Tesis: "Water level changes"

1

松本, 則夫 y Norio MATSUMOTO. "Regression analysis for anomalous changes of ground water level due to earthquakes". American Geophysical Union, 1992. http://hdl.handle.net/2237/16367.

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2

Jia, Yuanyuan. "Applications of Synthetic Aperture Radar Data to study Permafrost Active Layer and Wetland Water Level Changes". The Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1494339630998181.

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3

Familkhalili, Ramin. "Analytical and Numerical Modeling of Long Term Changes to Tides, Storm Surge, and Total Water Level Due to Bathymetric Changes and Surge Characteristics". PDXScholar, 2019. https://pdxscholar.library.pdx.edu/open_access_etds/5014.

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Natural and local anthropogenic changes in estuaries (e.g., sea-level rise, navigation channel construction and loss of wetlands) interact with each other and produce non-linear effects. There is also a growing recognition that tides in estuaries are not stationary. These factors together are changing the estuarine water level regime, however the implications for extreme water levels remain largely unknown. Changes over the past century in many estuaries, such as channel deepening and streamlining for navigation have significantly altered the hydrodynamics of long waves, often resulting in amplified tides (a ~85% increase in Wilmington, NC since 1900) and storm surge in estuaries. This research focuses on establishing analytical and numerical models that simulate a wide range of systems and flow conditions that combine multiple flood sources: astronomical tide, storm surge, and high river flow. To investigate the effects of estuarine bathymetry conditions (e.g., channel depth, convergence length), hurricane conditions (e.g., pressure and wind field), river discharge, and surge characteristics (e.g., time scale and amplitude and relative phase) on tide and storm surge propagation, I develop an idealized analytical model and two numerical models using Delft-3D. The Cape Fear River Estuary, NC (CFRE), and St Johns River Estuary, FL (SJRE) are used as case studies to investigate flood dynamics. The analytical approach has been compared and verified with idealized numerical models. I use data recovery, data analysis, and idealized numerical modeling of the CFRE to investigate the effects of bathymetric changes (e.g., dredging and channel modification) on tidal and storm surge characteristics over the past 130 years. Data analysis and modeling results suggest that long-term changes in tides can be used along with the tidal analysis tools to investigate changes in storm surge. Analysis indicate that tidal range in Wilmington, NC (Rkm 47) has doubled to 1.55m since the 1880s, while a much smaller increase of 0.07m observed close to the ocean in Southport (Rkm 6) since the 1920s. Further, model results suggest that the majority of long term changes in tides of this system have been caused by deepening the system from 7m to 15.5m due to dredging, rather than by changes in the coastal tides. Numerical modeling using idealized, parametric tropical cyclones suggests that the amplitude of the worst-case, CAT-5 storm surge has increased by 40-60% since the nineteenth century. Storm surges are meteorologically forced shallow water waves with time scales that overlap those of the tidal bands. Using data, I show that the surge wave can be decomposed into two sinusoidal waves. Therefore, I analytically model surge via a 3-constituent analytical tide model, where the third constituent is the dominant semi-diurnal tide and friction is linearized via Chebyshev polynomials. A constant discharge is considered to approximate fluvial effects The analytical model is used to study how surge amplitude, surge time scale, and surge-tide relative phase affect the spatial pattern of amplitude growth and decay, and how depth changes caused by channel deepening influence the magnitude of a storm surge. I use non-dimensional numbers to investigate how channel depth, surge time scale and amplitude, surge asymmetry, and relative timing of surge to tides alter the damping or amplification of surge along the estuary. The non-dimensional numbers suggest that increasing depth has similar effects as decreasing the drag coefficient. Similarly, larger time scale has an equivalent effect on tide and surge as increasing depth due to channel deepening. Analytical model results show that the extent of the surge amplification is dependent on the geometry of the estuary (e.g., depth and convergence length) and characteristics of the surge wave. Both models show that much of the alterations of water levels in estuaries is due to channel deepening for navigation purposes and that the largest temporal change occur for surges with a high surge to D2 amplitude ratio and a short time scale. Model results farther indicate that surge amplitude decays more slowly (larger e-folding) in a deeper channel for all surge time scales (12hr-72hr). Another main finding is that, due to nonlinear friction, the location of maximum change in surge wave moves landward as the channel is deepened. Thus, changes in flood risk due to channel deepening are likely spatially variable even within a single estuary. Next, I use the verified analytical model and numerical models to investigate the effects of river flow on surge wave propagation, and spatial and temporal variability of compound flooding along an estuary. To model the historic SJRE, I digitize nautical charts of SJRE to develop a numerical model. Both the numerical and analytical models are used to investigate the contribution of tide, surge, and river flow to the peak water level for historic and modern system configurations. Numerical modeling results for hurricane Irma (2017) show that maximum flood water levels have shifted landward over time and changed the relative importance of the various contributing factors in the SJRE. Deepening the shipping channel from 5.5m to 15m has reduced the impacts of river flow on peak water level, but increased the effects of tide and surge. Sensitivity studies also show that peak water level decreases landward for all river flow scenarios as channel depth increases. Model results show that the timing of peak river flow relative to the time of maximum surge causes very large changes in the amplitude of total water level, and in river flow effects at upstream locations for modern configuration than for the historic model. Changes in surge amplitudes can be interpreted by the non-dimensional friction number, which shows that depth (h), surge time scale (T=1/w), and convergence length-scale (Le) affect the damping/amplification of both tides and surge waves. Overall, this study demonstrates that a system scale alteration in local storm surge dynamics over the past century is likely to have occurred in many systems and should be considered for system management. The results of this research give the scientists and engineer a better understanding of tide, river flow, and surge interactions, and thereby contribute to an understanding of how to predict storm surges and help mitigate their destructive impacts. Future system design studies also need to consider long-term and changes of construction and development activities on storm surge risk in a broader context than has historically been the case.

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4

Dietze, Elisabeth [Verfasser]. "Water level changes and related sedimentary environments at Lake Donggi Cona, north-eastern Tibetan Plateau, China / Elisabeth Dietze". Berlin : Freie Universität Berlin, 2013. http://d-nb.info/103119021X/34.

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5

Eades, Philip Andrew. "Experimental studies into the effects of water level changes upon the vegetation and fertility of calcareous spring-fed fens". Thesis, University of Sheffield, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.268281.

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6

Gutierrez, Benjamin Thomas. "Relative sea-level rise and the development of channel-fill and shallow-water sequences on Cape Cod, Massachusetts". Thesis, Massachusetts Institute of Technology, 1999. http://hdl.handle.net/1721.1/55058.

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Thesis (M.S.)--Joint Program in Oceanography (Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences; and the Woods Hole Oceanographic Institution), 1999.
Includes bibliographical references (leaves 60-63).
Channel-fill sediments located in shallow-water off the south shore of Cape Cod, Massachusetts, provide a record of the late-Pleistocene and Holocene geological evolution in a post-glacial setting. Though conventionally difficult to sample adequately and anticipated to have low preservation potential, channel-fill sequences record in some detail differing relative sea-level and sedimentation processes. Two distinct channel-fill sequences record differing sequence stratigraphies, and hence different origins and post glacial histories. These sequences have accumulated in channels eroded into two different late-Pleistocene glacial units. The first fill-type was encountered in channels on the upper portions of the channel network in northern half of the study site. Channels in this portion of the channel system were incised into the late-Pleistocene glacial outwash substrate by spring sapping Uchupi and Oldale, 1994. The channel-fill sequences are comprised of a transgressive systems tract composed of a consistent sequence of coastal embayment and shoreline facies that have succeeded one another in response to Holocene relative sea-level rise. As relative sea-level flooded these paleo-channels, marsh environments were established in response to rising relative sea-level. With continued sea-level rise, the marsh environments migrated farther up channel. The exposed paleo-channels continued to flood, accommodating quiet water coastal embayments, likely protected from wave action by barrier beaches located more seaward. As relative sea-level rise continued, the coastline was driven landward over regions within the paleo-channels that formerly accommodated marsh and embayment sedimentation. The landward migration of the coastline was indicated by beach and barrier facies that covered the fine grained coastal embayment sediments. With further relative sea-level rise, beach and barrier settings were eroded as the shoreface migrated farther landward and nearshore marine deposition by wave and tidal flows ensued. Sedimentary environments similar to those recorded in the channels are found in modern coastal embayments on the south shore of Cape Cod. The second channel-fill type, which forms part of the southern and western portion of the channel network is more difficult to relate to the previously described sequence. The channels that contain fill were not adequately defined in this survey but were probably incised during the late-Pleistocene in response to ice melting and retreat. The sediments that make up this channel-fill are composed mainly of late-Pleistocene glaciolacustrine silts and clays. Sediments that make up the Holocene transgressive systems tract are limited to the upper meter of this channel sequence. They are composed of two sand units that reflect Holocene beach and nearshore sedimentation. The absence of coastal embayment and other paralic facies from the systems tract suggests that these channels did not accommodate protected embayments or that these sediments were not well preserved during the submergence of this region. Changes in the channel orientation or in the rate of relative sea-level rise may have contributed to this difference in sediment fill.
by Benjamin Thomas Gutierrez.
M.S.

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7

Partanen, S. (Sari). "Recent spatiotemporal changes and main determinants of aquatic macrophyte vegetation in large lakes in Finland". Doctoral thesis, University of Oulu, 2007. http://urn.fi/urn:isbn:9789514285950.

