Developing hydrological model for water quality in Iraq marshes zone by using geographic information system and remote sensing

The mesopotamia marshlands constitute the largest wetland ecosystem in the middle east and western Eurasia, These marshlands are located at the confluence of Tigris and Euphrates rivers in southern Iraq, The construction dams by Turkish and Syrian for water storage as well as hydroelectric power generation along the Euphrates and Tigris rivers are led to reduce and deterioration water quality in Iraq's marshes, Moreover the first gulf war in 1980 and 1991 then 2003 wars on Iraq these led to deterioration and damaged majority of the marshes resources, In fact the marshes had been reduced in size to less than 7% since 1973 and had deteriorated in water quality parameters, The objective of this study to develop a new algorithm to retrieve water quality from Landsat-7 (TM and ETM) data based on differential equations algorithm. Moreover To derive two dimensional hydrodynamic effects on water quality patterns and trajectory movement of water quality distribution depending on finite element model such as two-dimensional depth averaged finite element hydrodynamic numerical model of resource management associates (FENM-RMA 2) and finite element water quality transport numerical model of resource management associates (FENM-RMA4) then using geographic information system to map hydrodynamic and the spatial variation of water quality parameters concentrations for total dissolved solids (TDS), total suspended solids (TSS) and salinity within Iraq's marshes in series time of different years

