A perennial streamflow hydrograph, when measured at the outlet of a basin, continuously and without interruption, can be considered as an integral measure of hydrologic responses. Some of the theoretical and practical aspects of treating streamflow hydrographs as integral indicators of basin properties are addressed in this dissertation. This dissertation is divided into two parts. In the first part, a framework to identify and evaluate whether a streamflow variable is consistent and distinguishable in a given time scale and therefore can be considered as a streamflow index, is developed. The suggested framework is evaluated using as an example two streamflow variables that describe some aspects of the hydrograph shape. In the second part of the dissertation, the utilization of these streamflow indices in hydrologic model parameter estimation is demonstrated. It is assumed that streamflow indices that are evaluated on long streamflow records include large variability of climatic scenarios. Therefore, regardless of climate variability, the consistency and distinguishability are maintained the indices are more related to physical properties of a basin. Consequently, the problem of estimating model parameters that are related to basin properties can be approached by a comparison of indices between the observed and simulated streamflow. Three case studies are presented: the first demonstrates that using the streamflow index which describes the shape of the hydrograph in the parameter estimation processes improves consistency of prediction skill of the 5-parameter HYMOD model in the Leaf River, Mississippi. The second case study explores an important property of the shape descriptors as being relatively insensitive to errors in the data. Such property can be potentially used to identify key sources of uncertainty and to select model parameters that are less affected by data errors. In the final case study, the shape descriptors were used to derive the parameters of the gamma function as a model for the basin's Instantaneous Unit Hydrograph (IUH).

published_or_final_version / Civil Engineering / Master / Master of Philosophy

I studied the atmospheric jet streams of Jupiter and Saturn through numerical simulations. Jupiter and Saturn have approximately 30 and 15 jet streams, respectively, alternatively blowing eastward and westward at the cloud level. My studies are motivated by recent space probe observations of the giant planets, which are revealing vertical structures and time dependent behaviors of the atmospheric jets. Such new findings are important keys to understanding how the jets are driven and maintained. My first project tested the hypothesis that a large convective storm on Saturn observed in 1990 decelerated the equatorial jet. The equatorial jet's speed is reported to be ∼275 ms⁻¹ today, half of the speed measured by the Voyagers in 1980-81. It has been hypothesized that the large storm is responsible for causing the observed slowdown. Our result shows that the storm's effect is insufficient to cause a slowdown of the observed magnitude. The second project investigated the formation of Jovian jet streams, namely, whether Jupiter-like atmospheric jets emerge from self-organization of small initial vortices. Thunderstorms are observed on Jupiter and have been proposed to be the sources of small-scale vorticity. Our result shows that self-organization of initial small vortices leads to east-west jets under various Jupiter-like conditions. Third, I tested the stability of shallow atmospheric jets under Jovian conditions. Deep atmospheric jets have been shown to be stable on Jupiter; however, the possibility that those jets are shallow, with the point of zero-motion at perhaps ∼100-bar level, is not well explored and deserves a thorough examination.

Monitoring successful urban stream restorations can provide guidance for best practices for restoration design. My case study was located at Critter Creek, a tributary to the Grand River, in northeast Waterloo, Ontario, Canada, where due to high flow and tight meanders, six constructed offline ponds have become connected to the main stream and are now online ponds. This project aimed to evaluate how these online (formerly offline) ponds are affecting the restoration of the stream. The majority of research on this topic has concentrated on ponds specifically constructed for stormwater management or on urban restored streams without ponds. In many restoration plans, offline ponds are proposed to compensate for cut-fill balances and/or for habitat diversity. The relationship of these offline ponds to the function and ecology of the channel has not often been assessed. Benthic macroinvertebrates were used as indicators of restoration as a proxy for water quality. Using a Surber sampler, samples were collected in the reaches of the stream upstream of the inlet and downstream of the outlet of each pond. Comparative samples were taken from waterbodies that provided a restored stream without offline ponds and a reference stream. In the laboratory, all benthic macroinvertebrates were identified to the Family level. Ecology-based metrics (EPT, functional feeding groups, etc.) and an index (Hilsenhoff FBI) were used to characterize the assemblages. The Percent Model Affinity (PMA) Method was used to determine the impairment of the streams and Mann-Whitney tests were conducted to determine if differences existed between the samples taken close to the ponds and those not close to the ponds. Those tests were also conducted to determine differences between Critter Creek and the reference and other restored stream. PMA results from monitoring from previous years indicated that Critter Creek was an impaired stream, and this research shows that the stream is still impaired with PMA values less than 33.23% for 83 of 89 samples. Mann-Whitney tests showed that the location in Critter Creek, whether it be adjacent to an online pond or not, does not have an effect on the benthic assemblages. They also indicate that the composition of the benthic assemblages in Critter Creek has not reached the same stage as those in Laurel Creek, the reference stream, or Clair Creek, the other restored stream. While the habitat and functional requirements of organisms between all three streams is similar, the water quality present in Critter Creek is much lower than in the other two streams. Further monitoring could be completed to determine the trajectory of the benthic macroinvertebrate assemblages in this restoration. However, given that monitoring for the past 10 years has shown that the ecosystem integrity of Critter Creek is not improving, it is advised that action be taken now to improve the stream restoration. The concepts of urban ecology were addressed in this study and a wider-scope monitoring program could be completed to determine the impact of urbanization on the restoration of Critter Creek.

