Effects of Riparian Areas,Stream Order,and Land Use Disturbance on Watershed‐Scale Habitat Potential: An Ecohydrologic Approach to Policy1

Abstract: Spatio‐temporal linkages between hydrologic and ecologic dimensions of watersheds play a critical role in conservation policies. Habitat potential is influenced by variation along longitudinal and lateral gradients and land use disturbance. An assessment of these influences provides critical information for protecting watershed ecosystems and in making spatially explicit, conservation decisions. We use an ecohydrologic approach that focuses on interface between hydrological and ecological processes. This study focuses on changes in watershed habitat potentials along lateral (riparian), and longitudinal (stream order) dimensions and disturbance (land use). The habitat potentials were evaluated for amphibians, reptiles, mammals, and birds in the Westfield River Watershed of Massachusetts using geographic information systems and multivariate analysis. We use a polynomial model to study nonlinear effects using robust regression. Various spatial policies were modeled and evaluated for influence on species diversity. All habitat potentials showed a strong influence along spatial dimensions and disturbance. The habitat potential for all vertebrate groups studied decreased as the distance from the riparian zone increased. Headwaters and lower order subwatersheds had higher levels of species diversity compared to higher order subwatersheds. It was observed that locations with the least disturbance also had higher habitat potential. The study identifies three policy criteria that could be used to identify critical areas within a watershed to conserve habitat suitable for various species through management and restoration activities. A spatially variable policy that is based on stream order, riparian distance, and land use can be used to maximize watershed ecological benefits. Wider riparian zones with variable widths, protection of headwaters and lower order subwatersheds, and minimizing disturbance in riparian and headwater areas can be used in watershed policy. These management objectives could be achieved using targeted economic incentives, best management practices, zoning laws, and educational programs using a watershed perspective.     

RUNOFF EVENT IMPACTS ON A WATER SUPPLY RESERVOIR: SUSPENDED SEDIMENT LOADING, TURBID PLUME BEHAVIOR, AND SEDIMENT DEPOSITION1

Abstract: The impacts of runoff events on external suspended solids loading to Schoharie Reservoir, New York, and patterns of light scattering and sediment deposition in this reservoir are assessed. The assessment is based on monitoring of suspended solids concentrations in the reservoir's primary tributary, detailed vertical profiles of optical backscattering (a surrogate measure of light scattering) in the reservoir water column, and analysis of sediment trap collections, over a seven-month interval of high runoff. These impacts are reported to be tightly temporally coupled and strongly positively related to the magnitude of runoff events. The primary tributary entered the reservoir as a plunging inflow during runoff events, causing conspicuous subsurface peaks in light scattering, with vertical patterns that varied strongly for different events. Deposition quantified by near-bottom trap deployments is reported to be more representative than results from metalimnetic deployments that were generally within, rather than below, the turbid layers. Direct inputs of sediment, transported by density currents, are found to drive deposition, rather than resuspension/redeposition. More than 50 percent of the reported deposition occurred in less than 15 percent of the study period, associated with the four largest runoff events.     

Design of environmentally and socially conscious water metering tariffs for the UK

England is one of the few industrialised countries where water metering is not compulsory. Most households instead pay a fixed charge regardless of use. Yet water consumption is already at the limit of resources and beyond them in some regions. Despite the need to control demand, compulsory water metering has not been implemented largely because of concerns about the regressive impact on poorer households. This research analysed new data from Anglian Water on household water consumption and income to examine the distributional impacts of ten different hypothetical tariff designs. It was found that it was possible to design revenue-neutral metered tariffs that would cause only a small percentage of low-income households to lose and most to gain. With sensitive design, the social concerns about compulsory water metering can be dealt with.     

GROUPWISE MODELING STUDY OF BACTERIALLY IMPAIRED WATERSHEDS IN TEXAS: CLUSTERING ANALYSIS1

ABSTRACT: Under the Clean Water Act (CWA) program, the Texas Commission on Environmental Quality (TCEQ) listed 110 stream segments in the year 2000 with pathogenic bacteria impairment. A study was conducted to evaluate the probable sources of pollution and characterize the watersheds associated with these impaired water bodies. The primary aim of the study was to group the water bodies into clusters having similar watershed characteristics and to examine the possibility of studying them as a group by choosing models for total maximum daily load (TMDL) development based on their characteristics. This approach will help to identify possible sources and determine appropriate models and hence reduce the number of required TMDL studies. This in turn will help in reducing the effort required to restore the health of the impaired water bodies in Texas. The main characteristics considered for the classification of water bodies were land use distribution within the watershed, density of stream network, average distance of land of a particular use to the closest stream, household population, density of on‐site sewage facilities (OSSFs), bacterial loading from different types of farm animals and wildlife, and average climatic conditions. The climatic data and observed instream fecal coliform bacteria concentrations were analyzed to evaluate seasonal variability of instream water quality. The grouping of water bodies was carried out using the multivariate statistical techniques of factor analysis/principal component analysis, cluster analysis, and discriminant analysis. The multivariate statistical analysis resulted in six clusters of water bodies. The main factors that differentiated the clusters were found to be bacterial contribution from farm animals and wildlife, density of OSSFs, density of households connected to public sewers, and land use distribution.     

Fuel switching,gasoline price controls,and the leaded-unleaded gasoline price differential

The Environmental Protection Agency and others have opposed gasoline price decontrol, alleging a wider posted price differential between leaded and unleaded grades would result, inducing more motorists to switch illegally to leaded gasoline fouling catalytic converters and hence increasing air pollution. EPA's model must assume that only the unleaded price ceiling is binding. It is shown that the resulting excess demand is shifted to a close substitute: leaded gasoline. Hence, controls cause more consumption of leaded fuel in new cars (switching) and more pollution. Thus, decontrol would have a palliative effect, contrary to EPA's claim.     

Maternal environment and the expression of murine neural tube defects

The role that genetic and environmental factors play in triggering neural tube defects in the mouse mutant curly-tail (ct) were investigated by transplanting curly-tail blastocysts into the uterus of either curly-tail females or females of an unrelated A strain with a low natural incidence of abnormalities of the neural tube. The percentages of fetuses with neural tube defects were found to be similar in both groups. These results show that in curly-tail mice exencephaly and spina bifida are manifested independently of the maternal environment.     

Effects of self-esteem and gender on goal choice

The relationship between enduring or personality characteristics and goal choice has been of considerable theoretical, but little empirical interest in recent years. From an expectancy value perspective, we addressed the impact of self-esteem and gender on choice of goal difficulty level. As predicted, esteem and gender made significant contributions to the prediction of goal choice. The implications of these findings for future research in organizational settings, goal setting theory, and the relationship between goals and tasks are discussed.