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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Skyfall i Sala : En skyfallskartering i HEC-RAS

Källbom, Jacob January 2023 (has links)
När klimatet i Sverige blir varmare ökar både förekomsten och omfattningen av intensiva skyfall. Dessa kan leda till stora konsekvenser lokalt för drabbade samhällen. Omfattande översvämningar, skadade fastigheter, erosionsskador och hindrad framkomlighet är några av de potentiella följderna. Ett första steg för att öka beredskapen för skyfall är att göra en skyfallskartering där ett nederbördstillfälle med skyfallskaraktär läggs in i en hydraulisk modell över ett område. Modellen visar sedan områden som riskerar att drabbas av översvämningar samt vilken väg som ytavrinningen tar under förloppet. I detta arbete har en sådan modell gjorts över Sala stad. Skyfallsmodellen skapades i programmet HEC-RAS och för att simulera infiltrationen användes metoden SCS curve number. SCS curve number metoden uppskattar infiltration baserat på markanvändning och jordart. Typregnet valdes till 100 års återkomsttid och modellerades som ett CDS-regn med varaktighet sex timmar och klimatfaktor 1,3. Ett avdrag på nederbördsmängden gjordes även för dagvattennätets kapacitet. Resultatet blev att flertalet områden i Sala kan drabbas av potentiellt stora vattendjup. De största problemområdena identifierades till bebyggelsen mellan Ringgatan och Östra Tulegatan söder om centrala Sala samt området kring Pråmån uppströms Jakob Mats kvarn. Då infiltrationsmetoden SCS curve number är baserad på empiriska data gjordes en känslighetsanalys på infiltrationsparametrarna. Det som undersöktes var påverkan på total andel infiltrerad nederbörd och översvämningarnas utbredning. Tre olika scenarion baserat på osäkerheten i curve number-talet användes samt ett scenario utan infiltration i modellen. Skillnaden i total översvämmad yta med ett djup större än 0,1 m mellan scenariot med högst infiltration och scenariot med lägst infiltration var i modellen totalt 9,1 procentenheter. I det scenario där ingen infiltration modellerades drabbades flertalet nya fastigheter och infrastruktur av översvämning vilket visar på infiltrationens betydelse för riskbedömningen vid en skyfallskartering. Totalt infiltrerade 30 % av nederbörden i modellen vid scenariot med lägst infiltration, 49 % av nederbörden vid scenariot med direkta litteraturvärden för curve number- talet och 66 % av nederbörden i scenariot med högst infiltration. Eftersom infiltrationen mellan scenarierna til hög grad berodde på hur jordarterna klassades i modellen är det dock svårt att dra en generell slutsats om vilket infiltrationsscenario som är bäst lämpat att använda vid skyfall. / As the climate becomes warmer in Sweden the frequency and extent of cloudbursts are expected to rise. When these rain events occurs in populated areas the consequences can be severe for the local community with extensive flooding leading to for example damaged properties, erosion and obstructions of traffic. One step to increase the awareness of these risks is to do a cloudbust mapping were a rain with cloudburst extent is modelled hydraulically. Areas that are at risk of flooding during the rain event and flow paths for the surface runoff can be assessed from the model. In this thesis such a model was created for the town of Sala. The cloudbust model was made using the software HEC-RAS and to simulate infiltration the method SCS curve number was implemented. The rain event was modeled as a Chicago design storm with a return period of 100 years, total duration of six hours and a climate factor of 1,3. The results were that several areas in Sala were at risk of flooding. Two main areas with risk of major flooding extents were located to just south of central Sala between Ringgatan and Östra Tulegatan and adjacent to Pråmån upstream of Jakob Mats kvarn. Because of uncertainties in the SCS curve number model and due to the fact that it is based on empirical data a sensitivity analysis was also done on the infiltration parameters. For the sensitivity analysis four different scenarios were used. One scenario had no modeled infiltration and the three other scenarios were based of error estimations of the curve number parameter called antecedent runoff conditions. The difference in flooding extent with a depth greater than 0,1 m in the model between the scenario with high infiltration and the scenario with low infiltration was 9,1 percentage points. Several new properties and infrastructure were affected in the scenario when no infiltration was used. In total 30% of the precipitation infiltrated in the model in the scenario with low infiltration, 49% infiltrated in the scenario with literature values for the curve number value, and 66% of the precipitation infiltrated in the scenario with high infiltration. Since the infiltration is highly dependent on the classification of the soils in the model no overall conclusion could be drawn on which infiltration scenario that is best suited for a cloudburst model in general when the SCS curve number method is used to model infiltration.
12

