Academic literature on the topic 'Hydrology Hydrology Hydrologic models'

Mitigation of the hazards posed by debris flows requires an understanding of the mechanisms leading to their initiation. The objectives of this study were to evaluate and document the hydrologic response of a potential debris-flow source area to major rainstorms and to evaluate whether traditional models of hillslope hydrology can account for the observed response. A field site in an area of previous debris-flow activity was instrumented and monitored for two winter seasons. Hydrologic responses for a wide variety of antecedent conditions were recorded, including two storm events that produced well-defined positive pore-pressure pulses at the site and initiated numerous debris flows in the immediate vicinity of the site. The observed hydrologic response was highly dependent on antecedent moisture conditions which can be characterized by soil matric suction measurements. The pressure-head pulses observed had a magnitude of approximately 50 cm of water, were transient, traveled downslope, and exhibited some spatial variability. Traditional models of hillslope hydrology do not fully account for the positive pore-pressure pulses observed high on the hillslope. Key words: debris flow, hillslope hydrology, pore pressure, antecedent moisture, tensiometer, piezometer, field investigation.

Abstract. Recently, deep learning (DL) has emerged as a revolutionary and versatile tool transforming industry applications and generating new and improved capabilities for scientific discovery and model building. The adoption of DL in hydrology has so far been gradual, but the field is now ripe for breakthroughs. This paper suggests that DL-based methods can open up a complementary avenue toward knowledge discovery in hydrologic sciences. In the new avenue, machine-learning algorithms present competing hypotheses that are consistent with data. Interrogative methods are then invoked to interpret DL models for scientists to further evaluate. However, hydrology presents many challenges for DL methods, such as data limitations, heterogeneity and co-evolution, and the general inexperience of the hydrologic field with DL. The roadmap toward DL-powered scientific advances will require the coordinated effort from a large community involving scientists and citizens. Integrating process-based models with DL models will help alleviate data limitations. The sharing of data and baseline models will improve the efficiency of the community as a whole. Open competitions could serve as the organizing events to greatly propel growth and nurture data science education in hydrology, which demands a grassroots collaboration. The area of hydrologic DL presents numerous research opportunities that could, in turn, stimulate advances in machine learning as well.

Globally, cities in developing countries are urbanising at alarming rates, and a major concern to hydrologists and planners are the options that affect the hydrologic functioning of watersheds. Environmental impact assessment (EIA) has been recognised as a key sustainable development tool for mitigating the adverse impacts of planned developments, however, research has shown that planned developments can affect people and the environment significantly due to urban flooding that arises from increased paved surfaces. Flooding is a major sustainable development issue, which often result from increased paved surfaces and decreased interception losses due to urbanisation and deforestation respectively. To date, several environmental assessment studies have advanced the concept of alternatives, yet, only a small number of hydrologic studies have discussed how the location of paved surface could influence catchment runoff. Specifically, research exploring the effects of location alternative in EIAs on urban hydrology is very rare. The Greater Port-Harcourt City (GPH) development established to meet the growth needs in Port-Harcourt city (in the Niger Delta) is a compelling example. The aim of this research is to examine the relative effect of EIA alternatives in three different locations on urban hydrology. The Hydrologic Engineering Centre’s hydrologic modelling system (HEC-HMS) hydrodynamic model was used to generate data for comparing runoff in three different basins. HEC-HMS software combine models that estimate: Loss, transformation, base flow and channel routing. Results reveal that developments with the same spatial extent had different effects on the hydrology of the basins and sub-basins in the area. Findings in this study suggest that basin size rather than location of the paved surface was the main factor influencing the hydrology of the watershed.

Abstract. This paper introduces and presents the Spatial Processes in HYdrology (SPHY) model (v2.0), its development background, its underlying concepts, and some example applications. SPHY has been developed with the explicit aim of simulating terrestrial hydrology on flexible scales, under various physiographical and hydroclimatic conditions, by integrating key components from existing and well-tested models. SPHY is a spatially distributed leaky bucket type of model, and is applied on a cell-by-cell basis. The model is written in the Python programming language using the PCRaster dynamic modeling framework. SPHY (i) integrates most hydrologic processes, (ii) has the flexibility to be applied in a wide range of hydrologic applications, and (iii) on various scales, and (iv) can easily be implemented. The most relevant hydrological processes that are integrated into the SPHY model are rainfall–runoff processes, cryosphere processes, evapotranspiration processes, the dynamic evolution of vegetation cover, lake/reservoir outflow, and the simulation of root-zone moisture contents. Studies in which the SPHY model was successfully applied and tested are described in this paper, including (i) real-time soil moisture predictions to support irrigation management in lowland areas, (ii) climate change impact studies in snow- and glacier-fed river basins, and (iii) operational flow forecasting in mountainous catchments.

