In two-dimensional flow, the point of flow separation from the surface coincides with the point at which the skin friction vanishes. However, in three-dimensional flow, the situation is much more complex and the flow separation is rarely associated with the vanishing of the wall shear stress except in a few special cases. Though the effects of cross-plane separation are substantial and have been recognized for some time, the phenomenon of flow separation over three-dimensional bodies is still far from being completely understood. The flow is so complex that no completely satisfactory analytical tools are available at the moment. In an attempt to logically identify the various effects and parametric dependence while simultaneously minimizing configuration dependent issue, the flow over a 6 to 1 prolate spheroid, which is a generic three-dimensional body, is investigated. For the identification of the general flow pattern and better understanding of the flow field, surface-oil-flow visualization tests and force and moment tests were performed. The angle of attack effect and Reynolds number effect on the separation location are studied with natural transition. Forces and moments tests, surface pressure distribution measurements as well as the surface pressure fluctuations, and mini-tuft flow visualization tests were made to document the flow characteristics on the surface of the body with an artificial boundary layer trip. / Ph. D.

Surrogate organisms have been used to study highly pathogenic organisms, or organisms that cannot be cultured in the laboratory. Surrogates are selected based on multiple similarities to the pathogen, such as morphology, genome size and structure, and environmental characteristics. This dissertation utilized MS2 coliphage as a surrogate for norovirus and Ebola virus in three environments. MS2 is an icosahedral, single-stranded RNA bacteriophage. It is a male-specific coliphage that infects the bacteria Escherichia coli. Its properties, such as morphology and survival in the environment, have been likened to those of many enteric viruses. Because of this, it has been used as a surrogate for pathogenic enteric viruses for disinfection testing on surfaces, in water and in food; modeling the movement and survival of pathogens in different environments; and transfer properties from surfaces. This dissertation utilized MS2 as a surrogate in three different studies. In the first, MS2 is used as a surrogate for human enteric viruses in irrigation canals to predict the re-suspension of pathogenic viruses from bed sediment into overlying irrigation water using a flume to re-create field conditions in the laboratory. MS2 re-suspension into the overlying water was characterized at varying flow rates and velocities using two sediment types. Its overall re-suspension was not statistically significantly different (p > 0.05) between flow rates. The additional studies in this dissertation used MS2 as a surrogate for Ebola virus in human waste. Ebola virus is a BSL-4 organism that is spread through direct contact with bodily fluids. It is found in bodily fluids in concentrations between 10^5.5 and 10⁸ genome copies per milliliter. In the first study using MS2 as a surrogate for Ebola virus, efficacies of four disinfectants were tested using 10¹² PFU of MS2 in one liter containing 2.25% (w/v) organic matter at three contact times (1, 15 and 30 minutes). The purpose of this study was to assess the disinfectants on reducing virus in waste before toilet flushing. Peracetic acid and quaternary ammonium formulation were found to reduce the concentration of MS2 in the toilet bowl the fastest (within one minute) with the greatest reduction (2.26 and 1.99 log₁₀), when compared with the other disinfectants. Reductions observed from hydrogen peroxide were significantly less than those from peracetic acid and quaternary ammonium (p < 0.05). The contamination of restroom surfaces by MS2 was also evaluated after toilet flushing with and without disinfectant treatment. All four disinfectants were found to significantly reduce the viral concentrations on fomites after 15 minutes of contact (p < 0.05). Despite disinfectant use, three sites were contaminated in 100% of trials (N = 18). These were the toilet bowl rim, the toilet seat top and underside. The final study evaluated the inactivation of MS2 and several other viruses by thermophilic and mesophilic anaerobic digestion. Little information is available on the influence of the wastewater treatment process, specifically anaerobic digestion, on emerging viruses, such as Ebola virus. It is important to evaluate this process due to the environmental disposal and discharge of wastewater and solids into the environment. All viruses were recoverable after mesophilic digestion (reductions from 1.8-6.6 log₁₀ per mL), except the lipid-containing bacteriophage Φ6. Thermophilic digestion inactivated all viruses significantly (p = 0.0011) more than mesophilic digestion. The reductions by thermophilic digestion ranged from 2.8-7.1 log₁₀ per mL. The inactivation between the initial concentration and both digestion types was statistically significant (p = 0.007).

