Responsible Development in Tulum, Mexico: Considering Water Quality and Subaqueous Cave Locations

Abstract

Development is rapidly occurring along the Mayan Riviera in the Yucatan Peninsula, Mexico with little regard to environmental regulations or wellbeing. In particular, fresh water must be considered when planning for future development. The sole source of fresh water in the Yucatan is from a karstic aquifer that is characterized by an extensive network of subaqueous caves, a system that is particularly sensitive to contamination. This master’s project focuses on the current and future water supply for the town of Tulum since the town’s future development will have long term repercussions on the surrounding environment. Water samples collected around Tulum in the summer of 2008 were analyzed to determine the current water quality of wells and cenotes (sinkholes). Cave survey data that was collected by cave divers and the Quintana Roo Speleological Survey was used to create a map of the known cave systems. Satellite imagery was classified to determine the current land use/ land cover of the area and the extent of future development was estimated according to the Urban Development Plan (UDP) of Tulum.

Water quality results show that nitrate contamination is within acceptable limits according to Mexican water standards. These results would likely be very different if the samples had been taken during the dry season when nitrate contamination is more concentrated. Chloride and sodium concentrations are well above Mexican water standards; the water supply that the city of Tulum relies upon is already experiencing salinization. It is likely that higher future withdrawals from this water source will be increasingly more saline, which may necessitate a different freshwater source for the city. Mapping of the known subaqueous caves shows that the vast majority of the network (81%) is overlaid by forest and is therefore less likely to be contaminated from the surface. Future development according to the UDP of Tulum will occur above a substantial area of subterranean caves. To protect water quality, the UDP should be altered to take cave locations into consideration. High impact development should be resituated and land above the cave systems should be zoned for limited, if any, development.