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2000 Progress Report: Community Values and the Long-term Ecological Integrity of Rapidly Urbanizing Watersheds
EPA Grant Number: R825758Title: Community Values and the Long-term Ecological Integrity of Rapidly Urbanizing Watersheds
Investigators: Beck, Michael B. , Norton, Bryan G. , Patten, Bernard C. , Porter, Karen G. , Rasmussen, Todd C. , Steinemann, Anne C.
Current Investigators: Beck, Michael B. , Norton, Bryan G. , Patten, Bernard C. , Rasmussen, Todd C. , Steinemann, Anne C.
Institution: University of Georgia , Georgia Institute of Technology
EPA Project Officer: Perovich, Gina
Project Period: June 1, 1998 through May 31, 2001 (Extended to February 28, 2004)
Project Period Covered by this Report: June 1, 2000 through May 31, 2001
Project Amount: $849,999
RFA: Water and Watersheds (1997)
Research Category: Water and Watersheds
Description:
Objective:The project seeks to integrate ecological, hydrological, and social/policy sciences in a study of a rapidly urbanizing watershed (Lake Lanier, Georgia), where preservation of long-term ecological integrity is perceived as being at stake. More specifically, our goals are to: (1) develop a concept of environmental decision-making in which science-based models are responsive to identified community values, as they evolve in both the short and long term; (2) develop and apply a procedure for identifying those scientific unknowns crucial to the "reachability" of the community's desired/feared environmental futures; and (3) improve understanding of basic aspects of lake ecosystem behavior, with special reference to the roles of the microbial foodweb, sediment-nutrient interactions, and geochemistry. Research towards the first of these goals is expected to culminate in a more general framework, to which we shall refer as "adaptive community learning", to be facilitated over time with continual mutual feedback between the formation of stakeholder concerns and exploration of their plausibility in terms of the science-based model. Progress Summary:
In the third year of our project, substantial progress has been made towards Objective 3 above, with a strong emphasis on the conduct of field work, specifically on a manipulated Piedmont pond system. Besides its disciplinary "balance," the project now has a desirable balance among field work, computational studies, and outreach to stakeholders. Under Objective 1, further preliminary results have been obtained from the survey of stakeholders, which was issued in 1999 to individuals from various backgrounds, broadly categorized as lay persons, professional water resources managers, and professional scientists. Survey responses revealed an extremely high concern for the well-being of Lanier and a possibly counter-intuitively yet greater concern (across the board) for the longer-term, as opposed to the shorter-term, future. All groups of respondents exhibited this kind of "reverse time preference". Further, while the lay stakeholders overwhelmingly found the discharge of (treated) municipal wastewater to be the greatest threat to this well-being, only a third of the water resources professionals considered this to be the case. There was clearly a tendency for respondents to be most troubled by threats over which they perceived they (and their cohorts) had least control. For our work under Objective 2, it is important to reiterate the primary intent of the survey: to elicit impressions of the hopes and fears of the community of stakeholders for the (longer-term) future behavior of Lanier and to express them in terms compatible with specifying quantitative target behaviors for the analysis of reachable futures. This has not proved an easy task, however. Two problems arose: (a) respondents' concerns were not expressed in a form whereby they could be easily anchored to any quantitative scale attaching to the state variables of the model; and (b) there was very little differentiation amongst the nine or so concerns listed in the survey?respondents found them all to be more or less equally vital. We have been obliged, therefore, to try and circumvent these difficulties, by moving along several alternative paths, including, in particular, designing a professionally facilitated stakeholder workshop on "Foresight for Lanier" (January 2001). Successful computational work on the analysis of reachable futures has now continued for almost two complete years.
We have made progress this year on addressing and resolving certain methodological issues and on focusing our studies on Lanier (as opposed to Lake Oglethorpe). The method of Regionalized Sensitivity Analysis (RSA) has remained essentially unchanged in the more than two decades since its first publication. Yet a crucial element of the analysis (i.e., discriminating key from redundant model parameters) is severely restricted by its heavy and usually exclusive dependence on the statistical assessment of univariate, marginal distributions. Widespread experience with models shows that the values of individual parameters may themselves not be as critical to replicating the defined behavior of the system as are the values of certain clusters of two or more parameters. In order to identify parameters that may be key to the reachability of the target future behaviors, yet be embedded in such clusters and therefore not detectable using univariate analyses, work began this year on implementing the Tree Structured Density Estimation (TSDE) algorithm, one realization of the required multivariate form of analysis. In addition, whereas in most previous applications of the RSA uncertainty arising from the model's parameters alone has been considered, our studies on Lanier now allow identification of key elements of the current state of the lake and its future inputs, both policy changes and other, essentially uncontrollable disturbances.
