No description available.

Excess sediment in streams is harmful to the environment, economy, and human health. Streambanks account for an estimated 7-92% of sediment and 6-93% of total-phosphorus loads to streams depending on the watershed. Stream stabilization through stream restoration has become a common practice to satisfy the 2010 Chesapeake Bay total maximum daily load (TMDL) due its value in credits received per dollar spent. Bank erosion is most commonly credited through the Bank Assessment for Non-point source Consequences of Sediment (BANCS) framework, an empirically-derived model that predicts bankfull bank erosion rates using Bank Erodibility Hazard Index (BEHI), an indicator of bank stability, and Near-Bank Stress (NBS), an indicator of applied flow energy at bankfull discharge. This study assessed the BANCS framework in the Valley and Ridge physiographic province where it has not previously been applied. The spatial and temporal variability of erosion data was assessed to determine the impact of different erosion measurement schemes on bank erosion estimates and BANCS curves, and alternate NBS methods that capture flow energy beyond bankfull were applied. Three years of monthly erosion data on 64 streambanks were used to assess the spatial and temporal variability of erosion measurements and subsequently develop the erosion curves. Predicted erosion rates were then compared to measured erosion rates on three banks in the Valley and Ridge of Southwest Virginia. Analysis of spatial variability suggests bank retreat measurements should be made every three channel widths to reliably quantify reach-scale load estimates. Furthermore, a minimum monitoring period of 12 months is recommended to ensure seasonal patterns in bank retreat are captured. These results also bring into question the efficacy of the BANCS model as a crediting tool, as the developed statistical relationships between erosion rates, BEHI, and multiple NBS methods were not statistically significant. The limited number of significant curves had low r2 values (r2 < 0.1) indicating measures of NBS and BEHI do not adequately explain the natural variability of bank retreat in the Valley and Ridge of Southwest Virginia. / Master of Science / While sediment naturally occurs in streams, too much sediment in these systems is harmful to the environment, economy, and human health. Streambanks contribute an estimated 7-92% of sediment pollution into streams. Stabilizing streambanks with stream restoration has become a common practice to reduce sediment for the 2010 Chesapeake Bay pollutant diet. The sediment reduction of bank stabilization is most commonly estimated with the Bank Assessment for Non-point source Consequences of Sediment (BANCS) framework, a model that predicts bank erosion rates using Bank Erodibility Hazard Index (BEHI), an indicator of bank stability, and Near-Bank Stress (NBS), an indicator of flow energy when the stream channel is full of water. This study assessed the BANCS framework in the Southwest (SW) Virginia where it has not previously been applied. In this process, the variability of the erosion data in space and time was assessed to determine the impact of different erosion measurement methodologies on bank erosion estimates and BANCS equations. Additionally, alternate NBS methods that represent flow energy below, at, and above the channel being full were tested. Three years of erosion data on 64 streambanks were used to assess the variability of erosion measurements in space and time and create new BANCS erosion equations. Predicted erosion rates using the new erosion equations were then compared to measured erosion rates on three banks in the area. Analysis of variability in space suggests bank retreat measurements should be made every three channel widths to reliably estimate erosion volume along a length of stream. Furthermore, a minimum measuring period of 12 months is recommended to ensure seasonal differences in bank retreat are captured. The results also bring into question the effectiveness of the BANCS model as a tool to estimate sediment reduction for the Chesapeake Bay pollutant diet, as the developed equations between erosion rates, BEHI, and multiple NBS methods were not significant. The limited number of significant curves had low r2 values (r2 < 0.1) indicating the measures of NBS and BEHI do not explain the natural variability of bank retreat in the study area.

No / High levels of suspended solids are typically observed during the initial part of storms. Field evidence suggests that these suspended solids derive from the erosion of in-sewer sediment beds accumulated during dry and previous wet weather periods. Suspended sediment transport rate models within existing sewer network modeling tools have utilized inappropriate transport rate relationships developed mainly in fluvial environments. A process model that can account for the erosion of fine-grained highly organic in-sewer sediment deposits has been formulated. Values of parameters describing the increase in deposit strength with depth are required. These values are obtained using a genetic algorithm based calibration routine that ensures model simulations of suspended sediment concentrations that correspond to field data collected in a discrete length of sewer in Paris under known hydraulic event conditions. These results demonstrate the applicability of this modeling approach in simulating the magnitude and temporal distribution of suspended in-sewer sediment eroded by time varying flow. Further work is developing techniques to enable the application of this type of model at the network level.

