Intact sagebrush communities in the Great Basin are rapidly disappearing due to invasion of non-native plants, large wildfires, and encroachment of pinyon pine and juniper woodlands. Land management options include the use of prescribed fire, grazing, herbicides and mechanical treatments to reduce the potential for wildfire and restore plant communities. Land managers in the region face a complex and interrelated set of ecological, economic, and social challenges to the implementation of these management practices. Effective restoration strategies require consideration of citizens in the region and their acceptance of management practices, as well as their trust in the agencies that implement them. This longitudinal panel study (2006-2010) examines the social acceptability of management options for rangeland restoration and public trust in agencies to carry out these options in three urban and three rural regions of the Great Basin. Most similar studies in this region have been largely place-based and cross-sectional, focusing on communities at one point in time. Results from this study can be used to evaluate the success of management programs, predict support for different treatments, determine the impact of agency outreach efforts, and identify important factors for building trust between communities and agencies across the region. The study uses data from a mail-back questionnaire sent to residents in 2006 and again in 2010. Overall, 698 respondents comprise the panel of interest. Results suggest landscape scale events such as wildfire, as well as agency management and outreach programs, had little influence on respondents' perceptions of agencies or management options over the study period. Several key findings have persisted throughout the study: (1) acceptance is high for the use of prescribed fire, grazing, felling, and mowing, but low for chaining and herbicide use, though there are (2) low levels of public trust and confidence in agencies to implement these management options, and (3) there are salient differences between the region's rural and urban residents with important implications for agency communication strategies. Most changes in response over the study period were subtle, though the direction and strength of these changes highlight noteworthy trends: (1) Great Basin residents are becoming more aware of key threats facing rangelands, (2) they seem more interested in having a role in making management decisions, and (3) they are slightly more positive about their interactions with agency personnel. Finally, findings suggest many residents have had little experience with agency outreach programs. Trust and confidence in management agencies are key factors in garnering support for restoration activities. While knowledge of management activities and confidence in managers' ability to competently implement them certainly play a role, findings strongly suggest sincerity factors (e.g., good communication or the perception that agencies share citizens' goals, thoughts, or values) have the greatest influence on acceptance of management practices in the Great Basin. Results suggest it would be beneficial for agencies to take a more active role in building trust with residents across the region. Differing levels of knowledge and interest, as well as different concerns, found among rural and urban residents highlight the need to tailor outreach strategies for use in specific communities. / Graduation date: 2012

The thesis focuses on the environmental sustainability ofwater projects. The concept is analysed from the theoreticaland the implementation viewpoints The evolution of the conceptof sustainable development is presented, with an in-depthdiscussion on the present status of the environmentalsustainability of water projects. Several case studies areanalysed on different important aspects of environmentalsustainability. These case studies include the analysis ofissues like the role of institutions, effectiveness of legalframeworks, participation of stakeholders, contributions ofwater development projects to regional development,consideration of environmental and social issues, and impactsof social and environmental movements. The impacts of the Ataturk dam, within the SoutheasternAnatolia (GAP) Project, Turkey, are analysed in terms ofplanning, policy making, institutional arrangements,infrastructural development, and human resources development.Its economic, social and environmental impacts during theconstruction phase and the first seven years of operation arereviewed. The role of large dams in poverty alleviation andsocio-economic development are analysed, especially in terms ofresettlement. The current global thinking on involuntaryresettlement is reviewed, as are the experiences onresettlement of the people affected by water projects. Anassessment of the participatory process that was formulated forthe resettlement of the people affected by the construction ofthe Birecik dam, GAP Project, Turkey, is presented. Institutional arrangements for integrated river basinmanagement in Latin America is analysed, with special emphasison the Brazilian and the Mexican experiences of watermanagement at the river basin level. Brazil and Mexico werechosen since they are by far the most advanced in this area,compared to all the other Latin American countries. It is concluded that economic, social and environmentaldimensions should be considered concurrently within the goalsof water development. Social considerations are essentialbecause poverty is both a cause and an effect of environmentaldegradation, and societies festering with poverty and socialtensions will not have the means, or inclination, to makesustainable development a priority issue. There are noblueprints for a transition to sustainability, but there arepolicy reforms that could reduce environmental degradation,income disparity and persistent poverty. The water sector isnot an exception to this conclusion. There is now considerable discussion on the operationalfeasibility of the sustainable development concept. It issuggested that sustainable development should be considered tobe a journey and not a destination. The world is nothomogeneous, and thus there cannot be one unique path tosustainable development that would be equally valid andapplicable for all countries of the world, and for alldevelopment sectors. Each country will have to base its waterdevelopment agendas depending on their own social, economic,cultural and environmental conditions, available managerial,technical and administrative capacities and societalexpectations and aspirations. For developing countries, as longas water development policies, programmes and projects cancontribute to socio-economic development, reduction in povertyand income disparity, and environmental conservation, they arewell on course in their long journey to sustainabledevelopment. Definitional debates as to what constitutessustainable water development are likely to beunproductive.