Surface water hydrologic modeling using remote sensing data for natural and disturbed lands

Muche, Muluken Eyayu January 1900 (has links)
Doctor of Philosophy / Department of Biological & Agricultural Engineering / Stacy L. Hutchinson / The Soil Conservation Service-Curve Number (SCS-CN) method is widely used to estimate direct runoff from rainfall events; however, the method does not account for the dynamic rainfall-runoff relationship. This study used back-calculated curve numbers (CNs) and Normalized Difference Vegetation Index (NDVI) to develop NDVI-based CNs (CN[subscript]NDV) using four small northeastern Kansas grassland watersheds with average areas of 1 km² and twelve years (2001–2012) of daily precipitation and runoff data. Analysis indicated that the CN[subscript]NDVI model improved runoff predictions compared to the SCS-CN method. The CN[subscript]NDVI also showed greater variability in CNs, especially during growing season, thereby increasing the model’s ability to estimate relatively accurate runoff from rainfall events since most rainfall occurs during the growing season. The CN[subscript]NDVI model was applied to small, disturbed grassland watersheds to assess the model’s ability to detect land cover change impact for military maneuver damage and large, diverse land use/cover watersheds to assess the impact of scaling up the model. CN[subscript]NDVI application was assessed using a paired watershed study at Fort Riley, Kansas. Paired watersheds were identified through k-means and hierarchical-agglomerative clustering techniques. At the large watershed scale, Daymet precipitation was used to estimate runoff, which was compared to direct runoff extracted from stream flow at gauging points for Chapman (grassland dominated) and Upper Delaware (agriculture dominated) watersheds. In large, diverse watersheds, CN[subscript]NDVI performed better in moderate and overall flow years. Overall, CN[subscript]NDVI more accurately simulated runoff compared to SCS-CN results: The calibrated model increased by 0.91 for every unit increase in observed flow (r = 0.83), while standard CN-based flow increased by 0.506 for every unit increase in observed flow (r = 0.404). Therefore, CN[subscript]NDVI could help identify land use/cover changes and disturbances and spatiotemporal changes in runoff at various scales. CN[subscript]NDVI could also be used to accurately estimate runoff from precipitation events in order to instigate more timely land management decisions.
13

A combined field data and empirical modeling approach to precipitation-runoff analysis in an agro-forested Prairie watershed

Petzold, Halya 04 June 2015 (has links)
Low relief, heavily human-impacted landscapes like those of the Prairies in south-central Canada have received little attention in previous hydrological research. Here, the rainfall-runoff relationship in the context of both a field-based investigation and an empirical model is examined in an effort to provide insight into Prairie hydrology. Rainfall and water level data were collected for nested sub-watersheds of the Catfish Creek watershed, a 642 km2, near-level, mixed land use and engineered Prairie watershed. First, the dataset is examined for runoff controls. Second, the history of the United States Curve Number Method is reviewed and its initial abstraction ratio examined against collected field data to determine the applicability of a single, constant ratio to Prairie landscapes. Overall, the results indicate that Prairie runoff generation processes differ significantly from those of humid, pristine catchments of higher relief and a conceptual model is proposed with that regards.
14

Enhancement and Evaluation of a Rainfall-Runoff Single Event Model

Salazar Mejia, Germania 12 May 2012 (has links)
Planning and design of stormwater facilities (including best management practices and low impact development) involve the calculation of peak flows and runoff volumes. Rainfall-runoff models are frequently utilized to estimate this information. A userriendly rainfall-runoff tool (LIDIA) was developed using Visual Basic for Applications in Microsoft Office Excel. This research showed comprehensive guidelines on how to setup a model in LIDIA and reported the first evaluation of LIDIA using field data. LIDIA hydrologic module was tested using 10-minute rainfall, land cover, soil series, land cover management, and runoff data from two small watersheds in North Mississippi. Eleven storm events, over a period of seven months were used for the one evaluation site and 11 storm events were used for the second case study. Overall the development and results of LIDIA tool showed in this study are positive in keeping the enhancement of the model.
15

