Dissertations / Theses on the topic 'Upland rivers'

The characteristics of gravel-bed river deposits vary according to the complex relationships between hydrological and sedimentological regimes that occur over a range of spatial and temporal scales. This thesis concerns the composition and distribution of fine-grained sediment in British upland rivers; the size fractions which are perhaps the most susceptible, as regards both quantity and quality, to human activity and yet which can yield important information regarding upstream geological characteristics.

The increasing number and scale of river impoundments throughout the 19th and 20th centuries means that the management of these impoundments is crucial to the future of global riverine biota. Impoundments such as reservoirs can affect rivers in a variety of ways, not least through the reduction in amplitude of the natural hydrograph, depriving rivers of ecologically important spate flows. Many reservoir operators conduct regular safety tests, known as scour releases, during which large quantities of impounded water are released directly into rivers. This project assesses the impact of these releases on the hydrology and physio-chemistry of the receiving water bodies as well as upon fish movements and benthic macroinvertebrate abundance and diversity downstream of the reservoirs. The potential of such releases to mimic natural spate flows for ecological gain is also examined. The work took place in the Yorkshire Water catchment area in northern England between 2007 and 2010. Passive Integrated Transponder (PIT) telemetry was used to assess the responses of brown trout Salmo trutta to these short-duration releases. Tagged fish were able to maintain position during the releases and showed no evidence of wash-out or upstream migratory movements associated with the releases. Changes to macroinvertebrate abundance, diversity and community structure associated with the release were also examined. Some sites showed significant wash-out and community change following the releases while other sites were unchanged. Communities at impacted sites returned to pre-release structures within weeks of the releases. Analysis of habitat use and characteristics suggest the responses of fish and macroinvertebrates to these reservoir releases were linked to habitat heterogeneity and the use of flow refugia. The negative impacts associated with the scour releases were minimal, while mimicked spate releases may improve salmonid spawning habitat and could re-introduce valuable flow variability to impounded catchments.

Thesis (MScConEcol)--Stellenbosch University, 2014.
ENGLISH ABSTRACT: Restoration practices commonly make use of a reference condition in order to restore a site to a better ecological state than it is currently in. The selection process and relevance of the reference condition has not yet been tested in upland Western Cape rivers especially with relation to spatial and temporal scales. This thesis sought to evaluate whether space (longitudinal) and time (temporal) influence riparian plant community composition (laterally), how it influences the community composition and whether these differences impacts the selection of a reference condition used in restoration practices. In order to investigate the role longitudinal position, sites were selected across three longitudinal zones: mountain stream, transitional and upper foothills. Historic sites used in a previous study on riparian vegetation of upland rivers were resampled and datasets used for temporal comparisons between undisturbed sites, sites recovering after clearing of invasive alien plants and sites affected by fire. Riparian vegetation communities showed differences between longitudinal zones, basins and rivers. The species responsible for marginal zone identity (plants in close proximity to the active channel), determined using relative cover abundance varied, with Isolepis prolifera responsible for the group identity in the mountain stream and transitional sites but in the foothills Calopsis paniculata, Drosera capensis and Metrosideros angustifolia saplings were responsible for lateral zone identity. The lower dynamic (transitional between wet and drybank) had no similarities between different longitudinal zones across rivers. In the lower zone Pteridium aqualinum was mostly responsible for the identity. The upper bank had no single species responsible for group identity. The species described to be typical for the reference condition on these particular rivers by other studies were mostly present in the comparable lateral zone but it was however not always responsible for the identity of the specific lateral zone. By comparing selected environmental variables such as horizontal distance from active channel, elevation and substrate calibre with different longitudinal zones’ riparian vegetation species distribution, different combinations were produced. The mountain streams showed the strongest relationship with horizontal distance and elevation in combination to one another and the upper foothills horizontal distance from the active channel was linked most strongly to vegetation positioning. These results confirm the importance of space when attempting to assess, study or restore riparian communities. Temporally, sites had stronger similarity to data collected during the same sampling period than with historic data. Also, the overall relative species abundance did not show significant change to be present at a site scale. The changes in community composition were found to be due to a lateral zone scale variation in species abundance. As expected the undisturbed rivers showed less variation in species responsible for temporal changes than the recovering and fire-exposed rivers. Species responsible for changes in relative abundance at a lateral zone scale were Metrosideros angustifolia, Morella serrata, Brabejum stellatifolium, Isolepis prolifera, Elegia capensis, Prionium serratum and Calopsis paniculata. Due to the species diversity not changing much temporally but the relative abundance of specific species showing much variation over time it can be concluded that the changes are not diversity based but instead driven by changes in relative abundances of species typical for a lateral zone. The spatial and temporal variation in riparian vegetation community composition was found to be significant enough to suggest that the use of a fixed reference condition for all Western Cape rivers would not be feasible due to clear differences between basins. Secondly when selecting a reference site the spatial location of this site should be within the same longitudinal zone since bank shape does influence riparian plant species distribution. Finally the temporal comparison between sites showed high diversity in species abundances but small differences in diversity overall. This would suggest that a general community description specific to 1) where the site is situated and 2) based on the present riparian vegetation community composition within a specific basin may be more realistic and achievable for restoration and environmental management purposes as opposed to using site descriptions from the past and reference sites too far upstream or downstream from the restoration site.
AFRIKAANSE OPSOMMING: Herstel praktyke maak algemeen gebruik van 'n verwysing toestand om 'n terrein te herstel na 'n beter ekologiese toestand as wat dit tans is. Die keuringsproses en relevansie van die verwysing toestand is nog nie in die boonste gedeeltes van Wes-Kaap Riviere getoets nie, veral met betrekking tot ruimtelike en tydskale nie. Hierdie tesis het gesoek om te evalueer of ruimte (longitudinaal) en tyd (temporaal) rivieroewers plant gemeenskap samestelling (lateraal) beïnvloed en of hierdie verskille die keuse van 'n verwysing toestand in die herstel praktyke beïnvloed. Ondersoek terreine was oor drie longitudinale sones geselekteer: berg stroom, oorgangs en boonste hange terreine. Historiese terreine was weer ondersoek en die datastelle was gebruik vir die temporale vergelykings tussen onversteurde terreine, terreine wat herstel na die skoonmaak van indringer spesies en wat geraak was deur 'n brand. Oewerplantegroei gemeenskappe het verskille tussen longitudinale sones, rivier-kom en rivier takke gewys. Die spesies wat verantwoordelik was vir marginale zone (plante in nabye afstand met die aktiewe rivier kanaal) identiteit, bepaal met behulp van relatiewe dekking hoeveelheid, het gevarieer met Isolepis prolifera verantwoordelik vir die groep identiteit in die berg stroom en oorgangs trerreine, maar in die boonste hange was dit Calopsis paniculata, Drossera capensis en Metrosideros angustifolia boompies wat verantwoordelik was vir die laterale sone identiteit. Die laer dinamiese area het geen ooreenkomste tussen marginale gebiede van verskillende longitudinale sones gehad nie. In die onderste sone was Pteridium aqualinum meestal verantwoordelik vir die groepering se identiteit. Die boonste bank het nie 'n enkele spesie wat verantwoordelik was vir die groep identiteit gehad nie. Die spesies beskryf as tipies vir die laterale sone deur Reinecke et al. (2007) was meestal teenwoordig in die beskryfde laterale sone van hierdie studie, maar dit was egter nie altyd verantwoordelik vir die identiteit van die laterale sone gemeenskap nie. Verskillende lengte sones het gekorreleer met verskillende omgewingsveranderlikes wat sterkste gekoppel kon word aan die verspreiding van spesies. Die bergstrome het die sterkste verhouding met horisontale afstand en hoogte in kombinasie met mekaar gehad en in die boonste hange was horisontale afstand van die aktiewe kanaal die sterkste gekoppel aan plantegroei posisie. Die belangrikheid van ruimte is onmiskenbaar ten opsigte van evaluering, bestudering en die herstel van rivieroewers gemeenskappe. Terreine het sterker ooreenkoms met data gehad wat tydens dieselfde tydperk versamel was, as met historiese data. Die algehele relatiewe spesies hoeveelheid het egter nie beduidende verandering getoon op 'n terrein skaal nie. Soos verwag was het die onversteurde riviere minder temporale variasie in spesies getoon as die herstellende en brand blootgestelde riviere. Spesies wat verantwoordelik was vir die verandering in relatiewe hoeveelhede op 'n laterale sone skaal was M. angustifolia, Morella serrata, Brabejum stellatifolium, I. prolifera, Elegia capensis, Prionium serratum en C. paniculata. As gevolg van die diversiteit van spesies wat nie baie verander het tydelik nie, maar die relatiewe hoeveelheid van spesifieke spesies wat heelwat variasie oor tyd getoon het, kan dit afgelei word dat die veranderinge nie diversiteit gebaseerd was nie, maar eerder gedryf was deur veranderinge in relatiewe hoeveelhede van tipiese spesies in 'n laterale sone. Die ruimtelike en tydelike variasie in oewerplantegroei gemeenskap samestelling was beduidende genoeg om voor te stel dat die gebruik van 'n vaste verwysing toestand vir alle Wes-Kaapse riviere nie haalbaar sou wees nie as gevolg van duidelike verskille tussen riviere. Tweedens, by die kies van 'n verwysing terrein moet die ruimtelike plek van hierdie terrein in dieselfde lengte sone wees aangesien bank vorm 'n invloed op rivieroewer plant verspreiding het. Laaastens, het die tydelike vergelyking tussen terreine hoë diversiteit in spesies verspreidings maar klein verskille in algehele diversiteit gehad. Dit stel voor dat 'n algemene beskrywing van die gemeenskap wat spesifiek op 1) waar die terrein geleë is en 2) gebaseer op die huidige oewerplantegroei gemeenskap samestelling binne 'n spesifieke rivier netwerk dalk meer realisties en haalbaar vir hersteel en bestuurs doeleindes sou wees. Hierdie benadering word verkies bo die gebruik van n terrein beskrywings uit die verlede en verwysing terreine te ver stroomop of stroomaf van die herstel gebied.

