Rozprawy doktorskie na temat „Hydrology|Climate Change”
Kliknij ten link, aby zobaczyć inne rodzaje publikacji na ten temat: Hydrology|Climate Change.
Utwórz poprawne odniesienie w stylach APA, MLA, Chicago, Harvard i wielu innych
Sprawdź 50 najlepszych rozpraw doktorskich naukowych na temat „Hydrology|Climate Change”.
Przycisk „Dodaj do bibliografii” jest dostępny obok każdej pracy w bibliografii. Użyj go – a my automatycznie utworzymy odniesienie bibliograficzne do wybranej pracy w stylu cytowania, którego potrzebujesz: APA, MLA, Harvard, Chicago, Vancouver itp.
Możesz również pobrać pełny tekst publikacji naukowej w formacie „.pdf” i przeczytać adnotację do pracy online, jeśli odpowiednie parametry są dostępne w metadanych.
Przeglądaj rozprawy doktorskie z różnych dziedzin i twórz odpowiednie bibliografie.
1
Serrat, Capdevila Aleix. "Climate Change Impacts in Hydrology: Quantification and Societal Adaptation". Diss., The University of Arizona, 2009. http://hdl.handle.net/10150/194702.
Streszczenie:
The research presented here attempts to bridge science and policy through the quantification of climate change impacts and the analysis of a science-fed participatory process to face a sustainability challenge in the San Pedro Basin (Arizona). Paper 1 presents an assessment of a collaborative development process of a decision support system model between academia and a multi-stakeholder consortium created to solve water sustainability problems in a local watershed. This study analyzes how science-fed multi-stakeholder participatory processes lead to sustainability learning promoting resilience and adaptation. Paper 2 presents an approach to link an ensemble of global climate model outputs with a hydrological model to quantify climate change impacts in the hydrology of a basin, providing a range of uncertainty in the results. Precipitation projections for the current century from different climate models and IPCC scenarios are used to obtain recharge estimates as inputs to a groundwater model. Quantifying changes in the basin's water budget due to changes in recharge, evapotranspiration (ET) rates are assumed to depend only on groundwater levels. Picking on such assumption, Paper 3 explores the effects of a changing climate on ET. Using experimental eddy covariance data from three riparian sites, it analyzes seasonal controls on ET. An approach to quantify evapotranspiration rates and growing season length under warmer climates is proposed. Results indicate that although atmospheric demand will be greater, increasing pan and reference crop evaporation, ET rates at the studied field sites will remain unchanged due to stomatal regulation. However, the length of the growing season will increase, mainly with an earlier leaf-out and at a lesser level by a delayed growing season end. These findings - implying decreased aquifer recharge, increased riparian water use and a lesser water balance - are very relevant for water management in semi-arid regions. Paper 4, in which I am second author, explores the theory relating changes in area-average and pan evaporation. Using the same experimental data as Paper 3, it corroborates a previous theoretical relationship and discusses the validity of Bouchet's hypothesis.
2
Hackett, William. "Changing Land Use, Climate, and Hydrology in the Winooski". ScholarWorks @ UVM, 2009. http://scholarworks.uvm.edu/graddis/99.
Streszczenie:
This study analyzes temporal trends and periodicity in seventy years of publicly available stream discharge and climate data for the Winooski River Basin of northern Vermont as well as lake level data for adjacent Lake Champlain. We also use random sampling and manual, point-based classification of recent and historical aerial imagery to quantify land use change over the past seventy years in the 2,704 km2 Winooski River Basin of northern Vermont. We find a general increase in annual precipitation, discharge, and mean lake level with time in the basin; discharge increases 18% over the period of record while precipitation increases by 14%. Over the last 70 years, mean annual temperature has increased at the Burlington Vermont station by 0.78 degrees Celsius (1.4 degrees Fahrenheit). Four sets of aerial photographs, taken at intervals of 12 to 29 years between 1937 and 2003 at thirty randomly selected sites, demonstrate that actively cleared land area has decreased by 14%, while forested land and impervious surfaces increased by 10% and 5%, respectively. Spectral analysis of precipitation, discharge and lake level data show a ~7.6 year periodicity, which is in phase with the North Atlantic Oscillation (NAO); higher than average precipitation and discharge are most likely when the NAO is in a positive mode. The NAO relationship demonstrates that discharge is largely controlled by precipitation; anthropogenic changing climate and changing land use over the past 70 years appear to have subtly changed the seasonality of discharge and caused an increase in base flow.
3
Larson, Robert, i University of Lethbridge Faculty of Arts and Science. "Modelling climate change impacts on mountain snow hydrology, Montana-Alberta". Thesis, Lethbridge, Alta. : University of Lethbridge, Faculty of Arts and Science, 2008, 2008. http://hdl.handle.net/10133/669.
Streszczenie:
A modelling approach focused on snow hydrology was developed and applied to project
future changes in spring streamflow volumes in the St. Mary River headwaters basin,
Montana. A spatially distributed, physically-based, hydrometeorological and snow mass
balance model was refined and used to produce snow water equivalent (SWE) and
rainfall surfaces for the study watershed. Snowmelt runoff (SR) and effective rainfall
runoff (RR) volumes were compiled for the 1961-2004 historical period. A statistical
regression model was developed linking spring streamflow volume (QS) at Babb,
Montana to the SR and RR modelled data. The modelling results indicated that SR
explained 70% of the variability in QS while RR explained another 9%.
The model was applied to climate change scenarios representing the expected range of
future change to produce annual QS for the period 2010-2099. Compared to the base
period (1961-1990), average QS change ranged from -3% to -12% for the 2020s period.
Percent changes increased to between -25% and -32% for the 2050s, and -38% and -55%
for the 2080s. Decreases in QS also accompanied substantial advances in the onset of
spring snowmelt. Whereas the spring pulse onset on average occurred on April 8 for the
base period, it occurred 36 to 50 days earlier during the 2080s. The findings suggest that
increasing precipitation will not compensate for the effects of increasing temperature in
watershed SWE and associated spring runoff generation. There are implications for
stakeholder interests related to ecosystems, the irrigation industry, and recreation.xii, 136 leaves : ill. ; 28 cm. --
4
Parry, Louise Margaret. "Monsoon variability, climate change and impacts on hydrology in the Himalaya". Thesis, University of Bristol, 2016. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.715813.
5
Booth, Andrew. "Impacts of desiccation cracking and climate change on highway cutting hydrology". Thesis, Loughborough University, 2014. https://dspace.lboro.ac.uk/2134/14825.
Streszczenie:
Climate change is predicted to have a global effect on temperatures and precipitation rates throughout the world. The UK Climate projections expect that in the United Kingdom this will lead to warmer, drier summers and wetter winters, where events of extreme rainfall are more common. These changes are expected to impact on slope hydrology, and concurrently slope stability. In the United Kingdom this impact is expected to be negative, whereas in other countries, such as Italy and France it could lead to slopes being more stable. Infrastructure slopes in the UK range in age and construction quality, they are susceptible to serviceability problems, characterised by heterogeneous material properties and can fail unexpectedly due to progressive reduction in soil shear strength. In this thesis the effects of climate change on a highway cutting in the south of England are modelled, using numerical methods. A finite element model is created and developed in the software package GeoStudio VADOSE/W. The model has been validated against observed pore water pressure trends and magnitudes and is shown to be able to accurately replicate the behaviour. By incorporating the effects of desiccation cracking on the soil s material properties, by the means of bimodal soil water characteristic curve and hydraulic conductivity function, the replication of these trends is improved even further. A series of future climate series were created using the UKCP09 Weather Generator 2.0. These series were implemented with the VADOSE/W model as climate boundary conditions and models were run, and the results compared to control, current climate results. The results were investigated by the means of statistical analyses which revealed that climate change will have some significant effects on the slope s hydrology, increasing magnitudes of evapotranspiration greatly which can have further significant effects on the magnitude of suctions developing in the slope throughout the summer. It is thought that the results suggest that climate change will not have significant negative effects on slope stability. However it is important to remember that the results only apply with certainty to the specific slope and climate change scenario investigated here. The methods used and developed within this thesis can be extended to other locations, in the UK and internationally, analysing the effects of different climate change scenarios.
6
Wherry, Susan Amelia. "Climate Change Effects and Water Vulnerability in the Molalla Pudding River Basin, Oregon, USA". Portland State University, 2013.
7
Culbertson, Andreas Mitsutoshi. "Effects of climate change on Maumee River basin hydrology and nutrient runoff". The Ohio State University, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=osu1437226063.
8
Siam, Mohamed S. "Assessing impacts of climate change on the hydrology of the Nile River". Thesis, Massachusetts Institute of Technology, 2016. http://hdl.handle.net/1721.1/104328.
Streszczenie:
Thesis: Ph. D., Massachusetts Institute of Technology, Department of Civil and Environmental Engineering, 2016.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 179-194).
The human population living in the Nile basin is projected to double by 2050, approaching one billion. The increase in water demand associated with this burgeoning population fuels an ongoing water conflict between the riparian countries. Uncertainty regarding potential future changes in the flow of the Nile River as a result of climate change adds further stress to this critical situation. In this thesis, we investigate the impacts of climate change on hydrology and climate of the Nile basin. In particular, we predict and explain the future changes in interannual variability and long-term mean of the flow in Nile river. We analyze observations on recent change in the flow regime. First, we examine the role of El Niño Southern Oscillation (ENSO) in shaping the interannual variability of the flow in the Nile river. We document an association between variability of ENSO and interannual variability in the flow of the Nile river. We provide a physically-based explanation of this teleconnection. Then, we build on this teleconnection and future predications regarding the frequency of El Niño and La Nina events to project enhancement in future variability of the flow in the Nile river. Second, an improved version of the MIT Regional climate model (MRCM) is used to investigate the future changes in the long-term mean flow in the Nile river. The new version of MRCM includes new parameterizations of large scale cloud and rainfall developed as part of this thesis, which significantly improved the simulation of clouds coverage and radiation at the surface under current climate conditions. The updated version of the model is forced with modified lateral boundary conditions and greenhouse gas concentrations that are assumed to describe future conditions. The impacts on the rainfall over the basin due to local and regional changes in concentration of atmospheric gases are compared to those due to global changes in the humidity and temperature. The numerical simulations using MRCM suggest that increasing humidity at the lateral boundaries due to global processes would enhance the large scale rainfall, particularly during the rainy season. However, air temperature becomes warmer aloft due to the same global processes, which would tend to stabilize the atmosphere and reduce convective rainfall. On the other hand, increasing the concentration of greenhouse gases at local and regional scales would destabilize the vertical profile of air temperature, by increasing the air temperature in the middle and lower atmospheric layers, and hence would enhance convective rainfall. Based on the conclusions of this thesis, the long-term mean and standard deviation of the annual flow in the Nile river are projected to increase for the future period (2000-2100) compared to the past period (1900-2000) by approximately 15% and 50%, respectively. Although the increase in long-term mean of the annual flow should slightly reduce the water stress in the Nile basin, additional water storage capacity in the basin would be needed in order to benefit from the expected additional water in the future.
by Mohamed S. Siam.