The North Mountain of the Annapolis Valley, NS, in eastern Canada, is a ~200 km basalt ridge drained by many small first or second order streams in independent catchments. The area is fairly uniform geologically, presenting an opportunity to compare streams of similar chemistry, slope and aspect, that vary in other respects, such as invertebrate community structure. In this thesis, I examine two macroinvertebrate functional groups to determine key factors influencing their abundance, composition and diversity across catchments. Chapters 2 and 3 are concerned with the predatory invertebrate guild in eight of the streams, in two groups separated by ~65 km. In Chapter 2, I assessed factors influencing composition of the predator guild using similarity matrices. Similarity in predator composition declined with distance, and streams that were more similar in disturbance (spates) were more similar in predator composition. Similarity within one family, Rhyacophilidae, was related to similarity in fish population. Chapter 3 reports the results of laboratory experiments involving two widespread species. Field data suggested an asymmetric interaction between Sweltsa onkos (Plecoptera: Chloroperlidae) and Rhyacophila vibox (Trichoptera: Rhyacophilidae); behavioural observations in artificial streams supported this. In the presence of R. vibox, S. onkos had higher mortality and injury rates, and grew less. The results of these chapters suggest that, although disturbance is important in shaping community structure, the results of interspecific interactions can be detected at large scales. S. onkos can only attain high numbers in streams where fish predation reduces the abundance of R. vibox. Chapter 4 examines biodiversity patterns in the macroinvertebrate detritivore guild in 25 streams encompassing ~80 km of the ridge. Using density and richness of the detritivore community, detrital resource quantity, and top predator abundance, I looked for evidence in support of several mechanisms that can lead to positive species-energy relationships. Patterns conformed to expectations of the ‘More Individuals Hypothesis’. It appears that taxonomic richness of the detritivore guild increases with detrital resource availability because more taxa can attain their minimum viable population size where more resources are available.

Downstream adjustment in stream channel morphology is examined in the context of stream channel confluences. Stream channel confluences represent areas of point specific increases in discharge, flow energy and potential erosion in a river system which will in turn affect the post-confluence downstream morphology. Analysis of 12 confluence junctions from southern Ontario streams, constituting 36 channel reaches in total, show an internally consistent hydraulic geometry relationship but with specific controls on channel morphology related to boundary conditions. Predictions of mainstem morphologies is possible using tributary attributes but reach specific channel confinement and material type add significant influence.

Tropical freshwater ecosystems are understudied and not well understood relative to temperate systems; however, they are becoming increasingly imperiled by escalating anthropogenic impacts. The aim of this thesis was to investigate how tropical freshwater macroinvertebrate communities changed both structurally and functionally over a pristine-rural-urban land-use gradient, in relation to different spatial and temporal scales, as well as to the availability of potential food sources. Fifteen streams in the Panama Canal Watershed were sampled during the dry and wet seasons of 2007 and 2008, for macroinvertebrate communities (benthic and leaf litter), environmental variables, and potential food sources. Along the land-use gradient, in both habitat types, taxon richness, diversity, and evenness all decreased significantly; whereas, abundance increased significantly. For the benthic macroinvertebrate community, unique variation was explained equally well by local (water chemistry and sediment type) and landscape (riparian vegetation and watershed land use) characteristics in the dry season, and landscape characteristics explained slightly more variation in the wet season. Leaf-litter macroinvertebrate community unique variation was better explained by local variables than by landscape variables in both seasons. In terms of potential food resources, fine detritus and inorganic material were the most common across all streams (increased quantities in urban streams) and seasons; whereas, the availability of diatoms and leaf material increased in the dry season. Using gut content analyses, we found that collectors (gatherers and filterers) were by far the most common functional feeding group, increasing in abundance along the land-use gradient. Predators, shredders, and scrapers were all most abundant in pristine streams and decreased along the land-use gradient. Finally, using seven community metrices, a potential biomonitoring tool was developed, the Neotropical Low-land Stream Multimetric Index (NLSMI), which distinguished well among the different levels of stream impairment. This study demonstrated that tropical communities were negatively affected by human land alteration, but that community responses depended on the habitat sampled, the influence of different spatial scales varied between the seasons, and the effect of food resources appeared to be complex. These aspects must be taken into consideration for management decisions and restoration strategies to be effective.