There is limited knowledge and understanding of the role of nutrients and effect of herbivore grazing on epilithon production in Australian upland rivers. Before investigating these processes, a method was required that will allow the study of factors (physical, chemical and biological) that affect epilithon abundance and distribution in lotic systems. The Thredbo River, Kosciusko National Park, New South Wales, provided an opportunity to conduct this investigation because it: is relatively undisturbed; has been intensely studied; is easily accessed; and is of appropriate width and depth to conduct in-stream experiments. The specific goals of this research were the: (1) validation of the nutrient-diffusing substrate method for investigating epilithon responses to nutrients; (2) development of experimental channels in which to investigate nutrient/epilithon dynamics in an upland stream; (3) development of a method to inhibit macroinvertebrate grazing from in situ experimental channels, so that epilithon responses to nutrients with and without grazing pressure can be studied; and (4) assessment of the ecological implications of nutrient/ epilithon/macroinvertebrate interactions assessed from in-stream experiments. Major achievements of my research, that advance the study of stream ecology, are as follows: · The investigation of the features of nutrient release from terracotta nutrientdiffusing substrates showed that phosphorus does not readily diffuse through terracotta clay, probably because terracotta contains known binding agents for phosphorus, such as iron, and because pores are easily blocked. I concluded that this type of substrate is inappropriate for studying nutrient dynamics and epilithon responses to the nutrient(s) limiting growth. The outcomes of this research has implications for future research using nutrient-diffusing substrates, and of how nutrient limitation information is interpreted from past research using terracotta nutrient-diffusing substrates. · I designed and tested in-stream experimental channels that were functional and provided near natural conditions for studying the interactions between nutrients/ epilithon/macroinvertebrates, without affecting physical variables not tested for. The in situ method developed was successful in simulating 'real world' complexities. Clay paving bricks were used as standardized common surface for community development because their colour, size and surface texture are similar to those of natural stones. · I developed a technique for successfully inhibiting macroinvertebrate grazing from designated areas, using electricity, without affecting flow and light. This technique will enable in-stream herbivory studies to assess the effects of macroinvertebrate grazing pressure on epilithon under natural conditions, including variability in flow, temperature, light and nutrients. It will allow the vexed question of whether epilithon biomass is controlled by bottom-up or top-down processes to be objectively addressed. The construction of in situ experimental channels that simulate natural conditions, combined with the non-intrusive methods of macroinvertebrate exclusion and nutrient addition, resulted in a study design that will facilitate the investigation of biotic responses to nutrients in Australian upland streams. Using the method developed, I showed that variable flows in the upper Thredbo River appear high enough to slough epilithon, but not high enough to dislodge macroinvertebrates. This may mean that in systems such as the Thredbo River that experience frequent low level disturbance, the epilithon is unable to reach equilibrium. There is strong top-down control of epilithon in this stream, with nutrients, temperature and light playing a secondary role. I concluded that natural variability may be more important than previously considered and perhaps this, rather than constancy, should be studied. This thesis adds support to the continuance of multiple factor investigations, and advocates that such studies be conducted under natural conditions so that the results are more relevant to natural systems than from studies conducted in controlled laboratory and outdoor artificial streams. Clearly, the in-stream channels, developed as part of the current research, will allow research that contributes to our understanding of community responses to the physical, chemical and biological processes operating in lotic environments.

The American signal crayfish Pacifastacus lernusculus, an invasive species widely introduced throughout Europe, is a major threat to native European crayfish species and is causing increasing concern because of its wide impact on aquatic ecosystems. This thesis investigates the within catchment expansion of signal crayfish populations in two upland rivers and the spatial ecology and movement of the introduced signal crayfish and the indigenous white-clawed crayfish Austropotamobius pallipes. Populations of signal crayfish are established and expanding on the upland rivers Wharfe and Ure. On the Wharfe the signal crayfish population is well established and now occupies about 30 km of river and is currently expanding at a rate in excess of 2 km year(^-1). On the Ure the signal crayfish population is younger and currently occupies 1.6 km and is currently expanding at about 0.5 km year(^-1). The range expansion is biased towards downstream in both rivers, by a ratio of about 3:1 (downstream:upstream).The movements and dispersal of white-clawed and signal crayfish was studied utilising a combination of radiotelemetry and internal and external Passive Integrated Transponder (PIT) tags. Radiotagged adult signal crayfish were capable of substantial active movements (maximum movement 790m in 79 days). The level of movement of adults suggests they may have the potential to be responsible for the observed rates of population expansion. Although the movements of radiotagged adult signal crayfish within main river channel were equally distributed upstream and downstream, in-stream barriers both natural and artificial were found to limit the upstream movements of PIT tagged crayfish and this may contribute to the observed downstream bias of signal crayfish population expansion. The movements and dispersal of PIT tagged white-clawed crayfish within a small upland high gradient stream were strongly biased towards downstream. Maximum movement of radiotagged adult signal crayfish occurred during midsummer. Temperature appeared to be a major factor influencing the timing and extent of movements between tracking periods although there was a large variation between individuals. All significant downstream movements made by crayfish were active movements and not the result of passive movement during periods of high discharge. There were no sex or size differences in the dispersal and movement of radiotagged and PIT tagged signal crayfish whilst in PIT tagged white-clawed crayfish size, sex, injuries and duration of tracking influenced extent of movement. The expansion of the signal crayfish population in the River Wharfe appears to lead to the progressive loss of white-clawed crayfish populations where they come into direct contact. Limited differences in the microhabitat utilised by the two species were found where the species were syntopic, suggesting the potential exists for direct competition between the two species. In addition signal crayfish showed greater movement and dispersal than white-clawed crayfish. This may contribute to the ability of signal crayfish to colonise rivers rapidly and may also offer a competitive advantage over white-clawed crayfish thus contributing to the observed replacement. The results are discussed in the context of the conservation and management of crayfish and the ecology of invasive species.

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.

Because the Coastal Plain of southeastern Virginia has not been extensively studied, thirty random samples associated with Blackwater and Nottoway rivers were collected in the spring of 1987 from Surry, Sussex, and Southampton counties. Soil classification as well as mineralogical, chemical, and physical analysis were conducted for all samples.

The purposes of this investigation were to: (1)classify the soils in this area, (2) determine the distribution of sand and clay minerals, (3) examine the weathering effect on clay minerals on different position of the landscape for different parent material sources.

The soils examined classified as follow: Aquic Hapludults 43% > Typic Hapludults 26.6% > Ultic Hapludalfs 10% > Humic Hapludults 3% = Typic Rhodudlts 3% = Aquic Hapludalfs 3% = Typic Udipsamment 3% = Typic Quartzpsamment 3% = Psammentic Hapludalfs. Qualitative analysis of clay minerals revealed that kaolinite and hydroxy interlayer vermiculite were the dominant clay minerals; that montmorillonite, mica, gibbsite quartz, and vermiculite were of lesser quantities; that chlorite, feldspar and interstratified minerals were of trace amounts. Kaolinite represents about 21-70%, HlV 11-60%, montmorillonite 0-20%, mica 0-16%, gibbsite 0-13%, quartz 1-12%, and vermiculite 0-10%. The presence of these minerals were mainly related to the acid reaction of the soil media, which was essentially attributed to Al and H ions in soil solution. From the past history and geological composition of the Piedmont it is assumed that kaolinitic minerals were transported and sedimented in the Coastal Plain. Hydroxy-interlayer vermiculite minerals was weathering from vermiculite because most of the Al was adsorbed by vermiculite to form HIV. Therfore, gibbsite was not precipitated. Montmorillonite was assumed to have formed from mica minerals. That was substantiated by statistical analysis which showed a high negative correlation between gibbsite and vermiculite (r=0.46, n=30) and between montmorillonite and mica (r=-0.6, n=10).

Master of Science

River confluences are common features of the landscape as a result of the dendritic nature of river catchments. Much of the research to date has investigated flow at lowland confluences, whereas the most dynamic river confluences are likely to be found in upland areas. Therefore, in order to improve the understanding of the flow, sediment transport and morphological processes at river confluences, it is necessary to investigate the applicability of the findings from lowland confluences to their upland counterparts. This thesis uses field and numerical modelling experiments to increase the understanding of the dynamics of these upland river confluences. Flow and particle tracking data have been obtained from two different field sites: the more stable upland river confluences of Moor House National Nature Reserve and the steeper confluences of the Borgne d’Arolla braid plain. These data have been used to test two new numerical modelling developments. The first is the application of an explicit free surface model within a Computational Fluid Dynamics framework to enable the simulation of flow in natural rivers with steep water surface slopes. The second is the development of a new, reduced-complexity Discrete Particle Model that uses the three-dimensional flow data to simulate individual particle trajectories and the Generalised Likelihood Uncertainty Estimation method to estimate the uncertainty in these trajectories. There are three main findings in this thesis. Firstly, at upland confluences changes in the flow direction over the less well-defined banks have the greatest impact on individual particle trajectories and thus the morphological evolution of these confluences. Secondly, as water surface slopes increase, topographic features have less impact on the flow field than undulations in the water surface. Finally, turbulent flow structures and helical flow cells are found to be less important for the dynamics of these upland river confluences.

