Fabrício Jaques Sutili

PROTEÇÃO FÍSICO-MECÂNICA DA BASE DE UMA ENCOSTA NA MARGEM DO RIO URUGUAI COM ENROCAMENTO VIVO

With the occurrence of intense rainfall phenomena, the surplus water volume in reservoirs of hydropower plants needs to be drained, which usually implies in spillage of large stream discharge that can compromise the stability of slopes and hillsides downstream of the spillway. Appropriate technical solutions should therefore be used to minimize soil losses and damage to flora and fauna. One suitable technique for streambanks protection is the live rip-rap. The aim of this work is to describe the execution of a live rip-rap carried out in a section of the left bank of the Uruguay river downstream of the UHE Itá dam, from a brief design characterization to the results achieved two years after its execution. The monitoring of the work for qualitative analysis of the structures behavior and the development of the plants was regularly done. Shrub and tree data were collected through the implantation of 6 permanent plots of 10,0 m in length and 1,7 m in height (17 m2). The first measurement campaign was carried out immediately after the execution of the work and the second after 24 months. The results obtained with this work confirm that live rip-rap is efficiently fulfilling with the mechanical protection of the slope two years after the intervention, no physical damage was observed in the structure and that vegetation is in full development and are contributing to increase stability of the structure through its root systems and canopies.

AVALIAÇÃO DA PROPAGAÇÃO VEGETATIVA DE ESPÉCIES UTILIZADAS NA ESTABILIZAÇÃO DE OBRAS DE TERRA COM TÉCNICAS DE ENGENHARIA NATURAL

Soil bioengineering techniques use live construction materials like plants and live cuttings as well as inert materials as structural elements in simple constructions, with the purpose of ecological restoration and soil stabilization. The inert materials used depend on the aims and the local availability, are essentially metal structures, geotextiles, timber, stones or even concrete. These, in addition to provide immediate soil stabilization also supply protection and support for the further development of the vegetation. The vegetative part complements, gradually or entirely, replaces the functions of stabilizing inert components. However, construction works, can only be performed successfully when the vegetation technical characteristics are known and, thus, properly exploited. This research is the result of a sequence of experiments performed with the goal of identifying, among riparian inhabit species, those with vegetative propagation capacity and development. A large part of soil bioengineering models use exclusively that way of propagation. Among the many potentially influential factors in vegetative development, such as survival, rooting and sprouting rate, growth roots and shoots velocity, should be also highlighted, the importance of collecting and planting time for vegetation. Therefore, this study, using experimental plots built in different times of the year, seeks to obtain this information by assessing the survival rate, shoots and roots development using cuttings of six potential species easily found along stream banks in southern Brazil rivers. The tested species are: Calliandra brevipes , Phyllanthus sellowianus , Pouteria salicifolia , Salix humboldtiana , Salix x rubens and Sebastiania schottiana . The experimental results indicate the possibility of using some of these species. Calliandra brevipes , Sebastiania schottiana and Pouteria salicifolia presented lower development than Phyllanthus sellowianus , Salix humboldtiana and Salix x rubens . It was evidenced that the planting season, is less important in species with fast rooting, as Phyllanthus sellowianus , Salix humboldtiana and Salix x rubens , but can be decisive in species with slower rooting, such as Sebastiania schottiana , and can even have an effect on the survival rate of these species.

Anatomia da madeira de Aspidosperma riedelii Müll. Arg. (Apocynaceae)

O lenho de Aspidosperma riedelii e anatomicamente descrito e ilustrado com fotomicrografias. Na estrutura anatomica destacam-se: porosidade difusa; vasos solitarios; poros de diâmetro muito pequeno e com paredes finas; parenquima apotraqueal; raios estreitos, em sua maioria unisseriados; e fibras pouco lignificadas. Com excecao dos dois primeiros caracteres, que tem ampla ocorrencia no genero em estudo, os demais agregam flexibilidade a ramos e caules e, sendo comuns em reofitas, confirmam a especie como promissora para utilizacao em obras de engenharia natural e recuperacao de areas degradadas, em margens de cursos de agua.