Ph. D.
9
Guilbert, Justin. "The Impacts Of Climate Change On Precipitation And Hydrology In The Northeastern United States". ScholarWorks @ UVM, 2016. http://scholarworks.uvm.edu/graddis/646.
Streszczenie:
Shifting climatic regimes can increase or decrease the frequency of extreme hydrologic events (e.g., high and low streamflows) causing large societal and environmental impacts. The impacts are numerous and include human health and safety, the destruction of infrastructure, water resources, nutrient and sediment transport, and within stream ecological health. It is unclear how the hydrology of a given region will shift in response to climate change. This is especially the case in areas that are seasonally snow covered as the interplay of changing temperature, precipitation, and resulting snowpack can lead to an increased risk of flood or drought.
This research aimed to understand the ways temperature and precipitation are changing using general circulation models and observed weather station data in the northeastern United States. With the knowledge that general circulation models do not accurately represent precipitation statistics and trends from the historical period, a large network of climate stations was utilized to further investigate shifts in precipitation. A hydrology model was utilized for further study of regional hydrology. The model used was the Regional Hydro-Ecologic Simulation System, which was calibrated to snow coverage and streamflow for a historical time period. The hydrology model was used to investigate the relationship of snow and streamflow in a changing climate.
We characterized climate change and related impacts in the northeastern United States and estimated a decrease in snowfall of 50% and the number of days below freezing by 45 days by the end of the century. We also showed that precipitation is not only becoming more intense, but it is also more persistent -- a finding that may have significant hydrological implications including increased flood risk throughout the year. The 95th percentile of daily precipitation has increased by 0.5 mm per day per decade, while the probability of successive days with precipitation increased by 0.6 percent per decade. We also explored the role of snowpack in a changing climate. We found that temperature plays a larger role than precipitation in shifting hydrologic regime, because the warming-induced reduction of snowpack reduced the maximum flows more than the increasing precipitation increased the maximum flows. However, because of the increasing intensity and persistence of precipitation, instantaneous peak flows occurring outside of the snowmelt season will likely continue to increase during all times of the year. We shed light on the complexity of the modes of climate change and the interactions that increases in temperature and precipitation can have on the hydrology of a region.
10
Stastney, Phil. "Examining the relationships between Holocene climate change, hydrology, and human society in Ireland". Thesis, University of Reading, 2015. http://centaur.reading.ac.uk/48052/.
Streszczenie:
This thesis explores human-environment interactions during the Mid-Late Holocene in raised bogs in central Ireland. The raised bogs of central Ireland are widely-recognised for their considerable palaeoenvironmental and archaeological resources: research over the past few decades has established the potential for such sites to preserve sensitive records of Holocene climatic variability expressed as changes in bog surface wetness (BSW); meanwhile archaeological investigations over the past century have uncovered hundreds of peatland archaeological features dating from the Neolithic through to the Post-Medieval period including wooden trackways, platforms, and deposits of high-status metalwork. Previous studies have attempted to explore the relationship between records of past environmental change and the occurrence of peatland archaeological sites reaching varying conclusions. More recently, environmentally-deterministic models of human-environment interaction in Irish raised bogs at the regional scale have been explicitly tested leading to the conclusion that there is no relationship between BSW and past human activity. These relationships are examined in more detail on a site-by-site basis in this thesis. To that end, testate amoebae-derived BSW records from nine milled former raised bogs in central Ireland were produced from sites with known and dated archaeological records. Relationships between BSW records and environmental conditions within the study area were explored through both the development of a new central Ireland testate amoebae transfer function and through comparisons between recent BSW records and instrumental weather data. Compilation of BSW records from the nine fossil study sites show evidence both for climate forcing, particularly during 3200-2400 cal BP, as well as considerable inter-site variability. Considerable inter-site variability was also evident in the archaeological records of the same sites. Whilst comparisons between BSW and archaeological records do not show a consistent linear relationship, examination of records on a site-by-site basis were shown to reveal interpretatively important contingent relationships. It is concluded therefore, that future research on human-environment interactions should focus on individual sites and should utilise theoretical approaches from the humanities in order to avoid the twin pitfalls of masking important local patterns of change, and of environmental determinism.
11
Young, Daniel Stuart. "Peatland hydrology, climate change and human societies in Middle and Late Holocene Ireland". Thesis, University of Reading, 2017. http://centaur.reading.ac.uk/73800/.
Streszczenie:
This thesis presents the results of an investigation of the relationships between peatland hydrology, climate change and human activity in the raised bogs of Ireland. In recent decades raised bogs have been shown to be valuable terrestrial archives of both climate change and archaeological activity for the Middle and Late Holocene, revealing evidence for significant centennial scale climate variability and abrupt climate events. However, recent compilations of palaeohydrological records from such sites have revealed evidence for significant inter-site (potentially autogenic) variability, particularly at the decadal to centennial scales thought to have had the most significant impact on human societies. Whilst recent investigations have revealed some evidence for a relationship between peatland hydrology and human activity at individual sites, broader patterns have been inconclusive, leading to the conclusion that the timing and extent of peatland use was not climatically-determined. The palaeohydrology of ten raised bogs in central Ireland has been reconstructed using plant macrofossil analysis, providing a reconstruction of changes in bog surface wetness (BSW) (driven by summer precipitation and temperature). These palaeohydrological records have been compared to site-specific and broader Ireland-wide archaeological datasets in order to examine the evidence for a predictable, consistent relationship between human activity and BSW. The palaeohydrological records are indicative of a combination of both local variability and climatic forcing; however, using the 'time-window' approach the data has provided evidence for regional transitions to wetter conditions indicative of climate forcing at ca. 3400, 2800, 1200 and 350 cal BP. Comparison of the palaeohydrological and archaeological datasets indicates that at individual sites, human activity was more likely to occur in drier bogs. However, no clear linear relationship between climate change and human activity at the broader regional/sub-regional scales could be identified. The apparent contradictions between the interpretation of the data at regional/sub-regional and local scales highlight the issues of chronological uncertainty and local variability in both archaeological and palaeohydrological records. It was therefore concluded that investigations of human-environment interactions should examine these relationships on a site-by-site basis, in order to provide a more detailed understanding of the complex relationships between human activity in peatlands, local environmental conditions and regional climate change.
12
Zulkafli, Zed Diyana. "The hydrology of the Peruvian Amazon river and its sensitivity to climate change". Thesis, Imperial College London, 2014. http://hdl.handle.net/10044/1/23939.
Streszczenie:
This PhD thesis explores the utility of a land surface model (Joint UK Land-Environment Simulator, JULES) for large-scale hydrological modelling of the Peruvian Amazon - a humid tropical mountain basin where process understanding is poor and data are scarce. A sparse rain gauge network necessitates the use of large-scale data from satellite and global climate model reanalysis to complement ground observations, commanding a closer look at (1) the uncertainties (2) merging techniques to utilise multiple observations in the model forcing. A main outcome of the research is establishing the model's sensitivity to precipitation error, and at the same time, demonstrating an increasing reliability of global remote sensing products as model forcing, specifically, with data from the Tropical Rainfall Measuring Mission Multisatellite Precipitation Analysis version 7 algorithm. Furthermore, satellite-rain gauge data assimilation techniques such as mean-bias correction, double smoothing residual blending, and Bayesian combination, are shown to reduce the mean errors in the satellite-based product. Secondly, with regional calibration and an offline runoff routing scheme, JULES is shown to be reasonably skillful at reproducing the observed streamflow dynamic and extremes. Representing the subgrid heterogeneity of soil moisture using the probability distributed model (PDM) was key to improving surface runoff generation. However, evapotranspirative fluxes in the lower basin remain poorly reproduced without an adequate floodplain system representation. Finally, under the Intergovernmental Panel for Climate Change's RCP4.5 future climate scenario, which projects a warming and wetting up to the year 2035, the Peruvian Amazon basin is shown to respond nonlinearly to the increase in wet season precipitation with more than 40% increase in the peak flows compared to the baseline scenario. There is limited confidence in the projections due to climate projections uncertainty and the assumptions of model stationarity.
13
Putman, Annie L. "Tracking the moisture sources of storms at Barrow, Alaska| Seasonal variations and isotopic characteristics". Thesis, Dartmouth College, 2014. http://pqdtopen.proquest.com/#viewpdf?dispub=1553179.
Streszczenie:
Enhanced warming and increasingly ice-free Arctic seas affect Arctic precipitation. We investigate increased Arctic precipitation due to declining sea ice by relating variations in moisture sources to stable isotope compositions of precipitation. We develop a novel method for deriving moisture sources using condensation profiles derived from cloud radar measurements to formulate initial heights for air mass back trajectories. This method was used to locate the moisture sources of seventy Barrow, AK storm events between 2009 and 2013. Trajectories were calculated by NOAA's HYSPLIT, using GDAS reanalysis wind fields. We demonstrate that the moisture source migrates with season, from distal in winter to proximal in summer. Moisture source dew point exhibits a semiannual cycle, with summer and winter maxima. The spring minimum reflects the reintroduction of the Arctic source. The autumn dew point minimum reflects pre-ice ocean cooling locally. 36% of isotopic variation is statistically explained by a combination of the moisture source dew point and trajectory cooling. Transport distance and path both influence the best descriptor of isotopic composition. For local events, dew point is the stronger influence on isotopic composition, explaining 21% of variance. For distal events, the effects of trajectory cooling supersedes the moisture source signal. The orographic effect of the Alaskan and Brooks ranges account for the influence of trajectory path on isotopic composition. Local moisture events during transition seasons were slightly enriched relative to distal events. If we measure further isotopic enrichment during future transition seasons, it may reflect increased contributions from the Arctic source and thus precipitation increase. Deuterium excess reflects various combinations of latitude, sea surface temperature and relative humidity. Moisture source dew point significantly but weakly predicts storm-specific d-excess. Similar analyses can be performed across the Arctic if reanalysis data can generate reliable condensation profiles. To evaluate the efficacy of condensation profiles produced by reanalysis data, we compared the condensation profiles derived from cloud radar to those from reanalysis. On average, reanalysis produced condensation profiles with mean cloud height 1.4 times higher than those from cloud radar. The greater elevation bias translated into a more distal, and thus warmer and drier, moisture source.
14
Rajagopal, Seshadri. "Assessing Water Management Impacts of Climate Change for a Semi-arid Watershed in the Southwestern US". Diss., The University of Arizona, 2012. http://hdl.handle.net/10150/228475.
