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1
Tilleard, John. "River channel adjustment to hydrologic change /." Connect to thesis, 2001. http://eprints.unimelb.edu.au/archive/00000241.
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MacGregor, Angus James. "A palaeoecological reconstruction of the Lower Snowy River, East Gippsland, Victoria : environmental response to climate change, land use, and river regulation /." Title page, contents and abstract only, 2001. http://web4.library.adelaide.edu.au/theses/09AEVH/09aevhm147.pdf.
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Rose, Teresa, and n/a. "AN INTERDISCIPLINARY STUDY INTO THE IMPACTS OF FLOW REGULATION ON AN UPLAND GRAVEL BED RIVERINE ENVIRONMENT: A TRIBUTARY CONFLUENCE IN THE SNOWY RIVER DOWNSTREAM OF JINDABYNE DAM, AUSTRALIA." University of Canberra. Cooperative Research Centre for Freshwater Ecology, 1999. http://erl.canberra.edu.au./public/adt-AUC20080917.153237.
Full textAbstract:
Inter-Basin-Water Transfers significantly reduce flow and sediment regimes to the
downstream ecosystem effecting differential channel adjustment at various locations. It
is not known how macroinvertebrates adjust to flow regulation, either spatially or
temporally, because research is lacking into how morphological adjustment affects
benthic habitat. Feedback mechanisms that initiate the adjustment process must first be
identified, then the effect on benthic habitat becomes apparent, thus, providing a link to
macroinvertebrate response.
Since regulation there has been a 95% reduction in flow volume, a complete downward
shift in both the flow duration and flood frequency curves and a 194% increase in flow
constancy compared to the pre- dam period. Furthermore, Jindabyne Dam traps 99.9%
of the total incoming sediment load.
Upstream of the tributary the dominant river response was accommodation adjustment
with subsequent contraction of the river channel. Associated feedback mechanisms
were ?armouring? and vegetation encroachment. Downstream of the tributary response
was more complex, with channel contraction through aggradation and specifically the
formation of a tributary mouth bar and fan, mid channel lobate bar, transverse bar and
in-channel bench. Associated feedback mechanisms were interactions between
vegetation and sediment; channel morphology, flow and sediment distribution; and
sediment distribution, flow and channel morphology. These processes have had site
specific and reach scale impacts on benthic habitat.
Macroinvertebrate response to flow regulation was habitat specific (riffle or edge) and
seemed to correspond to either site, or reach scale morphological adjustment, whereas,
flow constancy seemed to affect edge macroinvertebrates throughout both reaches.
Spatially, macroinvertebrates have not adjusted to the post- dam flow regime and
temporally, macroinvertebrates have not recovered 30 years after the closure of
Jindabyne Dam. How physical processes change habitats and how these impact on a
river?s ecology and at what scale, are important considerations in river management.
4
Bradbeer, David Ross. "Lesser Snow Geese and agricultural habitat use on the Fraser River delta." Thesis, University of British Columbia, 2007. http://hdl.handle.net/2429/31864.
Full textAbstract:
Lesser Snow Geese winter on the Fraser River delta of south-western British Columbia
and feed on upland agricultural crops. With the recent loss of foreshore marsh habitat adjacent
to the Vancouver International Airport, agricultural habitats have become more important. The
loss of foreshore habitat, combined with a growing Snow Goose population, will increase the
grazing pressure the birds exert on farm fields in West Delta. Because Snow Geese can overgraze
perennial forage grasses, conflicts with farmers will likely escalate. Providing foraging
opportunities for Snow Geese while minimizing the conflict between the geese and Delta
farmers should be the goal of management efforts. To accomplish these goals, the Alaksen
National Wildlife Area (ANWA) and Greenfields cover crop program must be managed in a
way that attracts Snow Geese to these areas.