Deep troughs and ridges of the Arctic Basin are some of the least known features of the Earth's crust. Some of the ridges, eg. Chukchi and Nordwind, are connected directly to the continental shelves and are certainly submarine promontories of the latter. The character of the Lomonosov Ridge as a narrow slice of continental crust that separated from the Eurasian margin in the early Cenozoic (by opening of the Eurasian Basin), is not in doubt. Recent drilling (ACEX) and piston coring have confirmed this interpretation. However there are many other ridges and some of the troughs that are of uncertain origin. Seismic research in combination with potential field data over the East-Siberian margin, Podvodnikov and Makarov basins and the Mendeleev Ridge, presented here, provides a framework for understanding this enigmatic part of the Earth. The constrained models of the crust illustrate their structure. The crust beneath the East Siberian margin is up to 40 km thick; it thins to about 20 km towards to the Podvodnikov Basin. The models over the Arlis Gap, in the middle of the Podvodnikov Basin, and the Mendeleev Ridge have shown that the crust beneath both these features is anomalously thick (up to 28–32 km) and has a velocity structure that suggests the presence of highly attenuated continental crust. The crustal thickness over the Makarov Basin varies from 8 km to 15 km. Reflection profiles provide evidence of the character and thickness of the sedimentary cover (mostly Cenozoic and late Mesozoic), both on the ridges and beneath the troughs. Presented here is evidence that some of the ridges (eg. Marvin Spur) appear to be fragments of continental crust rifted off the Lomonosov Ridge (with a similar, unconformable Cenozoic cover); however, they gently plunge into and beneath troughs (eg. Makarov Basin). Reflection seismic data collected by the HOTRAX expedition in 2005 over the central part of the Lomonosov Ridge illustrate the sedimentary structure on the top of the Ridge and in an internal basin. The main sedimentary units can be interpreted by correlation with the ACEX results. The major fault separating the surrounding ridges from the internal basin appears to have a roll over anticline in the hanging wall, suggesting that the basin was created by a growth fault. The seismic lines provide evidence of gently folded basement beneath the Lomonosov Ridge with intra basement reflections are usually parallel to the upper surfaces; in combination with velocities (c. 4–5 km/s), these suggest the presence of old well-consolidated sediments.

It has been stressed within social sciences that risk management has focused too much on technical solutions and in order to decrease the risks also social factors have to be taken into account, namely the way people perceive risk. Risk perception is an important research field working on these issues. The aim of the study was in the light of the diverging views between the two paradigms to understand which of the psychometric or the cultural theory paradigm that can to a larger extent explain the flood risk perception of people living in the Tisza River basin. Furthermore the aim was to understand how the gap between experts’ and the public’s view on flood risk communication can be understood as well as how the risk communication could be improved. Data was collected through a survey and interviews. The results show that risk perception can partly be explained by either paradigm. To better understand people’s risk perception studies need to be more empirically based, not treat people’s perception as something too abstract and understand the interaction between individuals, society and the environment. The gap between the public’s and experts’ views is not as large as expected. In order to improve flood risk communication, decision makers need a better understanding of citizens’ perceptions and the motivation to include public perception in flood risk management need to be based on the view that the public could have an important input into risk management.

