The research was undertaken to simulate the surface transport of water and chemicals from a flat agricultural watershed at the Green Belt farm in Ottawa, Ontario, Canada. The GIS database created for the Black Rapid Creek watershed focused on attributes and data necessary to run a non-point source model for surface transport of water and chemicals called AGNPS. The GIS used in the current study was SPANS for the OS/2 warp (version 3) environment. The years of simulation for the study area were 1992 and 1993. The study was carried out on a watershed scale and flow routing from different cells to the outlet of the watershed was simulated with AGNPS under different management practices. The results of the study indicate that input variables of AGNPS model for a flat agricultural watershed, flow direction, precipitation event and topography of the land, affect the surface runoff volume at the outlet considerably. (Abstract shortened by UMI.)

Non point source pollution (NPS) has long been the negated form of pollution within our natural systems. With an increase in the demand for quality crops and staple foods, there have been added pressures on water systems to cope with increasing NPS pollution (NPS-P). The effect and importance of scale on the assessment of NPS pollution has been identified as a pivotal component in the assessment of such pollutants, in particular the translation of processes from a field to a catchment scale. It has therefore become important to further investigate and research the processes involved in transporting and retaining pollutants at each measurement scale. A number of models have been developed for simulation catchments, however none of the suitably address the issue of NPS pollution and the translation of processes from the field through to the catchment scale. Each model researched fails to effectively address processes over varying scales, and tend to concentrate on a particular scale of observation. There is a distinct lack of a capable mechanism that assesses NPS pollution across varying scales within a catchment. The Water Research Commission (WRC) NPS-P project aims at eventually developing a successful model that addresses the issue of assessing NPS pollution across a number of different scales. This study aimed at assessing the loads of sediments and nutrients at different scales and included the establishment of a research catchment in the Mkabela Catchment outside Wartburg in KwaZulu-Natal, and the collection and interpretation of rainfall, runoff and nitrate data for a full year of sampling. The sampling provided valuable data for the calculation of pollutant masses and concentrations within the Mkabela Catchment. Non Point Sources are generally more dilute with suspended solids and nitrate in particular tending to have a high transport dependence upon summer events with a high intensity and low duration. A varying degree of scales were monitored during this study, ranging from plot to catchment scale in order to assess the varying influences on NPS Pollution (Nitrate and Suspended Solids). Monitoring was conducted through research mechanisms ranging from runoff plots at the plot scale to catchment scale flumes. It was found that scale has a varying influence on NPS pollution, with pollutant concentrations measured to be at a maximum at the field scale, with a value of 13.54mg/l of nitrate measured within the cane fields from event 3. Suspended solid values taken from within the water samples were most apparent at the plot scale, within the runoff plots, with a maximum of 2866.7mg/l measured during event 3 as well. It was evident from measurements and results obtained for each of the 10 sampled events that the main influencing factor of the nitrate concentrations and suspended solid values was the nature of the event. Summer rainfall events (high intensity and short duration) provided large overland flow volume that contributed largely towards the high concentrations of both nitrate and suspended solids, whereas the winter rainfall event (low intensity and long duration) contributed little to the concentrations of nitrate and suspended solids. In contrast to nitrate concentration, the largest nitrate loads by mass were measured during event 1 at the large catchment scale (Bridge 2), with a total cumulative load of 74.17kg nitrate estimated to have been yielded at the catchment outlet. The majority of nitrate are yielded from the agricultural lands where farming practices lead to the application of chemicals preplanting and post emergence. Suspended solids displayed a similar trend to that of nitrate, with an increasing cumulative yield measured throughout the catchment, resulting in a total 13414kg of sediment being measured at Bridge 2. It is interesting that Event 1 measured the largest cumulative loads for both nitrate and suspended solids; however it was recorded as an average intensity event (19.1mm/h) in comparison to the largest sampled intensity event of 165.9mm/h (Event 4) during the study. This may be attributed to the fact that the event coincided with the planting schedule of the sugarcane crops, and so the bare nature of the agricultural fields resulted in increased overland flow, and hence nitrate and suspended solid transportation. Data collected during all the events clearly show that the impoundment (a farm dam) acts as a water quality filter by retaining many of the nitrate pollutants when they enter the dam as channel flow. In summary, the controlling processes governing NPS-P movement varied through the differing scales, with crop size, artificial chemical application, nature of the event and timing during the year all contributing in varying manners at the differing scales. Future research within the WRC-NPS-P project should continue with sampling from the designated research points and add several more seasons of data to the already comprehensive first season of sampling. In addition, once a reasonable number of seasons have been sampled and analysed within the Mkabela Catchment, the initiation and development of an effective, representative scaled NPS-P model that addresses the movement and retardation of pollutants is necessary to be able to successfully model and predict the movement of NPS-P through catchment systems. In particular the effects of the controls afforded by such features as road crossings, wetlands and farm dams should be taken into account in the modelling of sediment and nutrient movement from field to catchment scale. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2011.

