4
Conclusions and Recommendations

The Regional ASR Project Management Plan (PMP) clearly responds to the issues identified earlier by the South Florida Working Group ASR Issue Team and later by the CROGEE. The report recognizes the importance of acquiring information through the proposed Regional Study to resolve or better understand the issues that are involved with the consequences of implementation of ASR regionally in south Florida at the unprecedented scale of 1.7 billion gallons per day. The PMP goes a long way to providing the needed information. It is comprehensive, for the most part, and is linked well to the pilot ASR studies. The authors of the document should be commended for the effort that went into producing the plan and for the comprehensiveness of the proposed study.

The most important overall improvement to the document would be a greater attention to the CERP principle that “each incremental step [be] viewed as an experiment accompanied by one or more hypotheses that predict how that step will improve the system” (USACE, 1999), a concept generally termed adaptive management. Some of the task descriptions suggest that the study will be conducted as a relatively routine engineering exercise rather than a comprehensive and integrated scientific study to “investigate regional technical and regulatory issues governing the feasibility of full-scale ASR implementation…and develop tools to assess the feasibility and increase the level of certainty of successful ASR implementation,” which is the stated objective of the study. This structure is of some concern given that results of the regional study may show that ASR at the scale being proposed is not feasible due to hydrogeological, geochemical, ecological, or other reasons. In such cases, the proposed plans to (1) apply the model (or collect the sample), (2) collect the results, and (3) move on to the next task will not be appropriate. Additional advanced consideration is warranted concerning what to do if the results of some phase(s) indicate that ASR, as originally planned, will not work.

The regional modeling described in Task 9 may come closest to this ideal; in this task the plan specifically discusses multiple model runs for a range of alternatives (in terms of well locations and numbers). Likewise, the flow chart of Figure 3, which shows “adaptive feedback” loops between water quality, ecological, and toxicological investigations, is a useful tool that might be more broadly applied elsewhere in the report. The PMP acknowledges the need for some flexibility in modification of the plan if early results warrant changes, and this is commendable. However, the question remains whether the overall study plan will be sufficiently flexible to allow for evaluation of alternative plans/procedures if a particular aspect of the original plan is problematical. Articulation of specific hypotheses within the PMP is highly desirable, and this approach should be coupled with a plan that ensures evaluation of results in



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Regional Issues in Aquifer Storage and Recovery for Everglades Restoration 4 Conclusions and Recommendations The Regional ASR Project Management Plan (PMP) clearly responds to the issues identified earlier by the South Florida Working Group ASR Issue Team and later by the CROGEE. The report recognizes the importance of acquiring information through the proposed Regional Study to resolve or better understand the issues that are involved with the consequences of implementation of ASR regionally in south Florida at the unprecedented scale of 1.7 billion gallons per day. The PMP goes a long way to providing the needed information. It is comprehensive, for the most part, and is linked well to the pilot ASR studies. The authors of the document should be commended for the effort that went into producing the plan and for the comprehensiveness of the proposed study. The most important overall improvement to the document would be a greater attention to the CERP principle that “each incremental step [be] viewed as an experiment accompanied by one or more hypotheses that predict how that step will improve the system” (USACE, 1999), a concept generally termed adaptive management. Some of the task descriptions suggest that the study will be conducted as a relatively routine engineering exercise rather than a comprehensive and integrated scientific study to “investigate regional technical and regulatory issues governing the feasibility of full-scale ASR implementation…and develop tools to assess the feasibility and increase the level of certainty of successful ASR implementation,” which is the stated objective of the study. This structure is of some concern given that results of the regional study may show that ASR at the scale being proposed is not feasible due to hydrogeological, geochemical, ecological, or other reasons. In such cases, the proposed plans to (1) apply the model (or collect the sample), (2) collect the results, and (3) move on to the next task will not be appropriate. Additional advanced consideration is warranted concerning what to do if the results of some phase(s) indicate that ASR, as originally planned, will not work. The regional modeling described in Task 9 may come closest to this ideal; in this task the plan specifically discusses multiple model runs for a range of alternatives (in terms of well locations and numbers). Likewise, the flow chart of Figure 3, which shows “adaptive feedback” loops between water quality, ecological, and toxicological investigations, is a useful tool that might be more broadly applied elsewhere in the report. The PMP acknowledges the need for some flexibility in modification of the plan if early results warrant changes, and this is commendable. However, the question remains whether the overall study plan will be sufficiently flexible to allow for evaluation of alternative plans/procedures if a particular aspect of the original plan is problematical. Articulation of specific hypotheses within the PMP is highly desirable, and this approach should be coupled with a plan that ensures evaluation of results in