Hydrogeologic investigations were conducted on the drainage systems of an area of the Pennyroyal sinkhole plain of south central Kentucky. The degree of karstification of five area streams was studied to develop an understanding of the evolution of drainage as the landscape changes from a sandstone caprock plateau to a limestone sinkhole plain. The Chester Upland, capped by the Big Clifty Sandstone, possesses predominantly surface drainage and the Pennyroyal Plain, formed on Mississippian limestones, possesses considerable subsurface drainage. As the Chester Upland Escarpment retreats and surface streams are onto the limestones, the streams evolve to become subsurface streams. The five streams observed in the study (all flowing on limestones) demonstrated less karst development close to the Chester Escarpment and more karst development with increasing distance from the escarpment. Sediments derived from the escarpment and plateau blanket the stream beds thus perching the streams and preventing chemically aggressive water from forming karst solution features in the limestones. The streams farther away from the escarpment are removed from the sediment source and are therefore able to downcut into the limestone and invade the subsurface to become cave streams. Lithologic investigation of limestones exposed in stream beds revealed that minor resistant units can act to diminish downcutting and maintain short sections of surface flow. The stream investigated was not flowing on a perching layer, but instead was held on the surface by a stratigraphic control (spillover layer) that prevented subterranean stream invasion. Dye traces conducted on groundwater flow in the sinkhole plain revealed that the area drainage pattern is changing as surface streams invade the subsurface and that integration between drainage basins is taking place. Stream piracy and stream diversion are occurring in the subsurface causing alteration of the existing topographic drainage divides that developed before the surface streams invaded the subsurface. A general model is presented which shows the evolution of surface drainage to subsurface drainage, as the Chester Escarpment continues its northwestward retreat.

Degraded rangelands and riparian woodlands in eastern North Dakota are increasing in frequency. Two studies were conducted to address reduced forage quantity and quality and reduced regeneration of riparian tree and shrub species. Research objectives were to (1) analyze multiple pre-seeding treatments to determine impacts on rangeland production of interseeded native species; and (2) determine if fencing, weed-barrier fabric, mowing, or herbicide treatments can increase survivability of riparian tree and shrub seedling plantings. Pre-seeding treatments with herbicide showed significantly higher production of native species than the control. High-fencing/mowing treatment and high-fencing/weed-barrier fabric/herbicide treatment in riparian tree and shrub plantings resulted in significantly higher survival than the control. These findings will be used to develop future research and management strategies.
Robert H. Levis II Cross Ranch Fellowship
Gladys Allen Trust of St. Louis
Red River Regional Council
North Dakota Department of Health
Environmental Protection Agency (EPA)

Coarse sediment transfer in upland gravel-bed river systems is often neglected in the design and operation of river management schemes. Yet, it is increasingly attributed to problems within upland environments including bank erosion and enhanced flood risk. Developing a sufficient understanding of coarse sediment transfer and channel change requires strategic field monitoring. Predicting future channel change and flood risk under varying management options requires numerical modelling. This thesis employs a combined field monitoring and numerical modelling approach to explore the relationship between coarse sediment transfer, lateral channel change, river engineering and flood risk. Intensive field monitoring is used to understand sediment transfer and channel change. Methods include repeat cross-sectional resurvey, bank erosion pins and bank-top surveys, and sediment impact sensors. These data are used to illustrate the spatial and temporal variability of in-channel sedimentation and rates and mechanisms of bank erosion. When analysed further, these data explain patterns of sedimentation and demonstrate implications of coarse sediment accumulation for flood risk. The data are then used in the development and application of a quasi two-dimensional model of channel change. The model couples a one-dimensional sediment routing model with a lateral adjustment component to simulate patterns of downstream fining alongside vertical and lateral channel changes. By using a split channel approach, asymmetrical width adjustments are simulated based on critical shear stress thresholds. Lateral differences in bed elevation and curvature are used to distribute shear stress across the channel. Simulations are run to explore scenarios including changing the flow regime, removing bank protection and implementing a river engineering scheme on a reach with high sedimentation and bank erosion problems. The results highlight the potential impact that poor river management can have on upland rivers, demonstrating enhanced bank erosion upstream and greater sedimentation downstream of the engineered reach. The accumulation of sediment results in increased flood risk.

The afforestation of upland areas in the UK has been the largest rural land use change this century. As a consequence of afforestation the bed load yields of upland catchments have been shown to increase substantially. The upland catchment bed load is transported downstream, through the transfer zone to the lowland reaches where it may enter storage in barforms, cause flow diversion and cause channel instability. This study investigates the Afon Trannon, a river in mid-Wales whose upland catchment was afforested between 1948 and 1978 and whose lowland channel is currently unstable. Historical rates of channel change in the lowland channel have been quantified using aerial photogrammetry in ERDAS Imagine GIS. Channel instability is shown to increase significantly between 1963 and 1976, some 15 years after upland catchment afforestation. However, upland catchment bed load yields are shown to be of low magnitude (up to an estimated maximum of6.35 t km-2 yr") and incapable of producing the high medium-term lowland channel change rates observed (up to 1.88 m yr" between 1963 and 1976). Contemporary channel DTMs constructed from field survey data have allowed the construction of a contemporary lowland channel sediment budget. Local inputs of bed load from composite bank erosion are shown to dominate in the budget and reaches of maximum instability are shown to correspond with the location of these composite banks. Additionally. flood magnitude and frequency are shown to have increased since 1988 from a maximum stage of 1.50 m between 1969 and 1988 to a maximum stage of2.23 m between 1989 and 2000. A conceptual model is presented in which the medium-term instability of the lowland Afon Trannon is suggested to be triggered by local lowland bed aggradation as a result of elevated upland catchment bed load yields and a risk assessment diagram provides advice to river engineers and fluvial geomorphologists interested in assessing the potential stability of lowland rivers whose upland catchments have been afforested.

Healthy riparian vegetation has a positive impact on the adjacent river. Unfortunately, riparian vegetation is often threatened by human impacts such as dam construction and clearing. To gain the knowledge underlying the effects of such impacts and to aid riparian rehabilitation, the objective of this thesis was: to determine riparian vegetation association with, and response to, variation in fluvial geomorphology over several scales and consequently to fluvial disturbance. Only woody riparian plant species were considered. Flood disturbance was the unifying theme of this thesis. Linked to this theme and arising from the main objective was the supposition that plant interactions with the abiotic environment, but not biotic interactions between species, control riparian species distribution because of frequent fluvial disturbances. Woody riparian vegetation and riverine environmental variables were recorded along the upper Murrumbidgee River at three spatial scales based on a geomorphic hierarchy for Chapter 2. Multivariate analysis was used to group species and to associate environmental variables with vegetation at the three spatial scales. Observations at the two larger scales, of river segment (site) and riparian reach (transect), identified a river-longitudinal speciescomposition gradient associated with geology, river width and stream channel slope. Observations at the smallest scale of geomorphic units (plot) identified a lateral riparian gradient and also the longitudinal gradient; these gradients were associated with geomorphic variation, land use, plot elevation and also river longitudinal variables. Using the same data set, but varying the spatial scale of analysis caused the species composition pattern to change between scales. Increase in scale of observation, that is from geomorphic unit to reach and segment scales, resulted in disproportionate importance of rarer species and decreased importance of some key riparian species at the larger scales. It would appear that in this instance the geomorphic unit scale best described patches of different species composition because this scale had high spatial resolution and was also able to identify multiple gradients of environmental variation. It was recommended that riparian sampling take place at scales that represent dominant gradients in the riparian zone. These gradients are represented by geomorphic scales, indicating the appropriateness of using geomorphic based scales for observation of riparian vegetation. Chapter 3 considered whether there is a geomorphic template upon which riparian vegetation is patterned and whether it is associated with process variables, such as flooding and soil type. This question was investigated at different spatial scales in three ways: i) by an experiment to determine whether soil nutrient condition affects plant growth; ii) by graphical analysis of trends between geomorphic units, species and process variables; and iii) by analysis of vegetation distribution data. The smallest scale (meso) found experimental differences in plant growth because of soil type. Plants growing in sand had the lowest performance, with an average plant Relative Growth Rate (RGR) of 0.01, compared to plants growing in soils with small amounts of silt or clay particles, with an average plant RGR of 0.04. This pattern was attributed to differences in nutrients. Clear relationships were demonstrated at the larger geomorphic unit scale between species distribution and process variables. For example, hydrology and substratum type were found to be associated with geomorphic units and species. The largest scale considered in Chapter 3 was the riparian reach scale. At this scale species were clearly grouped around reach type. Therefore, geomorphology was considered to be a template for riparian species distribution. Findings in this chapter suggested that geomorphic variables should be good predictors of riparian species distribution. This hypothesis was tested and supported in Chapter 6. The experiments reported in Chapter 4 aimed to determine whether inundation depth and duration affected plant performance and survival for five common riparian zone species. Riparian seedling patterns in the field were also compared with experimental results to test whether species performance was reflected by field distribution. The experiments that were conducted included an inundation period and depth experiment, and a survival period test whilst under complete inundation. Biomass and height relative growth rates were determined, and the results were analysed using factorial Analysis of Variance. Obligate riparian species (Callistemon sieberi, Casuarina Cunninghamiana, Leptospermum obovatum) were found to be tolerant of inundation duration and depth, to the point where inundation provided a growth subsidy. On the other hand, non-obligate riparian species (Acacia dealbata, Kunzea ericoides) were either just tolerant of inundation or showed a negative growth response. For instance, C. sieberi demonstrated an average height RGR of 0.04 after complete inundation and 0.007 when not inundated, while A. dealbata had an average height RGR of 0.001 after complete inundation and 0.01 when not inundated. These experimental findings were found to closely reflect both seedling and adult plant distribution in the field such that inundation tolerant species were found close to the river and intolerant species further away. Thus, the conclusion was drawn that riparian species establishment and distribution is affected by inundation and that change to the flood regime could have serious impacts on riparian zone plant composition. The other aim of this chapter was to determine whether optimum germination temperatures were associated with flood or rainfall. Growth chamber germination trials were conducted at air temperatures of 15�C, 20�C and 25�C to determine the 'best' germination temperature. These germination patterns at different temperatures were then related to annual variation in field temperature, flooding period and rainfall. No evidence was found to suggest a relationship between ideal germination temperature and flood season, rather it was suggested that germination was patchy through time and may simply reflect recent rainfall. Investigations that were reported in Chapter 5 aimed to elucidate relationships between species and flow velocity variables. Two experiments were conducted: i) a flume experiment to determine the effect of flow velocity on plant growth; and ii) an experiment to observe the response of plants to damage (imitating flood damage) and inundation. Field observations of species distribution and flow velocity related variables were also conducted to put the flume results into a real-world context. Treatments for the flume experiment were fast flow velocity (0.74 m s-1), slow velocity (0.22 m s-1) and no velocity (control) but still inundated. All treatments were flooded completely for four days. Subsequent biomass and height relative growth rates were determined, and the results were analysed using factorial Analysis of Variance. Results were unexpected, given that obligate species exposed to the fastest velocity had the highest growth rate with an average height RGR of 0.046, compared to plants in still water, which grew the least with an average height RGR of 0.013. It was hypothesised that this response was because relatively greater carbon dioxide and oxygen levels were available in the moving water compared to the still water. With regard to shoot damage, the species that were nonobligate riparian species lost more leaves from velocity treatment than the obligate riparian species. The cut and flood experiment found growth of the obligate species (Casuarina cunninghamiana) to be greater after cutting than the non-obligate species. Flooding was not found to have an effect in the cut and flood experiment, probably because the period to sampling after flood treatment was longer (4 weeks) than other flooding experiments (3 weeks). Field observations were found to support the experimental findings, with a gradient of species across the riparian zone that reflected potential flood velocities. Therefore, velocity is one of a suite of riparian hydrological factors that are partially responsible for the gradient of species across the riparian zone. Potentially the absence of flooding could result in a homogeneous mix of species, rather than a gradient, except on the very edge of the river. The study that was reported in Chapter 6 investigated a technique for predicting riparian vegetation distribution. One of the aims of this investigation was to address a current riparian rehabilitation shortfall, which was how to objectively select species to plant for rehabilitation. Field data were collected from three confined river valleys in south-eastern New South Wales. Using data on plant species occurrence and site and plot measures of soils, hydrology and climate, an AUSRIVAS-style statistical model, based on cluster and discriminant analysis, was developed to predict the probability of species occurrence. The prediction accuracy was 85 % when tested with a separate set of plots not used in model construction. Problems were encountered with the prediction of rarer species, but if the probability of selection was varied according to the frequency of species occurrence then rarer species would be predicted more often. Various models were tested for accuracy including three rivers combined at the geomorphic unit (plot) scale and riparian reach (transect) scale in addition to a Murrumbidgee River plot scale model. Surprisingly, the predictive accuracy of the all rivers and single river models were approximately the same. However, the difference between the large scale and small scale models pointed to the importance of including small scale flood-related parameters to predict riparian vegetation. When these riparian predictions were compared to predictive outcomes from a hill slope model, which was assumed to be affected by fewer disturbances (i.e. flooding), predictive accuracies were not very different. Overall though, predictive accuracy for riparian vegetation was high, but not good enough to support the supposition that riparian vegetation is abiotically controlled because of frequent flood disturbance. Nevertheless, geomorphology and consequently flood effects are still important for the determination of the riparian community composition. Overall, riparian vegetation was found to be closely linked to its environment (evidenced in Chapters 2, 3, 4, 5) in a predictable manner (Chapter 6). Species pattern relied on flood disturbance affecting species distribution. Some riparian species were found to be highly tolerant of flooding and gained a growth advantage after flooding (Chapters 4 and 5). Therefore, flood tolerance was important for the formation of a species gradient across the riparian zone. These species tolerances and growth requirements reflect riparian geomorphic pattern (Chapter 3), which was suggested to form a template on which riparian vegetation is structured.

