A Retrospective Look at the Water Resource Management Policies in Nassau County,Long Island,New York1

Abstract: The residents of Nassau County Long Island, New York receive all of their potable drinking water from the Upper Glacial, Jameco/Magothy (Magothy), North Shore, and Lloyd aquifers. As the population of Nassau County grew from 1930 to 1970, the demand on the ground‐water resources also grew. However, no one was looking at the potential impact of withdrawing up to 180 mgd (7.9 m³/s) by over 50 independent water purveyors. Some coastal community wells on the north and south shores of Nassau County were being impacted by saltwater intrusion. The New York State Legislature formed a commission to look into the water resources in 1972. The commission projected extensive population growth and a corresponding increase in pumping resulting in a projected 93.5 to 123 mgd (4.1 to 5.5 m³/s) deficit by 2000. In 1986, the New York Legislature passed legislation to strengthen the well permit program and also establish a moratorium on new withdrawals from the Lloyd aquifer to protect the coastal community’s only remaining supply of drinking water. Over 30 years has passed since the New York Legislature made these population and pumping projections and it is time to take a look at the accuracy of the projections that led to the moratorium. United States Census data shows that the population of Nassau County did not increase but decreased from 1970 to 2000. Records show that pumping in Nassau County was relatively stable fluctuating between 170 and 200 mgd (7.5 to 8.8 m³/s) from 1970 to 2004, well below the projection of 242 to 321 mgd (10.6 to 14.1 m³/s). Therefore, the population and water demand never grew to projected values and the projected threat to the coastal communities has diminished. With a stable population and water demand, its time to take a fresh look at proactive ground‐water resource management in Nassau County. One example of proactive ground‐water management that is being considered in New Jersey where conditions are similar uses a ground‐water flow model to balance ground water withdrawals, an interconnection model to match supply with demand using available interconnections, and a hydraulic model to balance flow in water mains. New Jersey also conducted an interconnection study to look into how systems with excess capacity could be used to balance withdrawals in stressed aquifer areas with withdrawals in unstressed areas. Using these proactive ground‐water management tools, ground‐water extraction could be balanced across Nassau County to mitigate potential impacts from saltwater intrusion and provide most water purveyors with a redundant supply that could be used during water emergencies.     

Impacts of Multiple Stresses on Water Demand and Supply Across the Southeastern United States1

Abstract: Assessment of long‐term impacts of projected changes in climate, population, and land use and land cover on regional water resource is critical to the sustainable development of the southeastern United States. The objective of this study was to fully budget annual water availability for water supply (precipitation ? evapotranspiration + groundwater supply + return flow) and demand from commercial, domestic, industrial, irrigation, livestock, mining, and thermoelectric uses. The Water Supply Stress Index and Water Supply Stress Index Ratio were developed to evaluate water stress conditions over time and across the 666 eight‐digit Hydrologic Unit Code basins in the 13 southeastern states. Predictions from two Global Circulation Models (CGC1 and HadCM2Sul), one land use change model, and one human population model, were integrated to project future water supply stress in 2020. We found that population increase greatly stressed water supply in metropolitan areas located in the Piedmont region and Florida. Predicted land use and land cover changes will have little effect on water quantity and water supply‐water demand relationship. In contrast, climate changes had the most pronounced effects on regional water supply and demand, especially in western Texas where water stress was historically highest in the study region. The simulation system developed by this study is useful for water resource planners to address water shortage problems such as those experienced during 2007 in the study region. Future studies should focus on refining the water supply term to include flow exchanges between watersheds and constraints of water quality and environmental flows to water availability for human use.     

Using opportunistic green macroalgae as indicators of nitrogen supply and sources to estuaries.

Nutrient inputs to estuaries are increasing worldwide, and anthropogenic contributions are increasingly complex and difficult to distinguish. Measurement of integrated effects of salinity and nutrient changes simultaneously can help ascertain whether N sources of similar magnitude and stable isotope (sigma15N) signatures are river dominated. We used Enteromorpha spp., an opportunistic macroalga, to obtain integrated measures of salinity, nutrient supply, and nutrient source in estuaries. We outplanted cultured algae in the field along spatial gradients within three southern California estuaries for 24 hours in wet and dry seasons. Tissue was analyzed for potassium (K+) to measure osmoregulatory changes, total nitrogen to examine changes in nutrient supply, and sigma15N to assess nutrient sources. Discrete measures of water salinity correlated with tissue K+ content; however, there was significant variability in the relationship, suggesting that the algae were subject to considerable variation in salinity over a tidal cycle. Tissue total N was not always related to snapshot measures of water column dissolved inorganic nitrogen (DIN), suggesting that integrated measures may be better at capturing the temporal and spatial complexity of nutrient availability. The combination of tissue K+, total N, and sigma15N measures revealed that inflowing rivers delivered N from watershed sources to Mugu Lagoon and Carpinteria Salt Marsh, while both the inflowing river and a mid estuary source were important sources of high sigma15N N in Upper Newport Bay. These experiments revealed complex patterns of supply and sources of N and demonstrate the usefulness of macroalgal indicators over water sampling to detect these patterns.     

