The management of New Zealand’s freshwater resources has come under increasing pressure from different industrial and environmental stakeholders. Land use change and the pressure it can put on water resources has been a significant issue regarding resource management in New Zealand. A significant mechanism driving land use change has been the growth of forestry, dairy farming, and other agricultural industries. Improvements in agricultural and forestry science and irrigation techniques have allowed new, previously less arable areas of New Zealand to be subject to land use change, such as the conversion of tussock grassland to pasture in steep, mountainous regions in the South Island. Studies regarding the effects of land use change in such catchments, especially with focus on flood hydrology, appear to be limited, despite the importance of managing catchment headwaters to minimise flood risk downstream. The TopNet model was used in this research project to evaluate the potential effects of land use change on flood hydrology in mountain catchments. It is a semi-distributed continuous rainfall-runoff model developed by the National Institute of Water and Atmospheric Research (NIWA). It has been widely used in New Zealand, and applications have included modelling water yield and the effect of climate change in catchment networks. However, it was not developed specifically for predicting flood flows. Hence, testing the model for flood peak prediction in mountainous catchments was also performed, and may show that TopNet can be a useful tool in resource management in New Zealand. The Ahuriri and Pelorus River catchments were used in this investigation. Both are steep catchments located in the South Island. The Ahuriri River catchment, in the Waitaki Basin on the eastern side of the Southern Alps, is a semi-arid catchment dominated by tussock grassland. The surrounding catchments are heavily influenced by infrastructure for hydroelectric power (HEP) generation and more recently irrigation for dairy farming. The Pelorus River catchment is located at the northern end of the South Island. It is primarily covered in native forest, but adjacent catchments are subject to agricultural and forestry development. The ability of the TopNet model for each catchment to predict flood flows were tested using a selection of historical flood events. Rainfall input to the model was at a daily timestep from the virtual climate station network (VCSN), and the method of disaggregating the daily estimate into an hourly rainfall series to be used by the model was found to have a significant influence on flood prediction. Where an accurate historical rainfall record was provided from a rainfall gauge station within the catchments, the disaggregation of the daily rainfall estimate based on the station data produced a significantly more accurate flood prediction when compared to predictions made using a stochastic disaggregation of the daily rainfall estimate. The TopNet models were modified to reflect land use change scenarios: the conversion of tussock grassland to pasture and the afforestation of tussock in the Ahuriri River catchment, and the conversion of forested land to pasture and the harvest of plantation forestry in the Pelorus River catchment. Following a past study into modelling the effects of land use change using TopNet, three key model parameters were modified to reflect each land use scenario: saturated hydraulic conductivity KS, canopy storage capacity, and the canopy enhancement factor. Past studies suggested a wide range of suitable values for KS, although also acknowledged that KS depends heavily on the specific catchment characteristics. A sensitivity analysis showed that KS had a significant influence on flood peak prediction in TopNet. It is recommended that further investigation be conducted into suitable values for KS. TopNet appeared to predict the effect of land use change on flood magnitude in mountainous catchments conservatively. Past studies of land use change suggested that the effect on flood flows should be significant, whereas TopNet generally predicted small changes in flood peaks for the scenarios in each catchment. However, this may suggest that the topography, geology, and soil properties of steep catchments are more important to flood hydrology than land cover. Further investigation into the effect of such catchment characteristics is recommended. Nevertheless, TopNet was shown to have the potential to be a useful tool for evaluating and managing the effects of land use change on the flood hydrology of mountainous catchments in New Zealand.

This thesis applies the runoff process in ostrovská Bystřice river catchment in Ore Mountains. For this purpose we used runoff precipitation model HEC-HMS. Our specific goal is to model the soil runoff, which is observed on eleven runoff precipitation events in the period 2009 - 2013. We analyzed basic physical characteristics of soils, which occur in observed river basin. The results were afterwards used to set up parameters of studied methods. We found out, that the moisture from antecedent precipitation influences modeling of soil runoff. The antecedent precipitation conditions the change of basic physical characteristic. We disregarded the influence of evapotranspiration and effect of vegetation on soil runoff. For the parameterization we have chosen two methods, which describe soil runoff. It was SCS CN and Green Ampt methods. These two methods have been compared on sample of resulting events. The methods were manually and automatically calibrating. The results showed on the insignificant difference between both observed methods. No better significant predicative capacity was manifested for one or other methods. Key worlds: soil runoff modeling, SCS CN, Green Ampt, HEC-HMS, infiltration