From 1995 to 2000 Snow Geese used the Alaksen National Wildlife Area during both
the fall and late winter hunting seasons. Fewer geese fed outside the Alaksen National Wildlife
Area during open hunting seasons compared to when the seasons were closed. Snow Geese
used perennial forage, cover crops, potato, and grain between 1995 and 2000. Between October
2005 and April 2006,1 documented patterns of agricultural field use on Westham Island and
Brunswick Point and assessed how crop type, hunting, and field size influenced those patterns. I
used foraging theory as a framework to assess how temporal changes in the quality and quantity
of food influenced crop use. The main determinant of field use was crop type. Nutrient content
appeared to be important to the order of crop use. Snow Geese used the crops that contained the
highest concentrations of crude protein (cover crops) and simple carbohydrates (potatoes and
barley grain) first in the fall and early winter. Perennial forage crops contained the highest
concentration of indigestible crude fibre and were not used until the higher quality crops were depleted. Absolute crop biomass did not seem to influence crop use patterns because Snow
Geese initially ignored perennial forage fields that contained more biomass than cover crop and
potato fields. In March and April Snow Geese continued to use perennial forage fields, but also
grain stubble and cover crop fields. Use of these fields may have been related to the presence of
newly sprouting forbs and grasses. Snow Geese moved outside of the Alaksen National
Wildlife Area despite an open hunting season in November 2005. Food depletion within the
Alaksen National Wildlife Area may force Snow Geese to tolerate hunting pressure and was
likely a factor that caused the geese to use fields outside the area.Land and Food Systems, Faculty of
Graduate
5
Larson, Robert, and 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.
Full textAbstract:
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. --
6
Böckelmann, Uta. "Description and characterization of bacteria attached to lotic organic aggregates (river snow) in the Elbe River of Germany and the South Saskatchewan River of Canada." [S.l.] : [s.n.], 2001. http://deposit.ddb.de/cgi-bin/dokserv?idn=96442097X.
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Dery, Stephen J. "The role of blowing snow in the hydrometeorology of the Mackenzie River Basin /." Thesis, McGill University, 2001. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=36909.
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Despite being ubiquitous in the Mackenzie River Basin (MRB) of Canada, the role of snow in its energy and water budgets are still open to much speculation. This thesis presents a multi-scale analysis of the contribution of blowing snow to the hydrometeorology of the MRB. A climatology of adverse wintertime weather events is first presented and demonstrates that blowing snow events are rare within the forested sections of the MRB but become more frequent in the northern parts of the basin covered by Arctic tundra. It is these areas which experience the largest impacts of blowing snow transport and sublimation due to large-scale processes. To further assess the mesoscale and microscale effects of blowing snow to the northern regions of the MRB, the development of a bulk blowing snow model is then described. The single- and double-moment versions of the PIEKTUK blowing snow model are shown to produce equivalent results as a previous spectral version of the numerical model while operating about 100 times faster. The application of the double-moment PIEKTUK model (PIEKTUK-D) to a Canadian Arctic tundra site near the northern tip of the MRB reveals that blowing snow sublimation depletes ≈3 mm snow water equivalent (swe) from the snowpack over a period of 210 days during the winter of 1996/1997 at Trail Valley Creek, Northwest Territories. Various assumptions on the state of the background thermodynamic profiles and their evolution during blowing snow, however, can yield significantly higher (>300%) rates of sublimation over the same period. PIEKTUK-D is then coupled to the Mesoscale Compressible Community (MC2) model for an interactive simulation of a ground blizzard at Trail Valley Creek. This coupled mesoscale simulation reveals that moistening and cooling of near-surface air associated with blowing snow sublimation is observed but mitigated in part by advective and entrainment processes. Combined, blowing snow sublimation and mass divergence are then shown to rem
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MacDonald, Matthew Kenneth. "Hydrometeorological response to chinook winds in the South Saskatchewan River Basin." Thesis, University of Edinburgh, 2016. http://hdl.handle.net/1842/19561.
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The South Saskatchewan River Basin (SSRB) is amongst the largest watersheds in Canada. It is an ecologically diverse region, containing Montane Cordillera, Boreal Plains and Prairie ecozones. The SSRB is subject to chinooks, which bring strong winds, high temperatures and humidity deficits that alter the storage of water during winter. Approximately 40% of winter days experience chinooks. Ablation during chinooks has not been quantified; it is not known how much water evaporates, infiltrates or runs off. The aim of this thesis is to characterise the spatial variability of surface water fluxes as affected by chinooks over SSRB subbasins and ecozones. The objectives are addressed using detailed field observations and physically based land surface modelling. Eddy covariance was deployed at three prairie sites. During winter chinooks, energy for large evaporative fluxes were provided by downward sensible heat fluxes. There was no evidence of infiltration until March. The Canadian Land Surface Scheme (CLASS) coupled to the Prairie Blowing Snow Model (PBSM) was used as the modelling platform. A multi-physics version of CLASSPBSM was developed, consisting of two parameterisation options each for sixteen processes. Field observations were used to evaluate each of the configurations. Three parameterisations provide both best snow and best soil water simulations: iterative energy balance solution, air temperature and wind speed based fresh snow density and de Vries’ soil thermal conductivity. The model evaluation highlighted difficulties simulating evaporation and uncertainty in simulating infiltration into frozen soils at large scales. A single model configuration is selected for modelling the SSRB. Modelling showed that the SSRB generally experiences no net soil water storage change until March, confirming field observations. Chinooks generally reduce net terrestrial water storage, largely due to snowmelt and subsequent evaporation and runoff. The Prairie ecozone is that which is most strongly affected by chinooks. The Montane Cordillera ecozone is affected differently by chinooks; blowing snow transport increases during winter and runoff increases during spring. The Lower South Saskatchewan is the subbasin most affected by chinooks. The Red Deer is the subbasin least affected by chinooks.
