RWQCB Invites Public Comment on Its Letter to City Injection Plan
• Panel Is Responding to Report Submitted by Malibu Last Month on Proposal to Handle Groundwater
BY BILL KOENEKER
In a somewhat unusual move, the state water boards are accepting public comments on their forthcoming comment letter on a report prepared by the City of Malibu on its proposed groundwater injection plan.
Based on the terms of the memo of understanding between the city and the water boards, municipal officials submitted a conceptual groundwater injection plan that is "based on field testing and modeling" on June 29, 2012, according to Rebecca Chou, chief of the agency's groundwater permitting and land disposal section of the Los Angeles Regional Water Quality Control Board.
"The Regional Board intends to provide a letter to the City of Malibu regarding the report. The regional board is accepting public comments on the technical portion that may be incorporated into its review letter to the City of Malibu. To be considered in its review letter, public comment letters to the Regional Board must be received by 4 p.m. on August 9, 2012.
Written comments shall be submitted electronically to email@example.com, or sent to California Regional Water Quality Control Board, Los Angeles Region, 320 W. 4th Street, Suite 200, Los Angeles, 90013. Attn: Dr. Eric Wu, Chief of the Groundwater Permitting Unit.
Plans for a proposed Civic Center wastewater treatment plant have been outlined for disposal of the treated effluent by groundwater injection, which has become the preferred method, but require feasibility tests to confirm the viability of groundwater injection of the treated effluent in the Civic Center area and the estimated groundwater injection capacity in that area. The actual feasibility studies have yet to be done.
The city council recently held off on spending its own money, $1.5 million for the study, to wait and see if the proposed Community Facilities District would come up with the cash to finance the rest of the study and other work, including an Environmental Impact Report.
The tests are to determine if up to 500,000 gallons of effluent can be injected on a daily basis.
The first goal of the study is to determine the extent and hydraulic properties of what are called the Civic Center gravels.
"The intent of this work is to assess if the hydraulic properties of this unit are adequate to meet project needs. Three exploratory test wells will be installed to bedrock for this purpose. Pumping tests will be conducted to each of the wells to measure local aquifer hydraulic properties. If these tests show that the Civic Center gravels are reasonably transmissive, more in-depth investigative work, Phase 2, may be conducted," a consultant's document states.
Water sampling tests will be taken, along with other water testing and analysis including an assessment for the potential for adverse geochemical reactions that could occur with groundwater injection of treated wastewater. Aquifer properties will be measured and other related water sample tests undertaken.
Phase 2 would be to determine if the Civic Center gravels could receive and transmit the planned quantities of up to approximately 500,000 gallons per day of injected water "without adverse consequences."
Many other tests are included in Phase 2 besides geophysical and geotechnical assessments, including conducting a geotechnical evaluation of the allowable pressurization of the system during injection, preliminary modeling simulations and geochemistry assessment.
Phase 3 consists of conducting full scale testing, confirming feasibility and finalizing the basis of design. A full-size well will be drilled and the installation of deep multi-level monitoring wells will take place with the installation of full-scale test wells.
Some of the last tasks include final model simulations, meeting with regulators and preparation of a basis-of-design report.