Biorolls are cylindrical structures composed of a bag sisal and coconut + polypropylene mesh multifilament with high strength to the action of water, very compact, 30, 40 and 50 cm in diameter and 3m or 6m longitude.
They are used primarily for the protection of borders and beds such as “faixinhas”, also in the restoration of embankments, recommended for those areas subjected to a high or very high erosion (flow velocity of water exceeding 1.5 m/s or 2,5 m/s and higher pending ½ and 1/3). In this type of structures, plants with a well developed root system as aquatic ones, play a fundamental role in the results of the restoration because these structures, with appropriate designed plants, should be grown in nurseries, in order to provide them maximum accurancy.
It is normally used for holding and retaining pellets. Should always be used in the cross slope of the embankment, set with sharp stakes, made out of wood or steel. Can be reconciled with the planting os grass type Vetiver (Vetiver zizanioides).
Similar to “peigne” technique however, using cylinders from 10 to 30 cm diameter, is used to control erosion on the foot of slopes where the flow velocity is not too high. The bio-rolls degrades after a period of two to five years, but the seeds that are inside promote revegetation that will produce the final stabilization by the root system while the bio-rolls degrades. Are usually associated with other techniques for revegetation at the upper margins parts, such as fascines, stakes, etc.
After the first rains, inspections should be made to verify whether the bio-rolls are in the position they were installed. In addition, regular inspections should be made during the first few months, when vegetation growth occurs and is required replanting of vegetation that has not been developed in the top part of the slope.
After the establishment of the vegetation and degradation of the bio-rolls, inspections should be made to verify that the root growth of vegetation was sufficient to stabilize the bank.