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MEMORANDUM Project No.: 090045-001-01 December 20, 2012 To: WRIA 31 Planning and Advisory Committee cc: Mark Schuppe, Department of Ecology From: Steve Germiat, LHG; Senior Associate Hydrogeologist Timothy J. LHG Principal Hydrogeologist Re: Strategies for ASR Compliance with Groundwater Quality Standards, WRIA 31 Horse Heaven Water Storage Appraisal Assessment Ecology Grant No. G1100215 This memorandum outlines options to achieve regulatory compliance for water quality if there is initiative to permit an aquifer storage and recovery (ASR) project for irrigation supply as a component of the Water Resource Inventory Area 31 (WRIA 31) Horse Heaven water storage project. The options are derived primarily from review of Washington State’s current policy and processes for addressing potential water quality impacts as part of ongoing ASR pilot projects. This assessment fulfills Task 1.12 under the WRIA 31 Horse Heaven Water Storage Appraisal Assessment funded by Washington State Department of Ecology’s (Ecology) Office of Columbia River (OCR) Grant No. G1100215. The following sections of this memorandum briefly summarize the State’s antidegradation policy as applied to ASR, describe other eastern Washington ASR projects addressing compliance with the water quality standards, and present options for a prospective Horse Heaven ASR program to comply with water quality standards. Background: State Antidegradation Policy Applied to ASR If the water to be stored during ASR has chemical constituents present at concentrations above that in the ambient groundwater in the storage aquifer, the storage could be interpreted to violate the antidegradation policy of Washington State’s Ground Water Quality Standards (Chapter 173-200 WAC). The State’s groundwater antidegradation policy is as follows (WAC 173-200-030(2)): a) Existing and future beneficial uses shall be maintained and protected and degradation of groundwater quality that would interfere with or become injurious to beneficial uses shall not be allowed. earth+w a t e r Aspect Consulting, LLC 401 2nd Avenue S. Suite 201 Seattle, WA 98104 [PHONE REDACTED] www.aspectconsulting.com ---PAGE BREAK--- MEMORANDUM December 20, 2012 Project No.: 090045-001-01 Page 2 b) Degradation shall not be allowed of high quality groundwaters constituting an outstanding national or state resource, such as waters of national and state parks and wildlife refuges, and waters of exceptional recreational or ecological significance. c) Whenever groundwaters are of a higher quality than the criteria assigned for said waters, the existing water quality shall be protected, and contaminants that will reduce the existing quality thereof shall not be allowed to enter such waters, except in those instances where it can be demonstrated to the department's satisfaction that: i. An overriding consideration of the public interest will be served; and ii. All contaminants proposed for entry into said groundwaters shall be provided with all known, available, and reasonable methods of prevention, control, and treatment (“AKART”) prior to entry. The antidegradation policy speaks to both: not interfering with existing and future beneficial uses of the groundwater resource (WAC 173-200-030(2)(a)), and not allowing a reduction in the existing quality (WAC 173-200-030(2)(c)). In practice, subpart-030(2)(c) has been interpreted to mean that a water source for ASR containing a higher concentration of any constituent cannot be permitted for entry into a groundwater with lower concentrations of that constituent, unless the public interest is served and AKART is applied. The State ASR rule states, “The department shall give strong consideration to the overriding public interest in its evaluation of compliance with groundwater quality protection standards” (WAC 173- 157-200(2)). For the State to permit a Horse Heaven ASR program, it could not be adverse to the public interest. An ASR program for the Horse Heaven area would serve the public interest by stabilizing further drawdown of the basalt aquifer system (current sole source for irrigation water supply at distance from the Columbia River), thereby helping to sustain the region’s agricultural economy. Water Quality Compliance for Other Eastern Washington ASR Programs City of Kennewick The recently completed AKART assessment for the City of Kennewick’s ASR pilot program included a request that Ecology approve ASR pilot testing by applying the overriding consideration of public interest (OCPI) provision of WAC 173-200-030(2)(c) (HDR, 2012). Because the City of Kennewick’s