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1
Roth, Bob, Bryant Gardner e Barry Tickes. "Barley Response to Water and Nitrogen Levels". College of Agriculture, University of Arizona (Tucson, AZ), 1987. http://hdl.handle.net/10150/203803.
Testo completoAbstract (sommario):
Results from one year's data show that yields of more than five tons per acre are feasible for Fiesta, Gustoe and NKX -1558 barley cultivars. The cultivar Barcott is a shorter season variety; yields were reduced by approximately one ton per acre, compared to the other cultivars. Additional data needs to be collected to verify the amounts of water and nitrogen required for obtaining optimum production.
2
Husman, S. H., M. J. Ottman, K. L. Johnson e R. J. Wegener. "Durum Response to Soil Water Depletion Levels". College of Agriculture, University of Arizona (Tucson, AZ), 1999. http://hdl.handle.net/10150/205173.
Testo completoAbstract (sommario):
Research has not been conducted in Arizona to determine when to irrigate wheat based on soil water depletion levels. The purpose of this work is to establish the optimum irrigation timing based on depletion of plant available water in the soil. A field experiment was conducted at the Maricopa Agricultural Center testing irrigation of wheat at 35, 50, 65, and 80% depletion of plant available water in the soil for two durum varieties, Kronos and Westbred 881. Grain yields averaged over the two varieties were 6479, 5099, 4283, and 4145 lbs/acre for the 35, 50, 65, and 80% depletion levels, respectively. The results of this study indicate that more frequent irrigations may be required than is typically practiced to optimize wheat grain yields in Arizona. This work will be repeated during the 1999-2000 growing season and the results from both years will be evaluated before general conclusions are drawn.
3
Husman, Stephen H., Michael J. Ottman, R. J. Wegener e M. T. Rogers. "Barley Response to Soil Water Depletion Levels, 2000". College of Agriculture, University of Arizona (Tucson, AZ), 2000. http://hdl.handle.net/10150/204060.
Testo completoAbstract (sommario):
This research represents the first year of a project to determine when to irrigate barley based on soil water depletion levels. The purpose of this work is to establish the optimum irrigation timing based on depletion of plant available water in the soil. A field experiment was conducted at the Maricopa Agricultural Center testing irrigation of barley at 35, 50, 65, and 80% depletion of plant available water in the soil for two barley varieties, Baretta and Max. Grain yields averaged over the two varieties were 8415, 7735, 7512, and 4553 lbs/acre for the 35, 50, 65, and 80% depletion levels, respectively. The results of this study indicate irrigating at 35% soil water depletion is optimal for barley grain yield.
4
Husman, Stephen H., Michael J. Ottman, R. J. Wegener e M. T. Rogers. "Durum Response to Soil Water Depletion Levels, 2000". College of Agriculture, University of Arizona (Tucson, AZ), 2000. http://hdl.handle.net/10150/204098.
Testo completoAbstract (sommario):
This research represents the second year of a project to determine when to irrigate wheat based on soil water depletion levels. The purpose of this work is to establish the optimum irrigation timing based on depletion of plant available water in the soil. A field experiment was conducted at the Maricopa Agricultural Center testing irrigation of wheat at 35, 50, 65, and 80% depletion of plant available water in the soil for two durum varieties, Kronos and Westbred 881. Grain yields averaged over the two varieties were 6787, 6494, 5460, and 3067 lbs/acre for the 35, 50, 65, and 80% depletion levels, respectively. The results of this study indicate irrigating at 50% soil water depletion or less is optimal for wheat grain yield.
5
Cooling, Marcus. "Adaptations of aquatic macrophytes to seasonally fluctuating water levels /". Title page, contents and summary only, 1996. http://web4.library.adelaide.edu.au/theses/09PH/09phc7745.pdf.
Testo completo
6
Sazova, Yeliz Özgen Tamerkan. "Investigation of Dicofol And Endosulfan Pesticide Levels In Tahtali Dam Water Or Drinking Water/". [s.l.]: [s.n.], 2004. http://library.iyte.edu.tr/tezler/master/kimya/T000500.pdf.
Testo completo
7
Johnson, Sissy Daniel. "Concentrations [sic] levels of fluoride in bottled drinking water and filtered water using home filtration systems". Morgantown, W. Va. : [West Virginia University Libraries], 2000. http://etd.wvu.edu/templates/showETD.cfm?recnum=1439.
Testo completoAbstract (sommario):
Thesis (M.S.)--West Virginia University, 2000.Title from document title page. Document formatted into pages; contains vi, 47 p. : ill. (some col.) Vita. Includes abstract. Includes bibliographical references (p. 44-46).
8
Ottman, Michael J., e Stephen H. Husman. "Barley response to soil water depletion levels at Maricopa, 2002". College of Agriculture, University of Arizona (Tucson, AZ), 2002. http://hdl.handle.net/10150/203859.
Testo completoAbstract (sommario):
This research represents the second year of a project to determine when to irrigate barley based on soil water depletion levels. The purpose of this work is to establish the optimum irrigation timing based on depletion of plant available water in the soil. A field experiment was conducted at the Maricopa Agricultural Center testing irrigation of barley at 35, 50, 65, and 80% depletion of plant available water in the soil for two barley varieties, Baretta and Max. Grain yields for the 35, 50, 65, and 80% depletion levels were 8319, 7296, 5606, and 3404 lbs/acre for Baretta and 9164, 8403, 6463, and 3416 lbs/acre for Max, respectively. The yield increase averaged across varieties from irrigating at 35% rather than 50% depletion is 893 lbs/acre, which has a value of $45.54/acre assuming a grain price of $5.10/cwt. However, the cost of producing this grain is $54.33/acre due the cost of two additional irrigations ($44/acre), 30 lbs additional nitrogen per acre ($8.10/acre), and increased hauling cost ($2.23/acre). The profitability of irrigating at 35% rather than 50% depletion is improved with an increase in grain price or decrease in water cost.
9
Ottman, Michael J., e Stephen H. Husman. "Durum response to soil water depletion levels at Stanfield, 2002". College of Agriculture, University of Arizona (Tucson, AZ), 2002. http://hdl.handle.net/10150/203860.
Testo completoAbstract (sommario):
This research was conducted to test the effect of soil water depletion levels on durum productivity. An experiment was conducted at a commercial farm in Stanfield where irrigations were applied at 35, 50, or 65% depletion of plant available soil water. These soil water depletion levels were estimated from soil texture and weather data. The grain yields obtained with 35, 50, and 65% depletion were 6718, 6324, and 4752 lbs/acre, respectively. Grain protein decreased and HVAC increased by irrigating more frequently at lower depletion levels. Irrigating at 50% depletion was the most economical in this study considering irrigation costs and grain quality discounts.
10
Wilkerson, Carissa N. "Analysis of Extreme Water Levels in the Lower Chesapeake Bay". W&M ScholarWorks, 2013. https://scholarworks.wm.edu/etd/1539617934.
