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1.
ABSTRACT: This paper presents a method for determining locations of observation wells to be used in conducting pumping tests in unconfined aquifers. Sensitivity coefficients, the distribution of relative errors, and the correlation coefficients between four aquifer parameters (horizontal and vertical hydraulic conductivities Kr and Kz, storage coefficient S, and specific yield Sy) are used as the criteria for the design of observation well networks and the interpretation of pumping tests. The contours of the relative errors over a vertical profile are very useful in selecting the “best” location of an observation well. Results from theoretical analyses suggest that a wide range of locations is suitable for the determination of Kr and that good locations for the determination of Kz and S may be poorly suited for the determination of Sy. Consideration must be given to the position and lengths of the pumping well screen in the selection of observation well locations. For a given location, the quality of test data can be improved by using high pumping rates and frequent sampling of drawdowns. We found that a minimum of two and preferably three observation locations are needed along a given transect. Results of the four parameters from a single well analysis may contain higher uncertainties. However, composite analyses of multiple observation wells can reduce the correlation between the four aquifer parameters, particularly between Kr and Sy, thus, improving the quality of parameter estimation. Results from two pumping tests conducted at sites located in Nebraska were examined with regard to the proposed methodology.  相似文献   

2.
This paper analyses patterns in beliefs about the implementation of wind power as part of a geographical comparison of onshore wind power developments in the Netherlands, North-Rhine Westphalia and England. Q methodology is applied, in order to systematically compare the patterns in stakeholder views on the institutional conditions and changes in the domains of energy policy, spatial planning and environmental policy. Three factors represent support for wind power implementation from fundamentally different perspectives. The fourth perspective is critical opposed to wind power developments as well as critical to the manner in which wind projects are proposed, planned and implemented. These four perspectives exist across the geographical cases; however, some perspectives are prominent in one case and marginal in another. This relates to different legacies and varying implementation achievements in the three cases. The analysis shows that an approach that focuses on implementing as much wind power as possible, relying on technocratic reasoning and hierarchical policies is in practice the least successful, whereas collaborative perspectives with more emphasis on local issues and less on the interests of the conventional energy sector were particularly dominant in the most successful case, North-Rhine Westphalia.  相似文献   

3.
Effect of land cover data on nitrous oxide inventory in fen meadows   总被引:1,自引:0,他引:1  
Landscape representations based on land cover databases differ significantly from the real landscape. Using a land cover database with high uncertainty as input for emission inventory analyses can cause propagation of systematic and random errors. The objective of this study was to analyze how different land cover representations introduce systematic errors into the results of regional N2O emission inventories. Surface areas of grassland, ditches, and ditch banks were estimated for two polders in the Dutch fen meadow landscape using five land cover representations: four commonly used databases and a detailed field map, which most closely resembles the real landscape. These estimated surface areas were scaled up to the Dutch western fen meadow landscape. Based on the estimated surface areas agricultural N2O emissions were estimated using different inventory techniques. All four common databases overestimated the grassland area when compared to the field map. This caused a considerable overestimation of agricultural N2O emissions, ranging from 9% for more detailed databases to 11% for the coarsest database. The effect of poor land cover representation was larger for an inventory method based on a process model than for inventory methods based on simple emission factors. Although the effect of errors in land cover representations may be small compared to the effect of uncertainties in emission factors, these effects are systematic (i.e., cause bias) and do not cancel out by spatial upscaling. Moreover, bias in land cover representations can be quantified or reduced by careful selection of the land cover database.  相似文献   

4.
Tools for assisting human navigation, especially in-vehicle systems, have been extensively investigated. However, few studies have explored the design of speech-based over-the-phone guidance systems. This study examined the effect of landmarks' use and the effect of landmarks’ frames of reference in route instructions on navigation efficiency during map navigation tasks and satisfaction. Twenty-seven participants performed map navigation tasks using a simulated speech navigation system in three experimental conditions: instructions containing no landmarks, instructions containing landmarks located without reference to either the traveler’s body or the surrounding environment, and instructions containing landmarks located with respect to the traveler’s body. Navigation performances on maps were higher and landmarks enable participants to make fewer directional errors and find their routes more efficiently. Satisfaction levels and navigation performances were lower when instructions did not contain any landmarks. Landmarks’ frames of reference shifting turned out to be different between human-human situations previously used and human-computer situations used here.  相似文献   