ASR system would store chlorinated water, the primary water quality issue is disinfection byproducts (DBPs) in the source water at concentrations above background groundwater quality within the planned storage aquifer. The DBP concentrations meet Federal and State drinking water standards and are the same concentrations served to the City of Kennewick’s customers, so it is a regulatory compliance issue (antidegradation policy) not a public health issue. The City of Kennewick’s AKART study concluded that reverse osmosis (RO) could reduce DBP concentrations in the source water by 50 to 99 percent, but it would be economically infeasible to do that additional treatment. ---PAGE BREAK--- MEMORANDUM December 20, 2012 Project No.: 090045-001-01 Page 3 The AKART study conclusion is consistent with that reached in the WRIA 31 Watershed Management Plan regarding the City of Kennewick’s ASR: “It is the opinion of the Planning Unit, including City of Kennewick as a potential ASR implementer, that the water treatment currently conducted by City on the source water to be stored would represent AKART for the purposes of an ASR project. It would be unreasonable (disproportionately costly) to conduct additional treatment to dechlorinate water already in the distribution system, prior to its storage via an ASR well.” (WRIA 31 Planning Unit, 2008). The City of Kennewick’s proposed OCPI determination is based on: low risk to background groundwater quality, treating source water to meet background groundwater quality would be cost prohibitive, and public interest would be served by achieving a net increase in Columbia River flows during the critical summer months and optimizing use of the City of Kennewick’s existing infrastructure. Ecology is currently evaluating the AKART study and the City of Kennewick’s request for an OCPI determination. Wallula Mill A Horse Heaven ASR system would be more comparable to the ASR system for the Boise Wallula Mill, in that it would presumably store unchlorinated water and thus avoid DBP issues. The goal of the Boise ASR system is to store in the basalt aquifer unchlorinated Columbia River water during the months of December through April, when the river water is coldest, and recover the stored water for industrial-cooling use during the hot summer months instead of withdrawing warmer Columbia River water. The Wallula Mill’s current ASR pilot-test plan is to conduct membrane filtration, but not chlorination, of the river source water. The source water contains eight chemical constituents at concentrations above background groundwater quality in the storage aquifer; however, the source-water concentrations are below Federal and State drinking water standards and below numerical groundwater quality standards in Chapter 173-200 WAC. The source water has lower concentrations of fluoride, sulfide, radon, and total dissolved solids (TDS) than the background groundwater. TDS provides an aggregate measure of water quality, indicating the river water is generally of higher quality than ambient groundwater in the storage aquifer. Because the source water will not be chlorinated (disinfected), the AKART analysis for the ASR system assessed the longevity of bacteria and viruses potentially introduced into the aquifer from the source water, and concluded there is negligible risk that such pathogens would leave the Boise property (GSI and HDR, 2010). Based on the data, Ecology concluded that injecting filtered river water into the aquifer is acceptable because the aquifer water is of lesser quality than the source water to be injected, and the source water does not exceed the numerical criteria in WAC 173-200-040(2)(a). Ecology concluded that ASR would not preclude any beneficial uses of the existing aquifer water consistent with WAC 173-200-030(2)(a), and that WAC 173-200-030(2)(b) and do not apply, so determinations of AKART and OCPI are not necessary. Ecology reserves the right to change this determination upon review of data not submitted to date or upon results obtained during the pilot study (Guy Gregory, Ecology, personal communication to Dan Haller, Aspect; April 13, 2012). City of White Salmon As part of an ongoing ASR pilot test program, the City of White Salmon is conducting an AKART evaluation to address treatment of DBPs generated from chlorination of ASR source water (surplus surface water from Buck Creek). Treatment technologies being evaluated include granular-activated ---PAGE BREAK--- MEMORANDUM December 20, 2012 Project No.: 090045-001-01 Page 4 carbon (GAC) pre-treatment for DBP precursors, chloramination to reduce residual chlorine and