Regional Issues in Aquifer Storage and Recovery for Everglades Restoration A Review of the ASR Regional Study Project Management Plan of the Comprehensive Everglades Restoration Plan (2002) / Chapter Skim
Currently Skimming:
2 Tasks
2 Tasks
Pages 11-36
The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.
From page 11... ...
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" (CERP, 2002~. 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.
|
From page 12... ...
will be completed in July 2002 for the Lake Okeechobee ASR pilot project, in September 2002 for the Hilisboro pilot project, and in November 2002 for the Caloosahatchee pilot project. Furthermore, the May 2002 Progress
|
From page 13... ...
Sublask 4.2 - Characterize Hydrogeochemical System The overall description of this subtask states that it involves "compilation of existing groundwater quality data." However, the individual subtask descriptions indicate that this subtask will actually involve collection and analysis of water samples from existing and new wells, both before ASR operations and during pilot project cycle testing. A better definition of this task would be that it involves "characterizing the geochemistry of ambient (or native)
|
From page 14... ...
Although there will be four new "multi-zone" wells installed near ASR pilot project wells to provide additional monitoring capabilities, the text and the sampling schedule listed in Appendix F Tab B assume detailed cycle test sampling of only two monitor wells that will be installed as part of the pilot projects. Descriptions of the pilot projects imply that all monitor wells will be sampled to some extent, and the multi-zone wells could provide particularly valuable data on the vertical variations in migration of the injected freshwater bubble.
|
From page 15... ...
For the purposes of cost estimation, the PMP assumes two ASR cycle tests, including a short duration test in which recharged water is stored for approximately one month, and a long duration test in which a significantly greater volume of recharged water will be stored for six months to one year. Given that neither of these time frames approaches the multiyear storage that may occur during full scale operation of the regional systems, extrapolation of geochemical results to expected water quality changes during full scale operation would require a good understanding of reaction rates.
|
From page 16... ...
The document states that field tracer tests will be performed, and then column studies may be initiated, pending the results of the literature review and tracer studies. The rationale behind conducting column studies after field tracer studies is not clearly articulated.
|
From page 17... ...
which must result in significant honzontal-to-vertical anisc~trc~nv of the unit. ~ _ ~ ~ r ~ Another consideration when conducting column studies in an effort to mimic field-scale transport processes is the observation that many hydraulic properties (e.g., hydraulic conductivity and porosity)
|
From page 18... ...
At the least, this assumption at the scale of the test should be supported by an analysis of available data from hydraulic and geotechnical tests on these units. As noted in the previous CROGEE review of ASR pilot studies, these studies of pressure induced changes and fracture potential should be combined with results of the regional hydrogeologic models in order to assess the potential for fracturing during full-scale ASR operation.
|
From page 19... ...
This again points to the necessity of careful placement of monitoring wells to detect pressure head changes within the wellfield as well as at the welIhead. Given the uncertainty of the local and regional hydraulics, the pilot projects probably need at least one on-site monitor well within 100-500 feet.
|
From page 20... ...
TASK 6 - HYDROGEOLOGIC FIELD DATA COLLECTION Subtask 6.1 - Formulate Field Data Collection Plan This subtask explicitly recognizes the potential need for revision of field plans in response to new knowledge acquired during earlier stages of the study, and thus is consistent with an adaptive management approach. Subtask 6.2.1 - Test Well Pairs Leakance of the Upper Floridan aquifer, or more selectively the target ASR zones, is an important hydraulic parameter for construction of the numerical models for simulating head changes and solute transport.
|
From page 21... ...
Different sets of zones might be optimal for different objectives such as characterizing vertical variations in native groundwater chemistry, identifying first arrival of injected water during tracer tests, or constraining the geometry of the freshwater "bubble." Overall, as noted in preceding discussions under Task 5, a single monitoring well per site will make characterization very difficult. There is a potential that pressure head changes and fresh water plumes may not coincide, and may even migrate in different directions.
|
From page 22... ...
As in the case of the test well pairs, water quality sampling could be conducted in conjunction with packer testing to provide additional constraints on vertical variations in native groundwater chemistry. This information might also be useful in selecting open intervals for completion of the wells as monitoring points.
|
From page 23... ...
