USABILITY ASSESSMENTS FOR HYDROLOGIC FORECASTING DSS1

ABSTRACT: Usability assessments were used to obtain feedback on the development of a flood forecasting decision support system. The feedback was used to guide design of system functionality, interface, training, implementation, and operations. The usability process was user focused and was dependent upon implementation of a prototype system in an operational setting. This paper describes concepts and methods applied to collect reflective and objective data on DSS components and information outputs. The general structure of the usability assessments is discussed and results of assessments are summarized.     

Evaluating regional sustainable development: Approaches,methods and the politics of analysis

One of the by-products of the culture of targets, performance and assessment, is the introduction of uniform methods for the evaluation of the success of policy interventions. Such an approach has been applied to attempts to evaluate regional sustainable development, often with unsatisfactory results. This paper reviews some of the fundamental requirements for the evaluation of regional sustainable development and provides research evidence that indicates the need for procedural and institutional innovation. The evidence in support of innovation reflects the need for assessment procedures and methods to be tailored-to-fit the environmental, social and economic conditions obtaining in an individual region. An additional consideration in analysing the evaluation of regional sustainable development is the extent of socio-political influence over the choice of procedures and methodologies.     

Effects of water depth and litter accumulation on morpho-ecological adaptations of Eleocharis sphacelata

The morpho-ecological adaptations of Eleocharis sphacelata in response to water depth and the sequential effects of resultant differences in deep water conditions on the long term population dynamics were investigated based on the observations carried out in three stable homogeneous populations in Goulburn and Ourimbah, New South Wales, Australia from August 2003 to May 2005. The deep water populations attained a higher harvestable shoot biomass and a lower rhizome biomass with increased growth in root structure thus significantly enhancing the nutrient uptake rates leading to a higher accumulation of shoot bound macronutrients. However, the accretion of excessive amounts of autogenous shoot litter coupled with slower decomposition rates under anaerobic conditions in the two deep water populations led to higher nutrient enrichment in sediments and overlying water column causing subsequent eutrophication with signs of growth inhibition including typical stress symptoms like stunted growth and chlorotic shoots. The shallow water population that intermittently experienced alternative inundation-drawdown pattern depicted an unaffected continuation of seasonal growth affirming that strict water regime management practices coupled with timely mowing or the removal of accumulating litter are necessary to ensure long-term survival of healthy E. sphacelata stands when it is used in applications where deep water conditions prevail.     

Assessing Potential Removal of Low-Head Dams in Urban Settings: An Example from the Ottawa River,NW Ohio

This is a study of the scientific component of an effort to restore an urban river by removing a low-head dam. The Secor Dam is owned by a local government entity near Toledo, Ohio. The proposed removal of the last structure impeding flow on the Ottawa River has broad appeal, but the owner is concerned about liability issues, particularly potential changes to the flood regime, the presence of contaminated sediments behind the dam, and possible downstream transport of reservoir sediments. Assessing sediment contamination involved sediment sampling and analysis of trace metals and organic contaminants. Forecasting sediment transport involved field methods to determine the volume and textural properties of reservoir and upstream sediment and calculations to determine the fate of reservoir sediments. Forecasting changes in the flood regime involved HEC-RAS hydrological models to determine before and after dam removal flood scenarios using LiDAR data imported into an ArcGIS database. The resulting assessment found potential sediment contamination to be minor, and modeling showed that the removal of the dam would have minimal impacts on sediment transport and flood hazards. Based on the assessment, the removal of the dam has been approved by its owners.     

Wintertime vertical variations in particulate matter (PM) and precursor concentrations in the San Joaquin Valley during the California Regional Coarse PM/Fine PM Air Quality Study

Air quality monitoring was conducted at a rural site with a tower in the middle of California's San Joaquin Valley (SJV) and at elevated sites in the foothills and mountains surrounding the SJV for the California Regional PM10/ PM2.5 Air Quality Study. Measurements at the surface and n a tower at 90 m were collected in Angiola, CA, from December 2000 through February 2001 and included hourly black carbon (BC), particle counts from optical particle counters, nitric oxide, ozone, temperature, relative humidity, wind speed, and direction. Boundary site measurements were made primarily using 24-hr integrated particulate matter (PM) samples. These measurements were used to understand the vertical variations of PM and PM precursors, the effect of stratification in the winter on concentrations and chemistry aloft and at the surface, and the impact of aloft-versus-surface transport on PM concentrations. Vertical variations of concentrations differed among individual species. The stratification may be important to atmospheric chemistry processes, particularly nighttime nitrate formation aloft, because NO2 appeared to be oxidized by ozone in the stratified aloft layer. Additionally, increases in accumulation-mode particle concentrations in the aloft layer during a fine PM (PM2.5) episode corresponded with increases in aloft nitrate, demonstrating the likelihood of an aloft nighttime nitrate formation mechanism. Evidence of local transport at the surface and regional transport aloft was found; transport processes also varied among the species. The distribution of BC appeared to be regional, and BC was often uniformly mixed vertically. Overall, the combination of time-resolved tower and surface measurements provided important insight into PM stratification, formation, and transport.     

The effect of silica on the degradation of organohalides in granular iron columns

Dissolved silica species are naturally occurring, ubiquitous groundwater constituents with corrosion-inhibiting properties. Their influence on the performance and longevity of iron-based permeable reactive barriers for treatment of organohalides was investigated through long-term column studies using Connelly iron as the reactive medium. Addition of dissolved silica (0.5 mM) to the column feed solution led to a reduction in iron reactivity of 65% for trichloroethylene (TCE), 74% for 1,1,2-trichloroethane (1,1,2-TCA), and 93% for 1,1,1-trichloroethane (1,1,1-TCA), compared to columns operated under silica-free conditions. Even though silica adsorption was a gradual process, the inhibitory effect was evident within the first week, with subsequent decreases in reactivity over 288 days being relatively minor. Lower concentrations of dissolved silica species (0.2 mM) led to a lesser decrease (70%) in iron reactivity toward 1,1,1-TCA. The presence of dissolved silica species produced a shift in TCE product distribution toward the more highly chlorinated product cis-dichloroethylene (cis-DCE), although it did not appear to alter products originating from the trichloroethanes. The major corrosion products identified were magnetite (Fe3O4) or maghemite (gamma-Fe2O3) and carbonate green rust ([Fe4(2+)Fe(2)3+(OH)12][CO(3).2H2O]). Iron carbonate hydroxide (Fe(II)1.8Fe(III)0.2(OH)2.2CO3) was only found in the silica-free column, indicating that silica may hinder its formation. A comparison with columns operated under the same conditions, but using Master Builder iron as the reactive matrix, showed that Connelly iron is initially less reactive, but performs better than Master Builder iron over 288 days.     

Nature and nurture: Environmental isotope story of the River Rhine

The total dissolved load of the Rhine river increases downstream due to the combined impact of natural and pollution loads. The natural background, controlled by geology, is soon swamped by pollution, particularly from salt and coal mining activities in Alsace and the Ruhr area. The Rhine is also a net source of CO₂ from oxidation of excess organic productivity that is fuelled by nutrient pollution, a problem even more serious for some of its tributaries.Also Derry/Rust Research Group, Ottawa-Carleton Geoscience Center, University of Ottawa, Ottawa, Canada KIN 6N5