Advances in mathematical modelling and the availability of high speed computers with considerable memory size is making it possible to study the hydraulics of border irrigation in a greater depth than every before. A zero inertia mathematical model was found to be reliable and inexpensive among the models available in border irrigation hydraulics and was used for this study to simulate free outflow flowing border irrigation. Special emphasis was given to the runoff produced from such a system. This study dealt particularly with, the identification of pertinent open channel variables affecting runoff in border irrigation, presentation of predictive graphical and mathematical solution to quantify runoff, and with utilization of these solutions in developing reuse system design criteria. Inflow rate, surface resistance, border slope, soil infiltration characteristics, application time (time of cutoff and length of run of the border) were among other variables studied. As one might expect, runoff was found to increase with slope, flow rate, application time and decrease with increase in infiltration rate, length of run and bed and vegetation drag. Considering the number of variables affecting runoff characteristics from a given irrigation, it was obvious to see a thorough examination of each variable in dimensional terms was practically impossible. Also, presentation of the results would have required too many graphs. Dimensional anslysis was used to solve this problem and in developing dimensionless runoff curves. The ability to quantify runoff made it possible to develop reuse system design formula for proper sizing of reuse systems under several operational requirements. Shape function for the ultimate infiltrated depth profile was used to get times of runoff and also calculate various efficiencies which are useful for evaluating the system. The study shows, through the use of reuse system, the potential application efficiency can be changed from present values of 60 percent to 90 percent in Arizona. It also can be used to demonstrate the saving in energy that can be realized through such system. Step by step procedures for the design of reuse system using graphical and mathematical solutions are presented with a sample problem worked out. It is expected that the result of this study can be used by designers as well as operators of border irrigation systems without any difficulty with the aid of a simple pocket calculator. Other uses of the study include getting optimal design for the system itself by evaluating various possible designs and classroom instruction on the application of dimensional analysis to open channel hydraulics problems and design of reuse systems.

The Central Arizona Project (CAP) is a billion-dollar-plus project to construct an aqueduct to transport water from Lake Havasu on the Colorado River into the Maricopa County-Phoenix area and then through Pinal County to Tucson. Upon completion of CAP in 1986, some of the Colorado River water will be delivered to Pinal County for agricultural use. Water available to Pinal County farmers in the initial years of the project is estimated at 659,000 acre-feet annually. Any new importation of water to an established irrigated agricultural area implies adjustments in the organization of the economy of the area. For irrigated agriculture, adjustments will occur in input mix, output mix, acreage farmed, and in gross and net incomes. A complicating factor associated with importation of Colorado River water is that the imported water will contain different dissolvedsalt concentrations than will the groundwater and surface water currently being used. Dissolved salts in irrigation water (salinity) decrease crop yields, i.e., as the salinity of water applied to a crop increases, yield per acre decreases. The magnitude of yield reduction due to salinity is dependent on the level of salinity of the irrigation water and on the crop's salt sensitivity. In areas of Pinal County where local water supplies have a lower average salinity than CAP water, average crop yields will decrease if CAP water is added to the crop-water mix. On the other hand, in those areas where the salinity of local water is higher than that of CAP water, higher crop yields will be realized by using CAP water in the crop-water mix. Thus, the optimal CAP-local water mix is determined in order to evaluate the economic adjustments of Pinal County farmers to the new water source. Pinal County is divided into seven irrigation districts, each of which has filed a letter of intent to purchase CAP water. Representative farm data for each district are stratified by farm size and pumping depth. Farms are divided into four size classes in order to reflect economies due to farm size. Because the cost of local pumped water varies with the pumping lift, the farms are also stratified by three depth-to-water classes. Thus, a total of 12 representative farms are necessary to describe the agricultural activities in each irrigation district, and 84 representative farms are needed for the county. Mathematical programming models of representative irrigated farms in Final County project adjustments implied under several assumptions as to the availability, cost and salinity of irrigation water from various sources. Results show that (1) most monetary benefits of the project will be captured by the Indian farmers of the county, (2) groundwater conservation will be minimal unless farmers are forced to purchase large quantities of CAP water, (3) provision of CAP water will not affect cotton acreage but will significantly increase the acreage of small grains and alfalfa, (4) the possibility of increased salinity from CAP water should not concern farmers in the county since projected decreases in net income occurring because of increased salinity average only 61 cents per acre per year, and (5) increased income to non-Indian farmers resulting from provision of CAP water at the currently proposed price will not be sufficient to pay the additional fixed costs for distribution systems.

