Dissertations / Theses on the topic 'Hydrology'
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Midttømme, Grethe Holm. "Flood Handling and Emergency Action Planning for Dams." Doctoral thesis, Norwegian University of Science and Technology, Department of Hydraulic and Environmental Engineering, 2002. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-531.
Full textEven though dams are designed to bypass floods of significant magnitudes, floods less severe than the design flood may pose a threat to dams. Ongoing research into climate change also shows an increasing trend towards severe floods, that is an increased probability of floods exceeding the present design floods. Therefore, acquiring understanding of floods and risk reduction measures to mitigate any of their undesired effects is of great importance. Dam safety management in Norway has moved towards active use of risk analyses. At the same time, emergency planning and exercises are emphasized as necessary tools for handling abnormal situations such as severer floods. Few dam safety experts or dam owners have experienced large floods, which makes it difficult to assess the complexity of floods. Floods may also be difficult to assess fully by means of traditional risk analyses, as these normally focus on single dams. Floods have a certain geographical extent and must be expected to occur simultaneously in a system of dams and reservoirs.
This thesis hopes to extend knowledge of floods and dam safety. The main conclusion of a literature review of risk analysis and emergency planning is that human factors must be a focus. This is further supported by findings from the case studies of hazard floods. Emergency planning and exercises are believed to be of major importance to successful flood handling, but a survey of status for these issues in Norway shows that there is still work to be done. Many dam owners have not managed to start developing emergency action plans nor carry out emergency exercises. Not surprisingly, most of these are municipalities and private citizens, typical owners of smaller dams. Further revision of the emergency planning guidelines should take these findings into consideration. The authorities should bear in mind the need for alternative approaches to encourage these dam owners to develop emergency action plans. Possible problems related to development trends in our society also deserve attention, such as increased focus on cost-effective organizations at the expense of safety and the need for robust organizations and technical systems to handle future emergencies.
Thoms, R. Brad. "Simulating fully coupled overland and variably saturated subsurface flow using MODFLOW /." Full text open access at:, 2003. http://content.ohsu.edu/u?/etd,16.
Full textMatheussen, Bernt Viggo. "Effects of anthropogenic activities on snow distribution, and melt in an urban environment." Doctoral thesis, Norwegian University of Science and Technology, Faculty of Engineering Science and Technology, 2004. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-243.
Full textIn many parts of the world snow melt runoff influence discharge from combined sewer overflows (CSO) and flooding in urban drainage systems. Despite this, urban snow hydrology is a field that has received little attention from the urban drainage community. The objectives of this research were to better understand urban snow hydrology and through field work and hydrological modelling quantify effects of anthropogenic activities (AA) on snow distribution, and melt in an urban environment. This means in principle how the presence (design geometry) and operation of roads and buildings influence the snow distribution and melt in urban areas. The Risvollan urban catchment (20 ha) located in Trondheim, Norway, was used as a study area. A literature review of urban snow hydrology was also carried out.
A gridded urban hydrology model (GUHM) was developed as part of the study. The principal idea of the GUHM is to subdivide an urban catchment into orthogonal equal area grid cells. The snow routine in the GUHM is based on an energy balance approach, which together with a soil-runoff routine is used to calculate a time series of rain, snow water equivalent (SWE), snow melt, and runoff, for each grid cell. In GUHM, processes such as snow clearing of roads, locally low albedos, heat/shadowing from buildings, and effects of slope and aspect are included in the model structure.
A technique for observing time series of snow covered area (SCA) for an urban catchment is presented. The method is based on image processing and neural network technology to calculate SCA from a time series of images taken from a tall building in the Risvollan catchment. It was shown that SCA on roads and roofs in general becomes more rapidly snow free during melt periods compared to the park areas of the Risvollan catchment. This can be explained by snow clearing of roads, snowdrift from roofs and high snow melt rates on roofs and roads. The high melt rates was attributed to locally low albedos in vicinity to roads, rooftop snow packs exposure to wind and solar radiation, in addition to anthropogenic heat release from the roofs themselves.
Field observations of SWE were carried out in the Risvollan catchment and it was shown that areal mean SWE located on/or nearby roads and buildings were significantly lower during mid and end of the winter, than in park areas. This can be attributed to higher melt rates caused by AA. A time series of SCA and SWE was obtained through field work for the period from 2000 to 2003 in the Risvollan catchment.
The GUHM was applied and calibrated for the Risvollan catchment for a three year period. Two seasons were used as validation period. Comparison between the simulated and observed SWE, SCA and runoff data showed that the GUHM was able to simulate snow accumulation and melt for whole seasons with short time resolution (1 hour) satisfactory.
The GUHM was used to quantify effects of AA on snow distribution and melt for six different land use scenarios in the Risvollan catchment for the period June 1998 to June 2003. The modelling results showed that when the area coverage of buildings and roads increased, the SCA and SWE more rapidly decreased during melt periods. Because of this more runoff will be produced in the early winter season (Jan-March) compared to if the catchment had been covered with only sparsely vegetated areas.
The simulation results showed that when the impervious surface covers of a catchment increase, the peak and volume runoff will also increase, as expected.
Both the field observations and the hydrological model study carried out in this work showed that AA lowers SCA and SWE more rapidly in an urban environment compared to more untouched terrain. The reasons for this are redistribution of snow, and strong snow melt rates on roads, roofs, and in snow deposit areas. Low albedos and anthropogenic heat release are the main reasons for the enhanced snow melt rates.
Røhr, Paul Christen. "A hydrological study concerning the southern slopes of Mt Kilimanjaro, Tanzania." Doctoral thesis, Norwegian University of Science and Technology, Faculty of Engineering Science and Technology, 2003. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-239.
Full textThe hydrological conditions on the southern slopes of Mt Kilimanjaro, Tanzania, are complex and not similar to very many other places. High annual precipitation with complex distribution patterns occurs on these slopes. Extensive water consumption and concentrated groundwater sources of unknown origin are found on the plains. The distribution and utilisation of the scarce water resources can easily be influenced by change in these and in other factors. A hydrological model is developed for the area and used for studying these processes and their influence on potential change in land use and climate.
This study is a part of a cooperative project between the University of Dar es Salaam, Tanzania and the Norwegian University of Science and Technology in Trondheim, Norway, focusing on how changes in land use influence the hydrologic -al responses of a catchment.
Extensive fieldwork has been performed in the course of several stays in the area. Three gauging stations were established on the slopes south of Mt Kilimanjaro for gauging the runoff from areas with and without influence from human activities. Precipitation and temperature measurements from the lower boundary of the forest reserve and up to 4000 metres above sea level (masl) were performed. Extensive field surveys were performed for identifying and understanding the hydrological processes taking place in the catchment. In addition, hydrological data were collected from the regular observation network.
The stream gauging and the precipitation measurements were analysed. The results were used in a water balance assessment of the southern slopes of Mt Kilimanjaro for determination of the extent of infiltration in the higher areas. Based on the results from the three sub-studies, a hydrological model was developed which describes the vertical water balance above and in the soil zone. The model can be used for investigation of the hydrological impact of changes in land use or climate. The model takes meteorological data as an input in addition to parameters describing the land cover and water demand in the catchment. This was applied for analysing the impact of prospective land use and climate changes.
The analysis of the discharge data and field inspections indicated that no surface runoff comes from the area above 2800 masl. The study of the precipitation data resulted in a function describing the relative distribution of precipitation according to elevation for the southern slopes of Mt Kilimanjaro. The analysis indicates that the maximum precipitation intensity occurs about 400-500 meters higher than previously assumed. The water balance assessment gave indications on the extent of the deep groundwater infiltration on the southern slopes of Mt Kilimanjaro.
These findings were incorporated into the hydrological model, which was calibrated for three catchments on the southern slopes of Mt Kilimanjaro. The calibration for a small 21 km2 uphill catchment, a mid-hill 52 km2 catchment and a large 1783 km2 catchment reaching from the plains to the peak of Mt Kilimanjaro showed good accordance between the simulated and the observed discharge for the three catchments.
