Derived Triangulated Irregular Network (TIN) for each study basin with the finalized basin boundaries and channel networks

•    A Digital Elevation Model (DEM) with a resolution of about 29 meters obtained from the National Elevation Dataset (NED) was used to generate the basin boundaries, channel networks and deriving the TINs for the Santa Cruz and San Pedro River basins.

•    TINs were derived using the TIN Index Analysis Program (TIAP). The preprocessing of the DEM included the extraction of a floodplain from the DEM to be used in the Terrain method (slope based) that was used to generate the TINs.

•    The terrain or slope criteria method is based on the topographic relevance of DEM points in describing the terrain. Regions with drastic elevation changes (rugged) are characterized with a much higher resolution, whereas flatter areas have a lower resolution, except in the floodplain areas where high resolution is retained.

•    We generated TINs at various resolutions which resulted in the decision to use a coarser resolution for the larger domains (Santa Cruz and San Pedro watersheds) and a higher resolution for the smaller domains (Box Canyon and Walnut Gulch subbasins).  The stream network used for the large domains has a threshold area of about 10 km², whereas the smaller domains have a channel upslope area of 0.03km².

•    The TINs of the entire NSF-WSC domain including the higher resolution smaller domains are shown in Figure 1. Notice the high resolution around the regions where the smaller domains are located.

 

 Figure 1. Final derived Triangular Irregular Network’s (TINs) for the NSF-WSC study area.