Iškritus krituliams ant žemės paviršiaus, dalis jų susigeria į gruntą, o kita dalis nuolydžio kryptimi teka link žemiausių reljefo vietų. Susigėrimo intensyvumas priklauso nuo grunto laidumo. Sunkiuose gruntuose vandens susigeria ir patenka į gilesnius grunto sluoksnius gana sunkiai dėl mažo grunto laidumo. Intensyviausiai vanduo nuo žemės paviršiaus teka drenažo tranšėjomis ir šalia jų. Šios vandens tekėjimo sąlygos tranšėjose susidaro pakitus grunto struktūrai, jas užverčiant. Laikui bėgant, drenažo tranšėjoje atsiradę plyšiai užnešami smulkiomis grunto dalelėmis. Tai įtakoja grunto vandens laidumo savybių prastėjimą. Norint pagerinti vandens nutekėjimą iš viršutinio dirvožemio sluoksnio, padėtų natūralios gamtoje sutinkamos medžiagos, įterptos skersai virš vamzdinio drenažo. Drenažo tranšėjų užpylimui naudojant poringas medžiagas, dalis atitekėjusio vandens akumuliuotųsi naujai įrengtose skersinėse drenažo tranšėjose. Tokios technologijos taikymas leistų padidinti sausinimo efektyvumą nekeičiant jau paklotų drenažo vamzdžių. Modeliuojant skersinių drenažo tranšėjų tankio įtaką vandens lygiui tarpdrenyje, nustatyta, kad papildomas jų įrengimas turi įtakos gruntinio vandens lygiams tarpdrenyje tik esant atstumui iki 30 m. Esant didesniam atstumui, jų poveikis gruntinio vandens lygio nuslūgimui tampa nežymus, siekia vos 1-2%. Didžiausią įtaką gruntinio vandens slūgimui tarpdrenyje turėjo skersinės drenažo tranšėjos įrengiamos 20 m tarpais, kai drenažo tranšėjos užpildo... [toliau žr. visą tekstą] / After rainfall, part of it is absorbed by the ground whereas the rest part flows upon the direction of the inclination towards the lowest points on the relief. Intensity of absorption depends on conductivity of the ground. In the hard ground water is absorbed and enters the deeper layers of the ground with difficulty due to low conductivity of the ground. Water flows most intensely through drainage trenches and next to them. These conditions of water flow in trenches form when the ground structure alters and overloads them. The time passing by, cracks, having occurred in the drainage trench, are filled with small ground particles. It influences deterioration of ground water conductivity qualities. In order to improve water runoff from the upper soil layer, natural substances found in nature, if inserted across, above the drain, could help. Using porous substances in order to cover drainage trenches, part of the water would accumulate in newly equipped cross-section drain trenches. Applying such a technology would allow increasing the efficiency of drainage without changing the already laid drainage pipes. Modeling the influence of cross-section drainage trench density on ground water level between drains, it was determined that additional installation could affect ground water level between the cross-section drains trench, the distance being up to 30 meters. When the distance is larger, its impact on the ground water level recession becomes insignificant and reaches only 1-2%... [to full text]

In this study, annual total phosphorus (TP) budget and dissolved inorganic nitrogen (DIN) load were constructed for Lakes Mogan and Eymir for the period of eight years from 1997 to 2004 and the period of ten years covering from 1993 to 1995 and 1997 to 2004, respectively. Lake Mogan experienced seasonal and interannual water level fluctuations. Low water level experienced in 2001 led to decrease in the in-lake TP amount whereas 2-fold increase in the in-lake DIN amount was recorded. Also, high hydraulic residence time resulted in high TP and DIN amount in the lake. Increase in hydraulic residence time was due to management of the lake level. It seems that this practice deteriorates the water quality of Lake Mogan. In Lake Eymir, sewage effluent diversion undertaken in 1995 resulted in 2-fold and 11-fold decrease in TP and DIN amounts in the lake, respectively. High biomass of carp and tench were halved through selective removal during 1998-1999. A 2.5-fold and 1.5 fold decrease in the in-lake TP and DIN amounts, respectively, were recorded after the biomanipulation. In low water level years, the in-lake TP increased and the in-lake DIN amounts were high despite the fact that TP and DIN loads via inflows were significantly low. Therefore, the results showed that the in-lake phosphorus and nitrogen amount were controlled by internal processes rather than external loading in the years with low water levels which coincided with the high hydraulic residence times.

