Fire, forests, floods, and freshwater forecasting:
 Cyberinfrastructure to assemble disparate data sources into high performance models of watershed ecohydrology for science discovery and sustainable management

Abstract:
The protection and restoration of watersheds is one of our major environmental challenges. We describe a cyberinfrastructure, RHESSys (Regional Ecohydrologic Simulation System) designed to assemble environmental observations, evolving science-based theory and socio-economic information into high performance models and visualization of watershed ecohydrology for science discovery and sustainable management. RHESSys combines biophysical science-based theory, data-driven empirical models with spatial data sets (such as remote sensing imagery), sensors (e.g. carbon flux, streamflow or groundwater levels) and meteorologic time series from observations and climate models. RHESSys architecture include a core set of models in C code (https://github.com/RHESSys/RHESSys), and a set of workflows built in Python and R to support data assimilation, calibration and sensitivity analysis and output visualization and analysis. RHESSys has been applied to a wide range of environmental change and management challenges throughout the globe, focusing primarily at smaller watershed scales (1-100 km2). We describe two applications of recent focus: climate change impacts in semi-arid regions and the role of green infrastructure in urban environments. 

The recent decades have brought increasing temperature and precipitation extremes (floods and droughts) to the semi-arid Western US and Mediterranean regions throughout the globe. Consequences have been dramatic, and include increasing fire severity, forest mortality and reduced summer water supply. Sustainable management of these systems under stress require estimates of future trends and analysis of how strategies such as fuel treatments might mitigate them. Spatial heterogeneity in climate, vegetation, geology in these regions also means that broad brush (e.g. continental scale) frameworks often miss critical patterns that can determine not only the magnitude but also direction of responses. We apply RHESSys at scales that can capture watershed to watershed variation in, for example, how changing snowpacks translate to streamflow or how future fire regime and forest health might response to forest management 

In degraded urban watersheds, restoration of vegetation canopy and hydrologic drainage seeks to reproduce the “ecosystem services” provided by natural watersheds. Green infrastructure (GI) is an innovative approach to design, build and restore urban watershed and ecosystem sustainability to reduce stormwater volumes, pollutant loads, urban heat islands, and improve carbon sequestration and air quality. Any restoration project involves modifying public, institutional or private property; successful GI implementation depends on community support and participation in design. An aid to participatory design is the deployment of collaborative environmental modeling and visualization software to represent restoration scenarios at meaningful scales to residents and other stakeholders, and allow design through easy-to-use interfaces. 

Central to all of our applications of RHESSys is visualization of output. Because we work at neighborhood, hillslope and smaller watershed scales, we have opportunities to use model input and output to create dialogues with field scientists, support inter-active scenario planning by managers and communities, and improve science communication. We show some recent advances in integrating RHESSys output into dynamic interactive visualization. 

Bios
Naomi (Christina) Tague’s research uses advanced data science techniques to understand how water, plants, geology and climate interact in a tightly coupled system – and how humans are changing this system. Much of her work involves designing advanced simulation models that integrate data from multiple sources including field and lab experiments and data from remote sensing technologies. These models are ‘virtual laboratories’ that we can use to explore ‘what- if’ scenarios with best available science. In these labs, we can ask ‘what will happen to water supply from snow-dominated mountain watersheds as climate warms”, “how do different vegetation types in green infrastructure effect water and nitrogen cycles”, “how do fuel treatments in different locations influence fire severity”, and many other questions about water resources and ecosystems. 

Tague is a professor at the Bren School of Environmental Science and Management, at the University of California, Santa Barbara, where she teaches courses in environmental modeling, climate change and forest sustainability and advises students in a Professional Masters program that focuses on applied environmental problem solving and communication. She has recently co-developed a new Masters in Environmental Data Science. Her research is highly collaborative, working with biophysical scientists, computer scientists and social-scientists across the US and in Canada, China , Spain and Israel. She is active within the American Geophysical Union, The Consortium of Universities for the Advancement of Hydrologic Science and serves on the Science Advisory Board of the California Forest Management Task Force. More information can be found at TagueTeamLab.org 

Larry Band is the Ernest Ern Professor of Environmental Science and Professor of Engineering Systems and Environment at the University of Virginia. Band’s research is on watershed hydrology and ecology, including the effects of climate and land use change on flooding, drought, stormwater and water quality. This includes the study of environmental resilience in forest and urban environments, and the use of ecosystem principles as design guidelines for developing more sustainable urban and rural landscapes. He has worked in field sites in the US, Canada, Australia and China, and has worked with federal, state and municipal agencies in the US and Canada on watershed protection, forest health, stormwater and ecosystem restoration. Last year he was a contributing author to the 4th National Climate Assessment, collaborating on assessing the effects of climate change on the nation’s forests. Band has consulted with federal, state, provincial and municipal agencies in the US and Canada on watershed protection, forest health and carbon sequestration, stormwater and ecosystem restoration. 

Until 2017 Band was the Director of the Institute for the Environment at the University of North Carolina, Chapel Hill. Band is a Fellow of the American Geophysical Union and Geological Society of America (GSA). He was the 2014 GSA Birdsall-Dreiss Distinguished Lecturer, giving 50 talks on the effects of climate and land use on the ability of forests to provide freshwater supplies, sequester atmospheric carbon, and on the ecology and hydrology of urban green infrastructure.