All living things mostly the humans, as builders of civilizations, have always been in intrinsic bonds with water. This interaction between water (oceans, seas, lakes, rivers etc.) and settlements has existed since ancient civilizations. Among water resources, &lsquo
flowing waters&rsquo
such as rivers, streams, creeks, etc. have a prominent role as they are the lifeblood of most cities in terms of providing transportation, security, energy, irrigation, commerce, and recreation. By the late 19th century, developments of terrestrial transportation modes diminished the magnetism of rivers and riverfronts, and growing industries led to the deterioration of rivers. Owing to these reasons, along with many others, they turned into sewage channels, were covered up, and became water scopes detached from the urban life. Particularly since the 1970s, with more attention given to sustainability of resources, a greater awareness has grown of the vital role of urban rivers as a resource for humans and a lifeline for cities. After being neglected for decades, urban rivers have started to be rehabilitated to solve the related problems. The new approach to urban river rehabilitation beyond classical practices that aim at recovering the physical conditions of rivers has come to the fore to address the problems comprehensively. Instead of independent and one-dimensional practices, the urban rivers have become to be seen as a vital part of urban water system and of the city itself. While rehabilitating urban rivers, recovering river health can be ensured provided that the entire urban water ecosystem is taken into consideration. The ecocity approach is one of the major new approaches that geared toward achieving a healthy city, and sustainability of water system is the significant goal within this approach. In this regard, the thesis first asserts that the ecocity criteria are likely to give way to a more sustainable future for urban rivers. Besides being a part of the ecosystem, urban rivers have transformed together with the surrounding built environment throughout the history of cities. Significant focal elements of the urban pattern, urban rivers should be dealt with other urban focal points, with the introduced concept of river-city integration, which is proposed as the second assertion of the thesis. In this respect, the study attempts to investigate urban rivers and their rehabilitation in relation with both the ecocity approach, and the river-city integration concept. The research methodology in the present study involves comparative anaysis of best practices and case study analysis. Porsuk River and the city of Eskisehir, which the river passes through, were selected as a case for empirical study. Criteria sets that determined within the frames of ecocity and river-city integration, and the testing of the criteria in the case area offers an opportunity to contribute to literature of river and city coexistence.

Researchers recognize the need to better understand the factors influencing indigenous land use in order to design sustainable tropical forest management programs. A key relationship that has been long overlooked in peasant societies is the one between communal labor access through social networks and land acquisition/accumulation. This study examines land distribution and labor patterns in traditional agriculture of a lowland and a upland community on the Maranon River near Iquitos, Peru. Data were gathered through household interviews (n=76) and field visits (n=396) between June and November 2001. Results reveal marked variations in access to land and communal labor between and within communities. Household age, initial land wealth and initial inputs of labor are crucial in explaining land and labor inequalities within villages. This research contributes to a better understanding of the factors that give rise to local heterogeneity in wealth holdings and livelihood strategies, necessary tools to promote conservation throughout the region and beyond.

Extensive drainage of UK peatlands has been associated with dehydration of the peat, an increase in water colour and a loss of carbon storage. Water colour has been found to be proportional to the concentration of fluvial dissolved organic carbon (DOC) (McKnight et al. 1985). It has been considered that the blocking of drainage channels represents a means of peat restoration and a way of reducing DOC losses to surface waters. This study aimed to assess the effectiveness of drain blocking at both an individual drain scale and at a larger catchment scale (up to 1km2). The effect of external parameters become more pronounced as the DOC record is examined at larger scales. The catchment is an open system and water chemistry will be influenced by mixing with water from other sources. Also it is likely that at some point the drains will cut across slope leading to the flow of any highly coloured water down slope, bypassing the blockages, and entering the surface waters downstream. Degradation of DOC will occur naturally downstream due to the effects of light and microbial activity. There is, consequently, a need to examine the wider effects of drain blocking at a catchment scale to ensure that what is observed for one drain transfers to the whole catchment. A series of blocked and unblocked catchments were studied in Upper Teesdale, Northern England. A detailed sampling programme of stream water, soil water and run off was undertaken in which a series of drains were studied in the 12 months prior to and post blocking. Water table depth, flow and weather parameters were also monitored. This study could not find a significant decline in DOC concentration at zero or first order scale post blocking; however a small yet significant decline of 2.5% in DOC concentration relative to the control catchment was recorded at the first order scale. A decrease in DOC concentration is recorded as water flows from the zero to the first order in the same catchment. The study found that the effects of DOC degradation in the catchments were very small and that DOC degradation could not solely explain the decrease in DOC concentration seen from zero to first order drains indicating the importance of dilution effects in the catchments. The blocking of peat drains does significantly decrease the export of DOC which is largely achieved by decreasing water yield. The size of the DOC export reduction caused by drain blocking is seen to decrease as scale increases providing evidence for the existence of bypass flow around the zero order drain blockages. Blocking was found to have little impact on the level of the catchment water table. This can be explained by the peat bog being naturally very wet before intervention such that when blocking did occur the soil had little capacity to take in additional water. Water yield, however, is seen to decrease post blocking indicating that water and potentially DOC is being lost from the system. Principle component analysis and event analysis were performed on the hydrological and chemical data in order to trace and define this missing component of the water balance yet the analysis found that the water chemistry in the study catchment can be defined by a relatively simple mixing trend. As such this missing water remains undefined. The presence of bypass flow and water mixing will reduce the efficiency of any drain blocking and have wider implications for upland management and its practitioners.