The calibrated model was successfully used for simulating the period from 1958 to 2000 for the large catchment and showed good accordance for the simulation period. Simulations with changes in forest cover, water demand and climate were performed. The climate changes simulated were based on the findings from the Intergovernmental Panel on Climate Change and land use and forest cover and were evaluated on the basis of potential management schemes. The simulations indicate that the water demand in the area is not being met, and that changes in water demand are not fully reflected in the river discharge. The results also show that the changes have greater influence in years where the water deficit is already substantial, so called “dry years”, than in years with a smaller deficit.
The tools developed and illustrated can be developed further for use in operational water management predicting the hydrological response due to changes in land use and water demand based on various management schemes. It is advised that the infrastructure developed during this work for collecting further measurements concerning the hydrological elements in the area continues to be operated.
Chen, Mi. "Using an integrated linkage method to predict hydrological responses of a mixed land use watershed." Connect to this title online, 2003. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu.
Full textTitle from first page of PDF file. Document formatted into pages; contains xvi, 378 p.; also includes graphics (some col.). Includes bibliographical references (p. 229-252). Available online via OhioLINK's ETD Center
Jones, Charles Nathaniel. "Floodplain Hydrology and Biogeochemistry." Diss., Virginia Tech, 2015. http://hdl.handle.net/10919/75169.
Full textPh. D.
Rahman, Abdullah Faizur 1963. "Monitoring regional-scale surface hydrologic processes using satellite remote sensing." Diss., The University of Arizona, 1996. http://hdl.handle.net/10150/191212.
Full textLoaiza, Usuga Juan Carlos. "Soil hydrology in the Ribera Salada Catchment (Catalan PrePyrenees): application of hydrologic models for the estimation of hydrologic transitional regimes." Doctoral thesis, Universitat de Lleida, 2007. http://hdl.handle.net/10803/8235.
Full textafectada per canvis d'ús del sòl, mitjançant el monitoreig d'aquest i de l'aigua superficial. Aquest
objectiu s'ha treballat a partir mesuraments de components del balanç hídric pels diferents tipus de
cobertura i sòl, amb règims d'humitat i temperatura de transició.
Aquest estudi s'ha realitzat a la conca de la Ribera Salada (Prepirineu meridional Català, al NE
d'Espanya), amb una extensió de 222.5 km2, i un interval altitudinal de 420 a 2385 m i predomini de
pendents entre 12 - 25 % i 25 - 50 %. El substrat consisteix en conglomerats calcaris massius, calcilutites
i llims. La precipitació es de 507 i 763 mm. Amb sòls poc profunds, calcaris i pedregosos, essent
majoritàriament Inceptisòls (Typic Calciusteps, Typic Haploustepts) i Entisòls (Typic Ustifluvents, Typic
Udorthortents). A les zones més elevades de la conca, els sòls són més humits, degut a l'augment de la
precipitació, on es produeixen processos de descarbonatació del sòl. L'ús del sòl és majoritàriament
forestal, amb presència d'ecosistemes de ribera, subalpins i vegetació submediterrània. Algunes àrees es
troben amb cultius de patata, cereal i pastures. Una de les característiques més importants d'aquesta
conca són els canvis d'ús del sòl que ha patit en els últims 50 anys degut a l'abandó dels masos i cultius
tradicionals. Es seleccionaren vuit llocs de mostreig considerant les següents cobertes: Quercus ilex, bosc
de ribera, Pinus sylvestris, pastures, cultius (cereal-patata) i Pinus uncinata. A partir de l'any 1997 fins el
2005, s'han anat monitorejant el contingut d'humitat del sòl, l'escolament i els cabals. Des del 2004 s'han
anat anotant dades de drenatge. Les variables meteorològiques es mesuren a l'estació de Lladurs de la
XAC (Xarxa Agrometeorològica de Catalunya).
Els resultats obtenguts durant tres anys mostren una domini del règim d'humitat ústic (SSS, 2006), o xèric
en aquells anys més secs. En la modelització de règims d'humitat i temperatura del sòl, s'utilitzaren els
models de simulació NSM "Newhall simulation model" (Newhall, 1976) i JSM "Jarauta simulation
model" (Jarauta 1989). NSM (Newhall,1976) tendeix a sobre estimar el règim d'humitat del sòl, però
JSM (Jarauta, 1989) simula correctament el règim d'humitat del sòl (SSS, 2006) de la conca, funcionant
millor en condicions intermitges d'humitat del sòl. Ambdós models simulen correctament el règim de
temperatura dels sòls. Predomina un règim de temperatura mèsic-tèrmic, amb tendència a tèrmic els anys
secs. A petita escala la profunditat del sòl, pendent, pedregositat i una alta porositat del sòl són factores
que varien el règim d'humitat del sòl. La informació de sòl i clima, complementada mitjançant SIG, va
permetre l'obtenció de mapes de règim d'humitat del sòl de la conca, a escala 1:50000, els quals
permeten establir mediante simució els règims d'humitat del sòl en diferents escenaris de canvis
meteorològics.
El model TOPLATS ha sigut utilitzat en l'estimació de l'humitat del sòl en diferents usos del sòl. Aquest
model fou calibrat amb les equacions del filtre Kalman estès (EKF), que deriven de la minimització del
quadrat de la diferència entre els valors reals i els estimats (Goegebeur & Pauwels, 2007). Aquesta
metodologia interrelaciona correctament els valors de pluja, humitat del sòl, escolament i infiltració,
essent els valors d'humitat els que més s'aproximen als reals. Els resultats mostren que aquest filtre és
una eina útil per estimar el volum d'aigua del sòl emmagatzemada en conques a escala puntual,
assegurant una aplicació correcta del model hidrològic.
Per la modelització del comportament de l'humitat del sòl i diferents components del balanç hídric
s'utilitzà el modelo TOPLATS (Famiglietti & Wood, 1994). El model de simulació TOPLATS permite
simulà acceptablement el comportament de l'humitat del sòl. Els resultats de infiltració, escolament,
intercepció, evapotranspiració de referència i temperatura del sòl són correctes. Les diferències existents
entre valors simulats i observats són: l'humitat del sòl no sobrepassa el 5%, la infiltració fluctua entre 4%
i 15%, la diferència entre els valors reals i simulats d'evapotranspiració, depèn de l'estació de l'any,
essent 1mm a l'hivern i 2.7 mm a l'estiu. La temperatura varia entre 0.01ºC i 3.5ºC. El model calibrat
prediu amb precisió el comportament de les diferents components del balanç hídric. Respecte als valors
mesurats d'aigua de drenatge correspon al 11-41 % de la pluja total.
Respecte al balanç d'aigua en el sòl (ΔSW), els valors són negatius durant cert període de l'any, arribant a
valors crítics els mesos secs. La recuperació de humitat del sòl durant la resta de mesos succeeix de
manera parcial. A la part mitja de la conca, alguns mesos els valors d'humitat del sòl s'acosten a
condicions de punt de marchites (ecosistema submediterrani). A la part alta de la conca el sòl conserva
humitat (ecosistema subalpí). Els valors de cabal trobats corresponen a aportacions per escolament el
cuals són molt baixos. La majoria de les sortides es deuen a evapotranspiració, intercepció, infiltració i
drenatge (en ordre de importància).
El principal objetivo de esta investigación es estudiar la dinámica hidrológica de una cuenca Mediterránea
afectada por los cambios de uso del suelo, mediante el monitoreo del suelo y el agua superficial. Dicho objetivo
se ha abordado a partir de la medición de componentes del balance hídrico para diferentes tipos de cobertura y
suelo, considerando regimenes de humedad y temperatura de transición.
