Large woody debris (LWD) is an important component of forest ecosystems and provides structural complexity to small streams. Riparian buffers are intended to provide long term supplies of LWD, but post harvest windthrow often occurs. To document the impacts of windthrow in riparian buffers and identify the components needed for small stream LWD recruitment modeling, I sampled 39 small streams at the Malcolm Knapp Research Forest (MKRF) and on Vancouver Island. I took two basic approaches. In the small stream experiment at MKRF a series of small clearcuts were harvested in 1998 in a 70 year old second growth stand. I measured LWD in 10m and 30m buffer treatments, and in the unharvested control. I added samples in mature and old-growth stands for comparison. In the second approach, I retrospectively sampled buffers that were exposed by harvesting from 0-20yrs ago on southwestern and northeastern Vancouver Island. In both studies, all logs greater than 7.5 cm diameter at mid-creek, in decay class 1 to 4 that spanned at least part of stream channel width were measured. There was no significant difference in the number of spanning and in-creek logs in 10m and 30m buffer given the short term monitoring of woody debris in the buffers. The majority of windthrown trees were still suspended above the stream channel years after a windthrow event. The height above stream was negatively correlated with log decay class and the buffer age class. The number of logs was higher in immature stands than mature stands. As the stems per hectare in riparian stands increases, so does the frequency of spanning LWD. The frequency of logs in decay classes 3 and 4 was higher in older buffers, and deciduous LWD decayed more quickly than conifers. Interestingly, the log length was found to be shorter in advance stage of decay. Key elements in a conceptual model of LWD recruitment via windthrow are the geometry of initial log position, log size, species and decay rate.

Large woody debris (LWD) is an important component of forest ecosystems and provides structural complexity to small streams. Riparian buffers are intended to provide long term supplies of LWD, but post harvest windthrow often occurs. To document the impacts of windthrow in riparian buffers and identify the components needed for small stream LWD recruitment modeling, I sampled 39 small streams at the Malcolm Knapp Research Forest (MKRF) and on Vancouver Island. I took two basic approaches. In the small stream experiment at MKRF a series of small clearcuts were harvested in 1998 in a 70 year old second growth stand. I measured LWD in 10m and 30m buffer treatments, and in the unharvested control. I added samples in mature and old-growth stands for comparison. In the second approach, I retrospectively sampled buffers that were exposed by harvesting from 0-20yrs ago on southwestern and northeastern Vancouver Island. In both studies, all logs greater than 7.5 cm diameter at mid-creek, in decay class 1 to 4 that spanned at least part of stream channel width were measured. There was no significant difference in the number of spanning and in-creek logs in 10m and 30m buffer given the short term monitoring of woody debris in the buffers. The majority of windthrown trees were still suspended above the stream channel years after a windthrow event. The height above stream was negatively correlated with log decay class and the buffer age class. The number of logs was higher in immature stands than mature stands. As the stems per hectare in riparian stands increases, so does the frequency of spanning LWD. The frequency of logs in decay classes 3 and 4 was higher in older buffers, and deciduous LWD decayed more quickly than conifers. Interestingly, the log length was found to be shorter in advance stage of decay. Key elements in a conceptual model of LWD recruitment via windthrow are the geometry of initial log position, log size, species and decay rate.

Large woody debris (LWD) is an important component of forest ecosystems and provides structural complexity to small streams. Riparian buffers are intended to provide long term supplies of LWD, but post harvest windthrow often occurs. To document the impacts of windthrow in riparian buffers and identify the components needed for small stream LWD recruitment modeling, I sampled 39 small streams at the Malcolm Knapp Research Forest (MKRF) and on Vancouver Island. I took two basic approaches. In the small stream experiment at MKRF a series of small clearcuts were harvested in 1998 in a 70 year old second growth stand. I measured LWD in 10m and 30m buffer treatments, and in the unharvested control. I added samples in mature and old-growth stands for comparison. In the second approach, I retrospectively sampled buffers that were exposed by harvesting from 0-20yrs ago on southwestern and northeastern Vancouver Island. In both studies, all logs greater than 7.5 cm diameter at mid-creek, in decay class 1 to 4 that spanned at least part of stream channel width were measured. There was no significant difference in the number of spanning and in-creek logs in 10m and 30m buffer given the short term monitoring of woody debris in the buffers. The majority of windthrown trees were still suspended above the stream channel years after a windthrow event. The height above stream was negatively correlated with log decay class and the buffer age class. The number of logs was higher in immature stands than mature stands. As the stems per hectare in riparian stands increases, so does the frequency of spanning LWD. The frequency of logs in decay classes 3 and 4 was higher in older buffers, and deciduous LWD decayed more quickly than conifers. Interestingly, the log length was found to be shorter in advance stage of decay. Key elements in a conceptual model of LWD recruitment via windthrow are the geometry of initial log position, log size, species and decay rate. / Forestry, Faculty of / Graduate

