Factors affecting spatial and temporal variability in nutrient and pesticide concentrations in the surficial aquifer on the Delmarva Peninsula PDF Download
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Author:
Publisher: DIANE Publishing
ISBN: 9781422325681
Category :
Languages : en
Pages : 112
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Book Description
Author:
Publisher: DIANE Publishing
ISBN: 9781422325681
Category :
Languages : en
Pages : 112
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Book Description
Author: Linda M. Debrewer
Publisher:
ISBN:
Category : Ground water
Languages : en
Pages : 44
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Author:
Publisher: Academic Press
ISBN: 0128023449
Category : Technology & Engineering
Languages : en
Pages : 223
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Book Description
Advances in Agronomy continues to be recognized as a leading reference and a first-rate source for the latest research in agronomy. Each volume contains an eclectic group of reviews by leading scientists throughout the world. As always, the subjects covered are varied and exemplary of the myriad of subject matter dealt with by this long-running serial. Timely and state-of-the-art reviews Distinguished, well recognized authors A venerable and iconic review series Timely publication of submitted reviews
Author: Paul D. Capel
Publisher: Geological Survey
ISBN: 9781411341821
Category : Agricultural chemicals
Languages : en
Pages : 216
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Format not distributed to depository libraries.
Author: Harsimrat Kaur
Publisher: Springer
ISBN: 3319952978
Category : Science
Languages : en
Pages : 139
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Book Description
This book explains the tragic tale of the Satluj floodplain since its inception. As a landscape this floodplain entity evolves and sets a niche to distinctive natural and cultural aspects. The historical reconstruction of the landscape transformation depicts the excessive human encroachment and development activities which leads to more than fifty percent of landscape transformation. Data set layers were generated in a geospatial environment, with the use of multiscale and multitemporal satellite imageries, empirical field verification, and ancillary data input. An integrated landscape model was hence formed in order to identify the causal links between natural and cultural aspects. The author shows a landscape transformation matrix and change detection maps to explain the spatial trends and patterns of land use and land cover change. Pixel wise land use and land cover gain-loss algorithm were identified and measured for a selected time period. Changing spatial pattern of land cover to land use ratio are explained with underlying local to regional level causes. The author thoroughly explains the satellite image interpretation and related methodology. This book provides the detailed transition journey of landscape conversion from resource rich natural entity to a human dominated ‘hazardscape’. It also explains how the expansion of population and related activities in the close vicinity of an active floodplain accentuates the problem of flood risks and how it affects the human and livestock life and creates economic loss. The author maps and explains the vector and magnitude of increased human pressure on the landscape and its adverse ecological implications, and describes issues with reference to the hazard status of the Punjab Satluj floodplain, including increased flood risk, increased pressure on agricultural land and depletion of resources, loss of biodiversity, qualitative and quantitative loss to surface and sub-surface water, and soil degradation (soil erosion, waterlogging and soil loss). Recommendations are provided with a detailed provision of potential applications with the underlying agenda of further conversion of this ecologically highly vulnerable flood prone ‘hazardscape’ to a Green Habitat. This book consist of two major themes: land use/land cover change and floodplain. The author answers all the geographical questions (what, where, when, why and how) related with both themes and provides an outlook to potential future prospects. The book is targeted at stakeholders, students, researchers and policy makers to optimize their interest and to guide them towards a positive charge in sustainable resource management through suitable and best possible sustainable utilization of landscape.