Este estudio se ha realizado en la cuenca de la Ribera Salada (Prepirineo meridional Catalán, NE España) de
222.5 km2, con un intervalo altitudinal de 420 a 2385 m y predominio de pendientes entre 12 - 25 % y 25 - 50
%. El sustrato consiste en conglomerados calcáreos masivos, calcilutitas y limos. La precipitación anual es de
507 y 763 mm. Los suelos són poco profundos, calcáreos y pedregosos, siendo en su mayoría Inceptisols
(Typic Calciusteps, Typic Haploustepts) y Entisols (Typic Ustifluvents, Typic Udorthortents). En las partes
altas de la cuenca los suelos son más húmedos, debido al aumento de la precipitación, allí ocurren procesos de
descarbonatación del suelo. Predomina el uso forestal, con ecosistemas de ribera, subalpinos y vegetación
submediterránea. Algunas áreas se dedican al cultivo de patatas, cereal y pastos. Una de las características más
importantes de esta cuenca es los importantes cambios de uso del suelo sufridos en los últimos 50 años, debido
al abandono de las masías y cultivos tradicionales.
Se seleccionaron ocho sitios de muestreo, considerando las siguientes coberturas: Quercus ilex, bosque de
ribera, Pinus sylvestris, pastos, cultivo (cereal-patata) y Pinus uncinata. A partir del año 1997 hasta 2005, se
han venido monitoreando el contenido de humedad del suelo, escorrentía y caudales. Desde 2004 se vienen
tomando datos drenaje. Las variables meteorológicas se miden la estación Lladurs perteneciente a la XAC
(Xarxa Agrometeorológica de Cataluña).
Los resultados obtenidos par un period de tres años muestran una predominancia del regimen de humedad
ústico (SSS, 2006), o xérico en los años más secos. Se utilizaron los modelos de simulación NSM "Newhall
simulation model" (Newhall, 1976) y JSM "Jarauta simulation model" (Jarauta 1989) en la modelización de
regimenes de humedad y temperatura del suelo. NSM (Newhall,1976) tiende a sobre estimar el régimen de
humedad del suelo. Por contra, JSM (Jarauta, 1989) simula de forma correcta el régimen de humedad del suelo
(SSS, 2006) presente en la cuenca, funcionando mejor bajo condiciones medias de humedad del suelo. Ambos
modelos simulan de forma correcta el régimen de temperatura de los suelos. Predomina un régimen de
temperatura mésico-térmico, con tendencia a térmico para los años secos. A pequeña escala la profundidad del
suelo, pendiente, pedregosidad y alta porosidad del suelo son factores que hacen variar el régimen de humedad
del suelo. La información de suelo y clima, complementada mediante SIG, permitió obtener mapas de régimen
de humedad del suelo para la cuenca, a una escala 1:50000, los cuales permiten establecer mediante simulación
los regimenes de humedad en el suelo bajo diferentes escenarios de cambios meteorológicos.
El modelo TOPLATS ha sido utilizado en la estimación de la humedad en el suelo para diferentes usos del
suelo. Este modelo fue calibrado con las ecuaciones del filtro Kalman extendido (EKF), que se derivan de la
minimización del cuadrado de la diferencia entre los valores reales y los estimados (Goegebeur & Pauwels,
2007). Esta metodología interrelaciona correctamente los valores de lluvia, humedad en el suelo, escorrentía y
infiltración, siendo los valores de humedad los mas ajustados a los valores reales. Los resultados muestran que
este filtro es una herramienta para estimar el volumen de agua en el suelo almacenada en las cuencas a escala
puntual, asegurando una aplicación correcta del modelo hidrológico.
Para la modelización del comportamiento de la humedad del suelo y los diferentes componentes del balance
hídrico se utilizó el modelo TOPLATS (Famiglietti & Wood, 1994). El modelo de simulación TOPLATS
permite simular aceptablemente el comportamiento de la humedad del suelo. Los resultados para infiltración,
escorrentía, intercepción, evapotranspiración de referencia y temperatura del suelo son correctos. Las
diferencias existentes entre valores simulados y observados son: la humedad del suelo no sobrepasa el 5%, la
infiltración fluctúa entre 4% y 15%, la diferencia entre los valores reales y simulados de evapotranspiración,
depende de la estación del año, siendo 1mm en invierno y 2.7 mm en verano, la temperatura varia entre 0.01 ºC
y 3.5ºC. El modelo calibrado predice con precisión el comportamiento de las diferentes componentes del
balance hídrico. Respecto a los valores medidos para agua de drenaje corresponde al 11-41 % de la lluvia total.
Respecto al balance de agua en el suelo (ΔSW), los valores son negativos para un corto periodo del año,
alcanzando valores críticos en meses secos. La recuperación de humedad del suelo para el resto de los meses
ocurre de manera parcial. En la parte media de la cuenca, para algunos meses los valores de humedad del suelo
son cercanos a condiciones de punto de marchites permanente (ecosistema submediterráneo). En la parte alta
de la cuenca el suelo conserva condiciones intermedias de humedad (ecosistema subalpino). Los valores de
caudal encontrados corresponden a los aportes por escorrentía, los cuales son muy bajos. La mayor parte de las
salidas ocurren por evapotranspiración, intercepción, infiltración y drenaje (en orden de importancia).
The main aim of this research is to study the hydrological dynamics of a Mediterranean mountain basin
affected by land use changes, by means of the monitoring of soil and surface water. This aim has been
reached by measuring and simulating hydric balance components of different soils and under different
vegetational types, considering water and temperature transition regimes.
This research was done in Ribera Salada basin (Catalan Pre Pyrenees, NE Spain), with an area of 222.5
km2, altitudes between 420 and 2385 m, with predominance slopes between 12 - 25 % and 25 - 50 %. The
substrate consists of massive calcareous conglomerates, calcilutites and limestones. Main annual
precipitation are 507 to 763 mm. Soils are shallow, calcareous and stony, being most of them Inceptisols
(Typic Calciusteps, Typic Haploustepts) and Entisols (Typic Ustifluvents, Typic Udorthortents). In the
upper and moister part of the basin soil decarbonatation takes place. Forest use is predominant, going
from brook forest environments to subalpine and submediterranean vegetation. Agricultural uses include
mainly the growing of cereals, potatoes and pastures. One of the most important characteristics in this
basin are the significant soil use changes in the last 50 years, due to the abandonment of farms and
traditional crops.
Eight sites were studied, corresponding to soils under Quercus ilex, brook forest, Pinus sylvestris, pasture,
crops (cereal-potatoes) and Pinus uncinata. From 1997 until 2005, soil moisture, run-off, water flow and
interception were monitored. From 2004 on, drainage data has been recorded. Meteorological variables
were measured by means of a complete Lladurs meteorological station, belonging to XAC (Catalan
Agrometeorological Network).
The obtained results to three years show the predominance of ustic moisture regime (SSS, 2006), or xeric
during the driest years. The simulation models NSM "Newhall simulation model" (Newhall, 1976) and
JSM "Jarauta simulation model" (Jarauta 1989) were used to represent soil moisture and temperature
regimes. NSM estimates a higher level of soil moisture regimes than observed. On the contrary, JSM
simulates correctly soil moisture regimes, working better under intermediate soil moisture conditions.
Both models simulate correctly the soil temperature regimes, being mesic-thermic to thermic during the
driest years. At detailed scale (plot observation), soil depth, slope, stone amount and high soil porosity are
factors that affect the soil moisture regimes. Soil and climate information, implemented through a GIS,
allowed us to obtain soil moisture regime maps of the basin at a 1:50000 scale, which are very useful to
simulate soil moisture regimes in different scenarios of meteorological changes.