Streszczenie:
Water managers for the City of Phoenix face the need to make informed policy decisions regarding long-term impacts of climate change on the Salt-Verde River basin. To provide a scientifically informed basis for this, we estimate the evolution of important components of the basin-scale water balance through the end of the 21st century. Bias-corrected and spatially downscaled climate projections from the Phase-3 Coupled Model Intercomparison Project of the World Climate Research Programme were used to drive a spatially distributed variable infiltration capacity model of the hydrologic processes in the Salt-Verde basin. From the many Global Climate Model's participating in the IPCC fourth assessment, we selected a five-model ensemble, including three that best reproduce the historical climatology for our study region, plus two others to represent wetter and drier than model average conditions; the latter two were requested by City of Phoenix water managers to more fully represent the full range of GCM prediction uncertainty. For each GCM, data for three emission scenarios (A1B, A2, B1) was used to drive the hydrologic model into the future. The model projections indicate a statistically significant 25% decrease in streamflow by the end of the 21st century. Contrary to previous assessments, this is not caused primarily by changes in the P/E ratio, but is found to result mainly from decreased winter precipitation accompanied by significant (temperature driven) reductions in storage of snow. The results show clearly the manner in which water management in central Arizona is likely to be impacted by changes in regional climate.
15
Tsarouchi, Georgia-Marina. "Modelling land-use and climate change impacts on hydrology : the Upper Ganges river basin". Thesis, Imperial College London, 2014. http://hdl.handle.net/10044/1/24809.
Streszczenie:
This thesis explores the effects that large-scale land-use/cover change (LUCC) and climate change pose to the terrestrial water cycle, by developing a case study in the Upper Ganges (UG) river basin, in India. In an area experiencing rapid rates of LUCC and changes in irrigation practices, historic land-use maps are developed, based on satellite images, to investigate historical trends of LUCC. Future projection scenarios of LUCC for years up to 2035 are derived from Markov chain analysis. To explore the impacts of those changes in hydrology, the generated maps are used to force the Land Surface Model (LSM) JULES. JULES is found to be reasonably skilful in terms of its ability to reproduce observed streamflow. However, the results indicate that there is much room left for improved estimates of evapotranspiration (ET) fluxes, which JULES is found to over-predict. By dynamically coupling JULES with the crop model InfoCrop, the simulated ET fluxes are improved, compared to the original JULES model. The difference in mean annual ET between the two models (coupled and original) is approximately 150 mm/yr and indicates the potential error in ET flux estimations of an LSM without dynamic vegetation. The impact of LUCC and climate change on the hydrological response of the UG basin is quantified, by calculating variations in hydrological components (streamflow, ET and soil moisture) during the period 2000-2035. Severe increases in the high extremes of flows (+40% in the multi-model mean) are being projected for the nearby future (2030-2035). The changes in all examined hydrological components are greater in the combined land-use and climate change scenario, whilst climate change is the main driver of those changes. These results provide the necessary evidence-base to support regional land-use planning, advanced irrigation practices and develop future-proof water resource management strategies under a water-limited environment.
16
Bring, Arvid. "Arctic Climate and Water Change : Information Relevance for Assessment and Adaptation". Doctoral thesis, Stockholms universitet, Institutionen för naturgeografi och kvartärgeologi (INK), 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-86919.
Streszczenie:
The Arctic is subject to growing economic and political interest. Meanwhile, its water and climate systems are in rapid transformation. Relevant and accessible information about water and climate is therefore vital to detect, understand and adapt to the changes. This thesis investigates hydrological monitoring systems, climate model data, and our understanding of hydro-climatic change, for adaptation to water system changes in the Arctic. Results indicate a lack of harmonized water chemistry data, which may impede efforts to understand transport and origin of key waterborne constituents. Further development of monitoring cannot rely only on a reconciliation of observations and projections on where climate change will be the most severe, as they diverge in this regard. Climate model simulations of drainage basin temperature and precipitation have improved between two recent model generations, but large inaccuracies remain for precipitation projections. Late 20th-century discharge changes in major Arctic rivers generally show excess of water relative to precipitation changes. This indicates a possible contribution of stored water from permafrost or groundwater to sea level rise. The river contribution to the increasing Arctic Ocean freshwater inflow matches that of glaciers, which underlines the importance of considering all sources when assessing change. To provide adequate information for research and policy, Arctic hydrological and hydrochemical monitoring needs to be extended, better integrated and made more accessible. This especially applies to hydrochemistry monitoring, where a more complete set of monitored basins is motivated, including a general extension for the large unmonitored areas close to the Arctic Ocean. Improvements in climate model parameterizations are needed, in particular for precipitation projections. Finally, further water-focused data and modeling efforts are required to resolve the source of excess discharge in Arctic rivers.At the time of doctoral defence the following papers were unpublished and had a status as follows: Paper 2: Accepted; Paper 4: Manuscript
17
SMALL, DAVID LEROY. "A DIAGNOSTIC STUDY OF A POSSIBLE ACCELERATION OF THE HYDROLOGIC CYCLE". University of Cincinnati / OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1159210962.
18
Jung, Gerlinde. "Regional climate change and the impact on hydrology in the Volta Basin of West Africa". Karlsruhe : Forschungszentrum Karlsruhe, 2006. http://d-nb.info/983081263/34.
19
Mileham, Lucinda Juliet. "Impact of climate change on the terrestrial hydrology of a humid, equatorial catchment in Uganda". Thesis, University College London (University of London), 2008. http://discovery.ucl.ac.uk/17227/.
Streszczenie:
Predicted future warming in equatorial Africa, accompanied by greater evaporation and frequent heavy precipitation events, is expected to have substantial but uncertain impacts on terrestrial hydrology. Current low-resolution (~250km) General Circulation Models (GCM) are of limited use to regional and local-scale decision support systems for climate change impacts. Quantitative analyses of the impact of climate change at the local scale requires the improved representation of land-surface characteristics that is afforded by dynamical downscaling of GCM output (HadCM3) using a higher resolution (<50 km) Regional Climate Model (RCM). In this study, precipitation simulated by the RCM, PRECIS (Providing Regional Climates for Impact Studies), is validated at regional (236 000 Km^2) and catchment scales (2 100km^2) and used to quantify the impacts of climate change on runoff and groundwater recharge in the River Mitano catchment of south-western Uganda using a semi-distributed soil moisture balance model (SMBM). PRECIS represents well the spatial and temporal distribution of precipitation but substantially overestimates its magnitude at regional and catchment scales. SMBMs explicitly account for changes in soil moisture and enable assessments of climate change on groundwater by partitioning effective precipitation into groundwater recharge and runoff. The semi-distributed SMBM, calibrated with daily station data a 15-year period (1965-1980), estimates a mean annual recharge of 104 mm•a^{-1} and mean annual surface runoff of 144 mm•a^{-1}. PRECIS predicts a 17% increase in catchment precipitation accompanied by increased precipitation intensity and a 53% increase in potential evapotranspiration by 2070-2100, based on A2 SRS emission scenarios. Under these future conditions, a 62% increase in mean annual recharge to 159 mm•a^{-1} is predicted. This doctoral thesis presents one of the first catchment-scale, hydrological models driven by a RCM in east Africa and one of the first quantitative assessment of the catchment-scale impacts of climate change on groundwater in the humid tropics.
20
Bounhieng, Vilaysane. "INTEGRATED IMPACT ASSESSMENT OF CLIMATE CHANGE ON HYDROLOGY OF THE XEDONE RIVER BASIN, LAO PDR". 京都大学 (Kyoto University), 2016. http://hdl.handle.net/2433/204586.
21
Shang, Linyuan. "Climate Change And Land Use/cover Change Impacts On Watershed Hydrology, Nutrient Dynamics – A Case Study In Missisquoi River Watershed". ScholarWorks @ UVM, 2019. https://scholarworks.uvm.edu/graddis/1016.
Streszczenie:
Watershed regulation of water, carbon and nutrient dynamics support food, drinking water and human development. Projected climate changes and land use/cover change (LUCC) have been identified as drivers of watershed nutrient and hydrological processes and are likely to happen jointly in the future decades. Studying climate change and LUCC impacts on watersheds' streamflow and nutrients dynamics is therefore essential for future watershed management.
This research aimed to unveil how climate change and LUCC affect water and nutrient dynamics in the Missisquoi River watershed, Vermont. We used 12 scenarios of future climate data (2021 – 2050) generated by three GCMs (ccsm4, mri-cgcm3, and gfdl-esm2m) under four Representative Concentration Pathways (RCPs). For LUCC, we used three different scenarios generated by the Interactive Land Use Transition Agent-Based Model (ILUTABM). The three LUCC scenarios were Business As Usual (BAU), Prefer Forest (proForest), and Prefer Agriculture (proAg). New land use maps were generated every 10 years for the period of 2021 – 2050. Combining each climate change and LUCC scenario resulted in 36 scenarios that were used to drive Regional Hydro-Ecologic Simulation System (RHESSys) ecohydrological model.
In chapter 3, we used RHESSys to study streamflow. We found climate was the main driver for streamflow because climate change directly controlled the system water input. For streamflow, climate change scenarios had larger impacts than LUCC, different LUCCs under the same climate change scenario had similar annual flow patterns.
In chapter 4, we used RHESSys to study streamflow NO3-N and NH4-N load. Because fertilizer application is the major source for nitrogen export, LUCC had larger impacts; watersheds with more agricultural land had larger nitrogen loads.
In chapter 5, we developed RHESSys-P by coupling the DayCent phosphorus module with RHESSys to study climate change and LUCC impacts on Dissolved Phosphorus (DP) load. RHESSys-P was calibrated with observed DP data for 2002 – 2004 and validated with data for 2009 - 2010. In both calibration and validation periods, simulated DP basically captured patterns of observed DP. In the validation period, the R2 of simulated vs observed DP was 0.788. Future projection results indicated BAU and proForest annual loads were around 4.0 × 104 kg under all climate change scenarios; proAg annual loads increased from around 4.0 × 104 kg in 2021 to 1.6 × 105 kg in 2050 under all climate change scenarios. The results showed LUCC was the dominant factor for dissolved phosphorus loading.
Overall, our results suggest that, while climate drives streamflow, N and P fluxes are largely driven by land use and management decisions. To balance human development and environmental quality, BAU is a feasible future development strategy.
22
Pryor, John W. "Framework Integrating Climate Model, Hydrology, and Water Footprint to Measure the Impact of Climate Change on Water Scarcity in Lesotho, Africa". Scholar Commons, 2018. https://scholarcommons.usf.edu/etd/7353.