Testo completoAbstract (sommario):
In order to better understand storm tides in the Lower Chesapeake Bay, water levels during eleven storms at eight stations were analyzed using several methods. Storm tide was separated into individual components: predicted tide, storm surge, and local anomaly. These components were quantified and then analyzed for spatial trends. Trends were verified using Principal Component Analysis (PCA). The predicted tide and the storm surge each exhibited spatial variability, while the anomaly was spatially uniform. Anomaly values varied from storm to storm, ranging from 0.01m to 0.3m.
Potential water levels were determined for each storm by applying a time-shift to match the minimum or maximum predicted tide with the maximum storm surge and the anomaly. In many cases if the maximum observed level had occurred at high tide, the potential observed could have been as much as 0.5m larger than actually experienced. If the maximum observed level had occurred at low tide, the potential observed level could have been as much as 0.8m lower. Thirteen-year potential maximum results indicate that this potential maximum has not been reached at any station. Stations are between 0.3m and 0.5m away from their thirteen-year potential maximum.
Maximum storm tide values were assessed relative to both mean lower low water (MLLW) and highest astronomical tide (HAT). HAT was determined to be a better metric for storm impact than MLLW. Integrated intensity, or area under the storm tide curve relative to HAT, is a metric that combines storm duration with the height above HAT. Integrated intensity values were generally higher during extratropical storms than during tropical storms due to the long duration of these storms.
11
Whitener, Benjamin Towson. "Effect of Water Levels and Beach Availability on Waterfront Homes". Oberlin College Honors Theses / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=oberlin1431178092.
Testo completo
12
Cobba, Hussain M. A. Raji. "Pricing, investment, and demand management in the water supply industry". Thesis, University of Leicester, 1988. http://hdl.handle.net/2381/35472.
Testo completoAbstract (sommario):
The subject matter of this thesis is the definition, measurement and use of marginal cost as a tool of analysis to assist the process of decision-making in the water supply industry. Demand management is viewed in broad terms to include the establishment of an optimal structure and level of prices and investment in optimal capacity as well as investment in demand-restraining measures such as leakage detection and control. The study examines the definition of marginal cost as a benchmark for price setting. It provides empirical estimates of the various components of marginal cost of water supply in the Hampshire area, part of the Southern Water Authority. These estimates assume an exogenously determined level of demand and therefore exclude any possible direct interaction between the pricing and investment decisions. Departing from this tradition the study also examines a number of models where, under specific assumptions, optimal prices, output and capacity levels over a chosen planning horizon are simultaneously determined. This allows for direct interaction between the pricing and investment decisions. The study simulates optimal paths of prices, output and capacity expansion in the Hampshire area. This is carried out under various assumptions, one of which admits the potential of staging capacity expansion in order to take advantage of economies of scale in the capital cost function. An analysis of leakage detection and control as a demand management tool is presented in the final part of the study. The purpose of this analysis is to investigate how leakage detection and control may be conducted using either cost-benefit analysis or an appropriately defined tool of marginal cost.
13
Persio, Andrew Franklin. "Assessment of changes in the water-surface profile of the lower canyon of the Little Colorado River, Arizona". Thesis, The University of Arizona, 2004. http://etd.library.arizona.edu/etd/GetFileServlet?file=file:///data1/pdf/etd/azu_etd_hy0124_sip1_w.pdf&type=application/pdf.
Testo completo
14
Fraher, Patrick M. A. "Environmental sensor validation". Thesis, University of Oxford, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.308651.
Testo completo
15
Burston, Joanna. "Stochastic model of extreme coastal water levels, New South Wales, Australia". Connect to full text, 2008. http://ses.library.usyd.edu.au/handle/2123/4033.
Testo completoAbstract (sommario):
Thesis (Ph. D.)--University of Sydney, 2008.Title from title screen (viewed February 12, 2009). Includes graphs and tables. Submitted in fulfilment of the requirements for the degree of Doctor of Philosophy to the School of Geosciences, Faculty of Science. Includes bibliographical references. Also available in print form.
16
Prats, Kyra Alexandra. "Rivermouth Ecosystem Hydrogeomorphology: Relationships Among Wetland Area, Water Levels, and Streamflow". Thesis, Boston College, 2013. http://hdl.handle.net/2345/3085.
Testo completoAbstract (sommario):
Thesis advisor: Martha Carlson MazurRivermouths are dynamic systems characterized by hydrologic mixing, where water, energy, sediment and nutrients from both river and receiving water unite to form a unique yet variable environment. Water levels in these environments are thus defined by, and subject to, streamflow from the river and lake-level fluctuations. Long-term fluctuations in water levels affect hydrogeomorphic structure, as well as wetland structure, distribution, and composition. A better understanding of these dynamics will help us to comprehend the processes that govern changes in wetland area and, thus, the breadth of the ecosystem services that estuarine wetlands provide. To this end, this study examined how wetland plant communities have changed through time in relation to long-term changes in water levels from both river and lake systems, using historic aerial photograph interpretation in three rivermouths on Lake Michigan. Additionally, the observed patterns of historic water levels and streamflows were used to inform our predictions for the future in light of climate changes. Results showed that higher water levels and peak streamflows led to less wetland area; average streamflow did not play a statistically detectable role in rivermouths that had lake-dominated morphologies but was significant in the rivermouth system that was riverine dominated. This suggests that varying rivermouth morphologies respond differently to lake and stream dynamics. Restoration decisions that take rivermouth morphology into account will be important as these systems continue to change both naturally and due to climate or other anthropogenic disturbances. It is important to realize not only the extent to which humans are affecting rivermouth systems, but also the interplay between water levels, streamflows, hydrogeomorphology, and wetland ecology within these systems themselves, so as to better understand the necessary steps for restoration
Thesis (BS) — Boston College, 2013
Submitted to: Boston College. College of Arts and Sciences
Discipline: Geology & Geophysics Honors Program
Discipline: Earth and Environmental Science
17
Williams, Chavon R. "A National survey of Mercury levels in South Africa's water management areas". Thesis, University of the Western Cape, 2010. http://etd.uwc.ac.za/index.php?module=etd&action=viewtitle&id=gen8Srv25Nme4_8674_1298356510.
Testo completoAbstract (sommario):
This study forms part of a broader project co-funded by the Water Research Commission (WRC), and CSIR Parliamentary Grant (PG) and Strategic Research Panel (SRP) research grants, aimed at surveying selected water resources within the 19 Water Management Areas in South Africa. Furthermore, it aims at determining the concentrations of Hg and MeHg in various environmental compartments collected from priority water resources, to identify the potential Hg hotspots, and to assess the degree of compliance with national and international guidelines. Mercury concentrations in the environment have increased globally and this has caused much anxiety in terms of the adverse effects it has on aquatic ecosystems, their organisms, and the communities they sustain. Human health risks associated with the consumption of fish elevated containing Hg concentrations have received minimal attention particularly in South Africa. It is imperative that any potential adverse impacts of Hg on aquatic ecosystems, and the subsequent impacts on human health, be investigated.
