Citation:

SEMMENS, D. J., S. N. MILLER, AND D. C. GOODRICH. TOWARDS AN AUTOMATED TOOL FOR CHANNEL-NETWORK CHARACTERIZATIONS, MODELING, AND ASSESSMENT. Presented at 3rd Federal Interagency Hydrologic Modeling Conference, Reno, NV, April 02 - 06, 2006.

Impact/Purpose:

The primary objectives of this research are to:

Develop methodologies so that landscape indicator values generated from different sensors on different dates (but in the same areas) are comparable; differences in metric values result from landscape changes and not differences in the sensors;

Quantify relationships between landscape metrics generated from wall-to-wall spatial data and (1) specific parameters related to water resource conditions in different environmental settings across the US, including but not limited to nutrients, sediment, and benthic communities, and (2) multi-species habitat suitability;

Develop and validate multivariate models based on quantification studies;

Develop GIS/model assessment protocols and tools to characterize risk of nutrient and sediment TMDL exceedence;

Complete an initial draft (potentially web based) of a national landscape condition assessment.

This research directly supports long-term goals established in ORDs multiyear plans related to GPRA Goal 2 (Water) and GPRA Goal 4 (Healthy Communities and Ecosystems), although funding for this task comes from Goal 4. Relative to the GRPA Goal 2 multiyear plan, this research is intended to "provide tools to assess and diagnose impairment in aquatic systems and the sources of associated stressors." Relative to the Goal 4 Multiyear Plan this research is intended to (1) provide states and tribes with an ability to assess the condition of waterbodies in a scientifically defensible and representative way, while allowing for aggregation and assessment of trends at multiple scales, (2) assist Federal, State and Local managers in diagnosing the probable cause and forecasting future conditions in a scientifically defensible manner to protect and restore ecosystems, and (3) provide Federal, State and Local managers with a scientifically defensible way to assess current and future ecological conditions, and probable causes of impairments, and a way to evaluate alternative future management scenarios.

Description:

Detailed characterization of channel networks for hydrologic and geomorphic models has traditionally been a difficult and expensive proposition, and lack of information has thus been a common limitation of modeling efforts. With the advent of datasets derived from high-resolution mapping techniques such as LIDAR (light detection and ranging), however, it is possible to resolve a great deal of information useful for hydrologic and geomorphic modeling. A channel-characterization tool is being developed to automate the extraction and reduction of data from high-resolution digital elevation models (DEMs) to derive meaningful information about channel morphology at a reach scale. The tool, with some initial guidance from users, will automate the process of extracting cross-sections, at user-defined intervals, perpendicular to channels throughout a watershed channel network. In the current version some user interaction is still needed to identify channel banks, but the tool is able to extract channel and flood-plain characteristics for ephemeral stream networks. Channel characteristics derived using the new tool were compared with field measurements and mapping to evaluate performance on the USDA-ARS Walnut Gulch Experimental Watershed in southeastern Arizona. The channel characterization tool was designed to compliment the Automated Geospatial Watershed Assessment (AGWA) tool by facilitating parameterization of the Kinematic Runoff and Erosion model (KINEROS2). It is anticipated that future versions of the tool will incorporate vegetation characterization along riparian corridors. This information will further assist with hydrologic model parameterization, and can also be combined with geomorphic conditions/indicators and output from the hydrologic models to evaluate channel condition and vulnerability on a reach basis.

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