Author: Jacqueline Marie Brook
Publisher:
ISBN:
Category :
Languages : en
Pages : 315
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Book Description
This thesis presents two interrelated studies that consider nutrient management and seasonal changes in recharge on agricultural lands within the context of source water protection. The research focuses first on the management of the risk to groundwater quality through the implementation of various nutrient management practices and secondly considers the dynamic nature of the transport pathway to the groundwater system associated with seasonal changes in climate and hydrology. The combined results provide insight into several of the key factors influencing the protection of groundwater sources within the agricultural landscape. Field work was completed between 2009 and 2010 on an agricultural field near the City of Woodstock, Ontario. The site is located within a source water protection area; the two-year travel time zone of the Thornton Well Field which represents the primary water supply for the City of Woodstock and which has experienced chronic increases in nitrate concentrations over the last few decades. The wells are completed in glacial overburden consisting of intermingling sand and gravel till aquifers which overly a limestone bedrock aquifer. Agricultural best or beneficial management practices (BMPs) field have been implemented and monitored since 2004. The BMPs were adopted in order to reduce nitrogen losses to the aquifer, and consisted of a reduction in nitrogen fertilizer application rates over a series of agricultural fields located near the well The first study is a one year experiment designed to compare alternative nutrient management practices for corn. Combinations of fertilizer treatments with or without a legume cover crop (red clover) were assessed. The fertilizer treatments studied were: a polymer coated urea (slow-release fertilizer) applied at planting, a conventional urea applied at planting, side-dress treatment of a solution of urea and ammonium nitrate in water containing 28% nitrogen with two different application rates applied in the early summer, and a control. The legume cover crop was incorporated in the soil in the previous fall, and acts as a slow release fertilizer as nitrogen is made available to the following crop as the plants decompose. Treatments were compared based on crop yield, overall economic return, and the potential for nitrate leaching. The potential for nitrate leaching was evaluated with bi-weekly shallow soil core during the growing season, and deep soil cores taken before planting, after harvest and the following spring. The deep cores allowed changes in nitrate storage below the rooting zone to be assessed. The results of this study highlight the importance of timing of fertilizer applications and rate of fertilizer applications. Treatments which provide a delay in the release or application of fertilizer, the polymer-coated urea, the calculator-rate side-dress and the clover cover crop, were found to be advantageous. The polymer-coated urea treatments and side-dress treatments were found to reduce leaching compared to the conventional urea treatment. Treatments with the clover cover crops were not found to reduce crop yields or increase leaching potential, and lower fertilizer costs associated to this practice were found to have a positive economic effect. Plots treated with the high-rate side-dress fertilizer application lost more nitrate to the subsurface compared to the other treatment options, and an economic disadvantage was observed as yields did not compensate for higher fertilizer costs. The study highlights the advantages of the different treatments under study, which may be used to inform policy makers and farmers in the selection of economically and environmentally sustainable nutrient management BMP options. Groundwater monitoring at the site over the years has indentified interesting recharge dynamics, particularly in the vicinity of an ephemeral stream which develops annually during spring and winter melt events in a low lying area of the study site. It was hypothesized that rapid recharge could occur beneath the stream allowing for surface water to quickly reach groundwater, posing a threat to municipal water wells. The current framework of source water protection does not take into account the potential risk posed by this type recharge event. At this field site, rapid infiltration associated with this type of event may pose a risk to drinking water quality due to the proximity of the stream to the pumping wells and the nature of the aquifer. The second study examines rapid groundwater recharge processes beneath the ephemeral stream during the course of a spring melt in 2010. The goals of the study were to quantify recharge at one location beneath the stream and to assess whether temperature variations above the water table can be used as a tracer to reasonably estimate recharge during a short live recharge event. A novel housing for the temperature sensors was designed in order to deploy and position them into gravelly materials within the vadose zone, which reduced the potential for the formation of preferential pathways and permitted the retrieval of the sensors at a later date. Field data were collected during the course of the spring melt period from a network of groundwater monitoring wells and subsurface temperature sensors. Spatial and temporal changes in groundwater geochemistry, hydraulic head and temperature were were used to characterize recharge dynamics at the field site. Recharge beneath a segment of the ephemeral stream was quantified through the numerical analysis of the field data using Hydrus 1-D, a one-dimensional numerical model designed to simulate soil water flow and heat transport in variably saturated porous media. Site specific data were used to create the model domain, provide estimates of physical parameters, and to define initial and time variable boundary conditions. Model parameters were first calibrated by simulating periods where it was expected that soils would be gravity drained with minimal soil water flow, and then further refined by simulating the period when the ephemeral stream was present. A final set of parameters was determined, and the initial gravity drained conditions were re-simulated. The model was able to reproduce field observations under different flow scenarios using the final set of parameters, suggesting that the conceptual model and final model domain representative of the actual field conditions. The successful simulation of the field data sets under the different flow scenarios also increases confidence in the uniqueness of the model results. The model estimated that 0.15 m of recharge occurred beneath the instrumented site during the period between March 9th and March 22nd of 2010 when the ephemeral stream was present. This represents approximately a third of the expected total annual recharge for this location. Regional changes in hydraulic head, groundwater temperature and groundwater chemistry provided additional insight into the dynamic nature of the recharge process during the spring meld period and further illustrated the spatial variability of the aquifers' response to the stream. The study found that the use of temperature as a tracer provided useful and quantifiable insight into recharge phenomena. The results of this study suggest that high rates of rapid recharge occur beneath the ephemeral stream, and are spatially variable. This type of focused infiltration that occurs during the spring melt may represent a risk to municipal water quality if the infiltrating waters are carrying contaminants.