An expansive panel of well exposed (periglacial) strata of the Upper Kaza Group permitted a detailed study of the stratal architecture of proximal basin floor deposits in the Neoproterozoic Windermere turbidite system. Detailed stratigraphic and petrographic analyses identified six lithofacies: poorly-sorted, clast-rich mudstone (F1), thin-bedded siltstone and mudstone (F2), thick-bedded, massive sandstone (F3), medium-scale, cross-stratified sandstone (F4), mudstone-clast breccia (F5), and medium-bedded turbidites (F6). The spatial distribution of these facies identify five architectural elements: heterolithic feeder channel deposits (FA1), thin-bedded intralobe turbidites (FA2), terminal splay deposits (FA3), distributary channel deposits (FA4), and isolated scours (FA5). FA 1-4 are genetically related and form the basic building blocks of large-scale basin floor depositional lobes. FA 5, which is isolated to the stratigraphic top of the study area, is interpreted to have formed in a base-of-slope setting, and its superposition on FA 1-4 suggests the long-term progradation of the Windermere turbidite system.

Clearwells are large water reservoirs often used at the end of the water treatment process as chlorine contact chambers. Contact time required for microbe destruction is provided by residence time within the clearwell. The residence time distribution can be determined from tracer tests and is the one of the key factors in assessing the hydraulic behaviour and efficiency of these reservoirs. This work provides an evaluation of whether the two-dimensional, depth-averaged, finite element model, River2DMix can adequately simulate the flow pattern and residence time distribution in clearwells. One question in carrying out this modelling is whether or not the structural columns in the reservoir need to be included, as inclusion of the columns increases the computational effort required.<p> In this project, the residence time distribution predicted by River2DMix was compared to results of tracer tests in a scale model of the Calgary Glenmore water treatment plant northeast clearwell. Results from tracer tests in this clearwell were available. The clearwell has a serpentine baffle system and 122 square structural columns distributed throughout the flow. A comparison of the flow patterns in the hydraulic and computational models was also made. The hydraulic model tests were carried out with and without columns in the clearwell.<p> The 1:19 scale hydraulic model was developed on the basis of Froude number similarity and the maintenance of minimum Reynolds numbers in the flow through the serpentine system and the baffle wall at the entrance to the clearwell. Fluorescent tracer slug injection tests were used to measure the residence time distribution in the clearwell. Measurements of tracer concentration were taken at the clearwell outlet using a continuous flow-through fluorometer system. Flow visualization was also carried out using dye to identify and assess the dead zones in the flow. It was found that it was necessary to ensure the flow in the scale model was fully developed before starting the tracer tests, and determining the required flow development time to ensure steady state results from the tracer tests became an additional objective of the work. Tests were carried out at scale model flows of 0.85, 2.06, and 2.87 L/s to reproduce the 115, 280, and 390 ML/day flows seen in the prototype tracer tests.<p> Scale model results of the residence time distribution matched the prototype tracer test data well. However, approximately 10.5 hours was required for flow development at the lowest flow rate tested (0.85 L/s) before steady state conditions were reached and baffle factor results matched prototype values. At the intermediate flow, baffle factor results between the scale model and prototype matched well after only 1 h of flow development time, with improvements only in the Morril dispersion index towards prototype values with increased flow development time (at 5 h). Similar results were seen at the highest flow tested. For fully developed flow, there was little change in the baffle factor and dispersion index results in the scale model with varied flow rate.<p> With the addition of columns to the scale model, there was no significant change in the baffle factor compared to the case compared to without the columns, but up to a 13.9 % increase in dispersion index as compared to the tests in the scale model without columns for fully developed flow. Further, the residence time distribution results from the scale model tests without columns matched the entire residence time distribution found in the prototype tests. However, for the model with columns, the residence time distribution matched the prototype curve well at early times, but departed significantly from it at times later in the tests. It appears the major effect of the addition of columns within a model clearwell is to increase the dispersion index and increase the proportion of the clearwell which operates as a mixed reactor.<p> The results also showed there was good agreement between the physical model tests and River2DMix simulations of the scale model tests for both the flow pattern and residence time distributions. This indicates that a two-dimensional depth-averaged computer model such as River2DMix can provide representative simulation results in the case where the inlet flow is expected to be quickly mixed throughout the depth of flow in the clearwell.

