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INTEGRATING LANDSCAPE AND HYDROLOGIC ANALYSIS FOR WATERSHED ASSESSMENT IN AN AMERICAN SEMI-ARID BIOREGION
Citation:
Kepner, W G., M. Hernandez, D J. Semmens, D W. Ebert, D. C. Goodrich, AND S. N. Miller. INTEGRATING LANDSCAPE AND HYDROLOGIC ANALYSIS FOR WATERSHED ASSESSMENT IN AN AMERICAN SEMI-ARID BIOREGION. Presented at 6th International Association for Landscape Ecology World Congress, Darwin, Australia, July 13-17, 2003.
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:
The objective of this study is to demonstrate the application of operational hydrologic modeling and landscape assessment tools to investigate the temporal and spatial effects of varying levels of anthropogenic disturbance in a semi-arid catchment and examine the consequences of landscape change on runoff volume and soil erosion.
We integrated landscape metrics generated from readily available spatial data with a hydrologic model to examine the temporal and spatial effects of varying levels of anthropogenic disturbance between 1973 and 1997 in the Upper San Pedro River in southeastern Arizona. Landscape pattern analysis was conducted on a sub-catchment basis with emphasis on different levels of human use. Landscape metrics were associated with landscape characteristics, human stressors, and physical characteristics at each sub- catchment and for four temporal land use layers (1973, 1986, 1992, and 1997). Chronological changes were then examined relative to catchment condition variables using two hydrological models to perform multi-scale watershed assessment for a variety of outputs such as runoff depth, runoff discharge, and erosion rates at the sub-catchment scale. The results were particularly useful for assessing the effects of anthropogenic disturbance in the catchment area over a period of 25 years and for identifying sub- catchments that require critical management attention.