Henry R. Hirsch. / "October 15, 1961." "...presented to the Department of Physics, Massachusetts Institute of Technology, in partial fulfillment of the requirements for the degree of Doctor of Philosophy." "Reprinted from Journal of the Optical Society of America, vol. 51, no. 11, 1192-1202, November, 1961." / Army Signal Corps Contract DA36-039-sc-78108, Department of the Army Task 3-99-20-001 and Project 3-99-00-000.

Adrian C. Melissinos, Sumner P. Davis. / "November 10, 1958." "Reprinted from The physical review, v.115, no.1, July 1, 1959" / Includes bibliographical references. / Army Signal Corps Contract DA36-039-sc-78108. Dept. of the Army Task 3-99-20-001 and Project 3-99-00-000.

[by] Joseph T. Eisinger [and] Benjamin Bederson. / Portion of a thesis. "January 28, 1952." / Bibliography: p. 32. / Army Signal Corps Contract No. DA 36-039 sc-100. Project No. 8-102B-0. Dept. of the Army Project No. 3-99-10-022.

The Grand River Watershed, in southern Ontario, is home to approximately 900,000 people and one of the fastest growing regions in Canada; specifically, in the urban areas of Guelph, Cambridge, Kitchener, and Waterloo. This growth strains the watershed’s capacity to supply adequate water resources to these municipalities, as well as manage the waste-water treatment effluent discharged from them. Nowhere in the watershed is this juxtaposition in water resource function more apparent than at the city of Brantford, with a population of approximately 100,000 people. Located forty-two kilometers downstream from the major urban areas, Brantford is unique in the watershed in that it obtains its entire municipal water supply directly from the Grand River, into which the upstream municipalities discharge 77% of the total waste-water treatment plant effluent emitted to the watershed. One contaminant of concern is nitrate, which, for decades, has been linked to numerous human and aquatic health complications. The input of nitrate from these upstream WWTP’s is considerable; the WWTP’s have a combined flow rate of 2.3 m3s-1, and a mean nitrate concentration of 10.4 mg N·L-1 (data from Anderson, 2012). As a comparison, the Nith River, the largest tributary to the Grand River between Cambridge and Brantford, has a summer baseflow of 2.9 m3s-1 and, from 2000 to 2004, had a mean nitrate concentration of 4.4 mg N·L-1 (Cooke, 2006). Brantford, in addition to treating their water supply, relies on the dilution of in-stream nitrate from groundwater that is thought to discharge along the Grand between Cambridge and the Brantford municipal water intake. This 40-km reach of the Grand River is colloquially referred to as either the discharge reach or the recovery reach. Recent data from various authors indicate that groundwater may not always act to dilute in-stream nitrate from upstream WWTPs (Encalata, 2008; Pastora, 2009; Rosamond 2009). The main objective of the research completed in this thesis was to refine the conceptual model of groundwater/surface water interaction along the Grand River between Cambridge and Brantford. Refinement of this conceptual model was accomplished in two parts. First, groundwater discharge, from bank seepage and direct discharge through the riverbed, was located using a variety of methods; a simple reconnaissance survey by canoe, a FLIR thermography survey, drag probe surveys, and a temperature profiling method. Then domestic wells, seeps, tributaries, riverbed discharge, and WWTP effluent were sampled to geochemically characterize inputs to the Grand River.

With the advent of more powerful, less expensive computing resources, more and more attention is being given to Monte Carlo techniques in design application. In many circles, stochastic solutions are considered the next best thing to experimental data. Statistical uncertainties in Monte Carlo calculations are typically determined by the first and second moments of the tally. For certain types of calculations, there is concern that the uncertainty estimate is significantly non-conservative. This is typically seen in reactor eigenvalue problems where the uncertainty estimate is aggravated by the generation-to-generation fission source. It has been speculated that optimization of the random walk, through biasing techniques, may increase the non-conservative nature of the uncertainty estimate. A series of calculations are documented here which quantify the reliability of the Monte Carlo Neutron and Photon (MCNP) mean and uncertainty estimates by comparing these estimates to the true mean. These calculations were made with a liquid metal fast reactor model, but every effort was made to isolate the statistical nature of the uncertainty estimates so that the analysis of the reliability of the MCNP estimates should be relevant for small thermal reactors as well. Also, preliminary reactor physics calculations for two different special isotope production test assemblies for irradiation in the Fast Flux Test Facility (FFTF) were performed using MCNP and are documented here. The effect of an yttrium-hydride moderator to tailor the neutron flux incident on the targets to maximize isotope production for different designs in different locations within the reactor is discussed. These calculations also demonstrate the useful application of MCNP in design iterations by utilizing many of the codes features. / Graduation date: 1992