Although the impacts of changing land use on the magnitude and timing of erosion in lowland catchments are well documented, much less is known about the transfer dynamics of fine sediment through the upland hydrological networks. Using a novel distributed monitoring approach, this thesis examines the magnitude, timing and physical characteristics of fluvial fine sediment in two adjacent upland rivers in North Yorkshire (UK). Annual suspended sediment yield (SSY) estimates range from 33.92 t km-2 in the 131 km2 Upper Derwent catchment to 57.91 t km-2 in the 96 km2 River Esk catchment. Infrequent events were found to be of greatest importance, transferring up to 38% of the annual load in under two days. Simple annual and seasonal rating curves were constructed and are effective in predicting SSC with relative errors of less than 15%. Analysis of within-storm fine sediment dynamics indicated the dominance of sources proximal to the channel in the Esk catchment, whereas sediment sources in the Upper Derwent were more variable. Distributed time-integrated fine sediment sampling identified high SSYs in the headwaters of the Upper Derwent whereas in the headwaters of the Esk the minimum SSY was found with tributaries draining the central valley having maximum SSYs. Analysis of the absolute particle size observed significant downstream fining in both catchments and strong positive relationships between flow and particle size of the transported sediment. The data collected are also applied to four real-world scenarios to demonstrate the effectiveness of this approach. This research has enhanced our understanding of fine sediment delivery to upland channels through the assessment of the fine sediment dynamics at a range of temporal and spatial scales rarely studied in these environments.

River channel planform change in upland gravel-bed rivers has consequences for riparian land use, river habitats and flood hazards. Channel planform is predominantly determined by the balance between sediment supply and prevailing discharge regime which is governed by climate and land use, and anthropogenic channel modification. While the nature of channel response to individual factors is in some cases well documented, the complex interaction of theses variables and their relative significance requires further evaluation. This study assesses the nature and extent of historic (1856-1991) channel planform change in the upland catchment of the River Wear, Northern England. A nested research strategy is adopted consisting of catchment wide and reach-scale evaluations of channel planform change using archival maps and aerial photographs. The cause of channel changes is considered with reference to hydrological records (1800-present), catchment land use (metal mining) and accounts of river channel modification (gravel extraction). Comparative historic (reach-scale) and contemporary (trunk channel) data is provided from the upper reaches of the River Tees in Teesdale, Northern England. In the mid nineteenth century a pulse of sedimentation migrated through the upper Wear catchment resulting in the development of eight major sedimentation zones with channel braiding separated by confined single thread reaches. Increased sedimentation was related to a combination of high magnitude floods during the nineteenth century and enhanced sediment supply from extensive metal mining in tributary streams. A decline in flood frequency and magnitude coupled with the cessation of metal mining during the early twentieth century, led to a reduction of sediment supply and lateral channel instability in the catchment. This promoted gravel bar stabilisation through vegetation colonisation, reducing average channel width by 56%. In the sedimentation zones, gravel bar extent declined by up to 87% and this was accompanied by a change to a single thread planform. Gravel extraction operations during the mid-twentieth century lead to local instability and delayed the decline in gravel bar area. In contrast the contemporary channel of the upper Tees is still characterised by localised channel division, around both active gravel bars and vegetated islands. Differences between the two catchments demonstrate the importance of catchment specific controls such as bedrock control and anthropogenic channel interference. A large flood on 30 July 2002 provided significant insight into the mechanism of channel planform change. Substantial increases in gravel bar extents were recorded together with localised changes in flow routing. While local controls such as gravel extraction are significant over decadal time scales, catchment scale controls, primarily changes in the frequency of large floods; determine channel planform over centennial timescales. In order to discriminate ― between local and catchment controls, catchment wide assessments are required.

An understanding of runoff generation is a requirement for efficient erosion control and land management practices. This research is designed to investigate the processes by which runoff occurs on a Whatcom soil at an upland site in the Lower Fraser Valley. The objectives of this study are to summarize water erosion measurements, to determine soil hydraulic properties, to predict infiltration for typical rainstorms and to determine the mechanism of runoff generation. Rill, interrill and rainsplash measurements, and previous erosion measurements made at the study site are used to qualitatively assess the magnitude of water erosion. Soil loss is dominated by rill erosion and erosion rates are greatest from November to January. Runoff coefficients are relatively low (<26%), but erosion rates are anticipated to be in excess of 35-45 t ha⁻¹yr⁻¹. Soil hydraulic properties are measured using a low tension absorption technique described by Clothier and White (1981). The sorptivity tube device provides a simple method for obtaining S, λ* and K₋₂ Measured values of i and x* depend on t¹′² as expected from the constant-concentration absorption theory. Soil hydraulic variables and constant-concentration absorption theory are used to determine the soil-water diffusivity characteristics. Measured D(θ) functions for the field varied widely in a and b, especially for the lower horizons. The Van Genuchten (1980) θ(h) expression provides a good fit to the water retention data. D(θ) functions predicted from the soil-water retention curves and the conductivity at satiation are at least 1-2 orders of magnitude greater than the measured functions. Hysteresis effects may account for a 1 order of magnitude increase in D(θ), but the predictions are poor without matching at D(θ₅). The measured hydraulic properties are used to predict infiltration, runoff and drainage. Constant-flux infiltration theory is used to model soil moisture profiles for various rainfall events. High field moisture contents necessitate the inclusion of gravity effects during infiltration. Rainfall, runoff and soil loss measurements at the Mahal farm indicate that rainfall intensities <10 mm h⁻¹ cause considerable runoff and erosion. For rainfall intensities known to cause runoff and erosion, runoff is not predicted for most Ap horizon cores. Infiltration may be restricted at some sites by the lower horizon but runoff is not predicted at many sites. To evaluated soil moisture conditions between rainfall events, drainage is estimated from a unit gradient model. A rapid decrease in θ between rainfall events predicted by the unit gradient model, but θ measured at the Mahal farm suggests limited drainage between rainfall events. Rainfall, runoff and soil loss measurements suggest that factors other than those measured are contributing to the runoff observed in the field. Compaction, surface sealing and subsurface seepage may be factors influencing runoff and moisture conditions in the field. The high moisture contents observed in the field suggest the water table is perching on a layer of lower conductivity which in consistent with Dunne runoff. However, the measured infiltrabilities suggest Hortonian runoff and the resultes of the thesis are not conclusive with respect to the mechanism of runoff generation.
Land and Food Systems, Faculty of
Graduate

Acid Rain, or more correctly Acid Deposition, has been responsible for widespread damage to forests and to aquatic ecosystems, causing ecological simplification, the loss of acid-sensitive species and a reduction in biodiversity. Although major international agreements have succeeded in reducing acid deposition in Europe and North America, overall global emissions of acidifying pollutants continues to increase. Even in regions where the emissions have fallen substantially, biological recovery of many waters has been slower and more uneven than chemical recovery. In Scotland, the Galloway hills of the South West have been identified as showing particularly noteworthy discrepancies between predicted and observed recovery from acidification. Two main factors have been used to explain this: geology (specifically granitic bedrocks that have reduced buffering) and land-use (specifically coniferous afforestation that is widely associated with high levels of acidification impact).

Six rivers within the upper Mumbidgee catchment were sampled for larval and juvenile fish. The rivers represented both regulated and unregulated flow regimes and varied widely in size. There was wide variation in the larval fish communities supported by each river, both in terms of the species diversity and total abundance of fish sampled. The highly regulated reach of the Mumbidgee River sampled during this study had the highest numbers of native species and native individuals of any river sampled. In the two rivers selected for further study, the Murmmbidgee and Goodradigbee, there was a high level of inter-annual consistency in the species composition within the reaches sampled, despite considerable change in the temperature and flow regimes of both rivers. This indicates that at least some spawning of those species sampled may occur each year, regardless of environmental conditions. Estimates of the relative abundance of each species sampled changed markedly between years, and it is argued, on the basis of growth information contained in the otoliths, that differential survival of larvae and juveniles was largely responsible for this shift in relative abundance. Otolith microstructure provided information on the date of spawning and early growth patterns of all species sampled in the upper Mumumbidgee catchment. In addition to determining the age and thus 'birth-date' of an individual, the effect of a particular event or series of events has on growth, and subsequent survival, is permanently recorded in the otolith microstructure. This enables accurate back-calculation and correlation to management actions or natural events. No other research tool has this ability to retrospectively assess, on a daily basis, the impacts of management actions on condition and subsequent survival of fish larvae. Species sampled could be separated into three groups based on spawning requirements; those linked with flow, those linked with temperature and generalist species that appear to have river independent cues, such as photoperiod or moon phase. Patterns in growth rate during the early life history stages enabled quantification of the consequences of variation in environmental conditions on the survival and recruitment of various species. Growth was not always highly correlated with water temperature, in fact, for mountain galaxias, high temperatures appear to negatively affect larval condition and subsequent survival. Conversely, carp exhibited a strategy more consistent with common perceptions, with growth and survival increasing with increasing temperature. The study uncovered spawning and growth patterns that were unexpected. Age analysis of western carp gudgeon demonstrated that they had undertaken a mid-winter spawning, when the water temperature in the main channel was far lower than that at which spawning was previously recorded for this species. Redfin perch from the unregulated Goodradigbee River exhibited growth rates exceeding the published upper limits for this and other closely related species. This growth could not be correlated with either temperature or flow, indicating that there are additional factors that dominate growth rates of redfin perch in the Goodradigbee River. The proportion and abundance of native species alone is not necessarily indicative of a 'healthy' or pristine system; some native species may be positively affected by river regulation, at least as juveniles. Comparison of the current larval fish community with likely pre-European fish communities does provide an indication of change to the system. The results of this study suggest that larval fish growth rates can be strongly influenced by environmental conditions, thus providing a powerful tool for monitoring future change and the factors which cause it. This study has demonstrated the value of larval and juvenile fish age and growth information, derived from otolith microstructure techniques, for many aspects of river management. Current river management priorities for which these techniques provide unique information include the determination of environmental flow regimes and the control of undesirable exotic species such as carp.