Streszczenie:
Water scarcity is a problem that will be exacerbated by climate change. Being able to model the effect of climate change on water scarcity is important to effectively plan the use of future water resources. This research integrated the Soil and Water Assessment Tool (SWAT), climate model, and water footprint analysis to measure the impact of climate change on future water scarcity. This was achieved through two objectives. The first objective was to create a modeling framework that links the output from climate model to SWAT and combined streamflow outputs from SWAT with water footprint analysis to measure how climate change will impact water scarcity of a river basin. This was accomplished through creating a SWAT model within ArcMap and inputting a topographic, soil, land use, and weather data. Climate Forecast System Reanalysis (CFSR) data were used in lieu of observed weather data due to a lack of available data. SWAT-CUP (Calibration and Uncertainty Program) was used to calibrate two upstream streamflow gauges, then calibrate and validate a third streamflow gauge at the outlet of the Senqu basin in Lesotho. The two upstream streamflow gauges were calibrated from 1986 to 2002. The downstream streamflow gauge was calibrated from 1985 to 2002 and validated from 2003 to 2013. Three Regional Climate Models (RCM), ICHEC-EC-EARTH, MIROC-MIROC5, and CCCma-CanESM2 were downloaded from the Coordinated Regional Downscaling Experiment (CORDEX) dataset. Each RCM was downloaded with two different Coupled Model Intercomparison Project (CMIP5) Representative Concentration Pathways (RCP), RCP 4.5 and RCP 8.5. The RCMs were bias corrected using a cumulative distribution function mapping technique.
These RCMs as well as an average of the RCMs were used as input for the SWAT model to generate future streamflow outputs. The streamflow outputs provide the future blue water availability of the Senqu River. The results showed an overall decrease in streamflow in both RCPs. The second objective was to apply the framework to Lesotho and use the information from the ArcSWAT model and data from the Blue Water Footprint analysis to measure the future potential Blue Water Scarcity of Lesotho. This was accomplished through the Blue Water Footprint of Lesotho generated from the 5th National Blue Footprint analysis. The annual blue water scarcity was calculated as the ratio of the Blue Water Available to Blue Water Footprint. Three approaches were adopted to analyze the water scarcity of Lesotho. The first approach used the national Blue Water Footprint in the water scarcity calculation to investigate the worst-case scenario. The second approach used the modified blue water footprint based on the population living within the Senqu river basin. The third approach used a modified blue water footprint that accounted for the projected population growth of Lesotho. The results of scenario 1 showed there was moderate water scarcity in a period of four years in climate scenario of RCP8.5. The results of scenario 3 showed there were multiple cases of water scarcity in both RCP 4.5 and RCP 8.5 with two years of severe water scarcity. This research is limited by data availability and the results for Lesotho could be improved by accurate dam data and the fine scale water footprint analysis. The modeling framework integrating climate model, hydrology, and water footprint analysis, however, can be applied to other remote places where limited data are available.
23
Hough-Snee, Nathaniel. "Relationships between Riparian Vegetation, Hydrology, Climate and Disturbance across the Western United States". Thesis, Utah State University, 2016. http://pqdtopen.proquest.com/#viewpdf?dispub=10154374.
Streszczenie:
Flow regime, the magnitude, duration and timing of streamflow, controls the development of floodplain landforms on which riparian vegetation communities assemble. Streamflow scours and deposits sediment, structures floodplain soil moisture dynamics, and transports propagules. Flow regime interacts with environmental gradients like climate, land-use, and biomass-removing disturbance to shape riparian plant distributions across landscapes. These gradients select for groups of riparian plant species with traits that allow them to establish, grow, and reproduce on floodplains – riparian vegetation guilds. Here I ask, what governs the distributions of groups of similar riparian plant species across landscapes? To answer this question, I identify relationships between riparian vegetation guilds and communities and environmental gradients across the American West. In Chapter One, I discuss guild-based classification in the context of community ecology and streams. In Chapter Two, I identified five woody riparian vegetation guilds across the interior Columbia and upper Missouri River Basins, USA, based on species’ traits and morphological attributes. I modeled guild occurrence across environmental gradients, including climate, disturbance, channel form attributes that reflect hydrology, and relationships between guilds. I found guilds’ distributions were related to hydrology, disturbance, and competitive or complementary interactions (niche partitioning) between co-occurring guilds. In Chapter Three, I examine floodplain riparian vegetation across the American West, identifying how hydrology, climate, and floodplain alteration shape riparian vegetation communities and their guilds. I identified eight distinct plant communities ranging from high elevation mixed conifer forests to gallery cottonwood forests to Tamarisk-dominated novel shrublands. I aggregated woody species into four guilds based on their traits and morphological attributes: an evergreen tree guild, a mesoriparian shrub guild, a mesoriparian tree guild, and a drought and hydrologic disturbance tolerant shrub guild. Communities and guilds’ distributions were governed by climate directly, and indirectly as mediated through streamflow. In Chapter Four, I discuss the utility of guild-based assessments of riparian vegetation, current limitations to these approaches, and potential future applications of the riparian vegetation guild concept to floodplain conservation and management. The classification of vegetation into functional trait-based guilds provides a flexible, framework from which to understand riparian biogeography, complementing other models frameworks for riparian vegetation.
24
Thakali, Ranjeet. "ANALYZING THE EFFECTS OF CLIMATE CHANGE ON URBAN STORMWATER INFRASTUCTURES". OpenSIUC, 2017. https://opensiuc.lib.siu.edu/theses/2156.
Streszczenie:
The change in the hydrological cycle due to climate change entails more frequent and intense rainfall. As a result, urban water systems will be disproportionately affected by the climate change, especially in such urban areas as Las Vegas, which concentrates its population, infrastructure, and economic activity. Understanding the proper management of urban stormwater in the changing climate is becoming a critical concern to the water resources managers. Proper design and management of stormwater facilities are needed to attenuate the severe effects of extreme rainfall events. In an effort to develop better management techniques and understanding the probable future scenario, this study used the high-resolution climate model data conjunction with advanced statistical methods and computer simulation. Las Vegas Valley which has unique climatic condition and is surrounded by the mountains in every direction was chosen for the study. The North American Regional Climate Change Assessment Program is developing multiple high-resolution projected-climate data from different combinations of regional climate models and global climate models. First, the future design depths was calculated using generalized extreme value method with the aid of L-moment regionalization technique. The projected climate change was incorporated into the model at the 100 year return period with 6h duration depths. Calculation showed that, the projection from different sets of climate model combinations varied substantially. Gridded reanalysis data were used to assess the performance of the climate models. This study used an existing Hydrologic Engineering Center’s Hydrological Modeling System (HEC-HMS) model and Storm Water Management Model (SWMM) developed by the Environmental Protection Agency (EPA) were implemented in the hydrological simulation. Hydrological simulation using HEC-HMS showed exceedances of existing stormwater facilities that were designed under the assumption of stationarity design depth. Low Impact Developments such as permeable pavement and green roof were found to be effective in the attenuation of climate change induced excess surface runoff. The primary purpose of this study is understanding of proper designing, planning and management of the urban stormwater system in the predicted climate scenarios.
25
Yang, Heng. "The hydrologic effects of climate change and urbanization in the Las Vegas Wash Watershed, Nevada". University of Cincinnati / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1384334002.
26
Mukherjee, Rajarshi, i Rajarshi Mukherjee. "Implications of Statistical and Dynamical Downscaling Methods on Streamflow Projections for the Colorado River Basin". Thesis, The University of Arizona, 2016. http://hdl.handle.net/10150/620708.
Streszczenie:
An ensemble of 11 dynamically downscaled CMIP3 GCMs under A2 projection scenario are first bias corrected for the historic (1971-2000) and scenario (2041-2070) period using a Scaled Distribution Mapping (SDM) technique, that preserves the relative change in the monthly mean and variance of precipitation and any model trends in temperature to generate an ensemble of streamflow projections across 3 catchments in the Colorado River basin - Upper Colorado at Lees Ferry, Salt and Verde. The hydroclimatic projections obtained from this method are compared against an existing ensemble of 15 Bias Corrected and Spatially Disaggregated (BCSD) CMIP3 models under A2 projection scenario developed by the Bureau of Reclamation (BOR). The confidence in the DD Ens. stems from its ability to represent historical flow quantiles better than BCSD Ens. Across all three basins, the mean of the dynamically downscaled ensemble (DD Ens.) projects a decrease in both monsoon and winter projected precipitation as compared to mean of the statistically downscaled ensemble (BCSD Ens.). For the Upper Colorado, both Ens. show a shift in peak hydrograph from June to May due to earlier snowmelt, but a projected decrease in precipitation (-5%) by DD Ens. as compared to a slight increase (+2%) by BCSD Ens. results in a lower April snow water equivalent (SWE) and reduced streamflows (14% by DD Ens. as compared to 5% by BCSD Ens.). The streamflow decrease over the Upper Colorado River basin, quantified by both the mean and the spread of the ensemble. is representative in high flows and flows during moist conditions. For smaller basins like Salt and Verde, DD Ens. shows a greater decrease (-11%) in precipitation than BCSD Ens. (-2%), which results in lower peak hydrograph during March and significantly reduced streamflows (-20%&-14% for Salt and Verde by DD Ens. as compared to -3% by BCSD Ens.). This decrease is more substantial in high flows, but occurs across all streamflow quantiles. The future streamflow projection, quantified by the spread of the DD Ens. presents the shifting of the streamflow range downward to be drier in the future.
27
Jung, Gerlinde [Verfasser]. "Regional climate change and the impact on hydrology in the Volta Basin of West Africa / Gerlinde Jung". Karlsruhe : Forschungszentrum Karlsruhe, 2006. http://d-nb.info/983081263/34.
28
Kigobe, Max. "Modelling the effects of land use change and climate variability on the hydrology of the upper Nile". Thesis, Imperial College London, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.555946.
Streszczenie:
The River Nile is the second longest river in the world and its basin covers ten African countries including Uganda. In the light of growing human and industrial demand on its ecosystem, especially water resources, the need to support sustainable basin-wide resource management has risen over the recent past. Most economies in the Nile basin are dependent on rain-fed agriculture, which is strongly affected by climate. Therefore, the basin is vulnerable to a number of issues including land use change, climate change and climate variability. Other stress factors include rapid population growth, land degradation and the prevalence of human disease. These factors are likely to adversely impact on the basin ecosystem and agricultural productivity, which in turn affect the economic development in terms of food security, hydropower generation and provision of ecosystem services. It is imperative to conduct detailed hydrological assessment of the likely impact of land-use changes and climate variability on the hydrology of the Nile basin. This thesis therefore investigates the hydrological response to plausible climate and land use scenarios. This is carried out by testing climate and hydrological modelling tools for the Kyoga basin, within the Upper Nile. Climate modelling involved multi-site spatial and temporal modelling of rainfall in the Kyoga basin using stochastic tools under the Generalised Linear Modelling (GLM) framework. Climate modelling results showed that the structure of the GLM could not represent adequately the variability of rainfall over Kyoga, however, it could represent the variability within designated climatic zones. Assuming independence of the stochastic variability between zones in the Kyoga basin, GLM models for the Kyoga basin were then applied as statistical downs ea ling tools to generate future precipitation sequences conditioned on the results from six general circulation model (GCM) outputs for future climate (2020s, 2050s, 2080s) using results from the Special Report on Emissions Scenarios (SRES) prepared by the Intergovernmental Panel on Climate Change (IPCC) for the Fourth Assessment Report (SRES-AR4). With regard to climate change, warming of the basin resulted in a general increase in precipitation patterns and the results from the use of GLMs suggest that it is likely to have a relatively wetter December - February (DJF), March - May (MAM), September - November (SON) seasons and a much dryer June - August (JJA) season. Hydrological modelling involved the development of a semi-distributed rainfall-runoff model using the Soil Water and Assessment Tool (SWAT), applied on a daily time-scale to investigate the uncertainty associated with precipitation and model parameter identification. The SWAT model was also used to assess the sensitivity of several water resources components to alternative/plausible climate and land use patterns in the Kyoga basin. Hypotheticalland use change scenarios showed that the water resource estimates in the Kyoga basin are sensitive to intensification of agriculture and less sensitive to increase in spatial coverage of grasslands and shrublands. A warmer climate is also associated with increase in potential evapotranspiration, soil water and internal renewable water resources in the Kyoga basin and stream flows at several locations in the basin. The results from this PhD work contribute towards the development of climate and hydrological modelling tools applicable to equatorial climates.