pas de résumé

Surface mining of oil sands in northern Alberta requires stripping of saline-sodic shale overburden, which is typically placed in large upland overburden dumps. Due to the chemical nature of this shale, engineered soil covers must be constructed over the shale to support the growth of forest vegetation. A research site on South Bison Hill (SBH), a shale overburden dump at the Syncrude Canada Ltd. Mildred Lake Mine, has been used by researchers over the past decade to study the performance of a reclamation cover. This study was undertaken to improve the understanding of salt and moisture dynamics in the cover-shale system. In particular, the objective of this study was to develop an estimate of the net percolation rate through the cover soil and into the shale overburden. Stable isotope (ä2H and ä18O) measurements obtained from the pore water of soil samples were used to develop stable isotope profiles at various sampling locations along the slope and plateau of the SBH. Simulated profiles were then generated using 2D, finite element numerical modelling software and compared to the measured profiles. Model parameters were obtained from testing and the work of previous researchers. The model results revealed that the net percolation is greatest (32-50 mm/yr) for the plateau and mid-slope bench sample locations. Net percolation rates for sample locations on the slope were lower at 0-12 mm/yr. The results from the stable isotope modelling were utilized in a SO42- transport model to ascertain if calculated net percolation rates could explain measured salinity profiles. This modelling exercise revealed that calculated SO42- profiles are highly dependent on the assumed SO42- production rates in the shale, which is primarily attributed to pyrite oxidation. The model results showed the isotope-based net percolation rates could explain the measured SO42-profiles for a reasonable range SO42- production rates. The SO42- production rates calculated in the model were greatest for the plateau and mid-slope bench locations and lesser for the sloped locations. The model also showed that the mass of SO42- removed by interflow was minimal compared to the mass generated by pyrite oxidation and that net percolation is the dominant flushing mechanism at net percolation rates of 8 mm/yr or more.

Surface mining of oil sands in northern Alberta requires stripping of saline-sodic shale overburden, which is typically placed in large upland overburden dumps. Due to the chemical nature of this shale, engineered soil covers must be constructed over the shale to support the growth of forest vegetation. A research site on South Bison Hill (SBH), a shale overburden dump at the Syncrude Canada Ltd. Mildred Lake Mine, has been used by researchers over the past decade to study the performance of a reclamation cover. This study was undertaken to improve the understanding of salt and moisture dynamics in the cover-shale system. In particular, the objective of this study was to develop an estimate of the net percolation rate through the cover soil and into the shale overburden. Stable isotope (ä2H and ä18O) measurements obtained from the pore water of soil samples were used to develop stable isotope profiles at various sampling locations along the slope and plateau of the SBH. Simulated profiles were then generated using 2D, finite element numerical modelling software and compared to the measured profiles. Model parameters were obtained from testing and the work of previous researchers. The model results revealed that the net percolation is greatest (32-50 mm/yr) for the plateau and mid-slope bench sample locations. Net percolation rates for sample locations on the slope were lower at 0-12 mm/yr. The results from the stable isotope modelling were utilized in a SO42- transport model to ascertain if calculated net percolation rates could explain measured salinity profiles. This modelling exercise revealed that calculated SO42- profiles are highly dependent on the assumed SO42- production rates in the shale, which is primarily attributed to pyrite oxidation. The model results showed the isotope-based net percolation rates could explain the measured SO42-profiles for a reasonable range SO42- production rates. The SO42- production rates calculated in the model were greatest for the plateau and mid-slope bench locations and lesser for the sloped locations. The model also showed that the mass of SO42- removed by interflow was minimal compared to the mass generated by pyrite oxidation and that net percolation is the dominant flushing mechanism at net percolation rates of 8 mm/yr or more.