Under Objective 3, we implemented a substantial field monitoring program for a manipulated aquaculture pond on the Whitehall estate of the University of Georgia's School of Forest Resources (as in 1998, the first year of the project). This year (2000), this intensive program of field work was undertaken with two key, specific adaptations. First, a field test of a major hypothesis arising from the more general trend of research on Piedmont impoundments was implemented; this relates to the relationship between phosphorus (P) and iron (Fe) species in such systems. Earlier laboratory experiments (1998) had shown that P adsorbs very swiftly and strongly to the iron-rich clay soils of the Piedmont. In the 2000 experiment on the aquaculture pond, we therefore implemented a test designed specifically to compare and contrast the response of the pond to fertilization with preparations containing identical nutrient concentrations but with one of the manipulations containing a sample of soils from the pond's watershed. The results showed a dramatic difference in the response of the pond, with almost no dissolved P or ammonium-N being detectable following application of the soil-based fertilization. Second, accompanying intensive monitoring of the pond and its watershed was carried out in respect of coliform bacterial presence and propagation, as a direct response to the emergence of this from our survey as an issue of the greatest concern to stakeholders. The pond is located in an especially well designed experimental format of watershed. A large portion of this very small watershed is occupied by deer enclosures, so that the movement and fate of indicator micro-organisms through the watershed and their fate (or prosperity) in the pond, in response to perturbations (primarily precipitation), has a high probability of being successfully monitored and conceptually characterized. Sampling of the pond itself, for detection of total coliforms and E. coli (using the QuantiTray technique with Colilert media), was carried out during June through October, while sampling of the upstream watershed was begun in June and will continue into 2001. Although only tentative, preliminary results are presently available, the role of the pond in attenuating the movement of these bacteria is readily apparent.
Besides these elements of field work, our research under Objective 3 also has been directed at other issues of the basic science of understanding water-watershed behavior. Detailed analysis of the 1998 data base has allowed us to develop a biogeochemical model of the pond, for subsequent application to Lake Lanier. In contrast to most other models of impounded water bodies, ours couples an account of the conventional relationships among C, N, P (as nutrients, primarily) and chlorophyll-a, with both the carbonate-pH subsystem and the Fe-sediment subsystem. In the pond, with its high primary productivity, successful matching of the observed diurnal oscillations in both DO and pH is most sensitive to a correct description of the rate of respiration of the algal biomass. In Lanier, however, with its lower primary productivity, early work with the model indicates this might not be expected to be the case. In a similar spirit, application of our foodweb model across different scales suggests that whereas the microbial loop hypothesis is important for correctly characterizing the behavior of Lake Oglethorpe, this is not the case for Lanier. Last, in our two previous reports we have given little space to the important advances we have achieved in characterizing the disturbances entering Lake Lanier from its surrounding watershed. Knowledge of the variations in loadings of sediment and nutrients in the principal tributary flows (the Chattahoochee and the Chestatee) is especially crucial to exploration of the future response of the lake. It appears that simple regression relationships may be able to simulate patterns of loading adequately. The "validity" of the regression relationships, however, and a more detailed appreciation of the fluvial conditions promoting or reducing the scope for sediment and nutrient transport, might be examined through companion modeling studies on the neighboring Oconee River and on the Chattahoochee directly downstream of Lanier.
Future Activities:In the coming final year of the project, our sights are fixed on achieving closure with respect to defining the concept of "adaptive community learning", to which end we are planning to convene a (largely internal) seminar. Other related events include the "Foresight for Lanier" workshop, three workshops on the topic of communicating science to lay audiences through the use of the Generalized Lake Lanier Ecosystem Model (GLLEM), as well as an International Workshop on "Vulnerability of Water Quality in Intensively Developing Urban Watersheds" (May 2001; http://hilbert.forestry.uga.edu/beck/workshop.htm). A key task?in the context of the entire project?will be to report back to the Foresight Workshop participants on the results of our computational analysis of the reachability of their imagined futures. This too may well have to be realized through another workshop. With regard to our goal of improving the basic aspects of lake ecosystem behavior, we have two over-riding concerns: to test a new hypothesis on the nature of P cycling in Piedmont impoundments, in particular, its divergence from the classical paradigm; and to achieve a conceptual model of pathogen movement through the water-watershed complex, sufficient to define more incisive experimental designs, to be the subject of future research outside the scope of the present project.
Journal Articles on this Report: 3 Displayed | Download in RIS Format
| Other project views: | All 92 publications | 21 publications in selected types | All 16 journal articles |
| Type | Citation | ||
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Steinemann A. Rethinking human health impact assessment. Environmental Impact Assessment Review 2000;20(6):627-645. |
R825758 (2000) R825758 (Final) |
not available |
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Zeng W, Beck MB. Development and evaluation of a mathematical model for the study of sediment-related water quality issues. Water Science and Technology 2001;43(7):47-54. |
R825758 (2000) R825758 (Final) |
not available |
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Zeng X-Q, Rasmussen TC. Characterization of Lake Lanier water quality using principal components and cluster analysis. Journal of Environmental Quality 2005;34(6):1980-1991. |
R825758 (2000) R825758 (Final) |
not available |
integrated assessment, control in ecosystems, environmental engineering. , Economic, Social, & Behavioral Science Research Program, Water, Scientific Discipline, RFA, Water & Watershed, decision-making, Economics & Decision Making, Biochemistry, Hydrology, Watersheds, Ecology and Ecosystems, Geochemistry, stakeholder feedback, water quality, ecosystem valuation, public policy, community-based research, ecology assessment models, ecological indicators, aquatic ecosystems, availability of water resources, lake ecosysyems, biogeochemical study, coefficient variations, Monte Carlo simulations, long term ecological integrity, water resources, microbial food web, urban watershed rehabilitation method
Relevant Websites:
http://hilbert.forestry.uga.edu/beck
Progress and Final Reports:
1998 Progress Report
1999 Progress Report
Original Abstract
Final Report