18
Metzler, F., S. Husman e R. Wegener. "Lint Yield Response to Varied Levels of Water Stress and Consumptive Water Use Requirements of Upland Cotton". College of Agriculture, University of Arizona (Tucson, AZ), 1997. http://hdl.handle.net/10150/210946.
Testo completoAbstract (sommario):
Lint yield response to varied Management Allowed Depletion Levels (MADL), and consumptive water use rates were determined for four upland cotton varieties (D&PL 5415, D&PL NuCotn 33B, D&PL 5816, and STV 474) at the Maricopa Agricultural Center. Four irrigation treatments based on MADL of 35% (Very Wet), 50% (Wet), 75% (Medium) and 90% (Dry) of available moisture were used to schedule irrigations after May 16. The Very Wet and Wet treatments showed statistically similar yields which were much greater than the Medium and Dry treatments. Irrigation return intervals of six to ten days from early June thru late July appeared to provide the greatest lint yields. Consumptive water use appears to reach its maximum during the peak bloom period of the fruiting cycle. Following peak bloom, water use gradually diminishes.
19
Oliver, Marcel 1963. "Mathematical investigation of models of shallow water with a varying bottom". Diss., The University of Arizona, 1996. http://hdl.handle.net/10150/191198.
Testo completoAbstract (sommario):
This dissertation is a mathematical investigation of the so-called lake and the great lake equations, which are shallow water equations that describe the long-time motion of an inviscid, incompressible fluid contained in a shallow basin with a slowly spatially varying bottom, a free upper surface and vertical side walls, under the influence of gravity and in the limit of small characteristic velocities and very small surface amplitude. It is shown that these equations are globally well-posed, i.e. that they possess unique global weak solutions that depend continuously on the initial data and on the bottom topography. Provided the initial data is in a class of sufficiently differentiable functions, it remains a member of that class for all times. In other words, the lake and great lake equations have global classical solutions. Moreover, if the equations are posed on a space-periodic domain and the initial data is real analytic, the solution remains real analytic for all times. The proof is based on a characterization of Gevrey classes in terms of decay of Fourier coefficients. Finally, a partial mathematical justification of the formal derivation of the lake equations is given. It is shown that solutions of the lake equation stay close to solutions of the rigid lid equations—the three dimensional Euler equations in the limit of small surface wave amplitude—in the following sense: For every error bound 6 there exists a time T = T(ε) such that for all times t ∈ [0, T] the difference between a solution to the lake equations and the solution to the rigid lid equation corresponding to the same initial data is less than E in a suitably chosen norm. Moreover, T tends to infinity as the aspect ratio of the basin tends to zero.
20
Ali, Syed Mahtab. "Climate change and water management impacts on land and water resources". Curtin University of Technology, Faculty of Engineering and Computing, Dept. of Civil Engineering, 2007. http://espace.library.curtin.edu.au:80/R/?func=dbin-jump-full&object_id=18688.
Testo completoAbstract (sommario):
This study evaluated the impacts of shallow and deep open drains on groundwater levels and drain performance under varying climate scenarios and irrigation application rates. The MIKE SHE model used for this study is an advanced and fully spatially distributed hydrological model. Three drain depths, climates and irrigation application rates were considered. The drains depths included 0, 1 and 2 m deep drains. The annual rainfall and meteorological data were collected from study area from 1976 to 2004 and analysed to identify the typical wet, average and dry years within the record. Similarly three irrigation application rates included 0, 10 and 16 ML/ha-annum. All together twenty seven scenarios (3 drains depths, 3 climates and 3 irrigation application rates) were simulated. The observed soil physical and hydrological data were used to calibrate and validate the model. Mean square error (R[superscript]2) of the simulated and observed water table data varied from 0.7 to 0.87. Once validated the MIKE SHE model was used to evaluate the effectiveness of 1 and 2 metre deep drains. The simulated water table depth, unsaturated zone deficit, exchange between unsaturated and saturated zones, drain outflow and overland flow were used to analyse their performance. The modeling results showed that the waterlogging was extensive and prolonged during winter months under the no drainage and no irrigation scenario. In the wet climate scenario, the duration of water logging was longer than in the average climate scenario during the winter months. In the dry climate scenario no waterlogging occurred during the high rainfall period. The water table reached soil surface during the winter season in the case of wet and average climate. For the dry climate, the water table was about 0.9 metres below soil surface during winter.One and 2 metre deep drains lowered the water table up to 0.9 and 1.8 metres in winter for the wet climate when there was no irrigation application. One metre deep drains proved effective in controlling water table during wet and average climate without application of irrigation water. One metre deep drains were more effective in controlling waterlogging a in wet, average and dry years when the irrigation application rate was 10 ML/ha-annum. With 16 ML/ha-annum irrigation application, 1 metre deep drains did not perform as efficiently as 2 metre deep drains in controlling the water table and waterlogging. In the dry climate scenario, without irrigation application, 1 metre deep drains were not required as there was not enough flux from rainfall and irrigation to raise the water table and create waterlogging risks. Two metre deep drains lowered the water table to greater depths in the wet, average and dry climate scenarios respectively when no irrigation was applied. They managed water table better in wet and average climate with 10 and 16 ML/ha-annum irrigation application rate. Again in the dry climate, without irrigation application 2 metre deep drains were not required as there was a minimal risk of waterlogging. The recharge to the groundwater table in the no drainage case was far greater than for the 1 and 2 metre deep drainage scenarios. The recharge was higher in case of 1 metre deep drains than 2 metre deep drains in wet and average climate during winter season.
There was no recharge to ground water with 1 and 2 metre deep drains under the dry climate scenarios and summer season without irrigation application as there was not enough water to move from the ground surface to the unsaturated and saturated zones. When 10 ML/ha-annum irrigation rate was applied during wet, average and dry climate respectively, 1 metre deep drains proved enough drainage to manage the recharge into the groundwater table with a dry climate. For the wet and average climate scenarios, given a 10 ML/ha-annum irrigation application rate, 2 metre deep drains managed recharge better than 1 metre deep drains. Two metres deep drains with a 10 ML/ha-annum irrigation application rate led to excessive drainage of water from the saturated zone in the dry climate scenario. Two metres deep drains managed recharge better with a 16 ML/ha-annum irrigation application rate in the wet and average climate scenarios than the 1 metre deep drains. Two metres deep drains again led to excessive drainage of water from the saturated zone in dry climate. In brief, 1 metre deep drains performed efficiently in the wet and average climate scenarios with and without a 10 ML/ha-annum irrigation application rate. One metre deep drains are not required for the dry climate scenario. Two metre deep drains performed efficiently in the wet and average climate scenarios with 16 ML/ha-annum irrigation application rate. Two metre deep drains are not required for the dry climate scenario.
21
Erdoğan, Murat Özgen Tamerkan. "Investigation of dichlorvos (DDVP) and trifluralin pesticide levels in Tahtalı dam water/". [s.l.]: [s.n.], 2002. http://library.iyte.edu.tr/tezler/master/kimya/T000161.pdf.