Determinação de parâmetros hidrológicos por técnicas de sensoriamento remoto em macrodrenagem urbana / Determination of hydrological parameters by remote sensing techniques in urban macrodrainage

Martins, Leandro Guimarães Bais 11 May 2012 (has links)
Nos centros urbanos, as precipitações sempre estiveram ligadas a problemas como inundações e propagação de doenças. Para solucioná-los, é comum a realização de obras hidráulicas nos sistemas de drenagem urbanos. Para tanto, deve-se conhecer as condições da bacia hidrográfica e as consequências que qualquer alteração no ambiente pode causar. Portanto, modelos hidrológicos são utilizados na previsão do comportamento das bacias frente a eventos de precipitação, aumentando a eficácia das obras e diminuindo os riscos associados a estas. Para o uso de modelos, são necessários diversos parâmetros hidrológicos referentes à bacia, tais como área de drenagem, comprimento e declividade dos talvegues, tipo de cobertura de solo etc. Com o avanço da tecnologia, a determinação destes torna-se cada vez mais precisa, bem como os modelos utilizados, trazendo o Sistema de Informações Geográficas (SIG) e o sensoriamento remoto como poderosas ferramentas de apoio a estudos hidrológicos. Neste trabalho, aplicou-se o processo de classificação automática supervisionada pelo método da Análise Orientada a Objeto a uma imagem de satélite de alta resolução da bacia hidrográfica do córrego do Gregório, para caracterizar sua cobertura de solo e determinar os parâmetros hidrológicos número de deflúvio (CN, pelo método do SCS), grau de vegetação (PP), área (A), comprimento (L) e declividades dos talvegues (S) das sub-bacias que compõem a bacia, para as quais os resultados obtidos foram bastante satisfatórios. Por fim, atualizou-se o modelo hidrológico EESC (1993), referente ao sistema de macrodrenagem de São Carlos, obtendo-se hidrogramas finais com diferenças, em relação ao modelo original, de até 33,96% para vazão de pico (Qp), 77,78% para tempo de pico (tp) e 29,86% para volume total de escoamento. / In urban centers, precipitation always been related to problems such as floods and spread of disease. To solve them, it is common to make hydraulic interventions in the urban drainage systems. For this, it is necessary to know the conditions of the watershed and the consequences that any change in the environment can cause. Therefore, hydrological models are used to predict the river behavior in opposite to precipitation events, increasing the efficiency of the hydraulic interventions and reducing the associated risks to these. For the use of models, it is necessary to have several hydrological parameters related to the basin such as drainage area, river length, slope of the thalweg, type of soil cover etc. Trough the technological advancement, the parameter determination becomes more accurate as well as the models, and the Geographic Information System (GIS) and remote sensing appear as powerful tools to support hydrological studies. In this study, we have applied the automatic supervised classification process by the Object-Oriented Analysis method to a high resolution satellite image of the córrego do Gregório watershed, to classify soil coverage and to determine the hydrological parameters curve-number (CN by the SCS method), vegetation degree (PP), area (A), length (L), and slope of thalwegs (S) of the sub-basins of the córrego do Gregório watershed, for which the results were quite satisfactory. Finally, a hydrological model for the São Carlos macrodrainage system called EESC model (1993) was updated with the new parameters, obtaining final hydrographs with differences from the original model up to 33.96% for peak discharge (Qp), 77.78% for peak time (tp) and 29.86% for total volume of runoff.
16

Simulação e gestão da disponibilidade hídrica em bacia hidrográfica representativa do bioma Cerrado / Simulation and management of water availability in basin representative of the cerrado biome