Social features of energy production and use in Brazil: Goals for a sustainable energy future

This paper focuses on the social features of ene rgy production and use in Brazil and discusses the role of the energy policy goals of accessibility, affordability and acceptability in defining a sustainable energy future for the country. The major findings are that social inequalities in Brazil regarding energy use continue to be substantial and important. This can be explained by the fact that, although recent decades have seen significant improvements in energy accessibility all over the country, much more needs to be done to provide affordable, and socially acceptable modern energy carriers to all socio‐economic groups in all regions.     

The use of Monte Carlo simulation techniques to predict population blood lead levels

Effective management of the risks posed by lead depends on an understanding of the relationship between exposure (the presence and accessibility of lead in the environment) and dose (blood lead levels). Our paper begins by outlining the type of information most valuable to a decision maker addressing the lead problem. A useful exposure-dose characterisation must address multiple contamination sources simultaneously, provide estimates of the number of people with blood lead levels exceeding critical thresholds, and assess the influence of modifying factors (e.g. the soil and dust ingestion rate) on population blood lead variability. We describe a pilot effort to develop an urban setting lead exposure-dose model, and use this model to compare three approaches for generating model input quantities: (1) worst-case estimates, (2) central estimates and (3) Monte Carlo simulation. Using the criteria outlined above, we find that the Monte Carlo technique provides the most useful model output. We describe the population blood lead level distribution generated by the model, as well as the relative influence of environmental and behavioural factors on the variability of the population distribution. Finally, we assess the impact of parameter uncertainty on the model output, and contend this type of information can help identify areas in which further empirical study would be most valuable.     

Practical Policy Applications of Uncertainty Analysis for National Greenhouse Gas Inventories

International policy makers and climate researchers use greenhouse gas emissions inventory estimates in a variety of ways. Because of the varied uses of the inventory data, as well as the high uncertainty surrounding some of the source category estimates, considerable effort has been devoted to understanding the causes and magnitude of uncertainty in national emissions inventories. In this paper, we focus on two aspects of the rationale for quantifying uncertainty: (1) the possible uses of the quantified uncertainty estimates for policy (e.g., as a means of adjusting inventories used to determine compliance with international commitments); and (2) the direct benefits of the process of investigating uncertainties in terms of improving inventory quality. We find that there are particular characteristics that an inventory uncertainty estimate should have if it is to be used for policy purposes: (1) it should be comparable across countries; (2) it should be relatively objective, or at least subject to review and verification; (3) it should not be subject to gaming by countries acting in their own self-interest; (4) it should be administratively feasible to estimate and use; (5) the quality of the uncertainty estimate should be high enough to warrant the additional compliance costs that its use in an adjustment factor may impose on countries; and (6) it should attempt to address all types of inventory uncertainty. Currently, inventory uncertainty estimates for national greenhouse gas inventories do not have these characteristics. For example, the information used to develop quantitative uncertainty estimates for national inventories is often based on expert judgments, which are, by definition, subjective rather than objective, and therefore difficult to review and compare. Further, the practical design of a potential factor to adjust inventory estimates using uncertainty estimates would require policy makers to (1) identify clear environmental goals; (2) define these goals precisely in terms of relationships among important variables (such as emissions estimate, commitment level, or statistical confidence); and (3) develop a quantifiable adjustment mechanism that reflects these environmental goals. We recommend that countries implement an investigation-focused (i.e., qualitative) uncertainty analysis that will (1) provide the type of information necessary to develop more substantive, and potentially useful, quantitative uncertainty estimates-regardless of whether those quantitative estimates are used for policy purposes; and (2) provide information needed to understand the likely causes of uncertainty in inventory data and thereby point to ways to improve inventory quality (i.e., accuracy, transparency, completeness, and consistency).