Testo completo
22
Park, Gee Hoon. "Determining phosphate levels in natural water using a novel electrochemical measurement device". Thesis, Massachusetts Institute of Technology, 2020. https://hdl.handle.net/1721.1/127729.
Testo completoAbstract (sommario):
Thesis: Ph. D., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2020Cataloged from PDF of thesis.
Includes bibliographical references (pages 157-177).
Current measurement of the phosphorus level in natural water are based on the phosphomolybdenum blue (PMB) method. In this method, the phosphate and molybdate ion form 12-molybdophosphoric acid (12-MPA) which is reduced to yield intensely coloured PMB, and its intensity is correlated with the phosphate concentration using spectrophotometry. Despite its well-established sensitivity and selectivity to the phosphate ion, commercially available in situ portable measurement devices suffer from their large footprints and limited working time. This is mainly because the wet chemistry of the PMB method requires a constant supply of liquid reagents of which volume determines the footprint and working time of the device. Such limitations of the existing methods make it difficult to access the temporal and spatial information of the phosphorus level in natural water which is crucial in the control of eutrophication.
In this thesis, we designed, fabricated, and evaluated two novel electrochemical phosphate detection devices that offer unique opportunities to be developed into portable, in-situ, and automated phosphate detection devices. The detection of phosphate is based on the formation of 12-MPA, wherein reagents are supplied in situ by the anodic dissolution of molybdenum (Mo). The first version of the device with two Mo electrodes in two separate chambers demonstrated that reducing the sample volume of the device reduces the time of detection and the energy consumption per measurement based on the Mo oxidation, when compared to the current state of the art (2 min and 900 mJ versus 70 min and 18 J, respectively). The second version device is improved further by simplifying the system into a single chamber with a single Mo electrode, which additionally decreases the response time to 30 s and the energy consumption to 4 mJ.
The experimental results with these two devices demonstrate the capability of phosphate determination (0.1 to 25 pM) in a high conductivity background solution (0.1 M NaCl), such as seawater, without significant interference from silicate ions. In addition, the second version of the device broadens its application into other types of natural water with low conductivity, and provides a promissing possibility to be further developed into an open-cell type sensor.
by Gee Hoon Park.
Ph. D.
Ph.D. Massachusetts Institute of Technology, Department of Mechanical Engineering
23
Dickinson, Jesse Ervin, e Jesse Ervin Dickinson. "Inferring time-varying recharge from inverse analysis of long-term water levels". Thesis, The University of Arizona, 2003. http://hdl.handle.net/10150/626918.
Testo completoAbstract (sommario):
Water levels in alluvial aquifers of the Southwest typically vary in response to time
varying rates of mountain-front recharge. This suggests the possibility of inferring time
varying recharge rates on the basis of long-term water-level records. Presumably, these
recharge rates depend on variations in precipitation rates due to known climate cycles
such as the El Nino/Southern Oscillation index and the Pacific Decadal Oscillation. This
investigation examined the inverse application of a one-dimensional analytical model for
periodic flow [Townley, 1995] to estimate periodic recharge variations on the basis of
water-level variations in long-tenn water-level records. Time-varying water level records
at various locations along a flow path were obtained by simulation of ground-water flow
in numerical models of idealized basins. Time-varying recharge was represented as
sinusoidal recharge of a single period or as a composite of multiple periods of length
similar to known climate cycles. Periodic water level components, reconstructed using
singular spectrum analysis (SSA), were used to calibrate the analytical model to estimate
each recharge component. The results demonstrate that periodic, time-varying recharge
rates can be estimated from hydrologic time series such as long-term water level records.
The results also demonstrate that periodic recharge estimates were most accurate in
basins with nearly uniform transmissivity, and that the accuracy of the recharge estimates
depended on the monitoring well locations.
24
Rice, Susan C. "Spatio-temporal Variation of Nitrate Levels in Groundwater in Texas, 1970 to 2010". Thesis, University of North Texas, 2012. https://digital.library.unt.edu/ark:/67531/metadc177244/.
Testo completoAbstract (sommario):
This study looks at spatial variation of groundwater nitrate in Texas and its fluctuations at 10 year increments using data from the Texas Water Development Board. While groundwater nitrate increased in the Ogallala and Seymour aquifers across the time period, the overall rate in Texas appears to be declining as time progresses. However, the available data is limited. Findings show that a much more targeted, knowledge based strategy for sampling would not only reduce the cost of water quality analysis but also reduce the risk of error in these analyses by providing a more realistic picture of the spatial variation of problem contaminants, thereby giving decision-makers a clearer picture on how best to handle the reduction and elimination of problem contaminants.
25
Cheng, Kai-chien. "Analysis of water level measurements using GPS". Connect to resource, 2005. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1127151397.
Testo completoAbstract (sommario):
Thesis (Ph. D.)--Ohio State University, 2005.Title from first page of PDF file. Document formatted into pages; contains xvi, 180 p.; also includes graphics (some col.). Includes bibliographical references (p. 168-180). Available online via OhioLINK's ETD Center
26
Betton, Catherine. "Nitrate-N levels in British streams and rivers : a countrywide perspective". Thesis, University of Exeter, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.277094.
Testo completo
27
Mulas, Dani. "Levels and behaviour of radionuclides in water treatment plants : the case of the Barcelona metropolitan area urban water cycle". Doctoral thesis, Universitat Politècnica de Catalunya, 2020. http://hdl.handle.net/10803/668856.
Testo completoAbstract (sommario):
The Barcelona metropolitan area (BMA; 3.2 M inhabitants) has an integrated urban water cycle management. Different type of treatment plants are located along the drinking, sewerage and reuse networks where specific treatments are applied to guarantee a good enough standard of the water quality. The presence of radionuclides in treatment plants and in the aquatic environment is well known. Primordial and daughters, cosmogenic, global fall-out and nuclear-legacy radionuclides can be found in the urban water cycle. Moreover in nuclear medicine (NM), short-lived radionuclides are administered to patients, excreting part directly into the sewage network and entering into the urban water cycle. Thus, the levels of radionuclides in waters and materials from water treatment plants were experimentally checked in the BMA in order to understand the behaviour during the water treatment and to perform a risk assessment. An integrated study focused on the study of the radionuclides levels at different three types of water treatment plants from the same network was carried out. A total of 233 samples were taken at 1 drinking water treatment plant (DWTP), 7 wastewater treatment plants (WWTPs) and 1 reclaimed water treatment plant (RWTP). The concentrations were determined by gamma-spectroscopy techniques after acquisitions performed by high-purity germanium detectors. Primordial and daughters radionuclides were found in materials from the DWTP studied and the highest specific activities found for sludge, sand and reverse osmosis brine corresponded to K-40. Nevertheless, the maximum concentration in the case of granular activated carbon was found for U-238. Moreover cosmogenic Be-7 and fall-out Cs-137 were found in sludges. A total of 5 different NM radionuclides were found in the analysis carried out in the samples from the 7 WWTPs. In the case of water and sewage sludge the highest maximum values and detection frequencies corresponded to Tc-99m and I-131. Moreover Ga-67, In-111 and I-123 were found but showing significantly lower levels. The detection frequencies and the mean levels found at the WWTPs of Ga-67, Tc-99m, In-111 and I-131 agreed with the NM radionuclides total activity administered in the region studied. Furthermore the concentrations and detection frequencies were significantly higher in the sewage sludge samples taken at the very large-sized WWTP-1 (325,000 m3/d), partially explained by their low sludge age. Medically-derived I-131 was also found in reclaimed water for reuse from the RWTP and materials from DWTP, which represent novel contributions to the current knowledge in this field.
