Puerto Rico has always been a wet place, though not always in the same way. The older geological record—volcanic spines split by ancient forces, steep basins that empty fast, coastal plains built from thousands of years of river sediment—set the island’s natural rhythm. Water ran where the land allowed it. Mangroves stitched the low edges. Floodplains behaved as floodplains.
Aydasara Ortega Torres
The historical record tells a different story, one that begins when engineers, surveyors, and administrators started asking the land to behave otherwise. In the early and mid-twentieth century, a series of projects reworked the island in fragments: a river straightened here, a wetland drained there, a coastal fill to gain a few more acres of land, slopes cut for new roads that didn’t quite follow the contours. Each intervention made sense within its own context; none were expected to accumulate into the system we see today.
Land-use research describes this pattern as a slow build-up, where small decisions eventually shift the entire structure (Cieślak & Biłozor, 2021). Puerto Rico fits that description cleanly. Not because planners intended harm, but because the terrain was altered in pieces, across decades, and the consequences settled quietly until storms made them visible.
The technical language of vulnerability organizes risk into three components—exposure, sensitivity, and adaptive capacity (Gaughan et al., 2019)—but these categories blur once you look at the island historically. Exposure is the shape of the land and the shape imposed on it: redirected streams, reclaimed coastlines, floodplains compressed under new neighborhoods. Sensitivity appears in the soil itself; some areas were compacted so repeatedly that they lost the ability to absorb water, while others once meant to hold overflow are now paved or built. And whatever we call adaptive capacity reflects a long chain of uneven improvements. Some sectors received updated systems, while others waited years or decades.
Recent work mapping flood risk shows how these layers still dictate outcomes. Many of the homes most vulnerable today stand on terrain reshaped in earlier waves of development—old fills, adjusted channels, or reworked coastal deposits (Diaz et al., 2024). Flooding now is not only meteorological; it is historical.
After a heavy rain, you can read this past without opening a single archive. Water gathers in the same depressions year after year. Streets built across former wetlands soften at the edges. In the mountains, runoff accelerates over slopes that lost vegetation long before any current resident moved in. And in metropolitan zones, stormwater systems struggle with rainfall intensities they were never designed to handle. The differences between neighborhoods are striking, and they line up with decades of uneven public investment and shifting priorities across the island (West, 2023).
Looking at these layers—geological and administrative—has little to do with nostalgia or judgment. It is simply the only way to understand why the terrain behaves as it does now.
When storms arrive, they meet two versions of Puerto Rico: the geological one shaped over millions of years, and the political one assembled over the last century. The interaction between those histories gives the island its present condition—still wet, but for reasons that reach far beyond climate.
Recognizing this intertwined past is not an academic exercise. It is a practical requirement. Without acknowledging the depth of these layers, new interventions risk repeating the same patterns. The land has absorbed more than rain; it has absorbed decisions, and it holds them with the persistence of saturated soil.
References
Cieślak, I., & Biłozor, A. (2021). An analysis of an area’s vulnerability to the emergence of land-use conflicts. Land, 10(11), 1173. https://doi.org/10.3390/land10111173
Diaz, N. D., Lee, Y., Kothuis, B. L. M., Pagán-Trinidad, I., Jonkman, S. N., & Brody, S. D. (2024). Mapping the flood vulnerability of residential structures: Cases from The Netherlands, Puerto Rico, and the United States. Geosciences, 14(4), 109. https://www.mdpi.com/2076-3263/14/4/109
Gaughan, A. E., Stevens, F. R., Pricope, N. G., Hartter, J., Cassidy, L., & Salerno, J. (2019). Operationalizing vulnerability: Land system dynamics in a transfrontier conservation area. Land, 8(7), 111. https://doi.org/10.3390/land8070111
West, J. (2023). Social vulnerability and population loss in Puerto Rico after Hurricane María. Population and Environment, 45(2). https://doi.org/10.1007/s11111-023-00418-3