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The 3D mapping of Casa de Pedra emerged during the master’s research of Vanessa Faria Bohrer at USP’s Institute of Geosciences (IGc), under the supervision of Strikis. In her study, Vanessa measures the discharge of the river spring that flows through the cave, monitoring flood waves within Casa de Pedra.

“There has been a speleological management plan for this cave since 2010, but hydrological monitoring was still lacking for park authorities to evaluate a possible reopening”, explained the master’s student, who periodically shares fieldwork updates on the Projeto Casa de Pedra Instagram page. Vanessa highlights the challenges involved in the research, with field collections conducted every 2 months and requiring extensive planning due to the imminent risk of flooding.

“It is demanding fieldwork, a 3-hour hike to reach the portal, but extremely rewarding. We have always believed in the project’s impact on society, both for local tourism and nationally and internationally”, she says. In addition to relying on weather forecasts, Vanessa and Strikis receive support from hydrologists at the Environmental Research Institute (IPA) and members of the Civil Defense of Iporanga during data collection. The work involves 4 days of dedication: the first for travel to Iporanga; the second for planning the trip to the resurgence point, where the underground waters of the Maximiano River re-emerge inside the cave. The third for data collection at the portal; and the fourth for recording precipitation data at the river’s headwaters in the Caboclos sector, in the center of the park.

According to Strikis, Casa de Pedra is an important heritage site for which no historical measurement records exist. “In addition to generating unprecedented scientific results, this study could also support the management of public policies in the area”, he states. Although there is the possibility of reopening the cave for visitation, the researcher stresses that it is a highly challenging environment requiring extensive experience in subterranean settings. “It is as if you were walking through collapsed ruins, with the river flowing and several sections without escape areas. It is technical. It is not conventional tourism. I would not recommend it casually”,  he concludes.

Research data still under processing indicate the occurrence of flood episodes marked by significant rises in water levels at the river’s resurgence area inside the cave. Rainfall of 60 millimeters per hour (mm/h) resulted in a 2.17-meter increase at the beginning of last year; records from December showed that rainfall of 50 mm/h caused the water level to reach 1.90 meters in the same chamber. Less intense rainfall, at 10 mm/h , was also sufficient for the river to rise to 1 meter in the resurgence area.

“The time interval between the peak rainfall and the peak water level was approximately 1.5 hours. In other words, it was quite fast, though not instantaneous – there would still be time for evacuation”, Vanessa explains. She emphasizes that the data are still being analyzed using different methods to determine factors such as the average time for water level rise under varying rainfall intensities, as well as the average recession time – the time required for the river to return to what is considered its normal level.