This thesis investigates the shore processes of Lake Pukaki to assess the suitability and performance of existing and potential future options for management of shore hazards. Following two successive raisings of the water level in the past sixty years, Lake Pukaki’s shoreline has undergone extensive erosion. Since mid 1987 until early 1988, shoreline erosion control structures (i.e. rock revetments, gabion baskets and groynes) were constructed and maintained to protect sections of road and other assets from further encroachment of the lake shoreline. The use of the RBR XR-620 pressure sensor in this study marks the first occasion when wave statistics were measured via instrumentation at Lake Pukaki. The mean significant wave height (Hs) identified for this study was 0.53 m, while the maximum recorded wave height was 1.84 m. Similar to other alpine lakes, Lake Pukaki has characteristics of steep plunging waves. The LAKEWAVE wave hindcasting model is used to describe the wave environment about the Lake Pukaki shoreline in terms of its optimum energy potential. The maximum wave height and wave period values estimated by LAKEWAVE have been found to compare well with measured wave statistics. Under the current wave climate, experienced during this study period (July 2010 – February 2011), the majority of the assessed rock revetments seem to be performing well. The Hudson and Van der Meer formula seemed to predict respectable stability thresholds that agree with what was observed in the field. The revetment at Site 3 is the biggest concern in terms of performance based on field observations. The short-period high-magnitude storm events, eventuating from a strong north/northwest wind flow, that coincide with high lake levels tend to cause the most significant erosion along the shoreline at Lake Pukaki and have a major influence of riprap stability. Other environmental factors including the steep nearshore profile, the glacial till backshore, groundwater and precipitation were identified as controlling factors leading to the success or failure of the shore protection structures.

Thesis (MScEng)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: Innovative and versatile coastal protection structures made of Geotextile Sand Containers (GSCs) are increasingly being incorporated into coastal management solutions because of their cost effective and environmentally friendly characteristics. This is as opposed to conventional ‘hard’ coastal protection solutions that utilise rocks and or concrete units to protect the coastline. With GSC structures being a relatively new coastal protection solution, few design and construction guidelines are available. Research into the behaviour of GSC structures under wave attack is on-going with particular emphasis on the hydraulic processes that affect GSC structures and cause them to fail. The use of GSC revetments as coastal protection solutions has become more popular in South Africa during recent times, particularly along the coastline of KwaZulu-Natal. However, the chosen design of these GSC revetments falls outside the range of applicability of the available design charts and stability equations. Therefore the hydraulic stability of these structures is largely unknown. The primary objective of this study is to investigate the effect of structure slopes and packing arrangements on the hydraulic stability of GSC revetments. The application of available design charts and stability equations was also evaluated. Two-dimensional physical modelling was undertaken and a total of 12 GSC revetment permutations were tested during the physical modelling test series. The results of the physical modelling showed that the structure slope had the most significant effect on the hydraulic stability. Steeper structure slopes were more hydraulically stable than gentler structure slopes. The packing arrangements of the GSCs had less of an effect on the hydraulic stability of the GSC revetments. Single layer GSC armour revetments matched or out-performed the equivalent double layer GSC revetments; while GSC revetments with GSCs orientated with the long axis perpendicular to the wave attack performed marginally better than the equivalent GSC revetments with GSCs orientated with the long axis parallel to the wave attack. The available design charts and stability equations were assessed against the results of the physical modelling and showed varying degrees of correlation. The stability equation proposed by Recio (2007) proved to be particularly accurate. / AFRIKAANSE OPSOMMING: Innoverende en veelsydige kusbeskermingstrukture wat van geotekstielsandhouers (GSH’s) gemaak is, word al hoe meer by kusbestuursoplossings ingesluit weens die kostedoeltreffendheid en omgewingsvriendelike aard daarvan. Dít is in teenstelling met konvensionele ‘harde’ kusbeskermingsoplossings, wat van rotse en/of betoneenhede gebruik maak om die kuslyn te beskerm. Aangesien GSH-strukture ’n betreklik nuwe kusbeskermingsoplossing is, is weinig ontwerp- en konstruksieriglyne beskikbaar. Navorsing oor die werkverrigting van GSH-strukture onder golfaanslag duur voort, met bepaalde klem op die hidrouliese prosesse wat GSH-strukture beïnvloed en die werking daarvan benadeel. Die gebruik van GSH-bedekte hellings as kusbeskermingsoplossings het in die laaste tyd al hoe gewilder geword in Suid-Afrika, veral langs die kus van KwaZulu-Natal. Tog val die gekose ontwerp van hierdie GSH-bedekte hellings buite die toepaslikheidsbestek van die beskikbare ontwerpriglyne en stabiliteitsvergelykings. Die hidrouliese stabiliteit van hierdie strukture is dus grotendeels onbekend. Die hoofoogmerk van hierdie studie was om ondersoek in te stel na die effek van struktuurhellings en pakformasies op die hidrouliese stabiliteit van GSH-bedekte hellings. Die toepaslikheid van beskikbare ontwerpriglyne en stabiliteitsvergelykings is ook geëvalueer. Tweedimensionele fisiese modellering is onderneem en altesaam 12 GSH-bedekte hellings is gedurende die fisiese-modelleringstoetsreeks getoets. Die resultate van die fisiese modellering toon dat die struktuurhelling die beduidendste effek op hidrouliese stabiliteit het. Steiler struktuurhellings was hidroulies meer stabiel as platter hellings. Die pakformasies van die GSH’s blyk ’n kleiner effek op die hidrouliese stabiliteit van die GSH-bedekte hellings te hê. GSH-bedekte hellings wat met ’n enkele laag GSH’s versterk is, het ewe goed of beter presteer as die keermure met ’n dubbele laag GSH’s, terwyl GSH-bedekte hellings met die lang-as van die GSH’s loodreg op die rigting van die golfaanslag effens beter presteer het as dié met die lang-as parallel met die golfaanslag. Die beskikbare ontwerpriglyne en stabiliteitsvergelykings is geëvalueer aan die hand van die resultate van die fisiese modellering, en het ’n wisselende mate van korrelasie getoon. Veral die stabiliteitsvergelyking van Recio (2007) blyk besonder akkuraat te wees.

