A resource assessment of the hydrokinetic potential in Canada's rivers was completed. The main objectives of the study were to (1) quantify the potential hydrokinetic energy avail- able for development both nationally and regionally, and (2) develop geospatial datasets identifying streams or areas of high hydrokinetic potential. Flow estimates at ungauged locations were found using multiple linear regression coupled with Canonical correlation analysis (MLR-CCA). Total theoretical hydro power, equivalent to total theoretical hydroki- netic power was calculated using these ow estimates and hydraulic head estimates from DEMs. It is estimated that there are 710 GW of potential power in Canadian rivers, with 97.5% con dence that there is at least 433 GW. Downstream hydraulic geometry (DHG) relations were applied to ow estimates to nd cross section velocity and power at ungauged locations. Further testing was done on DHG relations, and were found to be most accurate when characterized by soil drainage characteristics.

The thesis consist of two parts - a creative part and a written report.The creative part is a picture book about rivers and the plentiful connections they have with The creative part is a picture book about rivers and the plentiful connections they have with us humans. It follows a child and her grandma as they look for answers to a question – what is a river? In their imaginary expedition, they discover rivers flowing in the sky and in living organisms; meet pilgrims and conquistadores, magical shape-shifting river dolphins and older-than-dinosaurs species of sturgeons; fish and bathe; gathering all the stories they participate in into their own story about the river. The book combines factual infor­mation, various stories from riverine environments as well as more loose associations and metaphors. The themes I touch upon include folklore, myths, daily needs of people rivers cater to, cultural metaphors, environmental problems, peculiarities of plants and animals, history, language etc. Every spread of the book is like a different chapter about different meanings rivers might have in different contexts. The book tells about a river as a journey, home, a refreshment, a name, a meeting place, a riddle, memory, depth, energy, a reflection, a path, the ocean; and as a thread that connects stories of different times and places. To make my book, I used a variety of materials, including pencils, watercolours, gouache, digital drawing; and a collection of geographical, historical, mythological references I have gathered as well as my own memories of growing up close to a river. I have tried to balance both factually accurate and poetic storytelling to create a story of interconnectedness and wonder. The key questions I worked with were: how to tell a story about natural environment in an engaging way; how to find a narrative structure that would communicate my story effectively and would have its inner logic; how to deal with issues of historical consciousness, ecological awareness, management of natural resources in a context of children’s books; how to encourage readers to think about relations of their physical and emotional environemnts. The title of the book is What Is a River? . It is supposed to be for children, but also for adults who would find the subject interesting. The report analyses the background, processes, and results of making the book.