In particular, it should be kept in mind that the direction of fresh water plume migration may not correspond to directions of maximum changes in pressure head. With an adequate monitoring network in place near a pilot ASR well, monitoring of conservative solutes that are present in or added to the injected water during ASR cycle tests could provide an additional set of tracer data.
|
From page 24... ...
During long-term operation, annual production and injection performance efficiency testing may be useful to identify wells that are candidates for repeated logging to interpret changes in hydraulic properties. Perhaps the most useful method proposed in this subtask is the placement of a wellcharacterized sample of the FAS in the well during cycle tests, with re-characterization of the sample after completion of the cycle testing.
|
From page 25... ...
The proposed thin section work may be useful for the sequence stratigraphy analysis, but it may not provide useful data on porosity, since the porosity of primary interest is that caused by the megascopic fractures and solution conduits that will not be captured in the thin sections. A minor point is that while the PMP title for this subtask specifies "existing core and cuttings," the more detailed subtasks also inclucle analysis of new core ~~ Wed ~ SWAM ~~ ~ ~ ~ ~ V ~ ~ ~ _ ~^ _ ~ Subtask 7.3 - Geochemical Analysis of Rock Matrix A fairly comprehensive set of analyses is proposed in this subtask.
|
From page 26... ...
The PMP states that the task "Regional Model Development - Phase I" will begin in August 2003, directly following the task "Define Preliminary Hydrogeolog~c Framework." However, the text suggests that much of the initial work on the modeling will be directed towards choosing an appropriate code and developing algorithms to handle density dependent flow. Although the final mode} is intended to be capable of handling densitydependent flow, initial regional-scale modeling efforts employing available codes that do not have the capability to handle variable density problems may still be useful to guide the testBilling program and associated data acquisition as well as the aquifer performance test program.
|
From page 27... ...
As recommended in the previous CROGEE review of ASR pilot studies, experimental
|
From page 28... ...
-- ' -- r ~ 1 A: Sublask 11.2 - Early Source/Receiving Water Quality Monitoring Five ASR Pilot intake/discharge locations are to be monitored, but there is no information about which sites will be monitored, or how they will be distributed geographically and in terms of their discharge waters. The scope indicates that a broad array of parameters will be measured, as well as chemical analysis of periphyton, macrophytes, sediment, fish and mollusks.
|
From page 29... ...
It seems much more likely that negative effects of ASR-recovered water could occur within the Everglades itself, 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.
|
From page 30... ...
It refers forward to Subtask 13.5 for details, but the latter section deals primarily with fis~mollusk mesocosm tests designed to evaluate radionuclide bioaccumulation, not mercury. In turn, this section refers to Subtask 13.4 for a brief description of merc~y methylation testing, which involves mesocosms to evaluate effects of recovered ASR water at five pilot wells on mercury methylation rates.
|
From page 31... ...
The native plants do not die because of high nutrient levels, they simply are out-competed by the cattails when nutrient levels are elevated. -a A -- -- -- - -- -- I -- -- -- -- -- -- -- -- -- r Subtask 13.2 - Extended Bioassay Testing The stated purpose of this task is, very appropriately, to examine longer-term ecological effects of water recovered from ASR pilot facilities on native aquatic biota.
|
From page 32... ...
~ .2) describes important components of the ecological studies not mentioned in the Project Scope, such as evaluating the effects of duration of storage of ASR water, dilution with surface water upon recovery, and the seasonality of release.
|
From page 33... ...
Furthermore, the effects of discharged ASR water also may be greatly influenced by additional factors, such as rainfall and season of discharge, and such variability may not be measurable in these relatively short duration survey periods. APPENDIX L, SECTION 3.2.3.1 - ECOLOGICAL INDICATORS Ecotoxicological and ecological field studies (Task 13)
|
From page 34... ...
The benefits of using indicators may be seen by analogy with the proposed use of the hydrodynamic model for Lake Okeechobee, which is advocated partly because it contains a link between water quality and submerged vegetation that enables analysis "at a scale that is not possible using only controlled bioassay experiments" (Appendix it, 3.2.~.3~. Collecting data on ecological indicators potentially could lead to similar links for other organisms at this larger scale.
|
From page 35... ...
Discrepancies in the timetable for ecological studies and monitoring of water quality need to be clarified. The schedule in Appendix C indicates that the first phase of Environmental Effects Evaluation (Task 10.4)
|
Key Terms
This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
More
information on Chapter Skim is available.