29
Somor, Andrew. "Quantifying streamflow change following bark beetle outbreak in multiple central Colorado catchments". Thesis, The University of Arizona, 2010. http://hdl.handle.net/10150/193435.
Streszczenie:
Over the last decade, millions of acres of western North American forest have been reduced to areas of standing dead trees following eruptions in bark beetle populations. This thesis provides up-to-date information on streamflow response to the recent bark beetle outbreak in subalpine forests of the Colorado Rockies. Streamflow and climate measures are evaluated in eight central Colorado catchments with long-term data records and varying levels of beetle outbreak. No detectable streamflow change is observed in 7 of 8 highly impacted catchments. A significant reduction in streamflow is observed in 1 highly impacted catchment and is likely driven by tree mortality and record warm temperatures. These findings deviate from expected results and have important implications for vegetation and streamflow change under a warmer climate.
30
Stagge, James Howard. "Optimization of Multi-Reservoir Management Rules Subject to Climate and Demand Change in the Potomac River Basin". Diss., Virginia Tech, 2012. http://hdl.handle.net/10919/77144.
Streszczenie:
Water management in the Washington Metropolitan Area (WMA) is challenging because the system relies on flow in the Potomac river, which is largely uncontrolled and augmented by the Jennings-Randolph reservoir, located 9-10 days travel time upstream. Given this lag, release decisions must be made collectively by federal, state and local stakeholders amid significant uncertainty, well in advance of accurate weather forecasts with no ability to recapture excess releases. Adding to this uncertainty are predictions of more severe and sporadic rainfall over the next century, caused by anthropogenic climate change.
This study aims to evaluate the potential impacts of demand and climate change on the WMA water supply system, identifying changes in system vulnerability over the next century and developing adaptation strategies designed to maximize efficiency in a nonstationary system. A daily stochastic streamflow generation model is presented, which succesfully replicates statistics of the historical streamflow record and can produce climate-adjusted daily time-series. Using these time series, a multi-objective evolutionary algorithm is used to optimize the system's operating rules given current and future conditions, considering several competing objectives.Ph. D.
31
Wyatt, Clinton J. W. "Estimating aquifer response following forest restoration and climate change along the Mogollon Rim, northern Arizona". Thesis, Northern Arizona University, 2013. http://pqdtopen.proquest.com/#viewpdf?dispub=1537821.
Streszczenie:
Landscape-scale forest restoration treatments are planned for four national forests in Northern Arizona: the Coconino, Kaibab, Tonto, and Apache-Sitgreaves National Forests. The first analysis area comprises 900,000 acres on the Coconino and Kaibab National Forests where the U.S. Forest Service is proposing restoration activities on approximately 600,000 acres over a ten year period pending acceptance of an Environmental Impact Statement. These forest restoration treatments are intended to accomplish a number of objectives including reducing the threat of catastrophic wild fire and subsequent flooding and to restore forest health, function, and resiliency. Previous studies suggest that in semi-arid, ponderosa pine watersheds there was a possibility to increase surface water yields 15-40% when basal area was reduced by 30-100%. Because of these results, there is considerable interest in the amount of increased water yield that may recharge from these activities.
The objectives of this study were to 1) examine the state of knowledge of forest restoration thinning and its hydrological responses and to evaluate the quality and type of related references that exist within the literature and 2) simulate possible changes in recharge and aquifer response following forest restoration treatments and climate change. A systematic review process following the guidelines suggested by the Collaboration for Environmental Evidence was conducted to examine literature relevant to this topic. The Northern Arizona Regional Groundwater-Flow Model was used to simulate the changes expected from forest restoration treatments and climate change.
The systematic review returned 37 references that were used to answer questions regarding tree removal and the associated hydrological responses. Data from individual studies suggest that forest treatments that reduce tree density tend to increase surface water yield and groundwater recharge while reducing evapotranspiration. On average, there was a 0-50% increase in surface water yield when 5-100% of a watershed was treated. Groundwater results were less conclusive and there was no overall correlation for all studies between percent area treated and groundwater recharge. A majority of studies (33 of 37) reported statistically significant results, either as increases in water yield, decreases in evapotranspiration, or increases in groundwater table elevation. Results are highly variable, and diminish within five to ten years for water yield increases and even quicker (< 4 years) for groundwater table heights.
Using a groundwater-flow model, it was estimated that over the ten-year period of forest restoration treatment there was a 2.8% increase in annual recharge to aquifers in the Verde Valley compared to conditions that existed in 2000-2005. However, these increases were assumed to quickly decline after treatment due to regrowth of vegetation and forest underbrush. Furthermore, estimated increases in groundwater recharge were masked by decreases in water levels, stream baseflow, and groundwater storage resulting from surface water diversions and groundwater pumping. These results should be used in conjunction with other data such as those recovered from paired-watershed studies to help guide decision-making with respect to groundwater supply and demand issues, operations, and balancing the needs of both natural and human communities.
32
Lang, Megan Weiner. "Radar monitoring of hydrology in Maryland's forested coastal plain wetlands implications for predicted climate change and improved mapping /". College Park, Md. : University of Maryland, 2005. http://hdl.handle.net/1903/2944.
Streszczenie:
Thesis (Ph. D.) -- University of Maryland, College Park, 2005.Thesis research directed by: Geography. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
33
Mwangi, Hosea Munge. "Impact of land use change and climate variability on watershed hydrology in the Mara River Basin, East Africa". Thesis, Bangor University, 2016. https://research.bangor.ac.uk/portal/en/theses/impact-of-land-use-change-and-climate-variability-on-watershed-hydrology-in-the-mara-river-basin-east-africa(54692d94-33ee-40a5-9475-d5f1f7148be3).html.
Streszczenie:
Land use change and climate variability are the main drivers of watershed hydrological processes. The main objective of this study was to assess the impact of land use change and climate variability on hydrology of the Mara River Basin in East Africa. Land use maps generated from satellite images were analyzed using the intensity analysis approach to determine the patterns, dynamics and intensity of land use change. Changes in measured streamflow caused separately by land use change and climate variability were separated using the catchment water-energy budget based approach of Budyko framework. The information on past impact of climate variability on streamflow was used to develop a runoff sensitivity equation which was then used to predict the future impact of climate change on streamflow. Finally, the impact of agroforestry on watershed water balance was predicted using SWAT (Soil and Water Assessment Tool) model. Deforestation and expansion of agriculture were found to be dominant and intensive land use changes in the watershed. The deforestation was attributed to illegal encroachment and excision of the forest reserve. The deforested land was mainly converted to small scale agriculture particularly in the headwaters of the watershed. There was intensive conversion of rangeland to largescale mechanized agriculture which accelerated with change of land tenure (privatization). The watershed has a very dynamic land use change as depicted by swap change (simultaneous equal loss and gains of a particular land use/cover) which accounted for more than half of the overall change. This implies that reporting only net change in land use (of MRB) underestimates the total land use change. The results show that streamflow of Nyangores River (a headwater tributary of the Mara River) significantly increased over the last 50 years. Land use change (particularly deforestation) contributed 97.5% of change in streamflow while the rest of the change (2.5%) was caused by climate variability. It was predicted that climate change would cause a moderate 15% increase in streamflow in the next 50 years. SWAT model simulations suggested that implementation of agroforestry in the watershed would reduce surface runoff, mainly due expected improvement of soil infiltration. Baseflow and total water yield would also decrease while evapotranspiration would increase. The changes in baseflow (reduction) and evapotranspiration (increase) were attributed to increased water extraction from the soil and groundwater by trees in agroforestry systems. The impact of agroforestry on water balance (surface runoff, baseflow, water yield and evapotranspiration) was proportional to increase in size of the watershed simulated with agroforestry. Modelling results also suggested that climate variability within the watershed has a profound effect on the change of water balance caused by implementation of agroforestry. It is recommended that authorities should pay more attention to land use change as the main driver of change in watershed hydrology of the basin. More effort should be focused on prevention of further deforestation and agroforestry may be considered as a practical management strategy to reverse/reduce degradation on the deforested parts of the watershed currently under intensive cultivation.
34
Mwangi, Hosea Munge. "Impact of Land Use Change and Climate Variability on Watershed Hydrology in the Mara River Basin, East Africa". Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2017. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-209530.
Streszczenie:
Land use change and climate variability are the main drivers of watershed hydrological processes. The main objective of this study was to assess the impact of land use change and climate variability on hydrology of the Mara River Basin in East Africa. Land use maps generated from satellite images were analyzed using the intensity analysis approach to determine the patterns, dynamics and intensity of land use change. Changes in measured streamflow caused separately by land use change and climate variability were separated using the catchment water-energy budget based approach of Budyko framework. The information on past impact of climate variability on streamflow was used to develop a runoff sensitivity equation which was then used to predict the future impact of climate change on streamflow. Finally, the impact of agroforestry on watershed water balance was predicted using SWAT (Soil and Water Assessment Tool) model. Deforestation and expansion of agriculture were found to be dominant and intensive land use changes in the watershed. The deforestation was attributed to illegal encroachment and excision of the forest reserve. The deforested land was mainly converted to small scale agriculture particularly in the headwaters of the watershed. There was intensive conversion of rangeland to largescale mechanized agriculture which accelerated with change of land tenure (privatization). The watershed has a very dynamic land use change as depicted by swap change (simultaneous equal loss and gains of a particular land use/cover) which accounted for more than half of the overall change. This implies that reporting only net change in land use (of MRB) underestimates the total land use change.
