<p>A gravel pit west of Galt exposed about 6m of shallow braided outwash gravels which overlie deposits of unknown origin with eroded topography. The outwash shows two cycles of coarse sediment deposition with a relatively quiet period between. The lower cycle fines upwards from coarse gravel, through cross-bedded pebbly sand, to silty ripple-drift. The upper cycle erodes the silty sand and coarsens upwards from pebbly sand cross-beds to cobble gravel of longitudinal bars. These bars can be shown by their internal sandy horizons and stoss side sandy deposits to have grown by deposition at their upstream end. </p><p>The two major depositional cycles are related to north-westward flowing meltwater from the glacier as it stood at the Paris and Galt moraines respectively with the quiet period representing the time of retreat between the moraines. Subsequent melting to the north initiated an ice-contact spillway which ended the outwash deposition west or Galt. </p> / Thesis / Bachelor of Science (BSc)

Headwater streams provide diverse habitat for aquatic organisms, drinking water for downstream communities and abundant recreational activities. The addition of in-stream wood to headwater channels can influence the hydrology, morphology and ecology of the system. The recruitment of wood to the channel and the export mechanisms determine the wood load and structure types formed in-stream, thus altering the channel’s morphological response. This research examined the effects of in stream wood on channel morphology in two headwater streams along the eastern slopes of the Canadian Rocky Mountains; Lyons East (LE) and Corolla Creek (CC). Lyons East has natural and anthropogenic disturbance (burned and salvage-logged) in the watershed, while Corolla Creek has anthropogenic (grazing and recreation) disturbances in the watershed. An assessment of the longitudinal spatial distribution and a reach-scale geomorphic classification were conducted to investigate the impacts of in-stream wood on channel morphology, pool formation and sediment storage. The spatial distribution of in-stream wood was 1.49 sites/100m for both watersheds, results that are comparable to previously conducted studies in similar geographic watersheds. The types of structures found in both watersheds were predominately jam formations (LE - 43%, CC - 47%), which is consistent with the wood loading and spatial distribution conceptual model previously developed by Whol and Jaeger (2009) for in-stream wood accumulations in mountain streams. At the reach-scale level of analysis, in-stream wood was found to impact channel morphology and pool forming processes. The addition of wood to the stream caused half of the studied reaches to have forced pool-riffle morphology. For all six selected study reaches, there was a decrease in expected pool spacing and an increase in the diversity of pool types. The relationship between wood-affected pools and sediment storage was examined and the results show that more sediment was stored in the burned/salvage logged reaches. Cohesive sediment was stored only in pools influenced by wood structures for half of the studied reaches. V* was generally higher in wood-affected pools for five of the six study reaches. The weighted average (V*w), which provides information regarding the storage of cohesive at the reach scale, was greater in Lyons East than in Corolla Creek. The presence of both exposed bedrock in the channel as well as the amount of vegetation are possible reasons for the smaller amounts of sediment observed in Corolla Creek. The observations from this reach scale investigation led to the development of a conceptual model, which can be used to predict the location of cohesive sediment storage in headwater streams of the Oldman River Basin. This model highlights the relationship between simultaneous recruitment of in-stream wood and sediment from local sources as a mechanism for protecting and storing cohesive sediment deposits. This research examined channel responses to in-stream wood within the context of land-use planning and Alberta’s Water for Life Strategy. There was evidence of lateral channel migration in the floodplain of both watersheds. At some sites, the channel shifted up to 30 metres while in other sections of the watershed, the channel was confined within a narrow valley. Accordingly, it is recommended that the current salvage logging guidelines be changed to include a flexible riparian buffer that would more appropriately reflect the diversity in riparian widths throughout the watersheds. In addition the best management practice is to allow natural in-stream wood processes to evolve and not to remove in-stream wood from the channel. The in-stream wood provides diverse aquatic habitat and the cycle of wood being recruited and being in the stream is part of the natural ecosystem in forested environments.

