Introduction: The movement of moisture and the simultaneous transfer of water and solutes in unsaturated porous media are problems of practical interest in ground water hydrology and soil physics. A large fraction of the water falling as rain on the land surfaces of the earth moves through unsaturated zone of soil during the subsequent processes of infiltration, drainage, evaporation, and absorption of soil -water by plant roots. A soil profile is characteristically nonuniform in its properties, nonisothermal, and may be nonrigid. Microorganisms and the roots of higher plants are a part of the system. This region is characterized by cylic fluctuation of water content as water is removed from the soil profile by evaportranspiration and replenished by recharge, irrigation, or rainfall. In unsaturated porous media the problem of movement and retention of water may be approached from (1) the molecular, (2) the microscopic, or (3) the macroscopic standpoint. In the molecular viewpoint theories of the mechanisms of flow and retention in terms of the behavior of water molecules are devised. At microscopic level a theory of flow treating the fluid in pores as a continuum and applying the principles of continuum mechanics to understand the detailed behavior of fluid within the pores is developed. The complicated pore geometry and consequent impossibility of specifying the boundary conditions on flow, preclude any practical progress by this appraoch. Since the behavior of individual molecules and the distributions of fluid velocity and pressure cannot be observed in porous media, a macroscopic theory of flow is needed. In the macroscopic approach, all variables are treated continuous functions of time and space. Velocity, pressure, and other variables are assumed as point functions. Thus, any theory of water transport to be useful must be developed to the point of describing the transfer of water on the macroscopic level. The coefficients of transport such as permeability and diffusivity can be defined microscopically. In many investigations which involve the transport of pesticides and fertilizes along with water , the simultaneous movement of water and solutes is of primary concern. These pollutants when mixed with water move in the unsaturated soil and finally join the region of saturated soil or water table, resulting in the contamination of fresh water existing below the water table. The scope of this report is to review the available literature, that may be categorized into two parts; one, the movement of water in unsaturated soil, and the other, the simultaneous movement of water and solutes in unsaturated soil. The papers, reviewed in this report, pertain to the theoretical study, laboratory study and field study on the two problems. At the end, an appendix appears which lists the references, categorizing the kind of study by various investigators.

Thesis (M.S.)--Rutgers University, 2008. / "Graduate Program in Civil and Environmental Engineering." Includes bibliographical references (p. 79-80).

A finite element groundwater flow model was used to support a hydrologic assessment for a study area in the Lower San Pedro River Basin which contains the Bingham Cienega. Consolidated sedimentary rocks associated with an extension of the Catalina Core Complex truncate the floodplain aquifer system in the study area. The elevated water table produced by this "hardrock" results in spring discharge at the cienega and a locally gaining reach of the San Pedro River. The steady -state model suggests that recharge (and discharge) components for the floodplain aquifer sum to 3.10 cfs. Mountain front recharge, underflow, and stream leakage are the primary recharge mechanisms, while stream leakage, evapotranspiration, spring flow, and underflow out are sources for groundwater discharge. A steady -oscillatory model was used to account for seasonal periodicity in the system's boundary conditions. Monthly variation in the evapotranspiration rate was offset primarily by storage changes in the aquifer. Due to a lack of measured hydrologic data within the study area, results from the model simulations are only preliminary. Model development and the subsequent sensitivity analyses have provided insight into what type of data needs to be collected. Head measurements are most needed in the area just downstream from Bingham Cienega. The mountain front recharge and evapotranspiration rates are shown to be highly sensitive parameters in the model; improved estimation of these values would be helpful. Spring discharge would be a valuable calibration tool if it could be accurately measured. A more extensive record of stream baseflow in the San Pedro River should be established. After more hydrologic data is collected, the model could be recalibrated so as to better represent the system. Eventually, this tool may be used in direct support of management and/or restoration decisions.

This report is in two parts. The first part covers the ecological processes pertinent to the restoration of Bingham Cienega. The second part presents a subregional groundwater flow model for analyzing the water budget, stream and spring behavior, and water table configuration. Because of the sparsity of ecological and hydrologic data, both parts must be considered as preliminary studies.