The TOPLATS model, when used to estimate soil moisture under different cover types, was calibrated
with Extend Kalman filter (EKF) equations derived through a minimization of the square difference
between the true and estimated model state (Goegebeur & Pauwels, 2007). This methodology interrelates
correctly rainfall, soil moisture, runoff and infiltration. Among them, the obtained soil moisture values
corresponded the best to observed data. The results show that it is a useful tool to estimate soil water
volume stored in basins at a point scale, ensuring a correct application of this hydrological model.
To model soil moisture behaviour and the different hydric balance components, the TOPLATS model
(Famiglietti & Wood, 1994) was used. TOPLATS model simulates correctly the soil moisture behaviour.
The differences between observed and simulated values are the following: soil moisture does not surpass
5%; the infiltration fluctuates between 4% to 15%; in evapotraspiration depends on the season being
between 1 mm in winter to 2.7 mm in summer, soil temperature values difference fluctuates between
0.01ºC and 3.5ºC.The calibrated model predicts precisely the behaviour of different hydric balance
components. The measured water drainage amount is 11-41 % of total rain.
The observed and simulated soil water storage in the basin (ΔSW), has negative values during the driest
months. Soil moisture recovery during the rest of the months is only partial. In the medium part of the
basin, occupied by submediterranean ecosystems, soil moisture values are closer to drought conditions
during some months of the year. In the highest part of the basin (subalpine ecosystems) there are
intermediate soil moisture conditions in dry periods. Most part of water outputs are due to
evapotranspiration, interception, infiltration and drainage, in decreasing order of importance. Run-off
values are very low.
Peacock, Catherine. "Reedbed hydrology and water requirements." Thesis, Cranfield University, 2003. http://dspace.lib.cranfield.ac.uk/handle/1826/3836.
Full textNuttle, William Kensett. "Elements of salt marsh hydrology." Thesis, Massachusetts Institute of Technology, 1986. http://hdl.handle.net/1721.1/14991.
Full textMICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING
Includes bibliographies.
by William Kensett Nuttle.
Ph.D.
Mandilaris, Konstantinos. "An Empirical Study on Socio-Hydrology and the HistoricalEvolution of Flood Riskin Pori, Finland." Thesis, Uppsala universitet, Institutionen för geovetenskaper, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-303605.
Full textUrbaniseringen växer fortlöpande över hela världen. Både industriländer och utvecklingsländer befrämjar snabb expansion för ökad tillväxt och produktion. Dock leder urbanisering i kombination med klimatförändring till högre risk för extrema översvämningar. Människor har i alla tider bosatt sig runt vattendrag och flodslätter som naturligt är mer benägna att översvämmas, något som gör att dagvattenhantering och stadsplanering är absolut nödvändigt för ökad säkerhet och reducerad översvämningsrisk.Fram tills nu har många viktiga studier genomförts som behandlar farorna för människor bosatta i urbaniserade städer intill flodslätter, men de flesta av dem har utgått från utvecklingsländer som Bangladesh eller Vietnam, något som lett till en märkbar avsaknad av information gällande industri-länder. Gemensamt för dessa studier är dock att de ignorerar den ständigt föränderliga mänskliga faktorn och på så sätt inte tar i beaktning interaktioner mellan vatten och samhälle.Socio-hydrologi är en ny gren inom hydrologi som är nära besläktad med Integrerad Vattenresurs-förvaltning och som försöker utforska detta dynamiska samspel. Denna studie undersöker den historiska utvecklingen av en starkt urbaniserad industristad i Finland och försöker tolka de mänskliga och tekniska effekterna av urbanisering. Staden Pori (Björneborg på svenska) är den mest översvämningsbenägna platsen i Finland, vilket gör denna studie till ett viktigt arbete för att ta fram betydelsefulla resultat och eventuella rekommendationer för framtida forskning. Dessutom inkorporeras socio-hydrologi, den mänskliga faktorn och översvämningsrisk för första gången i forskning gällande en större europeisk stad.Detta är ett empiriskt projekt med data insamlat från olika källor som sammanställts för första gången och som kan förändra både invånares och forskares synsätt, samt vara en grund för mer utförlig och modellbaserad forskning i framtiden. Frågan som denna avhandling försöker besvara är hur socio-hydrologisk dynamik har påverkat förändringar av översvämningsrisker i staden Pori i Finland över de senaste årtiondena.
Wang, Ying. "Uncertainty analysis of geomorphologic instantaneous unit hydrograph for hydrosystems reliability evaluation /." View abstract or full-text, 2005. http://library.ust.hk/cgi/db/thesis.pl?CIVL%202005%20WANG.
Full textMiller, Scott N. "Scale effects of geometric complexity, misclassification error and land cover change in distributed hydrologic modeling." Diss., The University of Arizona, 2002. http://etd.library.arizona.edu/etd/GetFileServlet?file=file:///data1/pdf/etd/azu_e9791_2002_216_sip1_w.pdf&type=application/pdf.
Full textFurman, Alexander. "Steps towards the implementation of ERT for monitoring of transient hydrological processes." Diss., The University of Arizona, 2003. http://etd.library.arizona.edu/etd/GetFileServlet?file=file:///data1/pdf/etd/azu_e9791_2003_271_sip1_w.pdf&type=application/pdf.
Full textKim, Taewook. "GSFLOW Modeling of the Souhegan River watershed, New Hampshire, USA." The Ohio State University, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=osu1418723314.
Full textShastry, Apoorva Ramesh. "Improving Topography Data for Flood Modeling: A Case Study in the Logone Floodplain." The Ohio State University, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=osu1562951935792606.
Full textWesterberg, Ida. "Utveckling och tillämpning av en GIS-baserad hydrologisk modell." Thesis, Uppsala University, Department of Earth Sciences, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-88880.
Full textA distributed hydrological rainfall-runoff model has been developed using a GIS integrated with a dynamic programming module (PCRaster). The model has been developed within the framework of the EU-project TWINBAS at IVL Swedish Environmental Research Institute, and is intended for use in WATSHMAN – a tool for watershed management developed at IVL. The model simulates runoff from a catchment based on daily mean values of temperature and precipitation. The GIS input data consist of maps with soil type, land-use, lakes, rivers and a digital elevation model. The model is a hybrid between a conceptual and a physical model. The snow routine uses the degree-day method, the evapotranspiration routine uses the Blainey-Criddle equation, the infiltration routine is based on Green-Ampt, groundwater is modelled assuming a linear reservoir and the flow routing is done with the kinematic wave equation combined with Manning’s equation.
The GIS and the hydrologic model are embedded in one another, allowing calculation of each parameter in each grid cell. The output from the model consists of raster maps for each time step for a pre-defined parameter, or a time series for a parameter at a specified grid cell. The flow network is generated from the digital elevation model and determines the water flow on the grid scale. The smallest possible grid size is thus obtained from the resolution of the digital elevation model. In this implementation the grid size was 50 m x 50 m. The raster structure of the model allows for easy use of data from climate models or remotely sensed data.
The model was evaluated using the River Kölstaån catchment, a part (110 km2) of the Lake Mälaren catchment, which has its outflow in central Stockholm, Sweden. The integration of the GIS and the hydrologic model worked well, giving significant advantages with respect to taking lakes and land-use into account. The evaluation data consisted of observed run-off for the period 1981 to 1991. The result from the calibration period shows a great variation in Reff (Nash & Sutcliffe) between the years, the three best years having Reff-values of 0.70 – 0.80. The Reff-value for the entire calibration period was 0.55 and 0.48 for the validation period, where again there was great variation between different years. The volume error was 0.1 % for the calibration period and -21 % for the validation period. The evapotranspiration was overestimated during the validation period, which is probably a result of excess rain during the calibration period. The results are promising and the model has many advantages – especially the integrated GIS-system – compared to the present WATSHMAN model. It could be further developed by introducing a second groundwater storage and refining the evapotranspiration and infiltration routine. Given the promising results, the model should be evaluated in other larger and hillier areas and preferably against more distributed data.
