Environmental Test of Quality of Bank Revetment on the Pirai River, in Bolivia, 33 Years after Construction and Comparison with the Natural Bank

The present work presents the test of the protection of the embankment built thirty-five years ago to protect the city of Santa Cruz de la Sierra which, in 1983, was flooded during an extraordinary flood of the Rio Piraí, caused by heavy rains caused by the El Niño.

An initial test has already been carried out, showing the landscape integration of the embankment revetment after several decades of its construction.

In the last quarter of 2018 it began the first part of the program involves the collection of historical, topographic and hydraulic data available and on-site collection of the necessary elements for an environmental assessment of the areas identified on the Reno mattresses lining and the natural banks; the second part of the program will be implemented in the first quarter of 2019 and will consist in identifying the areas to be examined and assessing the environmental quality of the different areas that will be compared to each other.

The data collected refer to the topography and hydraulic conditions of the river in the examined area and belonging to the Searpi archive (SErvicio Autonomo de Regularización del Río Pirai).

The selected areas are located: thr first in a stretch of the lining built in 1985, the second in a stretch built in 1995, the third in a stretch on the same natural bank about 500 upstream (where the effect of the presence of the coating is not affected ) and the last on the opposite bank also natural.

For the collection of data, a specially prepared sheet was used which, in the course of 2019, will also be used in other river works in some Latin American countries to standardize the results and create a database on the expected behavior of human interventions in watercourses in relation to different types of structure, natural environments, hydraulic conditions.

The test will be used to calibrate the card so that, in the future, it can be used to make a first objective assessment of the variation of the environmental quality between the artificial protection and the natural bank or in the passage of time, in order to predict the behavior of a structure built by man in a watercourse.