Headwater streams provide diverse habitat for aquatic organisms, drinking water for downstream communities and abundant recreational activities. The addition of in-stream wood to headwater channels can influence the hydrology, morphology and ecology of the system. The recruitment of wood to the channel and the export mechanisms determine the wood load and structure types formed in-stream, thus altering the channel’s morphological response. This research examined the effects of in stream wood on channel morphology in two headwater streams along the eastern slopes of the Canadian Rocky Mountains; Lyons East (LE) and Corolla Creek (CC). Lyons East has natural and anthropogenic disturbance (burned and salvage-logged) in the watershed, while Corolla Creek has anthropogenic (grazing and recreation) disturbances in the watershed. An assessment of the longitudinal spatial distribution and a reach-scale geomorphic classification were conducted to investigate the impacts of in-stream wood on channel morphology, pool formation and sediment storage. The spatial distribution of in-stream wood was 1.49 sites/100m for both watersheds, results that are comparable to previously conducted studies in similar geographic watersheds. The types of structures found in both watersheds were predominately jam formations (LE - 43%, CC - 47%), which is consistent with the wood loading and spatial distribution conceptual model previously developed by Whol and Jaeger (2009) for in-stream wood accumulations in mountain streams. At the reach-scale level of analysis, in-stream wood was found to impact channel morphology and pool forming processes. The addition of wood to the stream caused half of the studied reaches to have forced pool-riffle morphology. For all six selected study reaches, there was a decrease in expected pool spacing and an increase in the diversity of pool types. The relationship between wood-affected pools and sediment storage was examined and the results show that more sediment was stored in the burned/salvage logged reaches. Cohesive sediment was stored only in pools influenced by wood structures for half of the studied reaches. V* was generally higher in wood-affected pools for five of the six study reaches. The weighted average (V*w), which provides information regarding the storage of cohesive at the reach scale, was greater in Lyons East than in Corolla Creek. The presence of both exposed bedrock in the channel as well as the amount of vegetation are possible reasons for the smaller amounts of sediment observed in Corolla Creek. The observations from this reach scale investigation led to the development of a conceptual model, which can be used to predict the location of cohesive sediment storage in headwater streams of the Oldman River Basin. This model highlights the relationship between simultaneous recruitment of in-stream wood and sediment from local sources as a mechanism for protecting and storing cohesive sediment deposits. This research examined channel responses to in-stream wood within the context of land-use planning and Alberta’s Water for Life Strategy. There was evidence of lateral channel migration in the floodplain of both watersheds. At some sites, the channel shifted up to 30 metres while in other sections of the watershed, the channel was confined within a narrow valley. Accordingly, it is recommended that the current salvage logging guidelines be changed to include a flexible riparian buffer that would more appropriately reflect the diversity in riparian widths throughout the watersheds. In addition the best management practice is to allow natural in-stream wood processes to evolve and not to remove in-stream wood from the channel. The in-stream wood provides diverse aquatic habitat and the cycle of wood being recruited and being in the stream is part of the natural ecosystem in forested environments.

This thesis aims to improve our understanding of how riverine ecosystems respond to dam removal. Riverine and particularly riparian ecosystems are among the most variable and important features of all landscapes. They connect landscape elements both longitudinally and laterally, and are governed by processes such as flooding, erosion and deposition that create dynamic, diverse and heterogeneous habitats. In fact, riparian zones are among the world’s most species-rich habitats. Worldwide there are millions of dams that fragment stream and river systems, regulate flows and degrade ecosystems. Dams impact freshwater, marine and terrestrial ecosystems and threaten biodiversity by disrupting organism movements and energy flows in the landscape. An important upstream effect of dams is inundation of habitats and development of new shorelines around impounded areas. Effects downstream of dams are mainly caused by changed hydrological regimes and retention of organic and inorganic materials in reservoirs, leading to reduced transport and dispersal of for example seeds to reaches downstream. The removal of dams create expectations that biota will eventually recover. We have studied a number of dam removal projects in Sweden. Our experimental results showed that following dam removal, newly exposed soils in former impoundments were rapidly colonized by pre-removal species. Their species richness increased slightly with time and their species composition indicated a slow change towards that in the reference site. In addition, the vegetation in formerly impounded areas showed a direction of change from lentic riparian plants (high proportion of aquatics) towards lotic ones, consisting of native perennials typical of free-flowing streams. We also found that the apprehensions that former impoundments would turn into pools of mud did not come true; in fact, a process towards more pristine channel morphology was observed. After removal there was erosion and downstream transport of sediment. We found only minor effects on macroinvertebrate communities. For example, a few species decreased over the years, suggesting that dam removal in itself might cause a temporary disturbance. This highlights the importance of long-term studies after dam removal, and also the importance of comparisons with pre-removal conditions and stretches unaffected by dams. Thorough documentation of executed dam removal projects and distribution of the results and experiences are tremendously important in the planning process of future decommissioning projects. Also, our experiences have taught us that in order to attain a successful dam removal it is important to involve stakeholders such as non-governmental organizations and local inhabitants in the process.

Erosion and sediment delivery from upland areas to waterbodies is a major problem impacting water quality in the United States and elsewhere. Measures to reduce these impacts are either targeted at reducing erosion on-site or at reducing delivery of sediment to waterbodies. AMEENA (Areal Modeling of Erosion for Environmental Nonpoint Applications) is a spatially distributed model that estimates erosion and deposition on a watershed scale by predicting erosion and transport over the landscape surface. Erosion is predicted based on the Revised Universal Soil Loss Equation (RUSLE), and sediment transport capacity is estimated as a function of upslope flow volume, local gradient, and land use. Gross erosion is routed to edge-of-stream with a routing algorithm that iteratively compares available sediment with transport capacity on a cell by cell basis from ridge cells to stream cells. The model is implemented completely within a raster GIS to facilitate use of the model as a tool to readily evaluate impact of land use practices on sediment delivery to streams. AMEENA was validated using field data of net erosion and sediment deposition from three field studies. AMEENA predicted the spatial distribution of net erosion and deposition better than WaTEM/SEDEM which is a distributed parameter erosion model based on a similar modeling approach. AMEENA's suitability to simulate the impact of management practices such as filter strips and critical area planting was evaluated on plot (profile) scale and catchment scale simulations. Results of plot scale simulations were intuitive and the model proved more reasonable for these scenarios than did RUSLE2 and WEPP. The catchment scale study highlighted features of AMEENA that are not available in RUSLE2 and WEPP in terms of identifying erosion “hot spots” and the ability to utilize the explicit sediment flow path identification in locating best placement of off-site sediment control measures. Since AMEENA does not account for in-stream erosion processes, it is not suitable for simulating areas dominated by channel or gully erosion. / Ph. D.