The objective of this study was to apply the WEND model, a nutrient mass balance model, to the Castor watershed in southern Quebec to evaluate phosphorus movement, storage and export over time. The WEND model was customized to run on a field-scale and then individually applied to 266 fields on the watershed for a 30-year simulation period. Field-specific information for the period of 1997-1999, was used as basic inputs to the model. Climatic information was obtained from local sources. The additional information required to run the model was derived from the literature. Model outputs were analysed at three different levels: (i) the overall watershed impacts, (ii) by cropping system, and (iii) for field management practices presenting a high risk of P losses. Specific outputs examined were: soil test Mehlich-III P, soil P saturation with aluminium, RUSLE soil loss potential and TP export. / The model was used to examine the impacts of crop rotations, fertilizer application and tillage management on TP export. For the Castor watershed, the soil test P increased at a mean rate of 3.71 kg Mehlich-III P ha -1 yr-1, equivalent to a mean input of about 32 kg P2O5 ha-1 yr-1 in excess of plant requirements, assuming current field management practices remain constant. / If TP export is considered the most important parameter in terms of P contamination, crop rotations are a good alternative to continuous corn monocropping under which losses could reach as high as 3.36 kg TP ha-1 yr -1. Crop rotations were shown to be an important management practice that should be more carefully examined when establishing field management practices. Just one year of grassland within a rotation can greatly improve the overall environmental health of a watershed. The management of P inputs is also an important target for improvement, as fertiliser inputs often surpassed plant requirements by two- or three-fold.