A influência do nível d’água na deformabilidade dos materiais constituintes de pavimentos, especialmente dos subleitos, tem sido historicamente destacada; justificando, inclusive, a construção de drenos profundos. Nos projetos de drenagem de pavimentos, as oscilações de nível d’água são, frequentemente, inferidas a partir da intensidade de chuvas e do nível de equilíbrio do lençol freático. Contudo, no Brasil, são raros os estudos que relacionam as deflexões do pavimento com o nível d’água efetivamente registrado no interior dos subleitos. Para avaliar a influência da profundidade do nível d’água na sucção e na deflexão de pavimentos flexíveis, foram construídas duas pistas experimentais com pavimentos representativos de estruturas rodoviárias do sul do Brasil (base e sub-base granulares e revestimento em mistura asfáltica a quente). As pistas experimentais estão localizadas na Área de Pesquisas e Testes de Pavimentos (APTP), no Campus do Vale da UFRGS, em Porto Alegre. As oscilações do nível de lençol freático sob o pavimento foram induzidas através da variação do nível d’água em drenos profundos, construídos nas laterais das pistas experimentais. Os efeitos dos níveis d’água no nível do lençol freático e na sucção dos solos de subleito foram avaliados com auxílio de medidores de níveis de água, piezômetros e tensiômetros. Com a movimentação do nível d’água do lençol freático sob o pavimento, mediram-se deflexões para avaliar o efeito na deformabilidade elástica dos solos do subleito e seus reflexos no comportamento estrutural dos pavimentos. Ensaios em laboratório foram realizados em corpos de prova moldados a partir de blocos indeformados coletados no local das pistas experimentais. Os resultados de laboratório, da instrumentação das pistas e dos levantamentos defletométricos permitiram avaliar as relações existentes entre as variáveis: nível d’água, sucção e deflexão do pavimento, sob a ação de diferentes níveis d’água induzidos no solo através dos drenos. / The effect of groundwater level on deformability of materials used in pavements, particularly subgrades, has been confirmed along time and has justified the construction of deep drains. In projects of pavement drainage, water level oscillations are often inferred from the amount of rainfall and the balance level of the groundwater table. In Brazil, few studies have evaluated the association between pavement deflection and the effectively recorded groundwater level in the subgrade layer. To evaluate the effect of water level depth on suction and deflection of flexible pavements, two test roads were built with pavements representative of the roads in southern Brazil (granular base and subbase layers and hot-mix asphalt surface). The test roads were built in the Road Research and Test Area of the Campus do Vale, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil. The oscillations of the groundwater table under the pavement were induced by water level variations produced by deep drains built next to the test roads. The effects of variations on groundwater table level and subgrade soil suction were evaluated using water level gauges, piezometers and tensiometers. As groundwater levels moved under the pavement, deflections were measured to evaluate the effect of elastic deformations of the subgrade soil on the structural behavior of pavements. Laboratory tests were conducted with specimens prepared using non-deformed blocks collected from the site of the test roads. Laboratory tests, gauge readings and deflectometry measured the progression of water levels and suction, and the elastic vertical displacements of the test road surfaces were demonstrated. Results and analyses defined the associations of water level, soil suction and deflection with the action of different water levels induced by the action of drains.