Relatively little work has been done to understand how coarse grained sediments behave near culverts. Particularly for embedded culverts, sediment transport must be understood to achieve sustainable culvert designs for aquatic organism passage and peak discharge requirements. Several culvert sites in the Wasatch Mountains of Utah were studied through the spring flood season of 2014. Data obtained from the culvert sites were used to create numerical models with the Sedimentation and River Hydraulics Two-Dimensional model. The field sites and numerical model were used to study deposition of sediments at the entrance to culverts, sediment replenishment inside culverts, and lateral fining within the culvert barrel. Each element of the study was observed in the field. It was shown that the Sedimentation and River Hydraulics Two-Dimensional model is a useful tool to simulate the observed phenomenon of sediment deposition upstream of culverts, sediment replenishment, and lateral fining. Sedimentation and River Hydraulics Two-Dimensional model should be used in culvert design procedures as a means to understand sediment transport conditions.This work documents the first time that deposition of sediments upstream of a culvert and lateral fining within a culvert barrel have been successfully modeled. The work shows that culvert replenishment occurs naturally in many scenarios and should be simulated as part of the culvert design process. The results from this work will be useful for future design guidelines for culvert installations.

Fine-grained sediment accumulation in the interstices of gravel beds is a key factor in degrading riverine habitats. However, interstitial deposits are highly dynamic and are not sufficiently understood. This work enhances the understanding of interstitial fine sediment deposition by investigating interstitial storage and ingress, flow, suspended sediment and gravel bed character. Furthermore, this work introduces a numerical suspended sediment deposition model with the power to predict patterns of interstitial ingress. The investigation of interstitial deposition were carried out on two levels. Both data orginating from flume experiments and from three locations of the River Culm, Devon, UK was collected. The experimental data showed the significant influence of small scale variations in flow and bed character and their influence on interstitial ingress. The field investigation showed clear differences in interstitial fine-grained sediment for the different river reaches and an overall higher interstitial ingress compared to recent published data. The numerical model development was realised in a two-step approach. First, the model was coded and calibrated for the flume scale processes and, second, an upscaled reach scale model was devolped for the field data. This reach scale suspended sediment deposition model included flow information, for which depthaveraged two dimensional hydrodynamic models were developed with the software Delft3D. The overall explanatory power of the model at this state is not satisfactory with regards to local deposition distribution. A separate chapter discusses the possible causes and implications of this short coming for further research from a data aquisition and modelling perspective.

This study focused on development of a continuous watershed-scale modelling approach capable of evaluating sediment removal performance of vegetative filter strips (VFS). This was done by integrating the single-event hydrologic and sediment transport model AGNPS with the event-based VFS model (VFSMOD) applying the methodology developed by Sebti and Rudra (2010), and also through the development and incorporation of sub-models capable of describing changes in hydrologic conditions between rainfall events into the integrated models. For modeling purposes, the buffer zone is divided to segments called “buffer cells”. The upstream source area corresponding to each buffer cell and the flow-path connecting the area to the stream are identified, and runoff and sediment generated within each area is simulated for each event applying AGNPS. Using VFSMOD, performance analysis of VFS is conducted for each buffer cell. By applying the developed “continuous simulation” sub-models the hydrologic conditions prior to each event were determined.

Damming disrupts natural sediment flow to downstream resulting in legacy sediment accumulation. Legacy sediments have been well investigated in streams throughout the Piedmont region; however, there is no research of legacy sediments following dam removal in low-gradient Coastal Plain streams. Research objectives were to: characterize legacy sediments in a low-gradient stream restoration, quantify pre-impoundment accretion and carbon dynamics, and assess current sediment deposition rates via 14C analyses within sediment cores and sediment collection tiles. Carbon accumulation and accretion rates of modern tidal sediment have reached that of the tidal relic benchmark and current sediment deposition rates are similar between the natural reference and restored tidal wetlands. At this site, the pattern of legacy sediment accumulation and stream incision was reversed relative to previous studies in higher gradient systems. Results suggest in dam impacted Coastal Plain streams, legacy sediment may become a benefit rather than a liability for downstream tidal wetlands.

No description available.