Modelação de pradarias marinhas intertidais numa laguna costeira mesotidal

Seagrass meadows are important habitats of marine plants, adapted to the colonization of coastal and estuarine environments, which provide important functions within the ecosystem. The remarkable decline of seagrass meadows at regional/local (Ria de Aveiro) and global scales has presented however negative implications for the sustainability of the ecosystems where they follow this trend. In this context, the main objective of this work was to improve the present knowledge about seagrass dynamics in the Ria de Aveiro, from a multidisciplinary viewpoint (experimental data collection and treatment and numerical modelling), as well as to anticipate potential changes at the system level in these communities. Therefore, it is intended to contribute to the promotion of adequate management and conservation strategies to minimize its decline and enhance its recovery. From the application of a conceptual DSPIR framework (Drivers-Pressures-State-Impacts- Responses), the results pointed that gradual changes in hydrodynamic characteristics are the basis of the local decline of these communities, presently colonized by monospecific intertidal meadows of Zostera noltei. The scarce availability of seagrass models is even more prominent when dealing with intertidal communities, subject to alternating periods of exposure to air and submergence. As so, the inherent peculiarities of intertidal seagrass Z. noltei communities were investigated, showing a greater influence of the sedimentary characteristics on the relative water content of the plant, rather than the air exposure time. Afterwards, it was developed a seagrass biological model together with a desiccation model of the plant, in order to suppress the previously identified gap, both of which were later coupled to the water quality model (Delft3D-WAQ). The numerical model was calibrated using experimental data collected in the study area (Mira Channel), showing a reliable reproduction of the state variables described by means of above and belowground biomass. However, the present set up needs to be improved, namely in what regards sedimentplant interface and internal nutrient dynamics, before it can be applied to other systems with similar challenges. The performance of the numerical model was analysed through different methodologies that presented divergent results, which suggests the application of further approaches for a robust conclusion. A sensitivity analysis was computed, showing that the parameters used to describe the dependence of the ambient temperature (water and air) are the most sensitive, suggesting that these should be particularly addressed in future experimental surveys, by increasing the frequency of the in situ measurements. Two exploratory simulations of extreme event, extreme river flow and heat-wave, respectively showed a decrease in the favourable conditions for seagrass presence, according to the water velocity and salinity; and clear negative impacts on seagrass growth. Following a prospective viewpoint, different evolutionary scenarios to the future, resulting from the foreseen climate change, were set according to the more and less pessimistic projection (RCP 4.5 and RCP 8.5). The numerical model projections pointed out for a noticeable loss of colonised areas by seagrass (between around 30 and 70%, respectively) compared to the present situation. The multiple stressors analysed generally showed a synergistic effect on the loss of the relative area of seagrass, compared to the isolated sum of each of the factors, which highlights the complex and intrinsic relations established between them. The areas colonized by seagrass meadows that showed greater resilience, to the two simulated climate change scenarios, are located in the south and northwest areas of the central lagoon. The spatial distribution of the anomalies between the reference and the climate change scenarios, showed no uniform pattern of variation, occurring areas with descreased favourable conditions for seagrass presence, but also some areas that verified an improvement of these conditions. For a more effective and holistic approach to the natural evolution and modelling of these systems, a wider spatial and temporal coverage of biotic and abiotic descriptors of these communities should be performed. Moreover, the overview of the ongoing and forthcoming anthropogenic actions must also be included, in the context of the socio-economic development of the region, as well as the framework of the future scenarios in the scope of climate change (temporal scale referred to the end of the century). As so, the management actions can be implemented to promote the resilience of these habitats and assure the services provided by the ecosystem.As pradarias marinhas constituem importantes habitats de plantas superiores, adaptadas à colonização de ambientes costeiros e estuarinos, que desempenham importantes funções nestes ecossistemas. O seu declínio acentuado verificado a escalas regionais/locais (Ria de Aveiro) e globais tem, no entanto, apresentado implicações nefastas para a sustentabilidade dos ecossistemas onde estão inseridas. Neste contexto, o objectivo principal deste trabalho consistiu em aprofundar o conhecimento presente da dinâmica das pradarias marinhas na Ria de Aveiro, sob o ponto de vista multidisciplinar (colheita e tratamento de dados experimentais e modelação numérica), bem como prever as potenciais alterações ao nível do sistema nestas comunidades. Desta forma, pretende-se contribuir para a promoção de estratégias de conservação adequadas para minimizar o seu declínio e potenciar a sua recuperação. Partindo da aplicação de um modelo conceptual DPSIR (Drivers-Pressures- State-Impacts-Responses), concluiu-se que as alterações graduais nas características hidrodinâmicas estão na base do declínio local destas comunidades, presentemente colonizadas por pradarias monoespecíficas intertidais de Zostera noltei. A escassez de modelos numéricos de pradaria é acentuada, sendo ainda mais proeminente quando se tratam de comunidades intertidais, sujeitas a períodos alternados de exposição ao ar e submersão. Desta forma, as particularidades inerentes às comunidades de pradarias intertidais foram investigadas, mostrando maior influência das características sedimentares no teor relativo de água da planta, em detrimento do tempo de exposição ao ar. Posteriormente, foi desenvolvido um modelo biológico de pradaria, juntamente com um modelo de dessecação da planta, com vista a suprimir a lacuna previamente identificada, sendo ambos posteriormente acoplados ao modelo de qualidade da água (Delft3D-WAQ). Utilizando os dados experimentais colhidos na área de estudo (Canal de Mira) calibrou-se o modelo numérico, tendo-se verificado uma reprodução fiável das variáveis-estado descritas pela biomassa aérea e subterrânea. Porém, a presente configuração requer melhorias adicionais, nomeadamente no que respeita à interface sedimento-planta e dinâmica interna de nutrientes, previamente a ser passível de ser aplicado a outros sistemas com desafios semelhantes. O desempenho do modelo numérico foi analisado por diferentes metodologias que apresentaram resultados divergentes, o que sugere a necessidade de desenvolvimento e aplicação de metodologias adicionais para uma conclusão robusta. Foi realizada uma análise de sensibilidade, que permitiu aferir que os parâmetros usados para descrever a dependência da temperatura ambiente (água e ar) são os mais sensíveis. Deste modo, salienta-se a sua potencial importância e sugere-se a sua consideração em planeamentos experimentais futuros com maior frequência de amostragem nas medições in situ. Numa abordagem exploratória, simularam-se dois eventos extremos, caudal fluvial extremo e onda de calor, tendo os resultados apresentado, respectivamente, uma diminuição das condições favoráveis para a presença de pradarias em termos de velocidade da corrente e salinidade, e um claro decréscimo no crescimento da planta. Seguindo uma abordagem prospectiva, estabeleceram-se diferentes cenários evolutivos para o futuro, resultantes das expectáveis alterações climáticas, de acordo com a projecção mais e menos pessimista (RCP 4.5 e RCP 8.5). As previsões numéricas obtidas indicam uma perda acentuada de áreas colonizadas por pradarias marinhas (entre aproximadamente 30 e 70%, respectivamente) comparativamente à situação presente. As áreas colonizadas por pradarias que mostraram uma maior resiliência, nos dois cenários de alterações climáticas, situam-se na zona sul e noroeste da laguna central. Na análise espacial da anomalia entre o cenário de referência e de alterações climáticas, não se verificou um padrão uniforme, havendo áreas que apresentam um decréscimo nas condições favoráveis para a presença de pradarias marinhas, simultaneamente à ocorrência de áreas que apontam para um melhoramento das mesmas condições. Para uma abordagem mais efectiva e holística da evolução natural e modelação destes sistemas, deve considerar-se uma maior cobertura espacial e temporal dos descritores bióticos e abióticos destas comunidades. Deve ser ainda incluído o levantamento das actividades antropogénicas decorrentes e previstas no contexto do desenvolvimento socio-económico da região (escala temporal até meio do século), e ainda, deve ser feito o enquadramento nos cenários futuros no contexto das alterações climáticas (escala temporal até final do século), para que medidas de gestão possam ser implementadas no sentido de promover a resiliência destes habitats, de forma a garantir os serviços prestados.Projecto LAGOONS – FP7/2007-2013; Projecto AquiMap (MAR-02.01.01-FEAMP-0022)Programa Doutoral em Biologi