A influência do nível d’água na deformabilidade dos materiais constituintes de pavimentos, especialmente dos subleitos, tem sido historicamente destacada; justificando, inclusive, a construção de drenos profundos. Nos projetos de drenagem de pavimentos, as oscilações de nível d’água são, frequentemente, inferidas a partir da intensidade de chuvas e do nível de equilíbrio do lençol freático. Contudo, no Brasil, são raros os estudos que relacionam as deflexões do pavimento com o nível d’água efetivamente registrado no interior dos subleitos. Para avaliar a influência da profundidade do nível d’água na sucção e na deflexão de pavimentos flexíveis, foram construídas duas pistas experimentais com pavimentos representativos de estruturas rodoviárias do sul do Brasil (base e sub-base granulares e revestimento em mistura asfáltica a quente). As pistas experimentais estão localizadas na Área de Pesquisas e Testes de Pavimentos (APTP), no Campus do Vale da UFRGS, em Porto Alegre. As oscilações do nível de lençol freático sob o pavimento foram induzidas através da variação do nível d’água em drenos profundos, construídos nas laterais das pistas experimentais. Os efeitos dos níveis d’água no nível do lençol freático e na sucção dos solos de subleito foram avaliados com auxílio de medidores de níveis de água, piezômetros e tensiômetros. Com a movimentação do nível d’água do lençol freático sob o pavimento, mediram-se deflexões para avaliar o efeito na deformabilidade elástica dos solos do subleito e seus reflexos no comportamento estrutural dos pavimentos. Ensaios em laboratório foram realizados em corpos de prova moldados a partir de blocos indeformados coletados no local das pistas experimentais. Os resultados de laboratório, da instrumentação das pistas e dos levantamentos defletométricos permitiram avaliar as relações existentes entre as variáveis: nível d’água, sucção e deflexão do pavimento, sob a ação de diferentes níveis d’água induzidos no solo através dos drenos. / The effect of groundwater level on deformability of materials used in pavements, particularly subgrades, has been confirmed along time and has justified the construction of deep drains. In projects of pavement drainage, water level oscillations are often inferred from the amount of rainfall and the balance level of the groundwater table. In Brazil, few studies have evaluated the association between pavement deflection and the effectively recorded groundwater level in the subgrade layer. To evaluate the effect of water level depth on suction and deflection of flexible pavements, two test roads were built with pavements representative of the roads in southern Brazil (granular base and subbase layers and hot-mix asphalt surface). The test roads were built in the Road Research and Test Area of the Campus do Vale, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil. The oscillations of the groundwater table under the pavement were induced by water level variations produced by deep drains built next to the test roads. The effects of variations on groundwater table level and subgrade soil suction were evaluated using water level gauges, piezometers and tensiometers. As groundwater levels moved under the pavement, deflections were measured to evaluate the effect of elastic deformations of the subgrade soil on the structural behavior of pavements. Laboratory tests were conducted with specimens prepared using non-deformed blocks collected from the site of the test roads. Laboratory tests, gauge readings and deflectometry measured the progression of water levels and suction, and the elastic vertical displacements of the test road surfaces were demonstrated. Results and analyses defined the associations of water level, soil suction and deflection with the action of different water levels induced by the action of drains.

This thesis is an extension of my Bc. thesis. Based upon previously conducted research in a wet grassland, Mokré Louky, near Třeboň, Czech Republic, a mesocosm experiment was designed for investigating the effect of two nutrient regimes (non fertilized / fertilized) and three flooding regimes (saturated / spring flood / flooded) on Carex acuta and Phalaris arundinacea plants to determine the effect of management type for restoring a more diverse wet meadows system.