En helt distribuerad GIS-baserad hydrologisk modell för modellering i avrinningsområden på lokal/regional skala har byggts upp i PCRaster. Arbetet utfördes på IVL Svenska Miljöinstitutet AB inom ramen för EU-projektet TWINBAS, som har som mål att identifiera kunskapsluckor inför implementeringen av EU:s ramdirektiv för vatten. Modellen är tänkt att användas i WATSHMAN (Watershed Management System), IVLs verktyg för vattenplanering i avrinningsområden där bland annat källfördelningsberäkningar och åtgärdsanalyser ingår. Den uppbyggda modellen är en hybrid mellan en fysikalisk och en konceptuell hydrologisk modell och predikterar vattenföring på pixelnivå i avrinningsområden. Simuleringen drivs av dygnsmedelvärden för temperatur och nederbörd och modellen tar hänsyn till markanvändning, jordart, topografi och sjöar. De modellekvationer som används är grad-dagsmetoden för snö, Blainey-Criddle för evapotranspiration, Green-Ampt för infiltration, linjärt magasin för grundvatten och Mannings ekvation för flödesrouting.
Det geografiska informationssystemet och den hydrologiska modellen är helt integrerade, vilket gör att alla parametervärden beräknas för varje enskild pixel. Som utdata ger modellen en rasterkarta för varje tidssteg för en i förväg bestämd parameter, eller tidsserier över parametervärden i definierade punkter. Vattnet transporteras i ett utifrån höjdmodellen genererat flödesnätverk och vattnets flödesväg bestäms därmed på pixelnivå. Minsta möjliga pixelstorlek bestäms således utifrån höjdmodellens upplösning, och var vid denna tillämpning 50 m gånger 50 m. Modellens uppbyggnad med raster gör det enkelt att använda data från klimatmodeller eller fjärranalys.
Avrinningsområdet för Kölstaån, ett biflöde till Köpingsån i Mälardalen, har använts för att utvärdera modellen. Integreringen av GIS och hydrologisk modell fungerade mycket väl och gav stora fördelar t ex vad gäller att ta hänsyn till sjöar och markanvändning. Modellen kalibrerades med data från åren 1981 till 1986 och det erhållna volymfelet var då 0,1 % och Reff-värdet (Nash & Sutcliffe) 0,55. Stora variationer erhölls dock mellan åren; för de tre bästa åren låg Reff-värdet mellan 0,70 och 0,80. Ett mycket kraftigt nederbördstillfälle samt regleringar i huvudfåran av vattendraget ligger troligtvis bakom de mindre väl beskrivna åren. Även under valideringsperioden (1987 till 1991) fungerade modellen väl, så när som på att avdunstningen överskattades på vårarna (antagligen beroende av det stora regnet under kalibreringen), och Reff-värde och volymfel hamnade på 0,48 respektive -21 %, även här med stora variationer mellan åren. Resultaten är lovande och modellen har många fördelar jämfört med den nuvarande WATSHMAN-modellen. Den skulle kunna förbättras ytterligare genom att dela upp grundvattnet i två magasin samt förfina evapotranspirations- och infiltrationsrutinerna. Den höjdmodellsbaserade modellen bör utvärderas även i andra mer kuperade områden samt mot mer distibuerade data.
Guay, Bradley Evan. "Preliminary Hydrologic Investigation of Topock Marsh, Arizona 1995-98." Diss., The University of Arizona, 2001. http://etd.library.arizona.edu/etd/GetFileServlet?file=file:///data1/pdf/etd/azu_e9791_2001_265_sip1_w.pdf&type=application/pdf.
Full textPage 189 missing in original volume. There are two pages numbered 190. Includes bibliographical references (leaves 329-334).
Smith, Katie A. "Investigating uncertainty in global hydrology modelling." Thesis, University of Nottingham, 2016. http://eprints.nottingham.ac.uk/31875/.
Full textTilford, Kevin A. "Weather radar data for operational hydrology." Thesis, University of Salford, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.315383.
Full textCloke, Hannah Louise. "Modelling riparian hydrology and streamflow generation." Thesis, University of Bristol, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.288231.
Full textGavin, Helen. "Wetland hydrology of the Elmley marshes." Thesis, University College London (University of London), 2001. http://discovery.ucl.ac.uk/1349893/.
Full textFyffe, Catriona Louise. "The hydrology of debris-covered glaciers." Thesis, University of Dundee, 2012. https://discovery.dundee.ac.uk/en/studentTheses/1ff21418-34ba-4e0a-97ed-69510f3b882c.
Full textGanesan, Maya. "A circular model of urban hydrology." Thesis, This resource online, 1996. http://scholar.lib.vt.edu/theses/available/etd-09182008-063254/.
Full textVander, Jagt Benjamin J. "On the characterization of subpixel effects for passive microwave remote sensing of snow in montane environments." The Ohio State University, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=osu1449233895.
Full textBlake, James Richard. "Modelling the dynamic interaction between hillslope hydrology and retaining structures (hydrology and retaining wall stability model: HYDRET)." Thesis, University of Bristol, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.402319.
Full textWigmore, Oliver Henry Wigmore. "Assessing Spatiotemporal Variability in Glacial Watershed Hydrology: Integrating Unmanned Aerial Vehicles and Field Hydrology, Cordillera Blanca, Peru." The Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu1471854919.
Full textMartínez, Fabián. "Modeling the Interactions between Hydrological Extremes, Water Management and Society." Thesis, Uppsala universitet, Institutionen för geovetenskaper, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-296414.
Full textGenom historien har det funnits en nära relation mellan hydrologiska och sociala processer. De flesta tidiga civilisationer runt om i världen utvecklades tack vare tillgången till floder och deras vattenresurser. Traditionella hydrologiska metoder har emellertid inte lyckats fånga denna observerade interaktion och har alltför länge ignorerat de mänskligt drivna effekterna i det hydrologiska systemet och hur de i sin tur formar de hydrologiska förhållandena som ofta observerats. Denna forskning har utvecklat en ny konceptuell modell med avsikt att fånga tvåvägsinteraktionen mellan samhällen och deras respons under extrema hydrologiska händelser, både översvämningar och torka. Denna konceptualisering baseras på observationen att samhällen ackumulerar minne (ökar medvetenheten) efter en extrem händelse. Baserat på ansamling av samhällets minne fattar det mänskliga systemet (samhällen) beslut över vattenhushållning, vilket påverkar det hydrologiska systemet (floder). När inga extrema hydrologiska händelser registreras, avklingar samhällsminnet med en viss hastighet och sedan fattas nya beslut om vattenhushållningen i det hydrologiska systemet. Den konceptuella modellen har tillämpats på Brisbaneflodens avrinningsområde, i Australien, med anledning av den extrema torka och stora översvämningar som observerats under de tre senaste decennierna. Resultaten tyder på att den enkla föreslagna konceptuella modellen kan fånga samspelet mellan människa och hydrologiska system. Dessutom visar den att ett samhälles minne är drivkraften för det mänskliga systemet och är den främsta orsaken till att samhällen gör inverkan på de naturliga förhållandena i avrinningsområdet. Samtidigt visar konceptualiseringen att denna typ av vattenförvaltning, som baseras på samhällsminnet, faktiskt kan förstärka de potentiella skador som kan uppkomma i samband med extrema hydrologiska händelser. Slutligen framhåller utvecklingen av denna nya metod det stora behov som finns för att förbättra förståelsen av samspelet mellan de hydrologiska och sociala processerna.
Keel, Brian Jennings. "The effect of dataset quality and resolution on the application of the land surface hydrologic model TOPLATS to the middle swamp watershed." Thesis, Georgia Institute of Technology, 2001. http://hdl.handle.net/1853/20815.
Full textLiu, Ganming. "Hydrologic Response of Surface Waters in the Prairie Pothole Region to Climate Variability." The Ohio State University, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=osu1313170630.