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Abstract During the past half century several large lakes in Finland have experienced notable changes in their ecological condition, induced mainly by water level regulation, eutrophication and land use transformation. The objective of this thesis was the quantification of the spatiotemporal changes of aquatic macrophytes in Finland during the second half of the 1900s. Mapped aquatic macrophyte cover from historic (1947–1963) and present day (1996–2000) aerial photographs, additional macrophyte data and several environmental variables were used to identify the main determinants of aquatic macrophyte distribution, abundance and change. Furthermore, factors influencing the littoral paludification process were identified. The study was conducted in 24 boreal lakes (41–1116 km2) with multisource vegetation data. Selected environmental variables of water level regulation, eutrophication and geomorphology were collected and analyzed. More than 402 km of littoral shoreline in historic and present day aerial photographs was analyzed with stereoscopic visual interpretation. A total of 474 habitat level study sites were used to examine the determining environmental factors of occurrence, abundance and change of emergent vegetation. Finally, 289 vegetation transects were performed in order to study the occurrence, types and main determinants of littoral paludification. Water level regulation was found to be the primary factor behind aquatic macrophyte vegetation development at the whole lake level. The major vegetation changes were determined by the mean water level rise or reduction, decreased fluctuation range and reduced spring flood. The vegetation response was less pronounced in a lake with water level regulation similar to natural fluctuation. Eutrophication influenced aquatic macrophytes at the site level. Land use variables of tributary and agriculture, indicating nutrient increment, corresponded positively with vegetation occurrence and abundance. Geomorphology explained vegetation development at the habitat level. Clay and related deposits and the shore slope specified the vegetation occurrence and affected the abundance of vegetation. Water level regulation, eutrophication, clay and shallowness were found to influence paludification. Helophyte species, common reed (Phragmites australis) and water horsetail (Equisetum fluviatile), dominated the emergent vegetation in the studied lakes
Tiivistelmä Viimeisen puolen vuosisadan aikana suomalaisiin suurjärviin on kohdistunut lukuisia muutoksia, jotka ovat vaikuttaneet järvien ekologiseen tilaan. Muutoksia ovat aiheuttaneet pääasiallisesti vesistöjen säännöstely, rehevöityminen sekä maankäytön muuttuminen. Tämän väitöskirjan tarkoituksena on analysoida noin viimeisten 50 vuoden aikana suomalaisissa suurjärvissä tapahtunutta ranta- ja vesikasvillisuuden pitkäaikaismuutosta. Historiallisilla (1947–1963) ja nykyisillä (1996–2000) ilmakuvilla, muilla kasvillisuusaineistoilla sekä useilla ympäristömuuttujilla tunnistettiin keskeisiä tekijöitä, jotka vaikuttivat kasvillisuuden esiintymiseen, runsauteen ja muutokseen. Tämän lisäksi tutkittiin rantojen pysyvän umpeenkasvun kehitysprosessia. Tutkimusta varten kasvillisuudesta kerättiin monilähdeaineistoa kaikilta Suomen päävaluma-alueilta yhteensä 24 eri järveltä, joiden koko vaihteli 41–1116 km2:n välillä. Tämän lisäksi useita vesistöjen säännöstelyn, rehevöitymisen ja geomorfologian ympäristömuuttujia kerättiin ja analysoitiin. Stereoskooppisella visuaalisella ilmakuvatulkinnalla tutkittiin yli 402 kilometriä rantaviivaa historiallisista ja nykyisistä ilmakuvista. Ilmaversoisen ranta- ja vesikasvillisuuden esiintymistä, runsautta ja historiallista muutosta analysoitiin 474 habitaattitason tutkimuspisteellä. Rantojen pysyvän umpeenkasvun esiintymistä, umpeenkasvun eri tyyppejä ja sitä määrittäviä tekijöitä tutkittiin 289 kasvilinjalla. Tutkimuksen tuloksena havaittiin, että järvitasolla vesistöjen säännöstely oli tärkein kasvillisuuden historialliseen kehitykseen vaikuttava tekijä. Huomattavimmat kasvillisuusmuutokset määräytyivät keskiveden noston, pienentyneen säännöstelyvälin, vähentyneen kevättulvan ja lasketun keskiveden tason seurauksena. Kasvillisuusmuutokset eivät olleet niin selviä, jos säännöstely muistutti luonnontilaista säännöstelyä. Rehevöityminen vaikutti ranta- ja vesikasvillisuuteen paikallisesti. Ravinteisuutta ilmentävät maankäytön muuttujat, ojat sekä maanviljelys, lisäsivät kasvillisuuden esiintymistä ja runsautta. Geomorfologiset tekijät selittivät kasvillisuuden kehitystä habitaattitasolla. Savinen maaperä sekä rannan mataluus lisäsivät vesi- ja rantakasvillisuuden esiintymistä sekä kasvillisuuden runsautta. Vesistöjen säännöstely, rehevöityminen, savinen maaperä sekä rannan mataluus lisäsivät rantojen pysyvää umpeenkasvua. Ilmaversoiset kasvilajit, järviruoko (Phragmites australis) ja järvikorte (Equisetum fluviatile), hallitsivat kasvillisuutta tutkituissa järvissä

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8

Yazgan, Tavsanoglu Ulku Nihan. "Zooplankton Adaptation Strategies Against Fish Predation In Turkish Shallow Lakes". Phd thesis, METU, 2013. http://etd.lib.metu.edu.tr/upload/12615354/index.pdf.

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In this study, the factors influencing zooplankton community structure in Turkish shallow lakes were elucidated with four main approaches: (i) space-for-time substitution for shallow lakes using snap-shot sampling in 31 lakes along a latitudinal gradient
(ii) in-situ mesocosm experiments in eleven lakes along a latitudinal gradient using three sets of artificial plants systems
(iii)&lsquo
Habitat Choice&rsquo
laboratory experiments mimicking a &lsquo
shallow littoral&rsquo
zone with plants and a &lsquo
deeper pelagic&rsquo
zone with sediments testing the response of Daphnia magna to predation cues
and (iv) long-term monitoring data (1997-2011) from two interconnected lakes. Snap-shot and long-term monitoring showed that eutrophication has a strong influence on the zooplankton community via increased fish predation, nutrient loading and salinization. Here too the zooplankton community shifted towards a smaller sized profile, especially in lakes located at lower latitudes. Moreover, The laboratory and in-situ mesocosm experiments revealed that under predation risk Daphnia preferred to hide near sediment instead of using submerged plants as a refuge. Accordingly, in-situ mesocosm experiments revealed a predation pressure induced size structure shift towards small-medium sized zooplankton and calanoid copepods. The long-term monitored lakes experienced (i) drought-induced water level drop, leading to increased salinity and eutrophication, and consequent anoxic conditions and fish kill
as well as (ii) biomanipulation in the downstream. Both conditions resulted in major reduction in the top-down control of fish and ultimate predomination by large sized Daphnia spp. Nevertheless, the excessive exploitation of lakes and ongoing warming entail Turkish shallow lakes to become more eutrophic, making this study indicative for the Mediterranean region.

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9

Kuang, Xingxing y 匡星星. "Air and water flows induced by water level change in aquifers". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2013. http://hdl.handle.net/10722/196080.

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The study of air and water flows induced by water level changes is important for a better understanding of water release in response to pumping in unconfined aquifers and give new insights into pumping test data analysis. To improve the unsaturated flow and air-water two-phase flow numerical modeling of unconfined aquifer pumping tests, an improved unsaturated hydraulic conductivity model and a new relative air permeability model were proposed. A synthesis of the literature on subsurface airflow induced by natural forcings was presented to provide a better understanding of the generated airflow and its importance in environmental and engineering applications. A literature review was carried out to study the naturally occurring subsurface airflow. Analytical studies were carried out to derive the improved unsaturated hydraulic conductivity model and the new relative air permeability model. Experimental studies were conducted to investigate the air and water flows induced by drainage and pumping and numerical simulations were carried out using TOUGH2 and TOUGH2-MP to interpret the experimental data. Numerical models for unconfined aquifer pumping test analysis were built with TOUGH2-MP to investigate the effect of heterogeneity on pumping test results. The study of relative permeability models found that the relative permeabilities predicted by the proposed models are in better agreement with experimental data than existing models. Experimental and numerical investigations on air and water flows induced by drainage and pumping found that significant negative air pressure can be generated in a two-layered system with a low-permeability upper layer. The negative air pressure increases very fast after the start of pumping or drainage, reaches a maximum, and then gradually recovers to atmospheric pressure. The generated negative air pressure can significantly reduce the drainage of water from the column and increase the drawdown. Numerical studies of the effects of local heterogeneity on unconfined aquifer pumping test results found that the drawdown in an unconfined aquifer with a low-permeability zone is significantly greater than that of the homogeneous aquifers but the impact of the low-permeability zone diminishes in the long-term production period. This study presents state of knowledge on naturally occurring subsurface airflow and its implications, proposes improved and new relative permeability models for unsaturated flow and multiphase flow modeling, and offers new insights into the effect of air on water release and unconfined aquifer pumping test data analysis. The present study not only has theoretical significance but also has engineering implications.
published_or_final_version
Earth Sciences
Doctoral
Doctor of Philosophy

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10

Sara, Barghi. "Water Management Modelling in the Simulation of Water Systems in Coastal Communities". Thèse, Université d'Ottawa / University of Ottawa, 2013. http://hdl.handle.net/10393/24364.

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It is no longer a question of scientific debate that research declares our climate is changing. One of the most important and visible impacts of this phenomenon is sea level rise which has impacts on coastal cities and island communities. Sea level rise also magnifies storm surges which can have severely damaging impacts on different human made infrastructure facilities near the shorelines in coastal zones. In this research we are concerned about the proximity of water systems as one of the most vulnerable infrastructures in the coastal zones because of the impact of stormwater combining with sewage water. In Canada, the government has plans to address these issues, but to date, there needs to be further attention to stormwater management in coastal zones across the country. This research discusses the impacts of severe environmental events, e.g., hurricanes and storm surge, on the water systems of selected coastal communities in Canada. The purpose of this research is to model coastal zone water systems using the open source StormWater Management Modelling (SWMM) software in order to manage stormwater and system response to storms and storm surge on water treatment plants in these areas. Arichat on Isle Madame, Cape Breton, one of the most sensitive coastal zones in Canada, is the focal point case study for this research as part of the C-Change International Community-University Research Alliance (ICURA) 2009-2015 project.

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11

Persio, Andrew Franklin. "Assessment of changes in the water-surface profile of the lower canyon of the Little Colorado River, Arizona". Thesis, The University of Arizona, 2004. http://etd.library.arizona.edu/etd/GetFileServlet?file=file:///data1/pdf/etd/azu_etd_hy0124_sip1_w.pdf&type=application/pdf.

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12

Ali, Syed Mahtab. "Climate change and water management impacts on land and water resources". Curtin University of Technology, Faculty of Engineering and Computing, Dept. of Civil Engineering, 2007. http://espace.library.curtin.edu.au:80/R/?func=dbin-jump-full&object_id=18688.

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This study evaluated the impacts of shallow and deep open drains on groundwater levels and drain performance under varying climate scenarios and irrigation application rates. The MIKE SHE model used for this study is an advanced and fully spatially distributed hydrological model. Three drain depths, climates and irrigation application rates were considered. The drains depths included 0, 1 and 2 m deep drains. The annual rainfall and meteorological data were collected from study area from 1976 to 2004 and analysed to identify the typical wet, average and dry years within the record. Similarly three irrigation application rates included 0, 10 and 16 ML/ha-annum. All together twenty seven scenarios (3 drains depths, 3 climates and 3 irrigation application rates) were simulated. The observed soil physical and hydrological data were used to calibrate and validate the model. Mean square error (R[superscript]2) of the simulated and observed water table data varied from 0.7 to 0.87. Once validated the MIKE SHE model was used to evaluate the effectiveness of 1 and 2 metre deep drains. The simulated water table depth, unsaturated zone deficit, exchange between unsaturated and saturated zones, drain outflow and overland flow were used to analyse their performance. The modeling results showed that the waterlogging was extensive and prolonged during winter months under the no drainage and no irrigation scenario. In the wet climate scenario, the duration of water logging was longer than in the average climate scenario during the winter months. In the dry climate scenario no waterlogging occurred during the high rainfall period. The water table reached soil surface during the winter season in the case of wet and average climate. For the dry climate, the water table was about 0.9 metres below soil surface during winter.
One and 2 metre deep drains lowered the water table up to 0.9 and 1.8 metres in winter for the wet climate when there was no irrigation application. One metre deep drains proved effective in controlling water table during wet and average climate without application of irrigation water. One metre deep drains were more effective in controlling waterlogging a in wet, average and dry years when the irrigation application rate was 10 ML/ha-annum. With 16 ML/ha-annum irrigation application, 1 metre deep drains did not perform as efficiently as 2 metre deep drains in controlling the water table and waterlogging. In the dry climate scenario, without irrigation application, 1 metre deep drains were not required as there was not enough flux from rainfall and irrigation to raise the water table and create waterlogging risks. Two metre deep drains lowered the water table to greater depths in the wet, average and dry climate scenarios respectively when no irrigation was applied. They managed water table better in wet and average climate with 10 and 16 ML/ha-annum irrigation application rate. Again in the dry climate, without irrigation application 2 metre deep drains were not required as there was a minimal risk of waterlogging. The recharge to the groundwater table in the no drainage case was far greater than for the 1 and 2 metre deep drainage scenarios. The recharge was higher in case of 1 metre deep drains than 2 metre deep drains in wet and average climate during winter season.
There was no recharge to ground water with 1 and 2 metre deep drains under the dry climate scenarios and summer season without irrigation application as there was not enough water to move from the ground surface to the unsaturated and saturated zones. When 10 ML/ha-annum irrigation rate was applied during wet, average and dry climate respectively, 1 metre deep drains proved enough drainage to manage the recharge into the groundwater table with a dry climate. For the wet and average climate scenarios, given a 10 ML/ha-annum irrigation application rate, 2 metre deep drains managed recharge better than 1 metre deep drains. Two metres deep drains with a 10 ML/ha-annum irrigation application rate led to excessive drainage of water from the saturated zone in the dry climate scenario. Two metres deep drains managed recharge better with a 16 ML/ha-annum irrigation application rate in the wet and average climate scenarios than the 1 metre deep drains. Two metres deep drains again led to excessive drainage of water from the saturated zone in dry climate. In brief, 1 metre deep drains performed efficiently in the wet and average climate scenarios with and without a 10 ML/ha-annum irrigation application rate. One metre deep drains are not required for the dry climate scenario. Two metre deep drains performed efficiently in the wet and average climate scenarios with 16 ML/ha-annum irrigation application rate. Two metre deep drains are not required for the dry climate scenario.