5.
6.
This paper develops a GIS-based integrated approach to risk assessment in natural hazards, with reference to bushfires. The challenges for undertaking this approach have three components: data integration, risk assessment tasks, and risk decision-making. First, data integration in GIS is a fundamental step for subsequent risk assessment tasks and risk decision-making. A series of spatial data integration issues within GIS such as geographical scales and data models are addressed. Particularly, the integration of both physical environmental data and socioeconomic data is examined with an example linking remotely sensed data and areal census data in GIS. Second, specific risk assessment tasks, such as hazard behavior simulation and vulnerability assessment, should be undertaken in order to understand complex hazard risks and provide support for risk decision-making. For risk assessment tasks involving heterogeneous data sources, the selection of spatial analysis units is important. Third, risk decision-making concerns spatial preferences and/or patterns, and a multicriteria evaluation (MCE)-GIS typology for risk decision-making is presented that incorporates three perspectives: spatial data types, data models, and methods development. Both conventional MCE methods and artificial intelligence-based methods with GIS are identified to facilitate spatial risk decision-making in a rational and interpretable way. Finally, the paper concludes that the integrated approach can be used to assist risk management of natural hazards, in theory and in practice.  相似文献   

7.
Models of carbon storage in softwood and hardwood trees and forest soils and its emission from timber products and waste are developed and integrated with data on storage benefits to yield estimates of the value of the net carbon flux generated by afforestation. The long-term nature of the processes under consideration and the impact of varying the discount rate are explicitly incorporated within the model. A geographical information system (GIS) is used to apply carbon sequestration models to data on tree growth and soil type distribution for a large study area (the entire country of Wales). The major findings are: (1) all three elements under analysis (carbon sequestration in livewood, release from different products and waste, and storage or emission from soils) play a vital role in determining overall carbon flux; (2) woodland management has a substantial impact upon carbon storage in livewood however the choice of discount rate exerts the largest overall influence upon estimated carbon flux values; (3) timber growth rates (yield class) also have a major impact upon values; (4) tree species does affect storage values, however this is less important than the other factors listed above; (5) non-peat soils generally sequester relatively low levels of carbon. Planting upon peat soils can result in very substantial emissions of carbon which exceed the level of storage in livewood.The GIS is used to produce valuation maps which can be readily incorporated within cost-benefit analyses regarding optimal locations for conversion of land into forestry.  相似文献   

8.
This paper analyses regulatory responses to rapid intensification of the use of drones/remotely piloted aircraft (RPA) in the context of wildlife protection. Benefits and disadvantages of the technology to wildlife are examined, before three key limitations in policy and law are identified: failure to address wildlife disturbance in RPA regulation; reliance upon insufficiently comprehensive existing wildlife protection legislation to manage disturbance effects; and limited species-specific research on disturbance. A New Zealand case study further reveals an inconsistent regulatory approach struggling to keep pace with innovation, inadequate regulatory capture of environmental effects due to exemption as “aircraft”, and no recognition that specific geographical locations, such as coastal areas, distinguished by recreational pressures and high numbers of threatened species require special consideration. Recommendations include acknowledging the impact on wildlife in policy, gap analysis of legal arrangements for protection from disturbance (including airspace), and adoption of minimum approach distances to threatened species.  相似文献   