Dissertation (PhD)--Stellenbosch University, 1996. / One copy microfiche. / Some digitised pages may appear illegible due to the condition of the original microfiche. / ENGLISH ABSTRACT: The present network of now gauging stations in South Africa has grown from isolated observations on an ad extensive is to an extensive network of stations across the country. Standardised gauging stations to suit local conditions have been developed which include purposely desigll4:d compound weirs. Nearly all. compound gauging weirs In South Africa have. for practical reasons. been constructed without dividing walls. thus deviating lr',:.n the standards set by the British Standards Institution (1981). Uncertainty about the accuracy of calibration of such structures had to be darifi,ed and. where ~cessary. adjustments had to be made to existing calibration formulae in order to compensate for the de,,·iations. It was also necessary to determine whether the accuracies that could be attained were adequate in terms of the potential financial implications of inaccuracies. It has thus become necessary to re-evaluate the calibration of these structures which consist of mainly compound Crump .md sharp-crested weirs. Selected flow l"t'Cords were analysed and the data wa.\ used to determine the impact of errors on the required capacities of reservoirs. This wa., done in an anempt to provide guidelines for the accuracy required in flow records. An31ysing a single application of a flow record cannot provide guidelines for the required accuracy of a flow record and thus the gauging of flow. Although no general conclusions can be drawn. it appears thal the benefits arising from an improvement in the accuracy of a flow record are proportionally greater than the percentage improvement in accuracy. Three-dimensional flow conditions exist either upstream or downstream of the point of stage measurement depending on the presence or absence of diViding walls at a compound gauging weir. The existing calibro1tion theory does not account for the influences of three-dimensional flow conditions and a.-'isociatcd energy losses in the determination of the upstream total energy head. Hydraulic model tests were thus undenaken to detemline the magnitude of the resulting energy losses. New techniques were developed to compensate for these energy losses in the calibration theory of compound gauging weirs. Application of the new calculation techniques to rate compound weirs using a single point of stage measurement results in improvements in accuracy. It was found that compound weirs without dividing walls can be rated to greater levels of accuracy than weirs with dividing walls, where stage measurements are taken at a single point / AFRIKAANSE OPSOMMING: Die huidige nc!werk van vloclmectpumc III SUld-Afnka hel gegroei van gc'isoleerde waamemings op 'n ad hoc basis, tot 'n uitgebrcldc nctwerk. van meetpunte vcrsprei oor die hele land, Standaard mcetstruktuure aangepas vir plaaslike omstandighede is ontwikkei en sluit in doelgeboudc saamgestelde mcetstrukture. Byltans aile saamgestelde mcetstruklure in Suid-Afrika is weens praktisc oorwegings opgerig sonder verdeelmure, wal afwyk van die standaarde gestel deur die British Standards Institution (1981). Onsekerhede aangaande die akkuraathcid ,'an die kaJibrasie van sulke slrukture moes opgekJaar word en unpassjngs un die beSlaande leorie moes gedoen word om hier'OOf te kompenseer. iodien nodig. Oil was ook nodig om va~ Ie s,tel of akkuraathede Waf hulbaar is voldoende is, met inagneming Vlll poIensi~1c finamiitle implikasies van onakkuruthede. Oit hel dus nodig gcword om die bestaandc kaJibra.liic van saamgestelde meetstrukture. hoofsaakJik Crump en sterpkroin meetwaJle, Ie hcr·cval~r. Seleere vloei:rekords is ontl~ en die data is gcbruik om die impak van foule ~ bepaal op die berekende k.apasitei~ van opgaardamme. Oil IS gedoen in 'n poging om riglyne neer te Ie rakende die akkuraatheid verlang in 'n vloeirekord. Die ontleding van '0 enkele loepassing van 'n vloeirekord lewer nie genoegsame data om riglyne vas Ie stell. "ir die verlanp akkuraalheid van 'n vloeirekord of vloeimeling nie. AlhoeweJ geen duidelike riglyne hieruii vOilr1spruit nie. kom dit voor asof die voordele verkry uit '0 verbetering io die akkuraatheid van 'n vloeirekord in verhouding groter is as die vcrmiodering in die vloeimetingsfout. Drie-dimensionele II'loeitoeslande bestaan of stroomop of stroomaf van die punt van watervlakmeting, afl1iangende van die 'cenwoordigheid of afwesigheid van vcrdeelmure by 'n saamgestclde meetstlruktuur. Die beslaande kalibrasieleorie maak nie voorsiening vIr die invloed van drie-dimensionele vloeitoestande en die gepaardgaande energieverlicse op die bepahng van die totale stroomop energiehoogte nie. Hidrouliese mode1tor: sc is ondemeem om die omvang van die resulterende energieverliese vas te ste!. Nuwe tegnieke in die kaJibrasieteorie vir saamgestelde strukture is ontwikk.e1 0:t1 tc kompenseer vir hierdie energieverliese. 'n Verbc:tcde akkuraatheid word verkry wanneer die nuwe tegniek toegepas word op die kalibrasie van saamge~telde meetstrukture met 'n enkele punt van watervla.kmeting. Daar is gevind daR saamgestelde meetstrukture sonder verdeelmure illurater gekalibn:er lean word. as suuktt.Rmet vcrdeelmure waar walervlakke slegs by 'n enkclc punt gemeet word.