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13

Mic, Dumitrita Suzana. "Producing Collaborations Through Community-Level Processes of Climate Change and Water Management Planning". FIU Digital Commons, 2015. http://digitalcommons.fiu.edu/etd/2170.

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While much attention has been given to the ways local communities may be impacted by climate change, this dissertation focuses ethnographically on the local agencies decision-making processes, a less-studied aspect of this topic. The primary purpose of this dissertation research is to understand how government agencies in southern Florida integrate climate change into their decision-making processes while dealing with political resistance. This research expands our understanding on the cultural politics of a new kind of environmental change, where national and international climate-change politics is brought into local water politics to illuminate how new and not so new visions about life in the contemporary metropolis collide and collude. Using multiple research methods including ethnographic fieldwork, participant observation, semi-structured interviews, and document research, I analyze the activities of the Miami-Dade County Climate Change Advisory Task Force Committee (MDC-CCATF) as well as the water management practices of the regional water management agency, the South Florida Water Management District (SFWMD). My findings include the following: (1) the Task Force activities have spearheaded Miami’s institutional adaptation to climate change; (2) historic legacies have expanded and complicated decision-making processes at the District; (3) a focus on the certainties of climate-change science allows climate change to persist in politically contentious planning contexts. My dissertation concluded that while planning for potential climate-change impacts can be difficult due to multiple institutional constraints that resource agencies like the District have, scientists and policy-makers have crafted an innovative culture that is particularly visible at sites where science and decision making intersect.

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14

Beygi, Heydar. "Impact of irrigation development and climate change on the water level of Lake Urmia, Iran". Thesis, Stockholms universitet, Institutionen för naturgeografi, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-120270.

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Lake Urmia, located in the north-west of Iran, is one of the largest hypersaline lakes in the world. In recent years, there has been a significant decrease in the lake’s area and volume by 88% and 80% respectively. An integrated water balance model of the Lake Urmia Drainage Basin (LUDB) and Lake Urmia was developed to identify these main drivers of the significant changes, and to investigate the possible future evolution of the lake under effects of projected climate change and land use change. We used an energy balance method to estimate the evaporation from the lake and the Turc-Langbein method to estimate the evapotranspiration from the drainage basin of the lake. Agricultural irrigation water was introduced to the model as an extra precipitation over the irrigated fields, after being subtracted from the surplus runoff (precipitation−evapotranspiration). The agricultural land development was assumed to be linear that changed from 300000 ha at 1979 to 500000 at 2010, which is consistent with the best available data on the actual irrigation development in the basin. We estimated the annual evaporation over the Lake Urmia and the evapotranspiration over its drainage basin as 932 mm and 287 mm respectively. Our results showed that decreased precipitation and increased temperature over the basin since 1995 could explain 68% of the observed lake level decrease. Irrigation developments during the last four decades were found to be responsible for 32% of the observed lake level decrease. Thus the future lake level of the Lake Urmia is very likely to continue to decrease unless the current climate condition will be followed by a period of increased precipitation. If the current climate conditions will prevail also in the future, even a 20% decrease in the irrigated land area, which is actually quite ambitious, will not make the lake recover to its ecological level at the end of 2020.

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15

Ripley, Dana Cameron. "Changes in Soil Salinity Levels with the Use of Recycled Water on Cool Season Vegetables". DigitalCommons@CalPoly, 2013. https://digitalcommons.calpoly.edu/theses/1111.

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Agricultural production in Monterey County, California is a multi-billion dollar industry. Near the coast, seawater intrusion has threatened to degrade the groundwater quality due to over-pumping of the aquifer. The Monterey Regional Water Pollution Control Agency (MRWPCA), in partnership with the Monterey County Water Resources Agency, has provided recycled water since 1998 to over 12,000 acres of prime agricultural farmland in the northern Salinas Valley in an effort to reduce groundwater removal. The dominant soil types in the region are clay loam and clay soils, which are both susceptible to sodium (Na) accumulation and water infiltration problems. Recycled water blended with well water is used to irrigate cool season vegetables (i.e., artichokes, broccoli, Brussels sprouts, celery, cauliflower, and lettuce) and strawberries. A long-term study was implemented by MRWPCA to monitor salinity levels in commercial vegetable fields because of grower concerns that salts in the recycled water would have long term effects on soil quality. Accumulation of salts over time would make the soil less productive. Soil salinity levels were monitored at three Control and three Test Sites beginning in the spring of 2000. The Control Sites received well water, and the adjacent Test Sites received an approximate 2:1 blend of recycled and well water, respectively. Control and Test Sites were paired based on location to compare the same soil, crop, drainage systems, and farming practices. The soil was sampled three times per year from all sites: spring (before planting), mid-summer after harvest of the first crop, and late fall after the second crop harvest. Composites of four cores were collected at each site from the zero to 36-inch depth at 12-inch intervals. Each 12-inch interval soil sample was analyzed for pH, electrical conductivity (ECe), extractable cations (Na+, Ca2+, Mg2+, and K+) and extractable anions (Cl-, NO3-, and SO4-). After 10 years of monitoring, the data showed that using recycled water blended with well water at the Test Sites increased the ECe of the soil profile from 2.1 to 2.5 dS/m and increased the sodium adsorption ratio (SAR) from 3.0 to 3.9. The data also showed that using well water at the Control Sites increased the ECe of the soil profile from 1.4 to 2.6 dS/m and the change in SAR was negligible. The Test and Control Sites were significantly different for ECe and SAR, which was expected considering a higher salt content in the recycled water compared to the well water. The significant differences for ECe and SAR were associated with the significant differences in soil Na+ levels between the Test and Control Sites. The SAR and ECe of soil samples from all sites were in a range acceptable for vegetable production. The use of recycled water for irrigation of cool season vegetables and strawberries in the study area has not shown an indication of degraded soil productivity. Based on vegetable production and the slow increase of salts in the soil, recycled water can be used for long-term irrigation with proper management.

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16

Wegerich, Kai. "Institutional change in water management at the local and provincial levels in Uzbekistan". Thesis, SOAS, University of London, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.404826.

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The dis-integration of the Soviet Union has led to changes in agricultural and natural resource management in the Central Asian successor states. These changes affected not only the international and national levels of governance but also the provincial and local level governance of the different republics. The focus of the research is on institutional change at the local level in the agricultural sector in Uzbekistan. The study area is located in the downstream regions of the Amu Darya basin, in the Khorezm province and the Karakalpakstan republic. Since the year 2000 a small number of state and collective farms have been privatised and farm organisations and water users associations have been established. The thesis deploys political theory, social theory and new institutional economics to analyse and examine institutions and institutional change and to analyse local level transformations. Particular attention is given to key stakeholders in the agricultural sector and in water management organisations at the local and provincial levels and to how they implemented the change. The main findings of the thesis first, confirm that institutions reduce negotiation and discourse costs by providing a structure for contention and accommodation. However, the findings indicate that institutions also have negative effects, because they reflect and reinforce old power relations and therefore can be exploited to serve the interests of privileged former stakeholders. The second main finding is that institutions and their ability to effect change is determined by the power of influential stakeholders, who enable or reject change. The findings of the thesis are important for those developing strategies for the creation of bottom-up movements, and also for the social engineering and reengineering of larger institutions and organisations. The findings will be especially significant for those involved in land and water reform processes and in the privatisation of governmental industries.

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17

Furze, Mark Fernley Alexander. "Late Pleistocene sea-level change in the Celtic Sea : radiocarbon dated macrofauna as palaeo-water-depth indicators". Thesis, Bangor University, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.367395.

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18

Michelli, Maximiliano [Verfasser]. "Sea-level changes, coastal evolution and paleoceanography of coastal waters in SE-Vietnam since the mid-Holocene / Maximiliano Michelli". Kiel : Universitätsbibliothek Kiel, 2009. http://d-nb.info/1019810319/34.

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19

Healy, Strömgren William. "Automatic Adjustment of the Floatation Level for a Tight-moored Buoy". Thesis, Uppsala University, Department of Earth Sciences, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-88883.

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Denna rapport ger förslag på olika metoder att automatiskt justera flytläget på en statiskt förankrad boj, en överblick över de processer som styr ändringen av vattennivån och en statisktisk analys på vattennivåförändringarna vid Stockholm, Kungsholmsfort och Kungsvik.

Beroende på vattenivåns variation finns olika metoder för justering. Områden med små variationer av vattennivå lämpar det sig bäst utan någon som helst justering av flytläget. Områden med inte för stora tidvattensförändringar bör justeras med ett system bestående av vinsch, växellåda med en utväxling på 10 000:1, en 12 V DC motor, ett skötselfritt 12 V batteri, en luftlindad linjärgenerator och en trådtöjningsgivare. Områden med stora variationer i tidvatten behöver en avlastning för motorn i form av en fjäder och dämpare. De monteras horizontellt inuti bojen för att skyddas från den yttre miljön.

Den statistiska analysen påvisade de största vattennivåändringarna vid både Kungsviks och Kungsholmsforts mätstationer, båda uppvisade ett intervall på 1,6 m mellan minimum och maximum. Kungsvik var den station med de största dagliga variationerna, detta på grund av tidvattnets påverkan i området.

This thesis gives examples of different methods of automated adjustment of floatation level for a static moored buoy, an overview of the theories behind water level change and a statistical analysis of the water level changes for Stockholm, Kungsholmsfort and Kungsvik.

Depending on the range and frequency of the water level change different methods of adjustment are recommended. For areas with small changes in sea level the best choice would be no adjustment of the floatation level. Areas that are influenced by moderate tidal ranges should incorporate a system of regulation consisting of a winch, gearbox with a gear ratio of around 10,000:1, 12 V DC motor, 12 V maintenance free battery, air coiled linear generator and a strain gauge. For areas with large tidal ranges the previous system should be complimented with a horizontally mounted spring, inside the buoy, to lessen the loads on the motor.