decrease DBP generation, and enhanced watershed control to reduce chlorination disinfection requirements and DBP generation. Although the AKART evaluation is not yet finalized, the following conclusions are becoming apparent. The baseline alternative—consisting of no additional treatment, DBP natural attenuation, and overriding public interest—appears to be reasonable with regards to the antidegradation policy and the reasonability of other control methods. The ASR target zone is hydraulically isolated, there are no downgradient groundwater receptors, and simulations show that roughly 70 to 80 percent of the injected surface water would be recovered for beneficial use during ASR operations. Once the surface water is injected, the concentrations of residual chlorine attenuate within one to two days, and the DBP concentrations attenuate within the storage aquifer. The ASR target zone also provides additional filtration benefit for the injected surface water, and, by allowing natural attenuation of the DBPs, the extracted groundwater may be of higher quality than the injected drinking water. The injected surface water that cannot be captured during ASR recovery would have the benefit of several months of natural attenuation in the ASR target zone, where the natural degradation rate would be anticipated to increase farther away from the injection well, where there are no current or foreseeable users of the groundwater. Based on the weight of evidence, the AKART evaluation indicates that the public benefits of the proposed ASR project far outweigh de minimis impacts to groundwater quality. The planned water treatment for the source water—slow sand filtration and chlorination—constitutes the reasonable treatment method (AKART), and the benefits of the proposed ASR program would satisfy an OCPI determination. Therefore, the results of the AKART evaluation indicates that the City of White Salmon ASR program would comply with the State’s antidegradation policy (WAC 173-200- 030(2)(c)). Recommendations for Potential Horse Heaven ASR Water Quality Compliance It is expected that a future ASR system in the western Horse Heaven area would supply water for irrigation use, not potable (drinking water) use. Consequently, water quality standards for public water systems (Chapter 246-290 WAC) would not apply to the system, but the State Groundwater Quality Standards (Chapter 173-200 WAC), including the antidegradation policy, would apply during ASR permitting. Irrespective of water quality standards, the water to be recharged in an ASR program must contain minimal turbidity to avoid clogging the ASR well and/or the aquifer immediately around the well. Turbidity control could be achieved by a constructed water-filtration plant as exists for the Wallula Mill ASR project, or use of a slow sand-filtration system as used by the City of White Salmon. Alternatively, and likely more cost effectively, pumping from a Ranney well1 installed in the Columbia River Gravels can provide natural river bank filtration for removal of turbidity and bacteria from water to be injected for an ASR program. Significant accumulations of Columbia 1 Large-capacity well consisting of a central large-diameter caisson from which multiple lateral collectors extend outward into the gravels of the river bed. ---PAGE BREAK--- MEMORANDUM December 20, 2012 Project No.: 090045-001-01 Page 5 River Gravels are present in several areas, and lesser deposits are present in most areas, along the Columbia River shoreline within the Horse Heaven area. For example, the City of Kennewick’s Ranney collector No. 5 withdraws very high flow rates from Columbia River Gravels several miles upstream of the Horse Heaven area. The water withdrawn from the City of Kennewick’s Ranney collector No. 5 is a blend of upgradient regional groundwater and river water. Detailed analysis of that collector’s water quality confirmed to the satisfaction of the State Department of Health that the natural riverbank filtration achieves water quality with very low turbidity (below 0.04 NTU) and 99 percent removal of and Giardia bacteria, and is therefore suitable as the primary filtration method for a public water system (Western Groundwater Services, 2007). Note that the Horse Heaven Water Storage Pre-Feasibility Report (Aspect and Anchor, 2010) assumed use of a Ranney well as the source of naturally filtered water to store in an ASR program, and we continue to recommend that approach. Based on the collective information, we identify the following two options as viable to achieve water quality compliance for a potential ASR system in the Horse Heaven