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I I I I I I I I I I I I I I I I I I I AYRES Ayres Associates' engineers have significant experience with 2-dimensional modeling and have been pertorming 2-dimensional modeling since 1990. In addition to the flow visualization tools available with the 2-dimensional model software, in that time we have developed additional.~post-processing" tools to enhance flow visualization for clients, public education. and litigation support. For this project. we propose tailoring specific flow visualizations for use in demonstrating the validity 01 the results to the project sponsors and public. For example, a detailed 2-dimensional model was developed to support channel restoration design on the Santa Ana reach of the Rio Grande near Albuquerque, New Mexico. The 2.dimensional model output tor existing conditions and various reclamation alternatives was post.processed to determine the amounts of preferred habitat for the endangered silvery minnow. Similarly, output from a 2.dimensional model of a portion of the Yampa River in Colorado was post- processed to identify that the endangered Colorado Pike Minnow's preferred spawning habitat on riffles has high shear stress at low flow and low shear stress at high flow. One useful post-processing tool is a "streamline tool" that was developed by Or. Zevenbergen as part of a court case. The streamlines track the path of flow downvalley. This tool has been used on other projects to illustrate flow paths down hydraulically complex floodplains. This is illustrated in Figure B. which depicts flow paths (streamlines) computed from a 2-dimensional model of a partially leveed reach of the Sacramento River. In Figure 8. the yellow streamlines divide the total flow into equal discharge (10 percent interval) flow areas. For the South Boulder Creek project. the streamlines can be drawn over topographic mapping or aerial photographs 10 illustrate flow paths over recognizable features. , , , Figure B. Water surlace contours (blue) and streamlines (yellow) along Butte Basin reach of the Sacramento River (flow is from top to bottom). 21