Taking into account the present findings some considerations from the radiological protection point of view can be done. Despite the presence of radionuclides in the DWTP materials, they do not pose a radiological risk. In the case of the WWTPs and the RWTP studied, the levels found in waters and materials do not represent a significant risk, however, I-131 concentrations were pointed out as the most significant. With the aim to achieve a better understanding of I-131 behaviour in WWTPs and predict the I-131 levels novel methods of I-131 partitioning analysis as well as prognosis models were adapted successfully to a WWTP. I-131 partitioning results pointed out that the settling fraction predominates in the reactor while in the rest of the WWTP samples dissolved iodide fraction was the most significant. Furthermore the activated sludge reactors from WWTPs were revealed as the key step for I-131 removal from wastewater. Specifically, reactors with the highest total nitrogen kjeldahl removal were also the most effective for I-131 reduction. Regarding the I-131 modelling a total of 82 % of simulated data fit with the experimental results in the sewage effluent within uncertainties.El Área Metropolitana de Barcelona (AMB; 3.2 M de habitantes) posee un sistema integrado para la gestión del ciclo urbano del agua con diferentes tipos de plantas de tratamiento. En las redes de agua potable, residual y regenerada se aplican tratamientos específicos para garantizar los estándares de calidad requeridos en cada caso. Estudios previos en plantas de tratamiento de aguas revelan la presencia de radionúclidos primordiales y de su cadena de desintegración, cosmogénicos y procedentes de accidentes y del legado nuclear. Además, en medicina nuclear (MN) radionúclidos artificiales de vida corta son administrados a pacientes, dichos isótopos son posteriormente excretados entrando en el ciclo urbano del agua a través del agua residual. En el presente estudio en el AMB las concentraciones de radionúclidos en aguas y materiales de las plantas de tratamiento se han estudiado de forma integrada con el objetivo de determinar su comportamiento durante el tratamiento y realizar una evaluación radiológica de los niveles. El estudio ha incluido 233 muestras tomadas en tres tipos diferentes de plantas de tratamiento, 7 estaciones depuradoras de agua residual (EDAR), 1 estación de regeneración de agua (ERA) y de 1 estación de tratamiento de agua potable (ETAP). Las concentraciones de radionúclidos se han determinado con detectores de germanio de alta pureza mediante la aplicación de técnicas de espectrometría gamma. Radionúclidos primordiales y de su cadena de desintegración fueron detectados en los materiales sólidos de la ETAP. Las actividades más altas en el caso de los fangos, las arenas y el rechazo del osmosis inversa correspondieron al K-40 mientras que en el caso de carbón activo granulado al U-238. Además, se confirmó la presencia de Be-7 y Cs-137. Un total de 5 radionúclidos relacionados con la MN fueron detectados en los análisis de las muestras de las 7 EDARs. Respecto a las aguas y los fangos analizados las máximas concentraciones y los más detectados fueron el Tc-99m y el I-131. Además, fueron detectados en concentraciones más bajas el Ga-67, In-111 y el I-123. Las frecuencias de detección y niveles concordaron con la actividad total administrada en la zona de estudio. Especial mención merecen los resultados de la EDAR-1 (325,000 m3/d), de grandes dimensiones, ya que los valores y frecuencia de detección fueron mayores que en el resto lo que se explica en parte por la reducida edad del fango que genera. El I-131 se encontró también en agua regenerada de la ERA y los materiales de EDAR estudiadas, lo que representa una nueva aportación por a lo que I-131 de origen médico se refiere. Con los presentes resultados se pueden realizar las siguientes consideraciones desde el punto de vista de la protección radiológica. A pesar de la presencia de radionúclidos en aguas y materiales de las plantas estudiadas, las concentraciones de actividad determinadas no suponen un riesgo radiológico significativo. Sin embargo, puede afirmarse que las concentraciones de I-131 fueron las más relevantes. Con el objetivo de avanzar en el conocimiento del comportamiento de I-131 en EDARs y predecir sus concentraciones nuevas metodologías de análisis del I-131 así como modelos predictivos se adaptaron satisfactoriamente a una de las EDAR estudiadas. La distribución fisicoquímica del I-131 resultó en que la fracción precipitable predominó en las muestras tomadas en el reactor ya que es un tratamiento clave para su eliminación, mientras que en el resto de muestras analizadas el yodo inorgánico disuelto fue mayoritario. Otro descubrimiento relevante fue constatar que los reactores que presentaban una mayor disminución de la concentración del nitrógeno kjeldahl mostraron también una reducción significativa del I-131. Respecto al modelo, un total del 82 % de las concentraciones de I-131 simuladas para los efluentes de planta se ajustaron satisfactoriamente a los resultados experimentales considerando las incertidumbres
28
Podziewski, Judy, Janice Coons e Kate Lormand. "Tolerance of Terpary and Navy Beans to Different Salt Levels in Irrigation Water". College of Agriculture, University of Arizona (Tucson, AZ), 1989. http://hdl.handle.net/10150/214256.
Testo completo
29
Hofmann, W. C., J. L. Stroehlein, B. B. Taylor, C. Michaud e P. T. Else. "Response of Surface Drip Irrigated Cotton to Water Levels, Varieties and Plant Populations". College of Agriculture, University of Arizona (Tucson, AZ), 1986. http://hdl.handle.net/10150/219748.
Testo completoAbstract (sommario):
The 1985 and 1986 Cotton Reports have the same publication and P-Series numbers.A drip irrigation trial was conducted at Eloy, Arizona to investigate optimal irrigation levels for cotton. Five irrigation levels (23.6, 26.7, 29.9, 32.8 and 33.8 acre inches) were applied to DPL 41, DPL 90 and DPL 774. The varieties were planted at 5, 10, and 20 pounds/acre. There were no statistical differences in yield in the 3 wetter irrigation treatments. Both of the drier water levels produced significantly lower yields. Significant differences were also detected in the response of the varieties and populations.
30
Schiffman, Sara. "Sodium (Na) Levels in Drinking Water (H20) and Development of Hypertension in Children". Honors in the Major Thesis, University of Central Florida, 2013. http://digital.library.ucf.edu/cdm/ref/collection/ETH/id/962.