The statistical analysis found the largest extremes in water level of the three sites to be at Kungsvik and Kungsholmsfort, both exhibiting a range of almost 1.6 m. Kungsvik was the station with the largest daily variations, this is because this is the only station influenced by tidal variations.

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20

Khan, Zishann. "Origin and Architecture of Deep-water Levee Deposits: Insight from the Ancient Rock Record and Experiments". Thèse, Université d'Ottawa / University of Ottawa, 2011. http://hdl.handle.net/10393/20494.

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Although levee deposits make up a significant part of modern and ancient deep-marine slope systems, details of their internal lithological composition and stratal architecture remain poorly documented. At the Castle Creek study area, strata of the Neoproterozoic Isaac Formation (Windermere Supergroup) crop out superbly in a kilometre-scale section through a sinuous deep-water channel-levee system (ICC3). Levee deposits near the outer bend of the channel consist of sandstone-rich (sandstone-to-mudstone ratio of 68:42), medium- to thick-bedded turbidites interstratified with thinly-bedded turbidites. Structureless sandstone (Ta), planar laminated sandstone (Tb), non-climbing ripple cross-stratified sandstone (Tc) and massive and laminated siltstone (Td) are common. Thick beds generally thicken and then thin and fine laterally over about 300 m. Thin-bedded strata, in contrast, thin and fine negligibly over similar distances. In the distal part of the outer-bend levee (up to 700 m laterally away from the channel) strata consist predominantly of thin-bedded Tcd turbidites with a much lower sandstone-to-mudstone ratio (35:65). On the opposite side of the channel, inner-bend levee deposits are mudstone-rich, locally as low as 15:85, and consist mostly of thin-bedded, Tcd turbidites, although thicker-bedded, Ta-d turbidites are more common in the lower part of the section. Lateral thinning and fining of beds is more rapid than their outer-bend counterpart. Levee deposits of ICC3 comprise three stacked decametre-scale upward-thinning and -fining successions. Each is interpreted to record a depositional history consisting of lateral channel migration, levee deposition, channel filling, and distal levee deposition. During the early stage of increasing levee relief it is proposed that the termini of individual beds progressively backstep towards the channel margin resulting in an overall lateral thinning of the stratal profile. This interpretation notably contrasts the common assumption that levee morphology is the result of the vertical stacking of beds that dip. In addition to field studies, laboratory experiments were conducted to determine the depositional threshold of non-climbing ripple cross-stratification, which is common in levee strata of ICC3. It was determined that non-climbing ripples form when bed aggradation rates are less than 0.015 cm/sec, and most probably in flows made up of poorly sorted sediment.

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21

Andersson, Sofia y Elin Lundkvist. "Torkans effekt på dricksvattenförsörjningen i Mälarregionen : En studie om kommuners arbete med vattenfrågor utifrån erfarenheter från 2017". Thesis, Uppsala universitet, Luft-, vatten och landskapslära, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-352459.

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Uppsatsens syfte är att undersöka om kommuner i Mälarregionen drabbades av låga yt- och grundvattennivåer under sommaren 2017, hur situationen hanterades, deras dagliga arbete med vattenfrågor och om handlingsplaner fanns för låga nivåer före 2017. Vi vill även se hur kommunerna ställer sig till klimatförändringar samt sammanställa vilka roller och ansvar som olika myndigheter har när det kommer till vattenförsörjning. Arbetets undersökningsområde begränsades till 39 kommuner i fyra län: Södermanlands, Upplands, Västmanlands och Örebro län. För att besvara syftet skickades en enkät ut till kommunerna och intervjuer genomfördes med två av kommunerna. En litteraturstudie genomfördes för att kunna besvara ansvarsfördelningen mellan olika myndigheter. Enkäten besvarades av 26 kommuner. Det viktigaste resultat var att kommunerna, trots vattennivåer under det normala, inte upplevde vattenbrist i den omfattningen som vi trott. Fem kommuner angav att de drabbades av vattenbrist. Den huvudsakliga åtgärden som infördes var bevattningsförbud. Från enkäten framkom att det i stor utsträckning saknats handlingsplaner för att hantera en situation med vattenbrist innan 2017. Majoriteten av kommunerna tror att deras vattenförsörjning kan påverkas av klimatförändringar, men bara 14 angav att de har en handlingsplan för det. Resultatet som framkom från intervjuerna gällde främst processen för införandet av skyddsområden. Även i litteraturstudien framkom det att arbetet med vattenskyddsområden inte går i den takt som är nödvändig för att nå målen förhållbar och långsiktig dricksvattenförsörjning.
The aim of this paper is to examine how municipalities in the Mälar region of Sweden were affected by the low surface and groundwater levels in the summer of 2017, how municipalities handled the situation, how they work with water related questions in their daily work and whether they had an action plan for dealing with shortage of water prior to 2017. Lastly, we also aim to compile the roles and responsibilities for different authorities when it comes to water supply. The area of study was limited to 39 municipalities in four counties: Södermanlands, Upplands, Västmanlands and Örebro county. To answer the aim, a survey was sent out to all municipalities and interviews were done with two of the municipalities. A literature study was done in order to answer the division of responsibilities between different authorities. The survey was answered by 26 municipalities. The main result we got from the survey was that even though the water levels were below normal, the municipalities didn’t experience water shortages in the extent we had expected. Five municipalities indicated that they had been affected by the water shortages. The main measure that were done was the irrigation ban. From the survey it was found that most of the municipalities were lacking action plans to deal with a water shortage situation before2017. The majority of the municipalities believe that their water supply can be affected by climate change, but only 14 indicated that they have an action plan for it. The results obtained from our interviews primarily marks the division of responsibilities for water conservation areas. As conducted from the literature study, the processes to constitute water conservation areas does not seem to be smooth and quick enough to meet the goals of sustainable and long-term water supply.

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22

Anderson, Heather Christine. "Amphibious Architecture : Living with a Rising Bay". DigitalCommons@CalPoly, 2014. https://digitalcommons.calpoly.edu/theses/1258.

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Over the past century, sea level has risen nearly eight inches along the California coast and climate scientists suggest substantial increases in sea level as a significant impact of climate change over the coming century. This project explores the concept of creating a sustainable living environment for seaside residents in Redwood City as an alternative to permanent construction on land in the event of a substantial rise in sea level. This project will generate a flood-resilient design solution that is capable of rising and falling with the water. In order to ensure the well-being of the inhabitants, I will analyze a number of case studies, notably the Netherland’s water dwellings, New Orleans’s amphibious residences and Sausalito’s floating communities, for the purpose of identifying key themes that will facilitate the construction of a single-family amphibious residence in Redwood City. This project is a response to environmental design challenges raised by ongoing atmospheric events such as the gradual rise in sea level and disastrous events such as Hurricane Katrina in 2005 where extreme flooding due to failed coastal defenses exhibited catastrophic effects on coastal residences, its inhabitants, and the surrounding ecosystem.

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23

Komorová, Magdaléna. "Historický vývoj zanášení horní nádrže VD Nové Mlýny". Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2020. http://www.nusl.cz/ntk/nusl-409715.

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Master thesis is about historical deposition of sediments in the upper reservoir of Nové Mlýny from first fill up with water until present time. Beginning of the thesis concentrates on introduction of types of sediments and their behavior in rivers and reservoirs, sediment deposition in reservoirs and measures against sedimentation in reservoir. Part of the thesis consist of the creation of numerical one-dimensional model with transport of sediments on sections of rivers Dyje, Jevišovka and in the upper reservoir. Output data evaluation consist of analysis of sediment’s volume, development of bed in time and variation of bed evaluation in reservoir. Master thesis evaluates the development of water surface with different stages of sedimentation.

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24

Bauer, Göran. "Modeling additional waterflows in sewage systems in Sweden – An outlook on the impact of climate change". Thesis, KTH, Mark- och vattenteknik (flyttat 20130630), 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-171826.

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This study assesses the phenomenon of additional water intruding into sewage sys-tems in different areas of Sweden. Additional water means in this case the non-foul water that can originate from storm water runoff, which is either supposed to be con-veyed into the pipe system or intrudes it by wrongly connected drains. It can also re-sult from in-seepage of groundwater due to imperfections of the pipe system itself. It is intended to analyze how different features of the areas have an impact on the extent of this phenomenon. Further, an estimation of the conditions in future scenarios will be obtained. This includes an indication about the potential risk of a sewage system overflow, the expected volume of inflow at treatment plants and thus about the sys-tem´s suitability for the future. Numerical, hydrological compartment models for 19 cities in Sweden were set-up. The used parameters were obtained from previous studies by the Swedish Environ-mental Protection Agency. In these models present and future climate data were ap-plied. For future scenarios three different climate change projections were used which contain bias corrected climate data timeseries for each study area. The climate change scenarios were supposed to represent an "optimistic", "average" and "pessimistic" outlook. By assessing the outputs of the climate models, it was concluded that signifi-cant differences can occur, depending on exact geographical location and chosen cli-mate models. A sensitivity analysis was conducted of how geology, climate and status of the pipe system have an impact on the extent of additional water flows. It revealed that the status of the sewage system has by far the biggest impact. Finally a discharge analysis showed a potential outlook of future development of additional water flows for the chosen study sites, yielding highest increase for the sewage systems of Kiruna, Karlskoga and Sundsvall.

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25

Torres, Maria Madalena Bernardes de Miranda Freire. "O estuário do Tejo em 2100. Projectar a frente ribeirinha em cenários de alterações climáticas : Alhandra, Welcome Water". Master's thesis, Faculdade de Arquitetura de Lisboa, 2012. http://hdl.handle.net/10400.5/5777.

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26

Chu, Thi Thu Ha. "State of the environment and natural resources in Vietnam". Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-176875.

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Vietnam is considered as one of the countries having rich resources from forest and sea, with a high average annual rainfall. However, in view of IWRA, water volume per capita annually in Vietnam is lower than the standard for nations having water resources at average level. Vietnam was recognized by the World Wildlife Fund (WWF) as having three out of more than 200 biological zones of the world. Flora and fauna in Vietnam are very rich and abundant, but due to indiscriminate exploitation, along with weak management, biodiversity levels are significantly reduced. This is also one of the causes of environmental pollution and degradation in Vietnam, besides the impacts from production activities, population migration from rural areas to urban areas, rapid urbanization, climate change and sea level rise, etc
Tảo đóng vai trò quan trọng trong mạng lưới thức ăn và chu trình sinh địa hóa của thủy vực và chúng chịu sự chi phối của nhiều yếu tố môi trường như ánh sáng, pH, nhiệt độ và dinh dưỡng. Nghiên cứu này trình bày đa dạng thành phần loài và biến động sinh khối thực vật phù du tại hồchứa Hòa Bình từ tháng 3 đến tháng 12 năm 2011. Các mẫu thực vật nổi được thu thập hàng tháng tại 4 điểm. Kết quả đã xác định được 6 lớp tảo chính bao gồm: Vi khuẩn lam, tảo lục, tảo silic, tảo mắt, tảo giáp và tảo lông roi hai rãnh. Nhóm tảo silic và Vi khuẩn lam chiếm ưu thế với độ phong phú tương đối là 61% và 32% tương ứng trong quần xã thực vật nổi. Vi khuẩn lam dạng tập đoàn và dạng sợi (Microcystis aeruginosa, M. wesenberg, Oscillatoria sp. tương ứng) chiếm ưu thế trong quần xã thực vật nổi vào các thời điểm đầu hè và mùa thu (tháng 4 và tháng 9). Tổng mật độ tế bào thực vật nổi dao động từ 84210 đến 100 x106 cell/L. Mật độ thực vật nổi biển động theo mùa với sinh khối tê bào cao vào đầu hè và mùa đông (tháng 4 và tháng 12) và sinh khối tếbào thấp vào các mùa hè và thu (tháng 6 đến tháng 10)

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Chu, Thi Thu Ha. "State of the environment and natural resources in Vietnam". Technische Universität Dresden, 2014. https://tud.qucosa.de/id/qucosa%3A28879.