Os rejeitos de construção e demolição representam, atualmente, grande volume de material desperdiçado no canteiro de obra e fábricas de pré-moldados de concreto. A necessidade da reciclagem para o desenvolvimento auto-sustentável, de materiais produzidos a partir dos rejeitos de construção, é de grande importância sob o impacto ambiental, além de proporcionar economia aos construtores e produtores de artefatos de cimento. Ensaios de concretos e argamassas, utilizando agregado reciclado, resultam bom desempenho mecânico e são relativamente mais leves quando comparados aos respectivos materiais utilizando agregados naturais. A fabricação de blocos de concreto com função estrutural, produzido com agregados reciclados de fração entre 2,4 mm e 9,5 mm, combinada à fração miúda de agregados naturais, possibilitam a execução de edifícios de pequena altura. A utilização da fração miúda reciclada, na preparação de argamassas de assentamento e revestimento, apresenta comportamento eficiente ao conjunto alvenaria-argamassa. A caracterização dos agregados, o estudo de traço, a análise do desempenho físico e mecânico dos blocos, prismas e paredes de alvenaria estrutural, bem como correlações de eficiência e análise da influência da argamassa de assentamento e de revestimento em relação à resistência de aderência à tração, é uma necessidade para o conhecimento e utilização deste material / The building and demolition rejects represent, nowadays, a great amount of wasted material in buildings and plants of pre-molded of concrete. The necessity of recycling for the self-supporting development of materials produced from the building rejects, is of great importance under the enviromental impact, and besides it provides savings for the builers and producers of concrete goods. Tests with concrete and mortar, utilizing recycled aggregate, show a good mechanical performance and they are lighter when compared to the respective materials using natural aggregate. The fabrication of concrete blocks with structural function, produced with recycled aggregate of fraction between 2,4 mm and 9,5 mm, combined to the small fraction of natural aggregate, make possible the construction of low height buildings. The application of the recycled small fraction, in the preparation of foundation and revetment mortar, shows efficient employed with the set masonry-mortar. The aggregate characterization, the study of the proportion of ingredients for concrete, the analysis of the physical and mechanical performance of the blocks, prisms and walls of structural masonry, as well the correlations of efficiency and analysis of the influence of foundation and revetment mortar, relating to the resistence of adherence to traction, are necessities for the knowledge and utilization of this material

