Addressing the Challenge: Improving Methods for the Mitigation of Environmental and Biodiversity Impacts on 3D Seismic Survey in Tropical Forests

Abstract

For more than twenty years, Seismic surveys have been changing both in the incorporation of environmental and biodiversity criteria as well as in its implementation and performance indicators. The 3D seismic survey in the block 57 located in the tropical Andes, lower basin of the Urubamba river, has incorporated new techniques to minimize direct, secondary and cumulative impacts, focusing on each phase of the exploratory project. The technology used for data acquisition was made through the Geospace Seismic Recorder (GSX), which is a cableless seismic acquisition system that does not need a white house in seismic lines. This made possible the reduction of flying hours to transport materials, as well as a lower fuel consumption and clearing areas of flying camps and drop zones. The effluent treatment was one of the greatest challenges, due to the environmental standards set for dumping. In the base camp, additionally to the implementation of a wastewater treatment plant(conventionally used in other projects), it was necessary to complement it with previous processes by the use of equalization tanks and with subsequent processes using sedimentation cameras, flocculation and high rate filtration. During the topography and advanced studies, each group was assistedwith specialized personnel for the identification of Biologically Sensitive Areas (BSA) as well as forest survey prior to deforestation. In spite of the difficulty of the terrain and the predominance of the bamboo (Guadua spp.), seismic lines had a maximum width of 1.5 meters andrespected trees of more than 10 cm DBH. Biologically Sensitive Areas (BSA) were identified and avoided in the flying camps, heliports, seismics lines and drop zones. Abandonment activities considered primarily the natural regeneration of the forest. Residual wood from deforestation and flying camps were chopped on average of 0.3 × 0.45 × 0.20 meters in order to promote its decomposition. In addition, compacted soil was loosed on the areas intervened. The use of similar species that were reported in the forestry survey was also considered. For this purpose a greenhouse with 230 seedlings on average was installed in each camp from the beginning until the abandonment, and certified seed of native forest species: Amasisa (Erythrina ulei), Huairuro (Ormosia coccinea), Pachaco (Parkia multijuga), Bolaina (Guazuma crinita) Copaiba (Copaifera paupera) was also used. In the case of drop zones located in lines nearby, samples were used to the area.