9.
Abstract:  Data interpretation and visualization software tools with geostatistical capabilities were adapted, customized, and tested to assist the Chesapeake Bay Program in improving its water‐quality modeling protocols. Tools were required to interpolate, map, and visualize three‐dimensional (3D) water‐quality data, with the capability to determine estimation errors. Components of the software, originally developed for ground‐water modeling, were customized for application in estuaries. Additional software components were developed for retrieval, and for pre‐ and post‐ processing of data. The Chesapeake Bay Program uses the 3D mapped data for input to the Bay water‐quality model that projects the future health of the Bay and its tidal tributary system. In determining water‐quality attainment criteria, 3D kriging estimation errors are needed as a statistical measure of uncertainty. Furthermore, given the high cost of installing and operating new monitoring stations, geostatistical techniques can assist the Chesapeake Bay Program in the identification of suitable data collection locations. Following the evaluation, selection, and development of the software components phase, 3D ordinary kriging techniques with directional semi‐variograms to account for anisotropy were successfully demonstrated for mapping 3D fixed station water‐quality data, such as dissolved oxygen and salinity. Additionally, an improved delineation tool was implemented to simulate the upper and lower pycnocline boundary surfaces allowing the segregation of the interpolated 3D data into three separate zones for a better characterization of the pycnocline layer.  相似文献   

10.
This study examined the relationships between four standardized measures of spatial ability—the Embedded Figures Test (EFT), the Mental Rotations Test (MRT), the Differential Aptitude Spatial Relations subtest (DAT), and the Building Memory Test (BMT)—and two measures of environmental knowledge. Three hundred and fifty-three college undergraduates were administered the EFT, MRT, DAT, BMT and two measures of environmental knowledge-a landmark location (LM) and route knowledge (RK) task. The two environmental knowledge tasks were based on a slide-simulated walk through an unfamiliar urban environment. A principal components analysis of the above six measures produced two factors; one consisting of the four spatial ability tests, and the other the two environmental knowledge tasks. The correlation between the two factors was 0·37, indicating that the spatial ability factor accounted for 13·69% of the variance in the environmental knowledge factor.  相似文献   

11.
12.
Groundwater exchanges with most lakes are rarely quantified because there are many technical challenges to quantification. We investigated a lakebed mapping approach to infer the relative areas of groundwater exchange in 12 prairie shallow lakes and five Laurentian mixed forest shallow lakes in Minnesota, USA in 2011. We used a relatively common approach (seepage meters) to provide baseline information on the magnitude and direction of flow at four locations in each lake. To expand from point measurements to the whole‐lake scale, we explored use of specific conductivity as a cheaper and more time efficient proxy for groundwater discharge to lakes. We validated the approach at near shore stations in each lake where seepage meter measurements and specific conductivity surveys overlapped. Specific conductivity surveys provided a similar assessment of groundwater discharge compared to seepage meters for 50% of the lake‐sampling period combinations. The lakebed mapping approach, when validated for a lake with a limited number of seepage meter (or alternative methods) measurements, offers the advantages of being more time and labor efficient over the use of a similar number of seepage meter monitoring locations; seepage meters (or piezometers, for example) are costlier in terms of equipment and labor, even for single‐lake studies. We show the combined approach could provide useful baselines for understanding and mapping groundwater exchange in shallow lakes.  相似文献   

13.
The climate change literature emphasises the importance of geographical understanding for guiding adaptation, in which “place” perspectives are particularly significant. After “scale”, the term “place” within the climate change adaptation literature is most often implicitly used in reference to a delineated and localised region, such as place-based risk assessment or place-based adaptation planning. Here, we use a case study of the Australian island-state of Tasmania to demonstrate the importance and particularity of place in the formation of climate change adaptation issues, problem definition and framing, and the dynamics of knowledge and praxis development across a range of research and industry sectors. We describe the significance of the place Tasmania with regard to its geographical location; its portrayal as an island place; and its cultural meaning and relations. Through a synthesis of climate change adaptation research, policy literature and engagement with researchers and stakeholders, we identify three emergent thematic place characterisations of Tasmania. We find that these characterisations have contributed directly or indirectly to the: initiation and extent of research and practical activities; the framing of adaptation issues and perspectives on potential adaptation responses in different sectors including the marine biodiversity and resources sector, small business and human health sectors. Exposing these influences is essential for focusing future adaptation activities, including research, planning, investment and practice, in Tasmania and other locations where place is a central issue.  相似文献   