Thesis (MSc Food Sc)--Stellenbosch University, 2011. / ENGLISH ABSTRACT: The increased consumption of fresh produce has been shown to be related to increases in foodborne disease outbreaks and these have in many cases been ascribed directly to carry-over of pathogens from contaminated irrigation water. In South Africa, rivers are the main source of irrigation water but many have been found to be unsuitable for irrigation of fresh produce because of the unacceptably high levels of faecal contamination. The main aim of this study was to do a baseline evaluation of the microbiological quality of the Plankenburg and Eerste Rivers and to determine which bacterial contaminants are present. Two sampling sites were selected for the Plankenburg (Plank-1 and -3) and one for the Eerste River (Eerste-1). The microbiological analysis included aerobic colony count (ACC), aerobic and anaerobic sporeformers, Staphylococcus, Salmonella, Listeria, enterococci, coliforms, faecal coliforms and E. coli using standard methods. The faecal contamination levels for both rivers exceeded the DWAF and WHO guidelines of <1 000 E. coli per 100 mL water for irrigation of fresh produce intended to be consumed raw. The Plankenburg River sites always had higher coliform contamination levels (1 200 - 13 000 000 MPN per 100 mL water) than the Eerste River site (230 - 79 000 MPN per 100 mL water). There was also a high incidence of index organisms including Salmonella, Staphylococcus, Listeria and endosporeformers. The isolation of intestinal enterococci suggested the presence of potential pathogens that can cause disease outbreaks. The baseline data also showed large variations in microbial loads over the 15 month study with the faecal coliform counts ranging for Plank-1 from 1 200 to 7 000 000 MPN.100mL-1, Plank-3 from 10 to 460 000 MPN.100mL-1 and Eerste-1 from 28 to 79 000 MPN.100mL-1. The water temperatures at all three sites ranged from 12.1° to 21.7°C with COD values in most cases below 100 mg.L-1. As the baseline study showed large variations in microbial loads over the 15 month study period an assessment using the Colilert-18 system of the weekly, daily and hourly variations, for 6 weeks over a period of 4 months was conducted at site Plank-2. This site was specifically used as it is an irrigation source point for nearby fresh produce farmers and is about 2 km further downstream from an informal settlement. The weekly variation trend for total coliforms (TC) showed a decrease over the entire sampling period with the highest count of 3 200 000 MPN.100 mL-1 during the warmer period. The E.coli (Ec) counts showed a similar trend with the highest count of 440 000 MPN.100 mL-1 also in March. The daily variation trends were the same for both the TC and Ec and counts found to increase from Monday to Thursday followed by a decrease to Sunday. The highest counts were on Thursday with average TC and Ec counts of 1 900 000 and 160 000 MPN.100 mL-1, respectively. The hourly variation trends were similar for both TC and Ec with counts increasing from 06h00 to 12h00 followed by a decrease to 18h00. The increases in TC and Ec counts found during the weekly, daily and hourly variation trend studies clearly suggests that the 15 month sampling that was done once a month on Mondays at 08h00 could be considered an underestimation of the contamination levels of the Plankenburg and Eerste Rivers. The overall weekly variation trend for the water temperature showed a decrease over the sampling period while the daily and hourly variation trends showed an increase from 06h00 to 18h00. The overall weekly trend for pH differed from that of the temperature with an increase over the sampling period. The analysis of covariance showed no correlation (p < 0.05) between the physico-chemical (temperature and pH) and the microbial variables (TC and Ec). Therefore it was concluded that temperature and pH had no direct impact on either