Delta tunnel: geotechnical drilling done in violation of county ordinances to protect groundwater

The Department of Water Resources and the Delta Conveyance Design and Construction Authority are doing extensive engineering work to assess potential designs for a single Delta tunnel. On June 10, 2019, the Department of Water Resources began geotechnical drilling in the former WaterFix project tunnel alignment and a former WaterFix project intake location. According to the DWR website, the geotechnical drilling is at 19 sites in three Delta counties (San Joaquin, Sacramento, and Contra Costa.) The work requires drilling of 6.5 to 8 inch boreholes to a depth of 150-200 feet. The drilling reportedly requires a crew of five to six people for up to 11 days at each site.

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Drilling crew in Courtland

The Sacramento-San Joaquin Delta is a sensitive area and borehole drilling requires special sealing to prevent contamination of groundwater. On June 7 and June 14, 2019 the counties of San Joaquin and Sacramento notified DWR that the geotechnical work required a well drilling permit. On Monday, June 17, 2019, the Sacramento County Environmental Management Department issued a Stop Work Order for the drilling in Sacramento County. On Thursday, June 20, 2019, the San Joaquin County Environmental Health Department gave Victoria Farms on Victoria Island in the South Delta a Notice to Abate for unpermitted well drilling. The abatement notice documented that Victoria Farms was under court order to allow the drilling.

On Thursday, June 20, the Sacramento County Superior Court granted a Temporary Restraining Order to Sacramento County to enjoin the geotechnical drilling for 21 days. Chris Hunley, the Sacramento County Environmental Specialist who issued the Stop Work Order, stated in a declaration in support of the order:

Unregulated drilling performed in connection with investigations of hydrologic or geologic conditions can be harmful and detrimental to water quality, including potable drinking water supplies, because the drilling can remove or open up preexisting underground geologic layers between aquifers and expose groundwater resources to pollutants, contaminants and sediments from other aquifers that had no prior hydrologic connection.

Most of the Delta area of Sacramento County relies upon wells for drinking water supply. The Sacramento Delta is a sensitive area with respect to groundwater quality. The Courtland area has special annular sealing material requirements to protect high quality waters from degradation by poor quality waters via pathways that are unsealed or improperly sealed. The potable groundwater supply exists at a depth of roughly 120 feet and lower. While borings are not water supply wells, improper construction of borings can potentially negatively affect the region’s drinking water aquifer by creating a hydrologic connection between the dirtier river seepage water at shallower depths and the separate, cleaner groundwater in the lower aquifer.

An improperly constructed or drilled boring could cause irreparable harm to public health because domestic well water could be infiltrated and contaminated by non-potable water from other aquifers as a result of drilling a single bore through multiple aquifers.

As reported by Matt Fleming at CalWatchdog, Sacramento County previously had problems with Caltrans claiming exemption from local agency permitting for geotechnical work and doing improper drilling. In 2014 Sacramento County threatened to fine Caltrans millions of dollars for drilling hundreds of borings over a period of decades in violation of state laws aimed at protecting groundwater. Under pressure from Sacramento and San Joaquin County and other local agencies, Caltrans announced their intent to follow local groundwater protection ordinances and outlined a plan to locate wells throughout the state and work under the proper license.

The Department of Water Resources does not have a similar policies. DWR and the Delta Conveyance Design and Construction Authority are proposing to delete Term 3b from the Joint Exercise of Powers Agreement which requires compliance with local permits:

In carrying out its obligations under this Agreement, and without regard to the named Permit holder, the Authority and its agents shall comply with all conditions of all applicable federal, State, or local Permits issued for design and construction of the Conveyance Project.

The next hearing on Sacramento County’s filing to enjoin DWR from doing further geotechnical drilling without the required county permits will be in Sacramento County Superior Court on July 11 at 2:00 pm.

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