Nitrogen (N) contained in roots and rhizodeposits represents a significant input of crop residue-N into soil that is often unaccounted, despite its contribution to the total N budget and its influence on soil nutrient cycling. Utilizing 15N-labeling methodologies under controlled conditions, the goal of this research was to quantify the input of belowground N (BGN), including rhizodeposits and roots, to soil and to investigate the influence of BGN on soil N cycling processes from the major pulse and oilseed crop grown across the Canadian prairies—namely, field pea and canola, respectively. Using continuous 15N2 labeling, the input of fixed-N to rhizosphere soil from pea plants amounted to less than 2% of the total plant N assimilated via fixation. Nodulation and root 15N enrichment were positively related to rhizosphere 15N enrichment, suggesting that the relatively low input of fixed-N to soil was due to low N fixation in this system. Shoot 15N-labeling techniques enabled a higher 15N enrichment in roots; as a result, rhizodeposition was detected in the rhizosphere as well as the surrounding bulk soil. Rhizodeposition accounted for 7.6 and 67% of plant N and BGN, respectively, in mature pea. Temporal changes in the pattern of rhizodeposition were detected as evidenced by differing 15N enrichment in rhizosphere versus bulk soils. In comparison to pea, a higher proportion of BGN contributed to the total residue-derived N from canola. The higher quantity of N rhizodeposition by canola was related to greater root biomass. However, pea rhizodeposition contributed more to soil inorganic N pools; this was sustained over time, as a higher proportion of pea BGN contributed to the growth of a subsequent wheat crop. In addition, wheat uptake of residue-derived N was twice as much from belowground compared to straw residues. Whereas the abundance of denitrifying bacterial communities in the rhizosphere was uncoupled from rhizodeposition and denitrification enzyme activity (DEA), root-derived 15N correlated with DEA in pea and canola. This research highlights the importance of belowground inputs from differing crop species on N budgets and soil N cycling.

This thesis develops a methodology for mesoscale model verification and validation that is founded on the rigorous constraint imposed by the need to conserve both water mass and isotopes simultaneously. The isoWATFLOOD model simulates δⁱ⁸O in streamflow, which effectively reduces and constrains errors associated with equifinality in streamflow generation by improving internal parameterizations. The WATFLOOD model is a conceptually-based distributed hydrological model used for simulating streamflow on mesoscale watersheds. Given the model’s intended application to mesoscale hydrology, it remains crucial to ensure conceptualizations are physically representative of the hydrologic cycle and the natural environment. Stable water isotopes because of their natural abundance and systematic fractionation have the ability to preserve information on water cycling across large domains. Several coordinated research projects have recently focused on integrating stable water isotopes into global and regional circulation models, which now provides the opportunity to isotopically force land-surface and hydrological models. Where traditionally streamflows are the primary validation criteria in hydrological modelling, problems arise in remote and ungauged basins, or large watersheds where streamflows may not be well monitored. By streamflow validation alone, no insight is obtained on the internal apportioning and physical representation of sub-processes contributing to streamflow. The primary goal of this research is to develop alternative measures to parameterize mesoscale hydrological models in a physically-based manner, and to validate such models over large domains. This research develops improved model parameterizations that facilitate realistic runoff generation process contributions. The examination of runoff generation processes and the subsequent δⁱ⁸O of these processes are performed for two mesoscale watersheds: Fort Simpson, NWT and the Grand River Basin, ON. The isoWATFLOOD model is shown to reliably predict streamflow and δⁱ⁸O of streamflow, and simulates mesoscale isotopic fractionation associated with evaporation. In doing so, a more physically meaningful, robust modelling tool is developed that is practical for operational use. This research also contributes the first continuous record of δⁱ⁸O in streamflow that enables the visualization of spatial and temporal variability and dominant hydrologic controls within mesoscale watersheds.