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Rahman, Mohammed Mizanur. "Application of SWAT for Impact Analysis of Subsurface Drainage on Streamflows in a Snow Dominated Watershed." Thesis, North Dakota State University, 2011. https://hdl.handle.net/10365/29555.
Full textAbstract:
The wet weather pattern since the early 1990's has created two problems for the people living in the Red River Valley (RRV): (1) wet field conditions for farmers and (2) more frequent major spring floods in the Red River system. Farmers in the region are increasingly adopting subsurface drainage practice to remove excess water from their fields to mitigate the first problem. However, it is not clear whether subsurface drainage will deteriorate or mitigate the spring flood situation, the second problem. The Soil and Water Assessment Tool (SWAT) model was applied to evaluate the impacts of tile drainage on the Red River's streamflows. The model was calibrated and validated against monthly streamflows at the watershed scale and against daily tile flows at the field scale. The locations and areas of the existing and potential tile drained (PTD) areas were identified using a GIS based decision tree classification method. The existing and maximum PTD areas were found to be about 0.75 and 17.40% of the basin area, respectively. At the field scale, the range of Nash-Sutcliffe efficiency (NSE) for model calibration and validation was 0.34-0.63. At the watershed scale, the model showed satisfactory performance in simulating monthly streamflows with NSE ranging from 0.69 to 0.99, except that the model under-predicted the highest spring flood peak flows in three years. The results of modeling a 100% tiled experimental field showed that about 30-40% of water yield was produced as tile flow. Surface runoff and soil water content decreased about 34% and 19%, respectively, due to tile drainage. However, the impact of subsurface drainage on evapotranspiration (ET) and water yield was mixed. ET slightly decreased in a wet year and slightly increased in a dry year, while the pattern for water yield was opposite to that of ET. The watershed-scaled modeling results showed that a tiling rate of 0.75-5.70% would not have significant effects on the monthly average streamflows in the Red River at Fargo. For the 17.40% tiling rate, the streamflow in the Red River at Fargo might increase up to 1% in April and about 2% in Fall (September to November), while decreasing up to 5% in the remaining months. This SWAT modeling study helped to better understand the impact of subsurface drainage on the water balance and streamflows in the Red River of the North basin. The findings will also help watershed managers in making decisions for the purpose of managing agricultural drainage development in the RRV and other snow dominated watersheds around the world.
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Antifeau, Theodore Danial. "The significance of snow and arboreal lichen in the winter ecology of mountain caribou (Rangifer tarandus caribou) in the North Thompson Watershed of British Columbia." Thesis, University of British Columbia, 1987. http://hdl.handle.net/2429/26160.
Full textAbstract:
The winter ecology of mountain caribou (Rangifer tarandus caribou) in the North Thompson watershed of British Columbia was investigated over winters 1978-79 and 1979-80. The main objective of the study was to evaluate caribou movements and habitat use in relation to indices of energy cost of locomotion in snow and to forage availability, especially arboreal lichens. These data were collected in habitats from valley bottom to alpine throughout winter. Largely because of their high arboreal lichen productivity, mature forests are regarded by wildlife managers as essential winter habitat of caribou, leading to conflicts with forest harvesting. Data were compared between mature forests and other habitat types, to evaluate their importance to caribou.
An index of caribou locomotion cost in snow was caribou track depth in snow. A significant regression between caribou track depth and human sinking depth in snow permitted an estimate of caribou locomotion costs in all habitats. Locomotion costs often were greater in cutovers than in mature forests, and broadly increased with elevation; while temporal trends were cyclical, due to alternating accumulations of fresh, soft snow followed by settlement and maturation of the surface snow.
Analysis of fecal and rumen samples, and feeding-site inspections were used to determine caribou winter food habits. Arboreal lichens (Alectoria sp. and Bryoria spp.) dominated the diet by mid winter because terrestrial forage availability declined due to deep and crusted snowpacks. For each habitat, the absolute abundance of arboreal lichen was inventoried, and then this data together with snowpack measurements were used to estimate the relative availability of arboreal lichen over winter. Arboreal lichen availability was greatest in mature forests, and generally increased with elevation; it also increased within habitats as snow deepened and elevated caribou to higher forest canopy levels where greater quantities of lichen occurred.
