Assessing coastal management plans using watershed spatial models for the Mississippi delta, USA, and the Ususmacinta–Grijalva delta, Mexico

Holistic performance measures for coastal restoration are needed as management alternatives are implemented in the Gulf of Mexico. Regional questions can be addressed with watershed models using large-scale spatial dynamics to examine environmental impacts. Two watershed models investigated habitat shifts in the largest deltas of the Gulf of Mexico. One model varied river forcing scenarios in the Mississippi delta, USA, an area with restricted freshwater inputs. The other model investigated the Centla swamps, part of the Usumacinta–Grijalva delta in Mexico, a region with unrestricted freshwater inputs. Wetland conversion to open water and yearly shifts of marsh habitats in these two contrasting watersheds were assessed. Models forecasted effects of industrial development and river diversion management plans for 10 and 50 years. Results indicated that healthy functioning of both deltas depended largely on river-borne contributions. Watershed models can provide natural resource managers, decision makers with a scientific instrument for environmental policy.