Testo completoAbstract (sommario):
This integrative review of the literature focused on sodium (Na) content in drinking water (H?O) supplies and the subsequent effect on blood pressure levels in children. Studies for this review were drawn from the Cumulative Index of Nursing and Allied Health, PubMED, Science and Technology Databases, PsychInfo, United States (US) Environmental Protection Agency (EPA) and EPA in Florida websites. Criterion for inclusion in the data base searches were hypertension, high blood pressure, sodium in drinking water, drinking water salinity, children or preg'. Subsequently, further article selection criteria included children (under 18 years of age) and published in the English language (N=59). Findings of the review as summarized in this thesis could guide nursing research, education, policy and practice related to primary, secondary and tertiary interventions associated with sodium levels in drinking as a contributing factor to blood pressure levels in children.B.S.N.
Bachelors
Nursing
Nursing
31
Wegerich, Kai. "Institutional change in water management at the local and provincial levels in Uzbekistan". Thesis, SOAS, University of London, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.404826.
Testo completoAbstract (sommario):
The dis-integration of the Soviet Union has led to changes in agricultural and natural resource management in the Central Asian successor states. These changes affected not only the international and national levels of governance but also the provincial and local level governance of the different republics. The focus of the research is on institutional change at the local level in the agricultural sector in Uzbekistan. The study area is located in the downstream regions of the Amu Darya basin, in the Khorezm province and the Karakalpakstan republic. Since the year 2000 a small number of state and collective farms have been privatised and farm organisations and water users associations have been established. The thesis deploys political theory, social theory and new institutional economics to analyse and examine institutions and institutional change and to analyse local level transformations. Particular attention is given to key stakeholders in the agricultural sector and in water management organisations at the local and provincial levels and to how they implemented the change. The main findings of the thesis first, confirm that institutions reduce negotiation and discourse costs by providing a structure for contention and accommodation. However, the findings indicate that institutions also have negative effects, because they reflect and reinforce old power relations and therefore can be exploited to serve the interests of privileged former stakeholders. The second main finding is that institutions and their ability to effect change is determined by the power of influential stakeholders, who enable or reject change. The findings of the thesis are important for those developing strategies for the creation of bottom-up movements, and also for the social engineering and reengineering of larger institutions and organisations. The findings will be especially significant for those involved in land and water reform processes and in the privatisation of governmental industries.
32
Pérez, Sáez Juan G. "Recruiting the Water Quality Trader: Do Socioeconomic Variables and Levels of Trust Matter?" The Ohio State University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=osu1397745413.
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33
Noyes, Thomas Kelly. "Nutrient levels and biostimulation in the lower Colorado River/reservoir system". Thesis, The University of Arizona, 1985. http://etd.library.arizona.edu/etd/GetFileServlet?file=file:///data1/pdf/etd/azu_e9791_1985_104_sip1_w.pdf&type=application/pdf.
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34
Bognäs, Désirée. "To save water or not? : A study of water scarcity at multiple levels, and people's attitudestowards it in Bangalore, India". Thesis, Stockholms universitet, Institutionen för naturgeografi och kvartärgeologi (INK), 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-59320.
Testo completoAbstract (sommario):
In a situation where population growth and development is to be sustained throughnaturally limited water resources, something needs to be done to either render waterusage more effective or make more water available. This is the situation in Bangalore Urban District (BUD), an ever growing city lying far from perennial water sources. This thesis presents the water situation in BUD, and aims to analyze the current status of water resources on multiple levels in BUD. Further the aim is to look at people‘s attitudes towards water scarcity. The methods used are literature studies and semistructured interviews. The study shows that there is a lack of water in relation to the population on basin level, creating the perquisites for water scarcity. Even so, the water stress on city level does not seem to be a direct effect off the water scarcity on basin level, but rather a result of inefficient governance and inadequate infrastructure. This means that to solve the issue, the governing entities in BUD must firstly look at improving the situation on city level rather than focusing on Water Supply Managementon basin level. The perception of this problem varies among people in BUD, and the perception of water stress in relation to the most favorable incentives to care which are a combination of personal and common good incentives, can affect household‘s water behavior. The significance of these results is that people‘s attitudes towards water resources will affect how they handle and use water. Through further research this knowledge can be vital to understanding how to achieve behavioral changes that can lover usage in a growing city like Bangalore.
35
Joyce, William Lucas. "Examining Pathways for Water Loss from Mountain Lake, Giles County, Virginia". Thesis, Virginia Tech, 2012. http://hdl.handle.net/10919/76804.
Testo completoAbstract (sommario):
Located in Giles County, Virginia, Mountain Lake has a documented history of dramatic water level fluctuations. Previous water balance studies have documented that the main cause of water loss is outflow to groundwater. However, the flow paths of water exiting the lake are unknown. This study applied hydrologic, geophysical, and dye tracer methods to examine the pathways for water loss and the possible geologic controls on these flow paths.
Continuous lake level monitoring data show seasonal trends of draining and filling over a three year period. Electrical resistivity profiles suggest the presence of a large low-resistivity zone beneath the northern end of the lake. A dye tracer study yielded limited positive results, but dye detection in one stream and within the lake suggest complex flow dynamics. The most likely reasons for the lack of dye recovery include dilution of the dye during lake recovery, seepage of water below monitoring site locations, or formation of a temporary seal in the depressions created by influx of sediment during periods of lake bed exposure.Master of Science
36
Guldan, Nathan M. "Relationships between groundwater recharge dates, nitrate levels, and denitrification in a central Wisconsin watershed /". Link to Abstract, 2004. http://epapers.uwsp.edu/abstracts/2004/Guldan.pdf.
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Allee, Rachel Donovan Deborah Anne. "The effects of anoxic conditions on thermal tolerance and stress protein levels in four local bivalves /". Online version, 2010. http://content.wwu.edu/cdm4/item_viewer.php?CISOROOT=/theses&CISOPTR=323&CISOBOX=1&REC=4.
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38
Bartkowiak, Brandon Michael. "Ground-water flow modeling of the impact of quarry dewatering on water levels in the fractured carbonate aquifer, Kelleys Island, Ohio". The Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=osu1245339592.
Testo completo
39
Cuddy, Alan Stuart 1954. "The effects of Columbia River stage fluctuations on ground-water levels near Richland, Washington". Thesis, The University of Arizona, 1988. http://hdl.handle.net/10150/191976.
Testo completoAbstract (sommario):
An analysis of time-series data from wells monitoring deep, confined aquifers near Richland, Washington was conducted to quantify the effects of Columbia River stage fluctuations on water levels in these aquifers. Water levels respond to long-term time trends, atmospheric pressure fluctuations, earth tides, and river stage fluctuations. The effects of the river were isolated and quantified using spectral analysis and multiple regression. Water levels in the shallow (<600 m) aquifers responded to hydraulic communication with the river and loading by the river. The deeper aquifers (>600 m) responded only to loading. The results gave support to current estimates of hydraulic conductivity and specific storage of the units. Multiple regression and spectral analysis were found to be effective in identifying and quantifying causes of water-level fluctuations.
40
Altman, Danielle Marcelle. "The use of imagery to optimize anxiety levels in female intercollegiate water polo players". CSUSB ScholarWorks, 2000. https://scholarworks.lib.csusb.edu/etd-project/1607.