Submitted by Irene Nascimento (irene.kessia@ufpe.br) on 2016-06-22T16:53:27Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) JESCE JOHN DA SILVA BORGES 2016.pdf: 8055827 bytes, checksum: 6b2c6f2d1b046abae4869d55dfd1b8c2 (MD5) / Made available in DSpace on 2016-06-22T16:53:27Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) JESCE JOHN DA SILVA BORGES 2016.pdf: 8055827 bytes, checksum: 6b2c6f2d1b046abae4869d55dfd1b8c2 (MD5) Previous issue date: 2016-01-21 / A investigação geotécnica é uma etapa essencial para a elaboração de projeto de engenharia. A utilização de um programa adequado minimiza os riscos. Para se avaliar o comportamento dos solos colapsíveis, é necessário utilizar técnicas de ensaios que simulem as condições a que o solo será submetido. A pesquisa tem por objetivo avaliar o módulo de elasticidade, a resistência de ponta e a variação de volume em campo de um solo colapsível do conjunto Residencial Nova Petrolina em Petrolina-PE, com e sem a inundação prévia. Para tanto, foram utilizados em campo os equipamentos Light Weight Deflectometer – LWD, Expansocolapsômetro, Penetrômetro Dinâmico Ligeiro (Dynamic Probing Light – DPL), Penetrômetro Estático (PE) e a caracterização física do solo foi realizada em laboratório. O solo é preponderantemente arenoso, sua resistência de ponta cresce com a profundidade, chegando a um valor médio de 12,85 MPa para profundidade de 1,20 m, a inundação reduz a resistência em torno de 84%. O módulo de elasticidade varia de 46,3 a 79,2 MPa e a inundação causa uma redução de 88%. A inundação provocou uma redução na tensão de ruptura em 36%. Há uma boa correlação (R²>0,80) entre o módulo de elasticidade obtido com o LWD e o índice de resistência a penetração dinâmica (DPL). A partir dos resultados do LWD, estabeleceu-se um critério de identificação de solo colaspível através do coeficiente KLWD, atestando que o solo de Petrolina apresenta suscetibilidade ao colapso: alto para KLWD > 4,20, baixo para KLWD < 2,78 e médio para KLWD entre 2,78 e 4,20. Portanto, assim como os penetrômetros, a aplicação do LWD em solos colapsíveis demonstrou ser uma técnica promissora na avaliação da perda de rigidez do solo devido à inundação, como também se destaca sua praticidade na execução e obtenção de resultados imediatos sem necessidade de cálculos posteriores, permitindo uma análise em campo de forma imediata. / Geotechnical research is an essential step for the development of an engineering project. The use of a suitable research program minimizes risks. To evaluate the behavior of collapsible soils, it is necessary to use technical tests simulating the conditions in which the soil will be submitted. The research aims to evaluate the elasticity modulus, the tip resistance, the variation of volume in the collapsible soil of “Residential Nova Petrolina” in Petrolina-PE, with and without previous flood. Therefore, were used in the field the Light Weight Deflectometer equipment - LWD, Expansocolapsometer, Dynamic Probing Light - DPL, Static Penetrometer (PE) and the physical characterization of soil was performed in the laboratory. The soil is mainly sandy, the tip resistance grows with depth, reaching an average value of 12.85 MPa for a depth of 1.20 m, flooding reduces the resistance around 84%. The elasticity modulus varies from 46.3 to 79.2 MPa and flooding causes a 88% reduction. The flooding caused a reduction in the breakdown voltage by 36%. There is a good correlation (R²> 0.80) between the elasticity modulus obtained from the LWD and the dynamic penetration resistance index (DPL). From the results of the LWD, a criterion for the identification of collapsible soils was established through kLWD coefficient, attesting that Petrolina’s soil presents the following susceptibility to collapse: high to KLWD> 4.20, low to KLWD <2.78 and average for KLWD between 2.78 and 4.20. Therefore, as well as the penetrometers, the LWD application on collapsible soils proved to be a promising technique in the evaluation of soil rigidity loss due to flooding, as it also stands out for its practical implementation and for obtaining immediate results without the need for further calculations, allowing an immediate analysis.