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Vietnam is considered as one of the countries having rich resources from forest and sea, with a high average annual rainfall. However, in view of IWRA, water volume per capita annually in Vietnam is lower than the standard for nations having water resources at average level. Vietnam was recognized by the World Wildlife Fund (WWF) as having three out of more than 200 biological zones of the world. Flora and fauna in Vietnam are very rich and abundant, but due to indiscriminate exploitation, along with weak management, biodiversity levels are significantly reduced. This is also one of the causes of environmental pollution and degradation in Vietnam, besides the impacts from production activities, population migration from rural areas to urban areas, rapid urbanization, climate change and sea level rise, etc.
Tảo đóng vai trò quan trọng trong mạng lưới thức ăn và chu trình sinh địa hóa của thủy vực và chúng chịu sự chi phối của nhiều yếu tố môi trường như ánh sáng, pH, nhiệt độ và dinh dưỡng. Nghiên cứu này trình bày đa dạng thành phần loài và biến động sinh khối thực vật phù du tại hồchứa Hòa Bình từ tháng 3 đến tháng 12 năm 2011. Các mẫu thực vật nổi được thu thập hàng tháng tại 4 điểm. Kết quả đã xác định được 6 lớp tảo chính bao gồm: Vi khuẩn lam, tảo lục, tảo silic, tảo mắt, tảo giáp và tảo lông roi hai rãnh. Nhóm tảo silic và Vi khuẩn lam chiếm ưu thế với độ phong phú tương đối là 61% và 32% tương ứng trong quần xã thực vật nổi. Vi khuẩn lam dạng tập đoàn và dạng sợi (Microcystis aeruginosa, M. wesenberg, Oscillatoria sp. tương ứng) chiếm ưu thế trong quần xã thực vật nổi vào các thời điểm đầu hè và mùa thu (tháng 4 và tháng 9). Tổng mật độ tế bào thực vật nổi dao động từ 84210 đến 100 x106 cell/L. Mật độ thực vật nổi biển động theo mùa với sinh khối tê bào cao vào đầu hè và mùa đông (tháng 4 và tháng 12) và sinh khối tếbào thấp vào các mùa hè và thu (tháng 6 đến tháng 10).

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28

Khalil, Kamal. "Water surface profile modelling for Pinjarra flood diversion channel and economic evaluation". Curtin University of Technology, Department of Civil Engineering, 2007. http://espace.library.curtin.edu.au:80/R/?func=dbin-jump-full&object_id=17589.

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Shire of Murray has concerns regarding the negative impact that a 100 year flood could have on existing structures built before 1997. The increase cost in construction due to landfill has an adverse effect on development in Pinjarra. Feasibility of constructing a diversion channel at upstream of Murray River to attenuate the flood level from 1 in 100 year ARI to 1 in 50 year ARI, was investigated by Kiong (2003). The Murray River Water Surface Profile along three kilometres south of Greenlands Road was modelled. Flood damages on each flood occurrence were assessed and Average Annual Damage (AAD) was calculated. The AAD is used to estimate the monetary benefit against the construction cost of the diversion channel. Groundwater along Greenlands and Fauntleroy Drains was also modelled to determine the viable depth of the designed channel, as well as the analysis of backwater. The proposed channel is designed at different scenarios (invert level at breakout point, culvert or causeway design, and diversion channel variations). The benefit cost ratio of the proposed diversion channel is calculated. Other mitigation options are suggested including detention basins for structural measure, or building a new flood-proof township for non-structural measure.

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29

Sepúlveda, Toepfer Carlos. "Instrumentation, model identification and control of an experimental irrigation canal". Doctoral thesis, Universitat Politècnica de Catalunya, 2008. http://hdl.handle.net/10803/5951.

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This thesis aims to develop control algorithms for irrigation canals in an experimental framework.
These water transport systems are difficult to manage and present low efficiencies in practice.
As a result, an important percentage of water is lost, maintenance costs increase and water users follow a rigid irrigation schedule.
All these problems can be reduced by automating the operation of irrigation canals.
In order to fulfil the objectives, a laboratory canal, called Canal PAC-UPC, was equipped and instrumented in parallel with the development of this thesis. In general, the methods and solutions proposed herein were extensively tested in this canal.
In a broader context, three main contributions in different irrigation canal control areas are presented.
Focusing on gate-discharge measurements, many submerged-discharge calculation methods are tested and compared using Canal PAC-UPC measurement data. It has been found that most of them present errors around ±10%, but there are notable exceptions. Specifically, using classical formulas with a constant 0.611 contraction value give very good results (error<±6%), but when data is available, a very simple calibration formula recently proposed in the literature significantly outperform the rest (error<±3%). As a consequence, the latter is encouragingly proposed as the basis of any gate discharge controller.
With respect to irrigation canal modeling, a detailed procedure to obtain data-driven linear irrigation canal models is successfully developed. These models do not use physical parameters of the system, but are constructed from measurement data. In this case, these models are thought to be used in irrigation canal control issues like controller tuning, internal controller model in predictive controllers or simply as fast and simple simulation platforms. Much effort is employed in obtaining an adequate model structure from the linearized Saint-Venant equations, yielding to a mathematical procedure that verifies the existence of an integrator pole in any type of canal working under any hydraulic condition. Time-domain and frequency-domain results demonstrate the accuracy of the resulting models approximating a canal working around a particular operation condition both in simulation and experiment.
Regarding to irrigation canal control, two research lines are exploited. First, a new water level control scheme is proposed as an alternative between decentralized and centralized control. It is called Semi-decentralized scheme and aims to resemble the centralized control performance while maintaining an almost decentralized structure. Second, different water level control schemes based on PI control and Predictive control are studied and compared. The simulation and laboratory results show that the response and performance of this new strategy against offtake discharge changes, are almost identical to the ones of the centralized control, outperforming the other tested schemes based on PI control and on Predictive control. In addition, it is verified that schemes based on Predictive control with good controller models can counteract offtake discharge variations with less level deviations and in almost half the time than PI-based schemes.
In addition to these three main contributions, many other smaller developments, minor results and practical recommendations for irrigation canal automation are presented throughout this thesis.

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30

Gardelle, Julie. "Evolution récente des glaciers du Pamir-Karakoram-Himalaya : apport de l'imagerie satellite". Phd thesis, Université de Grenoble, 2012. http://tel.archives-ouvertes.fr/tel-00864042.

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La région du Pamir - Karakoram - Himalaya (PKH) constitue la plus grande réserve de glace terrestre après les régions polaires. Cependant, l'évolution récente de ces glaciers, indicateurs privilégiés du changement climatique en haute altitude, reste encore mal connue, du fait notamment de difficultés d'accès et de conditions climatiques qui rendent délicate l'acquisition de mesures in situ. L'objectif de cette thèse est de contribuer à l'amélioration des connaissances sur l'évolution globale des glaces du PKH au cours de la dernière décennie, en s'appuyant sur des images satellite et des modèles numériques de terrain (MNTs). Une premièreméthodologie a été développée pour assurer le suivi automatique de la distribution spatiale et de l'évolution temporelle des lacs glaciaires à partir d'images Landsat entre 1990 et 2009 sur sept zones d'études réparties le long du PKH. Ainsi, une certaine disparité des types, tailles et évolutions des lacs entre la partie orientale et occidentale du PKH a été mise en évidence. Sur la période de temps considérée, la superficie des lacs a légèrement diminué à l'ouest (Karakoram et Hindu Kush), a été en très nette augmentation à l'est (Népal et Bouthan) et relativement stable sur la partie centrale (Inde du nord-ouest). Le bilan de masse des glaciers a ensuite été calculé, à partir des variations d'épaisseurs mesurées en comparant deuxMNTs, acquis à deux dates différentes, et issus de lamission SRTM et du satellite SPOT5. Cette méthode implique un certain nombre de corrections et d'ajustements au préalable, afin de garantir des mesures les moins biaisées possible. Ainsi, la différence de résolution spatiale initiale des MNTs peut être à l'origine d'un biais fonction de l'altitude, de même que la pénétration des ondes radar de la mission SRTM dans la neige et la glace est à prendre en compte le cas échéant, pour ne pas sous-estimer les altitudes sur les glaciers. Là encore, on observe des disparités entre les différents bilans de masse régionaux sur la période 1999-2011, avec des pertes de masse modérées sur l'Himalaya central et oriental(-0.30±0.08 m a-1 w.e.), plus accentuées sur l'Himalaya occidental (-0.43±0.09 m a-1 w.e.) et des gains de masse plus à l'ouest, pour les glaciers des massifs du Pamir (+0.14±0.11 m a-1 w.e.) et du Karakoram (+0.10±0.20 m a-1 w.e.). Ces résultats confirment donc l'anomalie des glaciers du Karakoram et suggèrent des comportements similaires au Pamir. Le bilan de masse global des glaciers du PKH est estimé à -0.13±0.06 m a-1 w.e.

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31

Englund, Sofia. "Optimizing the design of two-stage ditches to improve nutrient and sediment retention". Thesis, Uppsala universitet, Institutionen för geovetenskaper, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-415420.

