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Rivers were always an important factor in the evolution ofcities. From ancient times, rivers were used in cities forirrigation, transportation, leisure and other activities. In the lastcouple of decades, urbanism paid special attention to therelationship between the river and the city.Bucharest makes no difference. The first settlement here wascreated along Dambovita, the only river of the city. During theyears, Dambovita faced different changes. Each historical periodinfluenced in a different way the image and the functionality ofthe river. Nowadays, as a result of the communist period, theriver is deeply disconnected from the city, being polluted andforgotten by the inhabitants.The main goal of the project is to reestablish the relationbetween the river and the city. By facilitating the transport onwater, redesigning the waterfronts and creating approachablelandscapes on both sides of the river the project allows the riverto extend into the city. The car-oriented fast-traffic roads onboth sides of the river are being transformed into pedestrianareas and bike lanes and green corridors are designed on bothsides.Furthermore, two focus areas were specifically chosen torepresent the new image of the city. These neighborhoods aredesigned in close connection to the river, facilitating watertransport and the appropriation of the inhabitant to the bluestructure. The design takes into account three main structuresin the city: The Blue Structure, The Green Structure and theSocial Structure, including these three layers at all scales.

Rivers are integral parts of Bangladesh & Bengali people’s life. The whole country is criss-crossed by more than 700 rivers including their tributaries. In other words, rivers formed this country as a delta and have been contributing to spring life to this land with agriculture, food, electricity, transportation, and tranquil beauty, creating opportunity for different occupations, and providing very comfortable moderate climate. Due to over population and urban sprawl, the current development pattern of the country is culminating in filling up wetlands, changing the course of lakes, narrowing down and in some cases killing rivers for urban development leaving great impact on environment. As a consequence, the country is being affected by frequent flood, deforestation, surge, cyclones, and rise of sea level due to global warming. The concern for introducing an adoptive sustainable architecture that interacts with rivers and water, protects environment as well as facilitates new developments has been noticed by scientists and scholars from every sector of development. This thesis will be emphasizing on establishing some unique architectural features that would especially be applicable for riverfront architectures, that leaves least impact on nature and respects the country’s tradition, heritage and lifestyle which are inseparable from rivers.

The aim of this study has been to measure some of the ecological factors in a series of plant habitats and their relation to the existing vegetation in selected twenty soil types of Red River County, Texas.

Due to the flocculation process, suspended mud aggregates carried by rivers and streams can undergo changes in their size, shape, and settling velocity in response to environmental drivers such as turbulence, sediment concentration, organic matter (OM), and salinity. Some have assumed that salt is necessary for floc formation, and that mud, therefore, reaches the estuary unflocculated. Yet mud flocs exist in freshwater systems long before the estuarine zone, likely due to the presence of OM and ions in the water that facilitate binding and aggregation of mud particles. This research aimed to examine the flocculation state of mud over the fluvial as well as fluvial to marine transition (FtMT) zones of the Mississippi River basin and how salinity, or the ion concentration of water, and organic matter independently and together affect flocculation. Suspended mud was found to be mostly flocculated in the headwaters of the Mississippi River in southwest Virginia, USA. However, increasing the ion concentration of water samples to levels measured following winter storms changed the size distribution of suspended particles, led to more of the mud existing in large flocs, and resulted in an overall increase in average size by about 40%, thereby increasing the settling rate of the mud relative to the suspensions without salt. These results suggested that potential negative effects of road salts on mud deposition should be investigated further. Additional experiments were used to examine the flocculation of a natural mud sample with and without OM showed that the rate of floc growth and equilibrium size both increase with salinity regardless of the presence or absence of OM. However, the response of both to salinity was stronger when OM was present. In deionized water, natural sediment with OM was seen to produce large flocs. However, the size distribution of the suspension tended to be bimodal. With the addition of salt, increasing amounts of unflocculated material became bound within flocs, producing a more unimodal size distribution. Here, the enhancing effects of salt were noticeable at even 0.5 ppt, and increases in salinity past 3 to 5 ppt only marginally increased the floc growth rate and final size. A salinity-dependent model to account for changes in floc growth rate and equilibrium size was presented. Laboratory experiments on the sediment suspended in the lower reaches of the Mississippi River were used to provide further insight on the mud flocs behavior in the FtMT. Turbulence shear rate, a proxy for the river hydrodynamics, was found to be the most influential factor in mud floc size. While artificial increase in salinity by adding of salts did not lead to considerable increase in floc size, addition of water collected from the Gulf of Mexico enhanced the flocculation. These effects were speculated to originate from the biomatter composition of the Gulf water, particularly where the nutrient-rich Mississippi River water reaches the marine water. / Doctor of Philosophy / Rivers bring a substantial amount of mud to coastal regions. Where this mud deposits is important in shaping the coastal land and nutrient dynamics. Mud particles are different from sand and gravel in that they can form aggregates known as flocs that constantly change shape and size under different conditions. As they change size, they change how fast they sink, and this influences where they deposit. Due to their small size, mud particles are also considered a pollutant as they can clog up fish gills and destroy freshwater habitats. Findings of this dissertation showed that the roadway deicing salts that make their way to streams can enhance the aggregation of mud particles, causing them to sink faster. This can be harmful to the species that live on streambeds. While salts are known to enhance flocculation, there is ample evidence that flocs exist in rivers before reaching the sea. It is possible, therefore, that flocs in estuaries are due to biological matter acting as a glue to bind mud particles together and may not be influenced by salt. This dissertation looked at the effects of saltwater on mud flocculation when biological matter is present and when it is absent. Findings showed that salinity increased the size of mud flocs, even more so than when organic matter was absent. However, organic matter was needed for flocs to reach sizes often found in nature. An equation was also provided to aid in the prediction of floc size under different salinities. Observations on the lower Mississippi River flocs showed that the turbulence of water was the most influential factor in determining the size of flocs.