Age-model derived sediment mass accumulation rates (MARs) are consistently higher than 230Th-normalized MARs in the Equatorial Pacific Ocean during the past 25 ka. The offset, being highest in the Panama Basin, suggests sediment redistribution in this region is prominent. I test the hypothesis that downslope transport of sediments from topographically highs that surround the Panama Basin is the cause of higher-than-expected xs230Th inventories in the deeper parts of the basin. There is little difference in xs230Th inventories between the highest and lowest reaches of the basin suggesting that the topographic highs did not serve as a source of xs230Th. A spatial analysis suggests that there may be an enhanced scavenging of xs230Th closest to the equator in productive waters. To examine whether lateral mixing of productive equatorial waters with adjacent waters delivers xs230Th to the Panama Basin, I measured dissolved 230Th in eight deep-water casts within the Guatemala, Panama, and Peru Basins along a meridional transect at ~86°W. Below 1000 m, the Panama Basin shows the highest deficit (~50%) of 230Th in deep waters assuming a reversible exchange of 230Th between dissolved and sinking particulate matter. Peru Basin waters have a larger range of dissolved 230Th concentrations (7.9-16.5 fg/kg) than that within Panama Basin waters (5.7-7.1 fg/kg). There is a progressive decrease, suggesting advection, in average dissolved deep-water (>1000 m) 230Th concentrations from the southernmost sites in the Peru Basin toward the Panama Basin. My calculations suggest that advected 230Th is between 15-30% of the total 230Th being produced within waters of the Panama Basin itself. In the Panama Basin, the averaged biogenic barium and opal MARs suggest that productivity was greater during the Holocene (0-13000 years) than that during the last glacial (13000-25000 years) suggesting higher productivity during the Holocene. Uauth, however, is higher in sediments deposited during the last glacial than in those deposited during the Holocene, suggesting that low bottom water oxygen contents rather than respiration of organic matter drives Uauth enrichment. This oxygen depletion during the last glacial suggests that bottom waters were enriched in respired carbon, which, in turn, could be a driver of lower glacial atmosphere pCO2 values.

An expansive panel of well exposed (periglacial) strata of the Upper Kaza Group permitted a detailed study of the stratal architecture of proximal basin floor deposits in the Neoproterozoic Windermere turbidite system. Detailed stratigraphic and petrographic analyses identified six lithofacies: poorly-sorted, clast-rich mudstone (F1), thin-bedded siltstone and mudstone (F2), thick-bedded, massive sandstone (F3), medium-scale, cross-stratified sandstone (F4), mudstone-clast breccia (F5), and medium-bedded turbidites (F6). The spatial distribution of these facies identify five architectural elements: heterolithic feeder channel deposits (FA1), thin-bedded intralobe turbidites (FA2), terminal splay deposits (FA3), distributary channel deposits (FA4), and isolated scours (FA5). FA 1-4 are genetically related and form the basic building blocks of large-scale basin floor depositional lobes. FA 5, which is isolated to the stratigraphic top of the study area, is interpreted to have formed in a base-of-slope setting, and its superposition on FA 1-4 suggests the long-term progradation of the Windermere turbidite system.

El estudio de los niveles y composición del material particulado atmosférico (PM) medido simultáneamente en diferentes ambientes a escala regional se llevó a cabo en la cuenca del Mediterráneo Occidental con el fin de entender las fuentes y patrones de transformación y transporte de aerosoles en esta zona. Para esto, la medida de niveles y caracterización química de PM10, PM2.5 y PM1 se llevó a cabo en tres estaciones de monitoreo: Montsec (MSC, fondo continental, 1570 msnm), Montseny (MSY, fondo regional, 720 msnm) y Barcelona (BCN, fondo urbano, 68 msnm). Además, se midieron niveles de número de partículas (N) y carbono negro (BC) en BCN. Durante el invierno, la frecuente estabilidad atmosférica induce el estancamiento de masas de aire produciendo importantes episodios de contaminación en BCN. Sin embargo, MSY y, más frecuentemente MSC, quedan aislados de la contaminación regional. En determinados escenarios, el desarrollo de la capa límite y las brisas resultan en el transporte de masas de aire contaminadas a zonas rurales, aumentando notablemente los niveles de PM en función de la altitud y la distancia a las zonas fuente. Durante el verano, la circulación de brisas favorece la dispersión, mezcla y envejecimiento de contaminantes a escala regional y la reducción de las diferencias entre BCN, MSY y MSC. Se midieron niveles similares de algunos componentes (materia orgánica, sulfato) a escala regional. Los niveles de materia mineral aumentan en verano por una resuspensión favorecida y una mayor frecuencia de intrusiones africanas, más significativamente en el MSC, dado su impacto en altura. La mayor contribución al PM10 en BCN se debe principalmente al tráfico (50% del PM10), resultante de las emisiones del tráfico primarias, nitrato y aerosoles secundarios envejecidos. La materia mineral se origina por resuspensión del polvo de carretera por vehículos pero también resuspensión por viento y obras. La contribución regional en BCN (25%) es principalmente materia mineral, nitrato y sulfato amónico. La variabilidad horaria de los diferentes parámetros de medida de aerosoles en BCN (N, BC, PM10, PM2.5 y PM1) está muy marcada por emisiones de tráfico y meteorología (especialmente brisas). Sin