The aim of the thesis was the creation and interpretation of thematic layers for the Ostřice stream catchment. First step was collecting all the available maps and comparing them with the actual state. The documents were digitized, and the thematic layers were created. The map outputs were created from these layers and their combinations and were analyzed. The output of this work is a set of GIS layers for the Ostřice stream catchment. This work was processed with the ArcGIS Desktop 9.1 software.

The influence of precipitation on runoff characteristics of tile drainage systems and nitrate concentrations in drainage water were evaluated in this thesis. The Jeninsky stream catchment is located at the foothill of Sumava Mountains near the border checkpoint Dolni Dvoriste. Extensive agriculture (pasture) is practised in the catchment as well as surrounding areas. Above mentioned evaluated characteristics were measured on two closure profiles of tile drained subcatchments. Discharges were measured continously, water quality was sampled forthnigtly. Evaluated hydrologic year 2007 was rich in rainfall {--} the precipitation amounted to 892 mm, which is classified as a wet year, despite of 41 days long dry period. Runoff characteristics don{\crq}t vary much in both subcatchments, due to similar area and land use on researched catchments. Long dry period did not cause zero discharges. The progress of nitrate concentrations in subcatchments is characterized by low variations in values. Relatively low values (90-percentil of nitrate concentrations in individual catchments belong to II. and III. class of water quality limits set by Czech legislative) occured in the catchment. These values correspond or slightly exceed values monitored on surrounding simirarly used areas, but are significantly lower than values monitored in areas, where intensive agriculture is practised. This confirms positive influence of grassing on nitrate pollution of drainage and surface water.

There are remarkable changes in water quality at the Jenínský stream catchment that lies in the Šumava foothills which were caused by change in land use. Two subcatchments, called J1 and J2, were monitored. In the first period 1983-1985, the two subcatchments were agriculturaly used, the land was fertilized and ploughed and cereals and corn were grown. In the second period 2004-2008, there were grasslands and the land was extensively used as pasture. This change in land use caused evident changes in water quality at the Jenínský stream catchment. The decrease of all monitored indices was remarkably seen in the concentrations of nitrate and ammonium. The average nitrate concentration in 1983-1985 was 39,5 mg . l-1, and decreased by 43,3% to the value of 16,9 mg . l-1 in 2004-2008. The greatest decrease of 85,9% was found in average ammonium concentration (0,4 mg . l-1 dropped to 0,05 mg . l-1). The positive effect of the change from arable land to grassland was confirmed and we can see it in the amount of nitrogen compounds and resulting improvement of water quality.

The purpose of this work was to present the computer supported hydrological simulation. The methods are demonstrated on the Jenínský stream catchment, which serves as an experimental catchment of the Depatment of Land Adjustement, Faculty of Agriculture, University of South Bohemia since 2004. The hydrological analyses are solved in the ArcGIS 9.2 software, ArcView level and its extension ArcHydro. Digitized contour lines layers, watershed divide and the stream were used as a basis for functionality testing. Subsequently the results were compared with the reality, and the possible differences were discussed. The result is evaluation of the use of particular tools of the mentonioned software for the tasks solved in catchment hydrology. This work will also be used as a guideline for the use of ArcHydro for the extension of the education of modelling in the subjects concerning catchment hydrology.

The subject of this thesis is the erosion control as the element of the ecologic stability. The target of this thesis is to determine the amount of the soil, which is being lost from lands in Štěkře cadastral area as consequence of the surface runoff. I use the universal soil loss equation from Wischmeier and Smith for calculations. I also calculate the cubature runoff from the micro catchment area according to Čerkašin and the transport of floating solids according to Williams and Berndt. I propose the antierosion precautions for lands which have got the measure of erosion bigger then acceptable value. I compare all findings before and after the antierosion precautions.