Increased sediment loads within river catchments have well-documented detrimental effects on water quality and catchment management plans are required to address reduction and mitigation of these problems. In order to do this it is essential that tools are available that deliver reliable sediment generation data at appropriate temporal and spatial scales. Currently, most sediment generation models do not include bank erosion individually as a sediment source. Therefore, to enable improved accuracy in predictions of future sediment pressures under environmental change, explicit modelling of the rates of sediment production by the bank erosion is required to provide a more complete representation of the catchment sediment budget. In this study, an existing prototype national bank erosion index has been refined. Using Geographical Information Systems (GIS) digitised overlays, channel migration rates were calculated for several UK catchments. Relationships between the rate of channel bank erosion and factors controlling the rates of channel migration were investigated, including channel sinuosity, slope, upstream catchment area, and restriction of migration due to valley width. Significant correlations between bank erosion and sinuosity, upstream area and channel confinement were observed. The non-linear influence of channel planform geometry (curvature and sinuosity) on migration rates was further investigated using an existing meander migration model. A new bank erosion model was developed to incorporate the influence of both channel confinement and sinuosity. As the model incorporates the key physical controls on bank erosion, hence it is expected that it will have wide applicability in catchment- to national-scale bank erosion assessment. A computationally efficient catchment routing model was developed. Data output from a newly developed catchment overland sediment and runoff estimation model (ADAS APT) was used as input to the routing model. The newly developed bank erosion model and an existing floodplain sedimentation model were incorporated within the routing methodology to provide a catchment sediment budget model. The model was applied to the Exe catchment, Devon, UK and validated against observational data. Model estimations of annual sediment generation through bank erosion, sediment deposition on floodplains, and sediment load at the catchment outlet were within the range of observed values. The catchment sediment budget model developed in this thesis provides a more comprehensive representation of catchment sediment processes than existing alternative methodologies.

Master of Science / Department of Biological and Agricultural Engineering / Stacy Hutchinson / Military maneuvers result in significant physical and environmental impacts to the landscape. These impacts generally result in a loss of vegetative cover and increased watershed runoff and rate depending on vehicle speed, turning radius, and soil moisture content. Unless adequately monitored or mitigated, this increased runoff can lead to excessive soil erosion and gully formation. Past studies have revealed that these gullies can impact water quality from excessive erosion and create concerns regarding soldier safety. In order to better understand how gullies form and evolve overtime on military installations, a study is being conducted at Fort Riley, KS. In 2010, approximately forty gullies were identified, assessed, and measured using common erosion monitoring and surveying techniques. These gully locations, and any newly formed gullies, were remeasured using these same methods in 2012 to determine the rate of growth for each site with respect to width, depth, and headcut. Of fifty-nine gullies total, twenty one were initially included in this study. Upon further analysis including the utilization of watershed characteristics and land management techniques, eleven of the 21 utilized gullies were deemed appropriate to include in predictive assessment, as these eleven systems exhibited singular headcut migration. Multiple Regression Analysis was utilized to produce predictive equations for Headcut Growth. This equation [Headcut Growth = 0.666 + 0.137(Watershed Slope) – 0.478(Training Intensity) + 0.757(log[Watershed Area]) – 0.278(Drainage Density) – 0.0138(Above Ground Biomass Change) + 0.187(Burning Frequency] resulted in a model relationship of approximately 90%, with Watershed Slope being the most significant variable when an output Headcut Growth was reached.