The Greenland and Antarctic ice sheets are losing mass and contributing to global sea-level rise. Ice shelves, floating ice attached to the margins of the ice sheets, modulate sea-level rise by restraining ice-sheet flow out towards the oceans, but are sensitive to surface melting. The formation of surface meltwater lakes on ice shelves can trigger rapid ice-shelf collapse. However, surface meltwater also flows atop ice shelves through rivers. The impact of rivers on ice-shelf stability is unknown. Previous studies of ice-shelf hydrology hypothesize that rivers mitigate the damage-potential of lakes by removing surface water off of the ice shelf, but also suggest that rivers enhance ice-shelf fracturing by incising into areas of already thin ice. This dissertation is focused on exploring the role of rivers on ice-shelf stability using remote sensing datasets, conceptual models, and Augmented Reality (AR). Focusing on ice shelves in Greenland, I present the discovery of a new ice-shelf surface hydrology feature, an ice-shelf estuary, and demonstrate its potential to weaken ice shelves. I fully document this new process on the Petermann Ice Shelf, where flow reverses at the mouth of the Petermann Estuary. This study marks the first observation of ocean water atop an ice shelf. I also document the initiation and growth of fracturing along the estuary channel, and a history of rectilinear calving events, where icebergs calve along longitudinal rivers. Based on this analysis of the Petermann Estuary, I propose a new mechanism for damaging ice shelves: estuarine weakening. I present evidence that this process also occurs on the Ryder Ice Shelf in northwest Greenland. My analysis demonstrates that the role of rivers on ice-shelf stability depends on how the river mouth evolves. If ice-shelf waterfalls at the river mouth incise to sea level and form estuaries, flow reversal will modulate water export off the shelf and maintain the damage-potential of lakes, and estuarine weakening may lead to a new mode of ice-shelf calving. By analyzing the three-dimensional (3D) structure of the Petermann and Ryder Ice Shelves and Estuaries with remote sensing and radar data, I find that basal channels are an important driver of estuary development as they dictate the linearity of surface rivers. Determining the role that basal channels play in estuary formation requires accurate and appropriate data visualization tools. I develop AR applications to visualize radar data on ice shelves, towards enabling more intuitive and sophisticated interpretation of the ice-shelf structure in 3D. Through simple conceptual modeling, I suggest that although basal channels precondition ice-shelf estuary formation, estuary formation is strongly controlled by river incision. Finally, I present a model of ice-shelf estuary formation as a function of surface and basal melting. Using this conceptual model, I predict that ice-shelf estuaries could form in Antarctica in the near future. Surface melting in Antarctica is predicted to increase in under half a century. Estuary formation in Antarctica will be accelerated by lengthening of the melt season, and estuaries may form far from the calving front if rivers intersect upstream rifts. I show that ice-shelf estuaries could evolve from ice-shelf rivers in a warming Antarctica, introducing new ice-shelf weakening mechanisms. This increases the urgency to understand and include ice-shelf estuarine processes in ice-sheet models.

>Magister Scientiae - MSc / Non-perennial rivers are characterised by a discontinuous and variable hydrological flow regime which may retreat to form isolated pools along the watercourse during prolonged dry periods. The resulting spatio-temporal variability in hydrological characteristics provides support for a variety of ecological habitats which promote species richness and biodiversity. It is well established that groundwater may offer flow supplementation to perennial river flow throughout the year as baseflow, while fewer authors have unpacked the nuances of the importance of groundwater in dynamics of water persistence and the conditions that determine non-perennial pool reoccurrence. This study explores river-aquifer interaction of the Verlorenvlei catchment within the Western Cape Province of South Africa as a case study in order to create an improved hydrogeological understanding of groundwater’s role in non-perennial rivers to improve of water management practices. A multi-method approach was designed to fulfil this aim. In addition to desktop literature review and in-field sampling of water for environmental tracers, a water presence, groundwater level, and geophysical survey was conducted in order to develop a conceptual understanding of the multi-scale interaction occurring within the Verlorenvlei basin. Results of the isotopic and chemical analysis of water sources revealed the water origin and groundwater flow dynamics for the Verlorenvlei. The contribution of groundwater from Table Mountain Group related, fault-driven flow to the groundwater balance of the Verlorenvlei creates regional gaining conditions. Local gaining conditions within the Verlorenvlei river are created through lateral input of upwelling groundwater which moves downgradient with the topography as evidenced by the hydrogeological and geophysical survey. Using the Verlorenvlei as a case study, a contribution is made to the knowledge of the role of groundwater in non-perennial rivers. The results presented in this study indicate that where basin hydrogeology allows, groundwater may play an important role in the supply of water to non-perennial pools, especially during periods of minimal rainfall. The interaction mechanisms of this groundwater contribution within non-perennial rivers are site specific and spatially variable. Basin hydrogeology, subsurface stratigraphy and water availability are key limiting factors to interaction in non-perennial rivers. Future research aimed at generating robust information on discrete zones of water presence along non-perennial rivers may allow for better assessment of the potential vulnerability of these areas to water loss. Where these areas are fed by groundwater, to accommodate for their vulnerability, groundwater capture maps may allow for investigation of the local impact of groundwater use on these areas.