Full textTuozzolo, Stephen. "A study of river discharge estimation methods for the forthcoming Surface Water and Ocean Topography (SWOT) mission." The Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu154150483606865.
Full textCulbertson, Andreas Mitsutoshi. "Effects of climate change on Maumee River basin hydrology and nutrient runoff." The Ohio State University, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=osu1437226063.
Full textCallahan, Michael Kroh. "Groundwater Controls on Physical and Chemical Processes in Streamside Wetlands and Headwater Streams in the Kenai Peninsula, Alaska." Scholar Commons, 2014. https://scholarcommons.usf.edu/etd/5347.
Full textFlowers, Gwenn Elizabeth. "A multicomponent coupled model of glacier hydrology." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/nq61088.pdf.
Full textSeibert, Jan, S. Uhlenbrook, and T. Wagener. ""Hydrology education in a changing world" Preface." Uppsala universitet, Luft-, vatten och landskapslära, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-201950.
Full textDickson, Andrew. "The hydrology of landfill and land management." Thesis, University of Strathclyde, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.324894.
Full textRebelo, Mariana da Silva. "Portuguese georesources suitability for medical hydrology applications." Doctoral thesis, Universidade de Aveiro, 2011. http://hdl.handle.net/10773/7869.
Full textIn Portugal, there is an old tradition in using clayey materials for therapeutic purposes. They are applied in pelotherapy, at several beaches of the Atlantic coast in the form of clay-sea water mixtures (peloids) to treat skin and rheumatic diseases. During many generations, peloids have been applied without scienti c studies that prove their therapeutic validity. In the last decade, the Portuguese scienti c community has become increasingly more interested in assessing the properties that make clayey materials suitable for therapeutic purposes. The abundance of clayey formations and the established practices of medical hydrology in our country turned this interest into a new perspective of application. The studied materials include di erent clays (in age and origin) mainly collected from well-known Mesozoic-Cenozoic formations, in some cases outcropping at beaches where empirical applications occur. This thesis focus in the study of silt-clay fraction (< 63 m).To determine their suitability for therapy, compositional, physicochemical, technological, thermal and rheological properties were assessed. Conventional techniques (XRD, XRF and Sedigraph) were used to assess compositional features of silt-clay fraction. Electron microscopy (SEM, VPSEM, HREM) was used to study the micromorphology and composition of clay fraction (< 2 m). Physicochemical properties (cation exchange and speci c surface) were assessed using the Ammonium Acetate and BET methods. Technological properties (plasticity and abrasivity indices) were assessed using the Atterberg limits and Einlehner abrasion tests. Thermal properties (speci c heat and cooling kinetics) were estimated by DSC analysis and cooling tests. Pharmacotechnical tests (compressibility index, sediment volume and Brook eld viscosity) were used to assess the powder owability as well as the physical stability and viscosity of clay-water dispersions. We selected as suitable Portuguese clays for health applications the samples A-Pe, A-Be2, A-Sd, J-Fr , M-To, C-Lu1, C-Lu2, Pl-Ba, M-Ga and J-Ab because they represent safe materials, with an adequate composition, good technological, physicochemical and thermal properties for application, also presenting an adequate rheology when dispersed in water. Their most relevant characteristics are the high clay minerals content, abundant smectite, illite and kaolinite, and safe hazardous concentrations. They also showed moderate capacity to exchange Ca 2+, high plasticity, low abrasivity, high speci c heat and slow cooling kinetics. They evidenced fair powder owability and good potential to formulate viscous dispersions when stabilized. Because the majority of the assessed characteristics are in accordance with those presented by clays applied in European spas for pelotherapy, we considered this group of clays also suitable for medical hydrology treatments in Portuguese spas.
Em Portugal, o uso de materiais argilosos para fins terapêuticos é uma prática que persiste desde a antiguidade. A aplicação (peloterapia) é realizada em algumas praias do litoral Atlântico sob a forma de pastas de argila misturada com água do mar (pelóide). Ao longo de várias gerações os pelóides têm sido utilizados para tratar doenças dermatológicas e reumáticas sem estudos científicos que comprovem a sua validade terapêutica. Na última década, a comunidade científica Portuguesa tem vindo a interessar-se cada vez mais pela avaliação das propriedades que tornam os materiais argilosos adequados para peloterapia. A abundância de formações argilosas e as práticas de hidrologia médica reconhecidas no nosso pais transformaram este interesse numa nova perspectiva de aplicação. Para este estudo, foram amostradas diferentes argilas (em idade e origem) provenientes sobretudo de formações Mesozóicas-Cenozóicas bem conhecidas. Algumas destas formações a oram em praias onde a aplicação tradicional de argila ocorre. Esta tese foca-se no estudo da fracção silto-argilosa (< 63 m) dos materiais amostrados. A avaliação das suas propriedades composicionais, físico-químicas, tecnológicas, térmicas e reológicas permitiu estimar a sua aplicabilidade terapêutica. Técnicas convencionais (DRX, FRX, Sedigraph) foram utilizadas para estudar a composição da fracção silto-argilosa. A microscopia electrónica (SEM, VPSEM e HREM) permitiu estudar a micromorfologia e a composi ção da fracção argilosa (< 2 m). As propriedades físico-químicas (troca catiónica, superfície específica) foram determinadas pelos métodos do Acetato de Amónio e BET. As propriedades tecnológicas (plasticidade e abrasividade) foram avaliadas utilizando os limites de Atterberg e teste de abrasão de Einlehner. As propriedades térmicas foram determinadas recorrendo á análise térmica calorimétrica (DSC) e cinética de arrefecimento. Ensaios de tecnologia farmacêutica (compressibilidade, volume de sedimento e viscosidade de Brook eld) foram utilizados para o estudo da uidez de pós assim como da estabilidade física e viscosidade das dispersões argila-água. Foram seleccionadas como argilas Portuguesas com aplicabilidade em saúde as amostras A-Pe, A-Be2, A-Sd, J-Fr , M-To, C-Lu1, C-Lu2, Pl-Ba, M-Ga and J-Ab por serem materiais seguros e de composição adequada, com propriedades físico-químicas, tecnológicas e térmicas benéficas para aplicação. Estas argilas apresentam igualmente uma reologia apropriada quando dispersas em água. As suas características mais relevantes são o elevado conteúdo em minerais de argila, abundância de esmectite, ilite e/ou caulinite e a toxicidade aceitável. Apresentam uma capacidade razoável para trocar catiões, destacando-se o Ca 2+, assim como elevada plasticidade, baixa abrasividade, elevado calor específico e cinética de arrefecimento lenta. Por fim, evidenciaram uma uidez de pó razoável e capacidade para originar dispersões viscosas quando estabilizadas. Uma vez que a maioria das características avaliadas nas argilas Portuguesas estão de acordo com aquelas aplicadas nos spas Europeus para peloterapia, consideramos este grupo de argilas aplicável para tratamentos de hidrologia médica nos spas Portugueses.
Ffolliott, Peter F., Leonard F. DeBano, Lori A. Strazdas, Malchus B. Jr Baker, and Gerald J. Gottfried. "Hydrology and Water Resources: A Changing Emphasis?" Arizona-Nevada Academy of Science, 1997. http://hdl.handle.net/10150/296488.
Full textFfolliott, Peter F., Daniel G. Neary, and Gerald J. Gottfried. "A Brief History of the Hydrology Section." Arizona-Nevada Academy of Science, 2006. http://hdl.handle.net/10150/296616.
Full textSartore, Luca. "Quantile Regression and Bass Models in Hydrology." Doctoral thesis, Università degli studi di Padova, 2014. http://hdl.handle.net/11577/3423658.