Os rejeitos de construção e demolição representam, atualmente, grande volume de material desperdiçado no canteiro de obra e fábricas de pré-moldados de concreto. A necessidade da reciclagem para o desenvolvimento auto-sustentável, de materiais produzidos a partir dos rejeitos de construção, é de grande importância sob o impacto ambiental, além de proporcionar economia aos construtores e produtores de artefatos de cimento. Ensaios de concretos e argamassas, utilizando agregado reciclado, resultam bom desempenho mecânico e são relativamente mais leves quando comparados aos respectivos materiais utilizando agregados naturais. A fabricação de blocos de concreto com função estrutural, produzido com agregados reciclados de fração entre 2,4 mm e 9,5 mm, combinada à fração miúda de agregados naturais, possibilitam a execução de edifícios de pequena altura. A utilização da fração miúda reciclada, na preparação de argamassas de assentamento e revestimento, apresenta comportamento eficiente ao conjunto alvenaria-argamassa. A caracterização dos agregados, o estudo de traço, a análise do desempenho físico e mecânico dos blocos, prismas e paredes de alvenaria estrutural, bem como correlações de eficiência e análise da influência da argamassa de assentamento e de revestimento em relação à resistência de aderência à tração, é uma necessidade para o conhecimento e utilização deste material / The building and demolition rejects represent, nowadays, a great amount of wasted material in buildings and plants of pre-molded of concrete. The necessity of recycling for the self-supporting development of materials produced from the building rejects, is of great importance under the enviromental impact, and besides it provides savings for the builers and producers of concrete goods. Tests with concrete and mortar, utilizing recycled aggregate, show a good mechanical performance and they are lighter when compared to the respective materials using natural aggregate. The fabrication of concrete blocks with structural function, produced with recycled aggregate of fraction between 2,4 mm and 9,5 mm, combined to the small fraction of natural aggregate, make possible the construction of low height buildings. The application of the recycled small fraction, in the preparation of foundation and revetment mortar, shows efficient employed with the set masonry-mortar. The aggregate characterization, the study of the proportion of ingredients for concrete, the analysis of the physical and mechanical performance of the blocks, prisms and walls of structural masonry, as well the correlations of efficiency and analysis of the influence of foundation and revetment mortar, relating to the resistence of adherence to traction, are necessities for the knowledge and utilization of this material

The object of this Master`s thesis is the river training of the Luha river in Jeseník nad Odrou. The thesis is divided into several chapters. In the theoretical introduction, the problems of the sediment flow regime are discussed. Moreover, it deals with the questions associated with the roughness in open channels and adjustment of riparian zones. As a part of the overall proposal of the flow adjustment, the hydraulically most suitable cross section in cunette is proposed. It is done with respect to the desired velocity ratios in the profile. Since the new cunette shape was established, the adjustment of vertical alignment was proposed. The thesis also contains the capacity assessment of the existing channel. Design of adjustment of flood protection measures includes mainly spatial rearrangement and increase the crest of levees with respect to the local conditions. The thesis also suggests the placement of vegetation in the riparian zones. Furhermore, the work deals with problems arising from the flow adjustment considering applicable laws and regulations of the Czech Republic. In the case of project implementation, it is necessary to evaluate these problems independently.

No description available.

An erosion control revetment was constructed at the Falkner Island Unit of the Stewart B. McKinney National Wildlife Refuge, Connecticut during the winter of 2000–2001. At the time, Falkner Island was the fifth largest breeding colony site for the federally endangered Roseate Tern. This study measures and describes some baseline information regarding Roseate Tern nesting, behavior, and habitat use at Falkner Island during the three breeding seasons prior to revetment construction (1998–2000). This baseline information is then compared to similar information from the first breeding season following revetment construction (2001). For Roseate Tern adults, this study examined changes in pre-nesting habitat use, nest site distributions, and pre-nesting behavioral time allocation. Changes in habitat availability and habitat use by Roseate Terns are compared as a result of the revetment construction. Roseate Terns used rocky beach in a greater proportion than other habitats before revetment construction, and used revetment boulders in a greater proportion than all other habitats after revetment construction. Roseate Terns nested more often in artificial sites (nest boxes and tires) than in natural sites in all years of the study. The mean date for the first eggs in each nest did not differ between years. We observed more Roseate Terns prospecting artificial nest sites (n = 66 times) than natural sites (n = 21 times) for three years of this study. Prospecting behavior occurred later in the season in some subcolonies, but this difference did not appear to be related to the construction. For Roseate Tern chicks, this study investigated the use of crevices as hiding places from before (1999–2000) and after (2001) the construction of an erosion control revetment. In all years, Roseate Tern chicks used crevices found under artificial nest sites more frequently than expected by chance when compared to crevices found in other microhabitats. Chicks also used crevices formed in various microhabitat types at different stages of development. The erosion control revetment created crevices that had larger openings, steeper floors, and deeper lengths than those previously used by chicks before construction. In the year after revetment construction, the openings of crevices used by chicks that died were wider than crevices used by chicks that survived. We discuss our findings in the context of the potential consequences that the revetment construction had on Roseate Tern chick survival.