No description available.

Sind Geothermiebohrungen nicht fündig, bedeutet dies, dass das Wasser im Untergrund nicht die während der Projektplanung prognostizierte Temperatur hat bzw. nicht in ausreichender Schüttung zu Tage gefördert werden kann. Die Folgen sind meist der Projektabbruch und hohe finanzielle Verluste für den Investor. Beim Bohren nach Öl und Gas bringt schon jetzt nur eine von sieben Erkundungsbohrungen das gewünschte Ergebnis. Da die noch vorhandenen Öl- und Gasvorkommen immer schwieriger zu erschließen sind, steigen mit dem Risiko von Fehlbohrungen die Kosten und damit folgerichtig auch die Brennstoffpreise. Ein Grund für die aufgezeigte Problematik ist, dass die bisher in Bohrgarnituren eingesetzten Messgeräte zwar das Umfeld um die Bohrung, nicht aber den Bereich vor dem Bohrmeißel erkunden können. Seit Ende 2007 arbeitet eine Forschergruppe an einem neuen Messgerät, das in der Lage sein soll, seismische Energie gezielt in Bohrrichtung zu verstärken. Für die Manipulation der Abstrahlrichtung wird das bisher noch nicht in der Seismik genutzte Phased Array Prinzip angewandt. Die bisherigen Versuche im Labormaßstab waren erfolgversprechend. In der vorliegenden Arbeit wird untersucht, wie ein seismisches Messgerät in eine Bohrgarnitur integriert und im Feld eingesetzt werden könnte. Behandelt werden drei wesentliche Fragestellungen: (1) In welchem Bereich vor dem Bohrmeißel soll die seismische Energie verstärkt werden? Eine Richtbohrgarnitur kann zwar durch den Untergrund gelenkt werden, ihr Aktionsradius hängt jedoch von verschiedenen Randbedingungen ab. (2) An welcher Stelle in der Bohrgarnitur soll das Messgerät platziert werden? Ganz vorne befindet sich der Bohrmeißel, dahinter typischerweise die Steuer- und Messgeräte zur Richtungssteuerung der Garnitur, denn der Bohrpfad lässt sich umso genauer steuern, je geringer die Distanz zwischen diesen Geräten und dem Bohrmeißel ist. (3) Wann und wie soll gemessen werden? Jede zusätzlich für Messungen benötigte Zeitspanne ist ein Kostenfaktor, der die Bohrung verteuert. Die Versorgung des Messgeräts mit Energie und die Ansteuerung hängen darüberhinaus von der technischen Ausstattung der Bohrgarnitur und dem Zeitpunkt der Messung im Bohrprozess ab. Angesichts der Fragestellungen wird eine Analyse der bestehenden und neuen Systeme der Tiefbohrtechnik und der Seismik vorgenommen und auf dieser Grundlage ein ganzheitliches Modell entwickelt. Anhand dieses zentralen Modells werden mehrere Konzepte für Richtbohrgarnituren mit integriertem seismischem Messgerät erarbeitet sowie bewertet und die Wechselwirkungen zwischen Mess- und Bohrprozess untersucht. Ein Ergebnis der Arbeit ist die Definition des Begriffs „Vorauserkundung“. Um eine Vorauserkundung durchführen zu können, ist es wichtiger, das Messgerät in eine Richtbohrgarnitur zu integrieren, die hohe Bohrlochkrümmungen ermöglicht, als es so nahe wie möglich hinter dem Bohrmeißel zu platzieren. Mit den im Modell erarbeiteten Bewertungskriterien kann die Weiterentwicklung sowie die praktische Anwendung des seismischen Messgeräts begleitet und beurteilt werden.