Testo completo
41
Waldron, Miranda Elizabeth. "The importance of water levels in the management of the Klein River Estuary, Hermanus". Master's thesis, University of Cape Town, 1987. http://hdl.handle.net/11427/15848.
Testo completoAbstract (sommario):
Bibliography: pages 85-89.The Klein River Estuary is situated at Hermanus in the Western Cape, South Africa. The estuary mouth is normally closed by a sand berm during the summer and open to the sea during the wetter winter months. The estuary forms a shallow lagoon which is becoming increasingly popular for recreational activities. Several management problems have arisen which are now becoming important with the increase in recreational pressure. The main problems are: uncertainty about appropriateness of water levels, marine sand influx and accumulation, flooding of low lying developments, flooding of agricultural lands, decrease in fish catches and indecision about the ideal position of the estuary mouth in the sand berm. This study concentrates mainly on the effects of different possible water levels. The conclusion is that the estuary water level should be permitted to rise at least as high as the highest level investigated. The estuary should be allowed to breach the sand berm. Developments on low lying land, prone to flooding, should be prohibited and only those structures which would not be damaged by flooding should be allowed in such areas.
42
Hill, Gregory J. "Examining Movement and Habitat Selection of Everglades Fishes in Response to Seasonal Water levels". FIU Digital Commons, 2017. http://digitalcommons.fiu.edu/etd/3209.
Testo completoAbstract (sommario):
Fish distribution patterns and seasonal habitat use play a key role in the food web dynamics of aquatic ecosystems, including the Florida Everglades. In this study I examined the fine scale habitat shifts and movements of spotted sunfish, Lepomis punctatus across varying seasons and hydrologic conditions using in-situ field enclosures and Passive Integrated Transponder (PIT) systems. Data on fish use of three dominant Everglades marsh habitats and activity level were recorded continuously from January to August, 2015. Fish were more active and had the highest use of higher elevation habitats when water levels rose during an experimental reversal in mid-April. Fish activity was higher at increasing water levels relative to decreasing. Fish activity also varied with the rate of change, with the highest activity occurring during rapid increases in depth. Findings from this study provide insight on how fish response to changing water levels may affect foraging for wading birds, a key performance measure for Everglades restoration.
43
Whittaker, Thomas E. "Lake-Level Fluctuations in the Fryxell Basin, Eastern Taylor Valley, Antarctica". Fogler Library, University of Maine, 2004. http://www.library.umaine.edu/theses/pdf/WhittakerTE2004.pdf.
Testo completo
44
Bound, Alice Jayne. "The development and use of satellite remote sensing techniques for the monitoring and hydrological modelling of the Sudd Marshes". Thesis, University College London (University of London), 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.313982.
Testo completo
45
Jones, Cullen Brandon. "Groundwater-Surface Water Interactions near Mosier, Oregon". PDXScholar, 2016. https://pdxscholar.library.pdx.edu/open_access_etds/3414.
Testo completoAbstract (sommario):
The town of Mosier, Oregon, is located near the east, dry end of the Columbia River Gorge, and the local area is known for cherry orchards that rely heavily on groundwater for irrigation. The CRBG groundwater system in Mosier has experienced groundwater declines of up to 60 meters due to over-pumping and or commingling. Declining groundwater levels have led to concerns over the sustainability of the resource, as it is the principle water source for irrigation and domestic use. Despite numerous previous studies of groundwater flow in CRBG aquifers here and elsewhere in the Columbia River basin, an aspect that has received relatively little attention is the interaction between groundwater and surface waters at locations where interflow zones are intersected by the surface waters.
The objective of my research is to investigate how CRBG interflow zone exposures in Mosier Creek may be controlling groundwater elevations in the area. The methods used include: (1) geochemical analysis of well cuttings and detailed geologic mapping along area streams to identify interflow zones of individual CRBG flows, (2) analysis of stream discharge data and groundwater elevation data to confirm exchange of groundwater and surface waters, and (3) collection and analyses of 31 water samples from area wells, streams, and springs, to determine if waters from individual CRBG aquifers can be hydrochemically identified and to further constrain understanding of surface and groundwater interactions.
My study confirms that the general elevation of the Pomona Member and Basalt of Lolo interflow zone creek exposure is coincident with the elevation where a change in slope of the decline trend in 2004 is seen in Mosier area well hydrographs. Furthermore, the results of stream discharge data indicated a close connection between drawdown from groundwater pumping during irrigation season and groundwater- surface water interaction. At the time of drawdown in the upper-most CRBG aquifer (Pomona), the stream transitions from gaining to losing water into the groundwater system.
Elemental chemistry data indicates the Frenchman Springs Sentinel Gap aquifer waters are the most evolved waters in this study. Stable isotopic data reinforced this determination as the Sentinel Gap waters are the lightest, or most negative, with regard to δD and δ18O. Sentinel Gap samples were more depleted than other aquifer samples by 4.38 to 6.89 0/100 for δD and 0.39 to 0.59 0/100 for δ18O. The results of the general chemistry and isotope data reveal a more evolved chemical signature in lower watershed groundwater versus a less evolved signature for waters from wells located higher up on the Columbia Hills anticline. This was interpreted to be the result of the major structural features in the area providing for a more regional pathway of recharge in lower watershed groundwaters, versus a more local source of recharge for upper watershed groundwaters. There was also a pronounced commingled signature in the elemental ratios of lower watershed aquifer waters. The suspected mechanism of recharge to lower watershed wells is through younger Cascadian deposits upslope from the local watershed.
The findings of this study reveal the importance of a detailed understanding of CRBG stratigraphy and its relation to surface waters, especially for other areas within the Yakima Fold Belt or Oregon and Washington. Studies that do not consider the influence that individual CRBG flows can have on groundwater-surface water interactions, and the groundwater system as a whole, run the risk of improperly assessing the groundwater resource for a region.
46
Semon, Mande 1957. "Interplot and intraplot border effects on maize genotypes under two levels of moisture availability". Thesis, The University of Arizona, 1988. http://hdl.handle.net/10150/276817.
Testo completoAbstract (sommario):
The performance of three maize (Zea mays L.) hybrids, grown under two irrigation levels, was used to investigate the effects of soil moisture competition between adjacent plots, the transmission of these effects into multi-row adjacent plots and types of multi-row plots and plot borders most effective in shielding from these interplot competition effects. On the basis of grain yield, competition effects intended to the second rows of five-row plots necessitating more than five-row plots to accurately evaluate the full transmission of interplot competition effects into adjacent plots. Evaluation of genotypes in one-row plots all with the same common border row genotype to make them three-row plots would be more suitable for evaluation of relative competitiveness for soil moisture under soil moisture stress conditions compared to no border rows or border rows of the same genotype being evaluated.
47
Ripley, Dana Cameron. "Changes in Soil Salinity Levels with the Use of Recycled Water on Cool Season Vegetables". DigitalCommons@CalPoly, 2013. https://digitalcommons.calpoly.edu/theses/1111.
