Evaluation of Ground‐Water and Surface‐Water Exchanges Using Streamflow Difference Analyses1

Abstract: In the karstic lower Flint River Basin, limestone fracturing, jointing, and subsequent dissolution have resulted in the development of extensive secondary permeability and created a system of major conduits that facilitate the exchange of water between the Upper Floridan aquifer and Flint River. Historical streamflow data from U.S. Geological Survey gaging stations located in Albany and Newton, Georgia, were used to quantify ground‐water and surface‐water exchanges within a 55.3 km section of the Flint River. Using data from 2001, we compared estimates of ground‐water flux using a time adjustment method to a water balance equation and found that these independent approaches yielded similar results. The associated error was relatively large during high streamflow when unsteady conditions prevail, but much lower during droughts. Flow reversals were identified by negative streamflow differences and verified with in situ data from temperature sensors placed inside large spring conduits. Long‐term (13 years) analysis showed negative streamflow differentials (i.e., a losing stream condition) coincided with high river stages and indicated that streamflow intrusion into the aquifer could potentially exceed 150 m³/s. Although frequent negative flow differentials were evident, the Flint River was typically a gaining stream and showed a large net increase in flow between the two gages when examined over the period 1989‐2003. Ground‐water contributions to this stream section averaged 2‐42 m³/s with a mean of 13 m³/s. The highest rate of ground‐water discharge to the Flint River occurred during the spring when regional ground‐water levels peaked following heavy winter and spring rains and corresponding rates of evapotranspiration were low. During periods of extreme drought, ground‐water contributions to the Flint River declined.     

Environmental biotechnology: A bioremediation perspective

The term environmental biotechnology has a certain air of modernity when in fact it has a long history of use, if one considers the underlying principles and not the appellation. However, as part of its complex meaning, there is a dynamic new definition and purpose in this discipline with regard to bioremediation. The ability to probe the environment at the molecular level with exquisite methods, to create a new awareness of fundamental biological processes therein, has created an important new paradigm in remediation engineering design and management. Further, biological lines of evidence made extremely robust through the merger of biotechnology and environmental science are poised to be incorporated into the very fabric of site evaluation and disposition at the regulatory level. At the operational level, the field of environmental biotechnology is driven by the “omics,” the common suffix for disciplines like genomics, proteomics, and metabolomics. An introduction to these elements of the process is followed by a review of how they are being used right now in a commercial framework, with the understanding that the entire process is still in the formative stages of its vast potential. © 2005 Wiley Periodicals, Inc.     

Perchlorate: Sources,uses, and occurrences in the environment

Perchlorate contamination of groundwater and soil continues to be a hot topic in many sectors, including industry, the federal Departments of Defense and Energy, regulators, and the general public. This article presents information on what is currently known regarding perchlorate uses, known and suspected naturally occurring versus anthropogenic perchlorate sources, and past and present manufacturing locations. It provides the reader with a baseline as well as background information to facilitate an understanding of perchlorate in the environment for the ultimate purpose of remediation. The article is based on research conducted by the Interstate Technology Regulatory Council for a forthcoming, more substantial perchlorate overview document scheduled for publication later in 2005. The document will include an overview of the chemical and discussions of remediation techniques and methods of analysis. © 2005 Wiley Periodicals, Inc.     

Science, Policy, and Stakeholders: Developing a Consensus Science Plan for Amchitka Island, Aleutians, Alaska