Those who frequent the coastline may be accustomed to seeing driftwood washed onshore, some of it having seemingly found a home there for many years, others having been freshly deposited during the last set of storms; However, if a passerby were to take a closer look at the driftwood on the coastline, they may notice that some of these logs – also known as Large Woody Debris (LWD) – are anchored in place, a practice which is generally used for the purpose of stabilizing the shoreline or reducing wave-induced flooding. Records of existing anchored LWD project sites date back to 1997 and anecdotal evidence suggests that the technique has been used since the mid-1900’s in coastal British Columbia (BC), Canada, and Washington State, USA. Now, with an increased demand for natural and nature-based solutions, the technique is again gaining popularity. Despite this, the design of anchored LWD has largely been based on anecdotal observations and experience, as well as a continuity of design practices from the river engineering field. To date, there is no known peer-reviewed literature on the design or efficacy of LWD protection systems in a coastal environment. In 2019, the “Efficacy and Design of Coastal Protection using Large Woody Debris” research project was initiated to determine if LWD are effective at stabilizing the shoreline under wave action, if they are effective at reducing wave run-up, and if they are durable enough to meet engineering requirements for shore protection. In addition, the project aimed to determine the optimum configuration of LWD for design purposes. To meet these objectives, this study included the following work: (1) field studies of existing LWD installations, (2) experimental modeling of beach morphology with and without LWD structures, (3) experimental modeling of wave run-up with and without LWD structures, and (4) development of preliminary design guidance. The first phase of the project included field investigations at 15 existing anchored LWD sites in coastal BC and Washington State. Site characteristics, design techniques, and durability indicators were examined and correlated to a new design life parameter: ‘Effective Life’. Six primary installation techniques were observed: Single, Multiple, Benched, Stacked, Matrix, and Groyne. Observed durability and/or performance issues included: missing LWD, erosion, arson, wood decay, and anchor corrosion/damage. The Effective Life of anchored LWD was found to be strongly correlated to the tidal range and the upper beach slope for all installation types, and the LWD placement elevation relative to the beach crest elevation for single, shore-parallel structures. The many noted durability issues and ineffectiveness as mitigating erosion indicates that existing design methods for anchored LWD have not generally been effective at providing coastal protection and meeting engineering design life requirements. A comprehensive set of over 60 experimental tests were completed as part of the overall research program. Thirty-two (32) tests were analyzed as part of this study relating to the morphological response of a gravel beach with and without various LWD configurations. The tests were conducted within a wave flume at the National Research Council’s Ocean, Coastal and River Engineering Research Centre (NRC-OCRE), at a large scale (5:1) based on site characteristics and LWD design characteristics made during the previous field investigations. Tests were also conducted to assess experiment repeatability, sensitivity to test duration, sensitivity to wave height, wave period, and relative water level, influence of regular waves, and influence of log roughness. The position of the most seaward LWD (whether considering distance or elevation) was found to be strongly linked to morphological response. A theoretical relationship was developed between LWD elevation and sediment volume change. Configurations which included LWD placement below the still water level, such as the Benched configuration, were found to be most effective at stabilizing the beach profile. As part of the experimental modeling program, 24 tests were also conducted for the purpose of estimating the effect of LWD design configuration on wave run-up. In total, six different beach and LWD configurations were tested under a base set of four regular wave conditions. The study findings indicated that anchored LWD may increase wave run-up relative to a gravel beach with no structures. In particular, configurations with more logs tended to result in higher wave run-up. However, additional research is needed on the effect of LWD on wave run-up to confirm and expand these findings. There are a number of potential engineering, ecological, social, and economic benefits associated with anchored LWD installations if designed, installed, and monitored appropriately for the site conditions and user needs. To realize these potential benefits, significant additional research is needed on the topic. One of the most significant barriers to usage is a lack of information on how to effectively anchor LWD structures. However, this research project provides a baseline for future comprehensive studies on the effect and design of coastal protection using LWD. The project provides preliminary design considerations for the usage of LWD as coastal protection and contributes to the growing body of literature on nature-based solutions.

No description available.

