Citation:

Aho, K., S. Leibowitz, M. LaCroix, AND J. Flotemersch. Index of Watershed Integrity - Matanuska-Susitna Basin. Matanuska Susitna Results Teleconference, Corvallis, Oregon, August 28, 2018.

Impact/Purpose:

The EPA’s Index of Watershed Integrity (IWI) is used to calculate and visualize the status of natural watershed infrastructure that supports ecological processes (e.g., nutrient cycling) and services provided to society (e.g., subsistence resources). The IWI applied to the conterminous US defined watershed functions specific to running water. However, seasonal ice affects 58% of North America’s streams and rivers. This Alaskan iteration of the IWI focuses on the needs of state partners (e.g., Alaska Department of Environmental Conservation). An Alaska IWI that includes stressors to surface (e.g., glaciers), sub-surface (e.g., permafrost), and seasonal (e.g., river ice) cold-climate hydrology features could provide insights on seasonal functions, both for Alaska and regions of the CONUS that experience a degree of river ice during the winter. This is done using the National Hydrography Dataset Plus High Resolution, information from landscape metrics (e.g., National Land Cover Database), and cold-climate data (e.g., rain on snow events) from the University of Alaska Fairbanks.

Description:

The US Environmental Protection Agency’s (EPA) Index of Watershed Integrity (IWI) is used to calculate and visualize the status of natural watershed infrastructure that supports ecological processes (e.g., nutrient cycling) and services provided to society (e.g., subsistence resources). Specifically, the IWI is based on six functions that watersheds with high integrity are hypothesized to provide: hydrologic regulation, regulation of water chemistry, sediment regulation, hydrologic connectivity, temperature regulation, and habitat provision. To assess the integrity of these six functional components, the IWI accumulates the occurrence of stressors, or risk factors (e.g., agricultural land cover, road-stream intersections, impervious surfaces) downstream. The IWI has been applied to the conterminous US and to international basins in the western Balkans. To better support regional decision-making bodies (e.g., States), the EPA has produced an IWI for the Matanuska-Susitna Basin (AK IWI). Our goal for this project is to incorporate region-specific stressors to streams and cold-climate features that are actionable by the State of Alaska. To accomplish this, we explored the inclusion of region-specific stressors and the inclusion of stressors specific to cold-climate hydrology. During this teleconference with state and federal partner agencies, we will use the results as a platform for co-developing management applications for the AK IWI results.

Record Details: