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321.
On measuring wealth: a case study on the state of Queensland   总被引:3,自引:0,他引:3  
In order for policy makers to plan effectively for sustainable development, there is a need for measures of welfare that consider changes in the natural capital stock. Current measures based on conventional national accounting are flawed because they are based solely on flow measures and do not account for environmental effects. In this paper, we use an expanded measure of wealth to estimate the value of natural capital for Queensland. The state's stock of natural capital is valued at A dollar 355.6 billion, of which non-timber forest resources account for 45.3%, ecosystem services 20.0%, and mineral resources 17.6%. This figure is a conservative estimate of the true value since some significant components such as the ecological and life-support functions of the environment are excluded. The estimates highlight the relative importance of different forms of natural capital and can be used to draw the attention of policymakers to the need to give adequate weight to the value of such services in decision-making processes.  相似文献   
322.
Polycyclic aromatic hydrocarbons (PAHs) have earned considerable attention due to their widespread environmental distribution and toxicity. In the environment, PAHs decompose by a variety of biotic and abiotic pathways. In both polar and nonpolar environments, phenanthrene (Phe, a common, three-ring PAH) is converted by sunlight to more polar products such as 9,10-phenanthrenequinone (PheQ) and subsequent oxidation products such as the corresponding open-ring dicarboxylic acid product. Biodegradation of phenanthrene also usually leads to oxidative metabolites, and eventually ends in mineralization. Our experimental objective was to investigate the photodegradation of phenanthrene and determine the effect of reaction products such as PheQ on microbial biodegradation of two- and three-ring PAHs. Abiotic experiments were performed to examine the photolytic breakdown of Phe; Phe was converted to PheQ, which catalyzed its own formation. In biodegradation experiments PheQ (0.04-4 mg/L) caused marked inhibition of naphthalene (Nap) biodegradation by a Burkholderia species; Phe did not. Only 20% of the naphthalene was degraded in the presence of PheQ compared with 75% in the control culture with no PheQ added. No PAH-degrading cultures were able to use PheQ as sole carbon source; however, the Phe-degrading enrichment culture dominated by a Sphingomonas species was able to degrade PheQ cometabolically in the presence of Phe. These results may explain why photooxidized phenanthrene-containing mixtures can resist biodegradation.  相似文献   
323.
This study quantified nonpoint source nitrogen (NPS‐N) sources and sinks across the 14,582 km2 Neuse River Basin (NRB) located in North Carolina, to provide tabular data summaries and graphic overlay products to support the development of management approaches to best achieve established N reduction goals. First, a remote sensor derived, land cover classification was performed to support modeling needs. Modeling efforts included the development of a mass balance model to quantify potential N sources and sinks, followed by a precipitation event driven hydrologic model to effectively transport excess N across the landscape to individual stream reaches to support subsequent labeling of transported N values corresponding to source origin. Results indicated that agricultural land contributed 55 percent of the total annual NPS‐N loadings, followed by forested land at 23 percent (background), and urban areas at 21 percent. Average annual N source contributions were quantified for agricultural (1.4 kg/ha), urban (1.2 kg/ha), and forested cover types (0.5 kg/ha). Nonpoint source‐N contributions were greatest during the winter (40 percent), followed by spring (32 percent), summer (28 percent), and fall (0.3 percent). Seasonal total N loadings shifted from urban dominated and forest dominated sources during the winter, to agricultural sources in the spring and summer. A quantitative assessment of the significant NRB land use activities indicated that high (greater than 70 percent impervious) and medium (greater than 35 percent impervious) density urban development were the greatest contributors of NPS‐N on a unit area basis (1.9 and 1.6 kg/ha/yr, respectively), followed by row crops and pasture/hay cover types (1.4 kg/ha/yr).  相似文献   
324.
In Massachusetts, the Charles River Watershed Association conducts a regular water quality monitoring and public notification program in the Charles River Basin during the recreational season to inform users of the river's health. This program has relied on laboratory analyses of river samples for fecal coliform bacteria levels, however, results are not available until at least 24 hours after sampling. To avoid the need for laboratory analyses, ordinary least squares (OLS) and logistic regression models were developed to predict fecal coliform bacteria concentrations and the probabilities of exceeding the Massachusetts secondary contact recreation standard for bacteria based on meteorological conditions and streamflow. The OLS models resulted in adjusted R2s ranging from 50 to 60 percent. An uncertainty analysis reveals that of the total variability of fecal coliform bacteria concentrations, 45 percent is explained by the OLS regression model, 15 percent is explained by both measurement and space sampling error, and 40 percent is explained by time sampling error. Higher accuracy in future bacteria forecasting models would likely result from reductions in laboratory measurement errors and improved sampling designs.  相似文献   
325.
ABSTRACT: Remote sensing offers an attractive alternative to conventional data collection employed in the estimation of certain hydrologic model parameters. In this investigation, the standard error of parameters estimated from Landsat data are examined. Relationships between the standard error and the size of the spatial-modeling units are developed that allow extending results to larger areas. Based upon the investigations conducted, a generalized model of the error relationships could not be developed.  相似文献   
326.