Em caráter experimental, a tese examina o desempenho de sistemas de biorretenção na mitigação da poluição difusa ocasionada pelas águas de chuva. A avaliação dessa tecnologia ambiental urbana partiu da construção de um modelo de manejo dos escoamentos pluviais, utilizando uma matriz orgânica composta por vegetação, solo e agregados para retenção e tratamento inicial localizados. O protótipo, em escala 1:1, implementado na Cidade Universitária Armando Salles de Oliveira (CUASO-USP), São Paulo, SP, é composto por dois canteiros isolados entre si, que recebem as vazões através da sarjeta na via adjacente. Com preenchimentos iguais, os canteiros receberam coberturas vegetais distintas: gramado (G), com uma única espécie de gramínia, e jardim (J), com forrações, herbáceas e arbustos diversos, predominantemente nativos. O experimento foi monitorado por um ano, entre março de 2012 e março de 2013, quando foram coletados os dados referentes ao seu funcionamento e eficiência em sete eventos chuvosos paulistanos. A compilação dessas informações permitiu a análise comparativa da qualidade da água dos escoamentos antes e depois da passagem pelos canteiros. Com recursos da FUNDEP, FCTH e LabVERDE, a pesquisa interdepartamental e interdisciplinar, desenvolvida numa cooperação entre a FAU-USP e a Escola Politécnica-USP, busca oferecer respostas às hipóteses com que trabalha a Arquitetura da Paisagem ao propor soluções naturalizadas de manejo dos escoamentos pluviais em complementação às técnicas convencionais atualmente empregadas nas cidades brasileiras, tomando a cidade de São Paulo como cenário. Como efeito do processo histórico de canalização do seu patrimônio hídrico, ocupação das áreas de várzea e impermeabilização, a população paulistana e da RMSP tem sofrido com enchentes que se agravam com o crescimento urbano e com a intensificação das chuvas. As soluções imediatistas para essa situação crítica seguem a práxis das obras convencionais de engenharia, que segregam a drenagem urbana dos processos ecológicos e hidrológicos e não contribuem para melhoria da qualidade ambiental dos escoamentos antes de destiná-los aos corpos hídricos superficiais, o que agrava o quadro generalizado de poluição dos rios e córregos urbanos. Os resultados do experimento prático atestam o desempenho da biorretenção na mitigação da poluição difusa, com reduções médias das cargas poluidoras acumuladas de 89,94% para o gramado e 95,49% para o jardim, que foi comprovadamente mais eficiente. Aliados ao estudo de tipologias paisagísticas já utilizadas com sucesso em outras cidades do mundo, esses resultados poderão corroborar o processo de transição na infraestrutura de São Paulo, respaldando tecnicamente e cientificamente as soluções investigadas de manejo das águas de chuva através da biorretenção no tratamento dos espaços abertos e na conformação de uma Infraestrutura Verde na cidade. / This thesis experimentally assesses the performance of bioretention systems in mitigating nonpoint-source pollution caused by runoff. A 1:1 scale experiment of a stormwater management facility was built in USP Campus based in São Paulo, SP. This prototype has been evaluated for one year, since March 2012, over its technical efficiency to improve water quality by analyzing runoff samples collected in its inlet and outlet. Combining landscape architecture and hydraulic engineering knowledge, this experiment consists of two independent vegetated plots connected to the gutter through a concrete channel, which drives the runoff into the facility from the avenue next to it. Each plot has its own spillway, where samples were collected for laboratory analysis under 22 water quality parameters and thus compared to gutter runoff. Regarding construction techniques, it was decided to apply simplified solutions without unnecessary expenses, but that ensured feasibility, solidity and isolation to the plots from the ground on all faces. As for filling the model, it was chosen to use the same material for both facilities, laid out from bottom to surface: 60cm of broken rocks, 15cm of gravel, coconut geotextile fabric, 5cm of coarse sand and, finally, 45 to 75cm of planting substrate with side slopes and covered with mulch. Regarding vegetation cover, two sets of plants have been used in the bioretention cells as a research strategy to compare the efficiency among different models in stormwater management, considering other issues in addition to improving the environmental quality of water, such as maintenance, adaptation and development of species and visual