Modeling the impacts of pulsed riverine inflows on hydrodynamics and water quality in the Barataria Bay estuary

Eutrophication and coastal wetland loss are the major environmental problems affecting estuaries around the world. In Louisiana, controlled diversions of the Mississippi River water back into coastal wetlands are thought to be an important engineering solution that could reverse coastal land loss. There are concerns, however, that freshwater diversions may increase nutrient inputs and create severe eutrophication problems in estuaries and wetlands adjacent to the diversion sites. My dissertation research concerns modeling the effects of the observed and hypothetical freshwater diversion discharges on the hydrodynamics, salinity and water quality in the Barataria estuary, a deltaic estuary in south Louisiana. This estuary receives freshwater and nutrient discharges from the Davis Pond diversion, the world’s largest freshwater diversion project. I have implemented two Barataria Bay simulation models of differing complexity, a simple 6-box mass-balance model and a high resolution two-dimensional (2-D) coupled hydrology-hydrodynamic- water quality model. Model results have shown that the Barataria estuary imports nitrogen and exports carbon to the coastal ocean. Compared to the lower Mississippi River, the Barataria estuary appears to be a very small source of total organic carbon for the northern Gulf of Mexico and is unlikely to have a significant influence on the development of the Gulf’s hypoxia. Model simulations pointed out that the effects of different diversion discharges on salinity are most apparent in the middle and lower sections of the Barataria estuary. Further, tracer simulation experiments have shown that residence times differ markedly at different locations within the same water body due to differences in small scale hydrodynamics. Model simulations clearly demonstrated the importance of residence times for the overall functioning of the estuary. Model simulations also pointed out the differences in spatial patterns in phytoplankton response to distributed freshwater and nutrient inflows, reflecting the near-field control of nutrients and far-field control of residence times on phytoplankton standing stock. The models reiterate the fact that there are significant tradeoffs in using freshwater diversions in coastal restoration efforts, namely tradeoffs between hydrologic restoration and water quality effects

Hydrodynamics and Sediment Transport Studies in Tidal Marshes of the Delaware Bay using High Resolution Numerical Models

