Modeling alternative future land use and climate change scenarios (1990–2100) for all major Puget Sound river basins (~30,000 km2)
Citation:
Halama, J., R. McKane, A. Brookes, S. Chokshi, AND K. Djang. Modeling alternative future land use and climate change scenarios (1990–2100) for all major Puget Sound river basins (~30,000 km2). To be Presented at Salmon Recovery Conference, Vancouver, WA, April 18 - 19, 2023.
Impact/Purpose:
The main objective of this research has been to establish a scientifically sound watershed simulation model that can help inform stormwater management decisions by communities, tribes, and government agencies seeking green infrastructure solutions for reducing runoff of 6PPD-quinone and other toxic chemicals in urban runoff impacting salmonids and other sensitive species. Key component of this research is a holistic perspective through a multi-model integration to provide a better understanding of ecosystem services under alternative scenario plans. Results from these simulations will be fed into the Salish Sea Model for nutrient and contaminant cycling that will be fed into the Atlantis food web model.
Description:
Visualizing Ecosystem Land Management Assessments (VELMA) is an ecohydrology model being leveraged in a recently initiated effort to identify practical, proactive watershed restoration strategies that can be initiated now to lessen long-term impacts of climate change on Puget Sound communities. This effort is particularly pertinent to tribal communities and the salmonid populations essential to their sustenance, health, and culture. Consistent with the goal of fulfilling United States tribal treaty obligations in State of Washington, we will assist tribal environmental restoration managers to increase ecosystem and community resilience to climate change, focusing on Salish Sea salmonid-bearing watersheds that the tribes and State of Washington co-manage for salmon recovery and habitat protection. Extending existing region Tribal and partner experience with VELMA, we will co-develop watershed Best Management Practices (BMPs) for mitigating long-term impacts of climate change. VELMA will model for alternative future land use and climate change scenarios (historical 1990 up to 2100) for all major Puget Sound basins (~30,000 km2) to simulate impacts of changing terrestrial nutrient loads on observed historical declines and potential future degradation vs. BMP-based recovery trajectories for marine nutrients and sensitive biota. VELMA outputs will be used to assist communities, tribes, and state and federal decision makers in determining how much, where, and what kinds of urban and rural BMPs are required to achieve target nutrient load reductions to the Puget Sound estuary, now and in the future. The end goals of this ambitious research will be accomplished through model-coupling the Environmental Protection Agency (EPA) VELMA (terrestrial ecohydrology), Pacific Northwest National Laboratory (PNNL) Salish Sea Model (estuarine circulation and biogeochemistry), National Oceanic and Atmospheric Administration (NOAA) Atlantis (estuarine food web) models. The modeling spatial extent are being set up for the entire Puget Sound region and its contributing watershed basins to support a holistic, whole-ecosystem approach to regional planning and restoration decision-making, capable of assessing land and water ecosystem service trade-offs and co-benefits under alternative climate, population, and land use futures for a broad range of regional objectives, from orcas to human wellbeing. Within this framework, VELMA terrestrial water quality outputs under alternative land use and climate scenarios to Salish Sea Model which, in turn, feeds it marine water quality outputs to Atlantis estuarine food web model (microbes to orcas). The Land Cover Change Model (LCCM) will inform VELMA’s alternative scenarios. This progressive modeling effort will provide enhanced decision support regarding revitalization of community health and well-being, specifically for Puget Sound tribes reliant on declining Endangered Species Act (ESA) listed salmonid populations for their subsistence and cultural well-being. But most Puget Sound communities with any contact with the region will derive health benefits from habitat enhancements resulting from this research. Key to this goal are terrestrial-marine salmon habitat improvement practices consistent with tribal treaty rights, along with remediation of toxic stormwater contaminants that bioaccumulate in salmonids and, ultimately, tribal consumers.