2012 Annual Report 1a.Objectives (from AD-416): Establish a scientifically defensible means of representing and modeling the effects of Clean Water Act-related stream-channel and stormwater management actions at a basin scale, and then to evaluate the cumulative basin-wide sensitivity to alternative management practices resulting from multiple permit applications and/or future landscape scenarios. 1b.Approach (from AD-416): Approach: (1) Incorporate the ability to emulate different growth scenarios, (2) incorporate tools and parameter sets that will support the modeling of different best management practices, (3) provide a complete spatial database for the entire San Pedro River basin and (4) provide training to EPA Regional and ORD personnel on use of the modified AGWA tool. 3.Progress Report: In FY12 a methodology and associated report was developed to incorporate projected land cover change projections from 2010 to 2100 on ten-year increments derived from several growth and immigration scenarios developed by the Environmental Protection Agency (EPA) Integrated Climate and Land Use Scenarios (ICLUS) project. A procedure was developed to merge the projected impervious land cover change layers with existing, non-urban, land cover layers. Watershed models within the Automated Geospatial Watershed Assessment (AGWA) tool were then run on the San Pedro river basin in northern Sonora, Mexico and southeastern Arizona to assess the change in watershed response for an number of model output (runoff, erosion, sediment yield, etc.) from the current (2010) condition to each of the decadal projected land covers for one of the growth scenarios. The methodology was accepted by our EPA collaborators and we are now repeating the analysis on the other growth scenarios. In addition, a number of enhancements to AGWA were identified as part of AGWA training conducted early in the project. These enhancements are being programmed into AGWA and will be demonstrated during a second AGWA training that will occur in the fall of 2012 or the spring of 2012. This project was also amended and additional funds were added to it to assess whether AGWA and the KINEROS2 watershed model could be used to represents the impact of Low-Impact Development (LID) methods in arid and semi-arid areas. KINEROS2 was modified to represent:. 1)Pervious or infiltration pavement,. 2)Rain water harvesting; and,. 3)green or infiltrating drainage channels. The model was then applied to a well instrumented development in Sierra Vista, Arizona. Results were presented at Arid LID conference in Tucson, Arizona, in April 2012. This project contributes to objective 3 of the in-house project.