Avaliação de eficiência da implantação de técnica de bioengenharia de solos

O Baixo São Francisco está em constante dinâmica hidroambiental resultante das alterações promovidas na calha do rio, representadas pelos processos geomorfológicos ou por ações antrópicas como a construção das barragens que por sua vez provocou mudanças geomorfológicas resultando na aceleração de processos erosivos nas suas margens. O objetivo deste trabalho foi avaliar a implantação de técnicas de recuperação hidroambiental com uso de bioengenharia de solos na margem do rio São Francisco. A área estudada compreende um trecho do baixo curso do rio São Francisco, localizado no município de Amparo do São Francisco, no estado de Sergipe, nordeste do Brasil, onde técnica de bioengenharia de solos, como enrocamento vegetado, foi implementada no ano de 2011. Três grupos de indicadores individuais foram selecionados que juntos contribuíram para a avaliação da Recuperação da Área Degradada relacionados à qualidade do solo, como resistência do solo à penetração e Velocidade de Infiltração Básica, à recuperação da biodiversidade como banco de sementes e a regeneração natural da área por meio de indicadores como composição e cobertura linear de espécies. A metodologia empregada contempla uma avaliação dos resultados originados do uso da biotécnica a partir da identificação da contribuição da vegetação que auxilia na contenção de taludes, uma vez que a cobertura vegetal protege a superfície do solo contra ações erosivas como o vento e a água da chuva. O reforço mecânico trazido pelo sistema radicular das plantas contra cisalhamento do solo se mostrou pela menor resistência à penetração do solo e maior Taxa de infiltração. Evaluation of efficiency of the implementation of soil bioengineering techniqueA B S T R A C TThe Lower São Francisco is in constant hydro-environmental dynamics resulting from the changes promoted in the river channel, represented by geomorphological processes or by anthropic actions such as the construction of dams that in turn caused geomorphological changes resulting in the acceleration of erosive processes on its banks. The objective of this work was to evaluate the implementation of hydroenvironmental recovery techniques using soil bioengineering on the bank of the São Francisco River. The studied area comprises a stretch of the low course of the São Francisco River, located in the municipality of Amparo do São Francisco, in the state of Sergipe, northeastearn Brazil, where soil bioengineering technique, such as vegetated rockfill, was implemented in 2011. Three groups of individual indicators were selected that together contributed to the assessment of Degraded Area Recovery related to soil quality, such as soil resistance to penetration and Basic Infiltration Speed, to the recovery of biodiversity as a seed bank and the natural area regeneration through indicators such as composition and linear species coverage. The employed methodology includes an evaluation of the results from the use of biotechnology based on the identification of the vegetation contribution that helps to contain slopes, since the vegetation cover protects the soil surface against erosive actions such as wind and rainwater. The mechanical reinforcement brought by the root system against soil shear was shown by the lower resistance to soil penetration and a higher infiltration rate.Keywords: Degraded Areas Recovery, erosion, São Francisco River

Soil bioengineering for sustainable coffee farming in Way Besai sub-watersheds, Lampung, Indonesia

Soil bioengineering is part of vegetative land conservation activities, including covering all use of plants to maintain the carrying capacity of the land. The sustainability of coffee farming achievement in the upstream watershed area is closely related to the application of soil bioengineering technology. This study conducted to identify the recent studies of soil bioengineering technology and its application in coffee farming toward increasing the land productivity in the upstream watershed. The research location is a smallholder coffee plantation upstream of the Way Besay sub-watershed, spread over 3 sub-districts, Air Hitam, Way Tenong, and Sumber Jaya sub-District, West Lampung, Lampung, Indonesia. Coffee farmers as many as 167 people as respondents. The data analysis method used exploration of the applicability of soil bioengineering technology at the micro-level. The mapping of the role of soil bioengineering trace using the VosViewer tool. The results of the analysis show that the readiness level application of soil bioengineering technology in coffee farming includes the production and use of organic fertilizers made from local materials, the use of mulch as soil cover, agroforestry with a variety of tall canopy plants/MPTS, the planting of multiple cropping (planting various yielding crops), and plant diversification with alley planting. Soil bioengineering technology has a very high potential to increase land productivity to support sustainable coffee production in the upstream area of the Lampung watershed.

Bioengineering and Hydromechanics of Flora in Stabilization of Slopes

This paper focusses on the hydromechanics of flora in the stabilization of soils. Slopes in rocks and soils are founding in physical and manmade conditions. Stockpiles, canals, levee, dams and highways are structured through the slopping of lateral faces in soils since a slope is typically cost effective compared to structuring walls. Physical forces e.g. water and winds transform the earth’s topography and other planets, typically forming unstabilized slopes. Flora is considered one of the initiatives considered in the control and prevention of landslides that are shallow and ones occurring during rainy seasons. Vegetation application for the stabilization of slopes is identified as soil bioengineering. Knowledge of flora contribution, in this paper, will be reflected on a case area of Kedah (Northwestern part of Peninsular Malaysia). The aspect of bioengineering i.e. mechanical and hydrological aspects will be applied. The effects of hydromechanical of flora on the stability of slopes are to minimize the content of soil water through evapotranspiration, interception and transpiration. Mechanical implication of flora on slope stabilization is to stabilize slopes to reinforce it mechanically.

Soil bioengineering in northeastern Brazil: An Overview

This article presents an overview of the application of soil bioengineering techniques, also modeled as natural engineering, in the state of Sergipe, northeastern Brazil, showing the importance of integrating living and inert elements to protect river banks from erosion. The employed techniques are different, ranging from the characterization of susceptibility to erosion to the use of biotechniques, considering knowledge in the areas of agronomic engineering, forestry engineering, civil engineering, biology, pedology, geology, geomorphology and geotechnics. It is an approach that uses techniques and methodologies in a multidisciplinary way, seeking to maximize synergies (for example, natural engineering techniques to combine inert materials in ways that help plants to develop increasingly efficient systems). This approach also considers maintenance-cost optimization in the conduction of the works, using different materials, differing from traditional engineering, which uses predominantly inert materials. The research work carried out in different locations sought the availability of local materials such as rocks, geotextiles made from fibers from the native flora or even available on the market, in addition to the use of native species to recovery of the banks or slopes, according to the ecological conditions of the northeastern Brazil. Size and technological and ecological reach were also considered, in addition to different biotechnical aesthetic objectives adapted to different situations.

Sediment input from the São Francisco River bank, Northeast Brazil, under low discharge period

The objective of this study was to evaluate the input of suspended sediment from the slope toe in the São Francisco River channel, in Northeast Brazil, under different soil bioengineering techniques. Sediments were collected in the years of 2013, 2014 and 2015, in five transects crossing the river channel. Sediment input in the sampling points was higher in the year of 2013, i.e., the year of the highest river discharge. Sediment supply to the river channel for a period of 3 years (2013, 2014 and 2015), was evaluated at 20, 40 and 60% depth, along five different transects (P1= riverbank, P2= beginning of the thalweg, P3= middle of the thalweg, P4= end of the thalweg, and P5 = margin of the side sandybar), oriented by the presence or absence of erosion control techniques (treatments) such as: 1-Natural Vegetated Slope; 2-Vegetated Riprap; 3-Eroded Slope; 4-Live Cribwall and 5-Vetiver grass Contour Line. Sediments input was different in all evaluated transects, and the one identified as Eroded Slope at 20% depth presented the lowest amount of suspended sediment load. There was a decrease in the total amount of suspended sediment in the evaluated periods, probably due to the progressive decrease in the river discharge, and the protection provided by the soil bioengineering techniques.