14.
An inventory was conducted to assess the number, type, spatial distribution, and costs of microbiological monitoring programs in southern California marine waters from Point Conception to the US/Mexico International Border. The location of each sampling site was determined using global positioning system (GPS), and estimates of geographic coverage were determined using geographic information system (GIS) techniques. Twenty-one programs conducted 87,007 tests annually at 576 sites in the study area. The largest number of sites was sampled in Orange County, whereas the largest number of analyses was performed in Los Angeles County because monitoring programs in this area focused on daily monitoring. Fifteen of the 21 programs were managed by National Pollutant Discharge Elimination System (NPDES) permitted sewage effluent dischargers who sampled both offshore and shoreline waters and typically tested for three indicator bacteria (total coliform, fecal coliform, and enterococcus). Their combined efforts comprised 82% of all of the microbiological indicator analyses conducted on an annual basis. Five of the remaining monitoring organizations were public health agencies, which typically focus their efforts on testing only total coliforms. Laboratory methodology also varied considerably, with NPDES permittees predominantly utilizing membrane filtration while public health agencies generally used multiple tube fermentation or premanufactured test kits. Nearly three quarters of all the effort expended in southern California occurred along the shoreline as opposed to offshore locations. Two thirds of this shoreline effort was focused on high-use sandy beaches and in proximity to perennial freshwater outlets (storm drains and creeks). Most sampling occurred at a set of fixed sites that were revisited frequently, but only represented about 7% of the total shoreline. We estimated that roughly $3 million is spent annually on monitoring bathing water quality in southern California, exceeding that spent in any other part of the country.  相似文献   

15.
River managers are tasked with meeting both ecological and human needs. In the Puget Sound lowland, riparian management often includes placing or allowing the presence of large wood to stabilize riverbanks and enhance salmon habitat. Although this practice benefits humans by protecting infrastructure and natural resources, it is unclear how such practices interact with an additional human interest, recreation. Furthermore, we were unable to find studies that describe how an agency can go about researching the interaction between recreation and large wood management practices. This study tested methods for describing and estimating the number of river floaters, where they float in relationship to river projects, the risks they take while floating, and their perceptions of large wood in the river. Selecting a high-use suburban river in Washington State, we used riverside observations, interviews, and an infrared counter to gather data in the summer of 2010. Statistical analyses provided general characteristics of users, trends in engaging in risky behaviors, and estimates of use for the entire season and on the busiest day. Data mapping with GIS presented the density of use along the river and frequency of use of specific float routes. Finally, qualitative analysis of interviews clarified floaters' perspectives of large wood. To address the multiple mandates of river managers, it is important to understand recreation users, the factors that could be putting them at risk, and how the actual users perceive large wood in the river. This study demonstrates methods for scientifically gathering such information and applying it when making riparian management decisions.  相似文献   

16.
The environmental sciences/studies movement, with more than 1000 programs at colleges and universities in the United States and Canada, is unified by a common interest??ameliorating environmental problems through empirical enquiry and analytic judgment. Unfortunately, environmental programs have struggled in their efforts to integrate knowledge across disciplines and educate students to become sound problem solvers and leaders. We examine the environmental program movement as a policy problem, looking at overall goals, mapping trends in relation to those goals, identifying the underlying factors contributing to trends, and projecting the future. We argue that despite its shared common interest, the environmental program movement is disparate and fragmented by goal ambiguity, positivistic disciplinary approaches, and poorly rationalized curricula, pedagogies, and educational philosophies. We discuss these challenges and the nature of the changes that are needed in order to overcome them. In a subsequent article (Part 2) we propose specific strategies for improvement.  相似文献   