The concept became a logical solution to the division of area into one located in safer areas before the floodwaters in the northern part and leave the lower parts of river. Boundaries of the division is backed flood protection embankment height of 1.2 meters. Existing sports facilities are left in place. North Sokol is included in the planned development area in the coming years. This development is indicated by placing more focus to the development of situational plot. As another layer to enter the Wilsons forest that surrounds the R42 highway, thus eliminating the noise in the nature of the area in question. Communication in the area is solved by the level of the main pedestrian routes, which are designed as 4 meters wide. The area is also dealt with a different approach to the river and road on the other hand, depending on location. The nature of the river becomes a silent partner in contemplation, in contrast to the early-evening sports wandering in the excitement.

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River regulation cause unnatural water flow patterns which disrupt succession, survival and dispersal of riverine plant communities. Riparian zones in regulated rivers are generally more species poor and have a lower vegetation cover compared to free-flowing rivers. Tributary mouths within the impoundment however, are not only affected by processes in the main channel, but also affected by processes such as sediment dynamics and flooding regime from the tributary which may more reflect a natural regime and may therefore not be affected by hydropeaking to the same extent. Hence, tributary sites and the accompanied tributary mouths may represent hotspots for high diversity plant communities in regulated rivers. The riparian habitat is unique in its interaction with adjacent ecological systems and is therefore considered important for the riverine ecosystem’s ecological functioning. The aim of the study was to evaluate the significance of tributary sites and accompanied tributary mouths as a hotspot for diverse plant communities in regulated rivers. Additionally, geomorphological features were analyzed to access the impact of hydropeaking in sheltered and non-sheltered tributary sites. Data was acquired from sampling sites within the Umeå and Luleå rivers, representing both tributary mouths and non-tributary mouth reaches. Inventories included presence of riparian and aquatic vascular plant species, vegetation cover and soil composition. The results indicate a less extensive impact of hydropeaking in tributary mouths compared to non-tributary mouth reaches. The tributary mouths had a higher species richness, diversity and vegetation cover when compared to that of the non-tributary mouth reaches. This supports the concept of tributary mouths being hotspots for plant diversity. Moreover, the sheltered tributary mouths had a higher species richness than the non-sheltered tributary sites, suggesting tributary shelter as a contributing counter of hydropeaking effects.

This thesis provides a mass conservation analysis of the Lower St. Johns River for the purpose of providing basis for future salinity transport modeling. The analysis provides an assessment of the continuous (CG) and discontinuous (DG) Galerkin finite element methods with respect to their mass conservation properties. The following thesis also presents a rigorous literature review pertaining to salinity transport in the Lower St. Johns River, from which this effort generates the data used to initialize and validate numerical simulations. Two research questions are posed and studied in this thesis: can a DG-based modeling approach produce mass conservative numerical solutions; and what are the flow interactions between the river and the marshes within the coastal region of the Lower St. Johns River? Reviewing the available data provides an initial perspective of the ecosystem. For this, salinity data are obtained and assembled for three modeling scenarios. Each scenario, High Extreme, Most Variable, and Low Extreme, is 30 days long (taken from year 1999) and represents a unique salinity regime in the Lower St. Johns River. Time-series of salinity data is collected at four stations in the lower and middle reaches of the Lower St. Johns River, which provides a vantage point for assessing longitudinal variation of salinity. As an aside, precipitation and evaporation data is presented for seven stations along the entire St. Johns River, which provides added insight into salinity transport in the river. A mass conservation analysis is conducted for the Lower St. Johns River. The analysis utilizes a segmentation of the Lower St. Johns River, which divides the domain into sections iv based on physical characteristics. Mass errors are then calculated for the CG and DG finite element methods to determine mass conservative abilities. Also, the flow interactions (i.e., volume exchange) between the river and marshes are evaluated through the use of tidal prisms. The CG- and DG- finite element methods are then tested in tidal simulation performance, which the results are then compared to observed tides and tidal currents at four stations within the lower portion of the Lower St. Johns River. Since the results show that the DG model outperforms the CG model, the DG model is used in the tidally driven salinity transport simulations. Using four stations within the lower and middle part of the Lower St. Johns River, simulated and observed water levels and salinity concentrations are compared.