A influência do nível d’água na deformabilidade dos materiais constituintes de pavimentos, especialmente dos subleitos, tem sido historicamente destacada; justificando, inclusive, a construção de drenos profundos. Nos projetos de drenagem de pavimentos, as oscilações de nível d’água são, frequentemente, inferidas a partir da intensidade de chuvas e do nível de equilíbrio do lençol freático. Contudo, no Brasil, são raros os estudos que relacionam as deflexões do pavimento com o nível d’água efetivamente registrado no interior dos subleitos. Para avaliar a influência da profundidade do nível d’água na sucção e na deflexão de pavimentos flexíveis, foram construídas duas pistas experimentais com pavimentos representativos de estruturas rodoviárias do sul do Brasil (base e sub-base granulares e revestimento em mistura asfáltica a quente). As pistas experimentais estão localizadas na Área de Pesquisas e Testes de Pavimentos (APTP), no Campus do Vale da UFRGS, em Porto Alegre. As oscilações do nível de lençol freático sob o pavimento foram induzidas através da variação do nível d’água em drenos profundos, construídos nas laterais das pistas experimentais. Os efeitos dos níveis d’água no nível do lençol freático e na sucção dos solos de subleito foram avaliados com auxílio de medidores de níveis de água, piezômetros e tensiômetros. Com a movimentação do nível d’água do lençol freático sob o pavimento, mediram-se deflexões para avaliar o efeito na deformabilidade elástica dos solos do subleito e seus reflexos no comportamento estrutural dos pavimentos. Ensaios em laboratório foram realizados em corpos de prova moldados a partir de blocos indeformados coletados no local das pistas experimentais. Os resultados de laboratório, da instrumentação das pistas e dos levantamentos defletométricos permitiram avaliar as relações existentes entre as variáveis: nível d’água, sucção e deflexão do pavimento, sob a ação de diferentes níveis d’água induzidos no solo através dos drenos. / The effect of groundwater level on deformability of materials used in pavements, particularly subgrades, has been confirmed along time and has justified the construction of deep drains. In projects of pavement drainage, water level oscillations are often inferred from the amount of rainfall and the balance level of the groundwater table. In Brazil, few studies have evaluated the association between pavement deflection and the effectively recorded groundwater level in the subgrade layer. To evaluate the effect of water level depth on suction and deflection of flexible pavements, two test roads were built with pavements representative of the roads in southern Brazil (granular base and subbase layers and hot-mix asphalt surface). The test roads were built in the Road Research and Test Area of the Campus do Vale, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil. The oscillations of the groundwater table under the pavement were induced by water level variations produced by deep drains built next to the test roads. The effects of variations on groundwater table level and subgrade soil suction were evaluated using water level gauges, piezometers and tensiometers. As groundwater levels moved under the pavement, deflections were measured to evaluate the effect of elastic deformations of the subgrade soil on the structural behavior of pavements. Laboratory tests were conducted with specimens prepared using non-deformed blocks collected from the site of the test roads. Laboratory tests, gauge readings and deflectometry measured the progression of water levels and suction, and the elastic vertical displacements of the test road surfaces were demonstrated. Results and analyses defined the associations of water level, soil suction and deflection with the action of different water levels induced by the action of drains.

Submitted by (lucia.rodrigues@ufrpe.br) on 2016-10-13T12:29:24Z No. of bitstreams: 1 Robertson Valerio de Paiva Fontes Junior.pdf: 4387558 bytes, checksum: c342763c06f5209dd874a07bffd3690c (MD5) / Made available in DSpace on 2016-10-13T12:29:24Z (GMT). No. of bitstreams: 1 Robertson Valerio de Paiva Fontes Junior.pdf: 4387558 bytes, checksum: c342763c06f5209dd874a07bffd3690c (MD5) Previous issue date: 2012-02-28 / The Brazilian Northeast is subject to repeated events of drought and rainfall distribution in time is very irregular, and hence the use water resources is limited. These restrictions are due to rainfall concentrated in a short period of time, with most being lost by runoff and evaporation. The alluvial aquifers, although limited in space, has considerable water reserves understanding of the piezometric levels and salinity behavior in relation to rainfall and its recharge are of great importance for the water resources management in semiarid regions. The present work aims to studying, analyzing and identifying representative areas for level and salinity behavior in an alluvial valley and its variation in time and