Rates of river channel change in three contrasting Scottish upland environments have been studied within the context of Climatic fluctuation and landuse changes over the last 250 years. The object of the research was to assess the spatial and temporal variation in channel types, the main controls on channel pattern and the dominant modes of channel adjustment. This was undertaken in a hierarchic framework with sites being investigated at three spatial scales. At a macro-scale, the spatial and temporal variation in channel pattern was evaluated through a random sample of river channel segments for each study area, derived from the first and second editions of the 1:10,560 0.S. maps plus the 1:10,000 third edition. Each channel segment was classified within a map-based channel system typology, specifically constructed for upland Scotland. Measures of activity collected for each sample incorporated sinuosity, braiding and lateral shift indices. Flood histories were reconstructed for each study area on the basis of discharge records, long rainfall records and contemporary accounts, to assess if there was any evidence for climatic change, fluctuation or periodicities. Estimates of the recurrence interval of rainfall and runoff events of differing magnitude, frequency and duration were assessed. Data, mainly of a qualitative nature, were derived from contemporary sources and estate plans to evaluate whether any landuse changes could have changed the runoff regime and sediment mobility within each catchment. At a meso-scale, 7 to 9 channel segments (already identified as "active" within the macro-scale study) were subject to a more detailed process-response analysis, using sequential aerial photographs. Finally at a micro-scale, the unit stream powers at these sites were studied in relation to specific runoff rates thereby relating channel process to channel form. The strength of the controls on channel planform type varied in degree with the area studied. The glacial legacy, the positioning of local baselevels and sediment size were found to be dominant controls. In terms of channel dynamics, the position of the Channel planform in relation to process thresholds and the existence of a quasi-equilibrium condition were both very important. In terms of process-response, the following general observations hold true. An extreme event of high RI (>100 years) will have a major disruptive impact if there is room for expansion of the channel system and providing thresholds for sediment transport are exceeded. If these thresholds are high, the fact that the channel has not recently been disrupted may also be important. The modes of expansion across the active area depend on the type of channel involved. Different study areas have different types of Channel pattern present and thus a greater likelihood of certain types of planform adjustment. The role of more moderate events (10-50 years) varies principally with sediment size and Channel slope. Small-scale modification may take place where stream powers associated with more moderate events exceed competence thresholds. It was found that process rates were highly variable in both time and space and that present rates were not necessarily representative of the past 250 years. Even within this timespan, there have been periods of increased activity in response to increased discharges of moderate magnitude (eg. 1870s-1880s within the Dee study area) and random extreme magnitude floods (eg. between 1948-1956 in the Tweed study area). The impact of landuse change, especially in relation to sediment mobilisation (Dee and Spey study areas), and speed of runoff (Tweed study area) also appeared to be important.

New and renewable energy resources are important in view of reduction of greenhouse gasses causing climate change and in eliminating of dependence on foreign sources in energy respects. Within this context, hydraulic energy is evaluated as one of the prior energy resources that should be utilized. Turkey has 26 basins and Eastern Black Sea Basin is one of the most feasible basins with a lot of small hydroelectric power plants. In the other hand, there is not enough number of discharge gauging stations in the basin. For that reason, up to now generally area ratio method has been used to estimate the project discharges of small hydroelectric power plants. Objective of this study is to estimate &ldquo
the project discharge&rdquo
which is corresponding to 5 flow percentiles (5%, 10%, 15%, 20%, 25%) depending on topographical, meteorological, hydrologic and soil-land cover parameters through developing a multilinear statistical model for Iyidere Basin as a part of Eastern Black Sea Basin. Perimeter of the basin, the ratio of the basin perimeter to the main stream length of the same basin, the drainage frequency, the mean slope of basin, v the mean annual precipitation and the curve number are the parameters that have been analysed for the multilinear statistical model. Principal Component Analysis, Multiple Regression Analysis and Stepwise Regression Analysis have been run for the data sets. For the computed discharges validation has been done. As a result of validation, it has been seen that the stepwise regression gives much closer discharge values to the observed values than the multiple regression results.

Demand for energy is constantly growing both in the world and in Turkey. Sustainable development being an important concept, development of small hydro power projects has been popular in recent years. Eastern Black Sea Basin in Turkey has a lot of small hydro power potential because of high amount of precipitation and existence of steep slopes. Since the amount of river runoff is the only parameter that is variable in order to determine the power potential, it is vital to estimate the project discharge in ungauged basins accurately that have hydro power potential. Projects discharges of hydro-power plants in ungauged basins have been calculated using conventional methods up to now. This study aims to introduce a statistical model in linear and multi-variate form using the topographical and morphological parameters derived from GIS and hydro-meteorological variables to estimate the specific flow duration curves of potential small hydro-power locations for the selected study areas in Eastern Black Sea Region namely Solakli and Karadere basins. As well as developing an annual regression model using the annual values of hydro-meteorological parameters
seasonal regression model (spring season) has also been developed by including the mean seasonal (spring) air temperature variable instead of snow covered area (SCA) in addition to basin parameters. By studying the spring model, effect of different variables from the annual model were tested and discussed with some recommendations for the future studies.

River mouths are very active coastal regions. Continuous sediment supply by the river and the movement by wave action cause the shoreline to change in time and space. Modeling of shoreline changes is an essential step before the design of any coastal engineering project. This research aimed to develop a system of numerical models to present the shoreline changes around a river mouth. The system of numerical models has three components: 1) modeling of nearshore wave characteristics, 2) modeling of longshore sand transport rates using the results of the first component, 3) modeling of shoreline changes using the estimated sand transport rates. Thus, firstly, deep water wave characteristics including the annual wave rose affecting Manavgat River mouth have been obtained from the database of NATO TU-WAVES Project. Then REF/DIF1 and SWAN nearshore wave models have been used to find out nearshore wave conditions. Since the results obtained from REF/DIF1 wave model have been found to be more reasonable compared to SWAN&rsquo
s output, REF/DIF1 wave model has been used in preparing a time series nearshore reference wave file with three hours time interval. This reference file has been used to run GENESIS. Last step of the numerical shoreline change modelling of Manavgat River mouth was the calibration procedure in which the &ldquo
transport parameters&rdquo
k1 and k2 have been determined. As there is lack of measurements of shoreline positions that can be used in calibrating shoreline change model, k1 and k2 has been approximately found to be k1=0.516 and k2=0.9 by using an empirical sediment transport formula. As a future study, it is recommended that when the protection structure controlling the river mouth is finished, the measurements of shoreline position behind the structure should be used in verification of shoreline change model in order to get more accurate results.

River bridges get damaged or even collapse because of various reasons, such as development of adverse hydraulic conditions during severe floods, disastrous earthquakes, deficiencies in structural and geotechnical design, material deficiencies, or other unexpected external factors. Failure of service at vital lifelines, bridges, can lead to loss of several lives and properties, traffic disruption, and/or deficiencies in daily usage. Existing structures should be monitored periodically for decision-making and necessary protective works should be implemented to increase the safety. Types of items to be inspected would be categorized as structural, geotechnical, hydraulic, and status of materials. Requirement for periodic inspections and the ways of handling these activities are discussed within the framework of aforementioned aspects with special reference to the current situation of river bridges in Turkey and current practices in USA. An algorithm, composed of sets of checklists, is proposed. In such an algorithm, rank-based prioritization of events is identified. The evaluation and interpretation are displayed with the help of a few case studies, selected among several river bridges around Ankara.

Kü
ç
ü
k Menderes River Basin located in western Turkey has been facing continuous groundwater level decreases for the past 30 years. In dry periods, irrigation demand is completely met by pumping from groundwater system, which reduces water levels significantly. This provides enough storage to be recharged in wet seasons when streams are running. However, increased runoff in wet season are not utilized neither for irrigation nor for recharge and lost to the Aegean Sea without being infiltrated. Hence, surface artificial recharge methods can be useful to collect excess water in recharge basins, thus allowing infiltration to increase groundwater storage in wet seasons to be later utilized in dry seasons. A 2-D groundwater model is set up by using SEEP/W software. The material functions and parameters used in the model for saturated/ unsaturated conditions are taken from previous studies. Calibration was done to check the accuracy of input data and to control the validity of model. The amount of excess water that will be collected in recharge basins was estimated from flood frequency analysis. Concerning different probabilities, different scenarios were simulated to observe the increase in groundwater levels. Simulation results suggest that significant increase in groundwater storage could be achieved by applying artificial recharge methods. In addition to recharge basins, to reinforce the effect of artificial recharge, simulations were repeated with the addition of an underground dam at downstream side of the basin. Simulation results indicate that the increase in groundwater storage is not sufficient to warrant construction of the underground dam.

Proper bridge design is based on consideration of structural, hydraulic, and geotechnical conformities at an optimum level. The objective of this study is to develop an optimization-based methodology to select appropriate dimensions for components of a river bridge such that the aforementioned design aspects can be satisfied jointly. The structural and geotechnical design parts uses a statisticallybased technique, artificial neural network (ANN) models. Therefore, relevant data of many bridge projects were collected and analyzed from different aspects to put them into a matrix form. ANN architectures are used in the objective function of the optimization problem, which is modeled using Genetic Algorithms with penalty functions as constraint handling method. Bridge scouring reliability comprises one of the constraints, which is performed using Monte-Carlo Simulation technique. All these mechanisms are assembled in a software framework, named as AIROB. Finally, an application built on AIROB is presented to assess the outputs of the software by focusing on the evaluations of hydraulic &ndash
structure interactions.

In Turkey with increasing energy demand by industrialization and urbanization, hydropower seemed to be the most environmental friendly and sustainable solution for the problem. However, hydropower has also environmental effects especially when hydropower projects are numerous on a single river, and they use almost entire water in the river. Environmental flow as a new term became popular in media with increased density of small hydropower projects in Turkey. It is the required flow in the part of diversion for Run-off River type of hydropower plant in order to protect health of the river
in other words, to balance components of the river, including physico-chemical quality standards, surface and groundwater, geomorphological dynamics, social, economic, cultural and landscape values. In this study, an analysis utilizing hydrological (desktop) environmental flow assessment methods is prepared for Turkey, focusing on the Pazarsuyu Basin as a case study, and the results are compared with the applications done by the Governmental Institutions. Moreover, insufficient applications with regard to environmental flow assessment are given and reasons for public concerns are pointed out due to small hydropower development in Turkey.