interest. Thus, the experiment plots were filled with the same substrate but with different vegetable toppings, according to the following configuration: mixed garden (M) - ground covers with predominance of native shrubs and herbaceous vegetation, and lawn (L) - covered only with emerald grass carpet (Zoysia japonica), which has been extensively used for lawns all over the country. This experimental model has provided scientific answers that attest the effectiveness of techniques using vegetated surfaces to retain and treat stormwater. Its results have attested the performance of bioretention for diffuse pollution mitigation, with average reductions of accumulated pollutant loads of 89.94% in the lawn (L) and 95.49% in the mixed garden (M), which wasproven to be more efficient. This research developed by USP Faculty of Architecture and Urbanism in partnership with Polythecnic School, does not aim to threat conventional methods of urban drainage in local cities, but to join them in the efforts of reaching solutions and technical knowledge that are suitable for urban ecosystems and harmless to environment and landscape.

No description available.

The contamination of rivers with nitrate from agricultural diffuse sources is not just a risk for ecosystems and their services, but also a health risk for water users. The Great Lakes (USA and Canada) are suffering from eutrophication problems. The Midwest is one of the richest farming land and one of the most productive areas on the planet. Thus, agriculture is one of the biggest drivers of local economies, accounting for billions of dollars of exports and thousands of jobs. The Midwest encompasses the Corn Belt region, a specialised system in corn production. Many of its agricultural basins drain into the Great Lakes. Corn requires a heavy amount of fertilizer to keep the best-yielding varieties. Some of the soils also require artificial drainage due to their low permeability, and to enable agriculture. The Cedar Creek watershed (CCW) in northeastern Indiana in the Corn Belt region is used as a case study area in this dissertation. Intensive agriculture in the CCW is characterised mainly by corn and soybean production. Tile drains are used, ejecting nitrate directly into the water. To find hotspots of nitrate is, then, crucial to avoid water quality deterioration. Identification of critical source areas of nitrate (CSAs) impairing waters is challenging. There are, mainly, two methodologies to identify hotspots of nitrate for the implementation of Best Management Practices (BMP): the targeting technique and the optimization approach. The targeting technique tends to identify hotspots based on loads of nitrate, omitting geomorphological watershed characteristics, costs for BMP implementation, and their spatial interactions. On the other hand, the parsimonious strategy does contemplate the trade-off of the economic and environmental contribution but requires sophisticated computational resources and it is more data-intense. This research presents a new framework based on the synergistic combination of both methodologies for the identification of CSAs in agricultural watersheds. Changes in watershed response due to alternative BMP applications were assessed using the model Soil and Water Assessment Tool (SWAT). Outputs in SWAT (nitrate export rates and nitrate concentration at the subbasin level) were used to evaluate the changes in water quality for the CCW. The newly developed targeting technique (HosNIT) considers SWAT outputs and intrinsic watershed parameters such as stream order, crop distance to the draining stream, and downstream nitrate enrichment/dilution effects within the river network. HosNIT establishes a workflow, based on a threshold system for the parameters considered, in order to spatially identify priority areas from where nitrate is reaching water. The more precise hotspots of nitrate are identified, the more improved the allocation of limited resources for conservation practices will be. HosNIT allows for a more spatially accurate CSAs identification, which enables a parsimonious optimization for BMP implementation. This parsimonious strategy will test BMP’s performance based on the environmental contribution and cost at the hotspots determined by HosNIT. The optimised solution for the CCW comes from the environmental contribution (decrease percentage of nitrate concentration at outlets) per dollar spent. For this case study means a year average of 3.7% of nitrate reduction with the optimised selection of scenarios for the studied period.