space, as well as the behavior of recharge through the daily water balance model BALSEQ_MOD to Mimoso Basin which is located in Pesqueira, Brazil. Two piezometers were found stable for the average behavior of the water table and two piezometers to electrical conductivity, and the stable level presented correlation with the behavior of the valley, while electrical conductivity was not stable. In the evaluation of its temporal variability the piezometers with stable level showed ranges of 7-8 months, while the electrical conductivity for piezometers showed a pure nugget effect and the other a range of 2 months. Simulations applying the BALSEQ_MOD showed the strong influence of actual evapotranspiration (ETR) in the behavior of recharge and runoff is highly variable over time for the basin and the alluvial valley. / O Nordeste Brasileiro está sujeito a repetidos eventos de veranico e a distribuição das chuvas no tempo é bastante irregular, tornando o uso dos recursos hídricos restrito. Estas restrições se devem a chuvas concentradas em um curto período de tempo, sendo a maior parte perdido por escoamento superficial e evaporação. Os aquíferos aluvionares apesar de limitados no espaço possuem considerável reserva de água e a compreensão dos comportamentos dos níveis piezométricos e da salinidade em relação às chuvas e sua recarga é de grande importância para a gestão dos recursos hídricos nas regiões semiáridas. O presente trabalho tem como objetivo avaliar áreas representativas para o nível e salinidade no vale aluvial e seu comportamento no tempo e espaço e o comportamento da recarga através do modelo de balanço hídrico diário BALSEQ_MOD, na Bacia Hidrográfica do Riacho Mimoso, que está localizada no município de Pesqueira, Brasil. Foram encontrados dois piezômetros estáveis para o comportamento médio do nível freático e dois piezômetros para a condutividade elétrica, sendo que os estáveis para nível apresentaram correlação com o comportamento do vale, enquanto os de condutividade não. Na avaliação das suas variabilidades temporais os piezômetros para nível apresentaram alcances de 7 a 8 meses; os piezômetros para condutividade elétrica, um deles apresentou efeito pepita puro e o outro um alcance de 2 meses. Os dados simulados no BALSEQ_MOD mostraram a forte influência da evapotranspiração real (ETR) no comportamento da recarga e que o escoamento é muito variável ao longo do tempo para a bacia e para o vale aluvial.

Die Grundwasserstände unterliegen in den Gebieten des Braunkohlenbergbaus permanenter, bergbaulich bedingter Veränderung. Im Einflussbereich der aktiven Braunkohlentagebaue überwiegen sinkende - im Bereich der ehemaligen Tagebaubereiche nach Einstellung der Wasserhaltungsmaßnahmen dagegen steigende Grundwasserstände. Der Grundwasserwiederanstieg im Verantwortungsbereich der LMBV mbH ist schon weit vorangeschritten aber noch nicht überall abgeschlossen. Im Zuge der Auswertung von regelmäßig durchgeführten Präzisionsnivellements wurden in den gewachsenen Randbereichen der in Flutung befindlichen Tagebauseen Hebungen festgestellt, die in ihrer räumlichen Ausdehnung und dem Betrag mit den Ergebnissen der Beobachtungen der Grundwasserstände korrelieren. Rückblickend werden die Zusammenhänge zwischen Grundwasserwiederanstieg und Hebungen des gewachsenen Bodens anhand von Beispielen von bereits gefluteten Tagebauseen aus dem Mitteldeutschen Braunkohlenrevier betrachtet. Die festgestellten Hebungen vollziehen sich längerfristig über mehrere Jahre. Die Hebungsbeträge erreichen maximale Werte von einigen Zentimetern - erreichen aber nicht die Beträge der früheren sümpfungsbedingten Senkungen. Schädliche Auswirkungen auf Bauwerke durch grundwasserwiederanstiegsbedingte Hebungen waren nicht zu erwarten und sind auch nicht eingetreten. / Water tables in lignite mining areas are characterized by a permanent mining-related variation. In the sphere of influence of the active lignite mines preponderates decreasing – in reach of the abandoned lignite mining areas in contrast increasing water tables. The groundwater resurgence within the areas of responsibility of LMBV mbH is widely pro-ceeded but yet not completed in all areas. In the course of the evaluation of regularly conducted precision levellings uplifts were detected in the natural boundary areas of post-mining lakes still in flooding progress. These uplifts correlate in their regional/areal dimension and magnitude with the results of the water tables. The coherence between groundwater resurgence and the uplifts will be examined retrospectively based on examples of flooded post-mining lakes from the mining area around the cities of Leipzig and Halle. The observed elevation take place over some years. The elevation amount reaches maximum values of a few centimeters, but doesn’t reach the amount of the former drainage caused subsidence. Adverse effects on buildings by groundwater resurgence caused elevation were not expected and didn’t occur so far.