embargo, algunos parámetros no se rigen solamente por emisiones directas del tráfico, como PM2.5-10 (resuspensión) y N (emisiones de partículas ultrafinas y procesos de nucleación fotoquímica). La influencia de las emisiones del tráfico en los niveles de partículas finas en BCN se refleja en los niveles anuales de PM1, que aumentan de 2003 a 2007 relacionados con un aumento progresivo del tráfico y la flota diesel en BCN. Sin embargo se observó una tendencia decreciente en las fracciones gruesas en BCN y MSY, que se atribuye a la meteorología y a cambios en emisiones industriales. El estudio simultáneo de diferentes parámetros ha mostrado que el control de PM1 (modos de nucleación y acumulación) y/o BC (procesos de combustión), y PM10, (combustión y aerosoles generados mecánicamente) puede ser una estrategia mejor que la combinación de PM2.5 y PM10 como estándares de medida de calidad del aire. La medida en paralelo de aerosoles en fondos urbano, regional y continental ha sido una estrategia útil para entender la fenomenología de aerosoles en la cuenca del Mediterráneo Occidental. Las emisiones urbanas e industriales tienen un impacto considerable en los niveles y composición de PM en zonas rurales situadas a diferentes alturas, tanto en verano, con una importante recirculación y mezcla de masas de aire a escala regional, como en invierno, con transporte de contaminantes activado por brisas. El gran impacto de la contaminación urbana a escala regional demuestra la importancia de aplicar estrategias de reducción de emisiones de tráfico urbano, a fin de mejorar la calidad del aire no sólo a nivel local, sino también a escala regional. / A detailed study of atmospheric particulate matter (PM) levels and composition measured simultaneously in different environments at a regional scale was performed in the Western Mediterranean Basin in order to understand the sources, transformation and transport of tropospheric aerosols in this area. In this direction, the monitoring of PM10, PM2.5 and PM1 levels and chemical characterization was carried out at three monitoring stations: Montsec (MSC, continental background, 1570 m.a.s.l.), Montseny (MSY, regional background, 720 m.a.s.l.) and Barcelona (BCN, urban background, 68 m.a.s.l.). In addition, number concentration (N) and black carbon (BC) levels were monitored at BCN. During winter, the frequent anticyclonic atmospheric stability induces the stagnation of air masses that produce important pollution episodes at BCN. However, atmospheric decoupling leaves MSY and, more frequently MSC, isolated from regional pollution during several days. In specific scenarios, the growth of the boundary layer and development of mountain breezes, activated by solar radiation, result in the transport of polluted air masses accumulated in the valley to the rural sites, increasing markedly PM levels at a different rate depending on the altitude and distance to the source areas. During summer, intense breeze circulations and atmospheric mixing favour the dispersion, recirculation and ageing of pollutants at a regional scale, reducing the differences between the urban and the rural sites. Similar levels of some components (organic matter or sulphate) were measured at a regional scale. Mineral matter levels increase during the summer, because of a favoured dust resuspension and higher frequency of African dust outbreaks, more significantly at MSC given the impact of African dust at higher altitudes. The major contribution to PM10 in BCN was mainly related to road traffic (50% of PM10), resulting from primary traffic emissions, secondary nitrate and aged secondary aerosols. Anthropogenic dust may originate from road dust resuspension by vehicles, but also wind resuspension and construction/demolition works. The regional contribution at the urban site (25%) was mainly mineral dust, ammonium sulphate and nitrate. The hourly variability of aerosol measurement parameters (N, BC, PM10, PM2.5 and PM1) at BCN is very influenced by road traffic emissions and meteorology (especially breezes). However, some parameters are not only governed by traffic exhaust emissions, as PM2.5-10 (dust resuspension processes) and N (direct ultrafine particle emissions but also photochemical nucleation processes). The influence of road traffic emissions on the levels of fine PM at BCN is reflected in PM1 mean annual levels, showing an increasing trend from 2003 to 2007 and correlation with the progressive rise in road traffic flow and diesel fleet in BCN. However a decreasing trend was observed for the coarser fractions at BCN and MSY, attributed to meteorology and changes in industrial emissions. The simultaneous study of different parameters showed that the monitoring of PM1 (nucleation and accumulation modes) and/or BC (combustion processes), and PM10 (combustion and mechanically-generated aerosols) may be a better strategy than the combination of PM2.5 and PM10 measurements as air quality standards. The parallel monitoring of aerosols at urban, regional and continental backgrounds was a useful strategy in order to understand the phenomenology of aerosols in the WMB. Urban and industrial emissions have a considerable impact in PM levels and composition in rural areas at different altitudes, both in summer, with important atmospheric recirculation and mixing of air masses at a regional scale, and winter, with breeze-activated transport of stagnated urban pollutants. The high contribution of urban emissions and the transport of air masses at a regional scale demonstrate the importance of applying emission abatement strategies for urban road traffic, in order to improve air quality not only at a local, but also at a regional scale.