the total coliform or E. coli counts. Both the Plankenburg and Eerste Rivers were found to be unsuitable for the irrigation of fresh produce intended to be consumed raw due to the high levels of faecal contamination that exceeded DWAF and WHO guidelines. Irrigation with such water could pose a health risk because of presence of potential pathogens that could be carried-over to fresh produce. / AFRIKAANSE OPSOMMING: Die toenemende gebruik van vars produkte hou direk verband met die toename in voedseloordraagbare siektes. Alte dikwels kan dit toegeskryf word aan die teenwoordigheid van patogene in besproeiingswater. In Suid Afrika is riviere die hoofbron van besproeiingswater maar dit is al gevind dat meeste ongeskik is vir gebruik as besproeïngsbron as gevolg van die onaanvaarbare hoe vlakke van fekale besmetting. Die hoofdoel van hierdie studie was om ‘n basislyn evaluasie van die mikrobiologiese kwaliteit van die Plankenburg en Eerste Riviere te doen en ook vas te stel watter bakteriese kontaminante teenwoordig is. Twee bemonsteringpunte is geselekteer vir die Plankenburg (Plank- 1 en -3) en een vir die Eerste Rivier (Eerste-1). Mikrobiologiese analises met standaard metodes het die volgende ingesluit: aërobe kolonie telings (AKT), aërobe en anaërobe spoorevormers, Staphylococcus, Salmonella, Listeria, enterococci, koliforms, fekale koliforms en E. coli met gebruik van standaard metode. Die fekale besmettingsvlakke vir beide riviere het die DWAF en WHO leistreep van <1 000 E. coli per 100 mL water vir besproeiing van vars produkte wat rou geëet kan word oorskry. Die Plankenburg Rivier bemonsteringspunte het in alle gevalle ‘n hoër kolivorm besmettingsvlak (1 200 - 13 000 000 MPN per 100 mL water) as die Eerste Rivier punt (230 - 79 000 MPN per 100 mL water) gehad. Daar was ook ‘n hoër voorkoms van indeksorganismes insluitend Salmonella, Staphylococcus, Listeria en endosporevormers. Die voorkoms van ingewand enterococci was ‘n addisionele aanduiding van die voorkoms van patogene wat ernstige gesondheidsrisikos vir die verbruiker kan inhou. Die basislyn data het groot variasies in die mikrobe vlakke oor die 15 maand van studie getoon. Die faecal koliforms vir Plank- 1 het gewissel van 1 200 tot 7 000 000 MPN.100mL-1, vir Plank-3 van 10 tot 460 000 MPN.100mL-1 en vir Eerste-1 van 28 tot 79 000 MPN.100mL-1. Die water temperature het gewissel van 12.1° tot 21.7°C met die CSB waardes in meeste gevalle minder as 100 mg.L-1. Aangesien daar sulke groot variasies in mikrobe ladings oor die 15 maande tydperk voorgekom het, is die Colilert-18 sisteem gebruik om die weeklikse, daaglikse en uurlikse variasies vas te stel vir 6 weke oor ‘n periode van 4 maande by die Plank-2 bemonsteringspunt. Daar is spesifiek op die bemonsteringspunt gefokus omdat dit as ‘n besproeiingsbron gebruik word deur groente produsente. Dit is ook gelee ongeveer 2 km stroomaf van ‘n informele nedersetting. Die weeklikse variasies in totaal koliforms (TC) het ‘n afname oor die hele bemonsteringsperiode getoon, met die hoogstes telling van 3 200 000 MPN.100 mL-1 gedurende die warmer tydperk. Die E.coli (Ec) tellings het ‘n soortgelyke neiging getoon, met die hoogste telling van 440 000 MPN.100 mL-1 ook in Maart. Die daaglikse neigings was dieselfde vir beide die TC en Ec en die tellings het vermeerder van Maandag tot Donderdag, met ‘n afname tot Sondag. Die hoogste telling was op Donderdag met gemiddelde TC and Ec tellings van 1 900 000 and 160 000 MPN.100 mL-1, respektiewelik. Die uurlikse variasie profiel was soortgelyk vir beide TC and Ec met tellings wat vermeerder het van 06h00 tot 12h00 gevolg deur ‘n afname tot 18h00. Die toename in TC en Ec getalle soos vasgestel gedurende die weeklikse, daaglikse en uurlikse variasie het duidelik getoon dat die bemonsterings wat een maal per maand op Maandae om 08h00 gedurende die 15 maande tydperk uitgevoer is, tot ‘n erg onderskatting van die besmettings vlakke