Saturated and near-saturated surface soil hydraulic properties influence the partition of rainfall and snowmelt into infiltration and runoff. The goal of this study was to characterize near-saturated surface soil hydraulic properties and water-conducting porosity in sloping landscapes. The specific objectives included exploration of tension and double-ring infiltrometers for estimation of soil hydraulic properties in sloping landscapes, development of an improved method for determining water-conducting porosity, and the application of these methods in characterizing soil hydraulic properties and water-conducting porosity under three land use. Water infiltration from a double-ring infiltrometer and a tension infiltrometer at water pressures between -2.2 and -0.3 kPa was measured in a cultivated field with 0, 7, 15, and 20% slopes at Laura and under three land use (native grass, brome grass and cultivated) at St. Denis in Saskatchewan, Canada. Three-dimensional computer simulation studies were also performed for tension infiltrometer with various disc diameters, water pressures, and surface slopes. Steady infiltration rates and estimated field-saturated hydraulic conductivity (Kfs), hydraulic conductivity-water pressure relationship (K(h)), and inverse capillary length parameter were compared for different slopes and land use. These parameters were not significantly different (p<0.05) among slopes. For specific K(h) functions, a new analytical solution was developed and compared with existing methods for calculating water-conducting porosity. The new method reliably determined water-conducting porosity of surface soils and gave consistent results, regardless of the width of water pressure ranges. At the -0.3 kPa water pressure, hydraulic conductivity of grasslands was two to three times greater than the cultivated lands. Values of inverse capillary length parameter were about two times and values of Kfs about four times greater in grasslands than in cultivated fields. Water-conducting macroporosity of grasslands and cultivated fields were 0.04% and 0.01% of the total soil volume, respectively. Over 40% and 50% of the total water flux at -0.06 kPa water pressure was transmitted through macropores (pores > 1×10-3 m in diameter) of the cultivated land and the grasslands, respectively. Experimental and simulation results of this study indicated that both tension and double-ring infiltrometers are suitable for characterization of saturated and near-saturated surface soil hydraulic properties in landscapes up to 20% slope. The new method can be used to characterize water-conducting porosity from in situ tension and double-ring infiltrometers measurements more adequately and efficiently than the existing methods. Application of these methods for three land use indicated that land use modified surface soil hydraulic properties and consequently may alter the water balance of an area by affecting the partition between, and relative amount of infiltration and surface runoff.

Saturated and near-saturated surface soil hydraulic properties influence the partition of rainfall and snowmelt into infiltration and runoff. The goal of this study was to characterize near-saturated surface soil hydraulic properties and water-conducting porosity in sloping landscapes. The specific objectives included exploration of tension and double-ring infiltrometers for estimation of soil hydraulic properties in sloping landscapes, development of an improved method for determining water-conducting porosity, and the application of these methods in characterizing soil hydraulic properties and water-conducting porosity under three land use. Water infiltration from a double-ring infiltrometer and a tension infiltrometer at water pressures between -2.2 and -0.3 kPa was measured in a cultivated field with 0, 7, 15, and 20% slopes at Laura and under three land use (native grass, brome grass and cultivated) at St. Denis in Saskatchewan, Canada. Three-dimensional computer simulation studies were also performed for tension infiltrometer with various disc diameters, water pressures, and surface slopes. Steady infiltration rates and estimated field-saturated hydraulic conductivity (Kfs), hydraulic conductivity-water pressure relationship (K(h)), and inverse capillary length parameter were compared for different slopes and land use. These parameters were not significantly different (p<0.05) among slopes. For specific K(h) functions, a new analytical solution was developed and compared with existing methods for calculating water-conducting porosity. The new method reliably determined water-conducting porosity of surface soils and gave consistent results, regardless of the width of water pressure ranges. At the -0.3 kPa water pressure, hydraulic conductivity of grasslands was two to three times greater than the cultivated lands. Values of inverse capillary length parameter were about two times and values of Kfs about four times greater in grasslands than in cultivated fields. Water-conducting macroporosity of grasslands and cultivated fields were 0.04% and 0.01% of the total soil volume, respectively. Over 40% and 50% of the total water flux at -0.06 kPa water pressure was transmitted through macropores (pores > 1×10-3 m in diameter) of the cultivated land and the grasslands, respectively. Experimental and simulation results of this study indicated that both tension and double-ring infiltrometers are suitable for characterization of saturated and near-saturated surface soil hydraulic properties in landscapes up to 20% slope. The new method can be used to characterize water-conducting porosity from in situ tension and double-ring infiltrometers measurements more adequately and efficiently than the existing methods. Application of these methods for three land use indicated that land use modified surface soil hydraulic properties and consequently may alter the water balance of an area by affecting the partition between, and relative amount of infiltration and surface runoff.