Clearwells are large water reservoirs often used at the end of the water treatment process as chlorine contact chambers. Contact time required for microbe destruction is provided by residence time within the clearwell. The residence time distribution can be determined from tracer tests and is the one of the key factors in assessing the hydraulic behaviour and efficiency of these reservoirs. This work provides an evaluation of whether the two-dimensional, depth-averaged, finite element model, River2DMix can adequately simulate the flow pattern and residence time distribution in clearwells. One question in carrying out this modelling is whether or not the structural columns in the reservoir need to be included, as inclusion of the columns increases the computational effort required.<p> In this project, the residence time distribution predicted by River2DMix was compared to results of tracer tests in a scale model of the Calgary Glenmore water treatment plant northeast clearwell. Results from tracer tests in this clearwell were available. The clearwell has a serpentine baffle system and 122 square structural columns distributed throughout the flow. A comparison of the flow patterns in the hydraulic and computational models was also made. The hydraulic model tests were carried out with and without columns in the clearwell.<p> The 1:19 scale hydraulic model was developed on the basis of Froude number similarity and the maintenance of minimum Reynolds numbers in the flow through the serpentine system and the baffle wall at the entrance to the clearwell. Fluorescent tracer slug injection tests were used to measure the residence time distribution in the clearwell. Measurements of tracer concentration were taken at the clearwell outlet using a continuous flow-through fluorometer system. Flow visualization was also carried out using dye to identify and assess the dead zones in the flow. It was found that it was necessary to ensure the flow in the scale model was fully developed before starting the tracer tests, and determining the required flow development time to ensure steady state results from the tracer tests became an additional objective of the work. Tests were carried out at scale model flows of 0.85, 2.06, and 2.87 L/s to reproduce the 115, 280, and 390 ML/day flows seen in the prototype tracer tests.<p> Scale model results of the residence time distribution matched the prototype tracer test data well. However, approximately 10.5 hours was required for flow development at the lowest flow rate tested (0.85 L/s) before steady state conditions were reached and baffle factor results matched prototype values. At the intermediate flow, baffle factor results between the scale model and prototype matched well after only 1 h of flow development time, with improvements only in the Morril dispersion index towards prototype values with increased flow development time (at 5 h). Similar results were seen at the highest flow tested. For fully developed flow, there was little change in the baffle factor and dispersion index results in the scale model with varied flow rate.<p> With the addition of columns to the scale model, there was no significant change in the baffle factor compared to the case compared to without the columns, but up to a 13.9 % increase in dispersion index as compared to the tests in the scale model without columns for fully developed flow. Further, the residence time distribution results from the scale model tests without columns matched the entire residence time distribution found in the prototype tests. However, for the model with columns, the residence time distribution matched the prototype curve well at early times, but departed significantly from it at times later in the tests. It appears the major effect of the addition of columns within a model clearwell is to increase the dispersion index and increase the proportion of the clearwell which operates as a mixed reactor.<p> The results also showed there was good agreement between the physical model tests and River2DMix simulations of the scale model tests for both the flow pattern and residence time distributions. This indicates that a two-dimensional depth-averaged computer model such as River2DMix can provide representative simulation results in the case where the inlet flow is expected to be quickly mixed throughout the depth of flow in the clearwell.