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Negative effects on water quality are created by eutrophication of the world’s water resources. Mitigation measures have been implemented, but poor improvements in water quality have been observed. Two-stage ditches have the possibility to increase nutrient and sediment retention to reduce eutrophication in receiving water bodies. A two-stage ditch has floodplain terraces on each side of the ordinary main channel. The terraces are available for flooding during high water flows and enables decreases in flow velocities. However, more knowledge is needed about the two-stage ditch and its effect in Swedish landscapes. The aim of the project was to study the two-stage ditch design with focus on water retention. Optimization of the two-stage ditch design was made by modeling and simulating design parameters and vegetation in the software Hydrologic Engineering Center’s River Analysis System (HEC-RAS). An existing two-stage ditch in Sweden was used as base and comparison to the theoretical model. In addition, a climate change scenario was studied to evaluate the impact of increased storm events in a two-stage ditch. Results showed that increased retention time of water, nutrients, and sediments theoretically can be given by designing two-stage ditches with maximum terrace width and minimum terrace height, and with terraces angled away from the main channel. Vegetation should also be kept on both terraces and in the main channel of the two-stage ditch to increase retention time. The study also showed that the two-stage ditch design has the possibility to decrease peak water levels during storm events, which can be expected to increase in the future. The impact on transport of nutrients and sediments from more future extreme hydrological events needs further studies.
Negativa effekter i vattenkvalitet skapas av övergödning i världens vattenresurser. Åtgärder för att begränsa övergödningen har genomförts, men svaga förbättringar i vattenkvalitet har noterats. Tvåstegsdiken har möjligheten att öka retentionen av näringsämnen och sediment för att minska övergödning. Ett tvåstegsdike har terrasser på vardera sida om den vanliga mittfåran. Terrasserna är tillgängliga för översvämning vid höga vattenflöden, vilket möjliggör minskning av flödeshastigheter. Dock krävs mer kunskap för tvåstegsdiken och dess effekt i svenska landskap. Syftet med projektet var att studera designen av tvåstegsdiken med fokus på retention av vattenflöde. Optimering av tvåstegsdikens design genomfördes via modellering och simulering av designparametrar och vegetation i programvaran Hydrologic Engineering Center’s River Analysis System (HEC-RAS). Ett befintligt tvåstegsdike i Sverige användes som bas och jämförelse mot den teoretiska modellen. Ett scenario för klimatförändring studerades även för att utvärdera effekten i ett tvåstegsdike då fler stormevent sker. Resultaten visade att ökad retentionstid for vatten, näringsämnen, och sediment teoretiskt kan ges genom att designa tvåstegsdiken med maximal terrassbredd och minimal terrasshöjd, samt med terrasser vinklade bort från mittfåran. Vegetation bör även behållas på terrasser och i mittfåran av tvåstegsdiket för att öka retentionstiden. Studien visade även att tvåstegs- dikets design har möjligheten att minska toppflöden vid stormevent, vilka kan förväntas öka i framtiden. Påverkan på transport av näringsämnen och sediment från fler framtida extrema hydrologiska event kräver ytterligare studier.

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32

Tsai, Hsin-Yao y 蔡心堯. "A study of tidal water level changes by swan model". Thesis, 2006. http://ndltd.ncl.edu.tw/handle/28634032184632576308.

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碩士
國立成功大學
水利及海洋工程學系碩博士班
94
The wind-wave numerical model was broadly applied to wave prediction. A discussion of the effect due to wind, tide, and current is proceeded by SWAN model which the tide and current data are simulated by POM model. The variation of the wave height cause by water level is tested. The variation of the water level is irrelevant to wave height only if the bed is horizontal. In the verification, the path and the intensity of typhoon cause discrepancies between the computational result and the measurement. Considering the effect of current is suggested for the accuracy of SWAN model.

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33

LIN, Ko-Wei y 林克維. "River Water Level Changes to Groundwater Level in the Aquifer Affect Viewing Aquifer Heterogeneous Distribution of Hydrogeological Parameters". Thesis, 2015. http://ndltd.ncl.edu.tw/handle/33jh2h.

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碩士
國立雲林科技大學
環境與安全衛生工程系
103
As source is pumping to influence the groundwater table scant, unless it is largest. Therefore, this study as source is happening river flood. It is usually happen when the heavy raining. Estimated hydrogeological parameters distribution field increased uncertainty when it raining. This study used the rubber dam at New Huwei Creek to let the surface water level change. The surface water level is rising as a river flood event. All of flood events deducted flood event of rainfall than obtain the non-rainfall flood events the hydrogeological heterogeneity distribution field is inversed estimate by river stage tomography method. Finally, groundwater table is predicted at non-rainfall flood events. Before the real field of recharge test analysis, this study do recharge test by the Monte Carlo test. Method architecture about recharge test is established to analysis of heterogeneity hydrogeological parameters distribution field. Then, the real groundwater level data during flood event of non-rainfall to analysis of recharge test. Monte Carlo test results is the more accurate that estimate the distribution of the heterogeneity of hydrogeological parameters near the observation wells. Estimated field is the best by six flood event of non-rainfall, and validation groundwater level is good during the flood event of non-rainfall l. Real field recharge test analysis is better to estimated head by the more flood event of non-rainfall inverse. The result is the L1 (average absolute error) = 0.445 (m), the L2 (root mean square error) = 0.469 (m) and COR (correlation) = 0.545. The error is small and the correlation coefficient is high that it is represents the real field of heterogeneous estimate hydrogeological parameters of the distribution field is correct. Therefore, the River Stage Tomography is available for real field. Keywords: river stage tomography、Rubber dam、New Huwei Cree

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34

"Atomic Level Study of Structural Changes of TiO2 Based Photocatalysts During Solar Water Splitting Reactions Using TEM". Doctoral diss., 2015. http://hdl.handle.net/2286/R.I.36519.

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abstract: Photocatalytic water splitting is a promising technique to produce H2 fuels from water using sustainable solar energy. To better design photocatalysts, the understanding of charge transfer at surfaces/interfaces and the corresponding structure change during the reaction is very important. Local structural and chemical information on nanoparticle surfaces or interfaces can be achieved through characterizations on transmission electron microscopy (TEM). Emphasis should be put on materials structure changes during the reactions in their “working conditions”. Environmental TEM with in situ light illumination system allows the photocatalysts to be studied under light irradiation when exposed to H2O vapor. A set of ex situ and in situ TEM characterizations are carried out on typical types of TiO2 based photocatalysts. The observed structure changes during the reaction are correlated with the H2 production rate for structure-property relationships. A surface disordering was observed in situ when well-defined anatase TiO2 rhombohedral nanoparticles were exposed to 1 Torr H2O vapor and 10suns light inside the environmental TEM. The disordering is believed to be related to high density of hydroxyl groups formed on surface oxygen vacancies during water splitting reactions. Pt co-catalyst on TiO2 is able to split pure water producing H2 and O2. The H2 production rate drops during the reaction. Particle size growth during reaction was discovered with Z-contrast images. The particle size growth is believed to be a photo-electro-chemical Ostwald ripening. Characterizations were also carried out on a more complicated photocatalyst system: Ni/NiO core/shell co-catalyst on TiO2. A decrease of the H2 production rate resulting from photo-corrosion was observed. The Ni is believed to be oxidized to Ni2+ by OH• radicals which are intermediate products of H2O oxidation. The mechanism that the OH• radicals leak into the cores through cracks on NiO shells is more supported by experiments. Overall this research has done a comprehensive ex situ and in situ TEM characterizations following some typical TiO2 based photocatalysts during reactions. This research has shown the technique availability to study photocatalyst inside TEM in photocatalytic conditions. It also demonstrates the importance to follow structure changes of materials during reactions in understanding deactivation mechanisms.
Dissertation/Thesis
Doctoral Dissertation Materials Science and Engineering 2015

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35

Njaya, Friday Jack. "The lake Chilwa fishing household strategies in response to water level changes: migration, conflicts and co-management". Thesis, 2009. http://hdl.handle.net/11394/3204.

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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

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36

Wu, Shu-Fen y 吳淑芬. "The effects of grade level and gender on elementary school students’ conceptual understanding of state changes of water". Thesis, 2015. http://ndltd.ncl.edu.tw/handle/43276962054936183890.

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碩士
國立新竹教育大學
科學教育教學碩士班
103
This study investigates the effects of grade level and gender on elementary school students’ conceptual understanding of state changes of water. This study used a cross-sectional survey method, and the research tools were the achievement test and the diagnostic test of state changes of water. The student samples were from a public elementary school in Taoyuan City. There were 241 students from the fourth grade, 243 students from the fifth grade, and 244 students from the sixth grade, for a total of 728 students (Male/361, Female/367). Data analysis included descriptive statistics, two-way ANOVA and logistic regression. The research results were as below: 1. Grade level had a significant effect on students' achievement of state changes of water, and the higher grade level students had better achievement of state changes of water. 2. Gender had no significant effect on students' achievement of state changes of water. Therefore, there were no significant differences in achievment of state changes of water between girls and boys. 3. Grade level had a significant effect on students’ conceptual understanding of evaporation, condensation and evaporation and condensation in the process of boiling. The higher grade level students had better conceptual understanding of state changes of water. 4. In learning about state changes of water, students had the least difficulty in developing a conceptual understanding of evaporation, while they had more difficulty in conceptual understanding of condensation. The most difficult concepts for students to understand were evaporation and condensation in the process of boiling. 5. Gender had no significant effect on students’ conceptual understanding of evaporation and condensation. However, gender had a significant effect on students’ conceptual understanding of evaporation and condensation in the process of boiling; moreover, boys had better conceptual understanding than girls.

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37

Hsu, Chia-Rung y 許家榕. "Adaptations of an amphibious plant, whorled marsh pennywort (Hydrocotyle verticillata Thunb.), to terrestrial and aquatic environments and changes in water level". Thesis, 2011. http://ndltd.ncl.edu.tw/handle/18460304308890956341.

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碩士
國立臺灣師範大學
生命科學研究所
100
This study examined how morphology and physiology of the amphibious plant, whorled marsh pennywort (Hydrocotyle verticillata Thunb.), respond to changes in aquatic and terrestrial environments and changes in water level. The ratio of stomatal density between upper and lower epidermis shows no significant difference among 3 groups: terrestrial leaf, emergent leaf, and floating leaf. There was also no significant difference in stomatal density of upper or lower epidermis among the 3 groups. The result indicates that these environmental changes do not affect the ratio of stomatal density between upper and lower epidermis of Hydrocotyle verticillata. Net photosynthesis rate(Pn), stomatal conductance(gs), intercellular CO2 concentration(Ci), the chlorophyll fluorescence (Fv / Fm ratio) and petiole length were investigated in cultured plants. After growing the terrestrial individuals in aquatic environment for 3, the Pn increases to 3.71 ± 1.29 μmolCO2‧m-2s-1 from 0.98 ± 0.72 μmolCO2‧m-2s-1. The increment of the terrestrial plants after aquatic treatment is significantly higher than the increment of plants in the control group, possibly due to the increase of the gs and biochemical reactions in the treated group. The Fv/Fm ratio of the terrestrial individuals decreases to 0.61 ± 0.08 from 0.72 ± 0.05, suggesting no increase in biochemical reactions. Thus, the increase in Pn may be related to the increase in the gs of the terrestrial ones. On the contrary, the Pn and the Fv/Fm ratio show no significant difference between the aquatic plants and the aquatic ones after growing under terrestrial environment for 3 weeks. There is no significant change in the gs and the Fv / Fm ratio but there is a significant decrease in Ci following the treatment. Thus, the increase in Pn may be related to the increase in biochemical reactions of the terrestrial ones. Besides, the petiole length of the aquatic plants extends by 57% after 3 weeks treatment with raising water level. The petiole length extension shows significant difference between the high water level ones and the regular water level ones. Apparently the blade can be lifted up vertically to avoid floating or being submerged. It is inferred that Hydrocotyle verticillata maintains proper transpiration and gas exchange by means of adjusting increase of petiole length. In summary, Hydrocotyle verticillata has higher capacity of photosynthesis in aquatic environment. Hydrocotyle verticillata can adapt changing environment of terrestrial, aquatic and even high water level condition with no sign of physiological stress. Hydrocotyle verticillata could grow extensively when facing water logged habitat or changes in water level. Whether or not the wide distribution of Hydrocotyle verticillata could threat the growth or survival of native plant species, and whether or not its distribution is limited by drought, deserve further investigations.

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38

Huang, Shih-Wei y 黃世偉. "Groundwater level variations and special geological phenomena caused by dramatic changes of pore water pressure in central Taiwan during the 1999 Chi-Chi earthquake". Thesis, 2006. http://ndltd.ncl.edu.tw/handle/80643967404307046111.