The results show that streamflow of Nyangores River (a headwater tributary of the Mara River) significantly increased over the last 50 years. Land use change (particularly deforestation) contributed 97.5% of change in streamflow while the rest of the change (2.5%) was caused by climate variability. It was predicted that climate change would cause a moderate 15% increase in streamflow in the next 50 years. SWAT model simulations suggested that implementation of agroforestry in the watershed would reduce surface runoff, mainly due expected improvement of soil infiltration. Baseflow and total water yield would also decrease while evapotranspiration would increase. The changes in baseflow (reduction) and evapotranspiration (increase) were attributed to increased water extraction from the soil and groundwater by trees in agroforestry systems. The impact of agroforestry on water balance (surface runoff, baseflow, water yield and evapotranspiration) was proportional to increase in size of the watershed simulated with agroforestry.
Modelling results also suggested that climate variability within the watershed has a profound effect on the change of water balance caused by implementation of agroforestry. It is recommended that authorities should pay more attention to land use change as the main driver of change in watershed hydrology of the basin. More effort should be focused on prevention of further deforestation and agroforestry may be considered as a practical management strategy to reverse/reduce degradation on the deforested parts of the watershed currently under intensive cultivation.
35
Ranatunga, Thushara D. "Simulation of Watersheds Hydrology under Different Hydro-Climatic Settings". University of Cincinnati / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1421925170.
36
Siswanto, Shantosa Yudha. "Impact Evaluation of Future Climate and Land Use Scenarios on Water and Sediment Regime using Distributed Hydrological Modelling in a Tropical Rainforest Catchment in West Java (Indonesia)". Doctoral thesis, Universitat Politècnica de València, 2020. http://hdl.handle.net/10251/153152.
Streszczenie:
[EN] Climate change has occurred in Indonesia, for example, increasing the surface air temperature, including in the Upper Citarum watershed. This phenomenon leads to a lack of water in the dry season, which lowers agriculture production and remains a great obstacle for agricultural activity. Meanwhile, human activity has produced severe LULC changes within the Upper Citarum watershed. This occurs due to the demands of the ever-increasing population growth in the region. As a result, rice field and forested areas have been sacrificed to compensate the urban increment. The general objective of this dissertation is to understand and analyze the impact of climate and LULC changes on the hydrological process and their relationship with historical and future changes by using spatially distributed modeling on the Upper Citarum tropical catchment. The distributed model TETIS has been implemented to obtain the results of past and future scenarios on the water and sediment cycles. Annual historical bathymetries in the reservoir were used to calibrate and validate the sediment sub-model involving Miller's density evolution and trap efficiency of Brune's equation. Climate change has been considered under RCP 45 and RCP 85 trajectories. Meanwhile, to overcome the LULC problem, historical and future LULCs have been studied. LCM model was used to forecast the LULC in 2029. The forecasted results of LCM model show, on one hand, a continuation in the expansion of urban areas at the expense of the contiguous rice fields. The results determined that deforestation and urbanization were the most influential factors for the alteration of the hydrological and sedimentological processes in the Upper Citarum Catchment. Thus, it decreases evapotranspiration, increases water yield by increasing all its components; overland flow, interflow and baseflow. The changes in LULC are currently producing and will produce in the future, a relatively small increment of erosion rates, increasing the area exceeds Tsl erosion. Sediment yield will increase in 2029 as the result of erosion increment. Other LULC scenarios such as conservation, government plan and natural vegetation scenarios are expected to have an increment in total evapotranspiration, the water yield is expected to decrease. Flood regime, erosion and sedimentation are reduced dramatically. Hence, it leads to a massive increment of reservoir and hydropower lifetime signed by a very long period of the lifetime. Climate change alters the magnitude of water balance and can be identified from the shift of infiltration, overland flow, interflow, baseflow and water yield. Those increments finally change the flood regime, catchment erosion. RCP 85 trajectory gives a bigger impact compared to RCP 45 trajectory on hydrological and sediment cycle. . LULC change results a bigger impact on water balance, flood regime, erosion and sedimientation. The combination of climate and LULC change give a bigger impact on the flows of water balance, erosion, flood, sedimentation and will be catastrophic for the hydropower operation of the Saguling Dam.[ES] El cambio climático ha afectado a Indonesia, por ejemplo, incrementando la temperatura del aire en la superficie, incluso en la cuenca del Upper Citarum. Este fenómeno conduce a la falta de agua en la estación seca, reduciendo la producción agrícola lo que es un gran obstáculo para su actividad. Además, la actividad humana ha producido cambios severos en LULC en la cuenca del Upper Citarum, Indonesia. Esto se debe al elevado crecimiento de la población en la región, por el que se han convertido campos de arroz y áreas boscosas en suelo urbano. De esta forma, el objetivo general de esta tesis es comprender y analizar el impacto de los cambios climáticos y LULC en el proceso hidrológico y su relación con los cambios históricos y futuros mediante el uso de modelos distribuidos espacialmente en la cuenca tropical del Upper Citarum. El modelo distribuido TETIS se ha implementado para obtener los resultados de escenarios pasados y futuros en los ciclos de agua y sedimentos. Se usaron batimetrías históricas anuales en el embalse para calibrar y validar el submodelo de sedimentos que involucra la evolución de la densidad de Miller y la eficiencia de retención de la ecuación de Brune. Con el fin de arrojar más luz sobre estos problemas, el escenario de cambio climático se ha implementado en base al modelo de cambio climático bajo las trayectorias RCP 45 y RCP 85. Además, para intentar resolver el problema LULC, también se ha implementado el LULC histórico y futuro. El modelo LCM se usó para pronosticar el LULC en 2029 y los resultados muestran, por un lado, una continuación en la expansión de las áreas urbanas a expensas de los arrozales contiguos. Los resultados determinaron que la deforestación y la urbanización fueron los factores más influyentes para la alteración de los procesos hidrológicos y sedimentológicos en la cuenca del Upper Citarum. Por lo tanto, disminuye la evapotranspiración, aumenta la producción de agua al aumentar todos sus componentes; escorrentía, interflujo y flujo base. Los cambios en LULC están produciendo y producirán, un incremento relativamente pequeño de las tasas de erosión, aumentando el área excede la erosión de Tsl. La producción de sedimentos aumentará en 2029 como resultado del incremento de la erosión. Se espera que otros escenarios de LULC como la conservación, el plan gubernamental y los escenarios de vegetación natural tengan un incremento en la evapotranspiración total, y se espera que la producción de agua disminuya. El régimen de inundación, la erosión y la sedimentación se reducen drásticamente. Por lo tanto, habrá un incremento de la vida útil del embalse y la energía hidroeléctrica. El cambio climático altera la magnitud del equilibrio hídrico y puede identificarse a partir del cambio de infiltración, escorrentía, interflujo, flujo base y producción de agua. Esos incrementos finalmente cambian el régimen de inundación y erosión de la cuenca. La trayectoria RCP 85 tiene un mayor impacto en comparación con la trayectoria RCP 45 en el ciclo hidrológico y de sedimentos. El cambio de LULC tiene un mayor impacto en el balance hídrico, el régimen de inundación, la erosión y la sedimentación. La combinación del cambio climático y LULC tiene un mayor impacto en los flujos de equilibrio hídrico, erosión, inundación, sedimentación y será catastrófico para la operación hidroeléctrica de la presa Saguling.
[CA] El canvi climàtic ha afectat Indonèsia, per exemple, incrementant la temperatura de l'aire en la superfície, inclús en la conca de l'Upper Citarum. Aquest fenomen conduïx a la falta d'aigua en l'estació seca, reduint la producció agrícola, el que és un gran obstacle per a la seua activitat. A més, l'activitat humana ha produït canvis severs en LULC en la conca de l'Upper Citarum, Indonèsia. Açò es deu a l'elevat creixement de la població en la regió, motiu pel qual s'han anat convertint camps d'arròs i àrees boscoses en sòl urbà. D'aquesta manera, l'objectiu general d'aquesta tesi és comprendre i analitzar l'impacte dels canvis climàtics i LULC en el procés hidrològic i la seua relació amb els canvis històrics i futurs per mitjà de l'ús de models distribuïts espacialment en la conca tropical de l'Upper Citarum. El model distribuït TETIS s'ha implementat per a obtindre els resultats d'escenaris passats i futurs en els cicles de l'aigua i sediments. Es van usar batimetries històriques anuals en l'embassament per a calibrar i validar el submodel de sediments que involucra l'evolució de la densitat de Miller i l'eficiència de retenció de l'equació de Brune. Amb la finalitat de donar més llum a aquests problemes, l'escenari de canvi climàtic s'ha implementat basant-se en el model de canvi climàtic davall les trajectòries RCP 45 i RCP 85. A més, per a intentar resoldre el problema LULC, també s'ha implementat el LULC històric i futur. El model LCM es va usar per a pronosticar el LULC en 2029 i els resultats mostren, d'una banda, una continuació en l'expansió de les àrees urbanes a costa dels arrossars contigus. Els resultats van determinar que la desforestació i la urbanització van ser els factors més influents per a l'alteració dels processos hidrològics i sedimentològics en la conca de l'Upper Citarum. Per tant, disminuïx l'evapotranspiració, augmenta la producció d'aigua en augmentar tots els seus components; escorrentia, interflux i flux base. Els canvis en LULC estan produint i produiran, un increment relativament xicotet de les taxes d'erosió, augmentant l'àrea excedix l'erosió de Tsl. La producció de sediments augmentarà en 2029 com a resultat de l'increment de l'erosió. S'espera que altres escenaris de LULC com la conservació, el pla governamental i els escenaris de vegetació natural tinguen un increment en l'evapotranspiració total, i s'espera que la producció d'aigua disminuïsca. El règim d'inundació, l'erosió i la sedimentació es reduïxen dràsticament. Per tant, hi haurà un increment de la vida útil de l'embassament i l'energia hidroelèctrica. El canvi climàtic altera la magnitud de l'equilibri hídric i pot identificar-se a partir del canvi d'infiltració, escorrentia, interflux, flux base i producció d'aigua. Eixos increments finalment canvien el règim d'inundació i erosió de la conca. La trajectòria RCP 85 té un major impacte en comparació amb la trajectòria RCP 45 en el cicle hidrològic i de sediments. El canvi de LULC té un major impacte en el balanç hídric, el règim d'inundació, l'erosió i la sedimentació. La combinació del canvi climàtic i LULC té un major impacte en els fluxos d'equilibri hídric, erosió, inundació, sedimentació i serà catastròfic per a l'operació hidroelèctrica de la presa Saguling.
thank the Directorate General of Higher Education of Indonesia (DIKTI), for granting me the opportunity to pursue PhD study and adventure in Europe. The authors are also thankful to the Spanish Ministry of Economy and Competitiveness through the research projects TETISMED (CGL2014-58127-C3-3-R) and TETISCHANGE (RTI2018-093717-B-I00).
Siswanto, SY. (2020). Impact Evaluation of Future Climate and Land Use Scenarios on Water and Sediment Regime using Distributed Hydrological Modelling in a Tropical Rainforest Catchment in West Java (Indonesia) [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/153152
TESIS
37
Witte, Becky A. "Impacts of Climate Change and Population Growth on Water Stress in the Tucson Active Management Area". Thesis, The University of Arizona, 2013. http://hdl.handle.net/10150/293624.