Full textI fenomeni spazio-temporali relativi alle misurazioni di piovosità possono essere caratterizzati da modelli statistici fondati su concetti fisici invece di essere identificati da modelli standard basati su correlazioni spazio-temporali e i relativi strumenti analitici. Questa prospettiva è utile per capire se i rapporti tra zone confinanti e anni consecutivi sono attribuibili a meccanismi fisici latenti. Dati satellitari vengono utilizzati per esaminare questa teoria e fornire prove su base empirica. Una recente teoria idrologica, basata sul concetto di auto-organizzazione, è caratterizzata da meccanismi fisici semplificati che sono essenziali per la spiegazione delle relazioni locali presenti nei dati osservati. I modelli di regressione, che si ispirano alla teoria della diffusione di innovazioni, sono in grado di approssimare l'evoluzione del processo di precipitazione di un singolo anno attraverso una più semplice prospettiva. Tuttavia, la moltitudine di informazioni raccolte richiede tecniche innovative di gestione dei dati e soluzioni analitiche avanzate con lo scopo di ottenere risultati ottimali in tempi ragionevoli. Infatti, i minimi quadrati e la regressione quantilica per modelli non-lineari vengono utilizzati per fare inferenza sulla variabile risposta condizionatamente ad alcune covariate. Una nuova tecnica di regressione quantilica è stata sviluppata ad hoc al fine di fornire stime simultanee che non vìolino la proprietà di monotonicità dei quantili. I minimi quadrati non lineari evidenziano un forte legame tra le precipitazioni e alcune caratteristiche salienti delle zone di misurazione. Inoltre, le analisi ottenute tramite la regressione quantilica quantificano la variabilità intrinseca nei dati.
Zanon, Francesco. "Radar Hydrology and Flash Flood Event Analysis." Doctoral thesis, Università degli studi di Padova, 2010. http://hdl.handle.net/11577/3427349.
Full textUna piena improvvisa è una piena che segue l’evento precipitativo che la ha causata entro un breve periodo di tempo. Il termine “improvvisa o flash” riflette una risposta rapida, con il picco di piena che si verifica nella rete di drenaggio nel volgere di alcuni minuti fino a poche ore dopo l’inizio dell’evento di pioggia. Questo fatto lascia intendere quanto poco tempo ci sia per l’allerta [Creutin and Borga, 2003; Borga et al., 2008]. Questo tipo di bacini rispondo rapidamente ad una precipitazione intensa a causa di pendii ripidi e superfici impermeabili, terreni saturi, o a per fattori determinati dall’uomo (vedi per esempio l’urbanizzazione) o a causa di alterazioni del drenaggio naturale del terreno dovuto ad incendi. Gli eventi scatenanti le piene improvvise sono generalmente precipitazioni che portano all’eccesso di drenaggio, ma questo tipo di piene possono anche essere scatenate dal rilascio improvviso di acqua trattenuta da impedimenti naturali (per esempio formati da ghiaccio e roccia, fango e detriti di legno) o di tipo artificiale come dighe e argini. Questa tesi si concentra su eventi di piena improvvisa associati a precipitazioni intense. L’Europa ha conosciuto diverse inondazioni catastrofiche negli ultimi decenni. I dati relativi un certo numero di queste inondazioni che si sono verificate nel corso degli ultimi 15 anni sono riportati da Marchi et al. (2010). Dall’analisi di questi dati e di queste fonti risulta che: Una piena improvvisa si può verificare in qualsivoglia regione idroclimatica dell’Europa, anche se tre regioni sembrano essere caratterizzate da una grande incidenza di di piene improvvise: l’area Mediterranea, quella Alpino-Mediterranea, e quella Continentale; Una gran quantità di pioggia accumulata è una condizione necessaria ma non sufficiente al verificarsi di una piena improvvisa, dal momento che l’idrologia controlla in modo decisivo l’innesco della piena improvvisa. Senza un’analisi di tipo idrologico, risulta impossibile valutare la probabilità che una data precipitazione scateni una piena, in praticolare in termini di una soglia oltre la quale si verifica la piena; La pericolosià delle piene improvvise è collegata sia alla risposta del fiume (la piena) che alla risposta del terreno (fenomeni di tipo franoso ed erosivo). L’intensa erosione ed il trasporto solido associati a questi fenomeni estremi si aggiungono alla pericolosità ed influenzano in modo significativo la qualità dei terreni, delle acque e degli ecosistemi. La duplice conseguenza delle osservazioni appena fatte è che la previsione di piene improvvise: Dipende in modo determinante dalle previsioni delle precipitazioni che si sviluppano alla meso-scala, con una attenzione specifica ai processi che frenano la circolazione del sistema di precipitazione; Richiedone modelli idrologici che lavorino in tempo reale, con una particolare attenzione ai processi du generazione del deflusso a vasta scala. Anche se raramente sono tutti utilizzati contemporaneamente, i requisiti tecnici per un sistema di previsione idrometeorologica per le piene improvvise comprendono: Un modello numerico di previsione (NWP2), in grado di fornire previsioni quantitative di pioggia a corto raggio (QPF3); Un sistema di rilevamento in remoto per la pioggia (radar, satellite), per il monitoriraggio dei fenomeni temporaleschi e la possibilie inizializzazione e condizionamento del modello NWP, e Un modello di previsione idrologico-idraulico, in grado di prevedere la risposta del corso d’acqua all’input pioggia. Tali requisiti sono simili a quelli più comuni utilizzati per la previsione delle alluvioni dei sistemi fluviali. Tuttavia, alcuni elementi caratterizzano la previsione delle piene improvvise rispetto alla previsione delle alluvioni e ne sottolineano la grande incertezza. Questi sono: Il breve periodo durante il quale questi processi si sviluppano, che implica sia l’integrazione di un sistema di previsione di tipo meteorologico e idrologico, che la difficoltà nell’utilizzo di procedure di assimilazione di dati basate sull’osservazione in tempo reale delle portate al fine di ridurre l’incertezza nelle previsioni idrologiche; La necessità di fornire previsioni a scala locale, il che significa da una parte che la pioggia deve essere monitorata e prevista su una vasta scala spazio-temporale, all’altra che ciascun tributario del bacino monitorato può essere considerato come un bersaglio potenziale per un allarme di piena. La stima di fenomeni precipitativi estremi tramite l’utilizzo del radar meteorologico alla appropriata scala spazio-temporale è una pietra miliare dell’analisi e della previsione delle piene improvvise. Una grande branca della ricerca in questo campo ha favorito un notevolmente migliorato, negli ultimi due decenni, delle tecnologie radar e degli algoritmi per la stima di pioggia. Questo lavoro ha dimostrato che anche utilizzando sistemi radar convenzionali si possono ottenere stime di precipitaziona a livello del suolo, a condizione che vengono adottate una serie di precauzioni, in particolare: L’ubicazione dello strumento e del suo protocollo di scansione devono essere attentamente selezionati ed analizzati; La qualità dello strumento deve essere sottoposta a controlli ordinari; L’elaborazione del segnale deve tener conto della fisica dello strumento così come delle proprietà atmosferiche e dei bersagli di terra. Un controllo a valle del trattamento delle precipitazioni radar può essere fatto tramite misurazioni da pluviometro a livello del suolo utilizzando una varietà di metodi. Quando si sono prese queste precauzioni, diversi studi hanno dimostrato che le stime di precipitazione basate su radar meteorologico sono affidabili e possono essere utilizzate come input di modelli afflussodeflusso per la modellazione e la previsione delle piene [Borga et al., 2000; Delrieu et al., 2005; Borga et al., 2002]. A fronte di questi risultati molto positivi non devono però essere nascosti alcuni punti deboli: La maggior parte di questi risultati non hanno mai la possibilità di essere coerentemente convalidati su un numero significativo di eventi di piena improvvisa. L’utilizzo di esperimenti specifici o di una banca dati limitata di dati radar è insufficiente a testare la combinazione complessa degli algoritmi utilizzati, specialmente se si è interessati ad intensità di pioggia elevata. Un numero molto limitato di risultati positivi è stato tradotto in applicazioni idrologiche operative. Questa tesi si propone di esaminare l’uso del radar meteorologico ai fini della comprensione dei meccanismi idrometeorologici che portano alla formazione di piene improvvise, e quindi alla loro previsione. L’organizzazione del lavoro di tesi è la seguente. Il Capitolo 1 fornisce una revisione della letteratura sul tema della stima di precipitazione tramite radar meteorologico per le precipitazioni che causano la formazione di piene improvvise. Il Capitolo 2 descrive una serie di procedure per la stima delle precipitazioni al suolo durante gli eventi di piena improvvisa in bacini montani. Una metrica per l’analisi spaziale del campo di pioggia viene proposta nel Capitolo 3, nel contesto dell’analisi di una serie di piene improvvise verificatesi in Romania. Questa metrica è utilizzata per l’analisi di due eventi di piena, accaduti rispettivamente nel 2003 nelle Alpi Italiane friulane e nella parte ovest della Slovenia (Capitolo 5). Le conclusioni principali del lavoro di tesi sono riportate nel Capitolo 6.