Using a comparative spatial and temporal analysis on sediment cores from 8 lakes in the Mackenzie River Delta uplands region, NT, Canada, this study assessed how persistent organic pollutant (POP) deposition to lake sediments was affected by: (1) the presence of retrogressive thaw slumps on lake shores; and (2) changes occurring with increased autochthonous primary productivity. POPs examined included polychlorinated biphenyls (PCBs), penta- and hexachlorobenzenes (CBzs), and dichlorodiphenyltrichloroethane and metabolites (DDTs). Surface sediments of slump-affected lakes contained higher total organic carbon (TOC)-normalized POP concentrations than nearby reference lakes unaffected by thaw slumps. Inorganic sedimentation rates were positively related to contaminant concentrations, suggesting that the influx of siliciclastic material reducing organic carbon in slump-affected lake water indirectly results in higher concentrations of POPs on sedimentary organic matter. This explanation was corroborated by an inverse relationship between sedimentary POP concentrations and TOC content of the lake water. Deposition proxies of autochthonous carbon were not significantly correlated to POP fluxes of surface sediments, and historical profile fluctuations did not coincide with variation in POP deposition. Thus this study does not support the contention that algal-derived organic carbon increases the delivery of organic pollutants to sediments (the algal-scavenging hypothesis), as previously proposed for mercury. Higher POP concentrations observed in surface sediments of slump-affected lakes are best explained by simple solvent switching processes of hydrophobic contaminants onto a lower pool of available organic carbon when compared to neighbouring lakes unaffected by thaw slump development.

River terraces form prominent features of the valley floor morphology of many upland valleys in Scotland. Little is known, however, about valley floor landform development in many of these valleys. Previous studies have generally explained the terraces as the outwash products of meltwaters from the most recent cold periods. Detailed investigation of a major valley in the Scottish Highlands challenges, for at least one site, this well established concept and proposes the occurrence of at least three phases of Holocene terrace development. The correlation of terrace surfaces has traditionally been based upon the construction of height-range diagrams. An alternative approach to terrace correlation and dating is developed in this study using data from Glen Feshie, south-west Cairngorms. Terrace fragments are numerically classified and objectively grouped using quantitative soil-stratigraphic data. Principal Components Analysis and a hierarchical clustering technique numerically define five soil-stratigraphic units and place these on a relative time scale. Various methods of absolute dating control permit association of these units with five phases of terrace development. These are placed at 13,000, 10,000, 3,600, 1,000, 80, radiocarbon years BP. Comparison of palaeochannel networks preserved on the terrace surfaces suggests that these phases of terrace development have been associated with changes in channel pattern morphology. A unified approach to analysis of channel pattern morphology is developed and from this a new technique for palaeohydrological interpretation of gravel-bed streams. A segment density index is developed which allows total sinuosity to be predicted from just a part of the braided channel network. Application of these techniques to the Glen Feshie terraces demonstrates a trend for an overall decrease in discharge from the oldest terrace surfaces to the present day. Assessment of these landform changes within the context of known environmental fluctuations in the Cairngorms suggests that the early-mid Holocene was a period of relative landscape stability while the late Holocene was characterised by increasing instability. These changes may have been associated with the changes in river behaviour. However, spatial variation in the depth of the fill/bedrock interface may produce a discontinuous river response to changing environmental conditions.

This thesis analyzes the probable outcome of the fictitious failure of a dam under a set of pre-defined scenarios, within the framework of a case study, the case subject being the Cinarcik Dam located within Bursa Province of Turkey. The failure of the dam is not analyzed neither structural nor hydraulic-wise but is assumed to be triggered when certain critical criteria are exceeded. Hence, the analyses focus on the aftermath of the failure and strive to anticipate the level of inundation downstream of the dam itself. For the purpose of the analyses, the FLDWAV software developed by the National Weather Service of USA is used to spatially and temporally predict the flow profiles, water surface elevations and discharges occurring downstream of the Ç
inarcik Dam under the defined set of scenarios. Based on these analyses, indicative inundation maps and settlements under risk will be identified, and the thesis study will further address some available pre-event measures that may be taken in advance.

Numerical dam break analyses of Kirazlikö
prü
Dam are performed under various hydraulic scenarios. Kirazlikö
prü
Dam is located on the Gö
kirmak River near the city of Bartin. The objective of these analyses is to investigate adverse effects of such dam break failure on the regions downstream of the dam. The numerical model used in the simulations is FLDWAV, which is developed by the National Weather Service (NWS) in the United States. It appears that most adversely effected regions are those that are closest to the dam location. The results of these simulations can be used sufficiently to prepare emergency action plans in case of possible failures.

The Black Sea, with its oxic, suboxic and anoxic layers, provides a unique environment for studying how biological and geochemical processes affect the composition of particulate matter. The elemental composition of particles in the Black Sea is controlled by their origin and sources. Particles from rivers are dominated by aluminosilicate material that has compositions similar to the earth&rsquo
s crust. In general this material is relatively unreactive. Biological processes in the upper oxic and suboxic layers of the water column result in enrichments of elements which used as nutrients. Cu, Ba and Mo have been proposed as tracers for planktonic material and new production. Geochemical processes like manganese and iron recycling between oxidized and reduced forms, metal sulfide formation, and biogenic matter decomposition can have a large impact on the composition of particles in the suboxic and anoxic zones. The aim of this thesis was to study the composition of particles suspended in the water column of the Black Sea, in regional rivers draining into the Black Sea, and of particles deposited in these rivers and Black Sea sediments. The objectives were to determine the chemical composition and distribution of particles supplied by rivers and produced in the Black Sea, and compare with those particles buried in the sediments. The chemical distributions can help us to understand the biogeochemical processes taking place. The ultimate goal is to understand if there is a chemical signature that characterizes sediments deposited in anoxic basins that can be used to determine if ancient sedimentary rocks were deposited under such conditions. Water column filter samples were collected from the central western basin and along transects to the SW shelf regions during several research cruises of R/V Bilim and R/V Knorr in the Black Sea. Samples were taken by using both in situ large volume filtration systems and on deck vacuum filtration of discrete samples. River samples were collected by hand from the bank of four Turkish rivers and the Danube River. Sediment samples were obtained from 0 - 25 cm interval of a box core from the deep western basin. All samples were digested and analyzed by inductively coupled plasma - mass spectrometry and combination of atomic absorption (flame &
graphite furnace) instruments. The elements analyzed included Al, Ti, V, Cr, Mn, Fe, Ni, Co, Cu, Zn, Mo, Ag, Cd, Ba, Pb, and U. Great care was taken to avoid contamination and to obtain the highest level of precision and accuracy. The precision was typically about 5% for most elements. The accuracy, determined using standard reference materials, was also usually better than 5%. Another goal of this research was to determine the metal concentrations and best digestion methods using different types of filter materials. Blank filters were digested and analyzed and the analyses of various filter blanks are presented in the thesis. The analyses showed that the particulate matter data from Turkish Rivers were very similar to the composition of global average riverine particulate material and global average crust. The Danube River had elevated concentrations for some elements that were probably due to anthropogenic contamination. The Turkish river samples were closer to (but still higher than) the averages for the world&rsquo
s rivers but many elements in the Danube were much higher. These high values determined for major elements in the Danube samples strongly suggest considerable contamination of the Danube as compared to the Turkish Rivers. The Danube River samples were especially enriched in Pb, Zn, Ag, Cu, Cd, and Mn and slightly enriched with Cr and Ni. The first five elements, in particular, are well known indicators of pollution. The particulate matter in the water column of the Black Sea was influenced by lithogenic input from rivers, biological processes and geochemical processes. In order to examine the biogeochemical processes extensively, all the data were plotted as Metal/Al (Me/Al) ratios and compared with the ratios of the average crust and Turkish Rivers. Deviations were used to examine the anomalies due to biological and geochemical processes. In addition, the Al content of individual sample and the Me/Al ratio of crust or rivers were used to subtract the lithogenic component from the total composition. Enrichments due to biological processes were observed for Ba >
Fe >
Cr >
Mn >
Zn >
Ni >
Cu >
Mo >
V >
Co >
Cd >
U for the overall biogenic composition. Enrichments due to biology are most evident for Ba, Fe, Cr and Mn. This is a unique data set as there have been few previous analyses of biological enrichment for most of these elements. The results of particulate matter analyses showed that some elements including U, V, Cr, Ni, Cu, Co, Zn, Ba and Mo were enriched in the set of samples from the euphotic zone. Redox cycling in the suboxic zone was observed, as expected, for Mn and Fe, whose oxides play an important role in scavenging processes. The redox dependent processes in the suboxic &ndash
anoxic interface influence the vertical distribution of U, Ni, Co, Cu, Zn, Ba and possibly Mo, Cr and V. Elements influenced by sulfide formation in the anoxic layer are Fe, Cr, Ni, Co, Mo, and presumably Ag. The sediment data were also examined based on the same approaches. The elements Zn, Pb, U and Cd decreased with sediment depth over the top 5 cm suggesting that they were remobilized out of the sediments. In general the sediments from the Black Sea have Me/Al ratios very similar to local Turkish Rivers and average crust. There is no unique sediment signature (except possibly for Mo) indicating that these sediments were deposited under sulphidic conditions. This study does not support the hypothesis that the composition of ancient rocks can be used to characterize the environment of deposition.