17.
Kinzel, Paul J., Carl J. Legleiter, and Jonathan M. Nelson, 2012. Mapping River Bathymetry with a Small Footprint Green LiDAR: Applications and Challenges. Journal of the American Water Resources Association (JAWRA) 1‐22. DOI: 10.1111/jawr.12008 Abstract: Airborne bathymetric Light Detection And Ranging (LiDAR) systems designed for coastal and marine surveys are increasingly sought after for high‐resolution mapping of fluvial systems. To evaluate the potential utility of bathymetric LiDAR for applications of this kind, we compared detailed surveys collected using wading and sonar techniques with measurements from the United States Geological Survey’s hybrid topographic/bathymetric Experimental Advanced Airborne Research LiDAR (EAARL). These comparisons, based upon data collected from the Trinity and Klamath Rivers, California, and the Colorado River, Colorado, demonstrated that environmental conditions and postprocessing algorithms can influence the accuracy and utility of these surveys and must be given consideration. These factors can lead to mapping errors that can have a direct bearing on derivative analyses such as hydraulic modeling and habitat assessment. We discuss the water and substrate characteristics of the sites, compare the conventional and remotely sensed river‐bed topographies, and investigate the laser waveforms reflected from submerged targets to provide an evaluation as to the suitability and accuracy of the EAARL system and associated processing algorithms for riverine mapping applications.  相似文献   

18.
Federal and many state agencies are required to perform environmental justice analyses of their policies prior to implementing them to prevent undue impacts on low income and minority populations. However, little academic attention has been paid to the quality of these ex-ante environmental justice analyses. This investigation evaluates the methods used to perform environmental justice analyses during siting and permitting processes. The study uses both the California Energy Commission guidelines for environmental justice analyses and a method that geographically maps air pollution to perform ex-ante environmental justice analyses of three power plants. The objective is to see if results from using these two analysis methods differ substantially. Findings indicate that the mapping technique employed represents a substantial improvement over defining the impacted population using proximity methods because it accounts for the geographical distribution of the hazard. Furthermore, using multiple comparison benchmarks to determine whether the impacted population constitutes an environmental justice population improves upon existing methods by accounting for the spatial distribution of minority and low income populations and for the possibility that there is a relatively high or relatively low percentage of low income and minority persons in both the impacted and comparison regions.  相似文献   

19.
An inventory of volatile organic compound (VOC) and nitrogen oxides (NOx) emissions is an important tool for the management of ground-level ozone pollution. This paper has two broad aims: it illustrates the potential of a geographic information system (GIS) for enhancing an existing spatially-aggregated, anthropogenic emissions inventory (EI) for Tucson, AZ, and it discusses the ozone-specific management implications of the resulting spatially-disaggregated EI. The main GIS-related methods include calculating emissions for specific features, spatially disaggregating region-wide emissions totals for area sources, and adding emissions from various point sources. In addition, temporal allocation factors enable the addition of a multi-temporal component to the inventory. The resulting inventory reveals that on-road motor vehicles account for approximately 50% of VOC and NOx emissions annually. On-road motor vehicles and residential wood combustion are the largest VOC sources in the summer and winter months, respectively. On-road motor vehicles are always the largest NOx sources. The most noticeable weekday vs. weekend VOC emissions differences are triggered by increased residential wood combustion and increased lawn and garden equipment use on weekends. Concerning the EI's uncertainties and errors, on-road mobile, construction equipment, and lawn and garden equipment are identified as sources in the most need of further investigation. Overall, the EIs spatial component increases its utility as a management tool, which might involve visualization-driven analyses and air quality modeling.  相似文献   

20.
Movement of nutrients from livestock manure handling sites has the potential to negatively impact the environment. This study was conducted using electromagnetic induction (EMI) measurements to develop apparent soil electrical conductivity (EC(a)) maps to identify regions of nutrient buildup beneath an abandoned compost site. A trailer-mounted EM-38 coupled with a global positioning satellite system was towed across an area used for composting of feedlot manure. The resulting EC(a) maps were compared with known locations of compost rows confirming the alignment of row locations with high EC(a) regions. The identified rows were cored and compared with the region between the rows. The identified rows with a compost history demonstrated significant (P < 0.05) increases in soluble salts (1.6 times greater), NO3 (6.0 times greater), and Cl (2.0 times greater) compared with the area between the rows at a 1.5-m depth. Image processing techniques were used to display yearly changes that were associated with nutrient movement and transformations in the soil beneath the site. Correlations between EMI measurements and soil core analyses for NO3-N, Cl, and EC provided ancillary support for the EMI methods. The use of EMI for mapping of sites having a history of livestock waste application was effective in delineating high nutrient buildup areas and for observing spatial EC(a) changes over time.  相似文献   

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