This work deals with the modelling of runoff processes in the experimental Bystřice river catchment in the Krušné Mountains. Rainfall-runoff model WaSiM (Topmodel version) was used for this purpose.Objective of this study was modelling snow accumulation and snowmelt in winter periods 2009/2010 and 2010/2011. Sensitivity analysis of TOPMODEL parameters was performed using Monte Carlo and GLUE methodology. Wasim was calibrated manually for 25 and 250 m grid scales and daily timestep. Results of simulations in both spatial scales different spatial scales differed significantly. Better performance of modelling in finer scale wasn't proved in validation of the model. Results of the simulations pointed out uncertainty in model calibration. Rasters of modeled snow water equivalent were also analyzed in selected days representing periods of snow accumulation and snowmelt. The goal was to examine the functioning of used snow model (combination of temperature index method and energy balance method) within the WaSiM frame. Finer scale raster proved to be practical for this purpose It was found that the spatial heterogeneity in the distribution of snow is determined by evapotranspiration and also by effect of radiation correction (in the case of rainfall).Influence of interception and vegetation effects on...

This thesis deals with rainfall and water runoff regime in the catchment area of river Klabava. The aim of this thesis is to find changes in the rainfall-runoff regime during the period of observations (1950-2014) and if so, were these changes caused by climate changes or human activities. The research part includes description of rainfall-runoff process and Klabava catchment area description. In the applied part there is an analysis of precipitation - runoff regime for long-term time series of average and minimal annual, monthly and seasonal discharges and annual, monthly and seasonal precipitations using single and double mass curves and statistical tests testing absolute homogeneity, relative homogeneity and trend (by Mann-Whitney-Pettit, Alexandersson, Mann-Kendall tests). The tests were performed by freely available software AnClim designed for these purposes. Mann-Kendall test was performed by MULTMK/PARTMK available as a MS Excel macro for free. Plus, there is basic discussion of floods in Klabava river basin and flood seasonality. The homogeneity tests haven't found many changes at all, most of the detected changes concern the minimal runoff time series. The precipitation annual amount was detected with a raising trend, while the runoff time series seem to have no trend at all. Achieved...

Nos últimos anos os modelos hidrológicos distribuídos vêm ganhando espaço por permitirem que a variabilidade espacial das características das bacias hidrográficas seja incorporada no processo de transformação chuva-vazão. Porém, devido a essa capacidade, os modelos distribuídos tendem a ser matematicamente complexos, impondo que muitos parâmetros sejam medidos ou estimados. Apesar de a literatura apresentar diversos trabalhos que tentem verificar o nível de detalhamento mais adequado à representação dos diversos sistemas, as conclusões são contraditórias, mostrando que há necessidade de estudos mais aprofundados. O presente trabalho propõe e avalia diferentes níveis de detalhamento na representação da bacia hidrográfica do Córrego do Gregório, na cidade de São Carlos, SP, submetida aos processos hidrológicos intervenientes na transformação chuva-vazão, empregando o modelo hidrológico Storm Water Management Model - SWMM. A calibração dos eventos, necessária a adequação dos parâmetros do modelo, utilizou como ferramenta os algoritmos genéticos, produzindo resultados satisfatórios, com coeficientes de eficiência de Nash e Sutfliffe (1970) entre 0,74 e 0,87, variáveis de evento para evento. De uma forma geral, os resultados obtidos com a análise dos diferentes níveis de detalhe evidenciaram a importância da consideração da micro-drenagem na representação dos sistemas. Para os eventos mais freqüentes submetidos à análise quanto maior o detalhe imposto na representação da bacia, maior a velocidade de escoamento resultante da baixa rugosidade das galerias pluviais, e, portanto, maiores vazões de pico foram encontradas. Os resultados ressaltaram também a influência das áreas impermeáveis sobre os hidrogramas, ratificando a importância da determinação criteriosa desse parâmetro. / For the last years, the distributed hydrological models have been recognized by allowing the incorporation of the spatial variability of catchment characteristics for rainfall-runoff simulation. However, due to this ability, the distributed models tend to be mathematically complex and to require many parameters to be measured or estimated. Although the literature presents several works that attempt to ascertain the level of discretization more appropriate to represent the various systems, the results are contradictory, showing the need for further studies. This work proposes and evaluates different levels of representation of the watershed of the Gregory Creek in the city of São Carlos, SP, under rainfall-runoff simulation, by applying the hydrologic model Storm Water Management Model - SWMM. The calibration of the events, needed to adequacy the model parameters, used as tool the genetic algorithm, producing satisfactory results, with values of Nash and Sutcliffe (1970) efficiency coefficients ranging between 0,74 and 0,87, varying from event to event . In general, the results showed the importance of considering the micro-drainage in the systems representation. For more frequent events, by increasing the level of catchment representation, the velocity of flow became greater, resulted from the low roughness of the conduits, and, therefore, higher peak flows rates were found. The results also emphasized the influence of the impervious areas on the hydrographs, confirming the great importance of careful determination of this parameter.