ABSTRACT: The objective of the study was to evaluate alternative land developments around New Hampshire lakes. Alternative development patterns, evaluated by their impacts on the lake area environment and area economy, included residential patterns, commercial patterns, and combinations of these two types. Phosphorus loading of the lake water was used as a proxy variable for changes in the lake water quality. Commercial developments yielded the highest revenues to the town and the local area. It also attracted the most lake users to the area as well as contributing the largest phosphorus loading in the lake waters. Residential developments, although contributing high revenues to the businessmen in the area, yielded less net income to the town. Phosphorus loading levels from residential developments were much lower than lake phosphorus loading by commercial developments.  相似文献   
327.
The Miami Conservancy District was organized shortly after the disastrous flood of March 1913 to provide flood protection to municipalities along the Great Miami River. The District system is a classic solution which was entirely locally financed and is now operated and maintained by special benefit assessments on 45,000 parcels of property, 9 cities and 5 counties.  相似文献   
328.
Headwater streams have a significant nexus or physical, chemical, and/or biological connection to downstream reaches. Generally, defined as 1st‐3rd order with ephemeral, intermittent, or perennial flow regimes, these streams account for a substantial portion of the total stream network particularly in mountainous terrain. Due to their often remote locations, small size, and large numbers, conducting field inventories of headwater streams is challenging. A means of estimating headwater stream location and extent according to flow regime type using publicly available spatial data is needed to simplify this complex process. Using field‐collected headwater point of origin data from three control watersheds, streams were characterized according to a set of spatial parameters related to topography, geology, and soils. These parameters were (1) compared to field‐collected point of origin data listed in three nearby Jurisdictional Determinations, (2) used to develop a geographic information system (GIS)‐based stream network for identifying ephemeral, intermittent, and perennial streams, and (3) applied to a larger watershed and compared to values obtained using the high‐resolution National Hydrography Dataset (NHD). The parameters drainage area and local valley slope were the most reliable predictors of flow regime type. Results showed the high‐resolution NHD identified no ephemeral streams and 9 and 65% fewer intermittent and perennial streams, respectively, than the GIS model.  相似文献   
329.
The aim of this investigation was to evaluate the influence of batch versus continuous flow on the removal efficiencies of chemical oxygen demand (COD), nitrogen (N) and total phosphorus (TP) in tropical subsurface flow constructed wetlands (SSF CW). The quantitative role of the higher aquatic plants in nutrient removal in these two operational modes was also investigated. Results indicated no significant difference (p > 0.05) in COD removal between batch and continuous flow modes for either the planted or unplanted treatments. Furthermore, the batch-loaded planted wetlands showed significantly (p < 0.05) higher ammonium removal efficiencies (95.2%) compared with the continuously fed systems (80.4%), most probably because the drain and fill batch mode presented systematically more oxidized environmental conditions. With respect to TP removal, for both planted and unplanted beds, there was significant enhancement (p < 0.05) in batch flow operation (69.6% for planted beds; 39.1% for unplanted beds) as compared to continuous flow operation (46.8% for planted beds; 25.5% for unplanted beds). In addition, at a 4-day hydraulic retention time (HRT), the presence of plants significantly enhanced both ammonia oxidation and TP removal in both batch and continuous modes of operation as compared to that for unplanted beds. An estimation of the quantitative role of aeration from drain and fill operation at a 4-day HRT, as compared to rhizosphere aeration by the higher aquatic plant, indicated that drain and fill operation might account for only less than half of the higher aquatic plant's quantitative contribution of oxygen (1.55 g O2 per m2 per day for batch flow versus 1.13 g O2 per m2 per day for continuous flow).  相似文献   
330.
Warner, Richard C., Carmen T. Agouridis, Page T. Vingralek, and Alex W. Fogle, 2010. Reclaimed Mineland Curve Number Response to Temporal Distribution of Rainfall. Journal of the American Water Resources Association (JAWRA) 46(4): 724-732. DOI: 10.1111/j.1752-1688.2010.00444.x Abstract: The curve number (CN) method is a common technique to estimate runoff volume, and it is widely used in coal mining operations such as those in the Appalachian region of Kentucky. However, very little CN data are available for watersheds disturbed by surface mining and then reclaimed using traditional techniques. Furthermore, as the CN method does not readily account for variations in infiltration rates due to varying rainfall distributions, the selection of a single CN value to encompass all temporal rainfall distributions could lead engineers to substantially under- or over-size water detention structures used in mining operations or other land uses such as development. Using rainfall and runoff data from a surface coal mine located in the Cumberland Plateau of eastern Kentucky, CNs were computed for conventionally reclaimed lands. The effects of temporal rainfall distributions on CNs was also examined by classifying storms as intense, steady, multi-interval intense, or multi-interval steady. Results indicate that CNs for such reclaimed lands ranged from 62 to 94 with a mean value of 85. Temporal rainfall distributions were also shown to significantly affect CN values with intense storms having significantly higher CNs than multi-interval storms. These results indicate that a period of recovery is present between rainfall bursts of a multi-interval storm that allows depressional storage and infiltration rates to rebound.  相似文献   
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