in die Plankenburg en Eerste Riviere gelei het. Die algehele weeklikse variasies vir die water temperatuur het ‘n verlaging oor die bemonsteringstydperk getoon terwyl die daaglikse en uurlikse variasie neigings ‘n verhoging van 06h00 tot 18h00 getoon het. Die weeklikse neigings vir pH het van die van die temperatuur verskil. Die analises van kovariante het geen korrelasie (p < 0.05) tussen die fisiese-chemiese (temperature en pH) parameters en die mikrobe veranderlikes (TC en Ec) getoon nie. Dus is daar afgelei dat temperatuur en pH geen direkte impak op die totale kolivorm of E. coli tellings gehad nie. Die data van die studie het duidelik getoon dat water van beide die Plankenburg en Eerste Riviere nie geskik is vir gebruik vir besproeiing van vars produkte wat rou geëet gaan word nie. In beide gevalle het die fekale besmettingsvlakke die DWAF en WHO leistreep oorskry. Besproeiing met sulke water hou ‘n gesondheidsgevaar in as gevolg van die teenwoordigheid van potensiële patogene wat oorgedra kan word na vars produkte.

Thesis (MTech (Agriculture))--Cape Peninsula University of Technology. / During the past years government regulations concerning winery effluent became stricter to protect the environment. Wineries are continually improving wastewater management and finding appropriate ways to reduce cellar effluent. Due to water scarcity in South Africa, it could be a huge advantage if winery effluent could be used as irrigation water for vineyards. If the industry can re-use the untreated wastewater, it will not only save a huge amount of irrigation water, but it will also be able to get rid of the vast amount of cellar effluent. Grape production plays a major role in agriculture worldwide. The world production of grapes worldwide in 2013 was 751 MgL. South Africa is the 9th biggest wine producer in the world with 10 X 10HL of wine. In the earlier years of wine production in South Africa, the small volumes of winery wastewater did not have a negative impact on the environment but with the increased volumes over the last years, the possibility of contamination of the soil and the environment has increased. Government decided to regulate the irrigation of cellar effluent with the National Water Act of 1998 as approved by the Department of Water Affairs (DWAF). There are different ways to get rid of cellar effluent. One successful way is by constructed wetlands where plants are used to break down minerals which could be detrimental to the environment. This is a successful way to get rid of cellar effluent but could take up to six weeks before the mineral contents can be broken down by the plants. Another way is to use bio-reactors to break down the contents of the cellar effluent, but this is expensive. Wastewater consists of important nutrients needed for plant growth such as macro-nutrients like N, P, K and micro-nutrients like Fe, Zn, Mn and Cu and a substantial amount of organic matter. If cellar water, just like domestic wastewater is used for irrigation the farmer can save water when he uses less fertiliser, because of the high nutrient content in the cellar effluent. If cover crops such as oats (Avena sativa L. cv. Pallinup) in winter and pearl millet (Pennisetum glaucum (L.) R. Br.) in summer can be used to remove excess cations, as well as unwanted chemicals such as toxic metals from the soil, it may result in effluent water with a higher chemical oxygen demand (COD) level than the current legal limitations that can be used to irrigate the vineyard. The aim of this project was, therefore, to determine the ability of oat and pearl millet cover crop to remove excess minerals from the soil irrigated with augmented water at different COD levels, without a negative effect on growth and yield of the vineyard or wine quality. Field trials were carried out in a Cabernet Sauvignon/99 Richter vineyard established on a sandy soil at the Goudini Cellar near Rawsonville.