With the ending of the Cold War, the US Department of Energy is responsible for the remediation of radioactive waste and disposal of land no longer needed for nuclear material production or related national security missions. The task of characterizing the hazards and risks from radionuclides is necessary for assuring the protection of health of humans and the environment. This is a particularly daunting task for those sites that had underground testing of nuclear weapons, where the radioactive contamination is currently inaccessible. Herein we report on the development of a Science Plan to characterize the physical and biological marine environment around Amchitka Island in the Aleutian chain of Alaska, where three underground nuclear tests were conducted (1965–1971). Information on the ecology, geology, and current radionuclide levels in biota, water, and sediment is necessary for evaluating possible current contamination and to serve as a baseline for developing a plan to ensure human and ecosystem health in perpetuity. Other information required includes identifying the location of the salt water/fresh water interface where migration to the ocean might occur in the future and determining groundwater recharge balances, as well as assessing other physical/geological features of Amchitka near the test sites. The Science Plan is needed to address the confusing and conflicting information available to the public about radionuclide risks from underground nuclear blasts in the late 1960s and early 1970s, as well as the potential for volcanic or seismic activity to disrupt shot cavities or accelerate migration of radionuclides into the sea. Developing a Science Plan involved agreement among regulators and other stakeholders, assignment of the task to the Consortium for Risk Evaluation with Stakeholder Participation, and development of a consensus Science Plan that dealt with contentious scientific issues. Involvement of the regulators (State of Alaska), resource trustees (U S Fish and Wildlife Service), representatives of the Aleut and Pribilof Island communities, and other stakeholders was essential for plan development and approval, although this created tensions because of the different objectives of each group. The complicated process of developing a Science Plan involved iterations and interactions with multiple agencies and organizations, scientists in several disciplines, regulators, and the participation of Aleut people in their home communities, as well as the general public. The importance of including all parties in all phases of the development of the Science Plan was critical to its acceptance by a broad range of regulators, agencies, resource trustees, Aleutian/Pribilof communities, and other stakeholders.     

Social interactions and resource ownership in two private protected areas of Paraguay

This paper describes the results of field research to dissect how social interactions differ between two reserves in Paraguay having very different styles of governance. The two reserves were Mbaracayú Natural Forest Reserve (Reserva Natural del Bosque de Mbaracayú, RNBM) and San Rafael Managed Resource Reserve (Reserva de Recursos Manejados San Rafael, RRMSR). RNBM is a private reserve owned by a non-governmental organisation, while RRMSR is a publicly-managed reserve, albeit with a substantial degree of private land ownership. Both reserves are intended to protect Atlantic Forest, one of the five world biodiversity 'hotspots', and also one of the most highly threatened. Each reserve and its buffer zone comprises a set of stakeholders, including indigenous communities and farmers, and the paper explores the interactions between these and the management regime. Indeed, while the management regimes of the two reserves are different, one being highly top-down (RNBM) and the other more socially inclusive (RRMSR), the issues that they have to deal with are much the same. However, while both management regimes will readily acknowledge the need to address poverty, inequality appears to be a far more sensitive issue. Whereas this may be expected for the privately-owned RNBM it is perhaps more surprising in RRMSR even when allowing for the fact that much of the land in the latter is in private hands. It is argued that the origins of this sensitivity rest within the broader features of Paraguayan society, and the prevalence of private land ownership. Yet ironically, it is the inequality in land ownership that is perhaps the most significant threat to conservation in both reserves. Therefore, while reserve-level analyses can provide some insight into the driving forces at play in the interaction between conservation and sustainable management, larger scales may be necessary to gain a fuller appreciation of the dynamics operating at site level. Even in a society with a history of centralised control these dynamics may be surprising.     

EVALUATING HSPF IN AN ARID,URBANIZED WATERSHED1

ABSTRACT: The Hydrologic Simulation Program‐FORTRAN (HSPF) is a powerful time variable hydrologic model that has rarely been applied in arid environments. Here, the performance of HSPF in southern California was assessed, testing its ability to predict annual volume, daily average flow, and hourly flow. The model was parameterized with eight land use categories and physical watershed characteristics. It was calibrated using rainfall and measured flow over a five‐year period in a predominantly undeveloped watershed and it was validated using a subsequent 4‐year period. The process was repeated in a separate, predominantly urbanized watershed over the same time span. Annual volume predictions correlated well with measured flow in both the undeveloped and developed watersheds. Daily flow predictions correlated well with measured flow following rain events, but predictions were poor during extended dry weather periods in the developed watershed. This modeling difficulty during dry‐weather periods reflects the large influence of, and the poor accounting in the model for, artificially introduced water from human activities, such as landscape overwatering, that can be important sources of water in urbanized arid environments. Hourly flow predictions mistimed peak flows, reflecting spatial and temporal heterogeneity of rainfall within the watershed. Model correlation increased considerably when predictions were averaged over longer time periods, reaching an asymptote after an 11‐hour averaging window.     