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博士
國立成功大學
地球科學系碩博士班
94
The 1999 Chi-Chi earthquake on September 21, 1999 (MW=7.3) was caused by the intraplate’s Chelungpu fault rupture, while the 2002 Haulien earthquake on March 31, 2002 (MW=6.8), and the 2003 Chengkung earthquake on December 10, 2003 (MW=6.8), were caused by the dislocation of collision and subduction zone between the Eurasian and Philippine Sea plates. The different earthquake locations, and depths helped us study the effect of an earthquake on the densely distributed groundwater level observation net in the Choshui river alluvial fan of central Taiwan. The scope and extent of the coseismic groundwater level change caused by the 1999 Chi-Chi earthquake was based on the observed groundwater level data for the alluvial fan are more extensive and remarkable than those of the 2002 Hualien and 2003 Chengkung earthquakes. The significantly high amplitude of coseismic surge-type groundwater level changes appeared in the 1999 Chi-Chi earthquake, but did not appear in the 2002 Hualien’s and the 2003 Chengkung’s. A few of the coseismic rise-type groundwater level changes and post-seismic groundwater level changes were seen in the 2002 Hualien’s and 2003 Chengkung’s earthquakes, but were not found in the 1999 Chi-Chi earthquake. Such differences might be caused by distinct earthquake mechanisms and seismic wave propagation path. All of the different groundwater level changes which were observed in the present study suggest that the key parameters, from high to low correlations for Layer 2-1 (a confined to partially unconfined aquifer) in the Choshui river alluvial fan, are the distance from the observation well to the epicenter in the 1999 Chi-Chi earthquake (r=-0.77, p<<0.05, n=37), vertical direction peak ground acceleration (z-PGA, r=0.75, p<<0.05, n=37), and logarithmic hydraulic conductivity (logK, r=-0.35, p=0.036<0.05, n=37). Meanwhile, in general, the coseismic groundwater level change and the arithmetic average of hydraulic conductivity for a well in different depths of aquifers in the alluvial fan have a tendency to decrease from the proximal to distal fans. Our results also revealed that the rate of change in tectonic stress and strain is faster than that of the coseismic groundwater level. In the 1999 Chi-Chi earthquake, unlike a common landslide a particular landslide occurring at Chiu-Fen-Erh-Shan was associated with contemporaneous formation of tektite induced by high frictional heat and large-scale eruptions of rock formations in the adjoining region. The occurrence of pseudotachylyte suggests a low water content in rocks and a high ratio of slip distance to slip-zone thickness so that high heat can be produced to initiate the formation of glassy materials. Evidence for a large-scale rock eruption was observed in the nearby region of the landslide area. Three possible causes of rock eruption are proposed here including: (1) transmission of seismic waves gave rise to relative displacement and high frictional heating that caused vaporization of pore water in association with high seismic acceleration and created fractures and adjoining rock eruption; (2) propagation of seismic waves did not produce relative motion along fractures but built up pressure forcing eruption of pore fluid and rocks; (3) high frictional heat produced by the processes of large-scale landslide increased the temperature and pressure of pore water. The country rocks were uplifted and erupted when the uplift force exceeded the gravity and cementation forces during the period of strong seismic motion. There were different surface deformed styles occurred in the Wufeng and Fengyuen-Shihkang areas, in which the former one is an uplift without significant surface rupture and the latter one is an uplift accompanied with surface rupture. The areas exhibiting different deformations are characterized by different sediment depth, pore pressure and trishear of seismic propagation.

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39

Jaček, Matouš. "Příčiny změn vývoje vybraných fluviálních jezer Lužnice v profilu Základna". Master's thesis, 2018. http://www.nusl.cz/ntk/nusl-388327.

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The aim of this thesis is to evaluate developement of selected lakes in area Základna in upper Lužnice basin. The area of interest is located in nature reservation Horní Lužnice, which extends from state border with Austria to Suchdol nad Lužnicí. This part of the river is very preserved almost without any anthropogenic influence. Eventhough it is the middle part of the river, it has developed floodplain with meandering belt, which is typical for lower parts of rivers. Because of its conditions, this area is very convenient for observing natural spills and studying fluvial lakes, which occure here in huge amount. First part of this work describes characteristic of the study area, fluvial lakes and natural spills and floods in the area. The main second part focuses on research of selected lakes and their developement. During several field researches the lakes were mapped and measured and soil samples were taken from the lake beds. Furthermore flow in floodplain during river spill was measured and data from automatic surface level sensors were evaluated, which show mutual connections of fluctuations of the lakes and the river. In conclusion the results of measurement were compared with previous theses regarding this area. Main results are that common spills cause clogging of lakes but intense floods...

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40

Lu, Hsueh-Chien y 呂學建. "Uncertainty Analysis of Manhole Water Level in Jhong-Gang Drainage System under Climate Change". Thesis, 2012. http://ndltd.ncl.edu.tw/handle/43688465889382808920.

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碩士
中原大學
土木工程研究所
100
This research combines frequency analysis, design storm, and sampling theory to evaluate the uncertainty of the manhole water level in drainage system. The rainfall under climate change is estimated by combining design storm, and frequency analysis. The effect of water level in manholes with uncertainty both from hydrological and geographical parameters of SWMM-RUNOFF and SWMM-EXTRAN module is estimated by Latin Hypercube Sampling (LHS), with 100 sampling size. The rainfall, of 5-year, 25-year, and 100-year return period, events under climate change are generated by Huff method, ranking design storm method with lognormal distribution and Bootstrap random sampling technique (300 Bootstrap samples). Jhong-Gang Drainage System in Xinzhuang district, New Taipei city is employed as a case study. The hourly rainfall data of Taipei weather station, the closest one to case study area, from 1951 to 2011 are collected first. The uncertainty of water level of manholes in case area is then estimated within three cases: 1. only uncertainty of parameters of SWMM is considered, 2. only uncertainty of historical rainfall is considered, and 3. both uncertainties of parameters of SWMM and historical rainfall are considered. The uncertainty for each case is assessed by running 100 times SWMM in which the parameters of SWMM model are generated by LHS. Based on the analyzed results, the uncertainty of water level of S75 manhole in case 3 is lower; of 25-year and 100-year return period, the uncertainty of water level of C66 and C70 manholes is higher in case 1 and case 2.

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41

Stewart, Jordan. "Implications of Low Water Levels for Canadian Lake Huron Marina Operations". Thesis, 2009. http://hdl.handle.net/10012/4901.

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Recreational boating in the Great Lakes is suggested to fuel tourism and the Ontario economy. Like many other tourism sectors, boating-tourism is a highly climate-sensitive economic sector which significantly relies upon compromising climatic conditions. Climate change in the 21st century is projected to alter climatic parameters in the Great Lakes region, thereby generating low lake water conditions and inadequate water levels within some marina facilities that cater to recreational boats. This study examines the multiple implications lakeside marina facilities have previously endured during low water conditions and the possible implications they may experience during three scenarios of water level reductions as a result of climate change. Among the five Great Lakes, Lake Huron has become one of the most prominent lakes for understanding the relationship between climate variability and water-level fluctuations. A questionnaire was administered to 58 marina operators on the Canadian Lake Huron coastline. The questionnaire results were analysed, indicating implications Lake Huron marina operators experienced at their facilities during low water conditions and methods of adaptation that they used to overcome these conditions. The results also projected future implications that may result from climate change and reduced water levels. The most imminent impacts Canadian marina facilities on the Lake Huron coastline would endure as a result of climate change and low water conditions would be the loss of docking slips and potential marina closures. Without adaptation of marina infrastructure, future implications on some Lake Huron Canadian marina facilities may cause substantial economic loss for nearby communities and businesses. Economic losses resulting from lake level water reductions and reduced boat-based expenditures for two regions located on Lake Huron's Georgian Bay shoreline are derived in the study. It is anticipated that the results of this study will provide significant groundwork for systematic and regional evaluations on the impacts in which climate change has upon Great Lake marinas and boat-based tourism.

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42

Lin, Wei-Nan y 林威男. "Experimental measurements of mechanical strain, temperature change and water level using fiber Bragg grating sensors". Thesis, 2011. http://ndltd.ncl.edu.tw/handle/53957212649563449277.

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碩士
元智大學
機械工程學系
99
Basing on the shift of Bragg wavelength, fiber Bragg grating sensors (FBG) have been developed to measure a variety of physical parameters such as stress, strain, displacement, temperature, vibration and pressure. In this work, the FBG was connected to an optical spectrum analyzer (OSA) to measure the mechanical strain and temperature change simultaneously. The measuring results were validated with the strain gauge and thermal couple. In order to measure the dynamic responses, the FBG was incorporated with the optical filter and photo detector to convert the shift of Bragg wavelength to a change of light intensity. The experimental tests of dynamic three point bending test, dynamic four point bending test and free vibration test of a cantilever beam were presented to demonstrate the capability of measuring dynamic responses using FBG sensors. Finally, the FBG sensor was used to monitor the water level subjected to a wave motion.

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43

Walker, Gillian Sarah. "Effects of climate variability and change on surface water storage within the hydroclimatic regime of the Athabasca River, Alberta, Canada". Thesis, 2016. http://hdl.handle.net/1828/7253.

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Warmer air temperatures projected for the mid-21st century under climate change are expected to translate to increased evaporation and a re-distribution of precipitation around the world, including in the mid-latitude, continental Athabasca River region in northern Alberta, Canada. This study examines how these projected changes will affect the water balance of various lake sizes. A thermodynamic lake model, MyLake, is used to determine evaporation over three theoretical lake basins – a shallow lake, representative of perched basins in the Peace-Athabasca Delta near Fort Chipewyan; an intermediate-depth lake representative of industrial water storage near Fort McMurray; and a deep lake representative of future off-stream storage of water by industry, also near Fort McMurray. Bias-corrected climate data from an ensemble of Regional Climate Models are incorporated in MyLake, and the water balance is completed by calculating the change in storage as the difference between precipitation and evaporation. Results indicate that evaporation and precipitation are projected to increase in the future by similar magnitudes, thus not significantly changing the long-term water balance of the lakes. However, intra-annual precipitation and evaporation patterns are projected to shift within the year, changing seasonal water level cycles, and the magnitudes and frequencies of extreme 1-, 3- and 5-day weather events are projected to increase. These results demonstrate that future climate change adaptation and mitigation strategies should take into account increases in intra-annual variability and extreme events on water levels of lakes in mid-latitude, interior hydroclimatic regimes.
Graduate
0368
walkerg@uvic.ca

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44

Lin, Tzu-Yang y 林子揚. "Temporal and Spatial Changes in The Water Levels of Shallow Wells in The Caiyuan Area". Thesis, 2019. http://ndltd.ncl.edu.tw/handle/pk68k9.