Gotardo, Jackeline Tatiane 10 February 2011 (has links)
Made available in DSpace on 2017-07-10T19:25:24Z (GMT). No. of bitstreams: 1 Jackeline Gotardo parte 1.pdf: 5941044 bytes, checksum: e7a46324b06508bcbeab16411c56e75d (MD5) Previous issue date: 2011-02-10 / The simulation study of water availability and management of the basin was addressed in two ways. First estimate the water demand in climatological experimental catchment representative of the Savannah. Defined by the difference in the occurrence of potential evapotranspiration and precipitation minimal likely to occur on a scale ten days. In the estimation of potential evapotranspiration compared to the empirical equations of the methods Blaney-Criddle, Hargreaves, ASCE Penman-Monteith, Penman, Priestley-Taylor method with the standard Penman-Monteith FAO 56. The method presented Blaney-Criddley is recommended when there is limited availability of climatological data. To estimate the probability distribution used the gamma distribution for the time series of precipitation and evapotranspiration and precipitation time series with zero values, we used the incomplete gamma function. The adhesion of the estimated probabilities to the observed data was verified by testing, non-parametric Kolmogorov-Smirnov test, with significance level (α-0, 05) which fitted well the model distributions. The occurrence of precipitation and evapotranspiration decendial likely P (X ≥ x) for different probability levels showed drought periods of ten days between 4:32, with critical values 25-39 mm, on a scale ten days, the months from May to September. In a second stage it was considered the the reservoir of soil water management and proposes a model allowing to calculate the irrigation water demand of crops of beans and corn planting dates in two different in drought and rainy. The bowl was hydrology by the method of the turn number (CN). Simulated the water demand and availability required in ascertaining what is the risk of meeting the irrigated area. The proposed model was effective for water management in the basin throughout the year. It was found that corn and beans require different amounts of water throughout the year, and that optimizing the additional water demand is a management tool able to minimize conflicts over water use. hydrology of the basin presents risks of not having met the demand required in the dry period is necessary to establish infraestrurura water for water storage / O estudo da simulação e da gestão da disponibilidade hídrica da bacia foi abordado de duas formas. Primeiramente, foi estimada a demanda hídrica climatológica em bacia hidrográfica experimental representativa do Cerrado, definido pela diferença da ocorrência da evapotranspiração potencial e precipitação mínima provável de ocorrer, em escala decendial. Na estimativa da Evapotranspiração potencial comparou-se as equações empíricas dos métodos Blaney-Criddle, Hargreaves, Penman-Monteith ASCE, Penman, Priestley-Taylor com o método padrão de Penman-Monteith FAO 56. O método Blaney- Criddley é recomendado quando há limitação na disponibilidade de dados climatológicos. Para estimativa da distribuição de probabilidade, utilizou-se a distribuição gama para a série histórica de precipitação e evapotranspiração e, para série histórica de precipitação com valores nulos, utilizou-se a função gama incompleta. A aderência das probabilidades estimadas aos dados observados foi verificada através do teste, não-paramétrico, de Kolmogorov-Smirnov, com nível de significância (􀄮-0,05), o qual ajustou-se bem aos modelos de distribuições. A ocorrência de precipitação e evapotranspiração decendial provável P (X 􀂕 x) para diferentes níveis de probabilidades demonstrou déficit hídrico entre os decêndios 4 e 32, apresentando valores críticos de 25 a 39 mm, em escala decendial, nos meses de maio a setembro. Em um segundo momento, considerou-se o reservatório de água do solo propondo um modelo de manejo de irrigação permitindo calcular a demanda hídrica das culturas de feijão e milho em duas datas de plantio diferentes em período de seca e chuvoso. O comportamento hidrológico da bacia foi através do método do número da curva (CN). Simulou-se a demanda hídrica requerida e a disponibilidade, averiguando qual o risco de atender a área irrigada. O modelo proposto foi eficaz para a gestão hídrica da bacia ao longo do ano. Verificou-se que culturas de milho e feijão requerem diferentes quantidades de água ao longo do ano e que a otimização pela demanda hídrica complementar é um instrumento de gestão capaz de minimizar conflitos pelo uso da água. O comportamento hidrológico da bacia apresenta riscos de não ter a demanda requerida atendida no período seco, sendo necessário a implantação de infraestrutura hídrica para armazenamento de água
17

Simulação e gestão da disponibilidade hídrica em bacia hidrográfica representativa do bioma Cerrado / Simulation and management of water availability in basin representative of the cerrado biome