No description available.

No description available.

The expansion of Interstate 26 from Erwin, TN to the North Carolina border was a project that potentially adversely impacted South Indian Creek because of the steep landscapes and potential for erosion. Several studies have shown the short-term, negative effects of road construction on the water quality of nearby water bodies. Non-point source pollution is the major source of water pollution in the United States. The primary objective of this research is to evaluate the long-term effects of the construction of Interstate 26 on South Indian Creek to see if there has been any ecological recovery. The Environmental Health Sciences Laboratory of East Tennessee State University was contracted by the Tennessee Department of Transportation to collect data from before construction (1991-1992), during construction (1993-1994), and postconstruction (1995-1996). Comparison of microbial enzyme activities and other parameters to present-day (2012-2013) water quality conditions indicate that South Indian Creek has not fully recovered from the effects of the construction of the interstate.

Hui Wing-chi. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2001. / Includes bibliographical references (leaves 127-141). / Abstracts in English and Chinese. / LIST OF TABLES --- p.xi / LIST OF FIGURES --- p.xiii / LIST OF ACRONYMS --- p.xvii / Chapter CHAPTER ONE- --- INTRODUCTION / Chapter 1.1 --- Background --- p.1 / Chapter 1.2 --- Conceptual Framework and Study Objectives --- p.7 / Chapter 1.3 --- Scope of the Research and Study Area --- p.10 / Chapter 1.3.1 --- Location and Climate --- p.10 / Chapter 1.3.2 --- Geology --- p.12 / Chapter 1.3.3 --- Landuse Characteristics and Status of Water Quality --- p.13 / Chapter 1.4 --- Significance of Study --- p.14 / Chapter 1.5 --- Organization of Thesis --- p.16 / Chapter CHAPTER TWO - --- LITERATURE REVIEW / Chapter 2.1 --- Landuse Alteration --- p.17 / Chapter 2.1.1 --- Urbanization and Landuse Changes --- p.17 / Chapter 2.1.2 --- Detecting Landuse Changes in Urbanizing Region --- p.19 / Chapter 2.2 --- Impact of Landuse Alteration on Water Quality --- p.21 / Chapter 2.2.1 --- Point and Nonpoint Sources of Water Pollution --- p.22 / Chapter 2.2.2 --- Nonpoint Source Pollution as a Worldwide Environmental Problem --- p.23 / Chapter 2.2.3 --- Methods of Assessing Nonpoint Source Pollution --- p.24 / Chapter 2.2.4 --- GIS-based Modeling of Nonpoint Source Pollution --- p.26 / Chapter 2.2.5 --- Application of Remote Sensing on Water Quality Study --- p.27 / Chapter 2.3 --- Landuse Changes and Their Water Quality Impacts in the Pearl River Delta --- p.28 / Chapter 2.3.1 --- Economic Reform and Urbanization --- p.29 / Chapter 2.3.2 --- Urban Redevelopment --- p.31 / Chapter 2.3.3 --- Rural Industrialization --- p.33 / Chapter 2.3.4 --- Water Pollution --- p.34 / Chapter CHAPTER THREE - --- METHODOLOGY / Chapter 3.1 --- Introduction --- p.36 / Chapter 3.2 --- Computation of Areal Nonpoint Source Pollution Loading --- p.38 / Chapter 3.2.1 --- Assumptions --- p.38 / Chapter 3.2.2 --- Soil Conservation Service (SCS) Curve Number Method --- p.39 / Chapter 3.2.3 --- Generation of Nonpoint Source Pollutants --- p.42 / Chapter 3.2.4 --- Model Operation --- p.43 / Chapter 3.3 --- Instream Water Quality Modeling --- p.45 / Chapter 3.3.1 --- Description ofWASP5 --- p.46 / Chapter 3.3.2 --- Hydraulic Parameters --- p.47 / Chapter 3.3.3 --- Model Constants --- p.48 / Chapter 3.4 --- Description of Model Input Data --- p.49 / Chapter 3.4.1 --- Watershed Delineation --- p.49 / Chapter 3.4.2 --- Soil Data --- p.51 / Chapter 3.4.3 --- Rainfall Data --- p.52 / Chapter 3.4.4 --- Detection Landuse Changes --- p.53 / Chapter 3.4.4.1 --- Image Preprocessing --- p.54 / Chapter 3.4.4.2 --- Classification and Post-classification Analysis --- p.57 / Chapter 3.4.4.3 --- Assessment of Accuracy --- p.60 / Chapter 3.5 --- Scenario Modeling --- p.61 / Chapter CHAPTER FOUR - --- INTERFACING ARCVIE W GIS WITH WATER QUALITY MODEL / Chapter 4.1 --- Watershed Parameter Generator --- p.64 / Chapter 4.1.1 --- Topographic Analysis and Stream Network Definition --- p.65 / Chapter 4.1.2 --- Vectorization of Basin Geometries --- p.68 / Chapter 4.1.3 --- Computation of Basin Geometric Characteristics --- p.69 / Chapter 4.2 --- Nonpoint Source Pollution Loading Generator --- p.69 / Chapter 4.3 --- Instream Water Quality Calculator --- p.74 / Chapter CHAPTER FIVE- --- LANDUSE AND LAND COVER CHANGES ANALYSIS / Chapter 5.1 --- Framework for Analysis --- p.78 / Chapter 5.2 --- Landuse Changes During the Study Period --- p.82 / Chapter 5.2.1 --- Areal Landuse Changes --- p.82 / Chapter 5.2.2 --- Inter-category Landuse Changes --- p.86 / Chapter 5.2.2.1 --- Rural-to-urban Changes --- p.86 / Chapter 5.2.2.2 --- Rural-to-rural Changes --- p.87 / Chapter 5.2.3 --- Error matrix --- p.88 / Chapter 5.3 --- Spatial Pattern of Landuse and Land cover --- p.91 / Chapter 5.3.1 --- Urban Land --- p.92 / Chapter 5.3.2 --- Rural Areas --- p.94 / Chapter 5.4 --- Scenario Building --- p.96 / Chapter 5.5 --- Limitation of Landuse Classification based on Satellite Image Interpretation --- p.96 / Chapter 5.6 --- Summary --- p.98 / Chapter CHAPTER SIX - --- IMPACTS OF LANDUSE CHANGES ON NONPOINT SOURCE POLLUTION LOADING AND WATER QUALITY / Chapter 6.1 --- Impact of Landuse Changes on NPS Loading --- p.100 / Chapter 6.1.1 --- Identification of Curve Number --- p.100 / Chapter 6.1.2 --- Runoff and Areal Nonpoint Source Pollution Loadings --- p.101 / Chapter 6.1.3 --- Sensitivity of NPS Pollution Loading to Landuse Changes --- p.107 / Chapter 6.2 --- Instream Water Quality Analysis --- p.110 / Chapter 6.2.1 --- Downstream Variation of Water Quality --- p.111 / Chapter 6.2.2 --- Comparison with NWQC II --- p.114 / Chapter 6.3 --- Strategic Landuse Management --- p.117 / Chapter 6.4 --- Limitation of the Study --- p.118 / Chapter CHAPTER SEVEN - --- CONCLUSION / Chapter 7.1 --- Summary of Findings --- p.122 / Chapter 7.1.1 --- Landuse and Land Cover Changes --- p.122 / Chapter 7.1.2 --- GIS-based Water Quality Modeling --- p.123 / Chapter 7.1.3 --- Pollution Loading and Instream Water Quality --- p.124 / Chapter 7.2 --- Future Study --- p.125 / REFERENCES --- p.127