The underlying objective of this research is to improve the overall understanding of how spatial and temporal variability in macroporosity and soil hydraulic properties in the shallow subsurface influence the long term mobility of agricultural nutrients, and specifically the movement of liquid swine manure, in macroporous, tile drained soils. The principal motivation for the work was to provide insight into dynamic nutrient mobility in this type of agricultural environment in order to guide both the efficiency and environmental sustainability of nutrient management practices. The results of this work facilitate the advancement of our conceptual understanding and our ability to simulate preferential flow and transport in structured agricultural soils that are subject to seasonal hydrologic patterns similar to those found in the humid continental climate of southwestern Ontario

A patterned, partially-treed, fen in the mid-boreal region of central Saskatchewan was the site of renewed hydrological research from 2002 to 2004. Hydraulic conductivity, transmissivity, and storativity were determined through use of a surface loading test, pumping tests, and an enclosed field drainage test. None of these field tests have been previously described in the literature as having been used in peat environments. The combined results of field and laboratory drainage tests were used to obtain a general storativity with water table depth relationship in the upper peat layer. The hydraulic conductivity, measured with slug tests, the loading test, and pumping tests, is high near the surface, declining greatly with depth. These previously untested field methods have the advantage of representing volumes of peat from tenths of a meter to cubic meters. </p>Characterization of the hydrology of the peatland involved year round observations of water table, piezometric head, peat surface elevations, frost depth and peat temperatures. Fluctuations of the water table, and soil moisture changes produce changes in effective stress that lead to volume change in the highly compressible peat. This is particularly important for sites with thick peat deposits. Independent compressibility estimates were as high as 10-5 N/m2 in the upper peat. At three fen sites, changes in peat thickness were estimated from monthly estimates of effective stress change, using year round hydrological observations, and compared to measured annual peat thickness changes. Water table changes causing soil moisture changes, and freeze-thaw processes, explained the majority of peat surface movements.

This thesis research consists of two separate studies. The first study presents the assessment and representation of the effects of soil macropores on the soil hydraulic properties in land surface models for more accurate simulations of soil moisture and surface hydrology. Hydraulic properties determine the soil water content and its transport in the soil. They are provided in most current climate models as empirical formulas by functions of the soil texture. Such is not realistic if the soil contains a substantial amount of macropores. A two-mode soil pore size distribution is incorporated into a land surface model and tested using an observational dataset at a tropical forest site with aggregated soils. The result showed that the existence of macropores greatly affects the estimation of hydraulic properties. Their influence can be included in land models by adding a second function to the pore-size distribution. A practical hydraulic scheme with macropore considerations was proposed given that the existing schemes are not applicable for large-scale simulations. The developed scheme was based on the physical attributes of the water in soil capillary pores and the statistics of several global soil databases. The preliminary test showed that it captures part of soil macropore hydraulic features without sacrificing the estimation accuracy of hydraulic properties of water in soil matrix. The second study presents the development of an integrated land/ecosystem model by combining the advanced features of a biophysically based land model, the Community Land Model, and an ecosystem biochemical model. The results from tests of the integrated model at four forest sites showed that the model reasonably captures the seasonal and interannual dynamics of leaf area index and leaf nitrogen control on carbon assimilation across different environments. With being coupled to an atmospheric general circulation model (AGCM), the integrated model showed a strong ability to simulate terrestrial ecosystem carbon fluxes together with heat and water fluxes. Its simulated land surface physical variables are reasonable in both geographic distribution and temporal variation with considering the interactive vegetation parameters.

Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniversitet, 2009. / Härtill 4 uppsatser.

An analytical model is presented for the analysis of pulse interference tests conducted in a fractured porous medium with connection to a free surface boundary at the water table. The solution is applicable to open borehole pulse interference tests due to the accommodation of multiple horizontal fractures intersecting each wellbore and a connection from the uppermost horizontal fracture to a free surface boundary. The solution is derived using the Laplace transform method and evaluation of the solution is performed by numerical inversion using the Talbot algorithm. Based on an informal sensitivity analysis, unique values for transmissivity, storativity, specific storage, vertical hydraulic conductivity and specific yield are predicted over a range of realistic values for these parameters. The analytical model is used to analyze slug tests and pulse interference tests conducted in a fractured gneiss formation. The results of these tests are compared to long-term pumping tests to identify the effect of measurement scale on transmissivity, storativity, vertical hydraulic conductivity and specific yield obtained in a fractured rock setting. Scale artefacts relating to measurement or analysis methods are minimized through the use of consistent well configurations in each of the applied hydraulic testing methods. The geometric mean estimates of transmissivity and storativity are shown to vary by less than an order of magnitude from local-scale tests to long-term pumping tests. The geometric mean specific yield result from a series of pulse interference tests that samples both highly fractured and poorly fractured portions of the rock formation approximates the long-term pumping test estimate of specific yield. The geometric mean result for vertical hydraulic conductivity decreases by approximately 1.5 orders of magnitude from the slug test to pumping test scale; however, pulse interference tests conducted on highly fractured portions of the formation produce vertical hydraulic conductivity estimates that are within a half order of magnitude of the long-term pumping test results. This suggests that the performance of pulse interference tests on a highly fractured portion of a rock formation may be a less time-intensive alternative to large-scale pumping tests in the determination of vertical hydraulic conductivity. / Thesis (Master, Civil Engineering) -- Queen's University, 2011-06-24 19:29:52.743