O problema de escassez da água para o abastecimento humano vem se agravando a cada ano que passa. As demandas vem crescendo e precisam ser supridas da melhor maneira possível sob pena de limitar o processo de desenvolvimento regional. Para tanto, deve-se recorrer ao planejamento e gerenciamento dos recursos hídricos como forma de se promover ao seu uso racional. Descreve-se neste trabalho a implantação de um sistema de apoio ao planejamento e gerenciamento de recursos hídricos, dando uma maior ênfase ao modelo hidrológico distribuído utilizado para gerar as vazões na bacia hidrográfica. Avalia-se sua calibração e validação realizada com dados fluviométricos e de níveis de açudes. Apresentam-se os resultados de estudo de potencialidade da bacia hidrográfica, e por último as disponibilidades dos principais açudes. Todas estas etapas formam realizadas tendo sempre a visão especializada e integrada da bacia hidrográfica do rio do Peixe. / The problem of scarcity of water for human supply has increased each year. The needs have increased and must be fullfilled as satisfactory as possible. If not the development process ofthe region could be limited. In this way, we must use the planning and management of water resources to promote a rational use. This dissertation describes the implantation of a support system to the planning and management of water resources, focusing the hydrologic distributed model used to generate the inflows in the basin. The calibration and validation processes with sets of data formed by gauge stream go stations and reservoir levels are analyzed. The results of a study of the potentiality of the basin, and finally the availability of the mains reservoirs are presented. All this steps were made with a specialized and integrated view of the Peixe river basin.

O problema de escassez da água para o abastecimento humano vem se agravando a cada ano que passa. As demandas vem crescendo e precisam ser supridas da melhor maneira possível sob pena de limitar o processo de desenvolvimento regional. Para tanto, deve-se recorrer ao planejamento e gerenciamento dos recursos hídricos como forma de se promover ao seu uso racional. Descreve-se neste trabalho a implantação de um sistema de apoio ao planejamento e gerenciamento de recursos hídricos, dando uma maior ênfase ao modelo hidrológico distribuído utilizado para gerar as vazões na bacia hidrográfica. Avalia-se sua calibração e validação realizada com dados fluviométricos e de níveis de açudes. Apresentam-se os resultados de estudo de potencialidade da bacia hidrográfica, e por último as disponibilidades dos principais açudes. Todas estas etapas formam realizadas tendo sempre a visão especializada e integrada da bacia hidrográfica do rio do Peixe. / The problem of scarcity of water for human supply has increased each year. The needs have increased and must be fullfilled as satisfactory as possible. If not the development process ofthe region could be limited. In this way, we must use the planning and management of water resources to promote a rational use. This dissertation describes the implantation of a support system to the planning and management of water resources, focusing the hydrologic distributed model used to generate the inflows in the basin. The calibration and validation processes with sets of data formed by gauge stream go stations and reservoir levels are analyzed. The results of a study of the potentiality of the basin, and finally the availability of the mains reservoirs are presented. All this steps were made with a specialized and integrated view of the Peixe river basin.