For the first time, radio telemetry was used to determine mountain caribou movements and habitat use. Observations of non-radiocollared caribou were also used in some analyses.
In both used and unused habitats, estimated energy costs of locomotion and the availability of arboreal lichen were treated as indices of energy expenditure and of energy intake of foraging. These indices were qualitatively integrated in a net energy balance relationship to evaluate caribou movements and habitat use.
Caribou appeared to follow a general optimizing strategy, balancing their energy expenditure for locomotion in snow against the energy available from forage, when both terrestrial and arboreal forages are considered. Throughout winter, caribou preferably used mature forests, which offered much greater energetic benefits than cutovers and immature forests. As snow in subalpine (Engelmann Spruce - Subalpine Fir Zone) and alpine summer habitats deepened over early winter, caribou migrated to lower subalpine and lower slope and valley (Interior Cedar - Hemlock Zone), mature forest habitats. Caribou locomotion conditions and forage availability, primarily of terrestrial forages, were most favourable at these lower elevations, despite lower arboreal lichen availability, because of snowfall interception by the forest canopy and lower snowfall. Firmer, mid-winter snowpack conditions allowed caribou to reascend to late winter range in higher elevation subalpine forests, which, because of greater arboreal lichen availabilities combined with moderated locomotion conditions, became the most favourable habitats. Minor elevational shifts during this period occurred in response to fluctuations in locomotion conditions caused by cycles of snow accumulation and snow settlement. This study confirmed that mature forests are required habitat for caribou throughout winter, by providing critical arboreal lichen forage, and compared to cutovers, having lower locomotion costs and greater availability of terrestrial forage. Proposed forest reserves above 1680 m elevation in the upper subalpine are insufficient therefore to ensure essential caribou winter habitat. Mature forests from valley bottoms to the lower subalpine must also be reserved.Land and Food Systems, Faculty of
Graduate
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MacDonald, Ryan J., and University of Lethbridge Faculty of Arts and Science. "Modelling the potential impacts of climate change on snowpack in the St. Mary River watershed, Montana." Thesis, Lethbridge, Alta. : University of Lethbridge, Dept. of Geography, c2008, 2008. http://hdl.handle.net/10133/2511.
Full textAbstract:
Climate change poses significant threats to mountain ecosystems in North America (Barnett et al., 2005) and will subsequently impact water supply for human and ecosystem use. To assess these threats, we must have an understanding of the local variability in hydrometeorological conditions over the mountains. This thesis describes the continued development and application of a fine scale spatial hydrometeorological model, GENESYS (GENerate Earth SYstems Science input). The GENESYS model successfully simulated daily snowpack values for a 10 year trial period and annual runoff volumes for a thirty year period. Based on the results of these simulations the model was applied to estimate potential changes in snowpack over the St. Mary River watershed, Montana. GCM derived future climate scenarios were applied, representing a range of emissions controls and applied to perturb the 1961-90 climate record using the “delta” downscaling technique. The effects of these changes in climate were assessed for thirty year time slices centered on 2020s, 2050s, and 2080s. The GENESYS simulations of future climate showed that mountain snowpack was highly vulnerable to changes in temperature and to a lesser degree precipitation. A seasonal shift to an earlier onset of spring melt and an increase in the ratio of rain to snow occurred under all climate change scenarios. Results of mean and maximum snowpack were more variable and appeared to be highly dependent on scenario selection. The results demonstrated that although annual volume of available water from snowpack may increase, the seasonal distribution of available water may be significantly altered.viii, 93 leaves ; 29 cm
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Tahir, Adnan Ahmad. "Impact of climate change on the snow covers and glaciers in the Upper Indus River basin and its consequences on the water reservoirs (Tarbela reservoir) – Pakistan." Thesis, Montpellier 2, 2011. http://www.theses.fr/2011MON20056/document.