The Okavango River Basin (ORB) located in southern Africa is a region of highly sensitive and biodiverse ecosystems. It spans Angola, Namibia and Botswana, with the world-famous Okavango Delta located in the latter country. The ecosystems depend on the highly seasonal ORB streamflow, which is also the major source of freshwater for the rural population, most of whom depend on subsistence farming. Climate variability and extremes such as droughts, hot days and extreme rainfall events are not well understood over this region. Also, the relationship between climate and other aspects like vegetation and river discharge are not well understood. To contribute to a better understanding of this relationship, the thesis investigated relationships between rainfall, temperature, Normalized Difference Vegetation Index (NDVI) and river discharge, and their interannual variability and trends. It was found that at monthly and seasonal time scales, NDVI spatial patterns are closely related to those of rainfall than temperature. The NDVI-rainfall and NDVI-temperature relationships differ north of 18.9°S where rainfall is higher than to its south. Correlations between NDVI and rainfall show lags of 1-2-months. Large areas across the region show significant warming trends in all seasons but mainly in October-December (OND), as well as wetting mainly in the north. The warming trend may imply more evaporation and desiccation which may exacerbate extreme event impacts such as severe droughts. Interannual variability of rainfall, NDVI and temperature is pronounced with significant correlations with El Niño-Southern Oscillation (ENSO), the subtropical Indian Ocean Dipole (SIOD) and the Botswana High for rainfall and temperature, and for NDVI with ENSO. The temperature (rainfall) correlations with ENSO and the Botswana were positive (negative), with the SIOD they were negative (positive), and the NDVI-ENSO correlations were negative. On longer time scales, the wet 2006-2013 period was analysed relative to much drier 1999-2005 epoch for OND. The 2006-2013 wetter conditions appear linked to La Niña Modoki conditions, regional circulation differences and warmer sea surface temperature near Angola. Extreme rainfall events over the ORB were analysed. The analysis was performed within a larger region in western central southern Africa (WCSA), given that many rainfall events extend beyond river basin boundaries. Focus was placed on extreme rainfall events accumulated over 1-day (DP1) and 3-days (DP3), during the main rainy season, January-April (JFMA). Due to data sparsity, the Climate Hazards Group Infrared Precipitation with Station data (CHIRPS) were used to identify these events. It was found that contributions of DP1 and DP3 events to JFMA rainfall totals are, on average, ~10% and ~17%, respectively, but in some years their contributions exceed 30%. Most of the events result from tropical-extratropical cloud bands, with tropical lows being also important. Interannual variability in extreme events is substantial and appears linked to ENSO and the Botswana High. Although ENSO influences the extreme events and rainfall totals more generally over southern Africa, by far the neutral JFMA 2017 season experienced the wettest conditions over the world-famous Okavango Delta region. Factors that contributed to these heavy rains included a deeper Angola Low, weaker mid-level Botswana High and anomalous westerly moisture fluxes from the tropical southeast Atlantic during January – early March. The second most intense rainfall event occurred on April 22nd, resulting from a cut-off low. DP1 frequencies show significant increasing trends, and similarly, rain-days and rain totals over many areas. These trends have important implications for agricultural and water management as well as wildlife conservation in the ORB. To contribute to a better understanding of drought over the ORB region, the thesis analysed various drought metrics. These include a Cumulative Drought Intensity (CDI) index, based on the product of maximum dry spell duration and maximum temperature anomaly, and the Standardised Precipitation-Evapotranspiration Index (SPEI). Strong horizontal gradients in frequencies of dry spells and hot days were found to shift south over the ORB from August to November as the tropical rain-belt shifts increasingly south of the equator, the Congo Air Boundary declines and the Botswana High strengthens and shifts south-westwards. By December, the tropical gradient in dry spell frequencies is unnoticeable while that across the Limpopo River and southern ORB region, where the Botswana High is centred, stands out. On seasonal time scales, October-November 2013-2021 is particularly hot and dry over the Okavango Delta region. The thesis provided evidence that this hot and dry epoch is related to a stronger and southward shifted Botswana High and reduced low-level moisture convergence. On interannual time scales, there were strong relationships with the Botswana High, and to lesser extent ENSO. A strong drying-warming trend was found in the early summer, linked to a significant strengthening of the Botswana High. These trends, in conjunction with the Coupled Model Intercomparison Project Phase 6 (CMIP6) projected early summer drying over southern Africa found in the literature, may impact severely on the sensitive ecosystems of the ORB, and on water availability as well as subsistence farming in the region.