Testo completoAbstract (sommario):
Agricultural production in Monterey County, California is a multi-billion dollar industry. Near the coast, seawater intrusion has threatened to degrade the groundwater quality due to over-pumping of the aquifer. The Monterey Regional Water Pollution Control Agency (MRWPCA), in partnership with the Monterey County Water Resources Agency, has provided recycled water since 1998 to over 12,000 acres of prime agricultural farmland in the northern Salinas Valley in an effort to reduce groundwater removal. The dominant soil types in the region are clay loam and clay soils, which are both susceptible to sodium (Na) accumulation and water infiltration problems. Recycled water blended with well water is used to irrigate cool season vegetables (i.e., artichokes, broccoli, Brussels sprouts, celery, cauliflower, and lettuce) and strawberries. A long-term study was implemented by MRWPCA to monitor salinity levels in commercial vegetable fields because of grower concerns that salts in the recycled water would have long term effects on soil quality. Accumulation of salts over time would make the soil less productive. Soil salinity levels were monitored at three Control and three Test Sites beginning in the spring of 2000. The Control Sites received well water, and the adjacent Test Sites received an approximate 2:1 blend of recycled and well water, respectively. Control and Test Sites were paired based on location to compare the same soil, crop, drainage systems, and farming practices. The soil was sampled three times per year from all sites: spring (before planting), mid-summer after harvest of the first crop, and late fall after the second crop harvest. Composites of four cores were collected at each site from the zero to 36-inch depth at 12-inch intervals. Each 12-inch interval soil sample was analyzed for pH, electrical conductivity (ECe), extractable cations (Na+, Ca2+, Mg2+, and K+) and extractable anions (Cl-, NO3-, and SO4-). After 10 years of monitoring, the data showed that using recycled water blended with well water at the Test Sites increased the ECe of the soil profile from 2.1 to 2.5 dS/m and increased the sodium adsorption ratio (SAR) from 3.0 to 3.9. The data also showed that using well water at the Control Sites increased the ECe of the soil profile from 1.4 to 2.6 dS/m and the change in SAR was negligible. The Test and Control Sites were significantly different for ECe and SAR, which was expected considering a higher salt content in the recycled water compared to the well water. The significant differences for ECe and SAR were associated with the significant differences in soil Na+ levels between the Test and Control Sites. The SAR and ECe of soil samples from all sites were in a range acceptable for vegetable production. The use of recycled water for irrigation of cool season vegetables and strawberries in the study area has not shown an indication of degraded soil productivity. Based on vegetable production and the slow increase of salts in the soil, recycled water can be used for long-term irrigation with proper management.
48
Eglington, Sarah. "Managing water levels on wet grasslands for breeding waders : the use of shallow wet features". Thesis, University of East Anglia, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.504849.
Testo completoAbstract (sommario):
Lowland wet grasslands support a wide range of biodiversity and provide important breeding grounds for many wader species. However, extensive drainage and conversion to arable cropping or intensively managed grassland has greatly reduced the abundance and quality of this habitat across Europe, and caused severe declines in many of the associated waders. Recent agri-environment initiatives provide opportunities to restore wet grasslands, but little is known about the key features necessary to support breeding waders and how these may conflict with commercial farming practises. For breeding waders, the re-introduction of water into the habitat is critically important, and this thesis examines methods of creating and managing within-field wet features and surface water, their impact on the distribution and breeding success of lapwing Vanellus vane/Ius, and the extent to which they are compatible with agricultural operations in the Broads, eastern England. Breeding lapwing are attracted to areas with extensive surface flooding. However, most surface water dries out during the breeding season. The creation of managed shallow wet features allowed water to be retained throughout the breeding season. Fields with higher wet feature densities attracted significantly more nesting lapwing and foraging chicks, and chick condition was significantly improved. Invertebrate biomass and chick foraging rates were higher in wet features than in the surrounding grazing marsh. Neither nest or chick predation rates were related to the proximity of wet features, but predation rates declined with density of lapwing in the vicinity, suggesting an influence of collaborative nest and brood defence. Farmers were keen to enter agri-environment schemes and to use shallow wet features, provided the design was not too complex. Wet feature installation is relatively simple, but maintaining sufficient water levels is critical, especially in the face of increasingly unpredictable water supplies associated with climate change. If managed correctly, shallow wet features offer a tool that may be both effective at improving breeding wader populations and practicable for commercial grazing marsh management.
49
More, Priyanka Ramesh. "Using Machine Learning to predict water table levels in a wet prairie in Northwest Ohio". Bowling Green State University / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1535334208410497.
Testo completo
50
Oliveira, Nuno Miguel. "Technique and muscle activity of the water polo eggbeater kick at different levels of fatigue". Thesis, University of Edinburgh, 2014. http://hdl.handle.net/1842/15782.
Testo completoAbstract (sommario):
The eggbeater kick is a skill used frequently in water polo and synchronized swimming to elevate the upper body for shooting, passing, blocking or compete with the opponent for position in the water. The hips, knees, and ankles are involved in creating favourable orientations of the feet so that propulsive forces in the vertical direction can be created. Literature reporting the technique of the eggbeater kick is scarce and limited to description of kinematics or muscle activity. The relationship of the kinematics to the demands on specific muscles has not been established. The purpose of this study was to analyze the kinematics and muscle activity of the water polo eggbeater kick in fatigued and unfatigued states to provide foundational knowledge on which training programs can be based. Twelve water polo players were tested executing the eggbeater kick in the vertical position while trying to maintain as high a position as possible for the duration of the test. The test was terminated when the player could not keep the top of the sternum marker above water. Anthropometric data were collected using the ‘eZone’ method. Three dimensional coordinates for the lower limbs and two dimensional coordinates of the above water top of the sternum marker were obtained. Surface electromyography recorded the muscle activity of the Tibialis Anterior, Rectus Femoris and Biceps Femoris muscles on both legs. Differences between fatigued and unfatigued conditions and between dominant and nondominant sides were tested using a two factor ANOVA with repeated measures. Differences within subjects were also investigated on a subject by subject basis with regard to muscle activity. Results indicated differences for kinematic and muscle activity variables between fatigue levels. The amplitude of anatomic angles and speed of the feet decreased with fatigue. Significant differences were found between dominant and non-dominant sides for the ankle motion. The non-dominant ankle was more inverted and adducted than the dominant ankle during the knee flexion phase of the cycle. The Rectus Femoris muscle had consistent patterns across subjects, while Tibialis Anterior and Biceps Femoris muscles were more subject specific in their responses. The Rectus Femoris and the Biceps Femoris have an agonist/antagonist relationship during knee flexion and extension. The Tibialis Anterior was active for long periods in the cycle while dorsiflexing and inverting the foot. As a consequence activity in these muscles decreased with fatigue. These findings point towards the necessity for players and coaches to address specific motions and muscles during the training of the eggbeater technique. Future work should focus on developing eggbeater kick training programs that address specific strength and flexibility.