Wetterhall, Fredrik. "Statistical Downscaling of Precipitation from Large-scale Atmospheric Circulation : Comparison of Methods and Climate Regions." Doctoral thesis, Uppsala University, Department of Earth Sciences, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-5937.
Full textA global climate change may have large impacts on water resources on regional and global scales. General circulation models (GCMs) are the most used tools to evaluate climate-change scenarios on a global scale. They are, however, insufficiently describing the effects at the local scale. This thesis evaluates different approaches of statistical downscaling of precipitation from large-scale circulation variables, both concerning the method performance and the optimum choice of predictor variables.
The analogue downscaling method (AM) was found to work well as “benchmark” method in comparison to more complicated methods. AM was implemented using principal component analysis (PCA) and Teweles-Wobus Scores (TWS). Statistical properties of daily and monthly precipitation on a catchment in south-central Sweden, as well as daily precipitation in three catchments in China were acceptably downscaled.
A regression method conditioning a weather generator (SDSM) as well as a fuzzy-rule based circulation-pattern classification method conditioning a stochastical precipitation model (MOFRBC) gave good results when applied on Swedish and Chinese catchments. Statistical downscaling with MOFRBC from GMC (HADAM3P) output improved the statistical properties as well as the intra-annual variation of precipitation.
The studies show that temporal and areal settings of the predictor are important factors concerning the success of precipitation modelling. The MOFRCB and SDSM are generally performing better than the AM, and the best choice of method is depending on the purpose of the study. MOFRBC applied on output from a GCM future scenario indicates that the large-scale circulation will not be significantly affected. Adding humidity flux as predictor indicated an increased intensity both in extreme events and daily amounts in central and northern Sweden.
Frei, Sven [Verfasser], and Jan H. [Akademischer Betreuer] Fleckenstein. "Interactions between hydrology and biogeochemistry within riparian wetlands : Riparian wetlands: hydrology meets biogeochemistry / Sven Frei. Betreuer: Jan H. Fleckenstein." Bayreuth : Universität Bayreuth, 2013. http://d-nb.info/1059353334/34.
Full textBlasko, Cole. "Assessing hydrologic impacts of the 2013 Rim Fire on the Tuolumne River Watershed in Central Valley, California." Bowling Green State University / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1586445449253322.
Full textSharma, Maneesh. "Assessing effect of resolution and rainfall at plot and watershed scales in hydrologic modeling." Laramie, Wyo. : University of Wyoming, 2007. http://proquest.umi.com/pqdweb?did=1402172481&sid=1&Fmt=2&clientId=18949&RQT=309&VName=PQD.
Full textCarrillo, Soto Gustavo Adolfo. "Catchment Similarity of Hydrologic Partitioning Along Climate Gradients." Diss., The University of Arizona, 2012. http://hdl.handle.net/10150/242371.
Full textThorslund, Josefin. "Hydrological spreading of metal pollution and wetlands as nature-based solutions." Doctoral thesis, Stockholms universitet, Institutionen för naturgeografi, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-147613.
Full textKvaliteten på jordens vattenresurser har försämrats på grund av mänsklig påverkan. En viktig vetenskaplig utmaning är att förstå, kvantifiera och förutsäga den vattenburna spridningen av föroreningar, på skalor som är relevanta för vattenresursförvaltning och åtgärdsprogram. De underliggande, naturliga processer som styr storskalig hydrologisk föroreningstransport kan dock maskeras av att de flesta stora floders flöden är reglerade med hjälp av dammar och reservoarer. Målet med den här avhandlingen är att öka kunskapen kring hydrologisk storskalig spridning av metaller. Detta görs genom att studera nettoeffekter av gruvverksamhet (en viktig källa till globala metallföroreningar) på metallers spridning i vattensystemet, samt att undersöka våtmarkers möjligheter att rena förorenade flöden i landskapet. Avhandlingens huvudstudieområde är Bajkalsjön och dess tillrinningsområde (i Ryssland och Mongoliet), vilket inkluderar den oreglerade Selengafloden och dess delta-våtmarksområden. Även en grupp av globala våtmarksområden har studerats. Flera metoder användes i de fyra studierna som ingår i denna avhandling, inklusive fältmätningar, datasyntes, massflödes- och flödesvägskvantifieringar, och geokemisk modellering. Resultaten visar att gruvdrift i uppströms-delar av Bajkalsjöns tillrinningsområde bidrar betydligt till förhöjda halter av flera metaller i flodsystemen. Massflödenena ökade en storleksordning över gruvområdet. Den observerade metall-specieringen mellan lösta (mer biotillgängliga) och partikulära (mindre biotillgängliga) faser kunde modelleras väl för vissa metaller (Fe, V, Pb och Zn) med en geokemisk jämviktsmodell. Modellen lyckades dock inte reproducera specieringen av andra metaller (Cr, Cu, Mn och Mo). I dessa fall kan icke-jämviktsprocesser behöva beaktas, och adsorptions-databaser kan behöva utvecklas för att förbättra prediktionerna. Resultaten visar också att koncentrationen av upplöst organiskt kol, som uppvisar stora årstidsvariationer samt långsiktigt ökande trender på grund av klimatpåverkan i Arktis, kan ha stor inverkan på metallföroreningars transport. Observationer visade att enskilda våtmarker i Selengafloden lokalt kunde minska inkommande massflöden av metaller med 77 till 99 %. En systematisk genomgång av aktuellt kunskapsläge visade dock att storskaliga nettoeffekter kan skilja sig mycket från de funktioner som observeras vid enskilda våtmarker på mindre skalor. Längs storskaliga flödesvägar, genom vilka flera våtmarker är kopplade till varandra och till det större landskapet, kan viktiga processer ske, vilket avsevärt kan bidra till sådana skal-skillnader i funktion. En genomgång av aktuell våtmarksforskning visade att relativt få studier beaktade dessa större skalor där föroreningsspridning och vattenkvalitetsförändringar sker. Denna avhandling belyser behovet av ökat forskningsfokus på storskaliga våtmarkssystem. Detta kan hjälpa till att förstå föroreningars nettoeffekter på landskapsskalor, vilket underlättar vid bedömning av hur och när våtmarkssystem fungerar som storskaliga, så kallade naturbaserade lösningar.
Amvrosiadi, Nino. "The value of experimental data and modelling for exploration of hydrological functioning: The case of a till hillslope." Doctoral thesis, Uppsala universitet, Luft-, vatten och landskapslära, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-331856.
Full textRead, Tom Oliver Trevett. "Applications of distributed temperature sensing in subsurface hydrology." Thesis, University of East Anglia, 2016. https://ueaeprints.uea.ac.uk/59401/.
Full textBanwell, Alison Frances. "Modelling the hydrology of the Greenland Ice Sheet." Thesis, University of Cambridge, 2013. https://www.repository.cam.ac.uk/handle/1810/267715.
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