area: No water quality degradation. Document that naturally-filtered groundwater from a Ranney well or equivalent well in the Columbia River Gravels is of better quality than native groundwater quality in the basalt aquifer storage zone. If this is the case, ASR will not degrade groundwater quality and a determination of AKART and OCPI will not be needed, which is consistent with Ecology’s preliminary determination for the Wallula ASR project. To assess this, comparative testing of groundwater quality in the Columbia River Gravels (source) versus the Wanapum Basalt aquifer (storage zone) can be conducted. AKART with OCPI. If the intended source water is documented to be of poorer quality than ambient groundwater in the storage aquifer, but the ASR program would not impair beneficial use of the groundwater resource, then the WAC 173-200-030(2)(c) AKART and OCPI determination could be proposed, which is consistent with that being done for the Cities of Kennewick and White Salmon. Groundwater Management Area Concept Without knowing the specific water quality conditions of a specific source water and storage aquifer, another option evaluated is formal designation of the aquifer zone(s) used for ASR as a Groundwater Management Area (GWMA2), within which the groundwater’s highest beneficial use would be irrigation, not drinking water. The regulatory intent for establishing a GWMA for an area or aquifer zone is to “…protect groundwater quality, to assure groundwater quantity, and to provide efficient management of water resources for meeting future needs while recognizing existing water rights.” (WAC 173-100-010). A GWMA specific to ASR could meet this intent, as long as it did not impair the rights of other groundwater users in the area create groundwater quality or quantity problems for adjacent wells). A GWMA is developed cooperatively by Ecology with local government(s) county) and groundwater user groups. We expect that establishing a GWMA for irrigation supply would require a county overlay preventing other groundwater uses, including permit-exempt domestic wells within the GWMA. 2 Under RCW 90.44.400 and Chapter 173-100 WAC. ---PAGE BREAK--- MEMORANDUM December 20, 2012 Project No.: 090045-001-01 Page 6 Initial discussions with Ecology indicate that there is no precedent for establishing a GWMA in which a highest beneficial use other than drinking water is designated for groundwater. While the GWMA concept could be further explored with Ecology and the WRPAC (which includes local governments) if necessary, we recommend gathering water quality data specific to a prospective ASR project for the Horse Heaven area and, based on that, proceeding with one of the two options outlined above, for which there is regulatory precedent. Limitations Work for this project was performed and this memorandum prepared in accordance with generally accepted professional practices for the nature and conditions of work completed in the same or similar localities, at the time the work was performed This memorandum does not represent a legal opinion. No other warranty, expressed or implied, is made. All reports prepared by Aspect Consulting are intended solely for the WRIA 31 Planning and Advisory Committee (Advisory Committee) and apply only to the services described in the Agreement with Klickitat County. Any use or reuse by the Advisory Committee for purposes outside of the scope of Klickitat County’s Agreement is at the sole risk of the Advisory Committee and without liability to Aspect Consulting. Aspect Consulting shall not be liable for any third parties’ use of the deliverables provided by Aspect Consulting. Aspect Consulting’s original files/reports shall govern in the event of any dispute regarding the content of electronic documents furnished to others. References Aspect Consulting and Anchor QEA (Aspect and Anchor). 2010. Water Storage Pre-Feasibility Assessment Report, Horse Heaven Area, WRIA. Prepared for the WRIA 31 Planning and Advisory Committee. October 27, 2010. GSI Water Solutions and HDR. 2010. ASR-5 Well Report, Boise White Paper LLC Wallula Mill Thermal ASR Project. June 2010. HDR. 2012. City of Kennewick Aquifer Storage and Recovery AKART Analysis. September 21, 2012. Western Groundwater Services. 2007. River Bank Filtration Study, Ranney Collector No. 5, City of Kennewick, Kennewick, Washington, Final Report. January 2007. WRIA 31 Planning Unit. 2008, Watershed Management Plan, Rock-Glade Watershed (WRIA 31). January 2008. W:\090045 WRIA 31 Phase 4\Deliverables\Storage Appraisal Assessment Memo\ASR Permitting Memo - WRIA 31 Storage Appraisal Assessment FINAL.docx