Full textAbstract:
L'économie du Pakistan, fondée sur l'agriculture, est hautement dépendante de l'approvisionnement en eau issu de la fonte de la neige et des glaciers du Haut Bassin de l'Indus (UIB) qui s'étend sur les chaînes de l'Himalaya, du Karakoram et de l'Hindukush. Il est par conséquent essentiel pour la gestion des ressources en eau d'appréhender la dynamique de la cryosphère (neige et glace), ainsi que les régimes hydrologiques de cette région dans le contexte de scénarios de changement climatique. La base de données satellitaire du produit de couverture neigeuse MODIS MOD10A2 a été utilisée de mars 2000 à décembre 2009 pour analyser la dynamique du couvert neigeux de l'UIB. Les données journalières de débits à 13 stations hydrométriques et de précipitation et température à 18 postes météorologiques ont été exploitées sur des périodes variables selon les stations pour étudier le régime hydro-climatique de la région. Les analyses satellitaires de la couverture neigeuse et glaciaire suggèrent une très légère extension de la cryosphère au cours de la dernière décade (2000‒2009) en contradiction avec la rapide fonte des glaciers observée dans la plupart des régions du monde. Le modèle « Snowmelt Runoff » (SRM), associé aux produits neige du capteur MODIS a été utilisé avec succès pour simuler les débits journaliers et étudier les impacts du changement climatique sur ces débits dans les sous-bassins à contribution nivo-glaciaire de l'UIB. L'application de SRM pour différents scénarios futurs de changement climatique indique un doublement des débits pour le milieu du siècle actuel. La variation des écoulement de l'UIB, la capacité décroissante des réservoirs existants (barrage de Tarbela) à cause de la sédimentation, ainsi que la demande croissante pour les différents usages de l'eau, laissent penser que de nouveaux réservoirs sont à envisager pour stocker les écoulements d'été et répondre aux nécessités de l'irrigation, de la production hydro-électrique, de la prévention des crues et de l'alimentation en eau domestiqueAgriculture based economy of Pakistan is highly dependent on the snow and glacier melt water supplies from the Upper Indus River Basin (UIB), situated in the Himalaya, Karakoram and Hindukush ranges. It is therefore essential to understand the cryosphere (snow and ice) dynamics and hydrological regime of this area under changed climate scenarios, for water resource management. The MODIS MOD10A2 remote-sensing database of snow cover products from March 2000 to December 2009 was selected to analyse the snow cover dynamics in the UIB. A database of daily flows from 13 hydrometric stations and climate data (precipitation and temperature) from 18 gauging stations, over different time periods for different stations, was made available to investigate the hydro-climatological regime in the area. Analysis of remotely sensed cryosphere (snow and ice cover) data during the last decade (2000‒2009) suggest a rather slight expansion of cryosphere in the area in contrast to most of the regions in the world where glaciers are melting rapidly. The Snowmelt Runoff Model (SRM) integrated with MODIS remote-sensing snow cover products was successfully used to simulate the daily discharges and to study the climate change impact on these discharges in the snow and glacier fed sub-catchments of UIB. The application of the SRM under future climate change scenarios indicates a doubling of summer runoff until the middle of this century. This variation in the Upper Indus River flow, decreasing capacity of existing reservoirs (Tarbela Dam) by sedimentation and the increasing demand of water uses suggests that new reservoirs shall be planned for summer flow storage to meet with the needs of irrigation supply, increasing power generation demand, flood control and water supply
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Burles, Katie, and University of Lethbridge Faculty of Arts and Science. "Snowmelt energy balance in a burned forest stand, Crowsnest Pass, Alberta." Thesis, Lethbridge, Alta. : University of Lethbridge, Dept. of Geography, 2010, 2010. http://hdl.handle.net/10133/2562.
Full textAbstract:
Forested watersheds in western North America are subject to significant change from natural and anthropogenic disturbance, including wildfire. Forest canopy changes have subsequent impacts on sub-canopy snow processes. A simple, process-based point energy balance model was developed to quantify differences in energy balance characteristics between a burned and a healthy forest stand. Potential model uncertainties were identified using sensitivity analyses. Simulated snowmelt accurately recreated measured snowmelt, providing confidence in the model’s ability to simulate energy balance processes in subcanopy environments where wind redistribution and sublimation are not major drivers of the local snowmelt energy balance. In the burned stand, sub-canopy snow accumulation was greater but melted more rapidly than in the healthy stand. The removal of forest canopy resulted in more energy available for snowmelt, including higher short-wave and lower long-wave radiation, and increased turbulent fluxes. Burned stands should be considered a separate land cover type in larger scale watershed models.xii, 129 leaves : ill,, map ; 29 cm
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Böckelmann, Uta [Verfasser]. "Description and characterization of bacteria attached to lotic organic aggregates (river snow) in the Elbe River of Germany and the South Saskatchewan River of Canada / vorgelegt von Uta Böckelmann." 2001. http://d-nb.info/96442097X/34.
