Technical Approach

A classification and assessment methodology will be developed and tested at four military installations in the southwestern United States, representing the four Southwestern ecoregions--Fort Irwin (Mojave Basin and Range), Yuma Proving Grounds (Sonoran Desert), Fort Huachuca (Madrean Archipelago), and Fort Bliss (Chihuahuan Desert). The project will begin with the acquisition and preparation of existing climatic, physical, and biological data from GIS, remote sensing, and ground-based methods for each study site. Expertise from installation resource staff will guide the identification of geographic areas of particular importance at each installation (e.g., areas of high conservation priority, species of concern, and priority areas within the channel network). Historical climate data will be gathered across the four ecoregions and coupled with topographic and geologic data to determine the seasonal hydrologic regimes of each of the study sites. Digital elevation models and imagery (including LiDAR and high resolution multispectral imagery) will be used to identify channel morphologies and riparian vegetation composition and structure along longitudinal gradients. The physically based hydrologic model AGWA/KINEROS2 will be used to develop hydrologic gradients of peak flows, flow frequency, and available surface water, and channel morphologies will be evaluated for their degree of adjustment to seasonal hydrologic inputs. Existing groundwater data (where available), riparian composition and structure, plant phenologies, and landscape position will be coupled with surface water modeling to determine the likelihood of relative surface/groundwater dependence by riparian vegetation along channel networks at each study site. Statistical approaches (e.g., classification and regression trees, multivariate regression trees) will be used to classify ephemeral and intermittent streams by these ecohydrologic properties along xeric to mesic gradients. A stream health assessment methodology will be developed that links the ecohydrologic metrics of the classification system with hydrologic modeling to evaluate the impacts of climate change, training activities, and land management decisions on channel health and habitat values.