Distributed watershed modeling

Status:

Distributed watershed modeling will be conducted using the TIN-based Real-time Integrated Basin Simulator (tRIBS; Ivanov et al. 2004; Vivoni et al. 2007). The first step in the application of tRIBS is to delineate the basin boundaries and the stream network derived from a Digital Elevation Model (DEM). A 29 meter resolution DEM obtained from the USGS National Elevation Dataset (NED; http://seamless.usgs.gov/) was processed using ArcGIS. Figure 1 shows the resulting basin boundaries for the Lower Santa Cruz and San Pedro River Basins. This figure also indicates the location of available USGS stream-gaging stations and a few geographical indicators such as towns and the US-Mexico border.

The preliminary basin boundaries and stream networks shown in this figure may be modified as other DEM products (SRTM and ASTER DEM) are also being evaluated. In addition to the figure, we also attach a ZIP file to this posting that contains the GIS shapefiles for the basin boundaries in Decimal Degrees (DD) and Universal Transverse Mercator (UTM Zone 12 North) geographic coordinate systems. These basin boundaries (from the USGS NED 29 m DEM) can be used by other participants for masking the study basins or for their own purposes. See the Download Link at the end of the post.

Figure 1. NSF-WSC Study Basins with Elevation, Boundaries and Stream Network.

Discussion:

The next step in the model setup process is to discuss the appropriateness of the basin boundaries as well as the identification of the critical reaches in the stream network. The details on the boundaries and river network are important for the groundwater modeling and hydraulic river routing portions of the integrated modeling. We would appreciate comments and suggestions from others in the group. We would also like to divide the river network into reaches for the purposes of identifying common points of interaction for the demographic scenarios and the riparian habitat efforts. Input on this in the form of existing reach delineations would be helpful. Finally, we would like to be able to overlay the basin boundaries and the gridded output mask from the second downscaled WRF model runs to see how the climate information will be mapped onto the watershed domain. This effort is currently in progress.

Future work:

1. Derive the triangulated irregular network (TIN) for each study basin with the finalized basin boundaries and channel networks.

2. Obtain and process available high-resolution soil and vegetation data layers for the entire river basins. Begin process of parameter value identification.

3. Setup numerical model in ASU Saguaro cluster for basins. Estimate model performance times for basins for specified number of processors.

4. Derive methods for transferring downscaled WRF model output to tRIBS meteorological model input.

Download Shapefiles:

http://vivoni.asu.edu/wsc/NSF_WSC_Boundary_Shapefiles.zip

References:

Ivanov, V.Y., Vivoni, E.R., Bras, R. L. and Entekhabi, D. 2004. Catchment Hydrologic Response with a Fully-distributed Triangulated Irregular Network Model. Water Resources Research. 40(11): W11102, 10.1029/2004WR003218.

Vivoni, E.R., Entekhabi, D., Bras, R.L., and Ivanov, V.Y. 2007. Controls on Runoff Generation and Scale-dependence in a Distributed Hydrologic Model. Hydrology and Earth System Sciences. 11(5): 1683-1701.