Abstract Studies seeking to understand the impacts of climate variability and change on the hydrology of a region need to take into account the dynamics of vegetation and its interaction with the hydrologic and energy cycles. Yet, most of the hydrologic models used for these kinds of studies assume that vegetation is static. This paper presents a dynamic, spatially explicit model that couples a vertical energy balance scheme (surface and canopy layer) to a hydrologic model and a forest growth component to capture the dynamic interactions between energy, vegetation, and hydrology at hourly to daily time scales. The model is designed to be forced with outputs from regional climate models. Lateral water transfers are simulated using a 1D kinematic wave model. Infiltration is simulated using the Green and Ampt approximation to Richard's equation. The dynamics of soil moisture and energy drives carbon assimilation and forest growth, which in turn affect the distribution of energy and water through leaf dynamics by altering light interception, shading, and enhanced transpiration. The model is demonstrated in two case studies simulating energy, water, and vegetation dynamics at two different spatial and temporal scales.

Abstract. Globally, many different kinds of water resources management issues call for policy and infrastructure based responses. Yet responsible decision making about water resources management raises a fundamental challenge for hydrologists: making predictions about water resources on decadal-to-century long timescales. Obtaining insight into hydrologic futures over 100 yr timescales forces researchers to address internal and exogenous changes in the properties of hydrologic systems. To do this, new hydrologic research must identify, describe and model feedbacks between water and other changing, coupled environmental subsystems. These models must be constrained to yield useful insights, despite the many likely sources of uncertainty in their predictions. Chief among these uncertainties are the impacts of the increasing role of human intervention in the global water cycle – a defining challenge for hydrology in the Anthropocene. Here we present a research agenda that proposes a suite of strategies to address these challenges. The research agenda focuses on the development of co-evolutionary hydrologic modeling to explore coupling across systems, and to address the implications of this coupling on the long-time behavior of the coupled systems. Three research directions support the development of these models: hydrologic reconstruction, comparative hydrology and model-data learning. These strategies focus on understanding hydrologic processes and feedbacks over long timescales, across many locations, and through strategic coupling of observational and model data in specific systems. We highlight the value of use-inspired and team-based science that is motivated by real-world hydrologic problems but targets improvements in fundamental understanding to support decision-making and management.

Abstract. The impacts of climate and land-use changes make the stationary assumption in hydrology obsolete. Moreover, there is still considerable uncertainty regarding the future evolution of the Earth’s climate and the extent of the alteration of flow regimes. Climate change impact assessment in the water sector typically involves a modelling chain in which a hydrological model is needed to generate hydrologic projections from climate forcings. Considering the inherent uncertainty of the future climate, it is crucial to assess the performance of the hydrologic model over a wide range of climates and their corresponding hydrologic conditions. In this paper, numerous, contrasted, climate sequences identified by a hidden Markov model (HMM) are used in a differential split-sample testing framework to assess the robustness of a hydrologic model. The differential split-sample test based on a HMM classification is implemented on the time series of monthly river discharges in the upper Senegal River basin in West Africa, a region characterized by the presence of low-frequency climate signals. A comparison with the results obtained using classical rupture tests shows that the diversity of hydrologic sequences identified using the HMM can help with assessing the robustness of the hydrologic model.

Abstract. HydroViz is a Web-based, student-centered, educational tool designed to support active learning in the field of Engineering Hydrology. The design of HydroViz is guided by a learning model that is based on learning with data and simulations, using real-world natural hydrologic systems to convey theoretical concepts, and using Web-based technologies for dissemination of the hydrologic education developments. This model, while being used in a hydrologic education context, can be adapted in other engineering educational settings. HydroViz leverages the free Google Earth resources to enable presentation of geospatial data layers and embed them in web pages that have the same look and feel of Google Earth. These design features significantly facilitate the dissemination and adoption of HydroViz by any interested educational institutions regardless of their access to data or computer models. To facilitate classroom usage, HydroViz is populated with a set of course modules that can be used incrementally within different stages of an engineering hydrology curriculum. A pilot evaluation study was conducted to determine the effectiveness of the HydroViz tool in delivering its educational content, to examine the buy-in of the program by faculty and students, and to identify specific project components that need to be further pursued and improved. A total of 182 students from seven freshmen and senior-level undergraduate classes in three universities participated in the study. HydroViz was effective in facilitating students' learning and understanding of hydrologic concepts and increasing related skills. Students had positive perceptions of various features of HydroViz and they believe that HydroViz fits well in the curriculum. In general, HydroViz tend to be more effective with students in senior-level classes than students in freshmen classes. Lessons gained from this pilot study provide guidance for future adaptation and expansion studies to scale-up the application and utility of HydroViz and other similar systems into various hydrology and water-resource engineering curriculum settings. The paper presents a set of design principles that contribute to the development of other active hydrology educational systems.