The temporal dynamics of hydrological model performance gives insights into errors that cannot be obtained from global performance measures assigning a single number to the fit of a simulated time series to an observed reference series. These errors can include errors in data, model parameters, or model structure. Dealing with a set of performance measures evaluated at a high temporal resolution implies analyzing and interpreting a high dimensional data set. This paper presents a method for such a hydrological model performance assessment with a high temporal resolution and illustrates its application for two very different rainfall-runoff modeling case studies. The first is the Wilde Weisseritz case study, a headwater catchment in the eastern Ore Mountains, simulated with the conceptual model WaSiM-ETH. The second is the Malalcahuello case study, a headwater catchment in the Chilean Andes, simulated with the physicsbased model Catflow. The proposed time-resolved performance assessment starts with the computation of a large set of classically used performance measures for a moving window. The key of the developed approach is a data-reduction method based on self-organizing maps (SOMs) and cluster analysis to classify the high-dimensional performance matrix. Synthetic peak errors are used to interpret the resulting error classes. The final outcome of the proposed method is a time series of the occurrence of dominant error types. For the two case studies analyzed here, 6 such error types have been identified. They show clear temporal patterns, which can lead to the identification of model structural errors.

The hydrology of the Canadian Prairies has been well described in the scientific literature. 20th C observations show that snowmelt over frozen soils accounted for over 80% of the annual runoff, and streamflow hydrographs peaked in April and ceased in May due to a lack of runoff or groundwater contributions. Since then, the region has undergone rapid changes in land use and climate, both which affect streamflow generating processes. This study evaluates the detailed hydrological impact of regional changes to climate on an instrumented research catchment, the Smith Creek Research Basin (SCRB); an unregulated, wetland and agriculture dominated prairie catchment in south-eastern Saskatchewan. Wetlands have been drained for decades, reducing wetland extent by 58% and maximum storage volume by 79%, and increasing drainage channels lengths by 780%. Long term meteorological records show that there have been gradual changes to the climate: though there are no trends in annual precipitation amount, increasing temperatures since 1942 have brought on a gradual increase in the rainfall fraction of precipitation and an earlier snowmelt by two weeks. In the summer months, the number of multiple day rainfall events has increased by 5 events per year, which may make rainfall-runoff generation mechanisms more efficient. Streamflow records show that annual streamflow volume and runoff ratios have increased 14-fold and 12-fold, respectively since 1975, with major shifts in 1994 and 2010. Streamflow contributions from rainfall-runoff and mixed-runoff regimes increased substantially. Snowmelt runoff declined from 86% of annual discharge volume in the 1970’s to 47% recently while rainfall runoff increased from 7% to 34%. Annual peak discharge tripled over the period from 1975 to 2014, with a major shift in 1994, while the duration of flow doubled in length to 147 days after a changepoint in 1990. Recent flooding in the SCRB has produced abnormally large streamflow volumes, and flooding in June 2012 and 2014 was caused solely by rainfall, something never before recorded at the basin. Although the observed changes in climate and wetland drainage are substantial, it is unlikely that a single change can explain the dramatic shifts in the surface hydrology of the SCRB. Further investigation using process hydrology simulations is needed to help explain the observed regime changes.

Project Completion Report, OWRT Project No. A-049-ARIZ / Agreement No. 14-31-0001-4003 / Project Dates: July 1, 1973 - June 30, 1974. / Acknowledgement: The work upon which this report is based was supported by funds provided by the United States Department of the Interior, Office of Water Research and Technology, as authorized under the Water Resources Research Act of 1964. / A non-linear reservoir model is used to represent the rainfall-runoff relationships for thunderstorms on the urban watersheds of Tucson, Arizona. Two types of computer programs are developed: a calibration program to obtain a best -fit calculated hydrograph; and a verification program to generate storm hydrographs given the watershed characteristics and a hyetograph. Calibration reveals the relationship of the model parameters, namely, (f) the inflow coefficient, (a) the constant coefficient, and (TL) the time lag, to the total rainfall, drainage area, channel length, and infiltration capacity of the watershed. The average discrepancy between the predicted hydrograph and the actual hydrograph for Tucson urban watersheds is 20 -25 percent.