White Bass Morone chrysops is a native, migratory sportfish that is found throughout the central United States in large rivers and riverine impoundments. White Bass migrate into tributaries and riverine portions of reservoirs to spawn during spring. These spawning migrations concentrate fish and may make them more susceptible to angling pressure. White Bass have been well studied in reservoirs throughout the central United States since the early 2000’s when fisheries management practices shifted from population management to fish assemblage management. However, despite the increase in White Bass research in reservoirs, large river populations remain understudied. My thesis research used otolith microchemistry to assess the role of tributaries in supporting White Bass populations in the Ohio, Wabash, Middle Mississippi, Upper Mississippi and Illinois rivers and to compare population demographics (recruitment, growth, and mortality) among rivers. Water samples were collected from each of the five rivers and their tributaries and analyzed for strontium, barium, and calcium concentrations to calculate molar elemental ratios (Sr:Ca, Ba:Ca) and determine if differences in water Sr:Ca and Ba:Ca observed in prior studies persisted among large rivers and their tributaries. Otoliths from White Bass collected from locations where their movement was constrained (e.g., impoundments where dam passage is not possible) were analyzed to characterize relationships between water chemistry (Sr:Ca and Ba:Ca) and White Bass otolith chemistry. I then applied these regression relationships in conjunction with water chemistry data from each of the five large rivers and tributaries in the study area to estimate ranges of otolith Sr:Ca and Ba:Ca for White Bass in each of the rivers and tributaries. Otolith core Sr:Ca and Ba:Ca from White Bass collected from the Ohio, Wabash, Middle Mississippi, Upper Mississippi, and Illinois rivers were compared with predicted river-specific ranges of otolith Sr:Ca and Ba:Ca to identify natal river for each fish. All fish utilized for microchemistry were aged and used to create an age-at-length key from which vital rate parameters were calculated. Microchemistry results indicated that White Bass origin proportions differed among rivers. In rivers with more prominent differences in water Sr:Ca compared to their tributaries and upstream river segments, natal river assignments were more definitive and indicated that large river White Bass stocks are being strongly supplemented by tributaries and other upriver locations. In areas with small differences in water chemistry among potential natal rivers, origin designations were less definitive due to partially overlapping ranges of Sr:Ca and Ba:Ca among locations. A study using genetics to assess natal river fidelity in spawning White Bass should be conducted to better assess stocks and population structure in the large rivers. White Bass populations were dominated by age 0 fish (young of the year). Vital rate parameters were consistent with those of reservoir populations in the central United States, with riverine White Bass exhibiting fast growth, high mortality, and variable recruitment. My results indicated that a holistic approach to large river management should be considered when managing White Bass. Management regulations should reflect those in well studied reservoir populations based upon my findings, but future projects should expand upon our data and focus on population modeling of White Bass in these systems to better understand fishing and natural mortality, especially in areas of concentrated fish during the spawning season.

The cycling of nutrients is a fundamental process in streams and rivers, and scientists are increasingly recognizing the importance of animal communities to nutrient dynamics in these ecosystems. Despite growing evidence that animal excretion (i.e. urine) can supply limiting nutrients to primary producers in small streams, the importance of excretion is uncertain in large rivers. Accordingly, I used three estimation approaches based on past and new excretion rate data to determine nitrogen (N) and phosphorus (P) excretion inputs from insect communities in four large rivers (discharge > 10 cubic meters per second) in North America, and I compared these rates to both the total demand for nutrients by primary producers and background nutrient levels. Additionally, I compared the ratio of excreted nutrients (N:P) to water nutrient limitation (N-limitation or P-limitation) to understand whether excretion by insects could serve as a potential source of limited nutrients to free-floating primary producers in large river ecosystems. Across all three estimation approaches, total insect community N excretion rates ranged from 18.9 to 1070.1 μg N m-2 hr-1, while community P excretion rates ranged from 16.3 to 378.7 μg P m-2 hr-1. Across all rivers and estimation approaches, community N and P excretion was equal to 0.7 to 32.4% and 0.1 to 6.0% of total N and P demand, respectively. Additionally, excreted N and P was equivalent to 0.5 to 62.3% and 0.2 to 5.5% of background N and P levels, respectively. Excreted N:P ratios suggested that excretion may serve as an important pathway in the alleviation of nutrient limitation for some primary producers in large rivers, although additional research will be required. Compared to smaller stream ecosystems, in which animal excretion can supply >50% of total N demand, and also match > 100% of background N levels, insect excretion appears to play a smaller role in nutrient dynamics of large rivers, although excretion may contribute significantly in rivers with high animal biomass and low background nutrient levels, as for N in the North Platte River in this study.

