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VELMA Modeling to Predict Effects of Environmental Change on the Flows and Water Quality of the Trask River (Presentation)
Citation:
Marois, D., T. Dewitt, AND R. McKane. VELMA Modeling to Predict Effects of Environmental Change on the Flows and Water Quality of the Trask River (Presentation). webinar, OR, Newport, May 09, 2019.
Impact/Purpose:
Coastal watersheds provide valuable ecosystem goods and services to coastal communities including forest materials, drinking water, fish habitat, and recreation. How these watersheds are managed controls the balance between the delivery of these various goods and services. The model, VELMA (Visualizing Ecosystem Land Management Assessments), has numerous applications related to watershed management and can set an example for science-based decision making. The US Forest Service, Oregon Department of Forestry and their collaborators are interested in how VELMA can help make their watershed studies have a broader applicability and provide future predictions of water quantity and quality flowing from coastal rivers. This presentation is an update to these groups on the state of our modeling work in the Trask Watershed.
Description:
We used the ecohydrology model, VELMA, in the Trask River watershed to simulate the effects of environmental change scenarios on estuarine river inputs to the Tillamook Bay (Oregon) estuary. The Trask River watershed is 453 km2 and contains extensive agriculture, silviculture, urban, and wetland areas. VELMA was parameterized using existing spatial datasets of elevation, soil type, land use, air temperature, precipitation and river flow. Water quality samples were gathered in the lowlands and forested areas of the Trask River watershed to calibrate the biogeochemical portion of the model. Hydrology calibrations using USGS river flow data achieved a Nash-Sutcliffe Efficiency of 0.85 for the period of 2007 to 2016. Our research demonstrates the utility of ecohydrology models such as VELMA to aid in watershed management decision-making related to ecosystem goods and services. Model outputs of river water flow, temperature, and nutrient concentrations can be linked with other models to predict effects on ecosystem services such as the provision of drinking water, habitat for valued salmonid populations, and improvement to estuarine water quality (important for recreation and aquaculture). This modeling effort is part of a larger framework of connected models being developed to simulate the networked hydrology and ecology of the estuary, the coastal waters, and the estuarine watersheds. This framework ultimately aims to provide a more complete model of the many factors influencing estuarine ecosystem functions and the services they provide to their associated communities.