Gotardo, Jackeline Tatiane 10 February 2011 (has links)
Made available in DSpace on 2017-05-12T14:48:47Z (GMT). No. of bitstreams: 1 Jackeline Gotardo parte 1.pdf: 5941044 bytes, checksum: e7a46324b06508bcbeab16411c56e75d (MD5) Previous issue date: 2011-02-10 / The simulation study of water availability and management of the basin was addressed in two ways. First estimate the water demand in climatological experimental catchment representative of the Savannah. Defined by the difference in the occurrence of potential evapotranspiration and precipitation minimal likely to occur on a scale ten days. In the estimation of potential evapotranspiration compared to the empirical equations of the methods Blaney-Criddle, Hargreaves, ASCE Penman-Monteith, Penman, Priestley-Taylor method with the standard Penman-Monteith FAO 56. The method presented Blaney-Criddley is recommended when there is limited availability of climatological data. To estimate the probability distribution used the gamma distribution for the time series of precipitation and evapotranspiration and precipitation time series with zero values, we used the incomplete gamma function. The adhesion of the estimated probabilities to the observed data was verified by testing, non-parametric Kolmogorov-Smirnov test, with significance level (α-0, 05) which fitted well the model distributions. The occurrence of precipitation and evapotranspiration decendial likely P (X ≥ x) for different probability levels showed drought periods of ten days between 4:32, with critical values 25-39 mm, on a scale ten days, the months from May to September. In a second stage it was considered the the reservoir of soil water management and proposes a model allowing to calculate the irrigation water demand of crops of beans and corn planting dates in two different in drought and rainy. The bowl was hydrology by the method of the turn number (CN). Simulated the water demand and availability required in ascertaining what is the risk of meeting the irrigated area. The proposed model was effective for water management in the basin throughout the year. It was found that corn and beans require different amounts of water throughout the year, and that optimizing the additional water demand is a management tool able to minimize conflicts over water use. hydrology of the basin presents risks of not having met the demand required in the dry period is necessary to establish infraestrurura water for water storage / O estudo da simulação e da gestão da disponibilidade hídrica da bacia foi abordado de duas formas. Primeiramente, foi estimada a demanda hídrica climatológica em bacia hidrográfica experimental representativa do Cerrado, definido pela diferença da ocorrência da evapotranspiração potencial e precipitação mínima provável de ocorrer, em escala decendial. Na estimativa da Evapotranspiração potencial comparou-se as equações empíricas dos métodos Blaney-Criddle, Hargreaves, Penman-Monteith ASCE, Penman, Priestley-Taylor com o método padrão de Penman-Monteith FAO 56. O método Blaney- Criddley é recomendado quando há limitação na disponibilidade de dados climatológicos. Para estimativa da distribuição de probabilidade, utilizou-se a distribuição gama para a série histórica de precipitação e evapotranspiração e, para série histórica de precipitação com valores nulos, utilizou-se a função gama incompleta. A aderência das probabilidades estimadas aos dados observados foi verificada através do teste, não-paramétrico, de Kolmogorov-Smirnov, com nível de significância (􀄮-0,05), o qual ajustou-se bem aos modelos de distribuições. A ocorrência de precipitação e evapotranspiração decendial provável P (X 􀂕 x) para diferentes níveis de probabilidades demonstrou déficit hídrico entre os decêndios 4 e 32, apresentando valores críticos de 25 a 39 mm, em escala decendial, nos meses de maio a setembro. Em um segundo momento, considerou-se o reservatório de água do solo propondo um modelo de manejo de irrigação permitindo calcular a demanda hídrica das culturas de feijão e milho em duas datas de plantio diferentes em período de seca e chuvoso. O comportamento hidrológico da bacia foi através do método do número da curva (CN). Simulou-se a demanda hídrica requerida e a disponibilidade, averiguando qual o risco de atender a área irrigada. O modelo proposto foi eficaz para a gestão hídrica da bacia ao longo do ano. Verificou-se que culturas de milho e feijão requerem diferentes quantidades de água ao longo do ano e que a otimização pela demanda hídrica complementar é um instrumento de gestão capaz de minimizar conflitos pelo uso da água. O comportamento hidrológico da bacia apresenta riscos de não ter a demanda requerida atendida no período seco, sendo necessário a implantação de infraestrutura hídrica para armazenamento de água
18

Systém přírodě blízkých protierozních a protipovodňových opatření a jejich optimalizace v procesu pozemkových úprav. / System near natural erosion and flood control measures and optimization of the process of land consolidation.

