Citation:

Halama, J., Bob Mckane, A. Brookes, Joe Ebersole, B. Barnhart, P. Pettus, P. Wingo, R. Kennedy, J. Graham, J. Cushing, AND K. Djang. Dynamic Shade and Irradiance Simulation of Aquatic Landscapes and Watersheds. Society for Ecological Restoration Northwest Regional Conference, Portland, OR, April 04 - 08, 2016.

Impact/Purpose:

This abstract is for an oral presentation at the 2016 SERNW Conference, April 4-8, 2016, Portland, OR (http://chapter.ser.org/northwest/2016-regional-conference). The conference is sponsored by Northwest Forest Soils Council, Center for Natural Lands Management, Northwest Association of Environmental Professionals. Stream temperatures are directly and indirectly affected by solar radiation. Numerous spatially distributed models work toward simulating landscapes to help stakeholders better understand their streams and watersheds, but these models lack the necessary solar radiation simulation capability or multidimensional irradiance data needed to provide private landowners, watershed councils, or local governments with a representative or comprehensive understanding of how solar energy is driving change throughout their areas of interest. This study addresses the need for a spatially distributed shade and irradiance model capable of both stand-alone and external model integration. Specifically, this model concentrates on the need to understand how solar energy is spatially and temporally distributed across watersheds. Accounting for irradiance can improve simulations of ecological processes critical to stream temperature modeling at stream reach and watershed scales. The 2016 SERNW Regional Conference will particularly benefit from this model and study results because it will help to improve habitat modeling and will increase current and future restoration projects’ odds of success regarding the improvement of critical habitats for salmonid and other species. Initial studies are focusing on solar radiation distribution across Washington’s Nisqually River watershed and Oregon’s Calapooia River watershed. As part of EPA’s Sustainable and Healthy Communities Research Program, study results are also being used to help address other community concerns, such as the establishment of a Nisqually Community Forest.

Description:

Penumbra is a landscape shade and irradiance simulation model that simulates how solar energy spatially and temporally interacts within dynamic ecosystems such as riparian zones, forests, and other terrain that cast topological shadows. Direct and indirect solar energy accumulates across landscapes and is the main energy driver for increasing aquatic and landscape temperatures at both local and holistic scales. Landscape disturbances such as landuse change, clear cutting, and fire can cause significant variations in the resulting irradiance reaching particular locations. Penumbra can simulate solar angles and irradiance at definable temporal grains as low as one minute while simulating landscape shadowing up to an entire year. Landscapes can be represented at sub-meter resolutions with appropriate spatial data inputs, such as field data or elevation and surface object heights derived from light detection and ranging (LiDAR) data. This work describes Penumbra’s framework and methodology, external model integration capability, and appropriate model application for a variety of watershed restoration project types. First, an overview of Penumbra’s framework reveals what this model adds to the existing ecological modeling domain. Second, Penumbra’s stand-alone and integration modes are explained and demonstrated. Stand-alone modeling results are showcased within the 3-D visualization tool VISTAS (VISualizing Terrestrial-Aquatic Systems), which fluently summarizes the complex light phenomena Penumbra simulates. Penumbra integration is demonstrated within a spatially distributed watershed simulator – VELMA (Visualizing Ecosystem Land Management Assessments) and the SSN (Spatial Stream Network) model. Two watershed-scale modeling projects—Nisqually River, Washington and Calapooia River, Oregon—are used as examples to demonstrate the effectiveness and utility of Penumbra. With ongoing development, Penumbra can provide sufficient shade or irradiance assessments at spatial resolutions and temporal scales which are suitable for assisting watershed stakeholders with their riparian restoration and adaptive management projects.

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