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Diamond Springs Parkway Phase I ESA

Youngdahl Consulting Group, Inc. worked the Diamond Springs Parkway (DSP) project area including 63 parcels located east of Missouri Flat Road and north of Pleasant Valley Road in Placerville and Diamond Springs, California.

Diamond Springs Parkway is proposed to improve traffic circulation along Pleasant Valley Road and Missouri Flat Road. The project area included parcels located in a setting of active commercial, industrial, residential, and vacant properties. This area was formerly used for agricultural purposes, as a part of a railroad depot and yard, and as a lime plant. Highway 49 has been an active right-of-way for over 100 years.

Historically, the Diamond & Caldor (D&C) Railway and the Diamond Lime Mineral Plant were located within the footprint of the DSP. Diamond Springs Station was part of the D&C Railway yard. In 1904 the D&C Railway line connected the Caldor Lumber Mill. The Diamond Springs Station, etablished 1904, depot included an engine house, machine shop, car shop, truck shop, oil storage and several warehouses. Agriculture within the project area consisted of fruit tree and grape production and pasture land and because of this specialized testing was required. Chlorinated and lead arsenate pesticides were typically applied to orchards for pest control; as well as, Smudge pots used to create a layer of warm air and smoke to protect the crops from frost. Smudge pots typically burn liquid fuels including kerosene, diesel fuel or oil. 


We worked closely with Mr. Dave Johnston of The El Dorado County Department Of Environmental Management to clarify an otherwise confusing trail of information regarding Bunker “C” Oil contamination and diesel groundwater contamination. The report concluded that recognized environmental conditions (RECs) and potential RECs (P-RECs) are present within the project area. The RECs and P-RECs were presented and categorized into one of five categories based on current or historic use: industrial, agricultural, railroad, right-of-ways, and residential. These RECs will be further addressed prior to construction of the arterial roadway.

Project Details


Diamond Springs, CA, USA


El Dorado County Department of Transportation


Laboratory Testing

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