This is a reformatted edition of the authors' joint 2006 M.Sc. thesis at the
Technical University of Denmark. Abstract:
Urban, industrial and agricultural activities threaten the groundwater resource that feeds the Sian
Ka'an Biosphere Reserve, a UNESCO World Heritage site on the Caribbean coast of the
Yucatan Peninsula, Mexico. The area has a complex karstic geology with high permeability
features, and the thesis investigates how the water resource dynamics of the catchment that
encompasses the Reserve can best be modelled. A conduit-matrix model has been found to be
appropriate for modelling groundwater flow in the catchment on a local scale, whereas an
equivalent porous medium model is appropriate for regional scale modelling. High permeability
zones have been identified based on visual inspection of satellite imagery and confirmed using
frequency-domain geophysical measurements. These zones have been incorporated into the
model scenarios and have been found to significantly impact the size of the catchment. The
regional hydrological modelling has shown that a significant potential threat to the Reserve is
posed by the nearby urban and agricultural areas of Felipe Carrillo Puerto and Andres Quintana
Roo, from where pollutants may be able to reach the Reserve in less than 10 years. Also pollution
from more distant areas may be able to reach the Reserve assuming high permeability in the
identified structures. Moreover, it cannot be excluded that pollution from the area covered by the
proposed development plan for Tulum can spread to the Reserve. The visual outcomes of the
hydrological models is expected to be valuable inputs to decision making processes concerning
the management of the groundwater resources of the Sian Ka'an catchment in the future.
