Consequence Analysis Module for DSS-WISE™ Lite

The new version of the DSS-WISE™ Lite system funded by FEMA has been operational since November 8, 2016. This system provides web-based, automated, two-dimensional dam/levee break modeling and mapping to FEMA, dam safety stakeholder agencies, and state dam safety offices. The numerical solver uses a finite volume model to solve full dynamic shallow water equations over complex topography represented by a regular Cartesian mesh. The shock-capturing scheme uses HLLC (Harten-Lax-van Leer with Contact wave) approximate Riemann solver to compute intercell fluxes by taking into account wetting and drying. The Cartesian computational mesh is automatically prepared from 1/3 arc-second USGS NED. The U.S. Army Corps of Engineers (USACE) levees recorded in the National Levee Database are burned into the Cartesian mesh. Manning’s friction coefficient values are assigned based on the classified land-use data from NLCD 2011. Unknown reservoir topography is estimated based on the user specified volume-stage data pairs using a skeletonization algorithm enhanced with heuristics. The simulations are provided with resolutions from 20 ft. to 200 ft. Additional information can be found in Altinakar et al. (2017).

As of 8/10/2017, the system handled 1,543 simulation jobs launched by stakeholder agencies and state dam safety offices with a success rate of 72%. The system has currently 183 active users and 11 new users were added during the last 7 days. There are 35 candidate users waiting to be activated by the group leaders. The number of simulations submitted during the last 30 days is 260 corresponding to 8.7 simulations per day on average. For about 70% of the simulations, the results are provided within half an hour.

The exceptional computational speed of its solver, and the short time (less than 10 minutes) needed to set up a simulation, led DSS-WISE™ to be used as a real-time operational tool during various dam-safety emergencies. For example, Dam Safety engineers at the California Department of Water Resources used DSS-WISE™ Lite to prepare inundation maps during the Oroville Dam incident in February 2017.

DSS-WISE™ Lite provides a large range of GIS-compatible results files that can be used for inundation mapping. These files can be opened in any third-party GIS software package.

This proposal concerns the development and implementation of a consequence analysis module for DSS-WISE™ Lite, which has been identified as a high-priority objective by FEMA. The proposed module would allow the performing of the following tasks:

• Analysis of the time variation of PAR (Population at Risk) by selected age groups, as represented in the Census Block/Tract data.

• Loss-of-life analysis using the new USBR methodology.

• Preparation of danger maps for humans.

The results of the analysis will be made available for download on the Status and Results page of DSS-WISE™ Lite, together with an automatically-generated PDF report.