Attenuation Coefficients for Water Quality Trading

Water quality trading has been proposed as a cost-effective approach for reducing nutrient loads through credit generation from agricultural or point source reductions sold to buyers facing costly options. We present a systematic approach to determine attenuation coefficients and their uncertainty. Using a process-based model, we determine attenuation with safety margins at many watersheds for total nitrogen (TN) and total phosphorus (TP) loads as they transport from point of load reduction to the credit buyer. TN and TP in-stream attenuation generally increases with decreasing mean river flow; smaller rivers in the modeled region of the Ohio River Basin had TN attenuation factors per km, including safety margins, of 0.19-1.6%, medium rivers of 0.14-1.2%, large rivers of 0.13-1.1%, and very large rivers of 0.04-0.42%. Attenuation in ditches transporting nutrients from farms to receiving rivers is 0.4%/km for TN, while for TP attenuation in ditches can be up to 2%/km. A 95 percentile safety margin of 30-40% for TN and 6-10% for TP, applied to the attenuation per km factors, was determined from the in-stream sensitivity of load reductions to watershed model parameters. For perspective, over 50 km a 1% per km factor would result in 50% attenuation = 2:1 trading ratio

Porównanie metod suszenia gazu ziemnego przechowywanego w podziemnych magazynach gazu

Underground storage reservoirs are widely used. Gas is stored at 7 to 20 MPa and 20 to 35°C. Gas is saturated by moisture during the storage period. However, distributed gas should meet certain conditions. To reach requested water content the following methods can be used: absorption to triethylenglycol (TEG), adsorption by solid desiccants and multistage expansion. Energy demand, advantages and disadvantages of methods are discussed on base of chemical engineering calculations and available information.Podziemne zbiornki gazu są szeroki stosowane. Gaz przechowuje się pod ciśnieniem od 7 do 20 MPa i w temperaturze od 20 do 35°C. Podczas przechowywania gaz jest nasycony wilgocią. Jednakże rozdzielany gaz powinien spełniać określone warunki. Aby uzyskać wymaganą zawartość wilgoci w gazie można zastosować następujące metody: absorpcję glikolem trietylenowym (TEG), absorpcję stałymi substancjami osuszającymi i wielostopniową ekspansję. Zapotrzebowanie energii, zalety i wady wymienionych metod z uwzględnieniem obliczeń procesowych oraz dostępnej informacji są omówione w artykule

Few-layer titanium trisulfide (TiS\u3csub\u3e3\u3c/sub\u3e) field-effect transistors

Titanium trisulfide (TiS3) is a promising layered semiconductor material. Several-mm-long TiS3 whiskers can be conveniently grown by the direct reaction of titanium and sulfur. In this study, we exfoliated these whiskers using the adhesive tape approach and fabricated few-layer TiS3 field-effect transistors (FETs). The TiS3 FETs showed an n-type electronic transport with roomtemperature field-effect mobilities of 18-24 cm2V-1s-1 and ON/OFF ratios up to 300. We demonstrate that TiS3 is compatible with the conventional atomic layer deposition (ALD) procedure for Al2O3. ALD of alumina on TiS3 FETs resulted in mobility increase up to 43 cm2V-1s-1, ON/OFF ratios up to 7000, and much improved subthreshold swing characteristics. This study shows that TiS3 is a competitive electronic material in the family of two-dimensional (2D) transition metal chalcogenides and can be considered for emerging device applications

Relationships between environmental governance and water quality in a growing metropolitan area of the Pacific Northwest, USA

We investigate relationships between environmental governance and water quality in two adjacent growing metropolitan areas in the western US. While the Portland, Oregon and Vancouver, Washington metro areas share many common biophysical characteristics, they have different land development histories and water governance structures, providing a unique opportunity for examining how differences in governance might affect environmental quality. We conceptualize possible linkages in which water quality influences governance directly, using monitoring efforts as a metric, and indirectly by using the change in the sale price of single-family residential properties. Governance may then influence water quality directly through riparian restoration resulting from monitoring results and indirectly through land use policy. We investigate evidence to substantiate these linkages. Our results showed that changes in monitoring regimes and land development patterns differed in response to differences in growth management policy and environmental governance systems. Our results also showed similarities in environmental quality responses to varying governance systems. For example, we found that sales prices responded positively to improved water quality (e.g., increases in DO and reductions in bacteria counts) in both cities. Furthermore, riparian restoration efforts improved over time for both cities, indicating the positive effect of governance on this land-based resource that may result in improved water quality. However, as of yet, there were no substantial differences across study areas in water temperature over time, despite an expansion of these urban areas of more than 20 % over 24 years. The mechanisms by which water quality was maintained was similar in the sense that both cities benefited from riparian restoration, but different in the sense that Portland benefited indirectly from land use policy. A combination of long-term legacy effects of land development, and a relatively short history of riparian restoration in both the Portland and Vancouver regions, may have masked any subtle differences between study areas. An alternative explanation is that both cities exhibited combinations of positive indirect and direct water quality governance that resulted in maintenance of water quality in the face of increased urban growth. These findings suggest that a much longer-term water quality monitoring effort is needed to identify the effectiveness of alternative land development and water governance policies

Residents' perception of flood risk and urban stream restoration using multi‐criteria decision analysis

This research examines how individual preferences for the major functions of stream restoration processes are associated with flood prevention and risk mitigation in Johnson Creek of Portland, Oregon, USA. We first reviewed a set of results from an analytical hierarchy process (AHP) model to rank the major stream restoration functions and compared citizens\u27 preferences for “flood prevention” using ordinary least squares regression. Our results show that the perceptions and interests of citizens may be centred on the inconvenience of everyday life arising from the previous flood events. Residents in the highly urbanized downstream regions showed a higher sensitivity to flooding than those living in the upper regions of the watershed. Community participation and annual incomes are positively related to flood risk perception in more developed downstream regions, while ecological or development goals associated with property protection are positively associated with higher flood risk perception in the less developed upper regions. Our findings of citizen perceptions can be adopted to help local government leaders and households mitigate flood risk while also achieving multiple benefits from stream restoration projects

The amenity value of English nature: a hedonic price approach

Using a hedonic property price approach,we estimate the amenity value associated with proximity to habitats, designated areas, domestic gardens and other natural amenities in England. There is a long tradition of studies looking at the effect of environmental amenities and disamenities on property prices. But, to our knowledge, this is the first nationwide study of the value of proximity to a large number of natural amenities in England. We analysed 1 million housing transactions over 1996–2008 and considered a large number of environmental characteristics. Results reveal that the effects of many of these environmental variables are highly statistically significant, and are quite large in economic magnitude. Gardens, green space and areas of water within the census ward all attract a considerable positive price premium. There is also a strong positive effect from freshwater and flood plain locations, broadleaved woodland, coniferous woodland and enclosed farmland. Increasing distance to natural amenities such as rivers, National Parks and National Trust sites is unambiguously associated with a fall in house prices. Our preferred regression specifications control for unobserved labour market and other geographical factors using Travel to Work Area fixed effects, and the estimates are fairly insensitive to changes in specification and sample. This provides some reassurance that the hedonic price results provide a useful representation of the values attached to proximity to environmental amenities in England. Overall, we conclude that the housing market in England reveals substantial amenity value attached to a number of habitats, designations, private gardens and local environmental amenities