This thesis presents the development work of high resolution 2-dimensional hydro- and morphodynamic numerical models of the Blackbird Creek and Bombay Hook marshes in the Delaware Bay. The goal was to assess the models ability of representing the complex marsh hydrodynamics, to study sediment transport in marshes and exchange processes between marshes and the adjacent bay and to better understand the sensitivity of these complex ecosystems to changes in the bay environment.A high resolution numerical mesh was required to resolve the complex marsh geometry in sufficient detail for the studies. An approach was chosen that mostly employed existing data and only a minimum of additional field surveys. Methods were developed to improve the accuracy of bare ground elevations on vegetated tidal flats and to prepare bathymetry data for tidal channels based on a small number of cross sectional measurements.The model system MARINA2D was tested and validated with the Delaware Bay Model Evaluation Environment from NOAA. Model results of water levels in marshes also showed good agreement with observed data for the Bombay Hook model, yet low water was under predicted in the Blackbird Creek model, likely as a result of higher vertical errors in its initial bathymetry and topography. The Blackbird Creek model was used to assess the models' performance with respect to water levels and velocities. Analysis of the influence of vegetation on erosion and depositions patterns on tidal flats showed that in order to reproduce realistic conditions vegetation needed to be considered in the model forcing. Furthermore, for development of numerical models for marshes, additional modifications were required to correctly represent shallow flow conditions on tidal flats. Scenarios with high, medium, and low suspended sediment concentrations in the Delaware River identified the sensitivity of sediment budgets in the marsh to sources in the river.Tracer studies based on hydrodynamic simulations of the Bombay Hook marsh were performed to identify the system's sensitivity to changes in tidal channel geometry and to find the best location for a channel blockage to prevent sediment transport out of the marsh interior that increasingly suffers from losses. The results showed that the system reacts significantly to small changes in channel geometry. Analysis of three blockage scenarios provided enough information to reveal a possible solution for the marsh loss problem, highlighting the benefit of numerical studies as a tool for decision making in marsh management.Ph.D., Civil Engineering -- Drexel University, 201

Tracer and Timescale Methods for Passive and Reactive Transport in Fluid Flows

Geophysical, environmental, and urban fluid flows (i.e., flows developing in oceans, seas, estuaries, rivers, aquifers, reservoirs, etc.) exhibit a wide range of reactive and transport processes. Therefore, identifying key phenomena, understanding their relative importance, and establishing causal relationships between them is no trivial task. Analysis of primitive variables (e.g., velocity components, pressure, temperature, concentration) is not always conducive to the most fruitful interpretations. Examining auxiliary variables introduced for diagnostic purposes is an option worth considering. In this respect, tracer and timescale methods are proving to be very effective. Such methods can help address questions such as, "where does a fluid-born dissolved or particulate substance come from and where will it go?" or, "how fast are the transport and reaction phenomena controlling the appearance and disappearance such substances?" These issues have been dealt with since the 19th century, essentially by means of ad hoc approaches. However, over the past three decades, methods resting on solid theoretical foundations have been developed, which permit the evaluation of tracer concentrations and diagnostic timescales (age, residence/exposure time, etc.) across space and time and using numerical models and field data. This book comprises research and review articles, introducing state-of-the-art diagnostic theories and their applications to domains ranging from shallow human-made reservoirs to lakes, river networks, marine domains, and subsurface flow

Landsat TM-8 data for retrieving salinity in Al Huwaizah marsh, South of Iraq

Mesopotamia marshlands constitute the largest wetland ecosystem in the Middle East and western Eurasia. These marshlands are located at the confluence of Tigris and Euphrates rivers in southern Iraq. Al-Huwaizah marsh is the biggest marsh in southern Iraq covered by an area (2400 Km2-3000 Km2) and depth (1.5 m-5 m). The construction dams by Turkey and Syrian for water storage as well as hydroelectric power generation along Tigris and Euphrates rivers, led to reduce and deteriorate water quality in Iraq's marshes. Salinity has become one of the major problems affecting crop production and food security in central and southern Iraq. The objective of this study to develop a new algorithm to retrieve salinity and normalized difference vegetation index (NDVI) from optical remote sensing Landsat-8 (OLI/TIRS) data based on differential equations algorithms. The mathematical algorithms are linear, power and exponential algorithm. The integration between remote sensing techniques and geographic information system (GIS) to map hydrodynamic and the spatial variation of salinity distribution. There is a pressing need to quantify and map the spatial extent and distribution of the salinity in Al-Huwaizah marsh of southern Iraq during March-2013. The findings of this study proved that the integration between Landsat-8 data and GIS with salinity algorithms could provide a powerful tool for retrieving salinity in marshes zone

Modelling the Eddy Pattern in the harbour of Zeebrugge

Hydrodynamic