 readily impacted from point source hazardous materials releases, agrichemicals such as pesticides/ herbicides, or nitrates from fertilizers. The degree of impact from agrichemicals can be mitigated t, when there are intervening layers of clay soil or hardpan.down to the static water table depth. It is known that hardpan strata do exist under the surface soils in this area that may impede agrichemical impact. There are no records of underground storage tanks (USTs) at the subject property address. This is illustrated on the attached GeoTracker Site Map, which shows no Unde ground Storage Tanks (USTs) or Leaking Underground Storage Tanks (LUSTs)tanks near the site, or on the west side of Interstate 5. Underground Storage Tank and LUST sites are shown approximately 1.0 miles to the east and northeast of the property and can be considered crossgradient: EHD LOP/NON LOP Sites dicate oes e o�Frewert Rooad, approximately 1.5 miles to the south of the property (SiteID SD0000857). No fo �rmation is known from this site on Frewert Road. It can be considered upgradient and possibly crossgradient, and highly unlikely to impact the subject property. Potential environmental impacts from past, present or future facilities within a one mile radius is unknown at this time, but highly unlikely. Page -3- Chawy Conswrting