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Khan, Mohammad Inamullah. "The effects of snow avalanches on the hydrologic regime of the Kunhar river, Western Himalayan, Pakistan : analysis and application to river flow forecasting." Thesis, 1995. http://hdl.handle.net/2429/4315.
Full textAbstract:
This study sets out to investigate the significance of snow avalanches on the hydrology
and runoff generation in the Kunhar basin in Northern Pakistan. The objectives of this
research are, to analyze the snowmelt and snow avalanche effects using the U.B.C.
Watershed Model, and to produce a flow forecasting system which takes account of the
snow avalanche effects.
The Kunhar River is a major tributary of the Jhelum River in the western
Himalayas of Pakistan. The basin area is about 2,340 km2 with an elevation range from
800 to 5,300 m above sea level. The watershed has a seasonal snow cover which
develops from early November onwards, reaching a maximum depth in March or April.
Also, the snowpack increases greatly at upper elevations.
In the Kunhar basin the avalanching is a major source of snow redistribution from
higher to lower elevations. It is estimated that on average over 200 x 106m3 water
equivalent of snow is avalanched annually. The percentage of the total affected area
(runout and starting zones) by avalanches in Kunhar basin is estimated to range from
12% to 21%. The starting zone lies at a mean elevation of about 4,000 m and runout
zones are at mean elevations of 2,450 and 2,800 m above sea level. This means that the
avalanche activities in the lower elevations are dependent on the snow precipitation at
elevation 4,000 m. This study shows that about 20% of the snowpack at 4,000 m is, on
average, subject to avalanching. Avalanche contribution is found to be very significant in calibrating the
watershed model. On average the overall Nash-Sutcliffe coefficient of efficiency of the
model was improved from 77 to 84% after introducing avalanches in the calibration
which shows improved time distribution of runoff.
Snowmelt pattern in the avalanche areas is significantly modified by avalanche
activity. Firstly, the snowmelt in the runout zones starts about seven days later and lasts
about 30 days more than in areas not affected by avalanches. The snowmelt volume in
runout areas is increased by about 200 to 300% in affected areas. The maximum
snowmelt from the avalanche runout areas is about 100% higher than the maximum
snowmelt in the un-affected areas. The timing of the maximum snowmelt is delayed by
about 15 days in the runout zones of avalanche affected area, due to high accumulation of
snow. These results show that the snow avalanches increase both the volume and the
period of the snowmelt in the runout zones and also change the time distribution of the
snowmelt. Since the snowmelt increase in the runout zones is compensated by the
decrease in snow in affected areas of the starting zones, the total snow melt from the
basin is unchanged.
The above results of flow simulation by using redistribution of snow were used to
produce a forecasting system of avalanche activity. Linear regression analyses were
performed and the linear relationships for each band were estimated. Regression analyses
show very strong correlation between avalanche volume and snowpack accumulation at
the upper elevations, i.e., the coefficient of determination (R2) is found to be in a range of
0.9 - 0.95. The extra snow depth acquired at elevations 2,450 to 2,800 m in the form of avalanche is also strongly correlated with the existing snow depth at 4,000 m, R2 ranged
between 0.93 and 0.99.
If the snowpack at 4,000 ra elevation is measured then the maximum snow
accumulation, which occurs in late March or early April, can be estimated. From the
developed equations the total avalanche volume, the snow avalanche depth, and the
affected areas for runout and starting zones can be estimated. These estimates can then be
used in the U.B.C. Watershed Model to forecast the flow for the coming season.
Application of this procedure showed that the proposed forecasting system gives an
improved and reliable estimation of the seasonal flow volume and the time distribution of
runoff for the Kunhar river.
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Yao-cheng, Liao, and 廖堯震. "The Study of Wan Shen’s‘Misty River, Layered Peaks’ and ‘Light Snow on a Fishing Village’." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/03415871515976119896.
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Bowen, Amanda Kate. "North Platte Snowpack Reconstructions Using Dendrochronology." 2011. http://trace.tennessee.edu/utk_gradthes/859.