Abstract. Globally, many different kinds of water resources management issues call for policy- and infrastructure-based responses. Yet responsible decision-making about water resources management raises a fundamental challenge for hydrologists: making predictions about water resources on decadal- to century-long timescales. Obtaining insight into hydrologic futures over 100 yr timescales forces researchers to address internal and exogenous changes in the properties of hydrologic systems. To do this, new hydrologic research must identify, describe and model feedbacks between water and other changing, coupled environmental subsystems. These models must be constrained to yield useful insights, despite the many likely sources of uncertainty in their predictions. Chief among these uncertainties are the impacts of the increasing role of human intervention in the global water cycle – a defining challenge for hydrology in the Anthropocene. Here we present a research agenda that proposes a suite of strategies to address these challenges from the perspectives of hydrologic science research. The research agenda focuses on the development of co-evolutionary hydrologic modeling to explore coupling across systems, and to address the implications of this coupling on the long-time behavior of the coupled systems. Three research directions support the development of these models: hydrologic reconstruction, comparative hydrology and model-data learning. These strategies focus on understanding hydrologic processes and feedbacks over long timescales, across many locations, and through strategic coupling of observational and model data in specific systems. We highlight the value of use-inspired and team-based science that is motivated by real-world hydrologic problems but targets improvements in fundamental understanding to support decision-making and management. Fully realizing the potential of this approach will ultimately require detailed integration of social science and physical science understanding of water systems, and is a priority for the developing field of sociohydrology.

Abstract. This work addresses the impact of climate change on the hydrology of a catchment in the Mediterranean, a region that is highly susceptible to variations in rainfall and other components of the water budget. The assessment is based on a comparison of responses obtained from five hydrologic models implemented for the Rio Mannu catchment in southern Sardinia (Italy). The examined models – CATchment HYdrology (CATHY), Soil and Water Assessment Tool (SWAT), TOPographic Kinematic APproximation and Integration (TOPKAPI), TIN-based Real time Integrated Basin Simulator (tRIBS), and WAter balance SImulation Model (WASIM) – are all distributed hydrologic models but differ greatly in their representation of terrain features and physical processes and in their numerical complexity. After calibration and validation, the models were forced with bias-corrected, downscaled outputs of four combinations of global and regional climate models in a reference (1971–2000) and future (2041–2070) period under a single emission scenario. Climate forcing variations and the structure of the hydrologic models influence the different components of the catchment response. Three water availability response variables – discharge, soil water content, and actual evapotranspiration – are analyzed. Simulation results from all five hydrologic models show for the future period decreasing mean annual streamflow and soil water content at 1 m depth. Actual evapotranspiration in the future will diminish according to four of the five models due to drier soil conditions. Despite their significant differences, the five hydrologic models responded similarly to the reduced precipitation and increased temperatures predicted by the climate models, and lend strong support to a future scenario of increased water shortages for this region of the Mediterranean basin. The multimodel framework adopted for this study allows estimation of the agreement between the five hydrologic models and between the four climate models. Pairwise comparison of the climate and hydrologic models is shown for the reference and future periods using a recently proposed metric that scales the Pearson correlation coefficient with a factor that accounts for systematic differences between datasets. The results from this analysis reflect the key structural differences between the hydrologic models, such as a representation of both vertical and lateral subsurface flow (CATHY, TOPKAPI, and tRIBS) and a detailed treatment of vegetation processes (SWAT and WASIM).

Thesis (Ph. D.)--Ohio State University, 2003.
Title 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

El principal objectiu d'aquesta investigació és estudiar la dinàmica hidrològica d'una conca Mediterrània
afectada 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.

The level of spatial and vertical detail of important hydrologic processes within a watershed that needs to be represented by a conceptual rainfall-runoff (CRR) model in order to accurately simulate the streamflow is not well understood. The paucity of high-resolution hydrologic information in the past guided the direction of model development to more accurately represent processes directly related to the vertical movement of moisture within the watershed rather than the spatial variability of these processes. As a result, many of the CRR models currently available are so complex (vertically), that expert knowledge of the model and watershed system is required to successfully estimate values for model parameters using manual methods. Automatic parameter estimation procedures, developed to reduce the time and effort required with manual methods, do not provide parameter estimates and hydrograph simulations that are considered acceptable by the hydrologists responsible for operational forecasting. Newly available, high-resolution hydrologic information may provide insight to the spatial variability of important rainfall-runoff processes. However, effective and efficient methods to incorporate the data into the current modeling strategies need to be developed. This work describes a new hybrid multicriteria calibration approach that combines the strength of automatic and manual calibration methods. The new approach was used to investigate the benefits of different levels of spatial and vertical representation of important watershed hydrologic variables with conceptual rainfall runoff models.

The ability to simulate snow accumulation and melting processes is fundamental to developing real-time hydrological models in watersheds with a snowmelt-dominated flow regime. A primary source of uncertainty with this model development approach is the subjectivity related to which historical periods to use and how to combine parameters from multiple calibration events. The Hydrologic Engineering Center, Hydrological Modeling System, has recently implemented a hybrid temperature index (TI) snow module that has not been extensively tested. This study evaluates a radiatative temperature index (RTI) model’s performance relative to the traditional air TI model. The TI model for Willow Creek performed reasonably well in both the calibration and validation years. The results of the RTI calibration and validation simulations resulted in additional questions related to how best to parameterize this snow model. An RTI parameter sensitivity analysis indicates that the choice of calibration years will have a substantial impact on the parameters and thus the streamflow results. Based on the analysis completed in this study, further refinement and verification of the RTI model calculations are required before an objective comparison with the TI model can be completed.