Na maior parte dos ecossistemas aquáticos a respiração excede a produção primária bruta autóctone, acarretando uma produção líquida de ecossistema negativa. Estudos recentes atribuem essa condição a processos de degradação de matéria orgânica alóctone, portanto o ciclo do carbono em corpos de água interiores deve estar pareado com o aporte de carbono orgânico originado na bacia hidrográfica. Este trabalho contribui para a melhor compreensão dos processos atuantes no ciclo de carbono em bacias hidrográficas, por meio de monitoramento de dados de campo, desenvolvimento e aplicação de modelagem matemática e simulação numérica. O estudo foi realizado utilizando dados de monitoramento na bacia hidrográfica do Rio Ijuí localizada no planalto meridional gaúcho. A exportação fluvial de carbono orgânico e inorgânico foi estimada a partir de dados de vazão e concentração. Um modelo baseado em processos para simulação da dinâmica de carbono, MGB-IPH-C, foi desenvolvido e acoplado ao modelo hidrológico MGB-IPH. O modelo hidrológico foi ajustado em diversos pontos de controle na bacia hidrográfica do Ijuí obtendo-se bons resultados, principalmente para as bacias de maior porte (>1000 km2). O modelo de carbono foi avaliado qualitativamente considerando a representação de processos conceituais e, quantitativamente, pela comparação das concentrações e fluxos simulados em relação aos obtidos pelos dados do monitoramento. Não foi possível identificar associações diretas entre as concentrações de carbono inorgânico ou orgânico e vazão, com base nos dados medidos em campo. As cargas médias de carbono nas bacias estudadas apresentaram valores abaixo da média global, na ordem de 25-40 kg.ha-1.ano-1 e 8-10 kg.ha-1.ano-1, para as frações inorgânica e orgânica, respectivamente. O MGB-IPH-C representou processos conceituais esperados, em especial, a acumulação no solo e o efeito da lavagem das águas sobre a concentração dos rios. Foi possível obter bons ajustes em escala anual para as cargas e concentrações médias de carbono na bacia de estudo. A simulação da dinâmica de carbono em ecossistemas aquáticos em pareamento com a bacia hidrográfica utilizando modelos conceituais determinísticos contribui para o entendimento dos processos operantes nesses sistemas e deve ser complementada por meio de análise de dados de monitoramento, em freqüência adequada à escala, com métodos empíricos. / In most aquatic ecosystems respiration exceeds autochtonous gross primary production leading to a negative net ecosystem production. Recent studies attributes this condition to allochtonous organic matter degradation processes, so the inland water carbon cycle should be linked to the input of organic carbon from the catchment. This work contributes to a better comprehension of processes operating in the carbon cycle in river basins, throughout development and application of mathematical modeling and numerical simulation. The study was conducted using data of the Ijuí river watershed, located in the Planalto Meridional Gaúcho. Fluvial exports of organic and inorganic carbon were estimated from data measured in field. A process-based model for carbon dynamics simulation, MGB-IPH-C, was developed and coupled to the hydrological model MGB-IPH. The hydrological model was calibrated to various control points in the Ijui river basin with good results, especially in larger subwatersheds (>1000 km2). The carbon model was evaluated considering the representation of carbon dynamics conceptual processes and by comparison of observed carbon concentrations and export rates obtained by simulation and monitoring data. The estimates of annual export of carbon in the study area were below the global average, in magnitude of 25-40 kg/ha.yr and 8-10 kg/ha.yr for inorganic and organic carbon, respectively. The proposed carbon model, MGB-IPH-C, was able to simulate expected conceptual processes, in particular, the build-up on soil and the effect of wash-off on carbon concentration in river reaches. It was possible to obtain good fits for annual average carbon fluvial export rates and concentrations. The simulation of carbon dynamics in inland waters coupled with the watershed using conceptual deterministic models contributes to the understanding of processes operating on these systems and may be complemented throughout analysis of field data, at frequency appropriated to the scale, with empirical methods.

