What is an estuary?

Estuaries are places where rivers meet the sea, an ecotone where two distinct bodies of water meet, mix, and support a broad array of species and habitats.  Estuaries are also places where humans tend to dominate the landscape:  when settlers and travelers first arrived on the Oregon Coast, estuaries provided safe harbors from storms, vast food supplies, acted as transportation corridors, and presented a gateway into the terrestrial system rich with resources.  However, after decades of use and abuse, estuarine systems are some of the most impacted and degraded habitats.  Estuaries are at the bottom of watershed drainage basins, receiving anthropogenic impacts such as altered, infrequent, and intense water flows, increased chemical and particulate pollutants, dense aquaculture, non-native invasive species, overfishing, habitat modification and/or elimination, stream and marsh channelization, and the conversion of lands for agricultural, commercial, or urban use.  In recent years, there has been a growing interest in the preservation, conservation, and restoration of estuarine systems to improve habitat integrity and support sustainable anthropogenic use, often under the guise of restoring the endangered Pacific Salmon.  Governments, agencies, interest/community groups, and concerned individuals are all stakeholders in estuarine restoration within the Pacific Northwest.

The process of restoration is very detailed, and for a successful project to take place, many components, stakeholders, and options must be assessed.  Steps include:  taking inventory of the current habitat and species, analyzing available tools and resources for the project (social, economic, and natural capital), prioritizing projects, performing the physical restoration itself, monitoring restoration progress, comparing the project to pre-selected reference sites, and examining whether physical processes have been established and can continue without human intervention.  These and other concepts are imperative for expanding upon the basic ecological understanding of the estuarine system to be restored and for utilizing an adaptive management approach.  Geographic Information Systems (GIS) provide unique resources for practitioners in their planning, assessment, monitoring, and modeling of restoration projects, particularly for estuaries.  For example, not all areas of an estuary are accessible on foot or by boat, tides present a challenge for monitoring and modeling.  It is important to remember that fundamentally, estuaries are dynamic systems, as the water flow and composition is constantly changing.  For more information on the monitoring of estuaries, water quality, and restoration, investigate the following links: 

Estuarine Monitoring using GIS

Water Quality Monitoring using GIS

Restoration Monitoring using GIS