Full textAbstract:
April 1st Snow Water Equivalent (SWE) reconstructions were generated using tree-ring chronologies for the Upper North Platte River Basin (UNPRB), located in north-central Colorado and south-eastern Wyoming. To regionalize April 1st snowpack data from 11 SNOw TELemetry stations (SNOTEL stations), Varimax Rotated Principal Components Analysis (PCA) was used. For the 11 station regionalization, the reconstruction explained 42% of the variance in the instrumental record and extended the record to 1378 (632 years). Retained tree-ring chronologies included those that were stable and positively correlated at 99% confidence levels or higher with the regional snowpack data for a 60–year overlapping period of record from 1940 to 1999. Stepwise Linear Regression was performed for the overlapping (calibration) period to develop regression models for the reconstructions. Eleven stations were individually reconstructed of which three stations (Dry Lake, Old Battle, and Lake Irene) explained variances greater than 40%. A contour plot of the R2 values for all 11 stations revealed that the more statistically skillful reconstructions were for stations spatially adjacent to the tree-ring chronologies used in the regression models. When the two individual stations with the lowest explained variance were removed from the 11 station snowpack regionalization, the new nine station regionalization reconstruction explained 45% of the variance over the same 632 year period.
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Behrawan, Houshang [Verfasser]. "Hydrological snowmelt modelling in snow covered river basins be means of geographic information system and remote sensing : case study - Latyan catchment in Iran / von Houshang Behrawan." 2010. http://d-nb.info/1010541102/34.
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Hintnaus, Ivo. "Vliv sněhové pokrývky na odtok vody z povodí v zalesněném a nezalesněném prostředí." Master's thesis, 2011. http://www.nusl.cz/ntk/nusl-312277.
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This work deals with the evaluation of snow cover and snow spatial distribution in experimental Zbytinský and Tetřivči stream basin. Snow mesaurements were focused on snow depth and a snow water equivalent. Interpolation metods and detailed monitoring of rainfall-flow process were applied in the period of the winter half-year 2009 - 2011. The effects of geografic factors on spatial distribution of snow cover in the accumulation period and in the snow melting period were analysed. The analysis of physical geografic factors effect was focused on vegetation, exposure, slope, wind flow and shading. Results confirmed the strong effect of vegetation in the accumulation and snow melting period. Other physical geografic effects on spatial distribution of snow cover were not so significant. The model HEC-HMS was applied to determine the runoff in both stream basins. Simulations result in the winter half-year period reached good agreement between observed and simulated hydrographs. Effects of snow cover contribution to runoff in the snow melting period in wooded Tetřívčí stream basin and also in antropogenic Zbytinský stream basin were proved based on simulations of outflow and snow water equivalent. Key words: snow depth, snow water equivalent, HEC-HMS, Blanice River basin, Zbytinský stream, Tetřívčí stream
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Welsh, Cedar. "Multi-century records of hydroclimate dynamics and steelhead trout abundance from tree rings in northern British Columbia, Canada." Thesis, 2019. http://hdl.handle.net/1828/11378.
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The impacts of climate variability and change on streamflow are of increasing concern, particularly as human demands on water supplies compete with the needs of natural ecosystems. The consequences on the hydrological cycle are predicted to be most severe for mid- to high-latitude regions. Of particular concern is reduced mountain snow accumulation and related reductions in the snow- and glacier-derived water supply. In northern British Columbia (BC), recent snowpack declines have caused a unique water management challenge. Diminishing water security in a region considered water-abundant has intensified over the last decade. Characterizing the climate controls on hydrologic variability is a priority for developing baseline information required for water supply forecasting. This research focuses on developing multi-century, annually-resolved records of snow water equivalent (SWE) and streamflow to provide a better understanding of long-term hydroclimate variability for the design and implementation of management strategies that balance riverine ecosystem services, such as recreation and fish habitat, with increasing economic and social demands.
Climate sensitive tree-ring chronologies provide the opportunity to extend instrumental records of hydroclimate by capitalizing on the influence of climate on both annual radial growth and seasonal runoff. Traditional dendrohydrology relies on moisture-limited tree species from dry, continental settings. This dissertation presents a new method by focusing on mid- to high-elevation conifers sensitive to snowpack variability. Ring-width and maximum latewood density records from mountain hemlock (Tsuga mertensiana (Bong.) Carriere), white spruce (P. glauca (Moench) Voss), and subalpine fir (Abies lasiocarpa (Hook.) Nutt.) stands were collected at sites in northern BC. Dendrochronological techniques were used to develop a: 1) 223-year record of April 1 SWE for the Stikine River basin; 2) 417-, 716-, and 343-year record of summer streamflow for the Skeena, Nass and Stikine rivers, respectively; and, 3) a 193-year reconstruction of summer-run Skeena River steelhead abundance based on the influence of ocean-atmospheric forcings on both radial tree growth and steelhead escapement. The April 1 SWE record suggests that there has been considerable variability in snowpack levels in the Stikine basin and a distinct in-phase relationship with seasonalized Pacific Decadal Oscillation (PDO) indices, not seen in basins to the south. The summer streamflow records also support a north-south “see-saw” effect, suggesting an association between moisture transport and atmospheric-ocean circulation in the region. In addition to the snow-sensitive tree-ring data, the streamflow models incorporated paleo-hemispheric records to improve predictive skill. Finally, the steelhead model described alternating intervals of persistently above-average and below-average abundance that corresponded to oceanic PDO-like influences and describe links to “warm-warm” ENSO-PDO years associated with in-river low flow periods.