BLÁHA, Vladimír January 2013 (has links)
The thesis is focused on the system erosion and the flood control measures in the cadastral territory of Smetanova Lhota. For the calculation of the erosion threat was used universal soil loss equation (USLE) and runoff characteristics are calculated using the runoff CN - curves. The proposal has the influence of several factors. It's rainfall, vegetation cover, soil characteristics, morphology and other. Several calculations were carried out using the program ERCN.
19

Hur påverkar en övergång från konventionell plöjning till reducerad jordbearbetning avrinning från åkermark / How does a transition from conventional plowing to reduced tillage affect runoff from arable soil

Nilsson, Johan January 2018 (has links)
Jordbruk syftar till användandet av mark för produktion av livsmedel, foder och råvaror. Reducerad jordbearbetning uppstod ursprungligen under 1900-talet för att öka lönsamheten till följd av stigande priser på drivmedel. För att sänka förbrukningen av drivmedel började bönder att bearbeta åkermarken i grundare skikt. Inom det moderna jordbruket finns det en pågående trend där en övergång från den konventionella plöjningen till reducerade bearbetningsmetoder blir allt vanligare. Idag pågår det kontinuerlig forskning som försöker tydliggöra hur olika bearbetningsmetoder påverkar jordbruksmarkens struktur. Det finns även teorier som pekar på att en övergång från konventionell plöjning till reducerad jordbearbetning kan minska mängden avrinning från åkermark, men trots det är området fortfarande relativt outforskat. Skador till följd av avrinning från kraftiga nederbördstillfällen har under modern tid ökat. I framtida prognoser förutspås det en fortsatt ökning och mer omfattande skador. Med anledning av detta kommer en bättre klimatanpassning att krävas för att minska skador som uppstår till följd av avrinning. Ett exempel på den växande problematiken inträffade 2015 i Hallsberg. Den femte september anlände ett lågtryck som förde med sig över 100 mm nederbörd. Till följd av den extrema mängden nederbörd uppstod det omfattande översvämningar i Hallsberg och på närliggande åkermarker. Från händelsen växte frågan hur en övergång från plöjning till reducerat jordbruk påverkar avrinning fram som studien syftar till att undersöka. Strategin som användes för att nå målet med studien bestod dels av en litteraturstudie samt hydrologiska modelleringar för olika jordbearbetnings metoder i programmet HEC-HMS. I litteraturstudien sammanställdes vetenskapliga studier som jämfört den fysikaliska inverkan som jordbruksmetoder har på åkermark. De hydrologiska modelleringarna baserades på information från Lantmäteriet, mätningar från tidigare undersökningar och SCS runoff curve number method (kurvnummer). Resultatet från litteraturstudien och de hydrologiska modelleringarna sammanvägdes i slutet av studien och från resultatet kunde ingen slutsats dras om hur en övergång från konventionell till reducerad jordbearbetning påverkar avrinning. För att kunna dra en slutsats behövde ett bredare vetenskapligt underlag samt en mer utvecklad modell. / Farming aims towards the utilization of soil for production of food, animal fodder and commodities. In today’s agriculture, we begin to see a gradual transition from the conventional plowing methods to reduced tillage methods. The concept of the reduced tillage originally arose to increase the profitability in agriculture as a response to the rising fuel price. To reduce the fuel consumption farmers began to cultivate the arable soil in more shallow layers. Today researchers are also trying to map how different tillage methods are affecting the soil structure in the arable soil. There are also some scientific theories which point out that a transition from conventional plowing to reduced tillage can reduce runoff from arable land, but despite the interest, the area is still relatively unexplored. Runoff due to heavy rainfall has in modern time increased. In future climate forecasts, the rainfall is predicted to increase even more. As a response to the increased rainfall, the amount of runoff will be higher and with that more extensive damages will occur. In response to these developments, the requirements for climate adjustment will increase in order to minimize the potential damage caused by runoff and flooding events. An example of this growing problem occurred in 2015 in Hallsberg. Between 5 and 6 September, a low-pressure weather system brought down about 100 mm of precipitation. Due to the extreme amount of the rainfall, large floods occurred all over Hallsberg as well as in the nearby arable land. From this event, the question of how a transition from conventional plowing methods to reduced tillage affects the runoff from rainfall emerged. The strategy used for the study consisted of a literature review and hydrological modeling for various soil tillage methods in the program HEC-HMS. In the literature review, scientific studies that compared the physical soil impact from different farming method were compiled. The basis for the hydrological model was created on collected information from the Swedish mapping, cadastral and land registration authority, the literature study and SCS runoff curve method. No clear conclusion could be drawn from the study. To be able to draw a conclusion from the compiled literature and the hydrological model a broader basis of scientific literature and a more developed model was needed.
20