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Regional Issues in Aquifer Storage and Recovery for Everglades Restoration each step in a timely manner to assure flexibility and implementation of alternative procedures or approaches in place of those that are problematical or do not work. A moderate number of the tasks in the PMP are not described in enough detail to allow for a substantive critique of methods at this stage. While this is understandable given the scope of the effort, these include such important topics as tracer tests, numerical modeling, interpretation of bioassay results, packer test intervals, and sampling frequency. These topics deserve additional attention in later drafts. Ecological and water quality studies are described both in descriptions of tasks 10 through 13 and, somewhat independently, in Appendix L. Unfortunately, the task descriptions and the appendix are not well integrated, and sometimes appear contradictory. The writers of the PMP are urged to make these sections more consistent with each other. Based on the points raised in comments the specific tasks and functional area plans, the following recommendations are of particular importance: The proposed additional monitoring at the pilot sites is a good step, but probably still does not go far enough in terms of numbers of wells and well nests to characterize both hydraulic and biogeochemical processes. Vertical and horizontal heterogeneity of the aquifer system will make this a difficult task that will require extensive testing. Likewise, recharge of the ASR wells should continue, if at all possible, until some time after the injection water is detected at all of these monitor wells, to understand the physical and chemical behavior of the system as fully as possible. Likewise, improved understanding of potential geochemical reactions should be a priority all pilot sites. This may require additional monitoring during cycle testing beyond that anticipated in the PMP. Given the heterogeneity of the Florida Aquifer system (FAS) with respect to salinity and physical properties at existing ASR sites, there may be significant variability in these properties from site to site. Some of the funds necessary to expand such monitoring and sampling should come through de-emphasizing continuous coring. While coring can be useful, it is costly and may yield unreliable and non-representative data. Given these limitations, it might be prudent to reduce the coring program and use the savings to support installation of additional monitoring wells for field tests of hydraulic properties and for hydrogeochemical characterization. Column studies are proposed to assess interactions between microorganisms and the subsurface materials. Due to the presence of fractures and other features in the FAS, it will be difficult, if not impossible, to obtain representative, quantitative information on transport using column studies. Such results should be treated with caution. The proposed bioassays and mesocosm studies emphasize response of individual taxa rather than community- and ecosystem-level effects. However, these studies may reveal only sublethal effects (e.g., altered growth rates) of contaminants on the sampled organisms. Such results would be difficult to extend to impacts on the larger ecosystem (e.g., shifts in community composition or changes in frequencies of algal blooms), for which little monitoring is proposed. Thus, the ASR Regional Study’s ecological monitoring and research components are poorly connected to the ecosystem- and community-level restoration objectives of CERP. This can be remedied by adding monitoring and assessment of ecological indicators to the proposed bioassays of Task 13. In coordination with other CERP science initiatives such as RECOVER, an opportunity exists to develop indicators that can be employed in both system-wide monitoring and the ASR Regional Study.

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Regional Issues in Aquifer Storage and Recovery for Everglades Restoration The extended bioassay testing and monitoring of biological impacts are expected to occur over six- to twelve-month cycles. This sampling period may need to be longer to allow assessment of potential long-term effects on community composition, especially given interannual variability in factors such as rainfall, temperature, extreme events, etc. Surface water quality modeling and ecosystem modeling tends to focus on Lake Okeechobee. However, it appears more likely that negative effects of ASR-recovered water could occur within the Everglades itself. This is where surface waters are low in nutrients and dissolved solids, and where input, either directly or via pathways that include Lake Okeechobee, of recovered ASR water with relatively high ionic strength would represent a major ecological change. More emphasis should be placed on modeling of these more sensitive ecosystems and identifying water quality changes that could cause irreversible shifts in community composition.

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