O meloeiro rendilhado (Cucumis melo L. var reticulatus Naud.), por apresentar alto valor comercial, tem sido uma opção de plantio para os produtores de hortaliças. Com o objetivo de avaliar as extrações de nutrientes desse meloeiro cultivado em ambiente protegido, em função de doses de potássio e da utilização de dióxido de carbono (CO2) na água de irrigação, (água carbonatada), realizou-se este trabalho no período de setembro a dezembro de 2001 no Departamento de Engenharia Rural da USP/ESALQ, em Piracicaba, Brasil, à latitude de 22º 42’ 30" S, longitude de 47º 30’ 00" W e altitude de 580m. Para isso, foram utilizadas duas estufas, nas quais foram aplicadas quatro doses de potássio (50, 150, 300 e 600 kg ha -1 de K2O) via sistema de irrigação por gotejamento. Em uma das estufas foi aplicado 301,8 kg ha -1 de CO2 via água de irrigação, porém de forma separada da aplicação de potássio. A outra estufa foi mantida no nível atmosférico de CO2 (condição natural). O delineamento experimental utilizado foi blocos casualizados com quatro repetições. Para obtenção da extração dos nutrientes ao longo dos estádios fenológicos, as plantas foram coletadas no dia do transplantio (muda), no desenvolvimento vegetativo, no início do florescimento, no início e meio da frutificação e no período de colheita. Verificou-se que a dose de 300 kg ha -1 de K2O foi a que proporcionou maior produção de frutos, maior peso médio e comprimento médio dos frutos. A aplicação de CO2 via água de irrigação proporcionou aumento da ordem de 11% na produção total de frutos, 20% na produção comercial e 23% no número de frutos comerciais. A extração de nutrientes acumulados na parte aérea teve maior incremento entre o início do florescimento e o início da frutificação, independente dos tratamentos. A ordem de extração dos macronutrientes acumulados na parte aérea foi: potássio > nitrogênio > cálcio > magnésio > enxofre > fósforo. A aplicação de CO2 aumentou a extração de zinco, e diminuiu a extração de potássio e magnésio. Para os micronutrientes, a ordem da extração acumulada na parte aérea em ambos os sistemas utilizados foi: ferro > manganês > zinco > cobre ~ boro. As doses de potássio aumentaram a extração desse nutriente acumulado na parte aérea da planta na colheita, e não influenciaram os demais nutrientes. / For presenting more commercial value, the net melon (Cucumis melo L. var reticulatus Naud.) has been an option of greenhouse planting for the horticulturists. Aiming to evaluate the nutrients extractions from this melon cultivated in greenhouse in function of potassium rates and by the use of carbon dioxide (CO2) in the water irrigation (carbonated water), this work was carried out from September to December 2001, in the experimental area at Agricultural Engineering Department of USP/ESALQ in Piracicaba, Brazil at 22º 42’ 30" S latitude and 47º 30’ 00’ W longitude and 580m of altitude. Two greenhouses were then used in which were apllied four rates of potassium (50, 150, 300 and 600 kg ha -1 of K2O) via drip irrigation system. In one of the greenhouse was apllied 301.8 kg ha -1 of CO2 injected through water irrigation in a separate way from de potassium injection. The other greenhouse was kept in the atmospheric level of CO2 (natural condition). The experiment was conducted in fully randomized blocks, with four replications. To obtain the nutrients extraction through the stages of plant development, the plants were collected in the transplant day (seedling), in the vegetative stage, in the beginning of the flowering stage, in the beginning and in the middle of fruit production and in the harvest period. It was verified that the rate of 300 kg ha -1 of K2O was better to fruits production, to the medium weight and medium height of the fruits. The CO2 injection in the water irrigation increased 11% the total yield 20% of commercial yield and 23% the number of commercial fruits. The greatest increase of nutrient extraction happened between the beginning of the flowering and the beginning of the fruit production being independent of the treatments. The order of macronutrients accumulated in aerial part was: potassium > nitrogen > calcium > magnesium > sulphur > phosphorus. The CO2 injection in the water irrigation increased the zinc extraction and reduced the potassium and magnesium extraction. For the micronutrients in both used systems the order of extraction obtained was: iron > manganese > zinc > copper ~ boron. The potassium rates increased the extraction on this nutrient accumulated in the aerial part of the plant in the harvest and did not influence the other nutrients.