The Montian Kartal Formation lies in the south-west of Ankara region and overlies the Upper Cretaceous Beyobasi Formation and is overlain by Thanetian Kirkkavak Formation conformably in the studied region (Kayabasi village, NW of town of Haymana). A 283 m stratigraphic section, which is mainly composed of an alternation siliciclastic and carbonate rocks has been measured in the Kartal Formation within the Haymana-Polatli basin. The aim of this study is to carry out the sedimentological and cyclostratigraphical analyses of the upper part of the Kartal Formation within Haymana-Polatli basin which represents a well developed cyclic pattern. In this study, detailed lithofacies analyses were performed and four different facies were recognized along the measured section: sandstones, limestones, mudrocks and conglomerates. Sedimentological analyses, such as modal, provenance, palaeocurrent, grain-size and grain parameters were also performed and their relation with the depositional environment and change in depositional conditions were discussed. Interpretations of the depositional environment revealed that the deposition occurred by low sinuosity rivers and waves. Additional environmental interpretations suggested that the sediments were deposited in shallow marine and/or coastal (beach) environments. High resolution cyclostratigraphy studies based on meter scale cyclic and rhytmic occurrences of lithofacies along the measured section were performed. The whole section, which is 283 m thick, was divided into large-scale hierarchy-cycles which comprise smaller-scale fining upward and deepening upward cyclic and rhythmic beds.

This study aims to determine the safe and sustainable development and management of groundwater resources in Ergene River Basin located in northwestern Turkey. A numerical groundwater model was developed for the Sandy Complex aquifer, which is the most productive and the most widespread aquifer in the basin. The finite difference model with 5900 cells was used to represent the steady and unsteady flow in the aquifer. The model was calibrated in two steps: a steady state calibration by using the observed groundwater levels of January 1970, followed by a transient calibration by using the observed groundwater levels for the period of January 1970 and December 2000. The resulting model was used to develop groundwater pumping scenarios in order to predict the changes in the aquifer system under a set of different pumpage conditions for a planning period of 30 years between January 2001 and December 2030. A total of eight pumping scenarios were developed under transient flow conditions for the planning period and the results were evaluated to determine the safe and sustainable yields of the aquifer. The results, presented in the form of a trade-off curve, demonstrate that the continuation of the present pumping rates exceeds both the safe and the sustainable yields of the aquifer system.

The purpose of this study is to investigate the geological and morphological features around ancient city of Zeugma. To achieve this, a geological map of Zeugma excavation site is prepared
an aerial photographic survey and morphological analyses are conducted on a broader area. Additionally, the biggest ancient quarry in the study area is investigated. In the close vicinity of Zeugma, four lithologies which are, from bottom to top, clayey limestone, thick bedded limestone, chalky limestone and cherty limestone are identified. A major fault with a vertical throw of 80 m is mapped in the area. Geological survey reveals that the excavation site is located within the chalky limestone and the rock tombs are carved within the thick bedded limestone. In the aerial photographic survey, Firat River is classified into 4 morphological classes which are river, island, flood plain and basement. The change among these classes is investigated between 1953 and 1992. The results reveal that there is no considerable variation in the position of the river channel and margins of flood plain within 39 years. The major change is observed in the islands that are built within the flood plain. Testing the elevation of Gaziantep and Firat formations boundary using the relief map, investigating the visibility of selected points in the area, predicting the source area for the water supply, and evaluating the nature of the ancient route, constitute the morphological analysis carried out in this study. However, these analyses are not studied in detail and should be considered as the first attempts for more detailed morphological analyses.

Waterhammer is an unsteady hydraulic problem which is commonly found in closed conduits of hydropower plants, water distribution networks and liquid pipeline systems. Due to either a malfunction of the system or inadequate operation conditions, pipeline may collapse or burst erratically resulting in substantial damages, and human losses in some cases. In this thesis, time dependent flow situations in the penstocks of small hydropower plants are investigated. A software, HAMMER, that utilizes method of characteristics for solving nonlinear differential equations of transient flow is used in the study. In two case studies, various operation conditions such as load rejection, load acceptance and instant load rejection are studied. The parameters and situations affecting pressure and turbine speed rises are investigated. Computed and available measured values are found to be very close. Also, differences between waterhammer responses of the Francis and Pelton turbines are revealed. Finally, specific protective measures are suggested to either diminish and/or avoid the harmful effects of waterhammer problems in small hydropower plants.

Floods can result in enormous causalities and huge economic losses in urban and rural regions. In recent years, while assessing the damage, risk analysis and assessment has become an important tool in addressing uncertainty in flood hazards. The lack of knowledge about the water extend, water depth, water velocity and potential damage in case of flood increase the vulnerability of the people to disasters in the flood region. Especially this information is valuable for city planners and decision makers. In case of new settlement area selection, correct decision can be taken by the help of this information. This type of information can be taken from hydraulic models as 1D or 2D. On the other hand, two dimensional (2D) hydraulic modeling becomes a need with increasing trends of very high speed computers and models instead of one dimensional (1D) ones. The ability of solving complex structures within few minutes enhances the use of 2D modeling with the integration of wave motion. In addressing the uncertainty, GIS becomes an important tool in risk assessment by integrating the flood depth, extend and vulnerability issues for definition of the quantitative risk. In this study, 1D and 2D hydraulic modeling is applied and combined with the quantitative vulnerability factors in Dalaman Plain-Turkey. Results show that the area is vulnerable to flood and high monetary damages can be seen in case a flood in the region.

Run-of-river type hydroelectrical power plants are the facilities that use only the available flow on the river without storing it to generate electrical energy. These kind of facilities are composed of structural components such as diversion weir, conveyance line, forebay, penstock and power house. In this thesis, a computer program called &ldquo
MiniHEPP Hydraulic Design&rdquo
is developed in order to perform the hydraulic design of run-of-river type hydropower plants. This program which runs under the Windows operating system, was developed in C# programming language. MiniHEPP Hydraulic Design is capable of performing hydraulic design of structural components of diversion weir with sidewise intake and overflow spillway, canal, forebay, and penstock. In addition, it can determine the optimum design discharge and penstock diameter of this type of hydropower plants.

This thesis aims to analyze the Black Sea environmental regime, which consists of three main parts. The first part of the study, after a general introduction to the environmental aspect of international politics, puts forward the regime formation in the field of environment and the development of global and regional environmental policy and law for the protection of coastal and marine environments. The second part firstly describes the peculiar characteristics and the environmental problems of the Black Sea. Secondly, it analyzes the disintegrative and integrative motives behind the establishment of the regime. Lastly, the legal, institutional and financial framework of the regime together with the role of international donors in the Region are put forward. The third part identifies the challenges affecting the functioning of the regime as well as the opportunities for the future of the Black Sea. The main concern of this study is to have an insight of the Black Sea environmental regime to see whether the regime has been functioning sustainably to enable the protection of the Black Sea and the recovery of its ecosystem.

Discharge estimations at certain cross sections of streams are very important for hydrologic studies especially for designs. In this study, it is aimed to determine regional mathematical equations that represent annual and monthly average discharges at desired locations using basin characteristics obtained with Geographical Information Systems (GIS) techniques and regression analysis. Study area covers three river basins, which are Gediz, Kü
ç
ü
k Menderes and Bü
yü
k Menderes. The data used are Digital Elevation Model (DEM), monthly average discharges observed at stream gauging stations and monthly total precipitation data from the precipitation observation stations in the study area. Stream networks are delineated from DEM using a GIS software. The basin parameters obtained from DEM are drainage area, total river length, main channel slope, main channel length and mean basin slope. Precipitation amount is also included in the analyses as the sixth parameter to improve the results. Using these parameters annual and monthly average discharge equations are determined and the best equation for each month is found based on the adjusted coefficient of determination values and stepwise regression analysis. Three models, each representing a different basin and a general model that represents the whole study area are developed. The verification of the models is made using the discharges at the additionally chosen stations that are not included in the model development. An interface that acquires the drainage area for a certain cross section and estimates the discharge according to the desired regression equation is written using arc objects and visual basic programming language. At the end, regression analysis results of the models are assessed and interpreted.

Snow indicates the potential stored water volume that is an important source of water supply, which has been the most valuable and indispensable natural resource throughout the history of the world. Euphrates and Tigris, having the biggest dams of Turkey, are the two largest trans-boundary rivers that originate in Turkey and pass throughout the water deficit nations Syria, Iran, Iraq and Saudi Arabia bringing life as well as water all their way. Snowmelt runoff originating from the mountains of Eastern Turkey accounts for 60 to 70 % of total annual discharge observed in Euphrates and Tigris. For an optimum operation of the dams, maximizing energy production, mitigation of floods and satisfying water rights, hydrological models which can both simulate and forecast the river discharges of Euphrates and Tigris are needed. In this study a hydrological model, snowmelt runoff model (SRM), is used in conjunction with remote sensing and geographic information systems to forecast the river discharges in the headwaters of Euphrates River, Upper Euphrates Basin. NOAA and MODIS satellite images were used to derive the snow covered area (SCA) information required by SRM. Linear reduction methodologies based on accumulated air temperature, with constant or varying gradient, were developed to get the continuous daily SCA values from the discrete daily satellite images. Temperature and precipitation forecasts were gathered from two different numerical weather prediction models, namely European Center for Medium Range Weather Forecasts (ECMWF) and Mesoscale Model Version 5 (MM5) from Turkish State Meteorological Services. These data sets provided t+24 hour forecasts of both temperature and precipitation. Temperature, precipitation and SCA information are fed into SRM. Discharge forecasts obtained from the model outputs are compared with the observed values. The overall performance of the model was seen as promising. Possible reasons of the mismatches between the forecasted and observed values are searched. Experiences gained throughout the study are summarized and recommendations on further forecast studies are mentioned.