Syfte: Syftet med studien var att studera förekomst av riskfaktorer för och attityder till dentala erosionsskador bland högskolestudenter. Metod: Studien var en prospektiv tvärsnittsstudie där data samlades in via en gruppenkät genom ett klusterurval av studenter på en högskola i södra Sverige. Resultat: Riskfaktorer som de 99 deltagarna uppvisade var frukt- och fruktjuicekonsumtion, tid framför dator/tv/läsplatta och träning. Totalt konsumerade 24,2 % frukt och 17,2 % fruktjuice mer än tre gånger i veckan. En statistisk signifikant skillnad att kvinnor åt mer frukt än män kunde påvisas. Vid tid framför dator/tv/läsplatta var det totalt 23,5 % som spenderade mer än fem timmar om dagen. Av deltagarna var det totalt 25,5 % som tränade mer än tre gånger i veckan där män tränade statistisk signifikant mer än kvinnor. Deltagarna var mer tveksamma till att förändra en vana om risk för dentala erosionsskador fanns än om besvär uppkom i form av smärta som ilningar/isningar i tänderna. Deltagarna i den äldre åldersgruppen (22-42 år) var statistisk signifikant mer tveksamma till att förändra en vana om tändernas färg skulle påverkas av dentala erosionsskador. / Objective: The aim of this study was to examine occurrence of risk factors and attitudes to erosive tooth wear among university students. Method: This study was a prospective cross-sectional study where data were collected by a group survey through a cluster sampling of students at a university in southern Sweden. Results: Risk factors that the 99 students showed were fruit-, fruit juice consumption, time in front of computer/tv/tablet computer and exercise. A total of 24,2 % consumed fruit and 17,2 % consumed fruit juice more than three times/week. A statistically difference that woman ate more fruit then men could be demonstrated. It was a total of 23,5 % who spent time in front of the computer/tv/tablet more than five hours/day. It was a total of 25,5 % who exercised more than three times/week which men exercised statistically significantly more than woman. The participants were more doubtful to changes in their habits if they had risk to develop erosive tooth wear then when a trouble occurred like pain in form of tooth sensitivity. Participants in the older age group (22-42 years old) were statistically more doubtful to change a habit if the color of the teeth would be affected by erosive tooth wear.

published_or_final_version / Applied Geosciences / Master / Master of Science

This dissertation represents a unique contribution to the Spanish literature of soil erosion. The author of this document has written and published "Procesos y control de la erosion", a textbook about the engineering of soil erosion processes and the design of the most up-to-date methods and products used for erosion control. The text has been presented in Appendix A.Besides the above, the author of this dissertation is an active committee member at the International Erosion Control Association (IECA), specifically the International Development and the SOIL Fund programs. IECA members are drawn from individuals and erosion control business of different sizes. However, there was a lack of knowledge within IECA members about the formation of post-fire water repellent layers. For instance, Appendix B is represented by an article written by the author of this document, published in Environmental Connection (Volume 2, Issue 3), on July of 2008. The article gives a general description of what post-fire water repellency is, how is it formed, what factors affect it, its consequences on soil erosion, and how to control soil erosion on an efficient way when such a layer has been formed as a consequence of fire.Finally, Appendix C is a research paper in process of submission to the International Journal of Wildland Fire, about the formation of post-fire water repellent layers on Chilean Monterrey pine plantations. Since water repellent layers following wildfires have never been documented on Chilean soils, the need for such a publication is urgent, because Chilean land managers have been ignorant of such phenomenon.

No description available.

The general aim of this study was to gain an insight into the nature of gully erosion at Golden Gate Highlands National Park. In order to achieve this the spatial and temporal characteristics of six gullies were investigated by examining their typological and morphological characteristics, the relationship between their morphometric properties and their increase in extent over a 39 year period (1952-1991). Where possible these findings and observed gully forms were related to initiating factors. Extensive field surveys and measurements were carried out to ascertain the typological and morphological characteristics of each gully. The results of the field measurements were then statistically analyzed using linear regression analysis, principal component analysis and canonical variate analysis. These methods of analysis were used to get an indication of the relationships taht exist between the morphometric properties of the gullies as well as to highlight the similarities and differences that exist between them. These results showed that the morphometric varaibles of the gullies are strongly interrelated. Furthermore they revealed that the six gullies could be divided into three broad groups on the basis of their morphometric and sediment properties. The gullies within two of the three groups were found to be similar not only in terms of the above mentioned but they also occur on same facing slopes of similar gradients and appear to have been initiated by similar processes. Differences occurring within and between the gully groups were attributed to varying combinations of initiating factors. Aerial photographs from 1952 and 1984 were used together with surverys to map the extent and development of five of the six gullies - teh remainign gully was only initiated in 1988. The 1952 and 1984 photographs were selected as they represented the earleist and most recent photographs to be taken of the area. The maps show the gullies to have experienced a greater amount of growth during the 1984 - 1991 period than during the 1952 - 1984 period. This finding was attributed to the sporadic nature of gully growth. The spatial location of the gullies in relation to one another appears to have had little influence on their typological and morphological characteristics. However, their spatial location within the landscape has undoubtedly influenced these properties. In general the research described has shown that the spatial and temporal differences of the gullies occurring in the park are the result of various combinations of endogenous and exogenous factors that governed the initiation and development of each gully.