Streszczenie:
This study assesses the effects of a changing climate and population growth on water resources by modeling groundwater supplies in the Tucson Active Management Area. The finite-difference flow model, Modflow, is used to incorporate agricultural, municipal, and industrial well pumping along with natural and artificial recharge. This study expands on a Modflow model created by the Arizona Department of Water Resources to determine the impacts from limited water supplies and increased demand (Mason and Bota, 2006). Groundwater conditions and pumping in the Upper Santa Cruz and Avra Valley sub-basins are modeled starting in the year 1940 and continue to 2009. The model predicts pumping and recharge for the period of 2010 to 2050. During this projection period, nine scenarios based on various climate and population conditions are evaluated. Climate impacts are reflected in the amount of recharge entering the groundwater system. Local and regional climate conditions are incorporated since a large portion of the Tucson water supply is provided by the Colorado River water delivered along the Central Arizona Project (CAP). A decrease of 10% to the mean natural flow in the Colorado River over the next 50 years is used to predict Colorado River flows and shortages. Additionally, a 20% streamflow reduction case and two scenarios that evaluate the local and regional shortages individually are presented. Operational rules for the deliveries of the CAP water during shortage conditions are utilized to represent the system. The percentage of population growth is varied around the current case, which is extrapolated from data provided by the Arizona Department of Water Resources. Water demand is based upon the initial population, annual population growth, and gallons per capita day, which is a measurement of water use per person. The three population scenarios are limited growth, current case, and high growth. Results indicate groundwater depletion conditions are the worst during the high growth/shortage scenarios and best for the limited growth scenario. The change in storage of the aquifer is greatly driven by the pumping, which is dependent on population. For the shortage condition, the decline in natural recharge has a much larger effect on the change in water storage compared to the artificial recharge reductions due to shortages of CAP water.
38
Liu, Huidong. "Environmental change in former and present Karner Blue butterfly habitats". Bowling Green State University / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1210181611.
39
Cresso, Matilda. "The Impact of Climate Changes On Hydrology and Water Resources In the Andean Páramos-Colombia". Thesis, Stockholms universitet, Institutionen för naturgeografi, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-179849.
Streszczenie:
Páramo ecosystems are unique alpine grasslands found at high altitudes (2000-5000 m a.s.l.) in the Andean mountain range. While they provide a wide range of important ecosystem services, such as organic carbon sinks, protect endemic species, provide agriculture services, act as recreation sites etc., their perhaps most important service is found in their ability to regulate water flows. The unique volcanic soil properties and endemic plant life that resides in these areas have an exceptional ability to capture, regulate and store water. Colombia has the world’s largest stretch of páramo areas, which supply almost the entire country with clean tap water without active filtration initiatives. Currently there are around seven million people living in Bogotá, the main capital. Northeast of the capital, in the Eastern Range of the Colombian Andes, the Chingaza National Park (CNP) is located. In this park, there are approximately 645 km² of páramo ecosystems, which supplies around 80 % of all the tap water used in Bogotá. However, with an expanding population growth and urbanisation, the demand for water is increasing rapidly. The long-lasting conflict within the country has prevented the exploitation of the economical goods belonging to the páramo ecosystems. Recent peace agreements have opened up for international trade, tourism and an expanding industry. However, the lack of regulations, which protect the páramo ecosystems, have now resulted in an increasing pressure of these systems. As such, sustainable adaptation plans are required across multiple stakeholder levels in order to prevent further deterioration of the páramos. Moreover, the anthropogenic climate changes are posing a threat to these fragile environments. An increasing temperature and changing rainfall patterns are expected to affect the hydroclimatic conditions, especially on high altitudes where these ecosystems are located. Nevertheless, the internal and external processes governing these ecosystems are highly complex and the knowledge gaps are many. One reason for this is that the remote and inaccessible locations results in generally scarcely distributed networks of monitoring stations. In this study, CNP was chosen due to the relatively well-monitored network of stations. Long-term temperature, precipitation and runoff data was analysed to identify the hydroclimatic conditions in the park. Regional downscaled precipitation, minimum and maximum temperature simulations under the Representative Concentration Pathways (RCP) 4.5 and 8.5, covering the period 2041-2065 were obtained from the WorldClim 1.4 database. Interpolated historical observations for the same parameters but during the period 1960-1990, covering CNP, were derived from the same database. These interpolated historical parameters were used for establishing upper and lower precipitation and temperature boundaries for where a páramo ecosystem can thrive during future RCP-scenarios. Historically, the hydroclimatic conditions in CNP has been characterised by a high input of water from precipitation, low evapotranspiration due to low temperatures and clouds presence, and a stable and abundant runoff. However, the results from this study suggest increasing temperature and precipitation boundaries during both RCP 4.5 and RCP 8.5 compared to historical interpolated data. Furthermore, there is a tendency towards prolonged and amplified seasons, with wetter wet season and drier dry seasons. When mapping suitable páramo environments under future RCP-scenarios, there is a tendency towards decreasing suitable páramo areas, especially during dry season. However, the findings in this report are merely based on temperature and precipitation parameters. Other forcing factors (ENSO, cloud cover, fog, occult precipitation, land use etc.) that also influence these environments and the ability to adapt to new hydroclimatic conditions, were not investigated. In order to prevent further loss of these environments and their associated ecosystem services, it is recommended to apply modern techniques, such as remote sensing in combination with traditional fieldwork, point samples and hydrological models in future studies.
40
MAXIMOV, IVAN A. "INTEGRATED ASSESSMENT OF CLIMATE AND LAND USE CHANGE EFFECTS ON HYDROLOGY AND WATER QUALITY OF THE UPPER AND LOWER GREAT MIAMI RIVER". University of Cincinnati / OhioLINK, 2003. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1060964940.
41
Bhandari, Ranjit. "ANALYZING STREAMFLOW VARIABILITY UNDER CMIP5 PROJECTIONS USING SWAT MODEL". OpenSIUC, 2018. https://opensiuc.lib.siu.edu/theses/2363.
Streszczenie:
For analyzing the effect of climate change on the streamflow at a regional scale, six General Circulation Models (GCMs) were selected from among eighteen GCMs from the Coupled Model Intercomparison Project (CMIP5) for the Pajaro River Watershed in central California. The 1/8° latitude-longitude resolution bias-corrected and downscaled CMIP5 projections were utilized for an ensemble of GCMs under four Representative Concentration Pathways (RCP2.6, RCP4.5, RCP6.0 and RCP8.5). The twenty-first century is segregated into three time-periods (2016-2039, 2040-2069 and 2070-2099) for comparing the streamflow against changing precipitation and temperature according to the CMIP5 projections. The daily maximum and daily minimum temperature are projected to consistently rise through to the latter part of the century. Csiro-mk3-6 and canesm2 models project an increase of 3.1°C in annual average daily maximum temperature and 3.4°C in annual average daily minimum temperature respectively in 2070-2099 period under RCP8.5 scenarios. Future precipitation is projected to increase in January and February, which means the wet months in the Pajaro River Watershed are likely to get more rainfall. The dry months would continue to receive diminished precipitation throughout the century. The streamflow was increasing on future January, and sporadically, in February months but diminished during the dry months. The range of annual average streamflow for the future years stretched from 0.1 to 29.1 m3/s for the GCM ensemble, mostly close to the lower limit. The results suggest considering multiple climate change scenarios and evaluating alternative setups would provide a robust basis for hydrological assessment.
42
Maldonado, Philip Pasqual. "Low Flow Variations in Source Water Supply for the Occoquan Reservoir System Based on a 100-Year Climate Forecast". Thesis, Virginia Tech, 2011. http://hdl.handle.net/10919/35203.
Streszczenie:
The reliability of future water supplies comes into question with the onset of global climate change and the variations in local weather patterns that it brings. Changes in temperature, precipitation, soil moisture, and sea level can all have an impact on drinking water storage and supply. As these impacts are realized, it is increasingly important to use forward projecting estimates of future supply through the use of general circulation models (GCMs). GCMs can be used to predict changes in local weather over the next century. Using GCM data as input to a hydrologic model of local water supplies, water supply managers can assess and be better prepared for the impact of these possible changes.
Land use/demand in particular has an impact on runoff characteristics within a watershed. By incorporating changes in land use/demand into hydrologic model simulations, a more complete picture can be generated of the possible runoff characteristics, and thereby source water supply. The four land use scenarios used in this study are: 1) present day land use/demand; 2) projected land use/demand to 2040; 3) projected land use/demand to 2070; and 4) projected land use/demand to 2100.
This study uses established techniques to incorporate both climate and land use/demand change into a hydrologic model of the Occoquan watershed, which encompasses an area of approximately 1,550 square kilometers in Northern Virginia, U.S.A., and is part of the drinking water supply to approximately 1.7 million residents.
Master of Science
43
Niraula, Rewati. "Understanding the Hydrological Response of Changed Environmental Boundary Conditions in Semi-Arid Regions: Role of Model Choice and Model Calibration". Diss., The University of Arizona, 2015. http://hdl.handle.net/10150/594961.
Streszczenie:
Arid and semi-arid basins in the Western United States (US) have been significantly impacted by human alterations to the water cycle and are among the most susceptible to water stress from urbanization and climate change. The climate of the Western US is projected to change in response to rising greenhouse gas concentrations. Combined with land use/land cover (LULC) change, it can influence both surface and groundwater resources, both of which are a significant source of water in the US. Responding to this challenge requires an improved understanding of how we are vulnerable and the development of strategies for managing future risk. In this dissertation, I explored how hydrology of semi-arid regions responds to LULC and climate change and how hydrologic projections are influenced by the choice and calibration of models. The three main questions I addressed with this dissertation are: 1. Is it important to calibrate models for forecasting absolute/relative changes in streamflow from LULC and climate changes? 2. Do LSMs make reasonable estimates of groundwater recharge in the western US? 3. How might recharge change under projected climate change in the western US? Results from this study suggested that it is important to calibrate the model spatially to analyze the effect of LULC change but not as important for analyzing the relative change in streamflow due to climate change. Our results also highlighted that LSMs have the potential to capture the spatial and temporal patterns as well as seasonality of recharge at large scales. Therefore, LSMs (specifically VIC and Noah) can be used as a tool for estimating current and future recharge in data limited regions. Average annual recharge is projected to increase in about 62% of the region and decrease in about 38% of the western US in future and varies significantly based on location (-50% - +94 for near future and -90% to >100% for far future). Recharge is expected to decrease significantly (-13%) in the South region in the far future. The Northern Rockies region is expected to get more recharge in both in the near (+5.1%) and far (+9.0%) future. Overall, this study suggested that land use/land cover (LULC) change and climate change significantly impacts hydrology in semi-arid regions. Model choice and model calibrations also influence the hydrological predictions. Hydrological projections from models have associated uncertainty, but still provide valuable information for water managers with long term water management planning.