Sind Geothermiebohrungen nicht fündig, bedeutet dies, dass das Wasser im Untergrund nicht die während der Projektplanung prognostizierte Temperatur hat bzw. nicht in ausreichender Schüttung zu Tage gefördert werden kann. Die Folgen sind meist der Projektabbruch und hohe finanzielle Verluste für den Investor. Beim Bohren nach Öl und Gas bringt schon jetzt nur eine von sieben Erkundungsbohrungen das gewünschte Ergebnis. Da die noch vorhandenen Öl- und Gasvorkommen immer schwieriger zu erschließen sind, steigen mit dem Risiko von Fehlbohrungen die Kosten und damit folgerichtig auch die Brennstoffpreise. Ein Grund für die aufgezeigte Problematik ist, dass die bisher in Bohrgarnituren eingesetzten Messgeräte zwar das Umfeld um die Bohrung, nicht aber den Bereich vor dem Bohrmeißel erkunden können. Seit Ende 2007 arbeitet eine Forschergruppe an einem neuen Messgerät, das in der Lage sein soll, seismische Energie gezielt in Bohrrichtung zu verstärken. Für die Manipulation der Abstrahlrichtung wird das bisher noch nicht in der Seismik genutzte Phased Array Prinzip angewandt. Die bisherigen Versuche im Labormaßstab waren erfolgversprechend. In der vorliegenden Arbeit wird untersucht, wie ein seismisches Messgerät in eine Bohrgarnitur integriert und im Feld eingesetzt werden könnte. Behandelt werden drei wesentliche Fragestellungen: (1) In welchem Bereich vor dem Bohrmeißel soll die seismische Energie verstärkt werden? Eine Richtbohrgarnitur kann zwar durch den Untergrund gelenkt werden, ihr Aktionsradius hängt jedoch von verschiedenen Randbedingungen ab. (2) An welcher Stelle in der Bohrgarnitur soll das Messgerät platziert werden? Ganz vorne befindet sich der Bohrmeißel, dahinter typischerweise die Steuer- und Messgeräte zur Richtungssteuerung der Garnitur, denn der Bohrpfad lässt sich umso genauer steuern, je geringer die Distanz zwischen diesen Geräten und dem Bohrmeißel ist. (3) Wann und wie soll gemessen werden? Jede zusätzlich für Messungen benötigte Zeitspanne ist ein Kostenfaktor, der die Bohrung verteuert. Die Versorgung des Messgeräts mit Energie und die Ansteuerung hängen darüberhinaus von der technischen Ausstattung der Bohrgarnitur und dem Zeitpunkt der Messung im Bohrprozess ab. Angesichts der Fragestellungen wird eine Analyse der bestehenden und neuen Systeme der Tiefbohrtechnik und der Seismik vorgenommen und auf dieser Grundlage ein ganzheitliches Modell entwickelt. Anhand dieses zentralen Modells werden mehrere Konzepte für Richtbohrgarnituren mit integriertem seismischem Messgerät erarbeitet sowie bewertet und die Wechselwirkungen zwischen Mess- und Bohrprozess untersucht. Ein Ergebnis der Arbeit ist die Definition des Begriffs „Vorauserkundung“. Um eine Vorauserkundung durchführen zu können, ist es wichtiger, das Messgerät in eine Richtbohrgarnitur zu integrieren, die hohe Bohrlochkrümmungen ermöglicht, als es so nahe wie möglich hinter dem Bohrmeißel zu platzieren. Mit den im Modell erarbeiteten Bewertungskriterien kann die Weiterentwicklung sowie die praktische Anwendung des seismischen Messgeräts begleitet und beurteilt werden.

The forestry is the main use of forests in Sweden which results in a number of positive aspects but also a number of negative effects on our nature. Aquatic ecosystems are specifically exposed to land use by the forest industry. The problem areas that arise are mainly discharge of nutrients, mercury, change in hydromorphology and local environment, sludge transport, absence of dead wood in streams and altered solar radiation. In order to reduce negative impact and protect natural populations of species but also to protect important ecosystems, there are a number of national prospective objectives and laws. From the year 2014, a number of prospective aims have been introduced to get a common view of the problem factors, but also to get a common representation of how the forestry measures should be carried out.  This work evaluated the width of the riparian buffer zone left along the 138 streams at final clearcutting in the Vindelälven catchment, comparing three periods: period 1 (year 2001-2007), period 2 (year 2008-2013) and period 3 (year 2014-2018).  The work also included a count of the number of dead wood objects that occur in 16 of the 138 streams in the study area. The method of the study is based on remote sensing using ArcGIS software, along with a field inventory to verify the remote sensing with reality. The results found from the study were that a significant increase in average minimum-width was shown between periods 1 and 3 (ANOVA, n = 138, df = 2, F = 5.083 and p = 0.007). The results from the average width were not significantly different but suggest a positive correlation between lower age of final clearcutting and the average width of the riparian zone. The density of dead wood in the streams of the study site did not give any significant differences or correlations depending on time period. What could be explained from the result was that the presence of beaver (Castor fiber) positively affected the amount of dead wood. To conclude, positive effects of the introduction of new objectives for riparian buffer zone management were indicated.  This is a sign that the forestry industry is moving towards implementing more sustainable methods. In addition, a method based on remote sensing for measuring riparian buffer zone widths was found to provide reliable estimates in the Vindelälven catchment, Västerbotten County. / Grip on Life IP