The purpose of this research was to examine the relationship of two approaches to visual assessment of landscape--the qualitative descriptive inventory and the theoretically-based empirical perceptual preference approach. Three levels of landscape visual units based on bio-physical similarities (landscape units, setting units, and waterscape units) were identified in a marsh (CUtler Reservoir, Cache County , Utah), and its tributary streams. Color slide photographs were taken from five of the visual units. These slides were rated on a 5- point scale by panels of judges for the expression of four perceptual variables--coherence, complexity, mystery, and legibility. The same slides were rated on a 5-point scale by 98 respondents according to their preference for each slide. The relationship of the visual units, perceptual variables, and preference was evaluated by analytical and statistical procedures. Results showed significant differences in the expression of the four perceptual variables between rivers and marshes and between setting units~ Both rivers and marshes were considered coherent when there were similarities in vegetation within the respective types; however, the strong horizontal organization of the marsh scenes necessary for coherence contrasted with the edge definition and orderliness considered necessary in rivers. Mystery was also related to similar factors in rivers and marshes (such as obscuring vegetation, particularly in the marsh) but the presence of riverbanks and bends in the river corridor had a distinct effect on mystery ratings in the river scenes . Complexity in both rivers and marshes was primarily dependent on diversity of vegetation and visual depth , but the number of different visual elements in river scenes also influenced complexity. Legibility was related to straight, enclosed and simple corridors in river images and to simple spaces with regular vegetation in marsh images. Fine textures and clear spatial definition enhanced legibility. Preference ratings were significantly different between rivers and marshes, but not between river setting units or waterscape units. River scenes received higher preference ratings than marsh scenes. Mystery , complexity, and visual depth were especially important to preference. Demographic variables of age, sex, academic major, and home state did not significantly affect preference. Statistical analysis indicated each perceptual variable was an independent predictor, and that compared to visual units, perceptual variables were more strongly related to preference.

This study measured and evaluated the relation of coastal foredune morphology to stream beach outlets, and investigated the processes associated with the stream outlet. Intermediate-size streams were studied, and defined as those that flow across the beach most of the year but have no tidal influence. Fifty-four of these streams were found along the northern Oregon coast between the Columbia River and Yaquina Bay. Crescent Lake Outlet, Saltair Creek and Daley Lake Outlet were chosen as study streams for further investigation.

Magister Philosophiae - MPhil / Microplastics (MPs) are an emerging micro-pollutant that pose a threat to the ecological integrity of freshwater rivers and wetlands. Most previous work on MPs pollution has focused on marine environments. This study aimed to investigate the spatial distribution and abundance of MPs particles in the bed sediment of a freshwater coastal lake in the Zeekoevlei Nature Reserve, Cape Town, which is fed by rivers and stormwater outlets draining a heavily urbanized environment. The first objective was to characterize the spatial distribution of MPs across the lakebed environment, in relation to possible point and non-point sources of contamination.

Thesis (Sc.D.)--Massachusetts Institute of Technology, Dept. of Civil Engineering, 1982. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Bibliography: leaves 246-250. / by Konstantine P. Georgakakos. / Sc.D.