Hydrological Resources: An Ecosystem Based Approach for Coastal Management

Ashby, S. (2014). Hydrological Resources: An Ecosystem Based Approach for Coastal Management. Instituto Politecnico Nacional IPN-Israel Water Week. Mexico City, Mexico.

Abstract Coastal areas are complex systems with unique habitats, recreational opportunities, economic activities, and highly urbanized areas. In 1997, Costanza et al. reported that coastal habitats, such as those found in estuarine ecosystems, are valued at providing an estimated US14$ trillion worth of ecosystem goods and services annually, or 43% of the global total. Coastal areas are also the downstream area of a watershed that also is a complex system. Both coastal systems and watershed activities provide multiple services to society. Often these services are impacted by water management decisions. For example, recent studies of some coastal systems indicated that major stressors were primarily from hydrologic modifications and urbanization. Additionally, upstream management for water supply, flood damage reduction, and navigation all impact hydrologic regimes. Hydrologic modifications impact the quantity, quality, and timing of freshwater inflows that are critical to coastal habitats. For example, decreased freshwater flows will increase the salinity in an estuary and great alter the habitat quality. For non-mobile organisms such as oysters, this could greatly impact the local fishery and commercial harvest. Even mobile marine species (e.g., crabs and shrimp) utilize estuaries during their life cycles and require a variety of salinity gradients at critical times. Consequently, water resource management decisions that impact these services that need to be balanced among societal needs. Management decisions need to be based on input from all aspects of society (e.g., citizens, politicians, industry, scientists, and managers. Ecosystem based management incorporates sustainability, ecosystem health and quality of life (Arkema et al., 2006) and provides a framework to achieve this balance. Representative conceptual models and frameworks for ecosystem based management for coastal systems will be presented.