Nonlinear Response of Pacific Northwest Estuaries to Changing Hydroclimatic Conditions: Flood Frequency, Recovery Time and Resilience

EPA Grant Number: R833015
Title: Nonlinear Response of Pacific Northwest Estuaries to Changing Hydroclimatic Conditions: Flood Frequency, Recovery Time and Resilience
Investigators: D'Andrea, Anthony F. , Wheatcroft, Robert A.
Current Investigators: Wheatcroft, Robert A. , D'Andrea, Anthony F.
Institution: Oregon State University
EPA Project Officer: Packard, Benjamin H
Project Period: July 1, 2006 through June 30, 2010
Project Amount: $620,182
RFA: Nonlinear Responses to Global Change in Linked Aquatic and Terrestrial Ecosystems and Effects of Multiple Factors on Terrestrial Ecosystems: A Joint Research Solicitation- EPA, DOE (2005) RFA Text |  Recipients Lists
Research Category: Global Climate Change , Ecosystems , Climate Change


The frequency of intense precipitation events is increasing in the US and the risk of extreme floods is forecasted to increase nonlinearly with modest climate shifts. Pacific Northwest (PNW) estuaries are at particular risk due to their strongly seasonal rainfall pattern and increased sediment load during discharge events. Rapid deposition of fine-grained sediment during floods may lead to abrupt changes in the structure and function of sand flat benthic communities and facilitate colonization by non-indigenous species. The main objectives of this research are to quantify the resilience of benthic communities to flood sedimentation events and identify the ramifications of such resilience to the health and ecosystem services provided by PNW estuaries.


We propose a manipulative field study simulating different frequencies of flood sedimentation events (no, one, or two events in a single rain season) that subsequently tracks the recovery of the benthic community from these events using a combination of high-resolution benthic sampling and multivariate analyses of benthic community metrics. Particular emphasis will be placed on identifying changes in functional biodiversity, documenting recovery times and potential hysteresis effects of multiple flood sedimentation events, tracking mortality and recovery of important functional groups, and identifying changes to the populations of native and non-indigenous species. Parallel sediment samples will be collected and analyzed to quantify changes in important physical and biogeochemical sediment properties that have direct or indirect effects on survival or habitat suitability for the benthic community.

Expected Results:

This study will develop an empirical and theoretical framework for predicting the effects of flood sedimentation events on sand flat macrobenthic communities in PNW estuaries and how these changes impact ecologically and economically important biotic resources and ecosystem services. This study will be used to quantify the resilience of intertidal benthic communities and identify important structural changes that may indicate a threshold or catastrophic shift in the benthic ecosystem in response to increasingly frequent sedimentation events. Since neither sufficient data nor models currently exist to conduct risk analyses, these datasets will significantly improve our ability to perform ecorisk assessments in PNW estuaries. In addition, the information obtained in this study can be used by watershed and coastal resource managers to make better-informed decisions regarding actions (e.g. restoration) to minimize or eliminate the risks to these systems.

Publications and Presentations:

Publications have been submitted on this project: View all 4 publications for this project

Supplemental Keywords:

EPA Region 10, Ecosystems, global climate change, Oregon (OR), Pacific coast, Pacific northwest, Ecosystem Protection/Environmental Exposure & Risk, RFA, Aquatic Ecosystem, Aquatic Ecosystems & Estuarine Research, Ecological Risk Assessment, Ecology and Ecosystems, Environmental Monitoring, climate change, climate, climatic influence, coastal ecosystems, ecosystem indicators, ecosystem stress, environmental measurement, environmental stress, estuaries, global change, marine science, biology, ecology, benthos,, RFA, Scientific Discipline, Air, Ecosystem Protection/Environmental Exposure & Risk, Hydrology, climate change, Air Pollution Effects, Monitoring/Modeling, Regional/Scaling, Environmental Monitoring, Ecological Risk Assessment, Atmosphere, coastal ecosystem, biodiversity, ecosystem assessment, environmental measurement, meteorology, global change, anthropogenic, greenhouse gases, climate models, UV radiation, environmental stress, water quality, coastal ecosystems, climate model, ecological models, flood trends, atmospheric chemistry, climate variability, Global Climate Change, land use, regional anthropogenic stresses

Relevant Websites:

Nonlinear Response of Pacific Northwest Estuaries to Changing Hydroclimatic Conditions:  Flood Frequency, Recovery Time, and Resilience (PDF) (1 pp, 32 K)

Progress and Final Reports:

  • 2007 Progress Report
  • 2008 Progress Report
  • 2009 Progress Report
  • Final Report