A construção civil ocupa uma posição muito importante no contexto da degradação ambiental, a qual o Planeta vem assistindo nas últimas décadas, sendo responsável por uma parcela significativa do consumo total de recursos naturais. Além disso, considerando uma análise do ciclo de vida de edifícios, a fase de uso dos mesmos tem tomado crescente importância no impacto total gerado pela edificação. Alterações no ciclo hidrológico e poluição dos meios hídricos são exemplos de importantes impactos gerados pelo uso de edificações. Em meio urbano são co-responsáveis também pelas cheias e inundações, que com freqüência geram importantes perdas humanas e materiais. Soluções técnicas alternativas têm sido desenvolvidas e apresentadas pelo mundo. Porém mostram-se pouco adaptáveis às condições nacionais, entre outros, por causa do aspecto econômico, muito importante em países subdesenvolvidos como o Brasil. Neste sentido, a pesquisa objetiva uma caracterização dos benefícios diretos e indiretos decorrentes da implantação de sistemas de captação e aproveitamento de água da chuva, para utilização não potável, em meio urbano, principalmente sob o aspecto econômico. Para tanto, revisa alguns aspectos relativos à contextualização e à viabilidade técnica destes sistemas, apresentando desde o tema da água no planeta até suas interações mais objetivas, no meio urbano. Um estudo experimental, sobre a edificação denominada Protótipo Alvorada, é desenvolvido em paralelo, a fim de ilustrar e balizar os estudos das variáveis dimensionais do sistema, dos números de chuva, neste caso para Porto Alegre/RS, e também o levantamento dos principais tipos e componentes de sistemas existentes. Os resultados para os benefícios diretos, sobre o aspecto econômico, demonstram em geral que o custo de implantação do sistema é o maior entrave à sua aplicação. Este fato deve-se, em grande parte à disponibilidade do recurso em Porto Alegre, entregue dentro das residências por um baixo custo. O estudo em torno dos benefícios indiretos revelou o potencial do sistema como auxiliar na drenagem urbana. Dependendo ainda de estudos mais aprofundados, o sistema conta com a possibilidade receber subsídio público para sua implantação, gerando economia para o mesmo e maximizando também o benefício direto. / During the past few decades the building industry was becoming increasingly responsible for a large portion of environmental degradation. In addition, considering the life cycle analysis of buildings, the building utilization phase is gaining importance in building environmental impact. Alterations in the water cycle, often resulting in human and economic loses because of urban flooding, is an example where the building utilization phase plays a significant role in environmental degradation. One answer to these problems is alternative technical solutions that are being developed and presented to environmental forums throughout the world; however, most of the alternative solutions are not economically feasible for sub-developed countries like Brazil. The objective of this research is to characterize the direct and indirect benefits provided by residential urban rainwater catchment systems and the implementation for non-potable use in the urban environment for economic gain. Towards this goal, the dissertation reviews some contexts and technical viability concerns about urban water interactions and drainage systems. A study, developed simultaneously with the research, was conducted on the building Protótipo Alvorada to gain an understanding of the variables of system dimensions, rain water distribution and volume. The study also explores existing systems, principal types of systems and components of existing systems. The results of this study have shown that, from an economic standpoint, the cost of system implementation is generally the main barrior to implemention of rainwater catchment systems. One reason that rainwater catchment systems are not economically feasible choice for the city of Porto Alegre is in large part due to the availability of potable water in the city. Water distribution to residences within the city is very inexpensive and widely available. The study about the indirect benefits of rainwater catchment systems has shown the potential of systems to help alleviate urban drainage problems. Despite the necessity for further studies, the feasibility of system implementation here in Porto Alegre/RS counts on the possibility of initial public funding in order to maximize the direct benefits of catchment systems. Installation of rainwater catchment systems would ultimately save money for the municipal government of Porto Alegre.

Water is a basic necessity for sustaining life and development of society. Proper management, protection and exploitation of water resources are the challenges imposed by population growth, increasing pressure on the water and land resources by competing usage. A good amount of clean water exists on Earth although it is normally inadequate in supply because of anthropogenic activities such as deforestation and land use change. Like many other catchments that provide economic activities for the community’s livelihood, the Chalimbana river catchment in Zambia has been deforested heavily and most of the local communities believe that deforestation could be the main contributing factor to the drying up of Chalimbana River. The objective of this study was to analyse the impact of deforestation on the stream flow of Chalimbana River Catchment with the help of a conceptual hydrological model, HBV. There was a 24% reduction in the annual average rainfall amounts for the deforested period as compared to the period before deforestation. The Qrec/Qsim ratios had revealed that the annual stream flow generation for the period after deforestation (1987 to 1996) for the Chalimbana River had decreased by about 12% as compared to the period with enough forest cover (1975 to 1985). The ratio of annual Qrec/P had indicated that after a 30% forest loss in Chalimbana catchment, there was a 33% increase in the generation of the stream flow. Based on the results that were obtained, a number of recommendations aiming at improving the catchment management were made.