Author: Jeffrey Glenn Mutti
Publisher:
ISBN:
Category : Groundwater
Languages : en
Pages : 346
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Book Description
Groundwater nitrate contamination is a well-documented issue in the Southern Willamette Valley (SWV) of Oregon, as a Groundwater Management Area (GWMA) has recently been declared. As a GWMA, groundwater nitrate monitoring must occur until regional concentrations are below 7 mg/L NO3-N. However, the presence of temporal variability can make it difficult to determine if contamination exceeds a threshold and if contamination is increasing or decreasing over time. To examine the potential impact of temporal variability on groundwater nitrate monitoring in the SWV, a well network was created and sampled monthly for 15 months. Results indicate that substantial intra-well temporal variability is present, and that spatial variability of groundwater nitrate is greater than temporal variability. Generally, temporal variability was associated with recharge events, which flushed higher concentration soil-water into the aquifer. Though individual wells showed seasonality, network-wide seasonal trends were not statistically significant (which is believed to be caused by a dampening effect due to local heterogeneities). From a monitoring perspective, this implies that less frequent groundwater nitrate sampling (such as quarterly) can capture network-wide seasonal response to the same degree as monthly sampling. To determine how long-term land management practices are likely to impact regional nitrate leaching and future monitoring trends, a nitrogen loading model was created for the SWV. Present-day data were used to calibrate and validate the Soil and Water Assessment Tool (SWAT) model, with 3 alternative future scenarios then being evaluated. The effects of agrarian Groundwater Best Management Practices (GW-BMPs) were examined with respect to nitrate leaching in present and future scenarios. Modeled values indicate that agrarian GW-BMP implementation is a more effective agent for reduced nitrate leaching than land use change alone. Together, land use change and the adoption of GW-BMPs were found to decrease nitrate leaching values by 32 to 46% of their present-day rates. These predicted results do not include the impact of denitrification or changes in septic leaching, and therefore should be regarded with caution as they do not completely represent future conditions. Considering this, a conservative conclusion which can be drawn is that GW-BMP implementation is a safer alternative than reliance on projected land use/crop change alone for lessening groundwater nitrate concentrations in the GWMA. This is the first study to successfully apply SWAT as a tool to examine the spatial and temporal variability of nitrate leaching.
Author: Sharon E. Kroening
Publisher:
ISBN:
Category : Earth sciences
Languages : en
Pages : 122
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Author: National Research Council
Publisher: National Academies Press
ISBN: 0309082951
Category : Science
Languages : en
Pages : 449
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Book Description
The Clean Water Act (CWA) requires that wetlands be protected from degradation because of their important ecological functions including maintenance of high water quality and provision of fish and wildlife habitat. However, this protection generally does not encompass riparian areasâ€"the lands bordering rivers and lakesâ€"even though they often provide the same functions as wetlands. Growing recognition of the similarities in wetland and riparian area functioning and the differences in their legal protection led the NRC in 1999 to undertake a study of riparian areas, which has culminated in Riparian Areas: Functioning and Strategies for Management. The report is intended to heighten awareness of riparian areas commensurate with their ecological and societal values. The primary conclusion is that, because riparian areas perform a disproportionate number of biological and physical functions on a unit area basis, restoration of riparian functions along America's waterbodies should be a national goal.
Author:
Publisher:
ISBN:
Category : Arsenic
Languages : en
Pages : 124
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Book Description
V.3 ... consists of individual chapters that describe 1) the conceptual background for radionuclides, including tritium, radon, strontium, technetium, uranium, iodine, radium, thorium, cesium, plutonium-americium and 2) data requirements to be met during site characterization.