Problem determination is the identification of problems and performance issues that occur in an observed system and the discovery of solutions to resolve them. Top-k analysis is common task in problem determination in database management systems. It involves the identification of the set of most frequently occurring objects according to some criteria, such as the top-k most frequently used tables or most frequent queries, or the top-k queries with respect to CPU usage or amount of I/O. Effective problem determination requires sufficient monitoring and rapid analysis of the collected monitoring statistics. System monitoring often incurs a great deal of overhead and can interfere with the performance of the observed system. Processing vast amounts of data may require several passes through the analysis system and thus be very time consuming. In this thesis, we present our lightweight top-k analysis framework in which lightweight monitoring tools are used to continuously poll system statistics producing several continuous data streams which are then processed by stream mining techniques. The results produced by our tool are the “top-k” values for the observed statistics. This information can be valuable to an administrator in determining the source of a problem. We implement the framework as a prototype system called Tempo. Tempo uses IBM DB2’s snapshot API and a lightweight monitoring tool called DB2PD to generate the data streams. The system reports the top-k executed SQL statements and the top-k most frequently accessed tables in an on-line fashion. Several experiments are conducted to verify the feasibility and effectiveness of our approach. The experimental results show that our approach achieves low system overhead. / Thesis (Master, Computing) -- Queen's University, 2009-08-31 12:42:48.944

Downstream adjustment in stream channel morphology is examined in the context of stream channel confluences. Stream channel confluences represent areas of point specific increases in discharge, flow energy and potential erosion in a river system which will in turn affect the post-confluence downstream morphology. Analysis of 12 confluence junctions from southern Ontario streams, constituting 36 channel reaches in total, show an internally consistent hydraulic geometry relationship but with specific controls on channel morphology related to boundary conditions. Predictions of mainstem morphologies is possible using tributary attributes but reach specific channel confinement and material type add significant influence.

Tropical freshwater ecosystems are understudied and not well understood relative to temperate systems; however, they are becoming increasingly imperiled by escalating anthropogenic impacts. The aim of this thesis was to investigate how tropical freshwater macroinvertebrate communities changed both structurally and functionally over a pristine-rural-urban land-use gradient, in relation to different spatial and temporal scales, as well as to the availability of potential food sources. Fifteen streams in the Panama Canal Watershed were sampled during the dry and wet seasons of 2007 and 2008, for macroinvertebrate communities (benthic and leaf litter), environmental variables, and potential food sources. Along the land-use gradient, in both habitat types, taxon richness, diversity, and evenness all decreased significantly; whereas, abundance increased significantly. For the benthic macroinvertebrate community, unique variation was explained equally well by local (water chemistry and sediment type) and landscape (riparian vegetation and watershed land use) characteristics in the dry season, and landscape characteristics explained slightly more variation in the wet season. Leaf-litter macroinvertebrate community unique variation was better explained by local variables than by landscape variables in both seasons. In terms of potential food resources, fine detritus and inorganic material were the most common across all streams (increased quantities in urban streams) and seasons; whereas, the availability of diatoms and leaf material increased in the dry season. Using gut content analyses, we found that collectors (gatherers and filterers) were by far the most common functional feeding group, increasing in abundance along the land-use gradient. Predators, shredders, and scrapers were all most abundant in pristine streams and decreased along the land-use gradient. Finally, using seven community metrices, a potential biomonitoring tool was developed, the Neotropical Low-land Stream Multimetric Index (NLSMI), which distinguished well among the different levels of stream impairment. This study demonstrated that tropical communities were negatively affected by human land alteration, but that community responses depended on the habitat sampled, the influence of different spatial scales varied between the seasons, and the effect of food resources appeared to be complex. These aspects must be taken into consideration for management decisions and restoration strategies to be effective.