Transport of chemical substances through a catchment depend to a large extent on the water content of the soil through which they are transported. When the groundwater level rise and fall, redox conditions change in the soil and the transport of substances is affected. The aim of this study is to develop a hydrological model which is able to simulate soil water content at different depths and groundwater level in a soil profile. A new type of conceptual model is developed, which uses a continous represenation of the soil and soil water from the soil surface down to the bedrock. The model is intended to be applied on small catchments at a later stage. The results show that the simulation of groundwater levels was greatly improved compared to previous results. Simulation of soil water content at selected depths is not yet satisfactory. The runoff simulation was accurate at one of the sites but did not work as well at the other. At one of the sites it was also possible to combine good simulations of runoff and groundwater levels but at the other it was only possible to obtain acceptable simulations of either runoff or groundwater. It is suggested that model performance could be improved by letting the porosity decrease and the soil water content increase non-linearly with depth. Calculations of evaporation from soil and runoff also need to be modified.

O ciclo do nitrogênio vem sendo alterado pelas atividades antropogênicas, em função do incremento de culturas, como as leguminosas, a queima de combustíveis fósseis e o desmatamento de florestas para uso agrícola e pecuário. Em regiões de climas temperados, existem muitas informações sobre o ciclo biogeoquímico deste elemento e sobre o papel das alterações antropogênicas no mesmo. Entretanto, em regiões tropicais, onde o ritmo do desmatamento ainda é intenso, poucas são as informações sobre este elemento. Em função disto, o presente trabalho visa fornecer informações sobre possíveis alterações nas formas de nitrogênio transportadas por pequenos igarapés, após a conversão de florestas em pastagens de regiões tropicais. Para tal, selecionaram-se duas microbacias, uma coberta com floresta primária e outra com pastagem, no estado de Rondônia (Cacaulândia). Em ambas foram realizados balanços, por eventos de chuva, das formas e quantidades de nitrogênio transportadas desde a precipitação até a água dos rios. As coletas foram realizadas durante a estação chuvosa, de 21 de janeiro a 27 de fevereiro de 2004. Como resultado, observou-se: (1) um maior fluxo de água na microbacia da pastagem, e como conseqüência, uma maior exportação de nitrogênio na mesma; (2) diferenças nas formas de nitrogênio predominantes em cada compartimento estudado. O nitrogênio orgânico dissolvido predominou na precipitação interna, no escoamento superficial e nos igarapés, enquanto que, o amônio predominou na água subsuperficial e na água subterrânea; (3) diferenças nas formas de nitrogênio inorgânico dissolvido presentes nos igarapés de cada microbacia, sendo o nitrato a principal forma observada na floresta, e o amônio na pastagem; (4) o nitrogênio orgânico dissolvido no igarapé da pastagem provem principalmente do escoamento superficial, enquanto que, no igarapé da floresta não foi possível identificar a principal fonte desta forma de nitrogênio. Este estudo mostra mudanças significativas no ciclo do nitrogênio como conseqüência do desmatamento e da implantação de pastagens. / The nitrogen cycle has been altered by anthropogenic activities, in response to the increment of cultures such, as the leguminous, fossil fuel use, and deforestation for agricultural uses and cattle raising. In temperate regions, there is considerable information about the biogeochemical cycle of nitrogen and the role of anthropogenic alterations on this cycle. However, in tropical regions, where deforestation rates are significant, there is little available information about these processes. The objective of the present work was to provide information on possible alterations in nitrogen forms transported in small catchments (igarapés) of tropical regions, after the conversion of forests into pastures. Two small catchments, one covered by primary forest, and another one covered by pasture, were selected in Rondonia State (Cacaulândia). At both catchments, balances of nitrogen forms and of quantities transported from the rain water to the rivers were calculated, employing a rain event approach. Sampling was done during the wet season, from January 21 to February 27, 2004. We observed: (1) higher discharges at pasture catchment, which resulted in larger nitrogen fluxes; (2) differences in the predominant nitrogen forms at each studied compartment. Dissolved organic nitrogen predominated in the internal precipitation, overland flow, and stream water, while ammonium predominated in the subsurface water and groundwater; (3) differences in the predominat dissolved inorganic nitrogen forms in stream waters of each catchment, nitrate in the forest, and ammonium in the pasture; (4) Dissolved organic nitrogen in the pasture stream comes primarily from overland flow but, for the forest stream, it was not possible to clearly identify the main source of this nitrogen form. This study shows significant changes in nitrogen cycling in small tropical catchments, as a result of deforestation for pasture.