<p>&nbsp / Characterisation of fractured rock aquifers is important when dealing with groundwater protection and management. Fractures are often good conduits for water and contaminants, leading to high flow velocities and the fast spread of contaminants in these aquifers. A cost effective methodology is required for the characterisation of the role of individual fractures contributing to flow to boreholes in fractured rock aquifers. Literature shows that some of the conventional methods used to characterise hydraulic properties in fractured rock aquifers are expensive, complicated, time consuming and are associated with some disadvantages such as over-or under- estimations of flow rates. iii This thesis evaluates the use of Fluid Electrical Conductivity (FEC) logging in fractured rock aquifers. This FEC data are compared to various traditional methods used to determine aquifer hydraulic properties applied at the Franschhoek and Rawsonville research sites. Both these sites were drilled into the fractured rock Table Mountain Group (TMG) Aquifer, forming one of the major aquifers in South Africa.</p>

<p>Coal provides for 77% of South Africa&rsquo / s primary energy needs and is therefore a major resource that supports the socio-economic needs of South African citizens. Power stations are the major consumers of coal in South Africa and produces electricity from burned coal. The burning of coal produces a large volume of ash that is disposed in the form of ash dump systems. The ash&nbsp / dump system is treated with high salinity process water from the power station for dust suppression. The process water contains salts due to evaporation processes from the recirculation&nbsp / &nbsp / of&nbsp / water in the cooling water system. Various studies to evaluate the sustainability of the ash dump system as a sustainable salt sink were therefore conducted. This study aimed to develop a conceptual model for the ash dump system by evaluating the movement of the process water trough the ash dump and the impacts it might have on the underlying weathered dolerite aquifer. This was achieved by evaluating the hydraulic and transport properties of the ash dump system. An initial site conceptual model was first established prior to the application of the hydraulic&nbsp / and transport methods. The initial conceptual model was based on the literature, previous reports and an initial site walk over. Known and tested hydraulic and transport methods were applied&nbsp / n bo.th field and laboratory scale for the saturated part of the ash dump system. The laboratory experiments comprised of column and core experiments. These methods assisted in&nbsp / parameter estimation of hydraulic and transport properties and also assisted in the planning of the field experiments. The field experiments were conducted in the form of slug tests, tracer&nbsp / dilution and natural gradient divergent tracer test experiments. The combined laboratory and field experiments provided statistically significant values that were then used as inputs into the&nbsp / conceptual model. Field experiments were also applied to a surrogate aquifer that represented the underlying shallow weathered dolerite aquifer of the ash dump system. The components of&nbsp / the updated conceptual model identified and investigated include the physical environment, the calculated hydraulic and transport properties.The ash dump can be conceptualized as a 20 to&nbsp / &nbsp / 30 meter high heap of consolidated clay size ash&nbsp / particles built on top of an underlying shallow weathered dolerite aquifer. The ash dup is directly connected to the underlying weathered&nbsp / dolerite aquifer. The saline water within the saturated zone has the ability to move through the ash dump system with hydraulic conductivities ranging between 10-1-10- 2 m/day, with flow&nbsp / velocities of 7-8m/day and effective porosities of 1%-2%. The hydraulic properties of the ash dump are, amongst others, controlled by the ash geology, contact time of the process water with the&nbsp / sh and show a significant reduction in hydraulic conductivity over time, before reaching a steady state. The transport properties are controlled by advection and spreading in available&nbsp / pathways. Results for the surrogate underlying fractured rock aquifer show flow velocities of 31m/day and an effective porosity of 1%.This suggests that the underlying weathered dolerite&nbsp / aquifer is vulnerable to process water contamination from the ash dump system. The study illustrates the importance of a site conceptual model before the application of investigative&nbsp / methods. Hence having a site conceptual model provides an excellent platform for hydraulic and transport estimation. The development of a site conceptual model enhanced the&nbsp / understanding of flow and transport movement of the processed&nbsp / water trough the ash dump, it also assisted as a beneficial tool to enhance ash dump management.</p>

The underlying objective of this research is to improve the overall understanding of how spatial and temporal variability in macroporosity and soil hydraulic properties in the shallow subsurface influence the long term mobility of agricultural nutrients, and specifically the movement of liquid swine manure, in macroporous, tile drained soils. The principal motivation for the work was to provide insight into dynamic nutrient mobility in this type of agricultural environment in order to guide both the efficiency and environmental sustainability of nutrient management practices. The results of this work facilitate the advancement of our conceptual understanding and our ability to simulate preferential flow and transport in structured agricultural soils that are subject to seasonal hydrologic patterns similar to those found in the humid continental climate of southwestern Ontario