Water provides the lifeblood of Utah's agricultural economy. It Is the subject of much controversy and litigation and yet most opinions on the subject are based on opinions and prejudice rather than upon the basis of sound scientific examination. This paper attempts to provide some of the economic information necessary for sound decisions in the development and use of Utah's water resources with respect to agriculture. Utah has been divided into ten drainage regions (hydrologic subregions) and the presently irrigated and potentially irrigable land according to land class was estimated for each county or portion of a county within each of the regions. Water use factors, crop rotation constraints, costs of production, yields, product prices, and costs of bringing new land into production were also estimated. These values were then used in the linear program demand model to estimate a normalized demand (marginal value product) curve for water to be used in agricultural production within each region. The available level of water was varied in each of the demand curves to estimate the relationship between the quantity of water and its economic value (a demand function).

Thesis (M.S.)--Oregon State University, 2007. / Printout. Includes bibliographical references (leaves 198-204). Also available on the World Wide Web.

<p>This research investigated the nature, source and the spatial variation of the salinity of the water used for irrigation in the urban farming area of Philippi, which lies in the Cape Flats region of the Cape Town Metropolitan Area, South Africa. The irrigation water is mainly drawn from the Cape Flats aquifer, and pumped into ponds for eventual crop irrigation. Water samples were collected in summer and in winter from fifteen selected sites using standard water sampling procedures. Each site consisted of one borehole and one pond. The samples were routinely analyzed for salinity levels, and concentrations of major and minor ions. From the same boreholes and ponds, water was sampled in summer for isotope analysis to assess effects of evaporation on the water quality and salinity. Descriptive statistics were used to display the variation in range of specific ions in order to compare them with the recommended ranges. Geographical Information Systems analysis described the spatial distribution of the salinity across the study area, and hydrogeochemical analysis characterized the various waters and detected similarities between the water samples in the study area and other waters found in the Cape Flats region. In addition, the US salinity diagram classification of irrigation water developed by Richards (1954) was used to assess the current suitability of groundwater and pond water samples collected during the entire sampling period for irrigation activities. The research indicated that the concentrations of some ions such as chloride, nitrate, potassium and sodium exceeded in places in the study area, the target range values set by the Department of Water Affairs and Forestry (DWAF, 1996) and the Food and Agriculture Organization (Ayers and Westcot, 1985). It revealed that borehole and pond water were mostly brackish across the area regarding their total dissolved salts content, and fresh water was only found in the middle part of the study area. The research found that sea water does not intrude into the aquifer of the study area, and the accumulation of salts in groundwater and soil in the study area is mainly due to the agricultural activities and partially due to the natural movement of water through the geological formation of the Cape Flats region. The conceptual model of the occurrence of the salinization process supported these findings. From this investigation it is understood that the groundwater and pond water in the study area were generally suitable for irrigation purposes but they have to be used with caution as the vegetables are classified as sensitive and moderately sensitive to salt according to DWAF Irrigation water guidelines (1996). The quality of these waters was mainly affected by the land use activities.</p>