The budgeting of water fluxes in the soil is an extremely complex problem, and is compounded by subsurface controls and environmental forces which modify the soil water dynamics. Of the controlling factors, the underlying geology and the soil media are vital components and are often misinterpreted. The geology and soil media components have been neglected mostly because of the difficulty in monitoring the dominant processes that are linked to the water balance in the subsurface. Until recently, hydrometry has been the dominant method of measuring and monitoring the subsurface water balance. Hydrometric measurements have included water content measurement by Time Domain Reflectometry (TDR), soil water potential measurements through tensiometry and groundwater water level monitoring. Hydrometry is still the preferred method of monitoring soil water dynamics, but measurements are generally localised and lateral accumulations and fluxes of water are difficult to interpret. Using geophysical methods and instrumentation to define soil water dynamics could have numerous advantages over conventional hydrometric methods. Among the geophysical techniques dedicated to image the near surface, Electrical Resistivity Tomography (ERT) surveying has been increasingly used for environmental, engineering and geological purposes during the last decade. The aim of this study is to determine if ERT observations could yield the accuracy required to define vertical and lateral soil water dynamics. The ERT instrumentation uses an electrical current that is inserted into the subsurface through various electrode arrangements and a resulting resistance is determined at the take-out electrodes. With the aid of a modelling package these resistance values are reproduced into a pseudosection of underlying resistivity distribution which is influenced by the moisture conditions of the subsurface medium. This geophysical method is primarily used for geological studies but by doing repeated surveys with the same electrode positioning, moisture fluctuation monitoring could be realised. Use of the ERT technique is at the forefront of soil water dynamics monitoring. The main objective of this study is to propose that the ERT instrumentation could be a more efficient and more informative method of studying soil water dynamics than the traditional soil water dynamics monitoring equipment, particularly to define lateral fluxes and accumulation of subsurface water. The study site is a well instrumented transect in the Nkuhlu Exclosures in the Kruger National Park, South Africa, where ongoing soil water dynamics are monitored. The project aims to compare the ERT data to fiR data on a daily basis, over a period of three weeks, during the rain season, monitoring event based wetting and the subsequent drying phases of the soils in a 2-dimensional section. The project and its fmdings are shown to be valuable to the hydrological interpretation of the subsurface water balance. The application is shown to be particularly important to ecohydrology, in the monitoring of soil water dynamics in a 2-dimensional transect and understanding how the natural cycles of water distribution and plant uptake are linked together. The study demonstrates that ERT can be used to observe changes in the water storage and lateral fluxes within a transect which supports varying vegetation and ecologies. The linking of water fluxes in the hydrology cycle to uptakes and controls in the ecosystem has been developed into the research focus known as ecohydrology The use of the ERT instrument can only benefit this research focus in the future. The study demonstrates that ERT instrumentation can be used to provide valuable understanding of subsurface water dynamics and in turn the effects on ecohydrology. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2006.

[Truncated abstract] Centrifugal pumps are the most prevalent, electrically powered rotating machines used today. Each pump is designed to deliver fluid of a given flow rate at a certain pressure. The point at which electrical energy is converted most efficiently into increased pressure is known as the Best Efficiency Point. For a variety of reasons, pumps often operate away from this point (intentionally or otherwise), which not only reduces efficiency, but also increases the likelihood of premature component failure. Acoustic emissions (AE) are high frequency elastic waves, in the range of 20-2000kHz, released when a material undergoes localised plastic deformation. Acoustic emission testing is the process of measuring and analysing these stress waves in an attempt to diagnose the nature and severity of the underlying fault. AE sensors mounted on the surface of a machine or structure also detect any stress waves generated within the fluid being transmitted through to the structure. Unfortunately, attempts to detect incipient component faults in centrifugal pumps using acoustic emission analysis have been complicated by the sensitivity of AE to a pump?s operating state. Therefore, the aim of this thesis was to determine how acoustic emission monitoring could be used to identify the hydraulic conditions within a pump. Data was collected during performance tests from a variety of small end-suction pumps and from one much larger double-suction pump. A system was developed to collect, process and analyse any number of AE features (be they related to discrete AE events, or due to the continuous background AE level) from continuously operating equipment. ... Unfortunately, results from smaller pumps were less conclusive, particularly at low flows, probably due to the relatively small changes in hydraulic energy across the range of flows, and consequent sensitivity to the testing process. However, even in these pumps consistent patterns in hit energies were observed resulting in the conclusion that low to medium flows in centrifugal pumps are typified by a very large number of very low energy (VLE) events. These decrease in number and increase in energy as flow approaches BEP and/or is reduced to very low flows. High flows above BEP are marked by an absence of these VLE events, with bursts having significantly higher energies and spread over a much greater range. Unfortunately, these VLE events are too small to affect averaged trends, indicating that further work on a suitable filter is required. vi