The reconstructions suggest that: 1) recent snowpack and streamflow declines are a rare event over a multi-century context; and, 2) existing instrumental records do not adequately represent the historic range of basin-specific hydroclimate variability necessary for new planning horizons. Mid- to high-elevation, snow-sensitive conifers have strong potential as paleohydrological proxies and for expanding the application of dendrohydrology to non-arid settings. Current conditions in northern BC, compounded by land use changes and climate change, are predicted to become more severe in the future. It is important that planning regimes incorporate long-term hydroclimate data to better understand and quantify how water supply and ecosystems will respond to future changes.Graduate
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Sproles, Eric Allan. "Climate change impacts on mountain snowpack presented in a knowledge to action framework." Thesis, 2012. http://hdl.handle.net/1957/28640.
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Throughout many of the world’s mountain ranges snowpack accumulates during the winter and into the spring, providing a natural reservoir for water. As this reservoir melts, it fills streams and recharges groundwater for over 1 billion people globally. Despite its importance to water resources, our understanding of the storage capacity of mountain snowpack is incomplete. This partial knowledge limits our abilities to assess the impact that projected climate conditions will have on mountain snowpack and water resources.
While understanding the effect of projected climate on mountain snowpack is a global question, it can be best understood at the basin scale. It is at this level that decision makers and water resource managers base their decisions and require a clarified understanding of basin's mountain snowpack. The McKenzie River Basin located in the central-western Cascades of Oregon exhibits characteristics typical of many mountain river systems globally and in the Pacific Northwestern United States. Here snowmelt provides critical water supply for hydropower, agriculture, ecosystems, recreation, and municipalities. While there is a surplus of water in winter, the summer months see flows reach a minimum and the same groups have to compete for a limited supply.
Throughout the Pacific Northwestern United States, current analyses and those of projected future climate change impacts show rising temperatures, diminished snowpacks, and declining summertime streamflow. The impacts of climate change on water resources presents new challenges and requires fresh approaches to understanding problems that are only beginning to be recognized. Climate change also presents challenges to decision makers who need new kinds of climate and water information, and will need the scientific research community to help provide improved means of knowledge transfer.
This dissertation quantified the basin-wide distribution of snowpack across multiple decades in present and in projected climate conditions, describing a 56% decrease in mountain snowpack with regional projected temperature increases. These results were used to develop a probabilistic understanding of snowpack in projected climates. This section described a significant shift in statistical relations of snowpack. One that would be statistically likely to accumulate every 3 out of 4 years would accumulate in 1 out of 20 years. Finally this research identifies methods to improved knowledge transfer from the research community to water resource professionals. Implementation of these recommendations would enable a more effective means of dissemination to stakeholders and policy makers.
While this research focused only on the McKenzie River Basin, it has regional applications. Processes affecting snowpack in the McKenzie River Basin are similar to those in many other maritime, forested Pacific Northwest watersheds. The framework of this research could also be applied to regions outside of the Pacific Northwestern United States to gain a similar level of understanding of climate impacts on mountain snowpack.Graduation date: 2012
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Kocum, Jan. "Tvorba odtoku a jeho dynamika v pramenné oblasti Otavy." Doctoral thesis, 2012. http://www.nusl.cz/ntk/nusl-305924.
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In context of catastrophic floods and extreme droughts in recent years there is an urgent need of solving of issues dealing with protection against hydrological extremes, not using just classical engineering methods but also untraditional practices. There is a new protection strategy focusing on gradual increase of river catchment retention capacity including its headwater regions. All of the issues related to various possibilities and measures leading to river headstream areas retention capacity increase should be discussed by experts in various fields taking into account objectives and priorities of a supra-regional, regional and local significance. Natural runoff process is affected by man already by its birth, thus in headwaters where numerous procedures related to runoff retardation and water retention increase in headstream areas could be realized. Suitable conditions for the research realization at present is related to the Otava River headwaters (sw. Czechia) representing the core zone of a number of extreme runoff events and with high heterogeneity in the terms of physical-geographic and socio-economic aspects. To understand and clarify the runoff generation process and the effect of various physical-geographic factors on its dynamics, the detailed analyses of runoff regime in chosen...