Determinação de parâmetros hidrológicos por técnicas de sensoriamento remoto em macrodrenagem urbana / Determination of hydrological parameters by remote sensing techniques in urban macrodrainage

Leandro Guimarães Bais Martins 11 May 2012 (has links)
Nos centros urbanos, as precipitações sempre estiveram ligadas a problemas como inundações e propagação de doenças. Para solucioná-los, é comum a realização de obras hidráulicas nos sistemas de drenagem urbanos. Para tanto, deve-se conhecer as condições da bacia hidrográfica e as consequências que qualquer alteração no ambiente pode causar. Portanto, modelos hidrológicos são utilizados na previsão do comportamento das bacias frente a eventos de precipitação, aumentando a eficácia das obras e diminuindo os riscos associados a estas. Para o uso de modelos, são necessários diversos parâmetros hidrológicos referentes à bacia, tais como área de drenagem, comprimento e declividade dos talvegues, tipo de cobertura de solo etc. Com o avanço da tecnologia, a determinação destes torna-se cada vez mais precisa, bem como os modelos utilizados, trazendo o Sistema de Informações Geográficas (SIG) e o sensoriamento remoto como poderosas ferramentas de apoio a estudos hidrológicos. Neste trabalho, aplicou-se o processo de classificação automática supervisionada pelo método da Análise Orientada a Objeto a uma imagem de satélite de alta resolução da bacia hidrográfica do córrego do Gregório, para caracterizar sua cobertura de solo e determinar os parâmetros hidrológicos número de deflúvio (CN, pelo método do SCS), grau de vegetação (PP), área (A), comprimento (L) e declividades dos talvegues (S) das sub-bacias que compõem a bacia, para as quais os resultados obtidos foram bastante satisfatórios. Por fim, atualizou-se o modelo hidrológico EESC (1993), referente ao sistema de macrodrenagem de São Carlos, obtendo-se hidrogramas finais com diferenças, em relação ao modelo original, de até 33,96% para vazão de pico (Qp), 77,78% para tempo de pico (tp) e 29,86% para volume total de escoamento. / In urban centers, precipitation always been related to problems such as floods and spread of disease. To solve them, it is common to make hydraulic interventions in the urban drainage systems. For this, it is necessary to know the conditions of the watershed and the consequences that any change in the environment can cause. Therefore, hydrological models are used to predict the river behavior in opposite to precipitation events, increasing the efficiency of the hydraulic interventions and reducing the associated risks to these. For the use of models, it is necessary to have several hydrological parameters related to the basin such as drainage area, river length, slope of the thalweg, type of soil cover etc. Trough the technological advancement, the parameter determination becomes more accurate as well as the models, and the Geographic Information System (GIS) and remote sensing appear as powerful tools to support hydrological studies. In this study, we have applied the automatic supervised classification process by the Object-Oriented Analysis method to a high resolution satellite image of the córrego do Gregório watershed, to classify soil coverage and to determine the hydrological parameters curve-number (CN by the SCS method), vegetation degree (PP), area (A), length (L), and slope of thalwegs (S) of the sub-basins of the córrego do Gregório watershed, for which the results were quite satisfactory. Finally, a hydrological model for the São Carlos macrodrainage system called EESC model (1993) was updated with the new parameters, obtaining final hydrographs with differences from the original model up to 33.96% for peak discharge (Qp), 77.78% for peak time (tp) and 29.86% for total volume of runoff.

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