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碩士
國立澎湖科技大學
觀光休閒系碩士班
107
Surrounded by the most well-developed water source in Penghu, Caiyuan has 28 wells in addition to the original Double Lake Park water source. Although such a large number of water resources exist in the Caiyuan area, there isn’t any general survey data available to explain how this number came about, and the causes that affect the area’s groundwater level and pattern of change have yet to be described. This study aims to explore the distribution of wells and water level changes in the Caiyuan area through drone photogrammetry, ground GPS measurements, literature review, and field surveys. Through field investigation, wells in the surrounding area of Caiyuan were located. The data were analyzed to find the relationship between the groundwater level and a variety of variables in the Caiyuan area. The data consisting of water level changes and the period observation variables were then examined to identify connections. Accordingly, the patterns that affect the groundwater level change in the Caiyuan area can be found via these various data points. After using drone photogrammetry to establish a high-precision and high-spatial-resolution numerical model, and analyzing the measurements of groundwater level changes of the wells, it is found that the change of the groundwater level is not completely consistent with the terrain. The northwest end higher than the northeast end and the southeast end higher than groundwater pattern in the Caiyuan area presents a U-shaped trend, with the the southwest end. The water accumulates starting in the northeast and proceeding to the southwest. The results demonstrate that the rainfall has significant effects on the groundwater level change in the Caiyuan area, exhibiting a positive correlation. When the rainfall intensity reaches a certain level, the ascent rate of the water level slows down, and the water level of the wells in use descends faster than those of the wells not in use. Significant differences in the water level change were observed among wells of different heights.The higher the water level, the more sensitive and greater the change is; significant differences were observed among the water level changes caused by the surrounding environment, and the water level of the well in mud terrain descends faster than the water level of the cement terrain.

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45

Ramlal, Kristie Anuradha. "Controls on late Neogene deep-water slope channel architecture in a bathymetrically complex seafloor setting : a quantitative study along the Southeastern Caribbean Plate Margin, Columbus Basin, Trinidad". 2013. http://hdl.handle.net/2152/23230.

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Slope-channels act as conduits that transport sediments from the shelf staging area to the basin floor. The Pliocene-Pleistocene section of the Columbus Basin in the deep-water slope offshore eastern Trinidad provides an opportunity to study slope-channel morphology and evolution, as well as any association between deep-water deposits, palaeo-seafloor bathymetry, shelf sediment feeder mechanism and changes in sediment supply types and volumes. Approximately 3250 km2 of 3D seismic data allow imaging and interpretation of channels within an interval between two regional surfaces termed P30 and P40. Observations of seismic cross-sections and stratal slices reveal a number of features including channels, mud diapirs, mass transport deposits (MTDs), and faulted anticlinal ridges. Channels appear leveed and unleveed, and alternate with MTDs in a cyclic vertical succession. Nineteen channels were mapped and divided into two groups based on their degree of levee development and stratigraphic position relative to MTDs. Group 1 channels, positioned below MTDs near the base of the interval, are shallowly incised, and show limited levee development. Group 2 channels, situated above MTDs, are relatively deeply incised, and have comparatively larger, well-developed levees throughout their lengths. Morphometric data from these channel groups reveal significant variability in channel width, channel depth, meander belt width, and sinuosity downslope. This variability is associated with influences of temporally equivalent local features and regional sea-floor slope changes. Increased slope gradient causes a marked increase in sinuosity. Diapirs and anticlinal ridges confine channel paths, divert their flow, and cause post-depositional deformation of both levees and channels. Levee height decreases downslope while levee width shows considerable asymmetry, which is related to occurrences of mud diapirism and MTDs. Irregularities on the upper surface of MTDs create accommodation space that confines turbidity flows, enabling ponding of sediments and volumetrically large levee construction. This accounts for dispersion of turbidity flows below the MTD which creates a series of small channels spread over a wide area, and comparatively fewer, confined channels above the MTDs with large levees.
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46

Ndlela, Bekithemba. "Impact of climate change on fresh water resources of Elliot town in the Eastern Cape". Diss., 2015. http://hdl.handle.net/10500/20157.

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Climate change and variability have great impact on the hydrological cycle and consequently on the availability of water resources. Variations in temperature and precipitation trends that are occurring are a consequent of the increase in the concentrations of greenhouse gases, which are subsequently affecting the hydrological cycle. This in turn affects water quantity and quality, which is essential for agriculture, domestic and industrial uses. This study, done in Elliot Town and the surrounding areas of Sakhisizwe Municipality in the Eastern Cape Province of South Africa, evaluates how climate change and variability is affecting water availability and its quality in the town. The impact climate change and variability on agricultural production is also assessed. Remote Sensing, Geographic Information Systems (GIS), databases and some statistical packages have been used to collect, analyse and create spatial maps used to derive concrete conclusions. The methods used aided in spatially analysing the changes in temperature and rainfall along the years and make a comparative analysis. The study has shown that the spatial changes in the amount, intensity and frequency of rainfall affects the magnitude and frequency of stream flows; consequently, increasing the intensity of floods and droughts that have been recurring in the last few decades. The municipality is more affected by climate variability than change, and the resultant extreme climate events are affecting the water resources resulting in domestic water cuts, poor water quality and low agriculture productivity. This study recommends the importance of an awareness campaigns on climate change and variability and their effect directed towards the community, especially on novel water harvesting technologies. The study also highlights the importance of a robust early warning system to prepare the community in case of a climate shock, which is an area that needs further research.
Environmental Sciences

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47

Grothe, Steffen [Verfasser]. "Integrated water resources management and institutional change in Vietnam and Poland : a comparative analysis with special consideration of the river basin level / vorgelegt von Steffen Grothe". 2009. http://d-nb.info/1001384369/34.

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48

Beaton, Andrew. "Testing and Refining a Unique Approach for Setting Environmental Flow and Water Level Targets for a Southern Ontario Subwatershed". Thesis, 2012. http://hdl.handle.net/10214/3850.

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In this study Bradford’s (2008) approach for setting ecological flow and water level targets is tested and refined through application within the Lake Simcoe Region Conservation Authority’s (LSRCA) subwatershed of Lover’s Creek. A method for defining subwatershed objectives and identifying habitat specialists through expert input is proposed and tested. The natural regime of each streamflow and wetland site is characterized along with the hydrological alteration at each site. Potential ecological responses to the hydrologic alterations are then hypothesized for the different types of changes calculated at each site. Methods for setting overall ecosystem health and specific ecological objective flow targets are proposed and tested. These targets are integrated into a flow regime for each site and a process for using this information for decision making is suggested. Flow magnitude quantification is attempted using hydraulic modelling and sediment transport equations, however the data used were found to be inadequate for this application. The accuracy of the targets developed using the method presented in this paper is mainly limited by the accuracy of the hydrological model and quantified flow magnitudes. Recommendations for improving these components of the assessment are made. The unique approach and recommendations presented in this paper provide explicit steps for developing flow targets for subwatersheds within the LSRCA. This research contributes toward the advancement of EFA within the LSRCA, which provides opportunity for enhanced protection and restoration of ecosystem health across the watershed.
Lake Simcoe Region Conservation Authority

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49

Danner, Allison G. "Will we need to change the rules : assessing the implications of climate change for dam operations in Oregon's McKenzie River Basin". Thesis, 2013. http://hdl.handle.net/1957/38119.

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Dams and reservoirs are important components of water resource management systems, but their operational sensitivity to streamflow variability may make them vulnerable to climate change. Climate change is likely to affect the magnitude and timing of streamflow, motivating the assessment of potential impacts on dams and reservoirs. Here I examine a case study of Cougar Dam, a multipurpose dam in Oregon, USA, to assess potential impacts of future climate change on operational performance. In the first portion of this study, I examine the historical operation of Cougar Dam, to understand (1), whether operational objectives have been achievable in the past despite operational variability, and (2) how climatic variation is expressed in operational trajectories. By analyzing historical streamflow and operations data using a set of metrics, I characterize variability in past operations and how that variability relates to streamflow. I also employ a reservoir model to distinguish operational differences due to streamflow variability from variability due to other factors that affect operations. I find that operational objectives have been achievable, despite variability in operations and departures from the ideal operational trajectory. Throughout the historical period, flood control operations have almost always kept reservoir outflows below the desired maximum outflow. Although filling occurs 9 days late on average, the reservoir has filled in all but 6 out of 37 years. Although drawdown occurs 47 days early on average, early drawdown does not generally impact recreation and allows minimum outflows to be met every day during all but the driest year. I also find that total seasonal inflow is correlated with measures of operational performance, and that other factors besides climate play an important role in determining operational trajectories. I conclude that operations of Cougar Reservoir are vulnerable to climate change, but that operational flexibility may mitigate some of the potential impacts. In the second portion of this study I assume that current operating rules will be kept in place and I aim to understand what types of operational impacts may be expected, when they may be expected to occur, and whether the operational impacts may necessitate changing operational rules. I employ both a traditional climate impacts assessment approach to assess changes over time as well as a scenario-neutral approach to generalize relationships between streamflow and operations of Cougar Dam. I find that projected increases in winter streamflow could result in up to twice the number of downstream high flows than in the past and that projected decreases in summer streamflow could result in earlier reservoir drawdown by up to 20 days on average. Additionally, filling of the reservoir may occur up to 16% more often or 11% less often than in the past, depending on spring flow magnitude and timing. I also find that there are strong general relationships between total inflow volume and flood control performance, and that there are total inflow thresholds for whether or not the reservoir will fill or will be full enough for recreation in late summer. I conclude that future modification of operating policies may be warranted, but that there will likely be tradeoffs between operating objectives in the future even if operating rules are modified.
Graduation date: 2013

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50

Zamora-Arroyo, Jose Francisco. "Impacts of instream flows on the Colorado River Delta, Mexico : spatial vegetation change analysis and opportunities for restoration". Thesis, 2002. http://hdl.handle.net/1957/31139.

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Until the 1930s, flows of the Colorado River maintained approximately 781,060 hectares of wetlands in its delta. These wetlands provided important feeding and nesting grounds for resident and migratory birds as well as spawning and protection habitat for many fish and other invertebrate species. However, the Delta's wetlands started to disappear as water was used for agricultural and urban uses in the United States and Mexico. The 1944 United States-Mexico water treaty, which allocates 1.8 million m��/year to Mexico, did not define a minimum flow to maintain the Delta's ecosystems. The resulting degraded Delta lead to the perception in the 1980s that the Delta was a dead ecosystem. This study investigates whether this "dead Delta" perception is valid. Its central hypothesis is that regenerated vegetation in riparian and flood plain zones is associated with surplus river flows during the 1990s. A vegetation analysis, using satellite imagery and field methods, shows that native trees have regenerated during the last 20 years, and now account for 23% of vegetation in a 100 km, non-perennial, stretch of river below the United States-Mexico border. A spatial trend analysis using multi-temporal data on percent vegetation cover indicates that there are 6,320 hectares that show a significant increasing trend (p-value<0.05) in vegetation cover, with the Delta's riparian zone having at least 18% of its area showing this trend. The study estimates that once in four years February to April flow of 300 million m�� (at 80-120 m��/s) is sufficient to germinate and establish new cohorts of native trees, and highlights the need for smaller but more periodic flows in order to maintain wetland areas. It is concluded that there is clear evidence of the resilience of the Delta's ecosystems and that the "dead Delta" perception is no longer valid. There exist critical habitat in the Delta that needs to be protected, while there also exist short and long term opportunities to ecologically enhance and expand current habitat. Hydrological and ecological studies are needed to estimate specific water requirements for these areas in order to efficiently target them for immediate and long term conservation actions.
Graduation date: 2003

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Tesis sobre el tema "Water level changes"

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