44
Siebenmorgen, Christopher B. "Potential climate change impacts on hydrologic regimes in northeast Kansas". Thesis, Kansas State University, 2010. http://hdl.handle.net/2097/6993.
Streszczenie:
Master of ScienceDepartment of Biological & Agricultural Engineering
Kyle R. Douglas-Mankin
The Great Plains once encompassed 160 million hectares of grassland in the central United States. In the last several decades, conversion of grassland to urban and agricultural production areas has caused significant increases in runoff and erosion. Past attempts to slow this hydrologic system degradation have shown success, but climate change could once again significantly alter the hydrology. The Intergovernmental Panel on Climate Change (IPCC) studies the state of knowledge pertaining to climate change. The IPCC has developed four possible future scenarios (A1, A2, B1 and B2). The output temperature and precipitation data for Northeast Kansas from fifteen A2 General Circulation Models (GCMs) were analyzed in this study. This analysis showed that future temperature increases are consistent among the GCMs. On the other hand, precipitation projections varied greatly among GCMs both on annual and monthly scales. It is clear that the results of a hydrologic study will vary depending on which GCM is used to generate future climate data. To overcome this difficulty, a way to take all GCMs into account in a hydrologic analysis is needed. Separate methods were used to develop three groups of scenarios from the output of fifteen A2 GCMs. Using a stochastic weather generator, WINDS, monthly adjustments for future temperature and precipitation were applied to actual statistics from the 1961 – 1990 to generate 105 years of data for each climate scenario. The SWAT model was used to simulate watershed processes for each scenario. The streamflow output was analyzed with the Indicators of Hydrologic Alteration program, which calculated multiple hydrologic indices that were then compared back to a baseline scenario. This analysis showed that large changes in projected annual precipitation caused significant hydrologic alteration. Similar alterations were obtained using scenarios with minimal annual precipitation change. This was accomplished with seasonal shifts in precipitation, or by significantly increasing annual temperature. One scenario showing an increase in spring precipitation accompanied by a decrease in summer precipitation caused an increase in both flood and drought events for the study area. The results of this study show that climate change has the potential to alter hydrologic regimes in Northeast Kansas.
45
Zhang, Feng. "Climate change assessment for the southeastern United States". Diss., Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/45770.
Streszczenie:
Water resource planning and management practices in the southeastern United States may be vulnerable to climate change. This vulnerability has not been quantified, and decision makers, although generally concerned, are unable to appreciate the extent of the possible impact of climate change nor formulate and adopt mitigating management strategies. Thus, this dissertation aims to fulfill this need by generating decision worthy data and information using an integrated climate change assessment framework.
To begin this work, we develop a new joint variable spatial downscaling technique for statistically downscaling gridded climatic variables to generate high-resolution, gridded datasets for regional watershed modeling and assessment. The approach differs from previous statistical downscaling methods in that multiple climatic variables are downscaled simultaneously and consistently to produce realistic climate projections. In the bias correction step, JVSD uses a differencing process to create stationary joint cumulative frequency statistics of the variables being downscaled. The functional relationship between these statistics and those of the historical observation period is subsequently used to remove GCM bias. The original variables are recovered through summation of bias corrected differenced sequences. In the spatial disaggregation step, JVSD uses a historical analogue approach, with historical analogues identified simultaneously for all atmospheric fields and over all areas of the basin under study.
In the second component of the integrated assessment framework, we develop a data-driven, downward hydrological watershed model for transforming the climate variables obtained from the downscaling procedures to hydrological variables. The watershed model includes several water balance elements with nonlinear storage-release functions. The release functions and parameters are data driven and estimated using a recursive identification methodology suitable for multiple, inter-linked modeling components. The model evolves from larger spatial/temporal scales down to smaller spatial/temporal scales with increasing model structure complexity. For ungauged or poorly-gauged watersheds, we developed and applied regionalization hydrologic models based on stepwise regressions to relate the parameters of the hydrological models to observed watershed responses at specific scales.
Finally, we present the climate change assessment results for six river basins in the southeastern United States. The historical (baseline) assessment is based on climatic data for the period 1901 through 2009. The future assessment consists of running the assessment models under all IPCC A1B and A2 climate scenarios for the period from 2000 through 2099. The climate assessment includes temperature, precipitation, and potential evapotranspiration; the hydrology assessment includes primary hydrologic variables (i.e., soil moisture, evapotranspiration, and runoff) for each watershed.
46
Swetnam, Tyson L., Paul D. Brooks, Holly R. Barnard, Adrian A. Harpold i Erika L. Gallo. "Topographically driven differences in energy and water constrain climatic control on forest carbon sequestration". WILEY, 2017. http://hdl.handle.net/10150/624369.
Streszczenie:
Mountains are vital to ecosystems and human society given their influence on global carbon and water cycles. Yet the extent to which topography regulates montane forest carbon uptake and storage remains poorly understood. To address this knowledge gap, we compared forest aboveground carbon loading to topographic metrics describing energy balance and water availability across three headwater catchments of the Boulder Creek Watershed, Colorado, USA. The catchments range from 1800 to 3500 m above mean sea level with 46-102 cm/yr mean annual precipitation and -1.2 degrees to 12.3 degrees C mean annual temperature. In all three catchments, we found mean forest carbon loading consistently increased from ridges (27 +/- 19 Mg C ha) to valley bottoms (60 +/- 28 Mg C ha). Low topographic positions held up to 185 +/- 76 Mg C ha, more than twice the peak value of upper positions. Toe slopes fostered disproportionately high net carbon uptake relative to other topographic positions. Carbon storage was on average 20-40 Mg C ha greater on north to northeast aspects than on south to southwest aspects, a pattern most pronounced in the highest elevation, coldest and wettest catchment. Both the peak and mean aboveground carbon storage of the three catchments, crossing an 11 degrees C range in temperature and doubling of local precipitation, defied the expectation of an optimal elevation-gradient climatic zone for net primary production. These results have important implications for models of forest sensitivity to climate change, as well as to predicted estimates of continental carbon reservoirs.
47
Braff, Pamela. "Evaluating The Impacts Of Land Use And Climate Change On The Hydrology Of Headwater Wetlands In The Coastal Plain Of Virginia". W&M ScholarWorks, 2020. https://scholarworks.wm.edu/etd/1593091561.
Streszczenie:
Located at the interface between uplands and surface water networks, headwater wetlands act as a natural filter to improve downstream water quality and play a critical role in maintaining the ecological integrity of downstream aquatic ecosystems. Vulnerable to development pressure, as well as indirect impacts from land use and climate change, the loss and alteration of headwater wetlands has been linked to the loss of biodiversity and regional water quality declines worldwide. The overall goal of this dissertation is to address some of the challenges associated with the management and conservation of headwater wetlands in the coastal plain of Virginia including: the identification of palustrine forested wetlands in flat coastal landscapes (Chapter II); and improved understanding of the impacts of land use (Chapter III) and climate change (Chapter IV) on the hydrologic regime of headwater wetlands. First, a simple model of wetland distribution was developed by characterizing the depth to groundwater using widely available geospatial data, including surface water features and a high-resolution digital elevation model. Comparison with the National Wetland Inventory (NWI) and targeted field validation indicated that this model provides an effective approach to identify palustrine forested wetlands often unmapped by NWI. Results from this study indicate that there may be at least 37% more wetland area than is currently mapped within the study area; and that in the future, modeling approaches should be used in addition to NWI mapping to better understand the full extent and distribution of wetlands in forested areas. The impacts of land use and climate change were then investigated through field studies of headwater wetland hydrology and community composition. Potential differences in headwater wetland hydrology were evaluated through an index of hydrophytic vegetation occurrence, the wetland prevalence index (PI). Changes in PI between sapling and canopy strata, with respect to local land use, indicated that decreased forest cover was associated with a shift in plant community composition, and that increasing road density was associated with a shift towards more upland type species, while increasing agricultural cover was associated with a shift towards more wetland type species. The effects of climate change, including rising temperatures and altered precipitation patterns were evaluated by developing an empirical model of water table depth for coastal headwater wetlands. Wetland water levels were simulated under current and potential future conditions to evaluate the impact of climate change on the hydrologic regime of headwater wetlands. Based on the model scenarios applied in this study, it appears that decreasing water availability may lead to drier conditions at headwater wetlands by the end of the 21st century, with a substantial decline in minimum water levels and a 3-10% decline in average annual percent saturation. Collectively, the results of this dissertation provide practical insights for improving the conservation and management of coastal headwater wetlands. Improved understanding of the extent and distribution of previously unmapped forested wetlands can improve the capacity to monitor wetland loss and degradation. Additionally, clarifying the influence of land use and climate on the hydrologic regime of these wetlands, can help improve the capacity to forecast and then mitigate potential future impacts to wetland hydrology.
48
Henriques, Catarina. "Hydrology and water resources management in East Anglia and north west England in the context of climate and socio-economic change". Thesis, Cranfield University, 2007. http://dspace.lib.cranfield.ac.uk/handle/1826/2743.
Streszczenie:
Future water resource management is of primary importance to society, economy and the environment. Planning for climate change and adapting to those changes, which requires an understanding of the complex consequences of climate change for the hydrology and human and environmental uses of water, is important for a sustainable future. This research study holistically explored possible implications of global climate change and regional socioeconomic change on water resource management in the contrasting regions of East Anglia and North West England. A model was developed to estimate the impacts on the catchment hydrology and on the robustness of the regional water resources system as a consequence of future changes. For a range of plausible futures, the hydrological responses are mainly affected by changes in climate, whereas the impacts on water resources are primarily determined by socio-economic factors that can exacerbate or ameliorate the impacts of climate. Under economically-focused futures, water demand increases at the expense of the environment’s allocation of water, and the water quality is deteriorated, which compromises current environmental legislative requirements. Under environmentally-focused futures the environment is protected but at the expense of society and the economy. East Anglia is generally more vulnerable than North West England because water supply is scarcer, river flows are lower and it has a much larger arable agricultural area; e.g. under most futures there is a deficit between the water supply and demand. Anticipatory adaptation options within the context of the storylines of each socio-economic scenario were generally successful in managing water demand and supply and avoiding conflicts between the water users. This study illustrates the importance of regional integrated assessments which allow for future socio-economic changes in evaluating the impacts of climate change on the hydrology, water environment and water resources.
49
La, Frenierre Jeff David. "Assessing the Hydrologic Implications of Glacier Recession and the Potential for Water Resources Vulnerability at Volcan Chimborazo, Ecuador". The Ohio State University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=osu1402593347.
50
Datko, James A. "Carbon mitigation in the power sector as a solution to global climate change, a good idea but how much water will it cost?" The Ohio State University, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=osu1284138162.