Philosophiae Doctor - PhD / In this thesis, I examine household strategies in response to water level fluctuations of Lake Chilwa. I also analyse the frequency and patterns of migration of fishers, conflicts due to migration of fishers and comanagement. The following are the key results:First, the seasonal and periodic lake level changes affect livelihoods of the households. As a coping strategy, the households depend on fishing in pools of water located in influent rivers and hunt birds for income and food while others migrate to find work as casual labourers. When the lake rises during the rain season, inundated areas become suitable for production of maize and rice. However, when the floods recede in the dry season, farming of winter maize and vegetables is common.Second, migration of fishers is common around Lake Chilwa. The pattern of migration varies according to the season and gear type. The northern marshes and floodplain where fishers land the highest catches composed mainly of Barbus paludinosus, attract more fishers operating different fishing gear types. Conflicts emerge due to the Nkacha seine operations,which require removal of aquatic vegetation. The local fishers believe that the aquatic vegetation is a source of food for fish. The conflicts are in various forms including access to fishing grounds, authority to grant access to fishing areas and fish price competition between the local fishers and migrants.Third, the household strategies towards recovery of the fishery after recessions are inherent within the households’ traditional system.However, the introduction of co-management does not recognise key actors that include fishers and river-based fishing households that participated in the formulation of conservation strategies for remnant fish stocks in lagoon and rivers during the 1995 recession. Co-management is characterised by limited participation of the fishers especially those operating seines, district assemblies and non-governmental organisations. Similarly, there is low transparency especially with respect to how the key stakeholders, Department of Fisheries and traditional leaders, take decisions. In stark contrast, accountability among Beach Village Sub- Committees is growing; hence more fishing households now perceive these as representing the interests of Department of Fisheries.Based on the above results, a diversified occupational change involving fishing, farming and trading is necessary. The co-management arrangement should be adaptive with consideration of the traditional customs and values of the participating households. Since these households are dependent on the availability of fisheries, it is thus imperative to promote maximum resource exploitation in between recessions and encourage a complete stop to fishing during recessions.September 2009

Scientific evidence points to a changing global climate. The most vital and visible impacts of this phenomenon for sea-level communities are sea-level rise, coastal erosion, and more frequent severe coastal storms. However, limited research has been conducted to date to project the damage from rising maximum water levels and corresponding storm surges, and their impacts on the sustainability of coastal communities. This research focuses on the urban coastal community of Charlottetown, Prince Edward Island (P.E.I.), Canada as part of the C-Change International Community University research Alliance (ICURA), “Managing Adaptation to Environmental Change in Coastal Communities: Canada and the Caribbean.” The stochastic process that underlies, maximum observed water levels in Charlottetown, is modeled using historical data. Maximum observed water levels and storm surges are represented by fitted conditional and marginal univariate probability density functions. The statistical package “Easy-Fit” is used as a tool for analyzing goodness of fit to the historical data for maximum observed water levels in Charlottetown. A System Dynamics (SD) model, using STELLA, is developed to simulate the projected impacts of maximum observed water levels on the City of Charlottetown. The SD model captures the dynamics of the four pillars of community sustainability, namely Environmental, Economic, Social-Cultural and Human sectors identified for the City of Charlottetown. The model defines and evaluates the robustness of alternative adaptation strategies for various model scenarios to projected storms over a long-term planning period. The results quantify the vulnerability of Charlottetown. The analysis of the results from implementing 3 main adaptation strategies for protection, accommodation, and retreat scenarios as well as the ones from the most common current response of “doing nothing”, provide information on the dynamic and pillar-related impacts of storms on Charlottetown. Analysis of these strategy options clearly indicates that doing nothing in the face of more frequent severe storms is an inefficient strategy. Model results show that the protect strategy is unlikely to deliver complete protection, and the retreat option is costly and not well received. The accommodation strategy including a combination of protection options and controlled retreat will provide the most robust option for the coastal City of Charlottetown. The SD model and analysis provides a framework for the evaluation of adaptation strategies for alternative coastal communities.