INTERSTATE AND INTERNATIONAL COMPETITION FOR WATER RESOURCES1

ABSTRACT: Federal-state relations over the management and regulation of ground water resources have undergone a number of changes in recent years. There are a variety of reasons that the role of the federal government in ground water management may increase in the future. One important reason federal policymakers may become involved concerns the extent of competition for ground water resources that cross state and national borders. This article summarizes reasons that interstate and international competition for ground water resources may provide the impetus for federal intervention in ground water management and presents the results of a survey conducted to determine the extent of that competition.     

Density, velocity and flow relationships for closely packed crowds

Work undertaken to quantify the relationships between crowd velocities, flow rates and densities for uni-directional motion is reviewed. Most of the available data has been generated for underground stations in the UK; similar work for commuter stations in Japan is introduced and developed. Maximum observed flow rates from this work are compared with those suggested in the ‘Green Guide’ for the evacuation of sports grounds. The ‘Green Guide’ figures are higher than the maximum values obtained from the work reviewed.     

Total organic carbon analysis as a precursor to disinfection byproducts in potable water: oxidation technique considerations

In recent years, an increasing number of regulations and methodologies have begun to utilize total organic carbon (TOC) analysis for monitoring microbial contamination and/or disinfectant byproduct (DBP) precursors. This paper highlights some analytical differences and similarities between the two widely used TOC oxidation techniques: UV persulfate and high temperature combustion (HTC). Previous papers have come to different and sometimes contradictory conclusions on this subject. However, these studies either compared instruments with significantly different flow paths or TOC systems from different eras. Unlike previous studies, this paper compares two modern TOC analyzers with nearly identical flow paths for sample recovery, detection limits, and analysis of real world samples. On average, both persulfate and HTC oxidation yielded good recoveries for 10 hard to oxidize compounds and potable water samples from 5 different locations across the USA. In general, persulfate yielded more precise results because of its lower background response relative to sample response while HTC gave slightly higher results (roughly 2% to 3%) for surface water samples.     

Sustainable urban planning and the brownfield development process in the United Kingdom: Lessons from the Thames Gateway

Over recent decades urban and regional development agendas in the United Kingdom have become dominated by the discourses of sustainable development, holistic regeneration and community capacity-building. It is in this context that brownfield development has emerged as a core feature in strategies to regenerate urban areas. Bringing brownfields back into use tends to be, a priori, presented as a 'good thing' that will have broader economic, environmental and social benefits. This paper assesses the role that brownfield development plays in urban and regional policy agendas in the UK. It begins by identifying the rationales for, and concerns associated with, the brownfield development process in the UK, before discussing the trajectories of policy under the New Labour government since 1997. It argues that at present too much is expected from brownfield-led regeneration programmes and that wider benefits will only accrue if these programmes are embedded within a wider and more comprehensive set of development projects and policy agendas.     

COST EFFECTIVE ARSENIC REDUCTIONS IN PRIVATE WELL WATER IN MAINE1

ABSTRACT: This study was undertaken to investigate the cost effectiveness of selected arsenic avoidance methods. Annual costs of reverse osmosis (RO), activated alumina (AA), bottled water, and rented and purchased water coolers for various household sizes in Maine were compared. Relative ranking of systems shows that RO ($411 annually) is the most cost effective, followed by AA ($518) and one‐gallon jugs of water ($321 to $1,285), respectively, for households larger than one person. One‐gallon jugs ($321) followed by 2.5‐gallon jugs ($358) of water were found to be the most cost effective for households of one person or for households with arsenic III concentrations of 0.02 to 0.06 mg/L and arsenic V concentrations of 0.08 to 1.0 mg/L. Point‐of‐entry systems and water coolers were not found to be cost effective under any of the study's conditions. The research reported here will help states make more definitive treatment recommendations to households regarding the cost effectiveness of alternative treatment systems to reduce arsenic concentrations below 0.01 mg/L. While arsenic removal technologies are improving, which enhances removal rates and reduces costs, the major insights from this analysis appear to be reinforced by technological improvements.     

EVAPOTRANSPIRATION FROM FLORIDA PONDCYPRESS SWAMPS1

ABSTRACT: We measured diurnal changes in water levels in three swamps dominated by pondcypress trees (Taxodium distichum var. nuans) in central Florida for four years in order to obtain additional documentation of relatively low evapotranspiration (ET) rates. Two of these swamps were monitored for another three years after one of them was clearcut. Estimated annual ET from undisturbed cypress swamps varied from 38 cm/yr to 86 cm/yr, averaging 60 cm (not including interception). Faster ET rates may have been related to faster pondcypress growth rates, a greater proportion of hardwoods in the canopy, and clearcutting in the surrounding pine plantation. The average ET rate was considerably lower than ET rates that have been estimated for north Florida pine plantations. However, incorporating estimates of interception indicates that overall ET rates in pondcypress swamps may be only slightly lower than ET from pine plantations. ET decreased only 5 percent in one swamp after it was clearcut, indicating that this management practice is not likely to affect regional water balances.