Applicability of a Septic Tank/Engineered Wetland Coupled System in the Treatment and Recycling of Wastewater from a Small Community

A septic tank (ST)/engineered wetland coupled system used to treat and recycle wastewater from a small community in Dar es Salaam, Tanzania was monitored to assess its performance. The engineered wetland system (EWS) had two parallel units each with two serial beds packed with different sizes of media and vegetated differently. The larger-sized medium bed was upstream and was planted with Phragmites (reeds) and the smaller-sized medium bed was downstream and was planted with Typha (cattails). The ST/EWS coupled system was able to remove ammonia by an average of 60%, nitrate by 71%, sulfate by 55%, chemical oxygen demand by 91%, and fecal coliform as well as total coliform by almost 100%. The effluent from the ST/EWS coupled system is used for irrigation. Notably, users of the recycled irrigation water do not harbor any negative feelings about it. This study demonstrates that it is possible to treat and recycle domestic wastewater using ST/EWS coupled systems. The study also brings attention to the fact that an ST/EWS coupled system has operation and maintenance (O&M) needs that must be fulfilled for its effectiveness and acceptability. These include removal of unwanted weeds, harvesting of wetland plants when the EWS becomes unappealingly bushy, and routine repair.     

Variations in jail sentences and the probability of re-arrest for driving while intoxicated

OBJECTIVE: The probability of re-arrest for driving while intoxicated (DWI) is compared for four different groups of individuals classified by whether the individual was convicted and, if so, the type of sentence received. METHOD: Subsequent re-arrests for DWI were examined for all individuals whose index arrest for DWI had occurred between 1994 and 2001 in a county in New Mexico. The groups included (1) those convicted as a result of the index arrest and sentenced to a 28-day jail/treatment program (N (#)=(#) 2,703); (2) all those not convicted as a result of the index arrest (N = 709); (3) those who were convicted but not sentenced to jail (N = 1,047); and (4) those convicted and sentenced to jail (N = 1,290). RESULTS: Adjusting for covariates of BAC, number of prior arrests, ethnicity, age, and sex, the probability of not being re-arrested was greatest among those sentenced to the jail/treatment program (Group 1), next highest in the two groups convicted but not sentenced to jail/treatment (Groups 3 and 4), and lowest in the group that was not convicted (Group 2). Length of jail sentence among people convicted but not sentenced to the jail/treatment program was unrelated to the probability of re-arrest. CONCLUSION: Conviction for DWI, regardless of the sentence, appears to reduce the probability of re-arrest, and being sentenced to a multi-modal treatment/incarceration program further reduces the probability of re-arrest. However, the other types of sentences do not appear to differ in their impact on probability of re-arrest.     

Evolutionary divergence among lineages of the ocean sunfish family,Molidae (Tetraodontiformes)

Ocean sunfish, family Molidae, are enigmatic members of the epipelagic fauna of all tropical and temperate oceans. A study, begun in 1998, initially focused on the population genetics of Mola mola Linnaeus 1758 immediately indicated high levels of genetic divergence in the d-loop and cytochrome b mitochondrial genes. This preliminary effort was expanded to include Masturus lanceolatus Liénard 1840, Ranzania laevis Pennant 1776, and representative sequences of other Tetraodontiformes. Analysis of the sequence data confirms that there are two species in the genus Mola, Mola mola and M. ramsayi Giglioli 1883, with the latter presumed to be limited to the southern hemisphere. There is an indication of inter-ocean subdivision within both species originating 0.05–0.32 and 1.55–4.10 million years ago, respectively. Given limited sample sizes, however, the divergence estimates are minimums and the isolating mechanisms remain speculative. The systematic analysis provided strong support for the sister taxa relationship between genera Masturus and Mola and the basal position of the genus Ranzania within the family, as well as the sister group relationship of the Tetraodontiform families Tetraodontidae + Diodontidae to the Molidae.